Apparatus for conducting a hydraulic proof test

Abstract

The invention relates to a hydraulic proof test assembly comprising at least a valve (1) with parallel seats (102). It comprises: a shut-off member (2) with parallel plates (20, 21), connected by connecting means for regulating their separation, to make them go from a first position in which this separation is sufficient to enable the shut-off member (2) to be introduced into said valve (1) to a second position where said separation is greater, this separation making it possible to apply them firmly against said parallel seats (102); a device (3) for inserting said shut-off member (2) into said valve (1) which comprises at least a “U” shaped tool, configured to be introduced into said valve (1), its parallel arms forming guides, while its base forms a support for retaining said shut-off member (2); a “dummy stem” (4).

Claims

1. Assembly for conducting a hydraulic proof test, which is a pressure resistance test, of a hydraulic installation which comprises a valve with parallel seats, a body of this valve having been stripped beforehand of its actuating stem, its parallel gates and a bonnet supporting said actuating stem, thus freeing an opening for accessing said parallel seats, wherein said assembly comprises: a shut off member with parallel plates, one of said parallel plates being apertured and an other of said parallel plates being solid, said parallel plates being connected by connecting means making it possible to regulate their mutual separation, so as to be able to make them go from a first position, which is a retracted position in which this mutual separation is sufficient to enable the introduction of said shut off member into said valve via said opening, to a second position, which is an expanded position, in which said mutual separation is greater than that of said parallel plates in said first position, said mutual separation making it possible to apply said parallel plates firmly against said parallel seats-; a device for inserting and supporting said shut off member inside said valve, wherein said device comprises an inner tool which has a general “U” shape and is configured to be introduced into said valve, parallel arms of said inner tool forming guides for introduction and removal of said shut-off member, while a base of the inner tool forms a support for retaining said shut-off member, allowing a view of the application of its parallel plates against said parallel seats; a dummy stem, which is a sealing equipment configured to close said valve in a leak tight manner after putting said bonnet back in place on said body.

2. Assembly according to claim 1, wherein said parallel plates are capable of being dismantle and interchanged.

3. Assembly according to claim 1, wherein said connecting means connecting said parallel plates of said shut-off member comprise a spring configured to bring said parallel plates into said second position, and a jack controllable on demand, to force said parallel plates to occupy said first position against an action of said spring.

4. Assembly according to claim 1, wherein said connecting means connecting said parallel plates of said shut-off member comprise a spring configured to bring said parallel plates into said first position and a jack controllable on demand, to force said parallel plates to occupy said second position against an action of said spring.

5. Assembly according to claim 1, wherein said dummy stem is a gland or an autoclave.

6. Assembly according to claim 1, wherein said dummy stem is provided with a vent line.

7. Assembly according to claim 1, wherein said dummy stem is provided with instrumentation means.

8. Assembly according to claim 1, wherein said connecting means connecting said parallel plates of said shut-off member comprise a set of connecting rods hinged on a first plate and on a second plate of said parallel plates.

9. Assembly according to claim 8, wherein each connecting rod of said set of connecting rods is hinged on one of said parallel plates via a sliding pivot link.

10. Assembly according to claim 1, wherein said device for inserting and supporting said shut off member also comprises an external tool; configured to be positioned on a seal plane of said bonnet, around said opening and to enable the centering of said inner tool.

11. Assembly according to claim 10, wherein said device for inserting and supporting said shut off member also comprises a pair of external guiding extensions, configured to be positioned on said external tool; in continuation of the parallel arms of said inner tool.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other characteristics and advantages of the invention will become clear from reading the detailed description that follows. It will be made with reference to the appended drawings in which:

(2) FIG. 1 is a schematic view, along a vertical sectional plane, of a known parallel seat valve structure, on which it is proposed to carry out a limit hydraulic proof test (pressure resistance test);

(3) FIG. 2 is a schematic front view of a shut-off member with parallel plates which forms part of the assembly according to the present invention;

(4) FIG. 3 is a view of the shut-off member of the preceding figure, in a first position;

(5) FIG. 4 is a view of the shut-off member of FIG. 2, in another position;

