3.7 Breathing apparatus with an open breathing pattern

Air balloon unit AVM-1m  (Fig. 3.26) - an autonomous apparatus operating on compressed air. Included in a set of equipment for swimming. Consists of air cylinders, rigidly fastened together, shut-off valve, breathing machine, mouthpiece box with a mouthpiece, corrugated tubes of inhalation and exhalation, remote minimum pressure indicator with pressure gauge and mounting shoulder-belt belts, foam insert that allows you to adjust the weight of the device in the water ( lead to zero buoyancy).

Fig. 3.26. Air-balloon unit AVM-1m: 1 - valve box; 2 - headband; 3 - breathing machine; 4 - stop valve; 5 - foam insert; 6 - fastening belts; 7 - cylinders; 8 - remote minimum pressure indicator with pressure gauge

Air balloon unit AVM-3  (Fig. 3.27) is part of the equipment of the VCA. Unlike the AVM-1m, it has a panel on which all parts of the device are mounted. The AVM-3 breathing machine allows you to supply air for breathing from your cylinders and through the hose from the surface of a hand pump, a ship’s main line, or from a transport cylinder.

  Fig. 3.27. Air-balloon apparatus AVM-3: 1 - inspiration tube; 2 - valve box with atmospheric valve; 3- expiratory tube; 4- breathing machine; 5 - shoulder strap; 6 - cylinders; 7 - foam insert; 8-belt; 9 - pressure reducing valve; 10 - stop valve; 11 - charging nipple; 12 - gearbox; 13 - manometer; 14 - backup supply valve; 15 - diving hose

  Fig. 3.28. Air-balloon apparatus AVM-5: 1 - gearbox with shut-off valve and reserve air valve; 2 - breathing machine; 3 - cylinder

The AVM-5 and AVM-6 devices differ in the capacity of cylinders and belong to the autonomous-hose group, and the AVM-7 and AVM-8 - to the group of autonomous vehicles. With stand-alone use, all devices can be used in one-balloon and double-balloon versions. The ABM-5 and AVM-6 devices, when used in the hose version, can be used only with two cylinders, with one of the cylinders of the device acting as a low-pressure tank to reduce inspiratory resistance, and the second serves to save reserve air in case of a sudden cessation of air supply on the hose from the surface. The devices are equipped with a cargo belt, a VM-4 mask and fittings for switching to a single balloon version. Delivered in a stacking box.

Air balloon apparatus "Ukraine" - double balloon, back with two shut-off valves. It differs from the AVM-1m by the presence of two shut-off valves of cylinders, the design of a breathing machine and the sealing of the fittings. There is no gear in this device. The air from the cylinders goes directly to the valve of the machine. Instead of a remote gauge, a beeper is used in it. The device is part of the equipment for swimming and is used in the rescue service OSVOD and in sports clubs.

Air balloon apparatus "Ukraine-2"  similar to the device AVM-7. Mainly used for sporting purposes.

Hose devices SHAP-40 and SHAP-62  (Fig. 3.29, 3.30) are a kind of air-balloon apparatus. Breathing in them is provided by the air supplied through the hose from the surface, and the air in the cylinders of the apparatus serves as a reserve reserve and is used in case of interruption of the air supply through the hose. Hose devices are used mainly for rescue work and work on limited areas, but requiring a long time to perform.

Respiratory (pulmonary) automata of devices with an open breathing pattern are designed to automatically supply air during inhalation (air balloon and hose apparatus) with a certain amount of vacuum in the cavity of the automaton. They can be with a direct-acting valve (with air pressure under the valve tends to open the valve) and a return valve (with air pressure on the valve). Respiratory machines are divided into one-and two-stage.

Respiratory automatic machine apparatus AVM-1m  (Fig. 3.31) - reverse action, combined with a gearbox. The valve opens with levers on which the membrane presses when a vacuum is formed. The air in the cavity of the machine is supplied by a pulsating flow to inhale. When exhaling, the valve is closed. The exhalation valve is located in the body of the machine above the membrane.

