Demagnetization is the process of reducing the magnetization of various metal objects.
Demagnetization is required in various fields of technology.
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In production, when working with tools, it is inconvenient to use a magnetized screwdriver or tweezers, small nuts and washers "stick" to the tool.
When processing products on machines, it is necessary that the metal part does not move after the moving devices of machines and units.
The main method of demagnetization is the impact on a magnetized object by an alternating magnetic field with a decreasing amplitude. Sometimes materials are demagnetized by heating to a certain high temperature.
Ship hulls, technical equipment, weapons, built of ferromagnetic materials, being in the Earth's magnetic field, are magnetized.
The magnetization of the ship consists of:
1) magnetization, which is acquired by the ship during its construction or long-term parking, the ship becomes a "permanent magnet";
2) magnetization, which is acquired by the ship at a given time, depending on the magnitude and direction of the Earth's magnetic field. It continuously changes with the change of the Earth's magnetic field and disappears if the Earth's magnetic field at the ship's location becomes equal to zero. This is how ships acquire their own magnetic fields.
Permanent magnetization is removed on special coastal or other mobile stands, and the magnetization obtained as a result of the action of the Earth's magnetic field is compensated using a demagnetizing device installed on the ship itself.
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Ships with a magnetized hull attract floating metal objects, and sea mines can become them. The ship's compass begins to give erroneous readings, mistaking the ship's magnetic field for the Earth's magnetic field. Therefore, in order to protect against sea mines and to increase the accuracy of the readings of the magnetic compass, both surface and underwater ships are subjected to demagnetization.
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The first non-contact magnetic mines appeared as early as 1919. In such mines, the iron arrow turned under the influence of the magnetic field of a ship sailing nearby and closed the fuse contacts. For such mines, it was not even necessary to touch the ship's hull!
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In the 30s of the 20th century, our scientists proposed to “demagnetize” the ships.
In 1937, the first successful experiments were carried out in Russia to demagnetize ships in Kronstadt.
In 1939, the demagnetized ship "Vyborny" successfully navigated over magnetic mines in Lake Onega.
In 1941, there was a transition to the stationary equipment of ships with demagnetizing installations (current-carrying windings that level the hull magnetization).
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During the Great Patriotic War, the demagnetization of submarines was of great importance, which was carried out without fail before they went to sea. Each boat had a special passport, which noted the state of its magnetic field. Degaussing saved more than one submarine from sinking
The principle of submarine demagnetization is as follows. The demagnetizing device consists of several (3 or 4) windings.
A direct current is passed through each winding in such a direction and such that the magnetic field it creates is equal and opposite to one of the components of the magnetic field of the boat.
Did you know?
magnets and the brain
Physiologists have found that the use of a magnetic field contributes to the development of the brain in adults, the elderly and children.
Researcher Fortunato Battaglia from New York University, after conducting experiments, found that exposure to magnetic fields leads to the growth of new neurons in areas of the brain reserved for memory and learning. Magnetic brain stimulation has long been used to treat depression, schizophrenia, and the effects of strokes, in which magnetic fields restore speech to those affected. If new studies are confirmed, then doctors will have new prospects for treating various diseases (for example, Alzheimer's disease, which is accompanied by massive death of brain neurons) and correcting age-related changes in memory.
inquisitive
White clouds
Why are clouds mostly white and not blue like the sky? Why are thunderclouds black?
Turns out...
Scattering of light by objects much smaller than the wavelength of visible light is described by the Rayleigh scattering model. Water droplets in a cloud are usually larger and light is simply reflected from their outer surface. With this reflection, the light does not decompose into its component colors, but remains white. Very dense clouds appear black because they allow little sunlight to pass through - it is either absorbed by the water droplets in the cloud or reflected upward.
Degaussing of Black Sea Fleet ships during the Great Patriotic War Viktor Dmitrievich Panchenko
Windless degaussing of ships. Organization SBR-1, SBR-2, SBR-3. Polygon for checking the quality of demagnetization. Development of an automatic current regulator in course windings
The first experiments on windless demagnetization of submarines under the leadership of A.P. Aleksandrov were started even before the order of the commander of the Black Sea Fleet on September 10, 1941. They were carried out in the South Bay, near the piers of the 1st submarine brigade, on July 4–5 ) and July 23–25 (L-5). In both cases, encouraging results were obtained. Later, on August 17 and 20, 1941, the British officers, who were then in Sevastopol, carried out a demonstrative non-winding demagnetization of the S-32 and M-111 submarines. Subsequently, this work was carried out without the participation of the British under the guidance of LPTI scientists.
The first floating station for windless demagnetization of ships (SBR-1) was equipped on a non-self-propelled metal barge SP-98 with a displacement of about 150 tons. Everyone understood that it would be good for the SVR to use a self-propelled ship with a wooden hull so that it would not interfere with its magnetic field, but by this time all the mobilized ships were already adapted for the various needs of the Navy, for example, for minesweeping, transportation of ammunition, food and small cargoes.
As power sources, the SBR-1 was equipped with a battery of 60 cells of the KSM type, taken from a submarine of the Shch type, where it had already worked out the prescribed period, but was still suitable for operation in the SBR conditions. In addition, a control panel with switching equipment and devices was installed, and several hundred meters of HPM type cable were received.
The SBR-1 staff initially consisted of 12 people, including the chief, an engineer, two electricians and a boatswain team.
On August 25, SBR-1 began work on windless demagnetization of ships. For the technical guidance of these works, until the officers mastered the methods used, the crew was temporarily seconded by the LPTI researcher Yu. S. Lazurkin, the designer of the TsKB-52 Volovich, and the engineer of the Technical Department of the Black Sea Fleet Rabinovich. M.A. Gorbunov, a military engineer of the III rank, whom I.D. Kokorev and I knew well, was appointed head of the SBR-1. A military engineer of the 1st rank, N. A. Biyatenko, was appointed engineer of the RRF.
Mikhail Alekseevich Gorbunov, after graduating from the St. Petersburg Electrotechnical Institute in 1914, was called up for service in the Navy and was appointed to the position of hold mechanical engineer on the Pylkiy destroyer of the Black Sea Fleet. The revolution caught him on the Volga military flotilla, and after the end of the civil war, he was transferred to the reserve and worked in the electrical industry. Mikhail Alekseevich had many years of experience in installation and commissioning at many power plants of the Soviet Union, he was a highly qualified specialist and knew how to work with people. From the first days of the war, he was drafted into the Navy and served as a senior engineer in the Energy Department of the Technical Department of the Black Sea Fleet.
Nikolai Alekseevich Biyatenko, a graduate of the Kharkov Electrotechnical Institute, before the war worked at KhEMZ as a senior engineer in the hardware department and was a good specialist.
The recruitment of the SBR-2 team began, and a little later, the SBR-3 team. M. G. Alekseenko, a graduate of the Naval Academy, engineer-captain of the III rank, M. G. Alekseenko, was appointed head of the SBR-2, to ensure the work on degaussing the ships, the LPTI researcher E. E. Lysenko, the engineer of TsKB-52 Bogdanov and the head of the laboratory were temporarily seconded to the crew Second rank military engineer of the 2nd submarine brigade A. S. Shevchenko.
