FR2536824A1 - Device of the magnetically-controlled valve type comprising a remote controlled valve element. - Google Patents

Abstract

The present invention concerns a valve capable of being used especially in the field of radioactive-fluid circuits for nuclear power stations. The valve comprises a body 10 and a cap 20 which houses a shut-off 30 and members 70, 60 for controlling the movement of the latter. The shut-off is composed of a remote controlled valve element 30 associated with a sheath 90 sliding on the stem 60. A calibrated restriction 34 is provided between the valve element 30 and the sheath 90, whilst the valve element 30 is equipped with a T-shaped slot 35 which opens into a chamber of the sheath 95, in the calibrated restriction 34 and in an axial bore 36 of the valve element 30 capable of being shut off by the spherical end 64 of the stem 60.

Description

 The present invention relates to an apparatus or valve, capable of fulfilling the functions of sectioning and sealing on fluid circuits, in particular radioactive fluids used in the context of nuclear power plants.

 More specifically, the present invention relates to a tap of the type comprising a body into which open two conduits capable of communicating with each other, as well as a cap made of non-magnetic material tightly fixed on the body to define a chamber which houses a shutter intended to interrupt the communication between said conduits, as well as shutter movement control members which comprise at least one permanent magnet capable of being moved in rotation by means of an external part adapted to generate a magnetic field of rotary appearance.

 Such devices are described in particular in the patents of the United States of America as No. 2,289,574, No. 3,347,262 (GIBSON), No. 3,355,140 (ANDERSEN) pO 3,908,959 (FICHTNER), and No. 4,232 695 (THE GARRETT CORPORATION), as well as in French patents and patent applications No. 1,200,372 (COTTON DE BENNETOT), No. 2,373,729 (AUTOCLAVE-ENGINNERS) and No. 2,456,892 (AUTOCLAVE ENGINNERS), to which reference will be made for a good understanding of the present invention.

 All these valves must meet an imperative condition, which is that of watertightness to the outside.

 It is understood in particular that this imperative must be respected, in the context of nuclear power plants, when handling radioactive fluids.

On the other hand, said fluids are brought to very high pressures, which can exceed 20 M Pa (200 bars), and to temperatures v; irianl. between pr cxen.ple, 20 to 340 c
In practice, it has been found that
all the taps previously proposed, do not
can give full satisfaction in this sense
that when the fluid pressures exceed a given threshold, the torques applied to the organs
shutter control, thanks to the coupling ma
genetics made between permanent magnets
internal and the external part are insufficient
to move the shutter and carry the tap
in the open position.

In particular, as described
in patent application No. 2,456,892, and such
that this is shown in particular in its figures and 3, it has proved to be essential, with the
previously proposed devices, to provide a mechanical part connected to the shutter control members, and accessible outside the
tap after going through the body wall.

By mechanical intervention on this part, we
can easily control the movement of the obtu
rator. This said part therefore makes it possible to compensate for the faults of the drive system comprising
at least one permanent magnet. The seal between
the part and the body, is realized thanks to
O-rings. However, we can easily understand
that such a provision cannot in any way
produce a perfectly reliable seal.
other words, such a provision, that it
proved essential to use so far, when
the fluids to be handled reach pressures
very high, eliminates all the benefits of
permanent magnet control which allowed
to obtain a perfect seal vis-à-vis the outside and therefore pserite the drawbacks of conventional taps or valves, such as those described in US Pat. Nos. 969803 and 3,269-698. '
It has also been proposed to equip the shutters with bellows, in order to solve the sealing problems, as described in particular in the patents of the United States of America No. 2,642,890 (SKEWIS), No. 4,166,607 (WEBB ) and 4,232,695 (THE
GARRETT CORPORATION) .However, such valves do not have a satisfactory reliability and cannot therefore be used with fluids for which permanent sealing is a primary imperative.

 There is therefore a need on the market to have taps of the aforementioned type, which are at the same time simple, robust, reliable and economical, which can be used with fluids, such as radioactive fluids, reaching very high pressures. high of the order of 20 M Pa, and temperatures of the order of 3500, while presenting a perfect seal vis-a-vis from the outside, and this requiring quite limited maneuvering effort. Preferably, such taps should furthermore require reduced maintenance, and, as far as possible, present a certain safety, allowing the tap to be fitted only by a few given individuals.