  Fig. 3.29. Hose unit ШАП-40: 1 - inspiration tube; 2 - mouthpiece box; 3 - expiratory tube; 4 - headband; 5 - breathing machine; 6 - shoulder strap; 7 - cylinder; 8 - waist belt; 9 - stop valve; 10 - charging socket; 11 - frame; 12 - diving hose

  Fig. 3.30. Hose apparatus ШАП-62: 1 - inspiration tube; 2 - valve box with atmospheric valve; 3 - expiratory tube; 4 - protective casing; 5 - shoulder strap; 6 - a panel with a facing of porous rubber; 7 - breathing machine; 8 - fitting for connecting the diving hose; 9 - charging nipple; 10 - waist belt with quick release lock; 11 - stop valve; 12 - connecting fittings; 13 - gearbox; 14 - cylinder

Fig. 3.31. The breathing machine of the AVM-1m apparatus with a gearbox: 1 - cover; 2 - upper arm; 3- membrane; 4 - exhalation valve; 5 - lower arm; 6 - machine body - 7 - valve seat; 8 - automatic valve; 9 - inlet fitting; 10 - strainer; 11 - gearbox valve; 12 - safety valve

  Fig. 3.32. The respiratory automaton of the AVM-3 apparatus: 1 - cover; 2 - membrane; 3 - adjusting screw; 4 - valve seat; 5 - inlet fitting; 6 - filter; 7 - automatic valve; 8 - fitting diving hose; 9 - lower arm; 10 - the upper arm, 11 - the body of the machine

  Fig. 3.33. The respiratory automaton of the “Ukraine” apparatus: 1 - expiratory valve; 2 - upper arm; 3 - automat cover; 4 - lower arm; 5 - membrane; 6 - membrane cover; 7 - clamp; 8 - the body of the machine; 9 - valve seat; 10 - valve; 11 - inlet fitting; 12- cuff; 13 - minimum pressure indicator rod; 14 - pointer whistle; 15 - pointer cocking handle; 16 - pivot axis

The respiratory automaton of the apparatus SHAP-40 differs from the automaton of the AVM-1m apparatus by the presence of a nozzle for connecting a diving hose and an audible minimum pressure indicator.

  Fig. 3.34. The breathing machine of the AVM-5, AVM-6 and Ukraine-2 devices: 1 - cover; 2 - valve lever; 3 - hand drive lever; 4 - valve; 5 - inlet fitting with valve seat; 6 - filter; 7, 9 - exhalation valves; 8 - bump guard; 10 - body

In direct-acting gearboxes, high gas pressure tends to open the valve, in reverse-action gearboxes, on the contrary, gas pressure tends to close the valve of the pressure regulator. Lever gearboxes of direct action are used in devices AVM-1m, AVM-1m-2, AVM-3, SHAP-40, SHAP-62.

Pointers minimum pressure gauges  - devices that signal a decrease in the gas pressure in the apparatus cylinders to a predetermined value. The principle of the pointers is based on the interaction of two forces of gas pressure in cylinders and the opposing force of the spring. The pointer is triggered when the force of the gas pressure becomes less than the force of the spring. In breathing apparatus used pointers of three designs: stock (it is also a portable), dyuzuyu and sound.

  Fig. 3.35 Lever reducer direct action apparatus AVM-3: 1 - inlet fitting; 2 - gearbox housing; 3 - regulating sleeve; 4 - membrane; 5 - safety valve; 6 - outlet fitting; 7 - lever; 8 - pusher; 9 - adjusting screw; 10 - valve gear

  Fig. 3.36. The rod remote indicator of the minimum pressure of the apparatus AVM-1m: 1 - pressure gauge; 2 - membrane; 3 - tee; 4 - high-pressure hose; 5 - stock; 6 - adjusting nut; 7 - pointer with a button; 8 - pointer housing

