RU2779683C1 - Breaking clutch - Google Patents

Abstract

FIELD: liquefied natural gas transportation.

SUBSTANCE: invention relates to devices of systems for overflow and transportation of liquefied natural gas and is intended for automatic disconnection of a stander with inlet and outlet pipes of pipelines in case of an emergency. A breakaway clutch is proposed, which includes two valves connected to each other by a clamp, a mechanical disconnector with a drive, each valve contains a main and an auxiliary body; a ball with a fluid passageway; two sealing circuits - primary and secondary, consisting of a group of springs, a ball-seat seal and a ring-seat seal of a different configuration for each circuit, pressed by means of a group of springs to the surface of the ball, ring and seat, having a different configuration for each seal circuit. In case of loss of tightness of the primary seal circuit in the closed position, the secondary seal circuit is designed to maintain the tightness of the breakaway clutch due to the pressing force arising due to the pressure difference on the end faces of the elements and the gaps between the elements of the seal circuit that are structurally provided.

EFFECT: increasing the reliability of the hermetic connection when the coupling is disconnected and increasing the service life of the device by introducing a second seal circuit and equipping the clamp latch with a shear pin, and the different design of the primary and secondary seals allows them to work sequentially - if the primary seal loses tightness, the secondary circuit is triggered.

7 cl, 10 dwg

Description

The invention relates to the oil and gas field, and in particular to devices for overflow systems and transportation of liquefied natural gas, in particular to docking stations of the stander.

The breakaway coupling is used in the emergency disconnection system and is designed to automatically disconnect the loader from the pipeline inlet and outlet pipes in the event of an emergency, for example, in the event of significant axial forces caused by the drift of the vessel.

State of the art

Known rupture coupling designed for emergency disconnection of pipelines, containing a shut-off valve, a connecting part, opening and closing valves, a pipeline separation mechanism to release the connection, a guide element attached to the pipeline and configured to be connected to the pipeline, a control unit for controlling the separation mechanism ( patent JP 2012184837, published on September 27, 2014).

The disadvantage of this device is the high vulnerability of the correct operation of the device due to the complex system of interaction between two hydraulic cylinders to disconnect the breakaway clutch. The first hydraulic cylinder rotates the pins of the ball valve disconnectors, and thereby closes them when the clamp opens under the action of the second hydraulic cylinder.

An element of the fluid transfer emergency stop system is also known (patent WO 2016182066 A1, publ. 03/19/2019). The system includes a body, a ball, an upper and lower stem, a sealing system with primary and secondary seals containing a clamping mechanism.

The disadvantage of this device is the high risk of depressurization of the secondary seal in the closed position, and as a result, the entire device, since the sealing system uses the same primary and secondary seals, made in such a way that the tightness of the secondary seal will be determined only by the force of the spring, which presses the ring to the seal , and if the force from the pressure on the ring exceeds the force of the spring, the seal will depressurize. When pressure enters the coupling cavity in the closed position when the primary seal is broken, the secondary seal is depressurized under the influence of pressure on the seat surface, since the force arising from the pressure acting on the seat exceeds the clamping force from the action of the spring.

Also, the disadvantage of the system is the difficult switching of the ball from the "Open" mode (passage of the fluid medium) to the "Closed" mode (shut off the flow of the fluid medium) due to the fact that the pressure is not balanced. This is due to the fact that the pressure from the passage diameter zone (product transportation zone) does not enter the internal cavity of the product and is not balanced. This reduces the resource of the device.

Closest to the claimed invention in terms of technical essence and the achieved result (prototype) is a device for emergency disconnection of a fluid pumping system (patent KR 101649796 B1, publ. 30.08.2016). The device makes it possible to close the valve in the breakaway sleeve when the fluid transfer device is in danger of malfunction due to external factors. The device consists of two ball valves connected to each other by a clamp, each of which contains a sealing circuit for shutting off the fluid flow. The operation of the sealing circuit in the ball valve prevents fluid leakage while preventing damage to the system by disengaging the coupling.

The disadvantage of this device is the high risk of depressurization of the sealing circuits of the ball valve in the closed position (shutoff of the fluid flow) in the event of an emergency disconnection of the valves due to the lack of a two-circuit protection system. Also, the disadvantages include a high risk of damage to the clamp and its possibility of engagement with the elements of the emergency release system due to the lack of stroke limitation.

Disclosure of the essence of the invention

The proposed breakaway coupling is used in offshore loading arms, which are used in loading and unloading operations of liquefied natural gas at sea / river terminals, providing connection of onshore pipelines with the inlet and outlet pipes of pipelines on the ship. The rupture coupling ensures the closure of the product channel in the event of an emergency rupture of the pipeline system.

