The present disclosure relates to valves and in particular to valve cocks. These cocks may be used in the field of changeover valves, such as those used for maintenance of filters, but may also be used for other types of valves.
Valves having a rotatable cock have been known for years. Generally, the valve body and the rotatable cock are both made of metal, and the fluid-tightness between the valve body and the rotatable cock is merely achieved by as little a clearance as possible between the valve body and the rotatable cock.
In an attempt to improve fluid-tightness, document WO 87/00598 A1 discloses a four-position valve comprising a valve body having several openings and a rotatable obstructing member also known as a rotatable cock. For preventing leakage when the cock obstructs an opening, a gasket is provided on a side of the cock. The gasket is held in position by an external member.
Although this system has proved satisfactory, there is still room for improvement. For instance, especially in small-sized valves, the external member itself may not remain in its desired position. Thus, after using the valve for a while, the fitting between the external member and the gasket may loosen, which may result in a change of position of the gasket in its seat, or in the external member protruding radially beyond the gasket. Therefore, in the long run, the sealing function of the valve may be affected.
As a consequence, there is a need for a cock which can prevent leakage in a more reliable manner.
This problem is solved by a cock according to claim 1. In an aspect thereof, the present disclosure relates to a cock for a valve having at least one opening for passage of fluid, the cock comprising a body configured to be movably mounted in a seat of the valve, at least one seal fastened to the body and configured to variably open or close the opening according to a position of the cock within the valve seat, wherein the seal is fastened to the body by an insert fitted between the seal and the body. The fluid may be a liquid or a gas, in particular water or oil. The valve may have at least two openings for the passage of fluid, namely at least one inlet opening and one outlet opening. The openings may be located about the seat of the valve so that the cock, more particularly its seal, is configured to variably open or close at least one of said openings according to a position thereof. In an embodiment, the body of the cock may be rotatably mounted in the seat of the valve and the seal may be configured to variably open or close the opening according to an angular position of the cock within the valve seat. In another embodiment, the body may be slidably mounted in the valve seat and the seal may be configured to variably open or close the opening according to a longitudinal position of the cock within the valve seat.
The seal may take the form of a gasket. The seal may be made of an elastomeric material. As an elastomer, the seal can deform and adapt to the shape of the valve seat around the opening, thereby providing satisfactory sealing with no leakage. In other embodiments, the seal may be made of a material configured to undergo running-in by actuation of the cock within the valve body. With such a material, the running-in allows to reach a very tight compatibility between the shape of the seal and the shape of the valve body, thereby providing satisfactory sealing with no leakage. For instance, the seal may be made of plastics.
The cock may comprise a plurality of seals, e.g. when the cock is required, in a certain position thereof, to seal a plurality of openings at the same time.
As indicated above, the seal is fastened to the body by an insert fitted between the seal and the body. When the cock includes plural seals, this may apply to some or all of them. That is, fastening means between the seal and the body include an insert. The insert may be made of a material other than the seal, e.g. plastics or metal (including alloys), in order to provide tight fastening between the seal and the body. The insert is fitted between the seal and the body, notably in a geometric sense. That is, at least a portion of the insert may have a first side in contact with the seal and a second side, opposite the first side, in contact with the body. The seal and the body may extend, respectively, beyond the first and second sides.
Thanks to the above-described structure, the seal is reliably fastened to the body, through the insert, and the insert may not protrude beyond the seal towards the opening. Therefore, leakage is reliably prevented. In some embodiments, the seal is assembled to the insert and the insert is fastened to the body. Thus, the seal, the insert and the body are, one to one, different parts exhibiting interfaces therebetween. Fastening means between the insert and the seal may include engagement of corresponding shapes, overmolding, bonding, e.g. through adhesive, etc. Fastening means between the insert and the body may include engagement of corresponding shapes, bonding, e.g. through adhesive, screws, etc.
In some embodiments, the insert is removably fitted on the body. Thus, when the seal is worn, it can be easily replaced by dismounting only the insert with the seal thereon and fastening a new seal onto the former body, through fitting of either the former insert or a new insert.
In some embodiments, means for fastening the insert to the body are accessible from a side opposite the seal with respect to the body. For instance, means for fastening the insert to the body may be accessible from a side longitudinally opposite the seal with respect to the body, or radially (i.e. perpendicularly to the axial or longitudinal direction) opposite the seal with respect to the body. In these embodiments, the means for fastening are not accessible on the sealing surface between the seal and the valve seat. This ensures that the means for fastening do not protrude beyond the seal towards the valve seat and do not interfere with the sealing function of the valve.