Dyuzovy A (physiological) indicator (Fig. 3.37) or a backup air supply valve in various designs has been used in AVM-1m-2, AVM-3, AVM-5, AVM-6 and Ukraine-2 devices. It is a locking device with a movable locking part and a bypass hole (nozzle). The locking part has a spring to keep the valve pressed to the seat. With a pressure in cylinders greater than the minimum, the spring is compressed and the valve is raised above the saddle. The air at the same time freely passes through the line. When the pressure drops to the minimum valve under the action of the spring falls on the saddle and closes the main passage. Only a workaround remains - through a nozzle with a throughput of 5-10 l / min. This amount of air to breathe is not enough. A sharp lack of air for breathing also serves as a physiological signal about the exhaustion of air to a minimum (reserve) reserve. Normal flow is restored by turning the valve stem with a flywheel or by using traction. In this case, the valve rises with the axial stroke of the rod and opens the main air passage.

Sound  the pointer (signaling device) is applied in the “Ukraine” and SHAP-40 devices. It is mounted in the casing of the gearbox and breathing machine (see. Fig. 3.33). The design principle of the actuating device is similar to the stock pointer. When air drops in the cylinders, the rod is actuated and the air supply to the whistle opens, which makes a characteristic sharp sound.

Valve and mouth boxes (Fig. 3.38) are used to connect the breathing apparatus to the human respiratory organs. Unlike a mouth-valve box, it has a cork valve and inhalation and exhalation valves to distribute the flow of inhaled and exhaled gas. The boxes are made of non-ferrous metal of various designs: with a combined and separate cork valve body. Threaded connections valve boxes of all designs are the same. On the case of valve boxes of many devices there is a hole with a fungus-shaped shield, intended for switching to breathing with atmospheric air.

The holding's enterprises produce products for various industries, including shipbuilding and marine engineering.

SHAP-R

Air breathing apparatus SHAP-R is designed to provide breathing diver when working at depths of up to 60 m with pulmonary ventilation up to 60 l / min when working in the hose version, as well as in the stand-alone version and for emergency ascent. He is able to work in conditions of heavy pollution, which allows rescue work, for example, in case of oil spills. Today, he has already been adopted by the MES.

All the main components of the device are located in a compact impact-resistant plastic housing;
   - The special design, made in a streamlined form, allows you to work in cramped conditions;
   - Eliminates the possibility of hooks and entanglement, prevents from any mechanical damage;
   - The device has additional ports of medium pressure for connecting a second pulmonary automaton, a hose for blowing a hydro-overalls or a buoyancy compensator vest, as well as a pneumatic tool;
   - A special feature is also the design of the unit connecting the device to the diving hose, which allows you to manually (without using tools) disconnect the diving hose in any conditions, including: under water under pressure, as well as when leaving the water at low temperatures.
   - The device SHAP-R can be used (as a backup) in equipment with diving helmets such as Super Lite, X-Lite, etc .;
   - A gearbox with a dry etching chamber, as well as a lung machine used in the apparatus, allows operation at extremely low temperatures of water and air, as well as in highly polluted water.

AVM-15

The air-breathing apparatus AVM-15 is designed to provide the diver’s breathing when they perform underwater technical, rescue and other types of diving work in an autonomous and hose version, including in conditions of low water and air temperatures, as well as in polluted environments, including with a high content of petroleum products.

The device works on an open breathing system (inhale from the device, exhale into the water).

The AVM configuration includes 3 types of gearboxes (piston, diaphragm with a dry chamber, piston with a “dry etch chamber”) and 2 types of pulmonary automatons LAM-17 (with a mouthpiece) and LAM-17R (with a threaded fitting for working in UGK- 3).

