RU2633735C1 - Impulse safety valve - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: valve is proposed including a body with inlet and outlet connections and flanges, rod, bellows, spool, seat, setting spring, pressure bolt, upper and lower stops of the setting spring, additionally equipped with an independent opening-closing device consisting of springs, a pressure bar, a stop nut screwed onto the rod, and the lower spring stops, located on the pressure bar, pressure bolts inserted in the upper spring stops, located in the upper bar with the possibility of rotating it in the thread, jacks with operating environment for lift generation and with rods resting on the pressure bar. Disk-separator of pressure and discharge with saddle cavities and a filter. In the upper bar a hollow pressure bolt with the possibility of rotating it in the thread is additionally installed. The valve is mounted on a common base.

EFFECT: increase of reliability due to trouble-free and timely opening of the valve at a given excess of operating pressure in the system, providing the valve with an open position with the required capacity, making a timely return of the valve at pressure higher than the working pressure with the required degree of leakage after an emergency operation.

3 dwg

Description

The present invention relates to protective power fittings and is intended for use, both independently and as part of a pulse safety device (IPA) for protection against overpressure in pipelines, tanks, operating under pressure at thermal and nuclear power plants.

A safety valve is a valve designed to protect equipment from unacceptable pressure by relieving excess working medium and stopping the discharge at closing pressure and restoring working pressure. [Pipe fittings with automatic control: T77 Reference / D.F. Gurevich, O.N. Zarinsky, S.I. Kosykh et al. / Under the general. ed. S.I. Skew. - L .: Engineering, Leningrad. Otdel, 1982. - 320 p., ill. page 127-155.]

Mandatory components of the design of a direct-acting safety valve (PC) are a shut-off element and a setter, which provides a force action on the sensitive element associated with the shut-off valve element. The PC locking element consists of a shutter and a seat. The shutter (valve) is a locking element. When installing a PC in the system, certain ratios must be observed between the pressures of the working environment adopted in the protected installation and the pressures characterizing the various stages of the PC. Using the adjuster, the safety valve is adjusted so that the force on the spool ensures that it is pressed against the seat of the shut-off element and prevents the passage of the working medium through the shut-off element of the PC. The highest pressure at the inlet to the PC, equal to the operating pressure in the system, at which the required degree of tightness of the valve shut-off element is provided, is called the adjustment pressure Рн. Working pressure Pp is the highest pressure in the system at which a normal flow of the working process is ensured. In the closed position of the PC, its sensitive element is affected by the force from the working pressure in the protected system (setting pressure), which tends to open the PC, and the force from the setpoint, which prevents opening. A certain part of one of these efforts (depending on the design of the PC) is spent on pressing the spool to the seat and creating the necessary contact pressures in the shut-off body, providing the required degree of tightness of the PC.

With the occurrence of disturbances in the system that cause an increase in pressure above the worker, the magnitude of the force of pressing the spool to the saddle decreases. At the moment when this force becomes equal to zero, the balance of active forces comes from the action of pressure in the system and the setter on the sensitive element of the PC. The valve shutoff valve begins to open if the pressure in the system does not stop increasing. If the pressure in the system rises above the calculated one, the balance of forces on the sensitive element of the PC is violated, the shut-off element opens and the working medium is discharged through the valve.

With a decrease in pressure in the protected system, caused by the discharge of the medium through the PC, disturbing influences disappear. The valve closure is closed by force from the setpoint. Closing pressure Pz is the highest pressure at the inlet to the valve at which, after the medium is discharged, the shutter lands on the valve seat to provide the required degree of tightness of the shut-off element with a subsequent increase to the setting pressure. The closing pressure in some cases is 10-15% lower than the setting pressure. This phenomenon is partly due to the fact that to create the tightness of the locking element after actuation, a force is required that is much greater than that which was sufficient to maintain the tightness of the valve before opening. This is explained by the need to overcome when landing the cohesive force of the molecules of the medium passing through the gap between the sealing surfaces of the valve and seat, to displace this medium. A decrease in pressure is facilitated by the delay in closing the closure body, associated with the action of dynamic forces on it from a passing medium flow, and the presence of friction forces that require additional force to completely close it.

Impulse valves are classified:

According to the principle of action:

direct-acting valves - they open directly under the influence of the working medium pressure;

valves of indirect action - valves with control by using an external source of pressure or electricity.