The task of the breakable coupling is to increase the reliability of the hermetic connection when the coupling is disconnected and to increase the service life of the device.

The technical result consists in the joint and sequential operation of the two sealing circuits of each of the valves, which creates a double sealing barrier when the device is disconnected and increases the reliability of the tightness, as well as in reducing the loads when switching the valves to the closed position, which facilitates their switching and eliminates the possibility of ball misalignment ( jamming), thereby increasing the service life of the device.

The solution to the mentioned technical problem is achieved by the fact that in a breakaway clutch with a through passage for a fluid medium, which has two valves connected to each other by a clamp, a mechanical disconnector with a drive, which by means of a pusher ensures closing and disconnection of the valves of the breakaway clutch, according to the invention, each valve contains:

the main and auxiliary body located coaxially with an emphasis on the end and the possibility of fastening by means of a threaded connection;

a ball with a passage channel for fluid, connected to the main body by means of fixed and movable supports fixed in the seats of the main body, while the movable support through the trunnion mounted on it enters into conjugation with the pusher of the drive and performs rotational movement of the ball to block the passage channel;

two sealing circuits - primary and secondary, located in the seats of the main and auxiliary housings and consisting of:

groups of springs located eccentrically to the axis of the passage channel;

ball-seat seals and ring-seat seals of a different configuration for each circuit, pressed against the surface of the ball by a group of springs;

rings and seats, having a different configuration for each sealing circuit and located concentrically to the axis of the bore,

at the same time, in case of loss of tightness of the primary seal circuit in the closed position, the secondary seal circuit is made with the ability to maintain the tightness of the breakaway clutch due to the pressing force arising due to the pressure difference on the end faces of the elements and the gaps between the elements of the seal circuit that are structurally provided.

In the primary circuit, the gaps are located between the ring and the seat on one side and the ring and the auxiliary body on the other, and in the secondary circuit the gaps are located between the seat and the main body on the one hand, and the seat and ball on the other.

In the open position (during the passage of the product), the primary and secondary seal circuits allow sealing of the connection by pressing the ball-seat seal against the ball due to the transfer of force from a group of springs, and in the primary seal, the possibility of sealing is simultaneously ensured by the force arising from the pressure difference on the end surfaces rings in the provided gaps between the ring and the seat on one side, and the ring and auxiliary body on the other side.

In the closed position of the device (when the fluid flow is shut off), the seal circuits work together sequentially due to different configurations, and if the primary seal is lost, the secondary circuit is activated, thereby ensuring the reliability of the sealing of the entire device. This ensures the reliability of the device and eliminates the possible leakage of the transported material into the environment.

The configuration of the primary seal circuit differs from that of the secondary seal circuit in the shape of the ring, seat, and ring-to-seat seal. The design of the breakaway sleeve contains a trap for the yoke, which allows you to limit the travel of the yoke when it is opened and thereby protect against shock, damage and engagement of the elements of the emergency release system. The yoke latch contains a shear pin for locking the latch, which ensures its protection from self-opening. The mating surfaces of the clamp and the washer at the point of their connection are made in the form of a hemisphere, which eliminates jamming during separation.

The trunnions are made with the possibility of implementing hydraulic and manual key control.

The design of the breakaway sleeve provides for the possibility of implementing the control of the tightness of the sealing circuits for shutting off the fluid flow. In this case, an output channel with a plug and a pressure sensor located on it is created in the clutch housing.

The seats of the primary and secondary seal circuits are movable and are pressed against the ball under the influence of a spring. Due to this, a possible misalignment of the installation of the ball-seat seals relative to the ball is excluded and tight contact is ensured at the place of their pressing, resulting in a high tightness of the connection.

A shear screw is provided in the design of the coupling, designed to fix the trunnion from possible rotation and closing of the valve when exposed to the pusher.

In the breakaway device, it is possible to implement a nitrogen purge channel for cryogenic applications. The low operating temperature precludes the use of lubrication, so a nitrogen purge system should be used. Nitrogen purge is carried out in order to eliminate condensate, that is, condensate is blown out so that the condensate does not crystallize into ice. Nitrogen purge is carried out before the product is pumped through the stander pipeline, as well as during pumping and after. The trunnion (the pivoting mechanism for turning the ball into the open/closed position) is kept dry and filled with nitrogen.

