Ship's fire system. Ship's water fire extinguishing system

The vessel is closed system, which is subject to increased requirements in terms of fire safety. Regardless of the type, purpose, navigation area, engine type, hull/superstructure materials and other parameters, water transport must have effective fire extinguishing equipment. This will ensure the safety of personnel/passengers and minimize damage in the event of an emergency.

Fire extinguishing system on the ship designed taking into account possible reasons fire - from the design features of the ship to the nature of the cargo being transported and the human factor. The most effective are automated systems, providing volumetric spraying of fire extinguishing agent (water, steam, foam, aerosol) on open and hidden paths of flame propagation.

Ship fire extinguishing systems: basic requirements

According to the standards of the Russian River and Sea Register of Shipping, volumetric fire extinguishing systems on passenger and cargo ships of the river/sea fleet, as well as on tugboats and other types of water transport, must provide effective fire protection for such objects as:

• engine rooms, boiler rooms, generator rooms, pump rooms, distribution boards;
• ventilation systems in rooms for mechanical and electrical equipment;
• cofferdams and compartments for tanks for fuel, oil, and subsoil water collection;
• storerooms for storing flammable liquids and gases;
• premises general purpose(for passengers and staff).

IN Lately To ensure the safety of ships, aerosol fire extinguishing installations are increasingly being used, which is due to their advantages over other types of fire extinguishing equipment.

Features of aerosol volumetric fire extinguishing

The aerosol fire extinguishing system includes fire extinguishing aerosol generators (FAG), sensors (smoke, fire, temperature), autostart units, and light and sound alarms. When signs of fire are detected, generators are started, which emit a cloud of gas-aerosol mixture into the room. The composition quickly extinguishes the flame and maintains the extinguishing concentration for a long time, eliminating the possibility of re-ignition.

Advantages of aerosol fire extinguishing for water transport

• High fire-fighting efficiency- the modular system covers all compartments of the vessel, generators are selected according to the size of the room (the protected volume depends on the model and ranges from 2.2-134 m3).
• Excellent performance- after installation, the generators do not require periodic recharging, the operating temperatures of the modules vary in the range of +/-50 °C, and operate uninterruptedly in facilities with humidity levels up to 98%.
• Economic efficiency- aerosol installations have the lowest price among all types of fire extinguishing equipment; they do not require maintenance costs and the arrangement of a separate room for a fire extinguishing station.
• Easy installation- laying of cables for system automation is carried out along existing routes; generators do not need to be connected to engineering networks, so work can be carried out without taking the vessel out of service.
• Environmental friendliness- the aerosol mixture does not contain toxins or aggressive chemicals, does not cause significant harm to people and does not damage expensive ship units and electrical equipment.

JSC NPG Granit-Salamandra is the world's leading manufacturer of aerosol fire extinguishing systems. We provide a full range of services - from the sale of equipment to the development of design solutions and professional installation of aerosol fire extinguishing systems on any vessels.

Fire extinguishing systems on a ship are the ship's structures. When designing them, many factors are taken into account: the autonomy of the vessel, the presence of flammable materials in the design, placement of rooms with different levels fire danger, restrictions on the width of escape routes.

All of the above factors only aggravate the fire hazard of watercraft, according to this implementation in various ways ensuring the safety of passengers, as well as the development of new, more efficient ones, is given special attention.

Types of ship fire extinguishing systems

Stationary fire extinguishing systems on a ship are developed during the design of the ship and installed during its laying. Modern ships of the Russian merchant fleet are equipped with the following installations:

• • Sprinklers with manual or automatic activation;
  • Water curtains;
  • Water spray or irrigation;
• Gas - based on carbon dioxide or inert gases;
• Powder.

In some cases, the quality used in the same systems is medium and high density foam.

Each of fire extinguishing systems on board used to solve a specific, narrowly focused problem:

• Water - used to protect public and residential premises of the ship and its corridors, as well as premises where solid flammable and combustible substances are stored;
• Foam - installed in rooms where class B fires may occur;
• Gas and powder - used for class C fire protection.

Aerosol volumetric fire extinguishing system (AOT)

It is installed mainly on passenger vessels of the river fleet.

It is located in the following places:

• Engine room, main and auxiliary engines that run on liquid fuel;
• In the premises of boilers and generators of main and emergency sources of electricity;
• In places where main energy lines and distribution panels branch;
• In places where electric motors are installed, both auxiliary and main – propeller motors;
• In equipment ventilation networks.

All main workers must comply with the requirements of the technical regulations in accordance with which the classification and construction of ships is carried out. Presented equipment automatic fire extinguishing volumetric type was developed by the Flame laboratory at the Naval Engineering Institute.

Working fire extinguishing devices are autonomous modules TOP-1500 and TOP-3000 connected to a unified external control and warning network. Each module is a cylinder with a fire extinguishing agent with an optical-electronic combustion detector built into it.

Checking incoming information using several parameters significantly reduces the risk of false positives.

The cylinders are connected to the central apparatus and can be activated manually at the command of the captain or duty officer from the ship's control room.

Tests conducted in 2011 showed high efficiency installed system. She is able to extinguish burning and. In particular, during the tests, a smoldering tree was extinguished, and a pan with burning diesel fuel was extinguished.

Ship water system is installed when it is laid. It can be of two types - circular and linear. The main pipes through which water flows have a diameter of up to 150 mm, and working pipes up to 64 mm. This diameter should provide a water pressure at the furthest connection point on the ship, 350 kPa on cargo ships and 520 kPa.

Sections of the pipeline that are exposed to the external environment and may freeze are subject to piping using a drain and shut-off valve, so that if they are excluded from the general system, it continues to function. The distance between fire hydrants varies. Inside the vessel it is up to 20 m when equipped with 10-15 m of fire hoses. On deck, the range can be up to 40 m when each crane is equipped with a 15-20 m hose.

The living compartments are equipped with sprinkler systems equipped with fusible link nozzles with a maximum destruction temperature of 60°C. The device consists of pipeline sprayers (sprinklers) and a pneumohydraulic tank under pressure. The minimum performance of one sprinkler, regulated by regulations, is 5 liters per 1 m 2 of cabin.

Deluge systems are mainly used on cargo ships: gas carriers, tankers, bulk carriers and container ships, where cargo is placed horizontally. The main design feature is the presence of a pump, which, when an alarm is triggered, begins to draw water and supply it to the deluge pipeline. Deluge for forming water curtains in those areas of the ship where it is impossible to install fire barriers.

Gas fire extinguishing systems on ships

Gas fire extinguishing system on a ship Used exclusively in cargo compartments and in the auxiliary generator and pump rooms in the galley. In the engine compartment, both locally and locally, with the volumetric jet directed directly to the generators. Its high efficiency is combined with the equally high cost of maintaining the system itself and the need to periodically replace the fire extinguishing agent.

