Air distributor

Compressed air flows from the brake line to the brake cylinders under pressure, which reduces the pressure in the line. The air diffuser is characterized by the rate of pressure reduction in the brake line. In the tempering position and charging, the air distributor allows pressure reduction at a rate of 0.02-0.04 MPa / min. without actuation (except for the air distributor of a rigid type of special purpose). For braking, it is necessary to reduce the pressure at a rate above 0.006 MPa per second by at least 0.03 MPa. To obtain maximum pressure in the brake cylinder, the brake line is discharged by 0.13–0.15 MPa. The air distributor quickly operates in a train of any length due to the additional service discharge of the line to a limited pressure (0.03–0.05 MPa) in the initial braking period; while overlapping charging holes. Further action of the air distributor is provided at any rate of reduction of the main pressure. Additional discharge of the line provides a high response speed of auto-brakes along the length of the train (up to 300 m / s for emergency and up to 280 m / s for service braking). An air distributor is installed on each unit of rolling stock.

The cargo air distributor 483 , which is an improved version of the already widely replaced air distributor 270 , can operate in plain and mountain modes (it provides stepless, that is, immediately full, or stepwise release of brakes, respectively), as well as in empty, medium and loaded modes for braking with different pressure in the brake cylinders of cars with different loading. Switching the operating modes of the cargo air distributor is done manually, the tempering mode - with the handle from the end of the main part, the braking mode - with the handle on the two-chamber tank. Between the cargo air distributor and the brake cylinder, it is possible to set the cargo auto mode that automatically adjusts the pressure in the brake cylinder depending on the load of the train, while the mode switch is fixed in the “loaded” position (with cast-iron brake pads) or “medium” (with brake pads made of composite material ) The cargo air distributor has a trunk and main parts mounted on a two-chamber tank . Through the main part it will be supplemented, discharge of the line during braking and rarefaction of the spool chamber in accordance with a decrease in pressure in the line. When the brake is released through the main part, the working chamber communicates with the spool chamber and the trunk (on the flat mode) or through the spool chamber only with the trunk (on the mountain mode). The main part stops the additional discharge of the line after a pressure drop of 0.05 MPa , fills the brake cylinder from the spare tank to a pressure corresponding to a decrease in pressure in the spool chamber and the force of the operating springs. When the brake is released, compressed air is released from the brake cylinder through the main part. Cargo air distributors used on foreign rolling stock have only one type of vacation: stepwise (on European railways) or stepless (on American railways).

Passenger air distributors 292 and 242 are designed for passenger rolling stock having operating modes that differ in the time for filling the brake cylinders during emergency braking and the release time of the brakes for short and long trains. Structurally, the passenger air distributor is made integral with the emergency braking accelerator. When braking, the passenger air distributor connects the brake line to the additional discharge chamber, causing a rapid decrease in pressure by about 0.025 MPa, and equalizes the pressure in the spare tank and line, bypassing the air into the brake cylinder. When the pressure in the line increases by 0.015–0.020 MPa after service braking, the main body of the passenger air distributor switches to the “vacation” position; while the brake cylinder communicates with the atmosphere, and the spare reservoir through the charging holes - with the brake line. With a rapid decrease in pressure in the line (at a rate greater than 0.05 MPa in 1 s), an emergency braking accelerator is activated, as a result of which the line communicates with the atmosphere. In foreign practice, passenger air diffusers with a different operating principle are used, made separately from the emergency braking accelerator.

Electrically operated air distributor used in rolling stock electro-pneumatic brake systems. The electric air distributor changes the pressure of the compressed air in the brake cylinders and maintains it within the required limits in accordance with the commands of the electrical signals from the control panel. Depending on the electro-pneumatic brake system, electric air distributors are distinguished:

• direct - acting type, acting directly on brake cylinders (used on domestic railways, on the subway (condition. No. 337) and in the USA)
• indirect type, controlling the change in pressure in the brake line (used in Western Europe).

On domestic electric trains, an electric air distributor has been installed since 1947 . Extensive studies of the electro-pneumatic brake with an electric air distributor in freight trains were carried out in the 60s. All passenger cars and locomotives, as well as cars of electric trains, diesel trains, high-speed trains, are equipped with an electric air distributor. Structurally, the electric air distributor is made in the form of a prefix to the pneumatic air distributor (for example, on electric trains and diesel trains) or as an independent device working with electric and pneumatic control - on high-speed trains. The conversion of an electric signal into a pneumatic one is carried out by electromagnetic valves. According to the method of signal conversion, electric air distributors are distinguished:

• analog type, acting in proportion to the time of supply of the electric signal (in the electric air distributor installed on passenger rolling stock, electric trains and high-speed trains) or acting in proportion to the change in the voltage of the electric current (with replacement valves, in the electrodynamic brake)
• discrete type (electric air distributor of the Westcode system on foreign rolling stock).

The chamber of the electric air distributor, mounted together with a pneumatic air distributor, is attached to the flange of the brake cylinder or to a special bracket through which the air ducts from the reservoir and the brake cylinder pass. The chamber cavity of 1.5 liters is the control tank of the pneumatic relay. The electric part of the electric air distributor contains two electromagnetic valves: brake and holiday. When braking, both valves are activated. The brake valve fills the control tank with compressed air, and the holiday valve disconnects the tank from the atmosphere. The required braking stage is determined by the excitation time of the brake valve. When the brake is released, both valves are de-energized, as a result of which compressed air is released from the control reservoir through the release valve, and the required release stage is determined by the time of its de-energization. Depending on the pressure change in the control tank of the pneumatic relay, containing the inlet and outlet valves controlled by the diaphragm, it carries out a similar pressure change in the brake cylinder, letting in compressed air from the reserve tank or releasing it into the atmosphere. To turn off the air distributor under the action of the electric air distributor, use the switching valve, which also turns off the electric air distributor when the air distributor is in action.

• Rail transport: Encyclopedia / Ch. ed. N. S. Konarev . - M .: Big Russian Encyclopedia , 1994. - S. 68. - ISBN 5-85270-115-7 .