 The present invention comes on this point to provide a solution to the problem previously posed, and proposes a new tap of the aforementioned type in which the shutter movement control members also include a screw / nut system, one of the elements of which is integral with the permanent magnet driven in rotation, to transform the rotational movement of the permanent magnet in translation, and in which more precisely the shutter comprises a piloted valve, a chamber provided opposite the seat relative to the valve , and which communicates, via a calibrated restriction, with a first conduit, and by means of a light with the second conduit, this light being capable of being closed by a rod movable in translation of the system screw / nut, when the rod applies the valve against the seat and in which the rod is adapted to move the valve away from the seat, after releasing the light, when the rod is urged away from it headquarters.

 As will appear on reading the detailed description which follows, the present invention makes it possible to obtain perfectly tight taps while requiring reduced operating torques.

 According to a preferred embodiment, the chamber 'provided behind the valve is delimited by a sheath carried sliding on the rod and which houses the flared head, opposite the seat, of the valve, said light opening in said chamber of the sleeve and in a axial through bore provided in the valve, this bore being capable of being closed by the end of the rod, the latter carrying an annular stop housed in the chamber of the sleeve and capable of coming to abut against the bottom thereof when the rod is stressed away from the seat.

 Preferably, the end of the rod capable of closing the through bore of the valve is of generally spherical shape.

 According to a particular embodiment of the present invention, an elastic member of the spring type is introduced into the chamber of the sleeve, between the annular abutment of the rod and the head of the valve.

 According to a characteristic of the present invention, said permanent magnet is connected to an element of the nut type while the screw of the screw / nut system consists of said rod which is immobilized in rotation.

 According to an important characteristic of the present invention, the screw / nut system is carried in the cap by means of elastic washers which allow axial compensation for differential expansions.

 Preferably, the permanent magnets are cobalt and rare earth metal magnets.

 According to an advantageous embodiment, the cap is assembled on the body by bolts and the seal between the cap and the body is ensured by welding lip-seals.

 According to another characteristic of the present invention, said external part adapted to generate a magnetic field of rotary appearance consists of a set of permanent magnets, preferably removable, mounted on the cap and capable of rotation around the axis of the screw / nut system.

 According to a preferred embodiment, said external part capable of rotating the permanent magnets housed in the cap is provided with a torque limiter.

 Other characteristics and advantages of the present invention will appear on reading the detailed description which follows, and with reference to the appended drawing, given by way of nonlimiting example, in which the single figure represents an axial section view of a device according to the present invention.

 It is clear from an examination of the said appended figure, that numerous geometric shapes of the parts making up a valve in accordance with the present invention must be strictly observed so as to allow correct cooperation of these said parts. For these reasons, it will be considered, below, that said appended figure is integrated into the present description, by the reference made to it here, so that this figure clearly defines the geometric shape, and the arrangement of the pieces of a tap according to an embodiment of the present invention.

 In the figure, reference O-O is the longitudinal axis of the valve through which the cutting plane passes, and which corresponds to the direction of movement of the shutter.

As shown in the single appended figure, the valve according to the present invention comprises a body 10 into which two conduits 11, 12 capable of communicating with each other open, and a cap
20, made of non-magnetic material, and tightly fixed on the body 10, to define a chamber 21 which houses a shutter 30 intended to interrupt the communication between said conduits 11 and 12, as well as displacement members of the shutter.

 More specifically, as shown in the figure, the body 10 delimits a valve or valve seat 13, of generally circular shape, equipped with the casing of a body seat ring (not shown in the figure).

The median plane of the seat 13 is substantially perpendicular to the above-mentioned axis O-O which corresponds to the direction of movement of the shutter 30.

More precisely, one of the conduits 11, of generally circular cross section, flows into a blind bore 14 coaxial with the axis
OO cited above, and which opens at the lower part of the seat 13. The duct 11, as shown in the figure is itself slightly inclined relative to the median plane (referenced AA in the figure liu seat 13.

 Similarly, the second conduit 12, of circular cross section, itself inclined with respect to the above-mentioned plane AA, opens into a generally cylindrical chamber 15, axis OO, formed at the upper part of the seat 13, opposite to the aforementioned bore 14.

 More specifically, as shown, the two cylindrical conduits 11 and 12, of respective axes 16 and 17, are substantially parallel.

 At their end opening onto the outside of the body 10, the conduits 11 and 12 are provided with any suitable conventional means capable of allowing their connection to the fluid circuit of an installation.

 In the figure, such connection means have been schematically represented and referenced respectively in 18 and 19.

 As shown in the figure, the cap 20 consists of a first part 22 of generally cylindrical shape and axis OO, as well as a second part 23 of generally discold shape, which closes the end of the first part 22 opposite the body 10. Said second part 23 must of course be connected in leaktight manner to the first part 22. Such a sealed assembly can be produced for example by welding.

 According to an alternative embodiment, the cap 20 can also be in one piece.

