RU2483342C1 - Reducing device - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: reducing device includes a gas pressure regulator, a cutout valve with air boost in an inlet channel, a safety valve in an outlet channel, which is connected through a throttle to a drain and a piston of the inlet and drain unloading valves consisting of a cutout valve; at that, in the cage with two shoulders there arranged is the inlet and drain unloading valves, which are detached from each other with a spring till they are borne against shoulders; the cage is connected through pushers to a piston and a return spring.

EFFECT: economy of gas reserves in an inlet line, avoidance of parasite high-pressure gas consumption from the inlet line to a drain, reduction of noise level and vibrations at operation of pneumatic systems, in which a reducing device is installed.

4 dwg

Description

The invention relates to the field of pneumatic automation and can be used for automatic control of gas pressure, mainly in pneumatic systems with increased requirements for vibration and noise characteristics.

Known gas pressure regulator according to the author's certificate of the USSR No. 1156025 class. G05D 16/10 (prototype) containing a direct-acting shut-off valve in the inlet channel, i.e. without pneumatic reinforcement. In the output channel of the regulator there is a safety valve, the output channel of which is connected to the drain through the throttle and to the control piston of the shut-off valve directly connected to the shut-off valve of the input line.

The disadvantage of this regulator is the significant weight and size characteristics of a direct-acting shut-off valve, especially with a low control pressure on its piston.

This disadvantage is eliminated when using the shut-off valve in the reduction device, which is given in the book “Devices and units of pneumatic automation of starting complexes. Designs and characteristics ”, Arzumanov Yu.L. and others, Kovrov, KSTA, 1999, p. 57.

The specified shut-off valve is made according to the scheme with pneumatic reinforcement and contains inlet and drain relief valves, which allows to reduce weight and size characteristics.

The disadvantage of this shut-off valve is the presence of gas flow from the inlet to the drain through the discharge valve in the intermediate position of the valve. This is especially manifested in the case of a gradual increase in the outlet pressure and partial opening of the discharge valve, when the so-called “freezing” of the valve occurs and the inlet channel is connected to the drainage, while there is a long parasitic gas flow from the inlet to the drainage.

The consequence of this flow is the noise and vibration that occurs in the reduction device and transmitted to neighboring elements of the system.

A reduction device containing a gas pressure regulator is proposed in the inlet channel of a shut-off valve with pneumatic reinforcement, and in the outlet channel a safety valve. The shut-off valve contains discharge inlet and drain valves that provide pneumatic reinforcement functions. The outlet channel of the safety valve is connected to the drain through the throttle and to the piston of the inlet and drain relief valves in the shut-off valve.

The proposed reduction device is distinguished by the fact that a clip with two shoulders is provided, in which an inlet and drain relief valves are placed, pressed against each other by a spring against the shoulders. An additional cage stroke is provided, providing a closed position of the inlet and drain relief valves in the intermediate position of the cage during the actuation of the shut-off valve.

The technical effect of using the invention consists in eliminating the parasitic flow of high pressure gas from the inlet line to the drainage and in reducing the noise level and vibration of the pneumatic systems. The exclusion of parasitic gas flow and noise in the form of hissing or whistling when the gas flows from the inlet to the drainage is ensured by the simultaneous shutdown of the inlet and drainage discharge valves as part of the shut-off valve in the transient processes of its operation.

The reduction of noise and vibration during the operation of pneumatic systems is ensured by the exclusion of prolonged gas flow into the environment during a smooth change in pressure in the system.

The drawings depict the proposed reduction device.

Figure 1 shows a General view of the reduction device.

Figure 2 shows the initial open position of the relief valves in the shut-off valve at an outlet pressure not exceeding a predetermined value.

Figure 3 shows the intermediate position of the relief valves in the process of smoothly increasing the adjustable pressure.

Figure 4 shows the closed position of the relief valves at an outlet pressure exceeding a predetermined value.

The proposed reduction device consists of a gas pressure regulator 1, a shut-off valve with pneumatic reinforcement 3 is installed in the inlet channel 2, and an outlet for drainage is installed from the outlet channel 4, in which a safety valve 5, which is part of the gas pressure regulator 1, is installed.

The shut-off valve 3 contains a main valve 6 with a pneumatic actuator 7, unloading inlet 9 and drainage 10 valves placed in a holder 11 having shoulders 12, 13. Unloading inlet 9 and unloading drainage 10 valves are pressed from each other by a spring 14 until they stop against the shoulders 12, 13. The holder 11 is connected by pushers 8 to the piston 15 and to the return spring 16. There is an additional stroke A of the holder 11, which provides in the intermediate position a simultaneous closed position of the inlet 9 and drain 10 of the discharge valves. In this case, the full stroke of the cage B is equal to the sum of the strokes B of the inlet valve, D of the drain valve and the additional stroke A. The inlet channel 17 of the inlet discharge valve 9 is connected to the inlet channel 18 of the main valve. The output channel 19 is connected to the cavity of the pneumatic actuator 7 of the main valve, the drainage channel 20 of the discharge valve 10 is in communication with the environment.

The gas pressure regulator 1 contains a pressure reducing valve 21, connected through pushers to the safety valve 5, with the sensing element 22 and the load spring 23. The spring 24 is installed in the direction of squeezing the safety valve 5 from the sealing surface of the sensing element 22. The adjusting screw 25 is designed to preload the load spring 23.