In some embodiments, the insert has an undercut for limiting separation of the insert from the seal. The undercut may be provided at an interface between the seal and the insert. The undercut of the insert may abut a portion of the seal (possibly an undercut too) in order to counter any movement trying to separate the seal from the insert. Therefore, the seal is more reliably assembled to the insert.
In some embodiments, the undercut comprises a negative draft angle of a cavity of the seal in which the insert is fitted. A draft angle is easy to manufacture and provides a large surface for the undercut, hence further improving reliability.
In some embodiments, the insert comprises at least one threaded hole. The hole may be a through hole or a blind hole. A threaded rod, e.g. a screw, may be inserted in the threaded hole of the insert for fastening the insert with respect to the body of the cock. The body may comprise a hole at a corresponding location, the hole being threaded or the body being clamped between the insert and a separate member, e.g. the screw head or a bolt.
In some embodiments, the insert holds at least a portion of the seal under compression load. That is, the insert exerts compression on a portion of the seal, e.g. by clamping such a portion between the insert and the body.
The position of the seal with respect to the body is accordingly better controlled and held.
In some embodiments, the seal extends beyond the insert towards the body. In other words, the seal may have a protruding portion, protruding beyond a side of the insert to be fastened to the body. When the insert is fastened to the body, the protruding portion must deform, whereby the insert holds the protruding portion of the seal under compression. In addition to better controlling the position of the seal with respect to the body, since the protruding portion may be provided at an interface between the seal and the body, the protruding portion enhances sealing and helps avoiding penetration of fluid between the body and the insert. In some embodiments, the body extends along a longitudinal direction and comprises a longitudinal wall, and the seal and the insert are mounted on one side of the longitudinal wall and the other side of the longitudinal wall defines a passageway for fluid. This structure is simple to manufacture and efficient.
In some embodiments, the longitudinal wall is offset with respect to an axis (e.g. axis of rotation) of the body. Preferably, the longitudinal wall is offset towards the seal, thus leaving more room for the fluid passageway. Pressure losses through the valve are thus reduced.
In some embodiments, the seal may have a closed contour surrounding the insert. In these embodiments, the above-described undercut may retain the insert within the seal, e.g. to make sure that the seal and the insert do not separate from each other. Further reliability of the cock is thereby obtained. More generally, the seal may define a blind cavity in which the insert is fitted, said cavity opening out towards an inner side of the body.
In some embodiments, a full surface of the insert is exposed to either the seal or the body. That is, the insert has no surface exposed to the fluid. In this way, sealing between the insert and the seal on the one hand, and the insert and the body on the other hand, is improved, and therefore the operation of the cock as a whole is made more reliable.
In some embodiments, the seal comprises a protruding sealing lip configured to surround said opening of the valve. Since the sealing lip is configured to surround the opening, and not necessarily to adapt to the exact shape of the opening, a single shape of sealing lip can be used for various designs of openings. In addition, compression of a sealing lip can be accurately controlled, whereby the sealing performances are enhanced. In some embodiments, the cock comprises a plurality of said seals and a plurality of said inserts, each of the seals being assembled to a corresponding one of the inserts to form a seal-insert set, the seal-insert sets being separated from one another, in a longitudinal direction of the body, by respective transverse separation walls of the body. Each seal-insert set may have some or all of the previously described optional features. This kind of cock is useful for multi-stage valves, such as double or triple valves. The transverse separation walls enables to separate the sealing functions of the respective seal-insert sets, thereby enabling different designs or different position configurations for each set and stage, but also partial replacement and maintenance of the cock. The cock body itself may comprise a plurality of assembled cock members, each of the cock members being associated to a corresponding seal-insert set.
In another aspect, the present disclosure also relates to a valve, in particular a three-way valve, comprising the cock as previously described. In yet another aspect, the present disclosure relates to a changeover valve comprising a primary fluid inlet, a first secondary fluid outlet and a second secondary fluid outlet, and a primary fluid outlet, a first secondary fluid inlet and a second secondary fluid inlet, and a cock as previously described, wherein the transverse separation wall is provided with a sealing member so as to isolate the primary fluid inlet, the first secondary fluid outlet and the second secondary fluid outlet from the primary fluid outlet, the first secondary fluid inlet and the second secondary fluid inlet, and the cock is configured to variably enable fluid passage from the primary fluid inlet to the first secondary fluid outlet and/or the second secondary fluid outlet, depending on the position of the body, and to variably enable fluid passage from the first secondary fluid inlet and/or the second secondary fluid inlet to the primary fluid outlet, depending on the position of the body. A changeover valve is an example of a double valve (or two-stage valve) as previously mentioned, wherein a first stage comprises the primary fluid inlet, the first secondary fluid outlet and the second secondary fluid outlet and a second stage comprises the primary fluid outlet, the first secondary fluid inlet and the second secondary fluid inlet.
