GB2263157A

GB2263157A - Underwater pipeline valve

Info

Publication number: GB2263157A
Application number: GB9300101A
Authority: GB
Inventors: Per Jan Langerud
Original assignee: Kvaerner Energy AS
Current assignee: Kvaerner Energy AS
Priority date: 1992-01-07
Filing date: 1993-01-05
Publication date: 1993-07-14
Anticipated expiration: 2013-01-05
Also published as: GB9300101D0; NO920086L; GB2263157B; NO920086D0; NO174066B; NO174066C

Abstract

An underwater pipeline valve is designed with a valve housing (1) having an inlet and outlet (2, 3) and a passageway (4) in communication therewith. A chamber (5) intersects the passageway (4) in the valve housing (1) and receives an insert (6) having a blocking member (7) for the passageway. The insert (6) is releasably coupled to a shut-off-body (9) having a through passage (10). The shut-off body (9) is received in the chamber (5) and, on removal of the insert (6) from the chamber will move into an active position in which the shut-off body connects the inlet and outlet (2, 3) via the through passage 10 while preventing leakage from the valve housing thus allowing removal of the insert without shutting down the pipeline to which the valve is fitted. The valve permits pigging and also valve maintenance under full operational pressure. <IMAGE>

Description

Shuttle valve The invention relates to a shuttle valve comprising a valve housing having an inlet and an outlet and a passageway in communication therewith, a receptacle intersecting the passageway in the valve housing for an insert having a blocking body for the passageway, and a blocking body actuator for movement of the blocking body between an open and closed position with respect to the passageway.

The invention was developed specifically to meet the need for a shuttle valve in underwater conduits designed for conduction of fluid streams in connection with offshore facilities for the production of oil and gas. Primarily this relates to gas lines on the sea floor, where the intention is to prevent the uncontrollable flow of the gas in the gas line back to a platform or similar facility in the case of fire. Under such conditions, a valve located "top side" would quickly be ruined.

Special requirements are set for such valves. The valve should have a long lifetime, for example 30 years, and should be capable of tolerating substantial pressure, for example 180 bar. A typical area of utilization for the valve is at an ocean depth of down to 400 meters. During ordinary operation when the valve is open, it is a requirement that the gas line be capable of being pigged. It is also an important requirement that the valve be capable of undergoing maintenance under full operational pressure, i.e., that all parts with the exception of the valve housing may be brought up to the surface for maintenance without its being necessary at any time to interrupt the delivery of gas.

It should be evident from these and other requirements set for the shuttle valve that the valve should have as many passive components as possible in the parts that are not changeable. The active components in the non-replaceable parts should be as robust as possible. These requirements also pertain, of course, to the components and parts that may be brought up and changed, since the primary objective is to have a valve that is as safe and maintenance-free as possible.

As stated above, it is important that the valve may be serviced while under full operational pressure without interrupting the gas delivery, and according to the invention we therefore propose a shuttle valve as defined above, characterized in that the insert is attached to and releasably coupled with a shut-off body having a through-going passage, which shut-off body is fitted to the receptacle and on removal of the insert from the receptacle will move into an active position in which it will close off the receptacle's opening to the valve housing passageway freed by removal of the insert, at the same time as the through-going passage is brought into alignment with the passageway in the valve housing.

With this embodiment of shuttle valve, one is able to maintain the fluid flow through the valve even when the insert with the blocking body is removed, because the valve housing will be closed to the exterior by the shut-off body; i.e., the receptacle is closed, at the same time as the fluid may flow within the pipeline, through the through-going passage in the shut-off body. After maintenance is completed, the insert with its appurtenant parts is lowered down again and put in place in the receptacle, while beneath it the shut-off body will be actuated by and coupled with the insert and brought into a passive position.

A particularly advantageous embodiment of the new shuttle valve is one where the blocking body is a valve gate, or valve disc, and where the shut-off body is formed with a well for receival of the valve gate.

A shuttle valve of this type will have a very favorable mode of operation/working principle, with movements as linear as possible, without any form of directional change. The configuration of the well for receival of the valve gate in the shut-off body contributes toward reducing the structural height of the shuttle valve.