Brief description of the drawings

The invention is illustrated by drawings, where:

in fig. 1 shows a general view of the breakaway clutch;

in fig. 2 - general view of the breakaway coupling, side view;

in fig. 3 - bursting clutch in the "Open" position;

in fig. 4 - View A. Primary seal circuit;

in fig. 5 - View B. Secondary seal circuit in the "Open" position;

in fig. 6 shows the breakaway clutch in the "Closed" position, where P is the pressure;

in fig. 7 - View B. Secondary seal circuit for the "Closed" position.

in fig. 8 - an enlarged image of the secondary contour of the seals with a bevel on the ring-seat seal;

in fig. 9 - mating clamp and washer.

in fig. 10 is a general view of the breakaway clutch in the version with the second hydraulic cylinder.

Implementation of the invention

Explosive clutch consists of valves 1 and 2, fastened together by a clamp 3 and a latch 4 with a shear pin 5 (Fig. 1, 2). Brackets 6, 7 are installed on the valve bodies. A hydraulic cylinder 8 is installed on the bracket 6, on the rod of which a pusher 9 is fixed. A pusher 10 with a stop of the pusher 11 is installed on the bracket 7, and a shear screw 12 and a thrust screw 13 are fixed. On the reverse side of the pushers 9 , 10 fixed thrust plates 14, 15 (shown by a dashed line in Fig. 2). The pins 16, 17 are mounted on movable supports 18 of the valves 1, 2. A trap 19 is fixed on the valve 2. The supports are fixed in the seats of the main body 20 (Fig. 3).

The device works as follows. The product (for example, liquefied natural gas) is pumped under pressure through the inside diameter of the product. In the event of an emergency, a hydraulic cylinder is activated through a control signal, the hydraulic cylinder rod extends, while the pusher 9 mounted on it rests against the pusher, 10 moves them down. When the pushers move down, the thrust plates 14, 15 simultaneously rotate the pins 16, 17 until they contact the thrust screw 13, while the shear screw 12 is sheared and the through diameter of the product is closed. Further, the stop of the pusher 11 comes into contact with the latch of the clamp 4 and, moving it down, cuts off the shear pin 5 and opens the clamp 3. The trap 19 installed on the valve 2 serves to limit the travel of the clamp 3 when it is opened (Fig. 1).

The clutch in the "Open" position is shown in Fig. 3 and contains a system of seals for shutting off the fluid flow of the valve, a ball 21, the main cavity of the valve 22 and the cavity of the coupling 23. The ball is fixed with the help of movable 18 and fixed 24 supports fixed in the seat of the main body 20.

The fluid shutoff seal system consists of a primary (FIG. 4) and secondary (FIG. 5) seal circuits.

The operation of the breakaway clutch in terms of fluid flow seals (without product) is carried out as follows: a group of springs 25 presses the ring 26 against the ball-seat seal 27, and then, in turn, acting on the seat 28, presses the ring-seat seal 29 to ball 21, thereby closing the circuit (Fig. 4, 5).

In the open position, tightness in the primary circuit of the seals is ensured by pressing and fitting the ball-seat seal 27 located in the seat 28 to the ball 21 due to the transfer of force from the group of springs 25 located in the holes (recesses) of the auxiliary body 30 concentric to the axis of the product flow through the ring 26 and due to the occurrence of force due to the pressure difference on the end faces of the ring 26, due to the clearances between the ring 26 and the seat 28 on the one hand and the ring 26 and the auxiliary body 30 on the other. In this case, the effect of the occurrence of a pressure difference is achieved due to the location of the sealing element ring-seat 29, located linearly between the ring 26 and the seat 28 and diametrically between the auxiliary body 30 and the seat 28 in such a way that the area S ₁ is obviously less than the area S ₂ .

Tightness in the secondary circuit of the seals in the open position of the bursting sleeve is ensured by pressing and fitting the ball-seat seal 27 located in the seat 28 to the ball 21 due to the transfer of force from the group of springs 25 located in the holes (recesses) of the main body 20 concentric to the axis of the product flow through the ring 26, due to the gaps between the seat 28 and the main body 20 on the one hand and the seat 28 and the ball 21 on the other. In this case, the ring-seat seal 29 is located linearly between the ring 26 and the seat 28 and diametrically between the main body 20 and the seat 28, and the shape of the end surfaces of the seat 28 is made in such a way that the area S3 is comparable in size to the area S4, as a result of which the pressing force from product pressure is not generated.

When the breakaway valve is closed, the primary fluid shutoff seal circuit operates similarly to the "Open" position. In the event of a leak (depressurization) in the primary seal circuit, the product penetrates into the cavity of the coupling 23 (Fig. 6), the pressure of the product P through the gaps between the ring 26 and the seat 29 on the one hand, and the ring 26 and the main body 20 - on the other, acts on the end surfaces of the ring 26, while the area S ₆ is made obviously larger than the area S ₅ (Fig. 7).