By the nature of the lifting of the closing organ:

proportional valves; on-off valves.

According to the lifting height of the closing body:

low lifting (lifting of the closing body does not exceed 1/20 of the diameter of the saddle);

medium lifting (the lifting of the closing body is from 1/20 to 1/4 of the diameter of the saddle);

full-lift (lifting of the closing body is from 1/4 of the diameter of the saddle or more).

By type of load on the spool: freight or lever-freight; spring; lever spring; magnetic spring.

To date, a large number of safety valves have been created and used in technology. Different safety valves have different sizes, different values for switching on the discharge pressure and the landing pressure, as well as the discharge speed.

The main PC manufacturers are:

Blagoveshchensk Reinforcing Plant "BAZ" OJSC its products are safety valve SPPK4R 50-40 DN 50 mm, PN 40 kgf / cm ² .

http://www.vniiis.ru/pic/info/product_catalog_blagoveshchensk_valving_plant.pdf

Spring safety valves DN 25-200 PN 16-160 kgf / cm ² .

http://bm-stroy.ru/p116/index.html

LLC "BKZ" Barnaul - Safety lever valves 17ch3br, 17ch18br, 17ch5br, 17ch19br.

http://armabalt.ru/catalog/klapany_chugunnye_57/klapan_predokhranitelnyy_rychazhnyy_17ch3br/

OAO TKZ Krasny Kotelshchik Taganrog - Safety spring valve T-31 ms-1; T-31 ms-2; T-31 ms-3.

http://pek.su/services/oao-tkz-red-coppersmith/safety-valves/t-31-ms-3/

CJSC Energomash (Chekhov) - ChZEM Chekhov - direct-acting safety valves 586-20-EM-01.

http://armabalt.ru/catalog/klapany_impulsnye_predokhranitelnye/klapan_impulsnyy_predokhranitelnyy_586_20_em_01/

pulse valves 112-25x1-0M.

http://test.armabalt.ru/catalog/995/4430/ and other plants.

Source of information: [Official sites of factories, product catalogs, Gurevich David Fayvushev. Pipe Fittings: A Reference Guide. Ed. 3rd - M.: Publishing house LKI, 2008. - 368 p. p. 142-150; p. 261-270].

The closest in technical essence and the achieved result to the claimed one is the well-known safety valve SPPK4R produced by the Annunciation Armature Plant "BAZ" [http://www.vniiis.ru/pic/info/product_catalog_blagoveshchensk_valving_plant.pdf].

[Pipe fittings with automatic control: T77 Reference / D.F. Gurevich, O.N. Zarinsky, S.I. Skew and others; Under the total. ed. S.I. Skew. - L .: Engineering, Leningrad. Otdel, 1982. - 320 p., ill. p. 137.]

The specified safety valve, as claimed, contains a housing with inlet and outlet pipes and flanges, a rod, a locking member having a seat and a spool, a set spring, a spring pressure bolt, upper and lower spring stops.

The disadvantages of direct-acting PCs are:

1. Low valve seating after depressurization; in some cases, the closing pressure is 10-15% lower than the operating pressure (setting pressure).

2. The passage of the valve in the shut-off body at the operating pressure due to the fact that only a small part of the spring or load is spent on pressing the spool to the seat and creating the necessary contact pressure in the shut-off body. According to GOST 24570-81 (ST SEV 1711-79) (http://www.docload.ru/Basesdoc/8/8625/index.htm) the pressure difference between the full opening and the start of opening the valve must not exceed the following values: 15% pressure opening start - for boilers with operating pressure not higher than 0.25 MPa (2.5 kgf / cm ² ); 10% of the opening start pressure - for boilers with a working pressure above 0.25 MPa (2.5 kgf / cm ² ). Hence the conclusion: only about 10-15% of the total initial force of the spring or load is spent on pressing the spool to the seat.

Valid leakage on the shutter is summarized in GOST 9544-2015. http://standartgost.ru/g/%D0%93%D0%9E%D0%A1%D0%A2_9544-2015.

The technical problem solved by the invention is the creation of a reliable, trouble-free pulse safety valve.

The technical result from the use of the invention is to increase reliability due to failure-free and timely opening of the valve at a given excess of the operating pressure in the system, providing the valve in the open position with the required throughput, timely valve landing (closing) at a pressure higher than the working one with the required degree of tightness ( class A) after emergency operation.