A preferred embodiment of the shuttle valve is characterized by an actuator housing attached to the receptacle, in which housing the insert is slidably received, said insert being connected with an actuator in the actuator housing, for movement in and out of the receptacle. The insert may then be moved in and out of the receptacle in an externally closed chamber in an advantageous, protected manner.

A particularly appropriate actuator for the blocking body in this connection is an actuating cylinder connected to the insert and received in the actuator housing.

A preferred embodiment is further characterized in that the insert actuator is an actuator cylinder having a cylinder and piston, and that the piston for the blocking body actuator is provided with an indicator rod that passes out of the actuator housing through the insert actuator's piston and a rod sleeve connected thereto, which also passes out of the actuator housing. By this means a mechanical indication is provided on the exterior, showing the condition of the valve or the position of the blocking body, which affords security in the case of pigging by providing an external indication showing that the valve is open and that pigging may thus be carried out.

To facilitate the placement and attachment of the actuator housing, the valve housing may advantageously be provided with a plurality of guide posts distributed around the actuator housing, the actuator housing having guide funnels cooperative with the guide posts and having lock ring halves cooperative with the guide posts, which lock rings when joined together around the respective guide post have an exterior conical shape and could be secured by a securing ring having an internal cone configuration which is fitted over the corresponding external cone formed by the joined lock ring halves.

The shuttle valve, i.e., the serviceable parts thereof, may be put in place and brought up to the surface with the aid of guiding wires connected to the guide posts on the valve housing. As indicated above, the guide posts will function as cleave bolts and hold the entire valve together. The mentioned locking device in the form of the lockable lock ring halves may be coupled in with the aid of an ROV (Remote Operated Vehicle), i.e., a mini-submarine, after the valve part that had been taken up is resited on the valve housing.

After the valve mechanism is attached to the valve housing and locked on the guide posts, the insert and its appurtenant blocking body are moved into the fluid stream in the pipeline. The valve gate/valve case (insert) and the valve case/valve housing are advantageously designed with a minimal clearance (suction fit) in order to prevent impurities from penetrating into the valve mechanism during pigging and normal operation. During assembly and disassembly of the valve mechanism, pressure conditions must be taken into consideration, and the shuttle valve is therefore equipped with suitable internal valve devices.

Hence, the shut-off body advantageously has a valve device located between the through-going passage and the outsidefacing toward the insert, said valve device being such that it is actuated to open when the insert is moved against and coupled with the shut-off body. This valve device will ensure equilibrium when:the valve mechanism is put in place in the valve housing because said valve devicewill belforce- opened when actuated by the insert. The gas pressure in the line/valve housing will then be released into the actuator housing, enabling attainment of the same gas pressure over the entire system, and affording relief for all the seals when the valve mechanism and shut-off body are pushed down into the valve housing.

It is particularly advantageous for the valve housing to have a valve device situated between the valve housing passageway and the part of the receptacle where the shut-off body enters when the insert is placed in the receptacle. This valve device is caused to move into open position by the shut-off body when said shut-off body is in active position and closes when the shut-off body leaves its active position. Furthermore, it is advantageous to have a one-way valve in the shutoff body, located between the part of the receptacle where the shut-off body enters when the insert is placed in the receptacle and the through-going passage in the shut-off body. When the shut-off body moves out of its active position, said valve device will be closed to the gas flow, thus protecting the valve device against contamination, of the type that occurs particularly in pigging.The one-way valve provides for drainage of gas and any possible condensate into the pipeline. Said one-way valve is adjusted so that it does not open prior to the attainment of a pressure of, e.g., water pressure plus 10 bar. Water will then be prevented from penetrating into the pipeline when the gas pressure falls below the surrounding water pressure.