Recently, ships have begun to stop using carbon dioxide as a fire extinguishing agent. Instead, it is preferable to use an agent from the freon family. The type of control systems for a gas fire extinguishing installation depends on the operating pressure in the pipelines:

• For devices with low pressure, starting and adjusting the flow intensity is carried out manually;
• For medium pressure systems, redundant fire extinguishing control devices are provided.

Unlike buildings and structures, ships are constantly being improved and the use of old rules for installing fire extinguishing devices is often ineffective. Typical calculations for systems are used very rarely and only for small mass-produced vessels.

According to the latest statistics in the world, about 20% of destroyed ships are victims of fires. In Russia only in the Northwestern Federal District from 2008 to 2012, 82 fires on river and sea vessels had to be extinguished. Most of these fires occurred at docks and parking lots.

Why do fires happen on ships? After all, next to the fire, literally a few meters away, there is an inexhaustible natural source of water. It would seem, take this water and put out the fire. However, not everything is as simple as it seems at first glance. There are two factors at play here that block this simple solution.

The first factor is the speed of spread.

A fire on a ship spreads like lightning due to design features ships: low ceilings, narrow passages, metal partitions that easily allow temperature to pass into adjacent compartments, ventilation hatches and shafts, hollow structures with flammable heat-insulating filler, highly flammable paint and varnish coatings and Decoration Materials, - all this leads to the fact that the fire quickly gains strength in 10 - 15 minutes and covers hundreds of square meters, and in 30 minutes it covers all floors of a multi-deck ship. To fight such a fire, tons and tons of water or foam will be required.

The second factor is loss of buoyancy.

The use of water leads to rapid filling of the hold, a gradual list and, as a result, to the complete sinking to the bottom of all the property that we were so actively trying to save. When using water, it is necessary to constantly pump it out, which greatly complicates the task, and in many situations is simply technically impossible.

Based on the foregoing, we can conclude: water transport needs new approaches and new, more acceptable and effective technologies in fire extinguishing. One of such solutions is the use of volumetric aerosol extinguishing (AEF) on ships.

Ship fire protection systems AOT are an effective way to protect Navy and River Fleet vessels from fires.

The ship's AOT aerosol volume extinguishing system was developed by MPPA "EPOTOS" and certified for the protection of river and sea vessels. The fire protection system of a ship is installed on passenger ships of the river or sea fleet, tugboats, cargo tankers and serves to protect:

• main and auxiliary engines, engine rooms;
• electricity generators running on combustible fuel;
• fire pump rooms;
• distribution boards (main and emergency);
• electric motors for various purposes(including rowing engines);
• ventilation systems for ship equipment;
• rooms with tanks of fuel, various oils and lubricants, collection of subsoil waters, cofferdams;
• premises for storing liquefied or compressed gases, other flammable materials or substances.

AOT system. Testing and certification.

The fire-fighting ship system is certified and complies with the Technical Regulations “On the Safety of Inland Water Transport and Related Infrastructure”, the Technical Regulations “On the Safety of Maritime Transport Facilities”, the Rules for the Classification and Construction of Sea Vessels, as well as the Rules for the Classification and Construction of Inland Navigation Vessels.

Elements of the ship's AOT fire protection system have been tested and certified by the Russian Maritime Register of Shipping (RMRS), the Russian River Register (RRR). The fire extinguishing aerosol generators "TOR - 1500" and "TOR - 3000", which are the executive elements of the system, comply with international requirements and standards for ship fire fighting systems based on condensed fire extinguishing aerosol - ISO 15779:2011 and MSC.1/Circ.1270 (IMO) .

In particular, the fire extinguishing aerosol generators included in the system have passed certification tests for corrosion, impact deformation (fall from a height of 2 m onto a rigid base and on a pile driver - 1000g), vibration with a frequency range of 10 - 150 Hz and a maximum amplitude of vibration acceleration of 29 ,43 m/sec, temperature check (heating 250 Cº for 10 minutes).

Full-scale fire tests of the AOT system (for compliance with the specifications and circular IMO MSC 1/Circ/1270 dated 06/04/08) were carried out in June 2011 in the testing center of the “Plamya” laboratory of the Naval Engineering Institute (GOU VPO) of the Russian Defense Ministry in the city Pushkin - 4. For remote control of the ship's fire protection system, a certified BUS control and alarm unit was used own production, which is part of the AOT system.

During fire tests of the system, model fires of class A and B were extinguished: smoldering materials (wood), diesel fuel in metal pallets (including a jet of diesel fuel under low pressure with low flow rate). The high fire extinguishing ability of the ship's fire extinguishing system AOT was confirmed by full-scale tests in South Korea for compliance with ISO 15779:2011 and MSC.1/Circ.1270(IMO), which were carried out at the testing center of Koryo Pyrotechnics Co.Ltd. Based on the test data, the company received a Certificate from the Greek Maritime Register.

Class A: Hard Materials

Class B: Flammable liquids

Class C: Combustion of gases, incl. liquefied

Class D: Alkali metals (sodium, lithium, calcium, etc.)

Class E: Live electrical appliances and wiring.

Class "A" fires - combustion of solid combustible materials. To such materials

include wood and wood products, fabrics, paper, rubber, some plastics and

These materials are extinguished mainly with water, aqueous solutions, and foam.

Class "B" fires - combustion of liquid substances, their mixtures and compounds. To this class

substances include oil and liquid petroleum products, fats, paints, solvents and others

flammable liquids.

Such fires are extinguished mainly using foam by covering it

surface layer flammable liquid, thus separating it from the combustion zone and

oxidizer. In addition, Class B fires can be extinguished with water spray,

powders, carbon dioxide.

Class "C" fires - combustion of gaseous substances and materials. To this class

substances include flammable gases used on sea vessels as

technological supply, as well as flammable gases transported by sea vessels in

as cargo (methane, hydrogen, ammonia, etc.). Extinguishing flammable gases is carried out

compact jets of water or using fire extinguishing powders.

Class "D" fires - fires involving alkali and similar metals and their

compounds upon contact with water. These substances include sodium, potassium,

magnesium, titanium, aluminum, etc. To extinguish such fires they use

heat-absorbing fire extinguishing agents, such as some powders, are not

reacting with burning materials.

Class "E" fires - combustion that occurs when a substance under fire is ignited

voltage of electrical equipment, conductors or electrical installations.

Sprinkler systems (Fire detection function).

An automatic fire sprinkler and fire detection alarm system is installed on the ship so as to protect living spaces, galleys and other service spaces, with the exception of spaces that do not pose a significant fire hazard (empty spaces, sanitary spaces, etc.).