(6) FIG. 5 is a front view of an alternative of the shut-off member with parallel plates illustrated previously;

(7) FIG. 6 is a schematic front view of the shut-off member of FIG. 5;

(8) FIG. 7 is a view of the shut-off member of the preceding figure, in a first position;

(9) FIG. 8 is a view of the shut-off member of FIG. 6, in another position;

(10) FIG. 9 is a first diagram intended to explain how the shut-off member of FIGS. 2 to 4 is put in place inside the valve structure to test;

(11) FIG. 10 is a second diagram intended to explain how the shut-off member of FIGS. 2 to 4 is put in place inside the valve structure to test;

(12) FIG. 11 is a first diagram intended to explain how the shut-off member of FIGS. 5 to 8 is put in place inside the valve structure to test;

(13) FIG. 12 is a second diagram intended to explain how the shut-off member of FIGS. 5 to 8 is put in place inside the valve structure to test;

(14) FIG. 13 is a first view showing, in perspective, a device for inserting and supporting the shut-off member with parallel plates which forms part of the assembly according to the present invention;

(15) FIG. 14 is a second view showing the device of the preceding figure, said shut-off member being in its initial position in FIGS. 3 and 7, before lowering into the valve structure;

(16) FIG. 15 is a third view showing the device of FIG. 13, said shut-off member being in its final position;

(17) FIG. 16 is a schematic view of a first embodiment of a “dummy stem” which forms part of the assembly according to the present invention;

(18) FIG. 17 is a schematic view of a second embodiment of a “dummy stem” which forms part of the assembly according to the present invention;

(19) FIG. 18 is a schematic view showing the valve structure of FIG. 1 during a hydraulic proof test by means of a first alternative of the assembly according to the present invention;

(20) FIG. 19 is a view showing the valve structure of FIG. 1 during a hydraulic proof test by means of a second alternative of the assembly according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(21) An aim of the present invention is to propose a shut off device for valves with parallel seats making it possible to resolve at least one of the drawbacks cited in the introduction of the present application.

(22) In particular, an aim of the present invention is to propose a shut-off device suited to all dimensions and all manufacturers of valves with parallel seats, thus making it possible to respond to the whole range of needs for hydraulic proof tests of equipment and capacities, notably of nuclear power plants.

(23) Before going into the detail of what composes the assembly according to the present invention, reference will be made to appended FIG. 1 in which is represented a known structure of valve 1 with parallel seats, on which it is proposed to carry out a hydraulic proof test (pressure resistance test).

(24) This valve 1 comprises a body 10 surmounted by a bonnet 11, which has an upper opening 111. This bonnet 11 defines an inner space 110. The reference 112 designates the seal plane of the latter.

(25) The body 10 defines an upper space 100 of vertical orientation which is situated exactly in the continuation of the aforesaid space 110. The space 100 communicates through its lower part with a lower space of horizontal orientation 101 which is the place of passage of the fluid through the valve 1.

(26) The reference 102 designates the two parallel seats against which bear, in normal times, the gates of this valve. Finally, the reference 103 designates the distance between the two seats 102.

(27) As has been described previously, the assembly according to the present invention comprises a shut-off member with parallel plates.

(28) A first embodiment thereof is shown in FIGS. 2 to 4.

(29) This shut-off member 2 comprises two parallel plates 20 and 21 of identical shape, one 20 being solid, while the second 21 is apertured. These plates, of general disc shape, have on their outer face (that is to say that which is turned in the direction opposite the other plate) a peripheral seal, not represented. Preferentially, these plates are provided to be dismantlable and interchangeable.

(30) These plates are connected by connecting means making it possible to regulate their mutual separation.

(31) In this case, we are dealing here with at least a helicoidal spring 22 and a jack 23, which are arranged one beside the other, that is to say in parallel.

(32) The two opposite ends of the spring 22 are fixed on the faces facing the plates 20 and 21. The body 230 of the jack is fixed to the plate 20, while the free end of its stem 231 is fixed to the plate 21. Obviously, a reverse mounting may be envisaged.