All of the aforementioned features are of inventive significance, both in combination and independently. Additional important features also having inventive significance will be further elucidated below in the following description of a preferred emnbodiment of a new shuttle valve in accordance with the invention, given by way of example and as shown in the drawings, in which:: Fig.1 is a longitudinal section through a shuttle valve according to the invention, Fig.2 is a cross-section taken on line H-H in Fig.l, Fig.3 is a longitudinal sectional view through the valve, taken on line F-F in Fig.2, Figs. 4, 5 and 6 are, respectively, an enlargement of the part in circles D (Fig. 3),C (Fig.3) and B (Fig.l), Fig. 7 is a section taken on line G-G in Fig. 1, Fig. 8 is an enlargement of the part in circle K (Fig. 3), Fig. 9 is an enlargement of the part of Fig. 3 shown by the arrow A, Fig. 10 is a cross-section similar to Fig. 2, Fig. 11 is an enlargement of the section on the line L-L in Fig. 10, and Fig. 12 is a longitudinal section of the valve housing with a blind cover installed thereon.

The shuttle valve shown in the drawings comprises a valve housing 1 having an inlet 2 and an outlet 3 and having a passageway 4 joining the inlet and outlet. The valve housing further comprises a receptacle 5 intersecting passageway 4 and receiving an insert 6. This insert 6 forms a valve case for a valve disc or valve gate 7.

Receptacle 5 intersects passageway 4, as mentioned, and is closed on the bottom side of valve housing 1 by a shut-off housing 8. Housing 8 has, as shown, the shape of a cup and is flanged to valve housing 1. Space is provided in housing 8 for a shut-off body 9, as shown in Fig. 1. This shut-off body 9 is formed with a through-going passage 10. Shut-off body 9 has a lower encircling collar 11 which is slide fitted into the cup-shaped shut-off housing 8, and has- an :upper section 12 in the shape of a disc, having an encircling-edge that is slide fitted into receptacle 5.When shut-off body 9 assumes the active position shown in Fig. 3, section 12 will close off the opening where receptacle 5 runs into valve housing passageway 4 at the top thereof, so that the valve housing is sealed off externallg while at the same time permitting open flow, through the through-going passage 10 in shut-off body 9. In both collar 11 and the disc-shaped upper section 12 there are inserted, as indicated, suitable packings for sealing against, respectively, the inner wall in the cup-shaped housing 8 and the inner wall of receptacle 5.

Shut-off body 9 is formed with a well 13 for receival of the valve gate 7. Thus, from the open position shown in Fig. 1 with respect to passageway 4, valve gate 7 may be moved to a closing position with respect to passageway 4, in which closing position the valve gate will project down into well 13 in shut-off body 9, as indicated with dotted lines.

It is also possible to construct the valve gate in such a manner as to permit attainment of the closing function when the gate is in the upper position.

The valve gate may be moved up and down as indicated by the double arrow in Fig. 1 by means of an actuating cylinder, the cylinder 14 of which is mounted on valve case 6 and the piston 15 of which is connected by means of a piston rod to valve gate 7.

Actuating cylinder 14-16, which constitutes the actuator for the valve gate, is disposed in an actuator housing 17 situated on valve housing 1. Actuator housing 17 is provided at the upper part thereof with a cylinder 19 provided with an end flange 18, in which cylinder is disposed a piston 20.

Piston 20 is connected with cylinder 14 in the valve gate actuator. Cylinder 19 and piston 20 constitute an actuator for insert 6, which is connected with cylinder 14, as mentioned above.

From piston 20 a rod sleeve 21 runs up and out through a top plate 22 screwed onto cylinder 19. Flange 18 on cylinder 19 is, as indicated, attached to the top of the shell wall in actuator housing 17. From piston 15 in the valve gate actuator, a rod 23 passes up through rod sleeve 21 and out, and into a sleeve 24 mounted on the top of actuator housing 17. Sleeve 24 has a plurality of openings permitting one to observe, from the outside, the position of rod 23 in the longitudinal direction, i.e., to observe an appropriate marking point which will indicate the position of piston 15 and thereby also the position of valve gate 7, i.e., indicating whether the valve gate is in open or closed position.

Insert 6 and shut-off body 9 may be coupled together by means of a simple connection device 27, see Figs. 10 and 11.

Two bolts 28 project upwards from shut-off body 9, 12. The insert -- here being valve case 6 -- is provided with two radial blind bores 29 intersected by a respective axial blind bore 30, designed for receival of a respective bolt 28. In the radial blind bores 29 are positioned a respective locking bolt 31. This locking bolt is actuated by a spring 32, causing the locking bolt to enter a locking recess 33 in valve housing 1 when the valve case and the shut-off body coupled thereto are brought into the position shown in Fig.