The sprinkler system consists of a water tank to power the system, a pump and a system

pipelines. The system ensures constant water pressure in the pipelines. From the main pipeline there are branches to all rooms protected by the system, equipped with spray heads. The spray heads are equipped with glass guards filled with liquid. These fuses are designed for a certain temperature, at which they burst and open a hole to spray water into the room.

Since the pipelines are under pressure, water begins to spray, forming

a vapor curtain capable of extinguishing the flame.

The sprinkler system is divided into sections of the vessel's cover. Each section has its own control station, including shutoff valves. When the spray head is triggered in a certain section, the pressure sensor detects the resulting pressure difference and sends a signal to the central display panel, which is located on the Bridge.

A typical indicator panel provides an audible and visual signal (siren and indicator light). The light indicates in which section of the vessel the system has tripped and the type of alarm (pressure drop in the system as a result of the spray head being triggered or the water supply to the section being cut off by the system's isolation valve).

When the fresh water in the system tank is completely consumed, the automatic use of sea water is provided. Typically, a sprinkler system is used as the initial automatic means of extinguishing

fire before the arrival of the ship's fire brigades. Usage sea ​​water in system

is not advisable and, if possible, the section should be insulated in a timely manner to stop the flow of fresh water. Arriving firefighters will continue to fight the fire using other available means.

If seawater is used in the system, the entire piping system must be thoroughly flushed with fresh water. Exploded spray heads must be replaced with spare ones (the necessary supply of which must always be on board).

The ship's main fire system. Fire main system

Such a system on a ship is a seawater fire extinguishing system, consisting of fire pumps and pipelines, fire hydrants and hoses with adjustable nozzles.

The system is designed to use seawater as a fire extinguishing agent, using the cooling effect (eliminating the Heat element in the Fire Triangle).

Foam generators that produce high-expansion foam can be connected to the water extinguishing system.

The system consists of fire pumps and pipelines, fire hydrants and hoses with

adjustable nozzles. It covers the entire space of the ship, all passages, rooms, including engine rooms, open decks.

The diameter of the fire main and its branches must be sufficient for efficient distribution of water with the maximum required supply of two simultaneously working

fire pumps; however, on cargo ships it is sufficient that such a diameter provides a supply of only 140 cubic meters / h.

The maximum pressure in any valve should not exceed the pressure at which the fire hose can be operated effectively.

Each fire pump must supply at least two jets of water at the required pressure to fight a fire.

The pump capacity must be at least 40% of the total capacity of fire pumps and in any case not less than 25 cubic meters / hour.

On a cargo ship it is not necessary for the total required fire pump capacity to exceed 180 m/h.

Ships must be equipped with fire pumps with independent drives

the following quantity:

On passenger ships of 4,000 gross tonnage or more: at least 3 pumps;

On passenger ships of less than 4,000 gross tonnage and on cargo ships of 1,000 gross tonnage or more: at least 2;

On tankers, in order to preserve the integrity of the fire main in the event of a fire or explosion, isolating valves must be installed on it in the bow in a protected place and on the deck of cargo tanks at intervals of no more than 40 m.

The number and placement of taps (hydrants) must be such that at least two jets of water from different taps, one of which is supplied through a solid hose, reach any part of the vessel, as well as any part of any empty cargo space, any cargo space with horizontal method of loading and unloading or any room of a special category, and in the latter case two jets must reach any part of it,

served in one-piece sleeves. In addition, such taps should be located at the entrances to the protected premises.

Pipelines and taps must be located so that they can be easily accessed

attach fire hoses.

A valve is provided to service each fire hose so that any fire hose can be disconnected while the fire pumps are running.

Isolation valves for disconnecting a section of the fire main located in

machine room in which the main fire pump or pumps are located, the rest of the fire main is installed in an easily accessible and convenient location outside the machinery spaces.

The location of the fire main shall be such that, with the isolating valves closed, all the ship's valves, except those located in the above-mentioned machinery space, can be supplied with water from a fire pump located outside that machinery space through pipes passing outside it.

International Maritime Union. International Shore Connection

Any ship over 500 tons must have at least one International Maritime Connection to be able to connect to the fire main from another ship or from shore.

Connections for such a connection must be provided on the forecastle and stern of the vessel.

Carbon dioxide extinguishing systems

For cargo spaces, the amount of carbon dioxide available must be sufficient to produce a minimum volume of free gas equal to 30% of the gross volume of the largest cargo space of the ship protected by the system.

For machinery spaces, the quantity of carbon dioxide available must be sufficient to produce a minimum volume of free gas equal to the greater of the following:

40% of the gross volume of the largest machinery space so protected, excluding the volume of part of the shaft, or 35% of the gross volume of the largest machinery space protected, including the shaft.

However, for cargo ships of less than 2,000 gross tonnage, the percentages given may be reduced to 35 and 30% respectively; in addition, if two or more machinery spaces are not completely separated from each other, they are considered to form one space. In this case, the volume of free carbon dioxide should be determined at the rate of 0.56 m^3/kg.

The fixed piping system for machinery spaces must ensure that 85% of the gas is supplied to the space within 2 minutes.

Carbon dioxide systems must meet the following requirements:

Two separate means must be provided to control the supply of carbon dioxide to the protected space and to provide an alarm for the release of gas. One should be used to release gas from gas storage tanks. The other must be used to open the valve on the pipeline supplying gas to the protected area;

These two controls must be located inside a cabinet that is easily identifiable to

specific protected premises. If the control cabinet is locked, the cabinet key must be in a case with a breakable lid in a visible location near the cabinet.

Steam fire extinguishing systems

As a general rule, the use of steam as an extinguishing agent in fixed fire extinguishing systems should not be permitted. If the use of steam is permitted by the Administration, it must be used only in limited areas in addition to the required fire extinguishing agent, and the steam capacity of the boiler or boilers providing steam must be at least 1.0 kg per hour for every 0.75 m of gross volume of the largest from the premises thus protected.

Stationary high-expansion FOAM fire extinguishing systems in engine rooms

premises.

1. Any stationary fire extinguishing system with high-expansion foam in engine rooms

premises must ensure rapid supply through fixed outlets of an amount of foam sufficient to fill the largest protected space, with an intensity that ensures the formation of a layer of foam at least 1 m thick in one minute. The amount of foam concentrate available must be sufficient to produce foam in a volume equal to five times the volume the largest protected space. The foaming ratio should not exceed 1000:1.

2. Foam supply channels, foam generator air intakes and the number of foam generators

installations must ensure efficient production and distribution of foam.

3. The location of the foam generator outlet channels must be such that a fire in

protected area could not damage the foam-forming equipment.

4. The foam generator, its energy sources, foam concentrate and system controls must be easily accessible, simple to operate and concentrated in as few locations as possible that are not likely to be cut off by a fire in the protected area.