For SBR-2, a small self-propelled fishing schooner with a displacement of about 37 tons was selected and received. Its hull was badly damaged, but there was no other, more suitable vessel at that time. A battery of 20 elements of the KSM type and a control panel were installed on it. The required amount of cable was allocated. The schooner was intended for windless demagnetization of submarines of the 2nd brigade (small boats). On September 22, after the end of the equipment, she left Sevastopol on her own for Feodosia. At the end of September, the head of the Technical Department of the Black Sea Fleet reported to Moscow that two RRFs had been formed and were already working at the Black Sea Fleet and six specialists had been trained.
For the SBR-1 and SBR-2, one English "pistol" type magnetometer was allocated (they were received at the end of August 1941) and one domestic LPTI magnetometer of the "turntable" type. British magnetometers were designed to measure only the vertical component of the ship's magnetic field against the background of the vertical component of the earth's magnetic field. They were built on the induction principle, had no rotating parts and were more convenient to use.
For SBR-1 in Sevastopol, a stand was chosen in the Kilen Bay area and equipped with cruising barrels for placing ships on them on two main courses. The depth of the stand was 12–14 m.
Already the first months of work showed that the capacity of SBR-1 should be increased. It can simultaneously carry out the processing of two ships, placing them on both sides of the SBR at a certain distance from the sides and from each other. This required a change in staffing; great difficulties and inconveniences were represented by the lack of own power of the SVR: she had to wait for tugs for a long time to be transferred for battery charging. In addition, during enemy air raids, ships that were on degaussing left the stand, and SBR-1 remained alone in the bay, as a target for "aimed" bombing.
In the future, we always strived to ensure that all RRFs were self-propelled, but fate sometimes pleased ... at the behest of the senior authorities to throw us non-self-propelled barges with a displacement of up to 450 tons. special rooms for work and to comfortably accommodate the team. However, all these charms paled before the shortcomings associated with the lack of their own course.
By the nature of its activity, the SBR was an operational technical means of ensuring the activities of the warships of the fleet. The experience of the war years and later showed that the SBR should, without the help of tugboats, on their own, make transitions not only within the same port, but also between different ports or places of permanent or temporary basing of ship formations, areas of trawling, exercises and preparation of operations. So, for example, during the minesweeping of magnetic and induction mines in the Sea of Azov, where more than 100 boat electromagnetic minesweepers were simultaneously operating, it was necessary to systematically measure the magnetic fields of the entire armada, and in the event of strong hull shaking from explosions of mines to be etched, windless demagnetization should be performed. Due to the large amount of work, minesweepers worked almost around the clock, "without taking the trawl out of the water." Breaks to move to the RRF base port and measure magnetic fields were highly undesirable. Therefore, in order to conserve the motor resources of the minesweepers and their more efficient use, the trawling brigade or detachment was attached to the SBR, which served them and wandered along with them from one trawling area to another. There were other cases when it was necessary to maneuver with technical means to perform a large amount of work in a short time, for example, in preparation for landing operations or exercises.
The principle of windless demagnetization of ships is based on the following provisions of ferromagnetism.
It is known that any ferromagnetic body placed in an external magnetic field receives inductive and permanent or residual magnetization. The magnetic field near the body from inductive magnetization in a weak external field, which is the terrestrial magnetic field, depends on its magnitude and direction, i.e., on the geomagnetic latitude of navigation and the course of the ship. The magnetic field from permanent magnetization results from the phenomenon of hysteresis. The magnitude of residual magnetization increases greatly if a constant magnetic field and elastic stresses (vibrations, shocks, etc.) or constant and alternating magnetic fields act simultaneously on a ferromagnetic body.
Under natural terrestrial conditions, the directions (signs) of the magnetic fields of inductive and permanent magnetizations coincide and the total magnetic field, including its vertical component, is summed up.
In order to reduce the vertical component of the ship's magnetic field strength, it is obviously necessary to magnetize the ship in such a way that the vertical component of the permanent magnetization strength is equal in magnitude and opposite in sign to the vertical component of the ship's inductive magnetization. Strictly speaking, it was not demagnetization, but magnetization by the non-winding method of the ferromagnetic masses of the ship.
To do this, along the contour of the ship, approximately at the level of the waterline, a thick flexible cable was hung on the hemp ends. When a current is passed through it, the sides of the ship are magnetized. Often, to enhance the effect, the wide belts of the sides of the ship were magnetized by moving (rubbing) the cable in the vertical direction at the moment the current was passed. If the current strength is very high, then the cable is attracted to the board so strongly that there is not enough strength to move it manually. On large merchant ships, cranes, winches, etc. were used to move the cable at the time the current was passed.
The elimination of the permanent longitudinal and transverse magnetization of the ship by the non-winding method was carried out in the truest sense of the word, i.e., by demagnetization.
The method of windless demagnetization of ships with its modifications, with proper work experience, turned out to be quite flexible and made it possible to protect submarines, auxiliary vessels and small ships from enemy magnetic and induction mines with a small amount of technical means. However, it provided satisfactory protection only in the geomagnetic zone in which demagnetization was carried out. In other zones, the inductive magnetization changes in proportion to the change in the vertical component of the Earth's magnetic field, and the permanent magnetization changes slowly, over many months. Under the influence of various external factors, elastic stresses, stormy weather, deep-sea diving (for submarines), as well as close explosions of aerial bombs and other shaking, the permanent magnetization increases many times over.
In addition, it also depends on the prehistory, that is, on how much and how the ship was previously magnetized. Therefore, the results of studying the influence of these phenomena on the change in the magnetic fields of ships had to be strictly systematized.
For this purpose, the Criminal Code of the Navy developed special forms of protocols for windless demagnetization and control measurements of the magnetic fields of ships equipped with demagnetizers and equipment for their adjustment. In addition, forms of passports were developed that are issued to ships and filled in at the RRF during each next demagnetization. We received such documents from the flagship mechanic of the headquarters of the Black Sea Fleet on October 7, 1941.
The introduction of protocols and passports for the demagnetization of ships greatly facilitated the implementation of this process. It made it possible to accumulate experience in carrying out work, to study the influence of various factors on the change in the magnetic fields of ships, and, finally, was of great organizational importance. Ships that did not pass the next demagnetization within the prescribed period were not allowed to go to sea. And no one in the Black Sea Fleet violated this provision.
The operation to demagnetize the ships, according to the regulations, was carried out when the ship had already received the ammunition and all the cargo with which it would sail, i.e. it was the penultimate one (the last was the elimination of the deviation of the magnetic compasses) when preparing the ship for the campaign, and, as As a rule, there was very little time left for its implementation. This led to the fact that the demagnetization of the ship often had to be carried out at night, with complete blackout.
At the end of September 1941, by decision of the headquarters of the Black Sea Fleet, in the area of Troitskaya Bay, the Mine and Torpedo Department of the Black Sea Fleet equipped a test site, where, along with other devices, a contactor from a disarmed German magnetic mine was installed. The wires from it were brought ashore, to the laboratory. It became possible not only to check the quality of demagnetization of ships at this test site, but also to demonstrate it publicly. If the ship was demagnetized well, then when it passed along the stand above the contactor, no signals arose on the shore, and if the demagnetization was unsatisfactory, the contactor worked and a red lamp lit up on the shore, which was visible from the tested ship.