 At its end adjacent to the body 10, the cap 20 is provided with a flange 24 bearing against an annular radial surface of the body 10.

 The cap 20 is tightened against the body 10 by means of bolts 50 passing through household bores in the flange 24, parallel to the axis OO, engaged in corresponding threaded bores formed in the body 10 parallel to the axis OO ,, and whose head comes to bear against an annular radial surface 25 presented by the flange 24.

 According to an alternative embodiment, the bolts 50 can be replaced by a threaded rod 51 passing through said bores provided in the flange 24, and engaged in the threaded bore of the body 10, as well as of a nut 52 tightened on the threaded rod 51 with interposition of a washer 53.

 It is easy to understand that by tightening such bolts 50 or nuts52, the cap 20 is tightly applied against the body 10. In this position, the connection between these two parts 10 and 20 is sealed by a weld schematically referenced 26, without input, lips machined on each of the parts 10 and 20.

 A socket 40 of generally cylindrical shape, the role of which will be explained in more detail in the remainder of this description, is inserted in the first part 22 of the cap 20.

Said sleeve 40 is provided on a portion of its outer periphery, with a thread 41 capable of engaging with a corresponding thread formed on the inner peripheral surface of said first part 22. On the other hand, an annular collar 42 provided for The lower end of the bush 40 has an annular radial bearing surface intended to come into abutment against a corresponding surface of the first part 22 of the cap 20, so as to block the bush 40 relative to the cap 20, when the thread 41 of this socket 40 is engaged in the corresponding thread of the cap 20.

 The cap 20 can thus be made of non-magnetic steel doped with boron, which makes it possible to produce a thin enclosure resistant to the pressure of the fluid.

We will now describe in more detail
the structure of the shutter 30 and of the displacement control members thereof.

As shown in the figure,
the shutter movement control members
tor include a screw 60 / nut 70 system.

Said nut 70 carries, on its periphery,
a plurality of permanent magnets of straight shape,
schematically represented in the figure and re
referenced 71.

Nut 70 fitted with permanent magnets
71 is carried at one of its ends by a stop
ball 72, resting and immobilized on the sleeve
40 above, opposite the body 10. At its other end (opposite the body 10), the nut 70 is provided with a bore in which is engaged a circular part 73. This part 73 protrudes beyond the nut 70, and bears against a stop 74 introduced into the bottom of a blind bore with an axis
OO formed in the second part 23 of the cap 20. This said blind bore also contains a circular surface 75, surrounding the end of the part 73 and ensuring the rotation of the latter.

 It is understood of course that the stop 74 and the bearing 75 must be made of particularly resistant material. For example, the stop 74 and the bearing 75 can be made of an alloy of cobalt, chromium and tungsten, and can be made in particular from a product sold under the registered trademark "STELLITE".

 A plurality of elastic washers 76 are introduced between the end of the part 73 housed in the nut 70, and a radial bearing surface provided on the latter.

 Such elastic washers can be constituted for example of washers of the so-called "BELLEVILLE" type.

 These elastic washers 76 allow axial compensation for differential expansions.

The permanent magnets 71 integral with the nut 70 are thus guided in rotation thanks on the one hand to the bearing surface 75, on the other hand to a bearing surface 77 forming a body with the ball bearing 72
The axial maintenance of the assembly is ensured, on the one hand by the stop 74, on the other hand by the ball stop 72, with the interposition of the elastic washers 76.

The cap 20 is coated with an outer part
schematically represented as lines
interrupted and referenced 80, which is suitable for
generate a rotating magnetic field.

Of course the air gap existing on the one hand between
the outer part 80 and the cap 20, on the other hand between the permanent magnets 71 and the cap
20 should be reduced. The same is true for the thickness of the wall of the cap 20. In this measurement, when said outer part 80 g -nbre * a magnetic field of rotary appearance, the coupling carried out with the permanent magnets 71 drives them in rotation , which communicates a translational movement to the aforementioned screw or rod 60, engaged by threading at 61 with the nut 70, and which is immobilized in rotation thanks to a key 62, integral with the rod 60, and engaged in a rectilinear groove 43, formed in said socket 40 parallel to the axis OO.

 Thus, as this is shown in the figure, the rod 60, threaded at its end opposite to the body 10, engages in the nut 70, passes through a cylindrical bore with an axis QO provided in the socket 40, and into which opens out. the rectilinear groove 43, and extends into a generally cylindrical chamber 44, which itself opens into chamber 15 of the aforementioned body 10, and which clocks the aforementioned shutter or valve 30, as well as a sheath 90.

