RU2578765C2 - Safety device - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to a pipe fitting and is intended to serve in emergency operation systems and components of a large unit capacity with high energy parameters. Flow part of a safety device is shaped as a nozzle. In inlet pipe 2 there is a tapered portion of nozzle. In outlet pipe 3 there is an expanding portion of nozzle. In bulb stopper 4 there is a minimum nozzle section with diameter equal to calculated diameter of passage section of tap. Return device is integrated with a piston drive in one power cylinder 7 of double action. Working chamber 8 and working cavity 9 of return device are linked via through-channel 12 in differential piston 6 and connected with reset through pulse safety valve 14.

EFFECT: higher efficiency of protection of secure facility.

4 cl, 5 dwg

Description

The safety device relates to pipeline valves and can be used in the energy, chemical, gas, oil and other industries for emergency service systems and units of large unit capacity, with high energy parameters.

Known safety devices consisting of a main safety valve with high throughput and a pulse safety valve that controls the piston drive of the main valve (DF Gurevich, ON Shpakov. Pipeline fittings designer reference book. - L .: Engineering, 1987, p. . 181). When the pressure of the working medium in the protected object rises above the set value necessary for its normal operation, the pulse safety valve opens and directs the working medium to the piston drive of the main safety valve with a large throughput. Following this, the main safety valve opens and discharges the excess working medium from the protected object.

The disadvantages of the analog device are:

- low throughput of the shutter of the main safety valve (the value of the flow coefficient of the safety valve with a lifting shut-off element, depending on the design, is 0.5 ÷ 0.8);

- the impact on the body of the main safety valve of the overturning moment from the reactive force that occurs when the valve is activated requires reinforcing the fastening of the device to the armature being protected, to the support or to the foundation.

The disadvantages of the analogue are partially eliminated in the prototype, protected by patent SU 2600, IPC F16K 17/12; F16K 5/02, published on 03/31/1927. The safety device of the steam boiler includes a direct-flow plug valve for venting excess steam, the plug of which is connected through a screw converter with a piston drive and with a lever-cargo device. The piston drive of the crane is controlled by steam taken from a part of the steam boiler remote from the safety device.

The disadvantages of the prototype is the low efficiency of protection of the protected object, its high overall dimensions.

The claimed technical solution allows to increase the efficiency of protection of the protected object by a safety device while reducing its overall dimensions.

The stated technical problem is solved in a safety device, including a direct-flow plug valve for dumping excess working medium from the protected object, which contains the inlet and outlet nozzles and is connected through a transmission device with a piston drive from the working medium from the protected object and to the return device. The flowing part in the nozzles and in the plug is shaped according to the shape of the nozzle, while the nozzle tapering part is made in the inlet nozzle, the expanding part of the nozzle is made in the outlet nozzle, and the nozzle has a minimum nozzle section with a diameter equal to the calculated diameter of the tap passage. The return device is combined with a piston drive in one double-acting power cylinder, the working cavities of which are interconnected and connected to the discharge via a pulse safety valve. The master cylinder includes a smaller diameter drive cavity, a larger diameter return device cavity, and a differential piston. The pulse safety valve includes a lifting spring-loaded shut-off element equipped with an unloading piston, which forms an over-piston cavity in communication with the return chamber in the power cylinder and an under-piston cavity in communication with the drive cavity in the power cylinder. The diameter of the discharge piston is equal to the nominal diameter of the bore in the seat of the pulse safety valve.

The essence of the claimed device is illustrated by the drawings which depict: in FIG. 1 - the claimed device in the closed position; in FIG. 2 - section along aa; in FIG. 3 - the claimed device in the open position; in FIG. 4 - a section along BB; in FIG. 5 - pulse safety valve.

