RU2620733C1 - Automatic emergency closing of the crane of the gate of the gas pipe - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: machine contains a crane control system that includes a pneumatic actuator, a pressure gauge and a pneumatic cylinder housed in the body with a sensing element, a gas bypass element and a throttle assembly. The pneumatic cylinder is made in the form of a piston with an annular groove and is divided into two working cavities. One cavity of the pneumatic cylinder is connected with the gas pipeline, and the second - with the pressure comparison cavity formed inside the monolithic metal case into which the air cylinder is placed. The gas bypass element is made in the form of a single central through-hole of the piston in which a throttle assembly is mounted in the hub on the side of the cavity communicating with the gas line. The latter is executed in the form of successively coaxially installed two chokes, one of which is made in the form of a constant-section choke and faces the outer end of the piston, and the second is a slotted conical choke.

EFFECT: increase of reliability due to exclusion of false alarm of the device with simplification of design and reduction of overall dimensions and weight.

5 cl, 4 dwg

Description

The invention relates to valve engineering and can be used in the gas industry for the transportation of gases through gas pipelines to automatically shut off the gas pipeline in the event of possible gas breaks and leaks.

Known devices are automatic valve emergency shut-off valves (AAPC) of stop valves of the main gas pipeline, including a device for controlling the drive of a shut-off element in a gas pipeline and sensors that respond to a change in the pressure drop rate or to a change in the gas flow rate,

as domestic development:

- copyright certificate SU No. 189271 "Automatic machine for controlling the shutdown of the gas pipeline in case of damage", priority date 08/03/1961,

- copyright certificate SU No. 1048219 "Device for emergency shutdown of the pipeline", priority date 09/04/1981,

- SU patent for the invention No. 1712718 "Device for blocking the pipeline", priority date 10/31/1989,

- SU patent for the invention No. 1787228 "Automatic shutdown of the gas pipeline when it is damaged", priority date 04.04.1991,

- RU patent for the invention No. 2029191 "Automatic shutdown of the gas pipeline when it is damaged", priority date 04/29/1992,

- RU patent for the invention No. 2138720 "Automatic pipeline emergency shutdown", priority date 07/14/1998,

- RU patent for the invention No. 2208730 "Automatic emergency shut-off valve on gas pipelines", priority date 01/03/2001,

and foreign development:

- DE patent for the invention No. 3114359 "Protective device for gas installations", priority date 04/09/1981,

- DE patent for invention No. 3818859 "Safety shut-off device", priority date 06/03/1988

Also known is the emergency crane closing machine manufacturer JSC "Ufa Instrument-Making Production Association", http://www.uppo.ru/production/nefteprod/aazk/, accessed June 29, 2016; Journal "Territory Neftegaz", No. 5, 2008, p. 54-56, Internet link http://www.neftegas.info/upload/uf/aal/aalf5fle78e0be173a3c94eb77254 04f.pdf, accessed June 29, 2016. The machine contains a pilot, a pneumatic actuator control unit, a distributor and a lever. All nodes of the device are located on the stove and closed by a casing. The pilot AAZK is designed to issue a mechanical impulse to the lever at an emergency rate of pressure drop in the gas pipeline. The lever is mechanically connected to the block of levers of the pneumatic hydraulic actuator control unit. The pilot of the emergency crane closing machine contains a pneumatic cylinder, a distributor, a rod with a pusher. On the body of the pneumatic cylinder there is a control valve, a calibration valve and shut-off valves.

Also known machine emergency shutdown of the crane described in patent RU for invention No. 2238468. The machine contains a distributor with a spool in the form of a piston installed in its housing, the first and second control chambers connected to the gas pipeline, in which a shut-off element connected with the hydraulic actuator is installed. The piston is installed in the housing between the first and second control chambers and is mounted on a stepped rod with an annular groove. The length of the latter is equal to the distance between the hole in the casing connecting to the tank for emergency gas supply and the opening in the casing connecting to the valve closing valve connected with the shut-off element in the gas pipeline. In this case, the first control chamber is located under the lower end of the cover, and the second control chamber is under the piston. A protective cap is installed in the upper part of the housing, on which an explosion-proof switch is located.