The device provides breathing diver when performing diving operations at depths of up to 60 m with pulmonary ventilation up to 60 l / min;
   - The device can be converted to work in the hose version;
- In addition to compressed air, it can be used with oxygen-enriched breathing gas mixtures, which significantly increases the efficiency of diving operations;
   - The device, when a second pulmonary machine is connected to it, ensures the breathing of two divers simultaneously;
   - Meets the requirements of GOST R 52639 and EN 250;
   - Unlike previous devices (AVM-5, AVM-7) in the AVM-15, high and medium pressure ports are adapted to the European standard;
   - All nodes that are part of the device AVM-15 are completely interchangeable with imported counterparts;
   - The device includes a patented signaling device of a “bubble” type, which signals the exhaustion of the main air supply;
   - Used on off-shore boats of the complex rescue support of the project 23040.

AVM-21 "MORZH"

The air-breathing apparatus is designed to ensure the breathing of a diver when he performs underwater technical, rescue and other types of diving work in the autonomous and hose versions, in conditions of low water and air temperatures, as well as in polluted environments, including those with elevated levels petroleum products.

The new technology used in the device solves the problem of pulmonary frosting in extreme cold conditions, due to which the aqualung can work reliably at a temperature of up to -4 degrees for at least two hours. The gearbox, designed to reduce the air pressure and feed it to the pulmonary machine, thanks to a new technology, is simpler and more reliable than its analogues and previous developments. In addition, springless technology has reduced the overall weight of the equipment.

The device works according to an open breathing system (inhale from the device, exhale into the water);
   - The units of the apparatus are located in a shock-resistant plastic case;
   - Capacity of cylinders 2 * 7 l;
   - Working pressure 300 kgf / cm 2;
   - Operating time at 30 l / min is 120 minutes;
   - Thanks to the latest lam-21 automatic luminaire, the device is operational at a water temperature of up to -4 ° C.

it is intended for circulating recirculation cooling of various non-aggressive liquids in process or other industrial equipment.

Draykuler - air coolers EUROMASH series ABOwe have developed for cooling various liquid media (mainly water and ethylene glycol / propylene glycol solutions) in technological processes in the refining, petrochemical, chemical and other industries with a pressure of the cooled medium not exceeding 0.6 MPa (kgf / cm²) and its temperature not exceeding 100 o С in climatic conditions of type U1 and UHL1 according to GOST 15150.

Most often, these heat exchange systems are used in cases where an almost continuous cooling process is required.

The drawing on the right above shows the overall dimensions of the device. EUROMASH ABO-350-14 / 6. It is characterized by the presence of an axial fan No. 14 with a 6-pole electric motor with a power of 15 kW at 1000 revolutions per minute and two V-shaped heat exchangers on a steel pipe with aluminum fins with a heat exchange surface area of ​​172.4 m² each.

And in the drawing on the right shows the overall dimensions of the device EUROMASH ABO-175-12,5 / 8. It is characterized by the presence of an axial fan No. 12.5 with an 8-pole electric motor with a power of 4 kW at 750 revolutions per minute and one heat exchanger on a steel pipe with aluminum fins with a heat exchange surface area of ​​172.4 m². His photos are presented in this section of our Catalog.

Interpretation of the designation of air coolers ABO EUROMASH

Operating conditions for ABO EVROMASH devices

The drawing on the right shows the overall dimensions of the device EUROMASH ABO-175-08 / 4.

It is characterized by the presence of an axial fan No. 8 with a 4-pole electric motor with a power of 3 kW at 1500 revolutions per minute and one heat exchanger on a steel pipe with aluminum fins with a heat exchange surface area of ​​172.4 square meters.

Technical characteristics of ABO EVROMASH devices

The device and the order of the apparatus ABO EUROMASH. Passport ABO.

  has a frame made of steel profile. Inside the frame is an axial fan and heat exchanger (or two heat exchangers). The heat exchanger is made of steel pipes with knurled aluminum fins. The heat exchanger is a non-separable unit.

The coolant is fed into the heat exchanger and is discharged from it through nozzles protruding from the housing. Axial fan provides the necessary air flow. The air is sucked through heat exchangers, heated in them and ejected by the fan.