Foam concentrate is a thick liquid. To form foam, it is diluted with water in ratios between 1 and 6%, depending on the type of concentrate.

The most commonly used foam in foam extinguishing installations is AFFF (Aqueous Film Forming Foam).

This foam, in addition to the effect of blocking the access of oxygen to combustion, covers the surface of the fuel with a film of water, preventing the formation of vapors. Such foam puts out the flame very quickly. It penetrates deeper into materials better when extinguishing Class A fires.

TSPOGneTatwAndTelI	CVeT	ClAWithWith POandmacaw	LathweeetcAndmenenAnde
INodA	TOraWithny		When burning solid materials
PenA	TOremnew	A, B	Better when extinguishing burning liquids (petroleum products, flammable liquids, paints and varnishes).
PorowOK	GolatbOuch	A, B, C,E
CO 2 (AngleeTowiryGaz)	Hernsth	A, B, C,E	It is better when extinguishing live electrical appliances and electrical wiring; it is used for all types of fire.

A fire on a ship is one of the most dangerous disasters. It causes much more destruction than any other type of accident. In the event of a fire, cargo can deteriorate, machinery and ship equipment may fail, and it poses a threat to human life. Fires on passenger, cargo and passenger ships and tankers cause especially great damage. In the latter, they may be accompanied by an explosion of oil vapors in cargo tanks. A fire can occur due to faulty electrical wiring, improper operation of electrical and heat exchange equipment, careless and careless handling of fire, sparks hitting flammable materials, etc.

Constructive fire prevention measures in accordance with the requirements of the Maritime Register and SOLAS - 74 are provided during the design process of the vessel. These include dividing the ship with fire-resistant transverse bulkheads, using non-combustible materials for finishing the premises, impregnating wooden products with fire-resistant compounds, preventing sparks in compartments and rooms where flammable explosive liquids or materials are stored, providing the ship with fire-fighting equipment and inventory, etc.

But preventive measures alone cannot prevent fires on ships. Fire fighting is carried out using various means that can localize a fire, stop its spread, and create a combustion-resistant atmosphere around the fire source. Seawater, water vapor, carbon dioxide, foam and special fire extinguishing liquids, the so-called freons, are used as such means. Fire extinguishing agents are supplied to the fire source by fire extinguishing systems: water, water spray and irrigation, steam extinguishing, carbon dioxide and foam fire extinguishing, volumetric chemical extinguishing, inert gases.

In addition to stationary fire extinguishing systems, ships are equipped with medium expansion foam apparatus, portable foam installations, manual and foam carbon dioxide fire extinguishers.

Fire protection systems also include fire alarm systems (manual, semi-automatic and automatic), which provide preventive fire prevention measures.

Fire alarm. Designed to detect a fire at the very beginning of its occurrence. Fire alarms are especially necessary in rooms where there are almost no people (cargo holds, storerooms, painting rooms, etc.). The fire alarm system includes devices, instruments and equipment that are used to automatically transmit signals about

fire on the ship; warning alarm- notifying the crew and production personnel about the activation of one of the volumetric fire extinguishing systems. The ship's fire alarm system also includes manual fire alarm devices, which allow the person who discovers a fire to immediately report it to the control center; emergency alarm (loud bells, howlers, etc.), designed to inform all ship personnel about the occurrence of a fire

The signal sent by an automatic or manual fire alarm goes to a special panel at the corresponding post and is recorded on it. An alarm signal to personnel (alert alarm) can be given from the post manually or automatically. Machinery, boiler and pump rooms, as well as other fire-hazardous places must be equipped with automatic fire alarms. Manual fire alarm sensors are installed in the corridors and lobbies of residential, office and public premises.

Most often, on ships, the alarm system provided for by the Register Rules is used, with detectors that respond to temperature environment. In Fig. 34 shows a schematic diagram of a fire alarm device

Alarm device 2 is installed in a protected area. 1 and 10 batteries included in electrical network. Thanks to the presence of significant electrical resistance 4, the current passes mainly through the circuit with the detector, so the current strength in the branches is insufficient to operate the fire gong 6, signal bell 8 and red lamps 5 and 9. When the signaling device opens the electrical circuit, solenoids 5, 7 and // close the contacts of the branches (solenoid 3 bypasses resistance 4) and electricity enters the signal network, activating the corresponding devices located in the control center. Each lit red lamp corresponds to its own number of the protected premises.

The designs of some signaling devices are shown in Fig. 35. The simplest maximum temperature detector (Fig. 35, a) is mercury thermometer with soldered platinum contacts. When the temperature rises to a certain value, the mercury column expands, reaches the upper contact and closes the electrical circuit. The maximum thermostatic type detector is shown in Fig. 35, b.

A bimetallic strip is used as a sensitive element 2, mounted on a porcelain or plastic base 1. The top layer of the plate is made of a material with a low coefficient of linear expansion, and the bottom layer is made of a material with a large coefficient. Therefore, as the temperature increases, the plate bends down. When the temperature reaches the specified limit value, the movable contact 3 will come into contact with the stationary 4 and closes the circuit. Contact 4 made in the form of an adjusting screw with an adjustment scale on the disk. Using the screw, you can adjust the detector in the range from 303 to 343 K (30 to 70 ° C).

The most common is a differential temperature detector (Fig. 35, V).

The internal cavity of its body is divided by a membrane 3 for two cameras. Upper chamber 4 communicates with the room, and the lower / (with blank walls) is connected to it through a sleeve 2 with several holes of very small diameter. The rod is fixed to the bushing 7, which rests on the moving contact 6. Screw 5 serves as a stop that limits the movement of the movable contact.

At a constant air temperature in the controlled room, the pressure in both chambers is the same and the contact 6 closed with fixed contact. If the air temperature in the room increases rapidly, the air in the detector body heats up. From the upper chamber 4 it can freely exit through the channels in the walls of the housing. The exit of air from the chamber 1 only possible through small diameter holes in the bushing 2. Therefore, a pressure difference arises, under the influence of which the membrane 3 the rod bends upward and 7 moves the contact 6 - the circuit opens, causing an impulse to be sent to the alarm system. If the room air temperature changes at a low speed, the air from the chamber 1 manages to flow out of the bushing hole 2 and the contacts do not open.

Except electrical system alarm systems on ships use fire-fighting smoke systems based on smoke control -

air using the fire alarm signal apparatus. In this case, the fire danger signal is given by the air itself, sucked from the room into the signaling apparatus.