Also known is an automatic emergency shut-off device (RU patent for the invention No. 2282088) containing a sealed chamber connected to the pipeline and the pneumatic cylinder with a piston and rod. The device is equipped with a throttle with a calibrated hole and a compensating pneumatic cylinder. At the same time, the second end of the rod is placed in the compensating pneumatic cylinder, freely communicating with the pipeline. The sealed chamber communicates with the pipeline through a throttle with a calibration hole.

However, the imperfection of the latter devices described above is cumbersome both in size and weight, which complicates their manufacture, increases the cost of materials, and also complicates delivery to the place of operation and use in the field. In addition, installation of the structures described above is not possible on a customer-owned drive with a control unit, since these structures cannot be interfaced with existing control units due to the presence of a stem in them.

The closest analogue to the claimed one is the emergency shut-off valve of the main gas pipeline described in RU patent for utility model No. 16024. The machine contains a pneumatic cylinder, divided by a sensing element into working cavities, and a comparison cylinder. One cavity of the pneumatic cylinder is in communication with the gas pipeline and the drive of the stop valves, and the other with the reference cylinder. The sensing element is made in the form of a piston with an annular groove and a rod kinematically connected with the mechanism for opening the tap of the gas supply line to the shutoff valve actuator. Bypass ducts are installed in the piston with check valves installed in them, two of which connect the working cavities of the pneumatic cylinder in different directions, the check valve of one of them having a calibrated (throttling) hole, and the third one of the cavities of the pneumatic cylinder with a space formed by the annular piston groove with the walls of the pneumatic cylinder.

However, the closest analogue also has a rather cumbersome performance. In addition, this design, as described above, is not protected from false positives.

The task of the invention is to increase reliability by eliminating false alarms of the device while simplifying the design and reducing the size and weight.

The essence of the claimed invention lies in the fact that in the automatic valve shut-off valve (AAPC) of the stop valve of the main gas pipeline containing a valve control system including a pneumatic actuator, a manometer and a pneumatic cylinder with a sensing element, a gas bypass element and a throttle assembly, the pneumatic cylinder of which is made in in the form of a piston with an annular groove and is divided internally into two working cavities, while one cavity of the pneumatic cylinder is in communication with the gas pipeline, and the second with the comparison cavity pressure, a pressure comparison cavity is formed inside the monolithic metal case into which the pneumatic cylinder is placed; the gas bypass element is made in the form of a single central through-hole of the piston, in which a throttle assembly is installed in the sleeve from the side of the cavity in communication with the gas pipeline, which is made in the form of two chokes installed in series coaxially, one of which is made like a constant-flow choke and faces the outer end of the piston, and the second is a slotted conical throttle.

An emergency shut-off valve for the stop valves of the main gas pipeline is also declared, in which, along with the above-described features, the constant-flow inductor has a recess for fitting and the insertion of a slotted conical inductor.

In addition, an AAZK with the aforementioned features is also claimed, in which grooves for the passage of gas are made on the conical portion of the slotted conical choke.

An emergency shut-off valve for the stop valves of the main gas pipeline is also declared, in which, along with the above-described features, technological holes are made on the sides of the monolithic metal case for forming cavities in it and are rigidly locked flush with plugs.

In addition, the AAZK is also claimed, in which the case is made of monolithic steel.

The technical result consists in the fact that the claimed device provides improved characteristics in comparison with analogues:

- reliability (eliminates false triggering of the machine),

- life time,

- simplicity and versatility (the possibility of compatibility).

One of the differences of the claimed design is the use of a throttle assembly to protect against false positives of the machine. The resistance to gas flow through two chokes, one of which is slotted, is small at a low gas velocity through them and increases significantly with increasing speed. This leads to a pressure difference in the working cavities, due to which the piston moves in the direction of the cavity connected to the gas pipeline, which in turn opens the gas passage from the receiver - usually this is an emergency gas supply cylinder (see Fig. 3) through the annular groove of the piston and further to close the drive of the locking element.