In order to avoid freezing of heat exchangers in case of emergency termination of circulation of the cooled medium in winter time, it is necessary to carry out the blowing of heat exchangers. Therefore, when connecting to the system, it is necessary to provide drain connections with valves.

The air-cooling apparatus is controlled from a remote or remote control, or with the help of a frequency converter. Elements of automatic control of the flow rate of the cooled medium can be provided in the project, but they are not included in the standard package

For cooling water or solutions of ethylene glycol or propylene glycol, we produce devices:

•   - exhaust apparatuses with two heat exchangers arranged with delta-like or with one heat exchanger and upper horizontal arrangement of the fan (an example of such an apparatus is shown in the photo on the right). In some cases, they can serve as replacements for AVG and 2AVG;
•   - devices with one or two vertically arranged heat exchangers and a vertical arrangement of the fan (an example of such an apparatus is shown in the photo below).

These devices are simple and reliable. They are produced by our company for many years. The photo of one of the largest devices in the standard range of AO2 models is in the photo on the right.

The high efficiency of using the AO2 model air-cooling apparatuses is achieved due to the well-thought out design of the equipment of this series. High-quality execution of devices provides high reliability and durability.

When they are used, the cooling of the liquid is carried out fairly quickly, and the set level of the temperature of the cooled medium when using control automation is maintained with high accuracy.

The operation of these devices is quite simple and convenient, it is absolutely safe.

NOTE

ONCE AGAIN, WE PAY ATTENTION: the selection of any necessary air-cooling apparatus is made solely by filling out, or the online form below, which will be easier for you to fill out. In the absence of initial data (type of cooled liquid, its volume, the temperature from which the liquid will be cooled, the temperature to which it will be cooled, the region of application of the device) it is impossible to find a dryer.

AVM-5 scuba adjustments

1. Adjusting the setting pressure of the gearbox
   2. Adjust the actuation of the safety valve gear
   3. Adjustment of the lung machine
   4. Adjustment of the bypass valve (reserve)

Adjusting the setting pressure of the gearbox (8-10 MPa)

1. Measurement of the value of the installation pressure.
   Disconnect the lung machine.
   Connect a test pressure gauge to the hose (0-16 MPa).
   Close the valve on the test gauge.
   Open the main air inlet valve.
   Measure pressure (8-10 ati).
   Close the main air supply valve.
   Open the valve on the test gauge (bleed air)
   2. Adjustment.
Unscrew the gearbox cover (1) Fig.4
   Pull out the piston (2) Fig.4. To do this, screw in the puller (or pick up the screw) into the threaded hole in the upper part of the piston and pull the puller. Further, the piston can be easily pulled out. Using a screwdriver, and trying to pick up the piston by the edge is not recommended.
   To increase the installation pressure, it is necessary to compress the spring of the gearbox (3) Fig.4
   To reduce - the spring must be loosened.

Produced two types of gearboxes.
   In the first case, to adjust the set pressure, it is necessary under the spring (3), to attach or remove special adjusting washers.
   In the second case it is necessary to mix the adjusting nut (7) along the thread of the sleeve (8) Fig.4.
   In this and in another embodiment, the meaning of all actions is to compress or release the spring (3)
   Next, the gearbox is assembled and the set pressure is measured again.

Manipulations for adjustment and measurement are made until the set pressure is 8-10.

Adjustment of operation of the safety valve (10-12 MPa)

All operating instructions for scuba AVMs recommend adjusting the response of the safety valve to a repair-control installation (RCU).
   The safety valve is screwed on a special fitting on the CGS. Pressure is supplied to the valve, and the force of the spring compression (11), fig.5, the valve is adjusted to the desired pressure.

In practice, the adjustment is performed in a slightly different way.
   1. Adjust the gearbox to set pressure
   2. Unscrew the locknut on the safety valve
   3. Slowly rotating the valve body (12) Fig.5 counterclockwise, to achieve a position at which the valve starts to operate.
   4. Screw the valve body (12) clockwise half a turn, and the valve will stop venting the air.
   5. Tighten the locknut.