 More specifically, the valve 30, of generally cylindrical shape consists of a body 31 provided on its outer periphery, on the side of the cap 20, an annular rib 32. This annular rib 32, which constitutes a flared head, opposite the seat 13 of the valve 30, is housed in the sleeve 90 which is carried sliding on the rod 60.

The valve 30 is thus capable of translation relative to the sleeve 90. However, such a movement is limited by an annular rib 91 provided on the internal periphery of the sleeve 90, on the side of the seat 13.

 More specifically, the sleeve 90 is composed of two parts 92 and 93, assembled by thread (at 94) so as to define an internal chamber 95 which houses the head 32 of the valve 30, as well as an annular rib 63 forming a bearing surface. support, provided on the outer periphery of the rod 60.

 It is easy to understand that the assembly in two parts of the sleeve 90 allows firstly to introduce the valve 30 and the rod 60 provided with its annular rib 63, in the first part 92, then after assembly of the second part 93, enclose the valves 30 and the annular rib 63.

A calibrated restriction 34 is provided between the valve 30 and the sleeve 90. This calibrated restriction 34 opens into a lumen
T 35 whose pressure drop is much lower than that of the calibrated restriction 34, and which communicates itself with the chamber 95 of the sleeve 90 housing the head 32 of the valve and the annular rib 63 of the rod, as well as with an axial bore 36 of axis OO, provided in the valve 30.

 As shown in the figure, in the valve closing position, the end 64 of the rod 60 adjacent to the seat 13, which preferably has a generally spherical shape, is capable of closing said bore 36 provided in the valve 30. In this position, the calibrated restriction 34 is in communication with one of the conduits, while the other conduit 11 is in communication with said bore 36 passing through the valve.

 As also shown in the figure, an elastic member 65 of the compression spring type is introduced into the chamber 95 of the sleeve 90, between the annular stop 63 of the rod 60 and the head 32 of the valve 30.

 According to the embodiment shown, the seat 13 is of generally conical shape, and the adjacent end of the valve 30 has a complementary shape.

 According to an important characteristic of the present invention, the permanent magnets 71 carried by the nut 70 are cobalt magnets and a rare earth metal preferably from the sanarium.

 On the other hand, said outer part 80, schematically represented in the figures, and adapted to generate a magnetic field of rotary appearance capable of driving the permanent magnets in rotation 71 is preferably made up of a set of permanent magnets mounted on the cap 20 and capable of rotation about the axis OO of the screw / nut system. The permanent magnets of the external part 80 will also preferably be magnets made of cobalt and of a rare earth metal, such as the sanarium.

 According to an advantageous embodiment, the external part 80 is removable, so that it can be used for different taps. In addition, the outer part 80 is preferably Iluflie of a torque limiter not shown in the figure.

 Of course, said outer part 80 can be rotated manually or by a motor.

 We will now describe the operation of the valve according to the present invention.

 When the outer part 80 is urged to cause the rotation of the permanent magnets 71 and of the associated nut 70 so as to bring the rod 60 closer to the seat 13, the latter comes to bear, at its end 64, against the upper edge of the bore 3 of the valve 30. The latter is then applied tightly against the seat 13 and eliminates any communication between the conduits 11 and 12, since the bore 36 is hermetically sealed. High pressure fluid, coming from the inlet duct 12 then flows through the calibrated restriction 34 and the T-shaped light 35 into the chamber 95 of the sleeve 90. The autoclave effect produced by the fluid which applies a pressure against the head 32 of the valve 30 and the force generated by the rod 60 make it possible to obtain perfect sealing of the assembly.

 When the outer part 80 is biased in the opposite direction, to ensure the distance of the threaded rod 60, relative to the seat 13, the valve 30, initially, remains in abutment against the seat 13, due to the high pressure present in the chamber 95, and thanks to the compression spring 65. Only the rod 60 is consequently displaced. As soon as the light in T35, opening into the bore 36 is released by the displacement of the rod 60, the fluid contained in the chamber 95 flows, by this light in T 35, towards the conduit 11. The pressure of the chamber 95 then corresponds to the pressure prevailing in the conduit 11. Under these conditions, when the annular rib 63 of the rod 60 comes to bear against the bottom 93 of the chamber 95 of the sleeve, the valve 30 can be moved away from the seat 13, and this with a limited maneuvering effort since the pressure prevailing on either side of the valve 30 is then balanced.

 It appears clearly on examining the figure, that the withdrawal of the valve 30 is caused by the cooperation of the annular ribs 32 and 91 required.

Of course, care should be taken to connect the conduit 12 to the inlet of the fluid, and the conduit 11 to the outlet of the fluid so as to obtain the abovementioned autoclave effect
The advantages provided by the valve according to the present invention are numerous.