Navy sailors in general, and ship crews in particular, knew that magnetic mines for non-demagnetized ships posed a terrible threat. Evidence of this was not only reports in the press or in relevant documents, but also the explosions of non-demagnetized ships in the Black and Baltic Seas. Therefore, sailors took the degaussing of ships very seriously. The situation was aggravated by the fact that the crews of the ships themselves did not outwardly feel how qualitatively their ship was demagnetized. Sometimes the sailors called the actions of the "demagnetists" black magic. For the crew, the quality of the ship's degaussing is not an abstract interest, but a matter of life. It is possible that the fact that the immediate supervisors and participants in the work were not the usual factory engineers and craftsmen, but "pure scientists", physicists, had a certain influence on the increase in interest in the demagnetization of ships. Now no one is surprised by the joint work of scientists and engineers, this is considered not only normal, but in some cases the most effective, and then it was still unusual.
When checking the quality of the demagnetization of ships during their passage through the training ground, everyone who could only usually climbed onto the deck; they wanted to see with their own eyes whether the red lamp would light up or not. If the lamp did not light up, the tension among the people subsided, the mood rose and the ship went to the position. Otherwise, he returned to the SBR for the final degaussing. Such cases happened, but, fortunately, rarely.
The first quality check of the demagnetization of the S-33 submarine at the test site was carried out on September 24, 1941. It was successful. Then checks became more regular, and later mandatory.
During the period from August 25 to October 30, 1941 in Sevastopol, SBR-1 carried out 49 demagnetizations and control measurements of ships, mainly submarines, and five submarines were demagnetized at SBR-2 in Feodosia.
Due to the fact that there was no cable or production capacity for equipping even large auxiliary vessels with demagnetizing devices, at the suggestion of the LFTI team, some vessels that had large values of the longitudinal course difference of the magnetic field, for example, the Ostrovsky mine layer, the Lvov ambulance transport ", were subjected to combined demagnetization, in which the vertical magnetization of the ship's hull was eliminated by the windingless method, and the fields of the longitudinal course difference were compensated by the fields of temporary course windings laid along the upper deck at the ends of the ship.
It should be noted that by the time the SVR was organized, all regular officers and graduates of naval schools were already serving in full-time positions, and the reserve of officers of the naval crew consisted either of accidentally released regular officers, or (mostly) of reserve officers. Of these, we had to staff the SVR, and later the ship degaussing departments. Among the reserve officers, we sought to select engineers from large electrical plants and other enterprises who had good specialized training, extensive experience in practical work in the field of electrical engineering and experience in working with people. As it turned out later, such an approach in the conditions of that time was the most correct.
At various times, from the crew of the Black Sea Fleet, Mikhail Grigoryevich Vaisman was appointed to us - the former head of the design and technical department of KhEMZ, who headed the design of electrical equipment for ships under construction in the Navy, the author of the book "Ship Automation"; Alexander Ivanovich Borovikov - head of the design and engineering department of KhEMZ for the design of electrical equipment for submarines; Nikolai Alekseevich Biyatenko, about whom I wrote earlier; Mikhail Anatolyevich Obolensky - head of the design and engineering department of KhEMZ for the design of electrical equipment for rolling mills; Leonid Fedorovich Shibaev - chief power engineer of the Metallurgical Plant from Dnepropetrovsk; Yuri Vladimirovich Isakov - senior engineer of the design institute from Kharkov; Nikolai Ilyich Sarafanov - senior engineer of the design department of Electroprom from Odessa, etc. Of course, at first they lacked special naval training. They could not independently manage the ship during mooring, not to mention sea passages, but this was not the main thing: for these purposes, the SBR initially provided for the position of navigator. The main thing was to teach them how to demagnetize the ships well and organize their service in accordance with the ship charter of the Navy.
The work experience of subsequent years showed that the vast majority of them studied maritime affairs well, passed exams and received documents for the right to navigate. Many of them made independent sea crossings within the Black and Azov seas.
Here I want to dwell in more detail on one of our joint developments with M. G. Vaisman of that time - an automatic current regulator in the exchange rate windings of ship demagnetizers.
On destroyers of the "Bodry" and "Savvy" types, the leaders "Kharkov" and "Tashkent", the cruisers of the "Voroshilov" type and the battleship "Paris Commune", demagnetizing devices, in addition to the main windings, also had course windings - to compensate for the magnetic fields of the longitudinal course differences. Course horizontal windings were switched on at certain courses of the ship, that is, there was a two-stage, and later a three-stage reverse current regulation. Usually, a two-pole switch was installed in the navigational cabin of the ship, and from there, in accordance with the course of the ship, it was necessary to manually change the current in the course windings. The performance of this simple but mandatory operation, especially when maneuvering a ship at sea during enemy air raids or in mine-hazardous areas, required the allocation of a special person.
Mikhail Grigoryevich and I, accustomed to automating the designed shipboard electrical and mechanical devices, considered it necessary to automate this simple process by installing reversible two-pole contactors in the course winding circuit and sensors on the gyrocompass repeater located here, in the chart room. At that time, we already knew that ordinary contacts in the conditions of slow rotation of the gyrocompass repeater card, shaking and vibrations on the move of the ship would not provide reliable operation, so we decided to install "frog" contacts.
I remember it was a warm, cloudy Sunday. At that time, we were in the service around the clock (day and night in office premises). At about 3 pm, when most of the drawings had already been completed by me (before the war, I had worked for several years as a senior designer of electrical machines at KhEMZ), and Mikhail Grigorievich was drawing up a description of the device, enemy aircraft made a massive echeloned raid on ships stationed in Sevastopol bays.
The sky was covered with light cirrus clouds. High between them, groups of enemy aircraft of 9-12 pieces were clearly visible. They flew very high, and the fire of our anti-aircraft artillery was ineffective. Nevertheless, all naval and coastal anti-aircraft defenses fired intensely, preventing them from descending for targeted bombing or diving. One could see how the bombs sparkled in the sun at the moment of separation from the planes, their growing howl and the roar of explosions were heard, during which columns of water and silt rose from the seabed. Sometimes these pillars covered ships that were not far away from us, and we, with bated breath, waited in terrible excitement until the column of water subsided. Everyone thought: will we see them again or not? Our excitement is difficult to put into words. Here again, another series of bombs fell and exploded. Columns of water and mud that shot up blocked us from the cruiser Krasny Krym, which stood on barrels closer than other ships. The seconds seemed endlessly long until the veil fell. Finally the cruiser appeared, swaying slightly, with no signs of fire or direct hits from aerial bombs. So, whole!
After several visits, the enemy planes were driven off by our fighters and flew away. This time there were no direct hits.
For a long time we stood on the pier near the Mine Wall, discussing the events of the day. It was one of the last times we openly observed the bombings. Later, the enemy began to throw bombs and fire machine guns at people on the piers.
We sent our proposal to the Criminal Code of the Navy. Running a little ahead, I will say that it was approved. We made a prototype, which was tested by a commission chaired by a military engineer, II rank B. I. Kalganov. After that, the device was: installed on the battleship "Paris Commune" and operated on it until 1947, when it was: replaced by a new, more advanced automatic current regulator.
In the course of work on the demagnetization of ships, the peculiarities of the operation of magnetometers, which I have already written about, came to light.
The lack of instruments for the organized SBR-3 and the advantages of the "pistol" magnetometer prompted M. G. Vaisman and I to develop and manufacture a magnetometer of this type from domestic materials. It was not about the priority of development, but about ensuring the work of SBR-3, which at that time was more important.