(33) In this embodiment, it is envisaged that the spring 22 naturally tends to expand, so as to increase the mutual separation between the plates 20 and 21. Under these conditions and as shown in FIG. 3, it is necessary to control the jack 23, so as to command the retraction of its stem 231, against the spring 22 to adjust to the minimum the space between the plates 20 and 21.

(34) The jack 23 is preferentially supplied with air but may also be supplied with water in the event of unavailability of the air network. In FIG. 3, the shut-off member 2 is represented in retracted position, the compressed air being present in the cage of the jack, while in FIG. 4 the shut-off member is in expanded position, and the air inlet is disconnected.

(35) Conversely, in an alternative not illustrated here, the spring may be provided to force the two plates to come close to one another, the jack then being controlled on demand to force the plates to move away from one another.

(36) A second embodiment of the shut-off member 2 is presented in FIGS. 5 to 8.

(37) In these figures, the parts bearing the same references as those of FIGS. 2 to 4 are identical.

(38) The means which make it possible to modulate the separation between the plates 20 and 21 are here exclusively mechanical.

(39) Thus, the solid plate 20 is coupled to a helicoidal screw 24 on which are arranged two sliding pivots 25. Furthermore, on each of these pivots 25 is hinged a connecting rod 26. The opposite ends of these connecting rods are practically contiguous and are hinged for their part on the plate 21.

(40) In these conditions and as shown particularly in FIGS. 7 and 8, by actuating the helicoidal screw 24 in one direction or another, it is going to be possible to adjust the separation between the plates 20 and 21.

(41) Whatever the embodiment that is considered, the shut-off member 2 is going to be able to adopt a “retracted” position in which the separation between the plates 20 and 21 is minimal and is benefitted from to enable its introduction into a valve structure to shut off.

(42) This is what is represented in the appended FIGS. 9 and 11, which show that after having stripped the valve 1 of its bonnet 11, it is possible to introduce therein through the space 100, said shut-off member 2, then to displace it according to a descending movement of vertical orientation, facing the seats 102. It will be arranged so that their dimensioning enables the putting in place in valve bodies of which the inter gate spaces are restricted.

(43) Once in position, the shut-off member 2 may be controlled so that the distance between the plates 20 and 21 increases, until the plates 20 and 21 bear on the seats 102 of the valve 1, until the perfect leak tightness necessary for the hydraulic proof test is obtained (see FIGS. 10 and 12). Once in position, leak tightness is guaranteed without requiring control or adjustment in service.

(44) Obviously, the seals that equip the plates 20 and 21 make it possible to protect the seats 102 of the valve 1, the seal of the solid plate 20 being designed to hug the corresponding seat, thus guaranteeing leak tightness in all circumstances. This seal makes it possible to absorb potential surface inequalities.

(45) As specified above in the present description, the assembly according to the present invention furthermore comprises a device for inserting and supporting said shut-off member 2 inside the valve 1.

(46) Reference will be made more specifically to FIGS. 13 to 15 to describe a possible embodiment of this device 3.

(47) In the embodiment described here, the device 3 comprises an “external tool” 30 intended to bear on the seal plane 112 of the bonnet 11 of the valve 1, while leaving accessible the whole of the access to the space 100. This tool, which can be qualified as platform, has for vocation to be dismantled before closing of the valve (refitting of the bonnet 11) to conduct the hydraulic proof test.

(48) The insertion device 3 also comprises, as indicated above, an “inner tool” 31.

(49) As is clearly visible in the appended figures, this tool 31 has a general “U” shape and is configured to be introduced into the valve 1, the parallel arms 310 of this “U” shaped tool forming guides for the introduction and the removal of the shut-off member 2, while its base 311 forms a support for retaining said shut-off member 2 with a view to the application of its parallel plates 20 and 21 against the parallel seats 102 of the valve. Although it is not visible in the figures, at least one wedge is positioned between the shut-off member and the tool 31 to achieve the centring of the shut-off member.

(50) Obviously, the tool 31 comprises fastening means which make it possible to make it integral with the external tool 30.

(51) Finally, the device 3 comprises a pair of external guiding extensions 32, configured to be positioned on the “external tool” 30, in the continuation of the arms 310 of the “inner tool” 31.