As an example, we can cite
- system ensuring a watertightness towards the outside, of exceptional reliability, thanks to the continuous enclosure in which the threaded valve and its control members are placed, and to the magnetic coupling produced between the external part 80 and the magnets permanent 71,
- Reduced operating force since the valve 30 is subjected to pressures. balanced during the opening and closing operations,
security presented by the system, and in particular due to the impossibility of opening or closing the tap in the absence of possession of said appropriate external part 80,
robustness resulting from the absence of bellows at the level of the valve 30, as was the case in most of the devices previously used, and as described in particular in the United States patent No. 4,232,695,
- lack of fittings which results.

reduced maintenance and the elimination of corrosion attack on the valve stem.

Tests carried out on such. valve made it possible to demonstrate that it allows opening under a differential pressure at the shutter equal to 22.2 M Pa at a fluid temperature of 50 C. Tests have been carried out under general conditions of service according to the scales of variation of the fluid state parameters, as indicated below
pressure: 0 to 18 M Pa,
differential pressure: 0 to 18 M Pa,
temperature 4 20 to 340
These tests were fully satisfactory both in terms of sealing in sectioning and in terms of maneuverability.

 Of course, the present invention is not limited to the embodiment which has just been described from which it will be possible to envisage numerous embodiments in accordance with the spirit of the invention.

Claims (11)

 1. Faucet of the type comprising a body (10) into which open two conduits (11,12) capable of communicating with each other, and a cap (20), of non-magnetic material fixed in leaktight manner to the body to define a chamber (21 ) which houses a shutter (30) intended to interrupt the communication between said conduits, as well as members (60, 70) for controlling the movement of the shutter which comprise at least one permanent magnet (71) capable of being moved in rotation thanks to an external part (80) adapted to generate a magnetic field of rotary appearance, and a screw (60) / nut (70) system of which one of the elements is integral with the magnet - permanent to transform the movement of rotation of the permanent magnet in translation, characterized in that the shutter comprises a piloted valve (30), a chamber (95) provided opposite the seat (13) relative to the valve (30), and which communicates, via a calibrated restriction (34) with a first conduit (12) , and by means of a light (35) with the second conduit (11), this light being capable of being closed by a rod (60) displaceable in translation of the screw / nut system, when the rod applies the valve (30) against the seat and by the fact that the rod (60) is adapted to move the valve (30) away from the seat (13), after releasing the light (35) when the rod (60) is biased away from the seat.  2. Tap according to claim 1, charac terized in that the chamber (95) provided behind the valve is delimited by a sheath (90) carried sliding on the rod (60) and which houses the flared head (32) opposite at the seat (13) of the valve, said 1 light (35) opening into the; Xitc chamber (95) of the sleeve and into an axial bore (36) provided through the valve, this bore (36) being capable of being closed by the end (64) of the rod (60), the latter carrying an annular stop (63) housed in the chamber (95) of the sheath and capable of abutting against the bottom of the latter when the rod is biased away of the seat (13).  3. Tap according to claim 2, charac terized in that the end (64) of the rod (60) capable of closing the bore (36) passing through the valve (30), is of generally spherical shape.  4. Tap according to one of claims 2 and 3, characterized in that an elastic member (64) of the spring type is introduced into the chamber (95) of the sleeve (90), between the annular stop (63) of the rod (60) and the head (32) of the valve.  5. Tap according to one of claims 1 to 4, characterized in that said permanent magnet (71) is connected to an element (70) of the nut type while the screw (60) of the screw / nut system consists of said rod which is immobilized in rotation.  6.Faucet according to one of claims 1 to 5, characterized in that the screw system (60) / ecrout7Q) is carried in the cap (20) by means of elastic washers (76) which allow a axial compensation for differential expansions.  7. Tap according to one of claims 1 to 6, characterized in that the permanent magnets (71) are cobalt magnets and a rare earth metal.  8. Tap according to one of claims 1 to 7, characterized in that the cap (20) is assembled on the body (10) by bolts (50).  9. Tap according to one of claims 1 to 8, characterized in that the seal between the cap (20) and the body (10) is provided by a weld (26) of lip-seals.  10. Faucet according to one of claims 1 to 9, characterized in that said outer part (80) adapted to generate a magnetic field of rotary appearance consists of a set of permanent magnets, preferably removable , mounted on the bonnet (20) and capable of rotation around the axis (OO) of the screw / nut system.  11. Tap according to one of claims 1 to 10, characterized in that said outer part (80) capable of rotating the permanent magnets (71) housed in the cap (20) is provided with a torque limiter .