In addition, a number of the acquired technical properties mentioned have been achieved by a maximally thought-out arrangement of almost all the nodes due to the ability to place the composite nodes inside in a monolithic building. The size of the claimed emergency shutdown machine in comparison with analogues, including the closest, best to date, is much smaller. The reduction in size was achieved primarily due to the miniature sensitive element and the implementation of the pressure comparison cavity inside the common housing - the pilot with the sensitive element.

Allowed to carry out this arrangement, which led to the facilitation of the serviced gas line of the equipment, both in weight and in dimensions, a number of design methods aimed both at improving each of a number of nodes, and at choosing a new spatial orientation of each of the nodes of the claimed device relative to others ( see further explanations on the description text in the sections describing the claimed device in statics and dynamics).

The claimed technical solution is presented in FIG. 1-4, where the positions 1-20 indicate the nodes and parts:

FIG. 1 - General view of the pneumatic cylinder in the housing,

FIG. 2 - General view of the piston,

FIG. 3 - connection diagram of the AAZK to the main pipeline,

FIG. 4 - photo of the prototype,

1 - pneumatic actuator,

2 - pressure gauge,

3 - pneumatic cylinder,

4 - gas bypass element,

5 - throttle assembly,

6 - housing

7 - comparison cavity,

8 - piston

9 - annular groove,

10 - sleeve

11 - tip

12 - inductor constant cross-section,

13 - slotted conical choke,

14, 15 - plug hole,

16 - outlet fitting to the gas pipeline,

17 - fitting output to the pneumatic actuator,

18 - fitting output to the receiver,

19 - receiver

20 - grooves

working cavity A,

working cavity B.

The emergency shut-off valve is designed to issue a pneumatic signal to close the pneumatic actuator 1 at an emergency rate of pressure drop in the gas pipeline. The machine contains a crane control system, which includes a pneumatic actuator 1, pressure gauge 2. In addition, the AAZK has a pneumatic cylinder 3, which has a sensing element in the form of a piston with an annular groove and a gas bypass element 4 and with a throttle assembly 5. The pneumatic cylinder 3 is placed in the housing 6, in which a comparison cavity of 7 gas pressures is made. Comparison cavity 7 pressure was not located in the housing 6, and was performed in the form of a separate cylinder connected to the sensitive element by a small section pipe or hose. The pneumatic cylinder 3 is divided by the piston 8 into two working cavities, while one working cavity A is in communication with the gas pipeline, and the working cavity B is connected with a comparison cavity of 7 pressures. The piston 3 has an annular groove 9, and a gas bypass element 4 is placed in it in the form of a single central through hole with a throttle assembly 5 installed in it from the working cavity A of the sleeve 10 with two throttles and a nozzle 11 installed in series with it. One throttle 12 is made as a constant section choke 12, which faces the outer end of the piston 8, and the second 13 as a slotted conical throttle 13. The pneumatic cylinder 3 is bounded on both sides by plugs 14, 15, which are simultaneously limiters of the piston stroke, when it is horizontally extended in the upper part of the housing 6. On the housing 6 are the outlet fitting to the pneumatic actuator 17 and the outlet fitting 18 to the receiver 19. The outlet fitting to the gas pipeline is screwed into the plug of the pneumatic cylinder 14. A pressure gauge 2 is located on the front side of the housing 6 and is connected to the comparison cavity of 2 pressures. On the conical section of the slotted conical choke 13, grooves 20 are provided for the passage of gas. The working position of the housing 6 is vertical, while all fittings 16, 17, 18 are located in its upper part.

The device operates as follows.

During normal operation of the pipeline, the rate of change in the pressure of the working gas usually does not exceed (0.5-1.5) atm / min (the technological rate of pressure drop), and when the pipeline ruptures, the rate of drop in gas pressure increases significantly.