The main element of this device was a metal piston made of "mu-metal" with a very high magnetic permeability and the absence of residual magnetization. We knew from the literature that Professor Meskin had developed an AlSiFe alloy with similar properties.
It was October 1941, and under military conditions, making new parts from precision magnetic alloys was not an easy task. However, thanks to the responsiveness of our people, we managed to solve this problem at the Sevastopol Marine Plant. When the blanks were cast, it turned out that in terms of their magnetic properties they met our requirements, but they had a coarse-grained structure, were hard and brittle. According to the operating conditions of the device, they should have had high processing accuracy, however, when trying to machine the workpieces on a lathe, it turned out that not a single cutter takes them, and they themselves crumble. But even here the masters of the Sevmorzavod came out of the situation: they processed them by grinding. Several of these pistons were made.
In the manufacture of other parts, we, guided by factory experience, sought not to develop new components or parts, but to make the most of existing products. So, a sleeve from a 76-mm artillery shell was used as a sealed cylinder made of non-ferromagnetic material for the sensor of the device. It was shortened to the required dimensions, a brass flange was welded to it.
As a result of tests carried out in Poti in the spring of 1942, it was found that our device is almost as good as the English one. The test report was sent to the Criminal Code of the Navy. Its main advantage was that on site it was possible to manufacture the required number of magnetometers from the available materials and ensure the operation of the SVR with them.
Quite recently, when looking through documents of the war years in the Central Archive of the Navy, I learned that we were not the only ones in the development and manufacture of magnetometers. The same devices were manufactured on the initiative of the Pacific Fleet Ship Demagnetization Service in June 1942 in the magnetism laboratory of the Institute of Metal Physics of the Ural Branch of the USSR Academy of Sciences in Sverdlovsk under the direction of I. K. Kikoin (later Academician).
From the book Technique and weapons 2002 03 authorOn the classification of automatic weapons (Continued. Beginning in "TiV" No. 10/2001, 1/2002).I.2. In systems with barrel recoil, the bolt is firmly engaged with the moving barrel during firing. Under the action of recoil, the barrel-bolt system begins to move backward, compressing the bolt spring and the spring
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From the book Technique and weapons 2002 09 author Magazine "Technique and weapons"On the classification of automatic weapons (Continued. Beginning in TiV No. 10/2001, 1, 3, 5, 7, B/2002). A variant of the cyclogram of the operation of automation with a short-stroke barrel recoil when fired from the rear sear of a single fire and using a roll-over accelerator. It was said above that when
From the book Technique and weapons 2002 10 author Magazine "Technique and weapons" From the book "Death to Spies!" [Military counterintelligence SMERSH during the Great Patriotic War] author Sever AlexanderChecks on the roads There are episodes in the history of the Great Patriotic War that official historians prefer not to remember. For example, the fact that in the summer of 1941 only one Abvergruppe-107 was able to capture about 20 official seals of the headquarters of various divisions, up to 40
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From the book Demagnetization of the ships of the Black Sea Fleet during the Great Patriotic War author Panchenko Victor DmitrievichEnemy air raid on Poti. Organization of the Ship Demagnetization Department On July 2, 1942, in Poti, at about 5 p.m., I finished work on the destroyer Bodry, which was stationed near the wall. He got off the ship ashore and began to transfer to the senior master of workshop No. 4 G.I.
From the book Battleships of the Royal Sovereign type author Fetter A. Yu.Increasing requirements for the quality of ship degaussing. Organization of new RRFs The work of the Ship Degaussing Department of the Black Sea Fleet in the second half of 1943 is characterized by a significant increase in the number of ships being processed and increased quality requirements
From the book All Messerschmitt's Aircraft Masterpieces. The Rise and Fall of the Luftwaffe author Antseliovich Leonid LipmanovichGatherings of specialists in the degaussing of ships. Further improvement of demagnetizing devices. Organization SBR-38. Electromagnetic minesweeper "Mina". Transition of SBR-3 from Batumi to Sevastopol
From the book Trajectory of Fate author Kalashnikov Mikhail TimofeevichRomanian port of Constanta. German fixed ship degaussing station. The results of the monthly trawling of the EMBTSCH "Mina". Trawling of the North Bay by a floating dock. An unusual way of trawling the Yalta fairway September 16, 1944 Head of the Technical Department
From the book Scouts and Spies author Zigunenko Stanislav NikolaevichDemagnetization of the battleship "Sevastopol" Shortly after the end of the war, the battleship "Sevastopol" was put in a major overhaul, during which it was planned to mount a new demagnetizer with laying all the winding cables inside the ship's hull. Project
From the book Battleships of the Queen Elizabeth type author Mikhailov Andrey AlexandrovichSeaworthiness Due to the length and contours, which were designed for greater speed than the low-sided "Trafalgar", the builders assumed that only 9000 hp. With. needed for 16 knots and 13,000 hp. With. with forced draft for 17.5. In fact, only "Royal Sovereign" developed this
From the author's bookThe Spanish training ground Hitler, in the presence of Goering, on July 25, 1936, agreed to the representative of General Franco to help transfer the rebellious troops of the Moroccan corps from North Africa to Seville. The next day, the first of twenty Yu-52s, led by Luftwaffe reservists,
From the author's book From the author's bookChecks from both sides Sorge really saw his main task in preventing a war between Japan and the USSR. And for this, first of all, it was necessary to be aware of the relations between Japan and Nazi Germany. What efforts were made by the Germans in relation to the Japanese,
From the author's bookAppendix No. 1 Damage to battleships of the 5th squadron in the battle of Jutland [* From the book of K.P. Puzyrevsky. Damage to ships from artillery and the struggle for survivability. Leningrad. Sudpromgiz. 1940] "Worspite". Belonged to the fifth squadron of battleships and was third in the convoy.
Ship degaussing artificial change in the magnetic field of the ship in order to reduce the likelihood of its detonation on magnetic and magnetic-induction mines. R. to. is achieved with the help of stationary demagnetizing devices (RU), the main element of which are special windings mounted directly on the ship and designed to compensate for its magnetic field. Ships and ships that do not have a switchgear undergo periodic demagnetization at stationary or mobile stations without winding demagnetization, where, after exposure to a demagnetizing external magnetic field, the ship's own magnetic field is reduced to the required level.
Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .
See what "Degaussing a ship" is in other dictionaries:
Reducing the strength of the ship's magnetic field to reduce the likelihood of it being blown up by magnetic and induction mines. There are two types of winding ship demagnetization (several cable cables are mounted on the ship in different planes ... ... Marine Dictionary
Ship degaussing- reducing the strength of the ship's magnetic field to reduce the likelihood of it being blown up by magnetic and induction mines. There are two types of R. to. winding (cable windings are mounted inside the ship's hull, through which a constant is passed ... ... Dictionary of military terms
Magnetization of ship iron under the influence of the Earth's magnetic field. Causes magnetic compass deviation. The magnetic and induction fuses of sea mines react to the magnetism of the ship. To reduce the magnetism of the ship, they use ... ... Marine Dictionary
Mine protection of the ship- a set of constructive measures and technical means that reduce the degree of destruction of the ship by mine weapons. Includes: structural protection of the ship; technical means to reduce the intensity of physical fields (noise reduction, ... ... Dictionary of military terms
mine defense- a set of measures to protect ships from being blown up by sea and river mines. The main means of P. o. minesweeping is used in combination with a number of auxiliary means. Of these, of particular importance are: observation organized on ... ... Brief dictionary of operational-tactical and general military terms
GOST 23612-79: Ship magnetism. Terms and Definitions- Terminology GOST 23612 79: Ship magnetism. Terms and definitions original document: 10. Deviation of the geomagnetic field on the ship Deviation E. Deviation F. Déviation D. Deviation Deviation of the elements of the magnetic induction vector on the ship from ... ... Dictionary-reference book of terms of normative and technical documentation
An electromagnet is usually used as a source of an alternating magnetic field. The decrease in the amplitude of the magnetic field acting on the demagnetized object can be achieved by reducing the amplitude of the current in the electromagnet, or, in simpler cases, by increasing the distance between the electromagnet and the object being demagnetized. Since the magnetic properties of materials disappear when heated above a certain temperature, in production, in special cases, demagnetization is carried out using heat treatment (see Curie point).