The specified technical result is achieved in that the pulse safety valve, comprising a housing with inlet and outlet pipes and flanges, a rod, a bellows, a spool, a seat, a spring-setter, a pressure bolt, the upper and lower stops of the spring-setter, is additionally equipped with an independent opening device - closing, consisting of springs, pressure plate, thrust nut screwed onto the rod, and lower spring stops located on the pressure plate, pressure bolts inserted in the upper spring stops located in the upper a bar with the possibility of rotation in it along the thread, jacks with a working medium to create lifting force and with rods abutting against the pressure bar, while in the case there is a disk separator of cavities for pressure and discharge with a saddle and a filter, and in the upper bar an additional hollow a pressure bolt with the possibility of rotation in it along the thread, and the valve design is mounted on a common base.

The difference between the claimed PC and the prototype is the presence of an independent device in which the force from the action of the working medium for opening and closing the valve is many times greater than in the direct-acting valve (when acting on the spool). Accordingly, the force of the setpoint spring, which must be overcome by the device when the valve is opened, also increases proportionally in accordance with the force of the opening-closing device. To check the performance, electromagnets are installed. During operation, they are disabled.

The invention is illustrated in FIG. 1-3.

Brief Description of the Drawings:

FIG. 1 - section, front view.

FIG. 2 - section, right side view, tilted forward.

FIG. 3 is an isometric view from the front.

In the above drawings, an embodiment of the invention is shown.

In FIG. 1-3 with the inclusion of the valve in the piping system with the flow of medium to the spool.

The structure of the pulse safety valve includes:

common base 1 (metal structure on which the entire valve is mounted), housing 2. The valve consists of gaskets 3, 4, filter 5, bellows 6, spool 7, stem 8, disc separator 9 cavities: pressure head G and waste B, seat 10 of the separator disk 9.

The stud 11, nuts 12, 13 comprise the fastener of the valve connector. A jack 14 having a cavity B with a working medium, consisting of a bottom 15 of the bellows 16 and a stem 17, is installed on the base 1. Outside the valve, a thrust nut 18 and a lower stop 19 of the setpoint spring are installed. The lower stop 20 of the pressure plate 21 serves to limit the stroke of the pressure plate 21 down when setting the valve without a working medium. The lower emphasis 22 of the spring jack is located on the pressure plate 21. The spring-setter 23 abuts against the lower emphasis 19.

The spring 24 of the jack 14 abuts against the lower stop 22. The upper stop 25 is located on the spring-setter 23. The upper stop 26 is located on the spring 24 of the jack 14. The pressure bolt 27 of the spring 24 is inserted into the upper stop 26 to adjust the force of the spring 24. The lever 28 of the electromagnet with an anchor 29 and an electromagnet 30 with a thrust nut 31 serve to open the valve at any pressure in the circuit (pipelines, tanks) and to check the operability of the valve.

The hollow pressure bolt 32 of the setpoint spring 23 is installed in the upper stop 25. An electromagnet 33 with an armature 34, a lever 35, and electromagnet mounting bolts 36 are used to open the valve at any pressure in the circuit (pipelines, tanks) and to check the operability of the valve. The pressure bolt 37 is located in the upper bar 38 of the base 1. The stud 39, nuts 40, 41 make up the fasteners of the upper bar 38 to the base 1. The upper stop 42 is located on the spring 43. The stop nut 18 is screwed onto the stem 44 and the lower stop 19 is rigidly fixed to it setpoint spring 23. The lower stop 45 of the spring 43 is located on the pressure plate 21, under which the stop 46 is mounted. The stem 47, the bellows 48, the bottom 49 of the bellows form a jack 50 with a cavity A and with the working medium. The inlet pipes 51, 52, 53 and the inlet flange 54 are connected to the valve body 2 and the jacks 14, 50. The adjusting screw 55 is located on the base 1. The electromagnet 56 serves to open the valve at any pressure. Between the pressure plate 21 and the thrust nut 18 there is a gap - "S", to control the correct settings. A thread is made in the upper bar 38. The rods 17, 47 abut against the pressure plate 21. The hollow pressure bolt 32 of the setpoint spring 23 is mounted in the upper plate 38 with the possibility of rotation in it along the thread. The outlet flange 58 is connected to the valve body 2. Repair flanges 59, 60 connect the rods 8, 44. The axis of rotation of 61 levers 28, 35 is located on the electromagnets 30, 33, 56.