The output channel 26 of the safety valve 5 is connected through a throttle 27 to the drain and to the piston 15.

The reduction device operates as follows.

In the initial position, when high pressure is applied to the inlet channel 18 of the shut-off valve 3, the discharge valve 9 is open. The pressure through the channels 17, 19 falls on the pneumatic actuator 7, opening the main valve 6. Gas through the channel 2 enters the pressure regulator 1, the pressure reducing valve 21 of which in the initial position is opened by the load spring 23, and the safety valve 5 is closed. In the output channel 4, a low adjustable pressure is set in accordance with the setting force of the load spring 23 with the adjusting screw 25.

When the adjustable pressure rises above a predetermined value, for example, due to the tightness of the pressure reducing valve 21 or the temperature increase in the closed output volume with the pressure reducing valve 21 closed, the load spring 23 is compressed and the sensor 22 rises under the influence of increased pressure.

When this opens the safety valve 5 and discharges excess gas from the outlet cavity into the drain through the throttle 27. The opening of the safety valve 5 when lifting the sensing element 22 is due to the spring 24, squeezing them from each other.

When the gas flows into the drain through the throttle 27 in the control cavity of the piston 15, pressure appears on the principle of a flow cavity. In this case, the greater the flow rate and the larger the cross section of the open safety valve 5, the higher the pressure in the control cavity of the piston 15.

At a certain pressure on the piston 15, the force of the return spring 16 is overcome and the cage 11 is moved. Its movement can be considered in three stages.

In the first step, the moving parts move from the starting position indicated in FIG. 2 to the intermediate position shown in FIG. 3. In this case, the holder 11 moves together with the inlet discharge valve 9 by the amount of stroke B. At the end of the stroke, the inlet discharge valve 9 and the drain relief valve 10 are closed. A gap A remains between the shoulder 13 and the stop of the drain relief valve 10.

At the second stage, the cage 11 is moved by the size of the additional stroke A until the shoulder 13 contacts the drain relief valve 10. At the same time, the inlet 9 and drain 10 of the discharge valves remain closed. The flow of gas from the inlet to the drainage channel 20 is excluded.

In the third stage, the moving parts are moved to the position indicated in figure 4. In this case, when the inlet discharge valve 9 is closed, the clip moves together with the drain discharge valve 10, opening it to travel G.

When the drain valve 10 is opened, the gas pressure is drained through the drain channel 20 from the control cavity of the pneumatic actuator 7 and the main valve 6 is closed. The pressure on the gas pressure regulator 1 is stopped. Excessive pressure at the outlet of the gas pressure regulator 1 is vented from the channel 26 through the throttle 27 into the drainage.

As a result, the pressure on the piston 15 drops. The moving parts move in the reverse order to the case that occurs when the output pressure rises, i.e. closing the drain relief valve 10, opening the inlet discharge valve 9 and opening the main valve 6.

First, the unloading drain valve 10 is closed by the amount of stroke G. Then there is an additional stroke of the cage 11 in the course of A and opening of the inlet unloading valve 9 to the stroke B. In this case, in all intermediate positions there is no gas leakage from the entrance to the drain.

After opening the inlet discharge valve 9, gas from the inlet through the channels 17, 19 is supplied to the control cavity of the pneumatic actuator 7. The main valve 6 opens. The output of the gas pressure regulator 1 sets the set value of the output controlled pressure.

If the reason for the increase in the controlled pressure is not eliminated, the pressure reducing device works with the periodic closing and opening of the shut-off valve 3. However, there is no gas loss from the output line, since there is no “freezing” of the inlet and drain relief valves in the intermediate position, due to that in all transient response of the shut-off valve 3, the input channel 17 is disconnected from the drainage channel 20.

Here is an estimated calculation of gas savings in the input line when using the proposed reduction device instead of the known one. Consider the case of "freezing" of the discharge valve in the analogue, with a smooth increase in the regulated pressure above the set value. The calculation is based on the condition that a long steady-state flow through the throttle appears in the reduction device with the safety valve partially open, and then the excess outlet pressure is released. In this case, the pressure on the sensitive element of the discharge valve does not fully open the drain valve and closes the inlet discharge valve. Valves “hang” and gas flows from the inlet line to the drain.

The calculation of the flow rate for the critical gas outflow (G) through the discharge valve is carried out according to the formula:

Where

µ = 0.82 — flow coefficient for the valve – seat pair;

F = 0.008 cm ² - flow section of the discharge valve;

R _I = 50 kgf / cm ² - gas pressure in the input line;

T = 293 K - gas temperature;

B _φ = 0.4 - gas parameters for the working medium (air);

With such costs, 27.6 kg of inlet air is lost in one hour, 662 kg per day, i.e. more than 6 cylinders with a volume of 400 liters with a pressure of 200 kgf / s ² .

In the proposed reduction device, these parasitic expenses are excluded.

Claims (1)

A reduction device containing a gas pressure regulator, a shut-off valve with pneumatic reinforcement in the inlet channel, a safety valve in the outlet channel, connected through a throttle to the drain and piston of the inlet and drain relief valves as part of the shut-off valve, characterized in that the inlet has two inlets and drain relief valves, squeezed from each other by a spring all the way into the shoulders, the cage is connected by pushers with a piston and a return spring.

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