3. Bolt 28, the movement of which is blocked by means of lock piece 34, the latter being brought into blocking position relative to bolt 28 with the aid of a spring 35, will then slide out of engagement with lock piece 34, and shut-off body 9 will then be disengaged from the valve-case or insert 6. Radial locking bolt 31 has, as shown,= an: elongated bore 36 therethrough . to receive bolt 28 and to: permit the radial displacement in and out of locking recess 33.

On valve housing 1 are formed cylindrical sockets 37 for guide posts 38. These guide posts 38 are connected with respective guiding wires 39 which run to the surface (here it is assumed that the shuttle valve is installed in a pipeline on the sea floor). Actuator housing 17 is provided with similar guide funnels/sleeves 40 cooperative with the guide posts and has, in addition, lock ring halves 41,42 also cooperative with the guide posts (Fig. 9). These lock ring halves 41,42 are pivotably mounted 43,44 in a suitable manner on actuator housing 17 and are thus manipulatable between the open positions indicated with broken lines and the positions indicated by the solid lines, where the lock ring halves grip around the respective guide posts 38.The lock ring halves have a conical exterior shape when joined together around the guide post, and may as shown be secured by a securing ring 45 having an internal cone configuration (Fig. 3). The lock ring halves will secure the actuator housing, as shown, by gripping around the respective guide posts, and engage with locking grooves 46 on the guide posts.

The shuttle valve has internal valve devices which will be described in more detail below in connection with a discussion of the mounting, function, and dismounting of the valve.

The following is based on a situation in which the valve housing 1 is mounted in a pipeline. The valve housing is provided with shut-off housing 8 having shut-off body 9 in active position. The valve mechanism, i.e., the actuator housing 17 and associated components, will then be mounted in place. This is done by utilizing guiding wires 39, which as mentioned above run from the guide posts 38 on the valve housing and up to the surface.

The valve mechanism is lowered down and guided into place as a function of the cooperation between guide funnels 40 and guide posts 38. A case guiding 47 in the actuator housing will prevent rotation of the insert (valve case) and associated components (Fig. 1). The valve case and actuator housing are provided with minimal reciprocal clearance (suction fit) in order to prevent impurities from penetrating the valve during pigging and normal operation.

The valve mechanism is mounted and secured with the aid of lock ring halves 41,42, in the state shown in Fig. 3. The valve case and shut-off body are then moved further down through the valve housing with the aid of insert actuator 19,20; in other words, piston 20, situated at its upper position in cylinder 19, is now driven down. Supply lines for hydraulic fluid by which this is made possible are shown and designated by numerals 48, 49 in Fig. 1. Valve C (Figs.

3 and 5) is open, because the valve case bears against the shut-off body and thus presses against valve body 50, as indicated by the arrow in Fig. 5, so that the valve body will assume the open position indicated by the dotted lines.

Valve body 50 is urged toward closed position with the aid of valve spring 51. When valve C is open, the gas pressure in the line/valve housing is released into the actuator housing; i.e., the same gas pressure is attained throughout the valve and all seals will be relieved when the valve case and shut-off body are pushed further down in the valve. A one-way valve 52 provides communication between the chamber in shut-off housing 8 and the upper side of shut-off body 9.

Shut-off body 9 is provided on the lower collar 11 thereof with suitable packings that seal against the inner wall of the cup-shaped shut-off housing 8. Directly above collar 11 the shut-off body 9 is provided with packings engaging with the inner wall of receptacle 5 when the shut-off body is in active position (Fig. 3). The shut-off body has a special sealing arrangement in its top section 12, shown in more detail in Fig. 8 and designated as K (Figs. 3 and 8). The special packing arrangement comprises various types of lip seals 53, 54 as well as special metal scrape rings 55. The packing arrangement is symmetrical, as is apparent from the figures, thus functioning equally effectively in both directions of movement for the shut-off body.