Water fire extinguishing system. The water extinguishing system (extinguishing a fire with a continuous stream of water) is simple, reliable, and all ships without exception are equipped with it, regardless of their operating conditions and purpose. The main elements of the system are fire pumps, a main pipeline with branches, fire hydrants (horns) and hoses (sleeves) with barrels (fire nozzles). In addition to its direct purpose, the water extinguishing system can provide sea water to water irrigation, water spray, water curtain, foam extinguishing, sprinkler, ballast, etc. systems; ejectors of drainage and drainage systems; cooling pipelines for mechanisms, instruments and devices; pipelines for flushing sewage tanks. In addition, the water extinguishing system supplies water for washing anchor chains and hawses, washing decks and blowing out sea chests.

Rescue and fire-fighting vessels have special system water fire extinguishing system, independent of the general ship system.

The water extinguishing system cannot be used to extinguish burning oil products, since the density of fuel or oil is less than water, and they spread over its surface, which leads to an increase in the area engulfed in fire. Water should not be used to extinguish fires of varnishes and paints, as well as electrical equipment (water is a conductor and causes a short circuit).

The main pipeline of the system is made linear and circular. The number and location of fire horns must be such that two jets of water from independent fire horns can be supplied to any point of the fire. A fire horn is a shut-off valve that has a flange on one side with which it is connected to the pipeline, and on the other side a quick-release nut for connecting a fire hose. The sleeve with the barrel rolled into a ring is stored in a steel basket near the fire horn. On fire boats, rescue ships and tugboats, in addition to horns, monitors are installed, from which a powerful stream of water can be directed at a burning ship.

The pressure in the main must ensure a water jet height of at least 12 m. Centrifugal and (less often) piston pumps are usually used as mechanisms of the water extinguishing system. The supply and pressure of fire pumps are calculated based on the most unfavorable case of system operation, for example, from the condition of simultaneous operation of fire horns in the amount of 15% of the total number installed on the ship, water irrigation of ladders and exits from the MO, a water spray system in the MO, and a foam extinguishing system. According to the Register Rules, the minimum pressure at the shaft should be 0.28-0.32 MPa; and the water flow through the trunk is at least 10 m 3 / h.

The receiving pipelines of fire pumps are usually connected to kingstons, and the pump must be able to receive water from at least two places.

In Fig. 36 given typical diagram water fire extinguishing systems with a ring main.

To two centrifugal pumps 9 sea ​​water comes from Kingston 15 and from another highway 17 through the filter 13 and clinker valves 12. Each pump has a bypass pipeline with a non-return shut-off valve 11, allowing you to pump water in a closed loop (work “for yourself”) when there is no water flow to consumers. The pressure pipelines of both pumps are included in the ring main, from which depart: pipes to fire valves 2; pipeline 1 for washing anchor chains and hawses; branches - 3 to the MO spray system, 4 to the foam extinguishing system, 5 for washing wastewater collection tanks, 6 to the irrigation system for exits and watches.

Water spray and irrigation system. Sprayed water is one of the means of fighting fire. A fine spray of water creates a large evaporation surface above the fire, which increases the cooling efficiency and increases the rate of the evaporation process. In this case, almost all the water evaporates and an oxygen-depleted vapor-air layer is formed, separating the fire from the surrounding air. Several types of water-spray systems are used on marine vessels: sprinkler, water atomization, irrigation and water curtains.

Sprinkler system is designed to extinguish fire with sprayed jets of water in cabins, wardrooms, salons and office premises on passenger ships. The system got its name from the use of sprinklers - spray nozzles with a fusible lock. When the room reaches the appropriate temperature, the sprinklers automatically open and spray water within a radius of 2-3 m. The system pipelines are always filled with water under low pressure.

The sprinkler head (Fig. 37) consists of a housing 3, into which the ring is screwed 4, equipped with temples 6. In the center of diaphragm 5 there is a hole, around the perimeter of which solder is soldered, forming a seat / glass cap 8, serving as a valve. The valve is supported by a lock at the bottom 9, parts of which are connected by low-melting solder, designed for a melting temperature from 343 to 453 K (from 70 to 180 C) (depending on temperature regime premises), and for residential and office premises - about 333 K (60 °C). As the temperature rises, the solder melts, the lock disintegrates and the valve 8 opens under the pressure of water supplied to the hole 2. Water falling on a socket 7, splashes.

Sprinklers are also used, made in the form of a glass flask filled with an easily evaporating liquid, which boils when the temperature rises and bursts the flask under the pressure of the resulting vapors. The system includes a pipeline carrying sprinklers; control and alarm valve that allows water access to sprinklers and alarm devices; pneumatic-hydraulic tank with an automatically activated pump. The design of the tank and its automation are the same as in the domestic water supply system.

The water spray system (Fig. 38) is used to extinguish fires in military buildings, pump rooms, hangars, and garages.

It is carried out in the form of pipelines (lower 10 and upper 5) water spray, used to extinguish fire in the lower part of the compartment or at the top during flooding or an accident in the Moscow Region 17. Water sprayers are installed on the pipelines - jet 6 and slotted //. Water into a system protected by a safety valve 14, supplied from the fire main / through the overflow pipeline 13. To extinguish a spill under the flooring 7 fuel valves open 12, 15 and water from crevice sprayers 11 fan-shaped jets cover the surface of the second bottom flooring 8 and double bottom tank 9. When extinguishing burning fuel that has spilled on the surface of a flooded MO, open through the deck bushing 3 on the upper deck 2 using a roller drive 16 valve 4, water enters the upper water spray nozzles 6, from which it is directed downward in cone-shaped jets.

One of the types of water sprayers is shown in Fig. 39. The presence of a pin in the design of the water sprayer ensures sawing of water to the state of water dust emerging from the nozzle in the form of an almost horizontal fan. The diameter of the outlet of the water sprayer is 3-7 mm. The water pressure with the specified type of water sprayer is 0.4 MPa. 0.2-0.3 l/s of water is supplied per 1 m 2 of irrigated surface area. The irrigation system for ladders and exits is provided to protect people when exiting the Moscow Region in the event of a fire by irrigation of the entire exit route. The system is powered from the fire main, as well as from pneumatic sea water tanks. Irrigation systems are also used to lower the temperature in cellars where explosives and flammable substances are stored. In this case, the systems are run autonomously. A water curtain system exists on firefighting boats to cover the surfaces of the hull and superstructures of the vessel with continuous water curtains. The system creates flat water curtains using slotted water sprays, allowing the boat to approach a burning vessel and extinguish the fire on it from monitors. The system consists of pipelines with slotted water sprayers located on the sides of the boat. Required consumption water is provided by fire pumps. To create water curtains, 0.2-0.3 l/s of water is supplied per 1 m2 of protected area.

Steam extinguishing system. This system belongs to volumetric extinguishing systems, since the working substance fills the entire free volume of the enclosed space with saturated water vapor, inert for the combustion process, with a pressure not exceeding 0.8 MPa. The steam extinguishing system is dangerous for people, therefore it is not used in residential and office premises. It is used to equip fuel tanks, paint and lamp tanks, storerooms for storing flammable goods, main engine mufflers, oil pump rooms, etc.