At the same time, the tightness of the secondary circuit of the seals is ensured by pressing and fitting the ball-seat seal 27 located in the seat 28 to the ball 21 due to the transfer of force from the group of springs 25 located in the holes (recesses) of the main body 20 concentric to the axis of the product flow through the ring 26 and pressing force , formed due to the pressure difference on the end faces of the ring 26 (Fig. 7).

This makes it possible to provide a double circuit (barrier) of sealing protection, when one seal circuit duplicates the function of another.

In the secondary circuit of the seals, it is possible to perform the ring-seat seal 29 adjacent to the ring 26 with a bevel (Fig. 8). In this case, in the open position, the pressure force due to the increase in pressure of the product on the end surface of the ring exceeds the force from the action of the springs on the ring 26, which entails depressurization and the formation of a gap between the seat 28 and the ring with seal 29 and equalizes the pressure in the cavity of the coupling 23. This ensures that the load is removed from the ball 21 and its smoother and less stressful switching to the closed position.

The mating surfaces of the clamp 3 and the washer 31 at the point of their connection are made in the form of a hemisphere, which eliminates jamming during separation (Fig. 9).

In the design of the breakaway clutch, it is possible to use the drive 32 (hydraulic cylinder), which is connected to the plug 33 with the trunnion socket 10 and mounted on the rack 34, which is fixed on the bracket 5 (Fig. 10).

It is also possible to install a position sensor 35 on the bracket 5, which will determine the position of the hydraulic cylinder rod 27.

Thus, thanks to the proposed design solution of the breakaway coupling, sequential operation of the primary and secondary seal circuits in the closed position is ensured, when, in the event of loss of tightness of the primary sealing circuit, the secondary one is activated and reliable sealing of the breakaway coupling is provided in each valve of the breakaway coupling, which makes it possible to disconnect the pipelines without losing the transported substance and prevent its leakage into the environment, thus increasing the reliability of the device. At the same time, with an open passage channel for fluid flow, the secondary seal circuit provides the possibility of depressurization and equalization of pressure between the space of the primary and secondary seal circuits (coupling cavity 23) and the passage channel for fluid flow (valve cavity 22) due to the pressure exceeding the force of the spring group fluid string, as a result of which the load on the ball is removed and there is an easy and smooth rotational movement, which allows to increase the service life of the device.

Claims (7)

1. Explosive clutch with a through channel for a fluid medium, which has two valves connected to each other by a clamp, a mechanical disconnector with a drive, which by means of a pusher ensures closing and disconnection of the valves of the explosive clutch, each valve contains: the main and auxiliary housings located coaxially with an emphasis on the end and the possibility of fastening by means of a threaded connection; a ball with a passage channel for fluid, connected to the main body by means of fixed and movable supports fixed in the seats of the main body, while the movable support through the trunnion mounted on it enters into conjugation with the pusher of the drive and performs rotational movement of the ball to block the passage channel; two sealing circuits - primary and secondary, located in the seats of the main and auxiliary housings and consisting of: a group of springs located eccentrically to the axis of the passage channel; ball-seat seals and ring-seat seals of a different configuration for each circuit, pressed against the surface of the ball by a group of springs; rings and seats, having a different configuration for each sealing circuit and located concentrically to the axis of the passage channel, while, in the event of loss of tightness of the primary sealing circuit in the closed position, the secondary sealing circuit is designed to maintain the tightness of the bursting coupling due to the pressing force arising due to the difference pressure on the end faces of the elements and structurally provided gaps between the elements of the seal contour. 2. Explosive coupling according to claim 1, characterized in that the body of the ball valve contains a trap for the clamp. 3. Explosive coupling according to claim 1, characterized in that the lower end surface of the ring-seat seal adjacent to the ring in the secondary seal is made with a bevel. 4. Explosive clutch according to claim 1, characterized in that the design of the clutch has a shear pin designed to fix the clamp latch from preventing its self-opening. 5. Explosive clutch according to claim 1, characterized in that the device of the explosive clutch has a channel for purging with nitrogen for cryogenic performance. 6. Explosive coupling according to claim 1, characterized in that the mating surfaces of the clamp and the washer at the point of their connection are made in the form of a hemisphere. 7. Explosive clutch according to claim 1, characterized in that the design contains a second actuator with position sensors connected to the plug and to the trunnion socket, which allows you to control the opening / closing of the valve.

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