The jack consists of a housing, a bellows, a rod. The bellows performs two functions - it seals the atmosphere from the atmosphere and creates lift in the jacks.

The force created by the jacks depends on the pressure of the working medium and the effective area of their bellows (the effective area of the bellows is the area under the influence of which the pressure of the working medium causes a lifting force in the jack, approximately equal to the internal area of the bellows) and is calculated by the formula:

F = P _p × S _s

where R _p - working pressure;

S _c is the effective area of the bellows.

The effective area of the bellows in the design is not limited by anything and can have (take) any value. It follows from the formula that the force created by the jacks to open the valve can be many times greater than in a direct-acting valve, where the opening force is created by the pressure of the working medium on the effective area of the valve and in which the area of the valve, spring force, working pressure, opening pressure are interconnected and focused on the diameter of the saddle (inlet). The opening-closing device has a stepwise effect on the setpoint spring.

In the first position, at a working pressure P _p , there is no effect on the set spring. Between the pressure plate 21 and the stop nut 18, a clearance “S” is established, all the force of the setpoint spring (100%) is spent on creating contact pressures in the valve-seat pair, which completely eliminates leaks in the valve, unlike the direct-acting valve, in which at operating pressure, the spring force in the locking element is about 10-15%.

The second position - with increased pressure in the pipeline, capacity. The impact on the spring-setter is carried out by the rods 17, 47 of the jacks 14, 50 through the pressure plate 21 and the thrust nut 18 to compress and open the valve.

Due to the fact that in the inventive valve there is no rigid connection between the setpoint spring and an independent opening-closing device, the spring force in the designed valve is selected from the conditions of reasonable sufficiency (so as not to damage the sealing surfaces of the seat and spool) or according to the customer’s request, and according to it an opening-closing device is created. With an increase in the force of the device, with the same spring-setter, the pressure difference between the opening and complete opening of the valve decreases. The valve begins to open at a higher pressure, significantly higher than the worker, respectively, and its return pressure P _op at closing will be higher than the worker P _r due to the increased force of the setpoint spring.

Preset Pulse Relief Valve (Fig. 1-3)

Before putting the valve into operation, it is necessary to adjust the valve:

1. Press the set spring 23 with the hollow pressure bolt 32 to the force selected in advance when designing (calculating) the valve.

2. Tighten the springs 24, 43 with the pressure bolts 27, 37 to a force equal to that of the jacks at operating pressure.

The spring force is calculated by the formula:

F _CR = K _CR × _Δ L _CR

where K _CR - spring stiffness (kg / mm);

_Δ L _CR - the amount of compression of the spring (mm).

3. Set the clearance “S” equal to approximately 1-2 mm between the pressure plate 21 and the thrust nut 18 by rotating it along the stem 44.

The operation of the valve with the flow of medium to the spool (Fig. 1-3)

When connected to the piping system, tanks, the working medium through the inlet flange 54 through the inlet pipes 51, 52, 53 enters the cavity A of the jack 50, into the cavity B of the jack 14, into the pressure cavity G of the valve 2.

In cavities A, B at operating pressure, acting on the effective area of the bottoms 15, 49 of the bellows 16, 48, a lifting force is created in each of the jacks, which is equal in magnitude to the force of the springs 24, 43 pressed in the preset, which transfers through the rods 17 and 47 the force on the pressure bar 21, which lies on the stops 20, 46.

In the pressure cavity of the valve G, the working medium passes through the filter 5 to the bellows 6 and the spool 7, exerting pressure on the effective area of the bellows 6 to open and on the effective area of the spool 7 to close the valve (their areas are approximately equal to each other). Between the pressure plate 21 and the thrust nut 18 there is a gap "S" of about 1-2 mm. This is the operating condition of the valve.

Important notice. In this operating condition of the valve, all the effort (100%) of the setpoint spring 23 is spent on creating contact pressures on the sealing surfaces in the pair of spool 7-seat 10, sufficient to seal the shut-off element of the pulse valve, while in the direct-acting valve, working pressure is used only about 10-15%.