Steam extinguishing pipelines running in premises must have their own isolation valves, concentrated at the central steam extinguishing station, equipped with distinctive

bold inscriptions and painted red. The steam extinguishing station should be located in heated rooms, reliably protected from possible mechanical damage. The steam extinguishing system must ensure that half the volume of the premises it serves is filled with steam in no more than 15 minutes. This requires pipes and extensions of appropriate sizes. Control of the steam extinguishing system must be centralized; the steam distribution box (manifold) must be installed in a place accessible for maintenance.

In a centrally controlled steam extinguishing system (Fig. 40), the steam distribution box 2 equipped with a pressure gauge and valves: shut-off 1, safety 3 and reduction 4. From distribution box steam is directed through shut-off valves into the main line with branches 6, going into the holds. Their number depends on the volume of the protected premises. The ends of the shoots are located at a height of 0.3-0.5 m from the flooring. By process 5 Steam from an off-ship source is supplied to the system through the pipe for connecting the hose.

The advantage of the steam extinguishing system is the simplicity of its design and operation, as well as the relatively low cost of manufacturing. The disadvantages of the system are that it can only be used in enclosed spaces; steam damages loads and mechanisms and is dangerous for people.

Carbon dioxide extinguishing system. Carbon dioxide can be used to extinguish fires in enclosed spaces (cargo holds, fuel tanks, MO and pump rooms, power plant premises, special storerooms). The essence of the action of carbon dioxide extinguishing is reduced to diluting the air with carbon dioxide to reduce the oxygen content in it to a percentage at which combustion stops. Thus, when carbon dioxide is introduced into a room in an amount of 28.5% of its volume, the atmosphere of this room will contain 56.5% nitrogen and 15% oxygen. At 8% oxygen content in the air, even smoldering stops.

Currently, gaseous and fog-like snow carbon dioxide is used to extinguish fires. Carbon dioxide comes out of the cylinder without a siphon (when the cylinder is positioned with the valve up) in a gaseous state. When released through a siphon tube (or when the cylinder is positioned with the valve down), carbon dioxide leaves the cylinder in liquid form and, cooling at the hole outside, turns into a fog-like state or takes the form of flakes.

Carbon dioxide at a temperature of 273 K (0 °C) and a pressure of 3.5 MPa has the ability to liquefy with a volume reduction of 400-450 times compared to the gaseous state. Carbon dioxide is stored in 40 liter steel cylinders with a pressure of up to 5 MPa.

According to the Register Rules, in the event of a fire, it is necessary to fill 30% of the volume of the largest dry cargo hold and 40% of the MO. According to the Register Rules, 85% of the estimated amount of carbon dioxide must be introduced within no more than 2 minutes - into machine rooms, rooms of emergency diesel generators and fire pumps, and other rooms where liquid fuel or other flammable liquids are used; 10 minutes - in rooms with vehicles and fuel (except diesel) in tanks, as well as in rooms where there is no liquid fuel or other flammable liquids.

There are high and low pressure carbon dioxide extinguishing systems. In a high-pressure system, the number of cylinders for storing liquefied carbon dioxide is determined depending on the degree of filling (the amount of carbon dioxide per 1 liter of capacity), which should be no more than 0.675 kg/l with a design cylinder pressure of 12.5 MPa or no more than 0.75 kg/l at a design cylinder pressure of 15 MPa or more. In a low-pressure system, the calculated amount of liquefied carbon dioxide should be stored in one tank at an operating pressure of about 2 MPa and a temperature of about 255 K (-18 °C). The degree of filling of the tank should be no more than 0.9 kg/l. The tank must be served by two autonomous automated refrigeration units, consisting of a compressor, a condenser and a cooling battery. Cylinder valves must be designed to prevent spontaneous opening under ship operating conditions.

Filling of cylinders and release of carbon dioxide from them is carried out through the outlet head - valve (Fig. 41), located in the upper part of the cylinder. The valve is connected to a siphon tube, which does not reach the bottom of the cylinder by 5-10 mm. The internal diameter of the tube is 12-15 mm, and the diameter of the passage channel in the outlet valve of the cylinder is 10 mm, which ensures a reduction in the area of ​​the passage channel by 20-30 mm 2 compared to the area cross section siphon tube. This is done to prevent carbon dioxide from freezing when it is released from the cylinder. Safety diaphragm made of calibrated brass

Rice. 41. Carbon dioxide cylinder outlet head with drive

from a cable or roller: A- the valve is closed; b- valve is open

1-safety membrane; 2-press lever; 3-start lever;

4- plate; 5-rod; 13 - cable or roller

or tin bronze withstands a pressure of 18±1 MPa and is destroyed at a pressure of more than 19 MPa. Safety pipelines and membranes connected to the cylinders allow carbon dioxide to be released into the atmosphere when the pressure in the cylinders increases beyond the permissible limit. This prevents its accidental release into the system pipelines. Carbon dioxide is released into the system through a membrane, which is cut by moving the knife-pipe downward.

A typical carbon dioxide plant with one station is shown in Fig. 42.

It consists of a group of cylinders 1, where liquid carbon dioxide is stored, collectors 2, 5 for collecting carbon dioxide coming from cylinders and pipelines 15 for its delivery to the premises. The outflow of carbon dioxide occurs through nozzles (nozzles) 16 from a ring pipeline 17, laid under the ceiling of the room. When expiring, carbon dioxide evaporates and turns into inert carbon dioxide CO 2, which is heavier than air and therefore settles down, displacing oxygen from the atmosphere. Valves are installed on the system pipelines (main stop 13, launchers 14), ensuring tight shut-off of the pipeline and quick start-up of the system. The pressure in the system is controlled by a pressure gauge 12. Each cylinder is equipped with a special outlet head 11 (see Fig. 5.48). All outlet heads are activated by a remote pneumatic drive 9, when compressed air enters through a pipe 10 piston 8 moves rods 6 And 4. The exhaust air escapes into the atmosphere through pipe 7. A detector 3 is installed to indicate the start of system operation.

In the station room, the air temperature should not exceed 313 K (40 °C), which is explained by the high pressure (about 13 MPa) of carbon dioxide at this temperature. The stations are located in superstructures and deckhouses with direct access to the open deck, equipped with ventilation and thermal insulation.

To extinguish fires, manual carbon dioxide fire extinguishers OU-2 and OU-5 with a capacity of 2 and 5 liters are also used.

The disadvantages of a carbon dioxide fire extinguishing system are a large number of cylinders, high price station equipment, significant costs for recharging cylinders and danger to personnel if safety precautions are not observed.