Applications
Electron ray tube (CRT) devices
The term was first used during the 2nd World War by the commander of the Canadian Naval Reserve Charles F. Goodive, who was trying to find protection against the German magnetic mines that caused serious damage to the British fleet.
Experiments to demagnetize ships during World War II may have given rise to the legend of the Philadelphia Experiment.
Elements of electromagnets
Electromagnets are used for electronic locks, relays, reed switches. In these devices, parts that were conceived by the developer as magnetically soft, that is, without their own magnetic induction in the absence of current in the coil, can become magnetized and render the device inoperative.
Tools and fixtures
When working with technological devices and tools, it is necessary that the material being processed, workpiece, part or product does not move after moving devices. This is especially true for handmade. For example, in many cases it is inconvenient to use a magnetized screwdriver, tweezers.
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Literature
- Tkachenko B. A. History of demagnetization of ships of the Soviet Navy / B. A. Tkachenko; USSR Academy of Sciences. . - L.: Science. Leningrad. department, 1981. - 224 p. - 10,000 copies.(in trans.)
Links
An excerpt characterizing Degaussing
- Give him some porridge; after all, it will not soon eat up from hunger.Again he was given porridge; and Morel, chuckling, set to work on the third bowler hat. Joyful smiles stood on all the faces of the young soldiers who looked at Morel. The old soldiers, who considered it indecent to engage in such trifles, lay on the other side of the fire, but occasionally, rising on their elbows, looked at Morel with a smile.
“People too,” said one of them, dodging in his overcoat. - And the wormwood grows on its root.
– Oo! Lord, Lord! How stellar, passion! To frost ... - And everything calmed down.
The stars, as if knowing that now no one would see them, played out in the black sky. Now flashing, now fading, now shuddering, they busily whispered among themselves about something joyful, but mysterious.
X
The French troops were gradually melting away in a mathematically correct progression. And that crossing over the Berezina, about which so much has been written, was only one of the intermediate steps in the destruction of the French army, and not at all the decisive episode of the campaign. If so much has been written and written about the Berezina, then on the part of the French this happened only because on the Berezinsky broken bridge, the disasters that the French army had previously suffered evenly, suddenly grouped here at one moment and into one tragic spectacle that everyone remembered. On the part of the Russians, they talked and wrote so much about the Berezina only because far from the theater of war, in St. Petersburg, a plan was drawn up (by Pfuel) to capture Napoleon in a strategic trap on the Berezina River. Everyone was convinced that everything would actually be exactly as planned, and therefore they insisted that it was the Berezinsky crossing that killed the French. In essence, the results of the Berezinsky crossing were much less disastrous for the French in the loss of guns and prisoners than the Red, as the figures show.
The only significance of the Berezina crossing lies in the fact that this crossing obviously and undoubtedly proved the falsity of all plans for cutting off and the validity of the only possible course of action required by both Kutuzov and all the troops (mass) - only following the enemy. The crowd of Frenchmen ran with an ever-increasing force of speed, with all their energy directed towards the goal. She ran like a wounded animal, and it was impossible for her to stand on the road. This was proved not so much by the arrangement of the crossing as by the movement on the bridges. When the bridges were broken through, unarmed soldiers, Muscovites, women with children, who were in the French convoy - everything, under the influence of inertia, did not give up, but ran forward into the boats, into the frozen water.
This endeavor was reasonable. The position of both the fleeing and the pursuing was equally bad. Staying with his own, each in distress hoped for the help of a comrade, for a certain place he occupied among his own. Having given himself over to the Russians, he was in the same position of distress, but he was placed on a lower level in the section of satisfying the needs of life. The French did not need to have correct information that half of the prisoners, with whom they did not know what to do, despite all the desire of the Russians to save them, were dying of cold and hunger; they felt that it could not be otherwise. The most compassionate Russian commanders and hunters of the French, the French in the Russian service could not do anything for the prisoners. The French were ruined by the disaster in which the Russian army was. It was impossible to take away bread and clothes from hungry, necessary soldiers, in order to give them not to harmful, not hated, not guilty, but simply unnecessary Frenchmen. Some did; but that was the only exception.
Behind was certain death; there was hope ahead. The ships were burned; there was no other salvation but a collective flight, and all the forces of the French were directed to this collective flight.
The farther the French fled, the more miserable their remnants were, especially after the Berezina, on which, as a result of the St. Petersburg plan, special hopes were placed, the more passions of the Russian commanders flared up, blaming each other and especially Kutuzov. Believing that the failure of the Berezinsky Petersburg plan would be attributed to him, dissatisfaction with him, contempt for him and teasing him were expressed more and more strongly. Joking and contempt, of course, was expressed in a respectful form, in a form in which Kutuzov could not even ask what and for what he was accused. He was not spoken seriously; reporting to him and asking his permission, they pretended to perform a sad ceremony, and behind his back they winked and tried to deceive him at every step.
All these people, precisely because they could not understand him, it was recognized that there was nothing to talk about with the old man; that he would never understand the full depth of their plans; that he would answer his phrases (it seemed to them that these were only phrases) about the golden bridge, that it was impossible to come abroad with a crowd of vagabonds, etc. They had already heard all this from him. And everything he said: for example, that you have to wait for provisions, that people are without boots, it was all so simple, and everything they offered was so complicated and clever that it was obvious to them that he was stupid and old, but they were not powerful, brilliant commanders.
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Introduction
1. The concept of constructive protection and physical fields of the ship
2. The main physical fields of the ship and ways to reduce them
3. Ship degaussing device
Conclusion
Introduction
physical field ship
In order to more successfully solve the ship's combat missions in the conditions of intensive development of detection and destruction means, it is necessary for all officers to know the physical fields of the ship and the World Ocean, ways to provide physical protection, be able to correctly use the technical means of protection and ship movement modes, and it is also necessary to serious attention to the choice of competent tactics to ensure the secrecy of the ship and reduce the likelihood of detection and destruction by non-contact weapons.
When designing and building ships of various classes, much attention is paid to ensuring their constructive protection from the effects of various types of weapons and guidance systems.
1. The concept of constructive protection and physicalfields toaboutslave
With the beginning of hostilities at sea, a confrontation began with weapons used to destroy ships and protect the ship from these weapons.
So in the period when the main weapon was a ram, they began to use armor on the sides of the ship. With the beginning of the use of artillery, considerable attention, along with armor, was paid to the fire protection of ships. During this period, the first fire-fighting systems appeared.