With increasing pressure in the pipeline, the capacity will increase the lifting force of the jacks 14, 50. This force is transmitted through the rods 17, 47 to the pressure plate 21, it begins to move up (towards the opening), compressing the springs 24, 43. The clearance “S” decreases and becomes equal to zero. The pressure bar 21 abuts against the thrust nut 18 and stops. With a further increase in pressure, the force of the jacks 14, 50 increases even more, and as soon as it exceeds the force from the springs 24, 43, the setpoint spring 23 and the force from the effective area of the spool 7, the valve will begin to open. Under the spool comes the working environment; the force pressing it to the seat 10 disappears (decreases to zero), and in addition to this, pressure begins to increase in the discharge cavity B, which acts on the spool 7 towards the opening. There is a difference of forces, big in the jacks. The system “in leaps” (in fractions of a second) is brought into equilibrium by moving the pressure bar 21 upward, compressing the springs 24, 43, the setpoint spring 23, lifting the thrust nut 18 together with the rods 8, 44, repair flanges 59, 60 and spool 7 up (towards the opening) opening the valve. The working medium passes into the discharge cavity B, then through the outlet pipe and flange 58 into the main safety valve or into the atmosphere. The magnitude of the stroke of the spool 7 depends on the stroke of the pressure plate 21 and is regulated by a screw 55 (another screw is not shown). After depressurization, the efforts of the springs 24, 43 return the pressure bar 21 to its stops on the stops 20, 46, and the spring-setter 23, due to the increased force, closes it as soon as the minimum clearance “S” appears even with an increased pressure of the medium.

To open and close the valve at any pressure in the pipeline, capacity and when checking its performance, electromagnets are installed on the valve. During normal operation of the valve, they are disabled.

Work from power electromagnets (Fig. 1-3)

When voltage (electric current) is applied to the electromagnets 30, 33, 56 (and one more is not shown in the figures), their anchors 29, 34 (and two more are not shown in the figures) begin to move downward, acting on the levers of the electromagnets 28, 35 (and two more are not shown in the figures), lowering them down. The other end of each lever through the axis of rotation 61 rises up, raising the thrust nut 31 and with it the upper part of the stem 44, the lower part of the stem 8 and the spool 7, compressing the set spring 23, opening the valve. When the power is turned off, the armatures of the electromagnets return to their original position. The valve is closed by the force of the spring-setter 23.

The valve is classified as a two-position full-lift with the ability to adjust the spool stroke with screws 55 (one not shown).

The valve can work with the medium flowing under the spool 7. All valve settings are the same except the force of the spring-setter 23. It (the spring-setter) must be pressed harder by the amount of force acting on it from the spool 7 at operating pressure. Its value will be:

F = P _p × S _s

where R _p - working pressure;

S _s - effective area of the spool.

In this case, the valve operates (classified) as a proportional valve (the greater the pressure, the greater the opening value) with the possibility of adjusting the stroke of the spool with screws 55, (one not shown).

Valve repair is carried out by replacing the defective part with a new one. In the device, up to each assembly unit there is free access, that is, to remove and put in a new part, you need a minimum of time and devices. Dismantling the valve to the seat and spool also does not require a lot of time. To do this, repair flanges 59, 60 are installed, having separated them, the valve itself can be removed from the entire IPC design with jacks, while the springs and electromagnets remain in place and cannot be disassembled, which subsequently reduces the time for repair and adjustment.

The proposed pulse safety valve can be made of standard parts manufactured by the industry.

Thus, the proposed pulse safety valve can improve reliability due to trouble-free and timely opening of the valve at a given excess of the working pressure in the system, providing the valve in the open position with the required flow rate, timely valve landing (closing) at a pressure higher than the working one, with the required degree tightness (class A) after emergency operation. In addition, the proposed valve is repairable.

Claims (1)

Pulse safety valve, comprising a housing with inlet and outlet pipes and flanges, a rod, a bellows, a spool, a seat, a set spring, a pressure bolt, upper and lower stops of the set spring, characterized in that it is additionally equipped with an independent opening-closing device, consisting of springs, a pressure plate, a thrust nut screwed onto the rod, and lower spring stops located on the pressure plate, pressure bolts inserted into the upper spring stops located in the upper bar rotatably I'm threaded in it, jacks with a working medium for creating lifting force and rods abutting against the pressure bar, while in the case there is a disk separator of the pressure and discharge cavities with a saddle and a filter, and an additional hollow pressure bolt is installed in the upper bar with the possibility of rotation in it is threaded, and the valve design is mounted on a common base.

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