Foam extinguishing system. Designed to extinguish a fire by applying foam to a burning surface or filling the protected area with foam. The system is used to extinguish fires in cargo tank compartments, cargo compartments, cargo pump rooms, storerooms for flammable materials and substances, paint rooms, closed cargo decks of ferries and trailer vessels for transporting vehicles and mobile equipment with fuel in tanks, etc.

The foam extinguishing system must not be used to extinguish fires in the cargo spaces of container ships, or in spaces containing chemicals that produce oxygen or other oxidizing agents that promote combustion, such as cellulose nitrate; gaseous products or liquefied gases with a boiling point below ambient temperature (butane, propane); chemicals or metals,

reacting with water. It is not allowed to use the foam extinguishing system to extinguish fires of energized electrical equipment.

Air-mechanical foam of low (10:1), medium (50:1 and 150:1) and high (1000:1) expansion is used as a fire extinguishing agent in the foam extinguishing system. Under foaming ratio refers to the ratio of the volume of the resulting foam to the volume of the original foaming agent.

Chemical foam is formed by the reaction of solutions of acids and alkalis in the presence of special substances that give it stickiness. Air-mechanical foam is obtained by dissolving the foaming composition in water and mixing the solution with atmospheric air. Foam is several times lighter than water and oil products and therefore floats on their surface. Unlike other fire extinguishing agents, it can effectively extinguish burning oil products on the surface of the sea.

The foam is not dangerous to people, is not electrically conductive, does not spoil cargo and petroleum products, and does not cause corrosion of metals. Foam released onto the fire isolates it from atmospheric oxygen, and combustion stops.

Chemical foam is produced from foam powders in foam generators. Foam powders are stored on board the ship in hermetically sealed metal cans. The main disadvantage of chemical foam extinguishing is the unpreparedness of foam generators for immediate action, since if a fire occurs, it is necessary to open cans of powder, which is very labor-intensive and time-consuming. Therefore, chemical foam extinguishing is rarely used on modern ships. More often they use air-mechanical foam, consisting by volume of 90 % air, 9.8% water and 0.2% foaming agent (special composition liquid).

Recently, two types of air-mechanical foam extinguishing systems have become widespread on sea vessels, differing in the method of mixing the foaming agent with water and the design type of devices in which the foam is produced.

In Fig. Figure 43 shows a schematic diagram of an automatic dosing unit with a foam agent supplied by a pump. Dosing devices are designed to produce a solution of a foaming mixture of a given concentration with automatic adjustment.

The foaming agent enters the tank 3 through deck bushing 2 from deck/. The foaming agent is drained from the tank through valve 5, a bulkhead glass and a flexible hose 4. The foam agent enters the pump 6, pressure protected safety valve 8, valve 10 opens the flow of foam concentrate into the dispenser 12, where it mixes with water coming from the fire water system through the valve 14. The water pressure in front of the dispenser is measured with a pressure gauge 13. From the dispenser, the solution of the foaming mixture enters the line of the foam extinguishing system //. Manual adjustment valve 9 allows excess amount of foaming agent to be directed into the tank 3 with valve 7 open. The concentration of the foaming mixture solution is automatically adjusted by the valve 16 with drive 15.

The device of the air-foam barrel is shown in Fig. 44. When passing through a tapered nozzle, the jet of dissolved foaming agent acquires a high speed with which it enters the perforated diffuser. Through the holes of the diffuser it is sucked ambient air, resulting in the formation of air foam.

In Fig. Figure 45 shows a diagram of a high expansion foam fire extinguishing system with a fresh water tank and a dosing device. The system consists of a reservoir with a supply of foaming agent, stationary foam generators, and isolation valves. Under the pressure of water coming from the pump, the foaming agent is forced through the pipeline into the line to the foam generators. Throttle washers create different high-speed pressures of water and foaming agent flows, thereby ensuring their mixing in a certain proportion and producing an emulsion. In foam generators, when the emulsion is mixed with air, foam is formed.

The GSP type foam generators used in the system have a high foaming rate (over 70), large flow rate (over 1000 l/s), and a foam jet ejection range of 8 m at

Rice. 44. Air-foam barrel

1 - connecting nut; 2 - rubber ring; 3 - nozzle;

4 - screw; 5 - casing; 6 - diffuser; 7 - foam line

Rice. 45. Schematic diagram of a fire extinguishing system with high expansion foam

/ - fresh water tank; 2, 5, 6, 8, 9, 12, 16, 19 - straight-through shut-off valves; 3 - centrifugal pump; 4, 10 - nanometers; 7 - reservoir with foaming agent; // - foam: generator; 13 - foam concentrate supply pipeline; 14, 18 - throttle washers; 15 - line to foam generators; 17 - drain pipeline; 20 - fire main

pressure in front of the generator is 0.6 MPa. SHG generators can be stationary or portable.

The portable generator is shown in Fig. 46.

It consists of a spray head 1 with quick-locking nut type PC or ROT, confuser 2, housing 3 and outlet diffuser 4 with flange 5. A hose is connected to the head nut, through which the emulsion is supplied to the generator. The diffuser has a mesh installed 6, providing the release of a compact stream of foam.

The reliability and speed of operation of the multiple foam extinguishing system ensures its high efficiency in extinguishing oil products. Due to these qualities, foam extinguishing systems are widely used on bulk carriers and especially on tankers.

Rice. 46. ​​Portable foam generator Fig. 47. Schematic diagram of the system OXT

Volumetric chemical extinguishing system. These systems have become widespread for extinguishing fires in the Ministry of Defense and cargo holds of dry cargo ships using a volumetric method, i.e., using vapors of easily evaporating liquids. The advantage of a volumetric chemical extinguishing system (VCT) compared to a carbon dioxide extinguishing system is that the easily evaporating extinguishing liquid is stored at low pressure, as a result of which the possibility of its loss from leakage is significantly reduced. Composition BF-2 is used as a fire extinguishing liquid - a mixture of ethyl bromide (73%) and freon F-114-V (27 %) - or pure F-114V 2. The use of BF-2 in ship conditions is preferable, since vibrations and elevated temperatures cause leakage of fire extinguishing liquid through pipeline connections.

OXT liquid exceeds carbon dioxide in fire extinguishing properties: for every 1 m 3 of room volume, 0.67 kg/min of carbon dioxide is required to extinguish a fire with petroleum products, and the BF-2 composition requires only 0.215 kg/min. OXT liquid is stored in tanks and supplied to the fire site using compressed air with a pressure of 0.5-1 MPa. The cylinders are placed at the liquid extinguishing station. A pipeline is drawn from the cylinders to each protected room, which ends in the upper part of the premises with spray heads. If the room height is more than 5 m, two tiers of sprayers are installed.

In Fig. Figure 47 shows a schematic diagram of the OXT system.