The side of the piston 8 of the pneumatic cylinder 3, limited by the plug 14, is under the direct pressure of the working gas from the main gas line, which flows through the outlet fitting to the gas line 16. The other side of the piston 8 is constantly under the gas pressure from the working cavity A, connected to the comparison cavity 7, which is slowly it is filled and emptied through the gas bypass element 4 in the form of an axial bore of the piston and a throttle assembly 5, placed in the sleeve 10 and consisting of a tip 11, a constant-flow inductor 12 and a slit hole conical throttle 13.

If the rate of gas pressure drop in the pipeline is within those values that are typical for normal operation of the pipelines (technological rate of pressure drop), AAZK does not respond to this.

The gas pressure drop in this case in the pneumatic cylinder 3 is negligible, and the position of the parts in the AAZK does not change.

When the pressure drop rate equal to or higher than the emergency pressure drop rate, the pressure from the side of the piston 8, limited by the plug 15, drops much faster than the pressure from the other side of the piston 8. Thus, a pressure difference is created, as a result of which the piston 8 of the pneumatic cylinder 3 moves all the way to the plug 14. As a result, an emergency supply of gas from the receiver 19 through the nozzle 18, the annular groove 9 of the piston 8 and the outlet fitting to the pneumatic actuator 17 enters the pneumatic cylinder of the actuator 1, ensuring its operation to close the cr on the main gas pipeline.

After the device is activated, the pneumatic cylinder of the pneumatic actuator 1 remains under pressure until repair work on the gas pipeline is completed.

When the gas pressure appears in the pipeline, the piston 8 moves all the way into the plug 15 and the comparison cavity 7 is slowly filled through the gas bypass element 4.

The level of pressure change in the comparison cavity 7 is numerically evaluated using a pressure gauge 2.

Example

In accordance with the claimed technical solution was made a prototype AAZK (Fig. 4). The prototype device has a mass of about 7.5 kg with dimensions of 170 × 155 × 50 mm. The device operates on the energy of the pressure of the transported gas, the operating pressure range from 3.5 to 10 MPa. The output signal for the operation of the AAZK is the rate of gas pressure drop in the gas pipeline from 0.05 to 0.06 MPa / s.

The inventive device is resistant to vibration in the frequency range from 5 to 80 Hz with an offset amplitude of 0.1 mm for a frequency of up to 60 Hz, with an acceleration amplitude of 9.8 m / s ² for a frequency above 60 Hz.

AAZK maintains its operability under seismic conditions up to 9 points on a 12-point scale of seismic intensity MSK-64 (according to GOST 30546.1).

The claimed and industrially manufactured design of AAZK is intended for operation including in difficult field conditions as climatic (at temperatures from + 40 ° C to -60 ° C in the Russian North and Siberia, as well as in the desert and semi-desert zone of the Caspian region) and unpredictable conditions of technological disasters.

Claims (5)

1. An emergency shut-off valve for a gas line shutoff valve comprising a valve control system including a pneumatic actuator, a pressure gauge and a pneumatic cylinder with a sensing element, a gas bypass element and a throttle assembly, the pneumatic cylinder of which is made in the form of a piston with an annular groove and is divided inside into two working cavities, while one cavity of the pneumatic cylinder is in communication with the gas pipeline, and the second with the pressure comparison cavity, characterized in that the pressure comparison cavity is grammed inside the monolithic metal body, which is placed in the air cylinder; the gas bypass element is made in the form of a single central through-hole of the piston, in which a throttle assembly is installed in the sleeve from the side of the cavity in communication with the gas pipeline, which is made in the form of two chokes installed in series coaxially, one of which is made like a constant-flow choke and faces the outer end of the piston, and the second is a slotted conical throttle. 2. The machine according to claim 1, characterized in that the constant-flow choke has a recess for fitting and the insertion of a slotted conical choke. 3. The machine according to claim 1, characterized in that on the conical section of the slotted conical choke grooves are made for the passage of gas. 4. The machine according to claim 1, characterized in that on the sides of the monolithic metal case there are technological holes for forming cavities in it and are rigidly locked flush with plugs. 5. The machine according to claim 1, characterized in that the housing is made of monolithic steel.

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