Reservation of ships, as the main type of protection, was widely used on ships until the beginning of the 20th century. During this period, there was a class of armored ships - battleships. In addition, other ships were also built using armor. The representative of these ships is the famous cruiser "AURORA" built during this period. The hull of this ship consists of two parts: a heavy armored underwater part and a light surface part.
With the increase in the power of artillery weapons and the advent of torpedo weapons, armor ceased to meet the requirements for ship protection. Therefore, the use of reservation has become inappropriate.
During this period, the rapid development of the basic provisions of the ship's survivability begins, the founder of which was the Russian officer, Admiral S.O. Makarov.
The application of the principle of dividing the ship into hermetic, watertight compartments, the widespread use of drainage and fire fighting equipment, emergency equipment and materials, as well as scientific approaches to the organization of damage control of the ship, all this allowed the ship to effectively withstand the combat effects of weapons of that time.
With the beginning of the use of proximity fuses and the emergence of homing systems, protection by physical fields became the main direction of ship protection. This type of protection is currently continuing to develop and improve, and with the advent of powerful missile weapons, the need to protect the ship has increased even more.
On modern ships, structural protection is provided by the following measures:
Giving the ship the necessary reserves of local and general strength;
Division of the ship into watertight compartments;
The use of technical means of combating water and fires;
Ensuring a decrease in the level of various physical fields.
Currently, various non-contact systems based on the principles of registering various physical fields of a ship are used to detect ships, classify them, track them, and destroy them. With the beginning of the use of proximity fuses and the emergence of homing systems, protection by physical fields became the main direction of ship protection.
physical field called a part of space or all of space, which has some physical properties. At each point of this space, some physical quantity has a certain value.
Fields, as peculiar forms of matter, include magnetic, thermal (infrared), light, gravitational and other fields.
Some physical fields are peculiar forms of motion of matter, such as an acoustic field. And some fields manifest themselves in the form of electromagnetic and gravitational phenomena in conjunction with the movement of matter, such as, for example, a hydrodynamic field.
Each place of the World Ocean has certain levels of physical fields - these are natural natural fields. Depending on the environment in which the physical fields of the ocean originate, they can be divided into:
1. Geophysical fields, due to the presence of the entire mass of the earth:
A magnetic field;
Gravity field;
Electric field; ocean relief field.
2. Hydrophysical fields, due to the presence of ocean water masses, which include:
Sea water temperature field;
Salinity field of sea water;
Sea water radioactivity field;
Hydrodynamic field;
hydroacoustic field;
Hydrooptical field;
the thermal radiation field of the ocean surface.
When creating technical means for detecting ships and non-contact weapon systems, the characteristics and parameters of the ocean fields are carefully taken into account, they are considered as natural interference, taking into account which the means must be configured in such a way as to highlight the physical field of the ship against the background of natural interference. On the other hand, ships can use ocean fields to mask or reduce the levels of their own fields.
A ship (SW), while in a given place of the oceans, makes changes to natural fields. It distorts (disturbs) one or another field of the World Ocean with a certain regularity, and in some cases it is itself exposed to physical fields, for example, it is magnetized.
The physical field of the ship called a region of space adjacent to the ship, within which a distortion of the corresponding field of the World Ocean is detected.
A surface ship is the source of various physical fields, which are the ship's characteristics that determine its stealth, protection, and combat stability.
The parameters of physical fields are widely used in the detection and classification of ships, in weapon guidance systems, as well as in control systems for non-contact mine-torpedo and missile weapons.
At present, a strict classification and terminology for the physical fields and wake of a ship has not yet been established. One of the options is the classification presented in table No. 1.
The physical fields of ships according to the location of the sources of the field are divided into primary ( own) and secondary (called out).
Primary (intrinsic) fields of ships are fields whose sources are located directly on the ship or in a relatively thin layer of water adjacent to its hull.
The secondary (evoked) field of the ship is the reflected (distorted) field of the ship, the sources of which are outside the ship (in space, on another ship, etc.).
Fields that are created artificially with the help of special devices (radio, sonar stations, optical instruments) are called active physical sex I mi.
The fields that are naturally created by the ship as a whole as a constructive structure are called passive physical fields of the ship .
According to the functional dependence of the parameters of physical fields on time, they can be divided into static and dynamic.
Static fields are such physical fields, the intensity (level or power) of the sources of which remains constant during the time of the impact of the fields on the non-contact system.
Dynamic (variable in time) physical fields are such fields, the intensity of the sources of which changes during the time of the field impact on the non-contact system.
The physical fields of the ship are currently widely used in three areas:
In non-contact systems of various types of weapons;
In detection and classification systems;
in homing systems.
The degree of use of physical fields in technical means of detecting, tracking ships and in non-contact weapon systems is not the same. At present, the following physical fields of a ship have found wide application in practice:
acoustic field,
thermal (infrared) field,
hydrodynamic field,
a magnetic field,
electric field.
The reasons for the occurrence and ways to reduce these physical fields of the ship will be considered in the following questions of the lesson.
2. The main physical fields of the ship and how to sleep themandzheniya
a) The acoustic field of the ship.
The acoustic field of a ship is a region of space in which acoustic waves are distributed, either generated by the ship itself or reflected from the ship.
Wave-like propagating oscillatory motion of particles of an elastic medium is commonly called sound.
The speed of sound propagation depends on the elastic properties of the medium (330 m/s in air, 1500 m/s in water, about 5000 m/s in steel). The speed of sound propagation in water also depends on its physical state, increasing with temperature, salinity and hydrostatic pressure.
A moving ship is a powerful source of sound that creates an acoustic field of great intensity in the water. This field is called the hydroacoustic field of the ship (HAPC).
In accordance with the classification discussed earlier, GAPC is divided into:
Primary HAPC (noise), which is formed by the ship's own source of acoustic waves;
Secondary HAPC (hydrolactation), which is formed as a result of acoustic waves reflected from the ship, emitted by an external source.
The hydroacoustic field (noise) of a ship is widely used in stationary, shipborne and aviation detection and classification systems, as well as homing systems and proximity fuses for mine and torpedo weapons.
The ship's hydroacoustic field is a combination of fields superimposed on each other, created by various sources, the main of which are:
Noises created by propellers (screws) during their rotation. The underwater noise of the ship from the work of the propellers is divided into the following components:
Noise propeller rotation,
swirling noise,
Vibration noise of the edges of the propeller blades ("singing"),
cavitation noise.
Noises emitted by the ship's hull on the move and in the parking lot as a result of its vibration from the operation of the mechanisms.
Noises created by the flow of water around the hull of the ship during its movement.
The levels of underwater noise depend on the speed of the ship and on the depth of immersion (for submarines). At travel speeds above the critical one, an area of intense noise generation begins.
During the operation of the ship, its noise can change for a number of reasons. So the increase in noise is facilitated by the development of the technical resource of ship mechanisms, which leads to their misalignment, imbalance and increased vibration. The oscillatory energy of the mechanisms causes hull vibrations, which leads to disturbances in the outboard environment, which determine underwater noise.
Vibrations of mechanisms are transmitted to the body:
Through the support links of the mechanisms with the body (foundations);
Through non-supporting connections of mechanisms with the body (pipelines, water pipes, cables);
Through the air in the compartments and rooms of the NK.