The fire extinguishing liquid is in the cylinder 1, and the compressed air necessary for the operation of the system is in the cylinder 2. The system is equipped with a pressure gauge 9 and valves: shut-off 4, 8, safety 10, reducing 5, in which the air pressure is reduced to the required one. Compressed air entering the cylinder displaces the extinguishing liquid through a siphon tube 11 into the distribution line 6. Using sprayers, the liquid is sawn throughout the room. At the end of work, the system pipelines must be purged compressed air pipeline 3 and valve 7 to remove residual liquid. The room must be well ventilated.

Inert gas system. Fire protection systems of tankers are being improved taking into account advanced domestic and foreign experience. In recent years, the International Maritime Organization (IMO) and the Maritime Register have paid special attention to the group of fire protection systems that prevent fires or explosions on tankers. These primarily include an inert gas system for cargo and slop tanks and devices to prevent flame penetration into tanks.

The inert gas system is designed to actively protect tanker cargo compartments from fire and explosion by creating and constantly maintaining an inert (non-flammable) micro-atmosphere with an oxygen content of no more than 8 by volume. %. In such an oxygen-depleted environment, it is impossible for the hydrocarbon vapors emitted by the transported material to ignite.

Rice. 5.55. Schematic diagram of an improved tanker inert gas system 1 - chimney of auxiliary boilers; 2 - valve cleaning device; 3 - direct-contact gas cooling and purification devices; 4 - droplet separator; 5 - gas supply to tanks; 6 - reception of inert gases from the shore; 7 - deck water seal; 8 - Kingston box; 9 - sublimator; 10 - gas blowers; AND- drain overboard; 12 - water supply pumps to the deck seal; 13 - receiving water from Kingston MO; 14 - sea water cooling pump; /5 - pipeline from the backup pump of auxiliary mechanisms; T- temperature relay; APT- emergency temperature relay; RD - pressure switch; ORD- operational pressure switch; RVD, RID- upper and lower pressure relay; O, - remote oxygen control; AVU, ANU- emergency sensors of the upper and lower level", SVU- high level alarm; ----- inert gases; - - - cargo;---- sea water;--------- water drainage; X household item

Cargo or its residues on the internal surfaces of cargo tanks.

Let's consider the inert gas system of a modern Pobeda type tanker, where exhaust flue gases from one of the two auxiliary boilers are used as protective inert gases. At thermal loads of at least 40%, the boilers are generators of inert gases with a low (up to 5% by volume) oxygen content and a temperature in the gas extraction area not exceeding 533 K (260 °C); upon reaching the rated thermal load, the gas temperature rises to 638 K (365 °C).

The maximum amount of exhaust gases taken from the boiler chimney is 1.25 times higher than the total supply of the cargo pumps installed on the tanker, which corresponds to 7500 m 3 /h or 30% of the total amount flue gases emitted into the atmosphere through the chimney. With these parameters, inert gases enter the technical air conditioning system and are supplied to cargo and settling tanks.

The system works as follows (Fig. 48). Due to the vacuum in the suction section created by the operating gas blower, inert gases sequentially pass through contact-direct-flow coolers-gas purifiers of the first and second stages, the design of which is shown in Fig. 49. Inert gases are cooled due to intensive contact with sea water supplied to the apparatus from below through a swirler with blades. At a sea water temperature of 30 °C, the temperature of the inert gases at the outlet of the second stage apparatus is 35 °C.

The system provides for two-stage gas purification from soot, mechanical impurities and sulfur compounds. The presence of two stages of purification increases the time of active contact of the two-phase medium (gases - water) and thereby helps to increase the efficiency of this operation. As a result, from 99.1 to 99.6% of sulfur compounds are removed from the exhaust gases.

Cooled and purified inert gases at the exit from the active zone of the devices undergo primary separation of the water they contain.

This operation is carried out in a spray separator with profiled blades, where, as the gas flow moves, centrifugal forces separate the gas-water mixture into phases; in this case, water is removed from the apparatus overboard, and inert gases enter the droplet separator (Fig. 50). It produces secondary separation, based on the principles of changing the direction of the flow of wet gases and centrifugal separation of media in a swirler with profiled blades. The separated moisture is removed overboard through a common drain pipeline, and inert gases are pumped by a gas blower into the deck distribution line through the deck water seal. The latter prevents hydrocarbon vapors from entering the ship's premises through transit pipelines of inert gases when the gas blower is not operating.

The principle of operation of the water seal (Fig. 51) is based on the hydraulic closure of the inert gas pipeline when the gas blower is not working, and when it is operating, on pressing the water level behind the reflector to allow the passage of inert gases. This prevents the flow of flammable hydrocarbon vapors into the ship's premises and the carryover of water from the seal into the cargo compartments during steady-state operation of the system. For this purpose, the valve is equipped with a special rotary device, consisting of a valve with a counterweight, to which is attached the open end of a flexible hose, which serves to remove water from the water cavity of the valve and ensure continuous circulation of water in it when the inert gas system is working and not working. Water circulation in the gate is carried out by two centrifugal pumps, one of which is a backup pump. Water from the gate is drained overboard through a seacock located in the cargo pump room. The valve is equipped with sight glasses, a water indicator column, a steam line for heating the water cavity and means automatic control water level and temperature.

From the deck water seal, through a non-return shut-off valve installed behind it, inert gases enter the deck distribution line and are supplied to the cargo compartments, on the branches of which non-return shut-off valves are also installed.

The inert gas system operates in the following cases:

during the initial filling of cargo compartments with inert gases before accepting cargo;

during the passage of a tanker with cargo or ballast, when loading the tanker to maintain a given excess pressure of inert gases from 2 to 8 kPa and periodically pumping them into the tanks when the pressure drops below the specified value;

when unloading petroleum products to replace them with inert gases;

when washing tanks with stationary means, including crude oil;

when ventilating cargo compartments with inert gases and degassing

zonation of tanks with outside air.

Gas and air exchange in cargo tanks is determined by the operating modes of the inert gas system (Fig. 52). To effectively carry out this process, each cargo tank has a deck inlet for inert gases, a purge pipe and an autonomous gas exhaust system. Columns of purge pipes and gas outlets (Fig. 53) are equipped with automatic gas outlet devices that provide a gas-air flow velocity of at least 30 m/s in all operating modes, which eliminates the penetration of flame into tanks and gas contamination of the ship’s deck and helps improve working conditions for crew members.

The inert gas supply pipeline and the purge pipe are spaced both along the length of the tank and from the blast furnace, which ensures effective gas exchange, which helps accelerate the creation of a uniform low concentration of oxygen or an environment close to atmospheric oxygen concentration after degassing. For purging (if necessary) of the cargo system with inert gases, a jumper is provided between it and the inert gas system, equipped for safety reasons with shut-off devices and an air cap.

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