Patent ID: 12228219

DETAILED DESCRIPTION OF THE INVENTION

FIGS.1to3represent a valve assembly10made in accordance with a first embodiment of the invention. The valve assembly10includes an expansion valve12which is inserted into a housing14arranged in a mounting body16.

The mounting body16includes an upstream conduit18, on the left when considering the figures, and a downstream conduit20, on the right when considering the figures, each opening into a portion of the housing14. Thus, the valve assembly10includes a fluid passage22formed by the upstream conduit18, the downstream conduit20, and the expansion valve12.

The housing14herein opens onto an upper face24of the mounting body16to enable the insertion of the expansion valve12into the housing14. An actuator26is herein mounted on the upper face24so as to be able to control the expansion valve12in the open or closed position.

In the remainder of the description, an orientation from upstream to downstream according to the fluid passage22will be used without limitation. Of course, the valve assembly10and the expansion valve12are intended to operate in both directions, so that the selection of downstream and upstream are arbitrary and are intended only to facilitate the description of the figures.

In a non-limiting manner, an axial orientation from upstream to downstream, according to the main axis A1of the expansion valve12, will be used, which corresponds to a vertical orientation from the bottom to the top, when consideringFIGS.1to3.

The expansion valve12comprises a tubular valve body28forming a main channel30along the main axis A1. The valve body28includes an upstream axial end section32which is provided with an upstream orifice34in communication with the upstream conduit18. The upstream axial end section32herein forms a substantially cylindrical base which is received in a complementary manner in the bottom of the housing14so that the upstream orifice34opens into the upstream conduit18. The upstream orifice34herein corresponds to the upstream axial end of the main channel30.

The valve body28includes a downstream axial end section36which is provided with at least one downstream orifice38intended to be in communication with the downstream conduit20, when the expansion valve12is in the open position, as illustrated inFIG.3. Advantageously, the downstream axial end section36herein includes four downstream orifices38which extend radially and which are distributed circumferentially every ninety degrees.

The expansion valve12is equipped with a shut-off device40which is movable relative to the downstream orifices38between a closed position, illustrated inFIG.2, and an open position, illustrated inFIG.3.

The shut-off device40includes a slider42which is mounted to slide axially on the downstream axial end section36of the valve body28, between the closed position in which an axial wall44of the slider42closes off the downstream orifices38and the open position in which the axial wall44of the slider42clears the passage between the downstream orifices38and the downstream conduit20.

The axial wall44of the slider42herein has a tubular cylindrical shape with a circular profile and thus delimits an internal cylindrical bore46.

The downstream axial end section36of the valve body28includes, in the vicinity of the downstream orifices38, a recess48intended to cause progressive and controlled expansion during opening of the expansion valve12. In the represented embodiment, the downstream axial end section36includes a frustoconical section50with an external diameter decreasing from upstream to downstream up to the downstream orifices38. Thus, the recess48is formed in the radial space delimited on one side by the frustoconical section50and on the other side by the cylindrical bore46.

The cylindrical bore46herein has a diameter slightly smaller than the largest diameter of the frustoconical section50so that, in the closed position, the axial wall44of the slider42could be in sealed contact with the base of the frustoconical section50, at the downstream axial end of the slider42. Hence, there is no fluid passage between the recess48and the downstream conduit20. The fluid originating from the main channel30is trapped in the recess by the axial wall44of the slider42and retained on the upstream side by the contact between the axial wall44and the valve body28, and on the downstream side by a radial sealing element52.

The sealing element52is herein arranged at the downstream axial end of the valve body28. It allows ensuring a static sealing and a dynamic sealing by slipping against the cylindrical bore46.

The sealing element52herein includes a friction ring54, preferably made of polytetrafluoroethylene, which is pressed against the cylindrical bore46by an elastic return element56. The elastic return element56is herein constituted by an annular seal made of an elastomeric material, or an O-ring gasket.

In particular, the friction ring54has the advantage of contributing to the axial sliding guidance by its friction against the slider42. According to the represented embodiment, the sealing element52is held axially on the downstream axial end section36by a holding element58, herein a washer crimped onto an axial extension60in the form of a cylindrical pin. The holding element58may be crimped thanks to a heading operation applied on the free end of the axial extension60.

The slider42herein includes, at its downstream axial end, a transverse plate62provided with a threaded hole64. The actuator26includes an actuation rod66herein forming a worm screw intended to cooperate with the threaded hole64so as to cause the movement of the slider42along the main axis A1.

Thus, when the actuation rod66is driven in rotation in the direction of screwing, it causes the axial sliding of the slider42from upstream to downstream, between the closed position ofFIG.2and the open position ofFIG.3. Conversely, when the actuation rod66is driven in rotation in the unscrewing direction, it causes the axial sliding of the slider42from downstream to upstream.

The transverse plate62herein extends by two transverse arms68which form an anti-rotation device for the slider42. These transverse arms68are received in complementary slides70arranged on the walls of the housing14, which allows guiding the slider42in the top portion72of the housing14during the rotation of the actuation rod66.