(52) In order to put the shut-off member 2 in place in the valve 1, said shut-off member is positioned between the extensions 32 (see FIG. 14) and progressively lowered down to the base of the inner tool 31, which makes it possible to slide the shut-off member to its final position. Once in place, the shut-off member 2 is expanded to obtain leak tightness. An automatic locking system makes it possible to make the shut-off member 2 and the inner tooling 31 integral. The inner tooling 31 remains in place in the valve during the hydraulic proof test, the external tool 30 and the external extensions 32 being dismantled. It will be extracted jointly with the shut-off member 2 when the hydraulic proof test has finished. It is provided so as not to hinder the conducting of the hydraulic proof test.

(53) Once the shut-off member is in place, it is necessary to reposition the bonnet 11 of the valve 1, and to provide a “dummy stem” to replace the original stem of the valve 1, so as to ensure leak tightness at the level of the bonnet and, if necessary, the venting of the circuit.

(54) Thus, the assembly of the invention comprises such a “dummy stem” of which two alternative embodiments are represented schematically in FIGS. 16 and 17.

(55) This dummy stem is preferentially suited to all parallel seat valve technologies and thus adapts to the dimensions of the different bonnets and to the range of test pressures. A venting function is provided which may if necessary be blocked for maintenance type requirements not requiring this functionality. A pressure, temperature or other measurement type instrumentation may also be envisaged via this dummy stem.

(56) In the embodiment presented in FIG. 16, it is a dummy stem 4 of gland type.

(57) It is composed: of a hollow stem 40 forming a vent line and making it possible to fulfil the venting function of the tooling; of steel washers and rubber seals (preferably EPDM (ethylene-propylene-diene monomer)) 42 which are compressed to enable the sealing of the dummy stem during the hydraulic proof test, of a follower 41 and supporting washers 43 to enable the maintaining in position of the aforesaid washers and seals.

(58) In the embodiment shown in FIG. 17, it is a dummy stem 4 of autoclave type.

(59) This dummy stem is composed of: a venting valve placed on a hollow and threaded stem 44; a clamping washer 45; a sealing cone 46, for example made of Teflon (registered trademark) operating by autoclave effect.

(60) The cone is put in place with a slight tightening guaranteeing leak tightness during filling at atmospheric pressure, the increase in pressure in the body of the valve making it possible to apply a greater force on the cone and thus guaranteeing leak tightness at the test pressure.

(61) The shut-off device 2 and its dummy stem 4 are dimensioned for a very wide test pressure range (up to 250 bars), making it possible at least to cover the needs of the equipment and capacities of French nuclear power plants.

(62) Reference will be made to FIGS. 18 and 19 to visualise the emplacements of the shut-off member 2 and the dummy stem 4 during the hydraulic proof test.

(63) This assembly has been designed for hydraulic proof tests of exchangers and capacities of the conventional island of nuclear power plants. However, it may be used on all valves with parallel seats needing to be shut off, whether it is for maintenance operations or tests, trials or hydraulic proof tests in any type of industry (chemicals, petrochemicals, gas, etc.).

(64) In the particular case of hydraulic proof tests of exchangers and capacities of French nuclear power plants, the following advantages are highlighted: The putting in place of the tooling is simple, it does not require particular skills other than the basic skills required within the context of hydraulic proof tests. It does not require either undergoing specific training, an operating manual being provided for the intervention; An intervener can put in place the tooling alone in complete safety, which makes it possible to optimise the resources mobilised on the activity. For valves of large dimensions, the insertion device enables the putting in place of the tooling with the same advantages whatever the configuration of the valve (vertical or inclined); The dummy stem makes it possible to expel the air trapped in the pipe which guarantees pressure stability in the bubble; The use of this tooling brings economic savings with respect to the solutions currently implemented which are internal interventions of valves or the putting in place of welded shut-off devices. The use of this tooling also makes it possible to reduce the planning of the activity with respect to the carrying out of welding works, the return to compliance of the equipment being faster. Its use does not require any energy source, of any type, during pressure resistance tests, making its exploitation autonomous.