Thus, we will adjust the valve to the opening pressure, which will be slightly higher than the set pressure (0.5-2 MPa)

Pulmonary adjustment

The instruction manual for scuba says that the lung machine is not adjustable.
In practice, the adjustment of ease of breathing (resistance to inhalation) can be carried out by bending the lever (5) Fig.6. When the lever is pushed in, the distance between the diaphragm (4) and the lever (5) in Fig. 6 changes, the greater the distance, the greater the resistance to inhalation. It should be noted that if the pulmonary machine is adjusted correctly, then when it is placed in water, air will randomly go up with a mouthpiece upwards. If the lung machine is turned down with a mouthpiece down (as shown in Figure 6), the air stops flowing.

Adjusting the operation of the relief valve (reserve)

1. Measure the pressure of the overflow valve adjustment.
   When measuring this value, it is necessary to charge the device to a pressure of at least 80 MPa.
   Unscrew the gearbox and lung machine.
   With the reserve air supply valve closed, open the main air supply valve.
   Bleed the air.
   When the air stops coming out, screw the high-pressure test pressure gauge (0-250 atm) to the fitting (instead of the reducer).
   Close the valve on the pressure gauge.
   The gauge should indicate 0 ati.
   Next, open the reserve air supply valve, and wait until the pressure in the cylinders becomes equal (the characteristic noise of the flowing air will be heard).
   The pressure that the gauge will show will correspond to the pressure of the reserve air.
   Multiplying the obtained value by 2, we obtain the response pressure of the bypass valve.
   The reserve air reserve should be in the range of 20-30 MPa, respectively, the response pressure of the relief valve should be in the range of 40-60ATI.
   2. Adjustment
   If the measurement results show the need for adjustment.
   Bleed air from the cylinders.
   Loosen hose clamps
   Loosen adapter union nuts (gas wrench can be used).
   Spread the cylinders and remove the adapter (3)
   In the place of fastening of the adapter (3) to the cylinder with valves, access to the adjusting nut of the bypass valve will open.
   While squeezing or uncoupling the spring of the relief valve, use the adjusting nut to change the setting. If it is necessary to increase the adjustment pressure, compress the spring (turn the nut clockwise), if you decrease it, release the spring.
   3. Collect the balloon.
   4. Charge up to 80 ati.
   5. Make a measurement.
   6. Repeat the adjustment if necessary.

O-rings and machine lubrication

To ensure the tightness of the connections, the device uses rubber sealing rings of various diameters.
To prevent "drying", the rings must be lubricated. For lubrication used technical petrolatum (TsIATIM 221), or its substitutes.
   The lubricated ring must be placed in a lubricant, allowed to stand for some time (5-10 min.), Then cleaned of excess lubricant and set in place.
   In addition, the device lubricates the friction parts of the gearbox (piston). Grease is applied and then excess is removed.

The frequency of inspections apparatus.

Working test - before each descent
   Minor check (check all adjustments, lubricate o-rings) - before the start of the season
   Full check (small check + full disassembly and assembly) - upon receipt from the warehouse, if in doubt, after long storage

The breathing apparatus AVM-3 (fig. 36) consists of the following main parts:

• respiratory machine, which serves for pulsating supply of air at the time of inhalation and stopping the supply at the time of expiration;
• reducer designed to reduce the pressure of compressed air in the cylinders of the apparatus (150 kgf / cm 2) to the installation of 3-4 kgf / cm 2;

• two air tanks with a capacity of 5 liters each, for a working pressure of 150 kgf / cm 2, which contain a supply of compressed air;
• valve that serves to block the release of compressed air from the cylinders;
• backup supply valve used to supply reserve air from the apparatus cylinders;
• a valve box designed to connect the apparatus’s breathing system to a hydro-overalls helmet or a mabka;
• high-pressure manometer, which serves to control the pressure in ankhp arata cylinders;
• tubes of inhalation and exhalation, used to connect the valve box with a breathing machine.