Of course, other actuation solutions and another anti-rotation device solution could be provided to replace those described herein.

Advantageously, the slider42includes at least one vent74, herein two vents74, which communicate the interior and the exterior of the slider42at the downstream end of the expansion valve12. The vents74herein consist of radial holes in the axial wall44, just below each transverse arm68.

Advantageously, the external diameter of the slider42, at the level of its axial wall44, is slightly smaller than the corresponding internal diameter of the housing14so as to enable a fluid passage from the downstream conduit20up to the top portion72of the housing14, and up to the interior of the slider by the vents74, regardless of the position of the slider42. This allows ensuring a pressure equilibrium on either side of the transverse plate62so that the actuator26has not a significant effort to supply during a phase of opening or closing the expansion valve12due to the pressure differential between the upstream conduit18and the downstream conduit20.

The operation of the valve assembly10according to the first embodiment is now described from the closed position which is illustrated inFIG.2.

In the represented example, in the closed position, it is considered that the upstream conduit18is at a first pressure P1different from the second pressure P2in the downstream conduit20. The valve assembly10according to the invention is capable of operating with a very significant pressure differential between the upstream conduit18and the downstream conduit20, for example a pressure differential of 160 bars.

In the closed position, the upstream conduit18, the main channel30, and the recess48are all at the same pressure, i.e. herein the first pressure P1. The sealed contact between the axial wall44and the base of the frustoconical section50, and the sealed contact between the friction ring54and the cylindrical bore46prevent the circulation of the fluid between the upstream and the downstream.

The downstream conduit20, the radial space76between the slider42and the housing14, the top portion72of the housing14, the interior of the slider42, are all at the same pressure, i.e. herein the second pressure P2.

When controlling the progressive opening of the expansion valve12, the actuator26causes sliding of the slider42downstream, i.e. upwards, when consideringFIGS.2and3. By sliding downstream, the slider42progressively uncovers the recess48which enables a progressiveness in the expansion of the fluid which begins to progressively pass from the upstream conduit18towards the downstream conduit20, or vice versa depending on the pressure differential.

It should be noted that the progressiveness of the expansion depends on the inclination of the wall of the frustoconical section50with respect to the cylindrical bore46. The lower this inclination, the more progressive the expansion will be. Indeed, the passage section of the fluid between the frustoconical section50and the cylindrical bore46increases progressively when the slider42moves downstream.

The slider42continues its travel up to the fully open position which is represented inFIG.3. Advantageously, in the fully open position, the slider42is offset axially downstream with respect to the downstream orifices38so as to completely uncover them and thus maximize the passage section of the fluid between the downstream and the upstream.

Of course, the valve assembly10operates similarly in the reverse direction, when the slider42moves from the open position towards the closed position.

Hence, the expansion valve12according to the invention has the advantage of being able to be bidirectional and enabling control of the expansion of the fluid either in the upstream to downstream direction than in the downstream to upstream direction. In a first case, the first pressure P1is higher than the second pressure P2, in a second case the first pressure P1is lower than the second pressure P2.

FIGS.4to6show a second embodiment of the valve assembly10according to the invention. We will now describe only the main elements that differentiate the second embodiment from the first one.

In the second embodiment, the valve body28has a cylindrical shape with a circular section and not a frustoconical section, as shown inFIG.6. The progressiveness of the expansion is obtained by arranging on the external axial wall of the valve body28a recess48in the form of a slot78which progressively widens downstream until reaching the height of the downstream orifices38. Thus, during an opening phase, the slider42first begins by uncovering the bottom of the slot78, which has a very small passage section, then the top of the slot78which has a larger passage section, until all downstream orifices38are uncovered, as illustrated inFIG.5.

The second embodiment also differs by the arrangement of the friction ring54and holding thereof on the valve body28. In this case, the friction ring54includes an internal annular groove80in which a portion of the elastic return element56is housed. The axial extension60of the valve body28herein includes an external annular groove82in which a portion of the elastic return element56is housed. The holding element58is herein constituted by a nut which is screwed onto the axial extension60, as a replacement for the crimped washer used in the first embodiment. In this second embodiment, the valve body28may include a surface forming a seat on which the slider42sealingly bears in its closed position.

The operation of the valve assembly10according to the second embodiment is identical to that described for the first embodiment.

LEGEND

10: valve assembly12: expansion valve14: housing16: mounting body18: upstream conduit20: downstream conduit22: fluid passage24: upper face26: actuator28: valve body30: main channel32: upstream axial end section34: upstream orifice36: downstream axial end section38: downstream orifice40: shut-off device42: slider44: axial wall46: cylindrical bore48: recess50: frustoconical section52: sealing element54: friction ring56: elastic return element58: holding element60: axial extension62: transverse plate64: threaded hole66: actuation rod68: transverse arm70: slides72: top portion74: vent76: radial space78: slot80: internal annular groove82: external annular grooveA1: main axisP1: first pressureP2: second pressure