When the shut-off body moves down and toward the position shown in Fig. 1, valve B will be closed against the gas stream because the blocking body 56 in the valve device is no longer urged into open position by collar 11 of the shut-off body. Valve body 56 is actuated for closing by a built-in valve spring 57. The valve device, with check valve 58 attached thereto, will thus be protected against contamination. The head 59 of valve body 56 is in precise alignment with passageway 4, enabling pigging to proceed unhindered.

When the shut-off body is pushed down, the volume on the underside thereof will be closed in since valve B and valve 52 are one-way valves. The only way to drain the underside of the shut-off body will thus be through valve B (Figs. 3 and 4), which will allow the release therethrough of gas and any existing condensate.

Valve D is a one-way valve, as shown in the sectional drawing in Fig. 4, and has the special feature that its dimensions must be such that it is prevented from opening until a certain pressure above the surrounding water pressure has been reached. For example, valve D may be adjusted so that it does not open before the attainment of a pressure of, for example, water pressure plus 10 bar. Water is thereby prevented from penetrating into the valve and pipeline when the gas pressure in the pipeline falls below the water pressure. Any water that might be trapped below the shutoff body must then, of necessity, be pressed into the passage and into the pipeline when the valve mechanism is to be driven into the gas stream again.

When the relevant valve components are brought up for servicing, the opposite sequence is in effect. Piston 20 is driven back, i.e., upwards in Fig. 1, and draws with it the valve case and the shut-off body. When sealing arrngement K in the shut-off body assumes the uppermost sealing position, valve B will be opened (armed), because collar 11 comes into contact with valve body 56, and the gas pressure is permitted to fall below shut-off body 9. Any existing overpressure occurring in actuator housing 17 when the shut-off body continues up in the upper sealing position will be released through check valve 52 and under the shut-off body.When valve case 6 comes into upper position, the connection device 27 between shut-off body 9 and valve case 6 is disengaged, because radial locking bolts 31 will move into their respective locking grooves 33, whereby bolts 28 are disengaged, as described above in connection with Fig. 11.

Before the actuator housing may be disengaged from the guide posts the gas pressure must be released from the actuator housing and the water pressure let in. This can be done with the aid of a remote controlled valve and/or with a manually operated valve 60 on actuator housing 17. By manual operation we mean, in this case, diver operation where conditions permit, or handling by means of an ROV (Remote Operated Vehicle).

When the water pressure is being exerted against the top side of the shut-off body and the gas pressure against the under side, valve 52 will balance the water and gas pressure against each other. Even if the gas pressure in the pipeline should drop rapidly, the gas volume below the shut-off body will be closed in and will not fall below the value set for valve D. Not until a possible leakage in the packings or valve occurs will the pressure in this chamber fall below the water pressure. If the gas pressure should fall below. the water pressure during maintenance work, the water will penetrate through valve 52 and down-under the. shut-off body.

Due to the fact that the shut-offrbody:has a larger diameter at the bottom (collar 11), t will function as. a differential piston, and closure force will be attained even if the gas pressure should, contrary to expectation, drop toward zero during the maintenance phase.

Opening and closing of the shuttle valve is accomplished with the aid of valve gate 7, which is moved up and down with piston 15. Piston 15 goes in cylinder 14 and is actuated by hydraulic pressure medium through the indicated lines 61, 62 in Fig. 1. The valve gate is open during normal operation and when the valve mechanism is moved in/out of the gas stream. The valve gate actuator, i.e., piston 15, is then situated in the indicated upper or rear position. The correct position of the valve gate and valve case is shown, as mentioned above, by a mechanical indication externally at the top of the valve (rod 23).

(esM ) The valve gate advantageously glides against a teflongbased slide coating attached internally to the valve case on the four faces forming guiding/sealing surfaces for the valve gate.

As mentioned above, in order to conserve on structural height the shut-off body is equipped with a well 13 affording clearance when the valve gate is in the lower position. This clearance also makes it possible for the valve mechanism to be brought up to the surface even when the valve gate is in the lower position, as a result of wedging or when the actuator cylinder is not functioning.

It is a distinctive feature of the new shuttle valve that the various components in the valve are pushed back and forth in linear movements during the various operations, without any form of directional change.

Emphasis is placed on the fact that all main components are to be disposed vertically in order to prevent disalignment stresses on the packings and sliding surfaces, i.e., that all parts "float" on the packings.