The pumps associated with the outboard medium transmit vibrational energy, in addition to the indicated paths, through the working medium of the pipeline directly into the water.
The noise level of a ship characterizes not only its concealment from hydroacoustic detection means and the degree of protection against mine-torpedo weapons of a potential enemy, but also determines the operating conditions of its own hydroacoustic detection and target designation means, interfering with the operation of these means.
Noise is of great importance for submarines (submarines), as it largely determines their stealth. Noise control and its reduction is the most important task of all ship personnel and especially submarines.
In order to ensure the acoustic protection of the ship, a number of organizational, technical and tactical measures are being taken.
These activities include the following:
improvement of vibroacoustic characteristics of mechanisms;
removal of mechanisms from the structures of the outer hull emitting underwater noise by installing them on decks, platforms and bulkheads;
vibration isolation of mechanisms and systems from the main body with the help of soundproof shock absorbers, flexible inserts, couplings, shock-absorbing pipeline hangers and special noise-protective foundations;
vibration damping and soundproofing of sound vibrations of foundation and hull structures, pipeline systems using soundproof and vibration-damping coatings;
sound insulation and sound absorption of airborne noise of mechanisms through the use of coatings, casings, screens, silencers in air ducts;
use of hydrodynamic noise silencers in seawater systems.
Cavitation noise is reduced by the following measures:
the use of low-noise propellers;
the use of low-speed propellers;
increase in the number of blades;
balancing propeller and shaft line.
The totality of constructive measures and actions of personnel aimed at reducing noise can significantly reduce the level of the ship's hydroacoustic field.
b) The thermal field of the ship.
The main sources of the ship's thermal field (infrared radiation) are:
Surfaces of the above-water part of the hull, superstructures, decks, casings of chimneys;
Surfaces of gas ducts and exhaust gas devices;
Gas torch;
Surfaces of ship structures (masts, antennas, decks, etc.) located in the zone of action of a gas torch, gas jets of rockets and aircraft during launch;
Burun and the wake of the ship.
Detection of surface ships and submarines by their thermal field, and the issuance of target designation to weapons is carried out using heat direction finding equipment. Such equipment is installed on aircraft, satellites, surface ships and submarines, coastal posts.
Thermal (infrared) homing devices are also supplied to various types of missiles and torpedoes. Modern thermal homing devices ensure the capture of targets at a distance of up to 30 km.
The most effective way to reduce the thermal field of the ship is to use technical means of thermal protection.
The technical means of thermal protection include:
exhaust gas coolers of a ship power plant (mixing chamber, outer casing, louvered air intake windows, nozzles, water injection systems, etc.);
heat recovery circuits (TUK) of the ship's power plant;
onboard (surface and underwater) and stern gas exhaust devices;
screens for infrared radiation from the internal and external surfaces of gas ducts (two-layer screens, profile screens with water or air cooling, shielding bodies, etc.);
universal water protection system;
coatings for the ship's hull and superstructures, including paintwork, with reduced emissivity;
thermal insulation of high-temperature ship premises.
The thermal visibility of a surface ship can also be reduced by tactical means. These methods include the following:
the use of masking effects of fog, rain and snow;
the use of objects and phenomena with powerful infrared radiation as a background;
the use of bow heading angles in relation to the carrier of the heat direction-finding equipment.
The thermal visibility of submarines decreases with increasing depth of their immersion.
c) The hydrodynamic field of the ship.
The ship's hydrodynamic field (HFC) is the area of space adjacent to the ship, in which a change in hydrostatic pressure is observed, caused by the movement of the ship.
According to the physical essence of the HIC, this is a perturbation by a moving ship of the natural hydrodynamic field of the World Ocean.
If in every place of the World Ocean the parameters of its hydrodynamic field are determined to the greatest extent by random phenomena, which are very difficult to take into account in advance, then a moving ship introduces not random, but quite natural changes in these parameters, which can be taken into account with the accuracy necessary for practice.
When a ship moves in water, fluid particles located at certain distances from its hull come into a state of perturbed motion. When these particles move, the value of the hydrostatic pressure changes at the place where the ship is moving, and a hydrodynamic field of the ship of certain parameters is formed.
When a submarine moves under water, the area of pressure change extends to the surface of the water in the same way as to the ground. If the movement is carried out at shallow depths of immersion, then a visually well-marked wave hydrodynamic trace appears on the surface of the water.
Thus, the hydrodynamic field of the ship is created when it moves relative to the surrounding fluid and depends on the displacement, main dimensions, hull shape, ship speed, and also on the depth of the sea (distance to the bottom of the ship).
The ship's hydrodynamic field (HFC) is widely used in non-contact hydrodynamic fuses for bottom mines.
It is very difficult to provide hydrodynamic protection for a ship of any type or significantly reduce the parameters of the GIC using structural means. To do this, it is necessary to create a complex shape of the hull, which will lead to an increase in resistance to movement. Therefore, the solution of the issue of hydrodynamic protection is carried out mainly by organizational measures.
To ensure the hydrodynamic protection of any ship, it is necessary and sufficient that the parameters of its GPC do not exceed the settings of a non-contact hydrodynamic fuse in magnitude.
Hydrodynamic field levels decrease as the ship's speed decreases. Reducing the speed of the ship to a safe one is the main way to protect ships from hydrodynamic mines.
The charts of safe ship speeds and the rules for using them are given in the instructions for choosing safe ship speeds when navigating in areas where hydrodynamic mines can be laid.
Along with the operational physical fields of the ship, there are also fields that depend almost exclusively on the physical and chemical properties of the materials from which the ship is built. Such physical fields of the ship include magnetic and electric fields.
d) The electric field of the ship.
The next physical field of the ship is the electric field. From the course of physics it is known that if an electric charge appears at any point in space, then an electric field arises around this charge.
The electric field of the ship (EPC) is the area of space in which direct electric currents flow.
The main reasons for the formation of the electric field of the ship are:
1. Electrochemical processes between parts made of dissimilar metals and located in the underwater part of the ship (propellers and shafts, steering gear, bottom-outboard fittings, hull tread and cathodic protection systems, etc.).
2. Processes caused by the phenomenon of electromagnetic induction, which consist in the fact that the ship's hull, during its movement, crosses the lines of force of the Earth's magnetic field, as a result of which electric currents arise in the ship's hull and nearby masses of water. Similarly, such currents appear in ship propellers during their rotation in the MPZ and MPK.
3. Processes associated with the leakage of currents of ship's electrical equipment to the ship's hull and into the water.
The main reason for the formation of EPC are electrochemical processes between dissimilar metals. About 99% of the maximum value of the EIC is accounted for by electrochemical processes. Therefore, to reduce the level of EPA seek to eliminate this cause.
The electric field of the ship significantly exceeds the natural electric field of the World Ocean, which makes it possible to use it to create non-contact naval weapons and means of detecting submarines.
In order to reduce the electric field of the ship, a number of measures are being taken, the main of which are the following:
The use of non-metallic materials for the manufacture of the body and parts washed by sea water;
Selection of metals according to the proximity of the values of their electrode potentials for the body and parts washed by sea water;
Shielding of EPA sources;
Disconnection of the internal electrical circuit of the EPC sources;
Coating EPC sources with electrically insulating materials.
G) The ship's magnetic field.
The ship's magnetic field (MPF) is a region of space in which the Earth's natural magnetic field is distorted by the presence or movement of a ship magnetized in the earth's field.