  Fig. 36. Schematic diagram of the apparatus AVM-3:
    1 - breathing machine; 2 - gearbox; 3 - cylinders; 4 - valve; 5 - backup supply valve; 6 - valve box: 7-gauge; 8 - inspiratory tube; 9 - tube outflow; 10 - valve valve; 11 - nozzle; 12 - metal membrane; 1Z - spring; 14 - valve gear; 15 - breathing valve; 16 - the membrane; 17, 18 - levers; 19 - breathing machine saddle; 20 - exhalation valve; 21 - petal; 22 - safety valve; 23 - valve (check); 24 - spindle; 25 - hard center; 26 - inlet fitting; 27 - VS-1 hose; 28 - valve (check); 29, 30 - filters

  The principle of operation of the AVM-3 with autonomous breathing. The air from the cylinders of the apparatus is supplied as follows; Before the diver begins to dive, they open the valve 4 on the cylinders and close the valve 5 of the reserve supply. Through the open valve of valve 4 and the nozzle in valve 5, the air pressure propagates under the diaphragm into cavity B, bends the diaphragm, overcoming the force of the valve spring 13, and opens the seat through which air passes under the valve of the reducer.

  In the reducer, the high air pressure is reduced to a working pressure of 3-4 kgf / cm 2 and the air passes under the valve of the pulmonary automaton.

  During inhalation, the pressure in the tube and submembrane cavity A of the respiratory machine decreases, the membrane bends into the body, presses the lever 17, which in turn presses the lever 18, and the latter presses the dag on the stem A5, the valve departs from the saddle 19 and the air passes into the cavity A of the respiratory machine and further along the tube to inhale. When you exhale in the tube and submembrane cavity And creates an overpressure compared with the surrounding pressure, the membrane bends in the other direction, releases the levers 17 to 18 to the valve 15 under pressure of air coming from the gearbox 2, pressed against the saddle, the flow of air into the cavity of the lung machine is terminated.

  Simultaneously with the exhalation, the valve 20 opens and the air escapes through the rubber flap valve and the openings in the lid of the pulmonary machine to the outside.

  The operation of the AVM-3 breathing machine during inhalation and exhalation is similar to that of the A.BM-1M pulmonary automaton.

  In the case of increasing the air pressure in the chamber of the gearbox more than 5-8 kgf / cm 2, the safety valve 22 etches it out.

  The non-return valve 23 presses air pressure against the seat and closes the air outlet from the apparatus through the outlet nozzle, the hose.

  When the pressure in the cylinders drops to 45-30 kgf / cm 2, the spring 13, overcoming the pressure force of the air under the diaphragm, presses the diaphragm to the saddle through the spindle and the hard center and closes the orifice of the saddle. After that, the air to the gearbox passes only through the nozzle.

  The flow section of the nozzle does not provide a full inhalation, as a result of which the resistance on exhalation increases and the diver’s breathing becomes difficult. In this case, the diver must rise to the surface.

  To restore normal breathing, he manually opens valve 5, turning his handwheel a quarter of a turn. When turning the handwheel, the spindle rises, compresses the spring 13, freeing the hard center and the membrane, which, under pressure, bends the air and opens the seat. The amount of air per breath increases.

  The action of the device AVM-3 when the air supply through the hose from the surface. Before immersion, valves 4 and 5 are closed. To the inlet fitting 26 of the pulmonary machine attach the VS-1 diving hose (shown in Fig. 36 by a dotted line). Compressed air is fed into the hose from the surface, the pressure in which is maintained 1-4 kgf / cm 2 with excess pressure above the depth pressure.

  The air through the hose passes through the valve 23 to the valve 15 and, similarly to that described above, inhales. In case of interruption of the air supply, the diver manually opens the valve 4 on the cylinder through the hose, while breathing air from the apparatus cylinders.

  When air is supplied through the hose, the check valve 28 is pressed by air pressure to the saddle and closes 1 air passage into the cavity of the reducer 2.