The inventive safety device includes a plug valve with a housing 1, inlet 2 and outlet 3 nozzles, a ball plug 4. The flowing part in the nozzles 2 and 3 and in the ball plug 4 is profiled in the shape of a nozzle, while in the inlet nozzle 2 a narrowing part of the nozzle is made, in the outlet nozzle 3 has an expanding part of the nozzle, and in the ball plug 4 a minimum nozzle cross-section is made with a diameter equal to the calculated diameter of the tap passage. The shank of the plug 4 is connected via a transmission mechanism 5 to the differential piston 6 of the power cylinder 7. The power cylinder 7 includes a drive cavity 8 and a cavity 9 of the return device. The cavity 8 of the drive has a smaller diameter than the cavity 9 of the return device. In the cavities 8 and 9, thrust rings 10 and 11 are installed for the differential piston 6, which is a combination of two pistons of different diameters, combined into one part. Cavities 8 and 9 are interconnected through a channel 12 made in the body of the piston 6. The cavity 8 of the drive is connected by a pipe 13 with the inlet pipe 2 of the ball valve. At the end of the power cylinder 7, a pulse safety valve 14 is installed, which includes a lifting shut-off element 15, pressed against the seat 16 by a return spring 17. The shut-off element 15 is equipped with a discharge piston 18, which forms an over-piston cavity 20 in communication with the cavity in the inlet pipe 19 of the pulse valve 14. 9 in the power cylinder 7, and the piston cavity 21, in communication with the cavity 8 in the power cylinder 7. The diameter of the discharge piston 18 is equal to the nominal diameter of the bore in the seat 16 of the pulse safety valve ana 14. The actuator 7 is connected with the housing 1 the ball valve 22. Pulse counters relief valve 14 is connected to the power cylinder 7 bracket 23.

The inventive device operates as follows.

Configured for a given response pressure, with a closed ball valve, a safety device is installed on the protected object. The working medium from the protected object through the inlet pipe 2 and the pipe 13 enters the cavity 8 of the power cylinder 7 and through the through channel 12 in the piston 6 into the cavity 9. Due to the fact that the diameter of the cavity 9 and piston 6 in this cavity is larger than the diameter of the cavity 8 and the piston 6 in the cavity 8, the piston 6 is pressed against the thrust ring 10 and through the gear mechanism 5 holds the ball plug 4 in the closed position.

In case of an emergency increase in the pressure of the working medium in the protected object, the lifting locking element 15 of the pulse safety valve 14 overcomes the adjusted force of the return spring 17 and opens the passage section in the seat 16, as a result of which the working medium is discharged from the cavity 9 of the power cylinder 7 and the differential piston 6 moves to its the opposite extreme position, while turning the ball plug 4 to open the valve to discharge the working medium from the protected object. The excess working medium is discharged along the flow part of the tap in the form of a nozzle, while the internal energy of the working medium is converted into the kinetic energy of its directed movement. With an increase in the flow rate over the minimum nozzle section, the flow rate of the working medium through the device increases.

Due to the equality of the diameter of the unloading piston 18 to the nominal diameter of the bore in the seat 16 after depressurization from the cavity 9 of the power cylinder 7 and from the over-piston cavity 20 of the pulse safety valve 14, the differential piston 6 maintains its position until the pressure of the working medium in the protected object decreases and, accordingly, in the cavity 8 of the power cylinder 7 and in the piston cavity 21 of the pulse safety valve 14.

The inventive device closes after reducing the pressure of the working medium in the protected object, in the cavity 8 of the power cylinder 7 and in the cavity 21 of the pulse safety valve 14 below the setting pressure of the pulse safety valve 14. In this case, the differential piston 6 returns to its original position in the power cylinder 7, turning the ball plug 4 in the closed position.

The effectiveness of the inventive safety device is determined by its high throughput (performance) and the positive influence of backpressure, which unloads the shutter of a ball valve and reduces the friction moment in the shutter.

Claims (4)

1. A safety device, including a direct-flow plug valve for dumping excess working medium from the protected object, which contains the inlet and outlet nozzles and is connected via a transfer device with a piston drive from the working medium from the protected object and to the return device, characterized in that the flow part the nozzles and in the plug are shaped according to the shape of the nozzle, moreover, the tapering part of the nozzle is made in the inlet nozzle, the expanding part of the nozzle is made in the outlet nozzle, the minimum the nozzle cross section with a diameter equal to the calculated diameter of the tap passage area, and the return device is combined with a piston drive in one double-acting power cylinder, the working cavities of which are interconnected and connected to the discharge through a pulse safety valve. 2. The device according to p. 1, characterized in that the power cylinder includes a drive cavity of a smaller diameter, a cavity of the return device of a larger diameter and a differential piston. 3. The device according to claim 2, characterized in that the pulsed safety valve includes a lifting spring-loaded shut-off element provided with a discharge piston forming in the inlet pipe of the pulsed safety valve an over-piston cavity in communication with the cavity of the return device in the power cylinder, and a under-piston cavity, communicated with the drive cavity in the power cylinder. 4. The device according to p. 3, characterized in that the diameter of the discharge piston is equal to the nominal diameter of the bore in the seat of the pulse safety valve.

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