The ship's magnetic field (MPC) is widely used in proximity fuses for mine and torpedo weapons, as well as in stationary and aviation systems for magnetometric detection of submarines.
The reasons for the occurrence of the magnetic field of the ship are as follows. Any substance is always magnetic, i.e. changes its properties in a magnetic field, but the degree of change in properties is not the same for different substances.
There are weakly magnetic substances (for example, aluminum, copper, titanium, water), and strongly magnetic ones (such as iron, nickel, cobalt and some alloys). Substances that can be strongly magnetized are called ferromagnets.
To quantitatively characterize the magnetic field, a special physical quantity is used - the magnetic field strength H.
Another important physical quantity that primarily characterizes the magnetic properties of a material is the intensity of magnetization I. In addition, there are concepts residual magnetization and inductive namagnetization.
Remanent magnetization is the permanent magnetization of the ship, which remains unchanged for a sufficiently long period of time with a change or absence of EMF.
The inductive magnetization of a ship is a value that changes continuously and proportionally with a change in the EMF.
A ship, the hull of which is built of ferromagnetic material, or having other ferromagnetic masses (main engines, boilers, etc.) being in the Earth's magnetic field is magnetized, i.e. acquires its own magnetic field.
The magnetic field of the ship mainly depends on the magnetic properties of the materials from which the ship is built, construction technology, size and distribution of ferromagnetic masses, construction site and navigation areas, course, pitching and some other factors.
Ways to reduce the magnetic field of the ship will be considered in more detail in the next question of the lesson.
3. Degaussing device barkbla
The task of reducing the ship's magnetic field can be solved in two ways:
the use of low-magnetic materials in the design of the hull, equipment and mechanisms of the ship;
ship degaussing.
The use of low-magnetic and non-magnetic materials to create ship structures can significantly reduce the ship's magnetic field. Therefore, in the construction of special ships (minesweepers, minelayers), materials such as fiberglass, plastics, aluminum alloys, etc. are widely used. In the construction of some projects of nuclear submarines, titanium and its alloys are used, which, along with high strength, is a low-magnetic material.
However, the strength and other mechanical and economic characteristics of low-magnetic materials make it possible to use them in the construction of warships within limited limits.
In addition, even if the hull structures of ships are made of low-magnetic materials, then a number of ship mechanisms remain made of ferromagnetic metals, which also create a magnetic field. Therefore, at present, the main method of magnetic protection of most ships is their demagnetization.
Degaussing a ship is a set of measures aimed at artificially reducing the components of the strength of its magnetic field.
The main tasks of demagnetization are:
a) reduction of all components of the IPC tension to the limits established by special rules;
b) ensuring the stability of the demagnetized state of the ship.
One of the methods for solving these problems is winding demagnetization.
The essence of the method of winding demagnetization lies in the fact that the MPC is compensated by the magnetic field of the current of standard windings specially mounted on the ship.
The totality of the winding system, their power sources, as well as control and monitoring equipment is degaussing device(RU) ship.
The ship's switchgear winding system may include the following windings (depending on the type and class of the ship):
a) The main horizontal winding (MG), designed to compensate for the vertical component of the MPC. To demagnetize a larger mass of the ferromagnetic material of the casing, the exhaust gas is divided into tiers, with each tier consisting of several sections.
b) Heading frame winding (KSh), designed to compensate for the longitudinal inductive magnetization of the ship. It consists of a series of series-connected turns located in the frame planes.
a) The main horizontal winding of the exhaust gas.
b) Course frame winding KSh.
c) Course buttocks winding of the KB.
c) Course buttock winding (KB), designed to compensate for the field of inductive transverse magnetization of the ship. It is mounted in the form of several contours, located side by side in the buttocks planes, symmetrically with respect to the diametrical plane of the ship.
d) Permanent windings, used on ships of large displacement. These types of windings include a permanent frame winding (PN) and a constant buttock winding (PB). These windings are laid along the route of the KSh and KB windings and do not have any types of current regulation during operation.
e) Special windings (CO) designed to compensate for magnetic fields from individual large ferromagnetic masses and powerful electrical installations (containers with missiles, minesweeping units, batteries, etc.)
The power supply of the switchgear windings is carried out only by direct current from special power supply units of the switchgear. The power supply units of the switchgear are electric machine converters, consisting of an AC drive motor and a DC generator.
To power converters and switchgear windings on ships, special switchgear power boards are installed, which receive power from two current sources located on different sides. The necessary switching, protective, measuring and signaling equipment is installed on the switchgear boards.
For automatic control of currents in the RU windings, special equipment is installed, which regulates the currents in the RU windings depending on the magnetic course of the ship. Currently, ships use current regulators of the KADR-M and CADMIY types.
Along with winding demagnetization, i.e. using RU, surface ships and submarines are periodically subjected to windless demagnetization.
The essence of windless demagnetization lies in the fact that the ship is subjected to short-term exposure to strong, artificially created magnetic fields, which reduce the IPC to certain standards. The ship itself does not have any stationary demagnetizing windings with this method. Windingless demagnetization is carried out on special SBR stands (windingless demagnetization stand).
The main disadvantages of the windingless demagnetization method are the insufficient stability of the ship's demagnetized state, the impossibility of compensating the inductive components of the MPC, which depend on the course, and the duration of the windingless demagnetization process.
Thus, the maximum reduction of the ship's magnetic field is achieved by applying two methods of demagnetization - winding and non-winding. The use of RI makes it possible to compensate for the MPC during operation, but since the ship's magnetic field can change significantly over time, the ships need periodic magnetic treatment at the SBR. In addition, the SBR measures the magnitude of the ship's magnetic field in order to maintain the IPC within the established aisles.
Conclusion
Thus, the considered physical fields of the ship are directly related to its operation. Various systems for detecting ships and submarines, weapon guidance systems, as well as proximity fuses for mine and torpedo weapons are based on the use of these physical fields.
In this regard, reducing the levels of the physical fields of the ship and maintaining them within acceptable limits is an important task for the entire crew of the ship.
The detection of a ship by any means of observation, as well as the operation of non-contact homing systems and weapon fuses, occurs when the intensity of the ship's field exceeds the sensitivity threshold of these means.
There are several fundamentally different ways to reduce the probability of detection and destruction of ships by combat means and non-contact systems. Their essence is as follows:
1. Use the camouflage features of the fields of the World Ocean, features of the water or air environment, tactical methods in such a way that, if possible, observing the enemy, ensure your own stealth at a certain distance and the lowest probability of being hit by non-contact weapons.
2. Reduce the intensity of the ship's physical field sources with the help of constructive and organizational measures. This method is called ensuring the physical protection of the ship.
The protection of the ship from the detection and impact of various types of weapons to a large extent affect the combat capability of the ship and the effective performance of the tasks facing the ship. The better the ship is protected, the less likely it is to receive various damages.
If the ship still receives damage from the impact of enemy weapons (or emergency damage), then it must be able to withstand these damage and restore its combat capability. This quality is the survivability of the ship.
This quality will be discussed in the next lesson.
Educational and methodological support
1. Visual aids: stand "Longitudinal section of the ship",
Device URT-850.
2. Technical Teaching Tools: overhead projector.
3. Application: overhead slides.
Literature
1. UE "Physical fields of the ship" Inv. No. 210
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