The major advantage of this solution is that coupling and uncoupling also take place vertically via guiding wires down to the guide posts.

The necessary energy is stored on the valve's actuator housing as accumulator charges (not shown). Valves and the pump aggregates that will monitor and replenish the accumulator pressure are also placed here. The pump aggregates may also be placed on the platform, together with instruments and operational devices. These are then provided with cable connection out to the valve.

In test runs or during emergency shut down, the hydraulic valves on the actuator housing are controlled from the platform. The control signals may be activated manually or automatically.

After the valve mechanism/actuator housing has been brought up to the surface, a blind cover 65 may be lowered down via the guiding wires and locked on the guide posts 38, in the same manner as the valve, as shown in Fig. 12. In addition to a manual and remote controlled bleeder valve 60', the blind cover is also provided with a check valve 66 intended to ensure that there is water pressure on the top side of shut-off body 9. If there should occur a minor gas leakage through the upper seal in the shut-off body, the pressure below the blind cover will rise and the check valve will close, thus preventing gas leakage out into the sea.

The bleeder valves in the blind cover and actuator housing should have a large enough capacity to ensure that a possible.

leakage through the upper packing will not prevent-pressure- release and, with it, the disengagement of the guide posts during coupling and uncoupling of the valve and blind cover

Claims

CLAIMS 1. A shuttle valve comprising a valve housing having an inlet and outlet and a passageway in communication therewith, a receptacle intersecting the passageway in the valve housing for an insert having a blocking body for the passageway, and a blocking body actuator for movement of the blocking body between an open and closed position with respect to the passageway, wherein the insert is attached to and releasably coupled with a shut-off body having a through-going passage, which shut-off body is fitted to the receptacle and on removal of the insert from the receptacle will move into an active position in which it will close off the receptacle's opening to the valve housing passageway freed by removal of the insert, at the same time as the through-going passage is brought into alignment with the passageway in the valve housing.
2. A shuttle valve according to claim 1, wherein the blocking body is a valve gate, and the shut-off body is formed with a well for receival of the valve gate.
3. A shuttle valve according to claim 1 or 2, wherein an actuator housing is attached to the receptacle in which actuator housing the insert is slidably received, said insert being connected with an actuator in the actuator housing, for movement in and out of the receptacle.
4. A shuttle valve according to claim 3, wherein the blocking body actuator is an actuating cylinder connected to the insert and received in the actuator housing.
5. A shuttle valve according to claims 3 and 4, wherein the insert actuator is an actuating cylinder having a cylinder and piston, and on the piston of the blocking body actuator is provided an indicator rod that passes out of the actuator housing through the insert actuator's piston and a rod sleeve connected thereto which also passes out of the actuator housing.
6. A shuttle valve according to any one of the preceding claims 3 to 5, wherein the valve housing is provided with a plurality of guide posts distributed around the actuator housing, and the actuator housing has guide funnels cooperable with the guide posts and lock ring halves cooperable with the guide posts, which lock ring halves when joined together around the respective guide post have a conical exterior shape and are secured by a securing ring having an internal cone configuration which is fitted over the corresponding external cone formed by the joined lock ring halves.
7. A shuttle valve according to any one of the preceding claims, wherein a valve device is provided in the shut-off body, between the through-going passage and the outside of the shut-off body facing the insert, which valve device is adapted to open when the insert is moved against and coupled to the shut-off body.
8. A shuttle valve according to any one of the preceding claims, wherein a further valve device is provided in the valve housing, situated between the valve housing passageway and the part of the receptacle where the shut-off body enters when the insert is placed in the receptacle, which further valve device is caused to move into open position by the shut-off body when said shut-off body is in active position and closes when the shut-off body leaves its active position, and a one-way valve is provided in the shut-off body, between the part of the receptacle where the shut-off body enters when the insert is placed in the receptacle and the through-going passage in the shut-off body.
9. A shuttle valve according to any one of the preceding claims, wherein a blind cover is provided for instalment on the valve housing when the insert is removed.
10. A shuttle valve for underwater applications substantially as herein described with reference to, or as illustrated in, the accompanying drawings.