The invention and advantages thereof will be better understood upon reading the detailed description which follows, of embodiments of the invention given as non-limiting examples. This description refers to the appended drawings, wherein:
A cock 100 according to a first embodiment is described in relation to
The cock 100 comprises a body 110 which is configured to be movably mounted in a seat of a valve. Here, the body 110 generally extends along the longitudinal direction X and is to be mounted in the valve seat so as to be rotatable about its longitudinal axis X. The cock 100 may comprise a key 112, integral with the body 110 or provided as a separate part fastened thereto, for controlling rotation of the body 110. In this embodiment, the key 112 is provided at one end of the body 110 in the longitudinal direction.
The body 110 comprises a longitudinal wall 114 extending along the longitudinal direction X. As can be seen more clearly in
Each stage of the body 110 thus defines, on one side of the longitudinal wall 114, a passageway for fluid (here on the side of the longitudinal wall 114 closer to the longitudinal axis X), and on the other side of the longitudinal wall 114, a housing for mounting a seal-insert set 120. In this embodiment, the mounting of the seal-insert set 120 is achieved through fastening means, e.g. screws 122, engaged in through holes 118 of the body 110 and fastened to corresponding means, e.g. threaded holes 124, of the seal-insert set 120. Here, the through holes 118 extend substantially radially through the longitudinal wall 114. Although three through holes 118, screws 122 and threaded holes 124 are represented for each stage in
The seal-insert set 120 comprises a seal 130 and an insert 140. The seal 130 may be an elastomeric seal or a plastic seal. For instance, the seal 130 may be made of at least one of polytetrafluoroethylene (PTFE), nitrile butadiene rubber (NBR), fluoroelastomer (e.g. fluorocarbon-based such as FKM or FPM), ethylene propylene diene monomer (EPDM) rubber, etc. The hardness of the seal 130 may range from 60 to 90 Shore A. However, other materials may be considered for the seal 130, depending on the application.
The seal 130 is configured to be fastened to the body 110, specifically in the housing defined at one side of the longitudinal wall 114. Thus, as the body 110 rotates, the seal 130 variably opens or closes openings of the valve, either partially or totally.
In order to provide a reliable fastening between the seal 130 and the body 110, the insert 140 is provided to be fitted between the seal 130 and the body 110. That is, the seal 130 is fastened to the body 110 through the insert 140. Removing the insert 140 would make the seal 130 and the body 110 independent from each other.
In this case, the insert 140 is made of metal, e.g. steel. However, other materials such as plastics are contemplated. In this embodiment, the seal 130 is overmolded onto the insert 140. In this case, the insert 140 should comprise, or even be made of, a material that withstands overmolding of the seal 130 thereon. Of course, other techniques are encompassed for assembling the seal 130 to the insert 140, which may involve different requirements for the seal 130 and the insert 140.
In order to improve adhesion between the seal 130 and the insert 140, a surface of the insert 140 to contact the seal 130 may be sandblasted or otherwise roughened (e.g. knurled) before combining the seal 130 to the insert 140. More generally, the insert 140 may have a greater surface roughness on surfaces to contact the seal 130 than on other surfaces thereof, e.g. surfaces to contact the body 110.
Furthermore, in order to prevent the seal 130 from separating from the insert 140, the insert 140 may have an undercut 142. For instance, as shown in
Thus, in this embodiment, the undercut 142 comprises a negative draft angle A of a cavity of the seal 130 in which the insert 140 is fitted. In an example, the draft angle A may range from 2° to 15°. Other types of undercuts are possible.
The threaded holes 124 are provided in the insert 140, which is generally made of a stiffer material than the seal 130. Therefore, the insert 140 provides a more reliable fastening of the seal 130 to the body 110. Furthermore, thanks to the screws 122 and although other fastening means may provide the same function, the insert 140 is removably fitted on the body 110. Rivets or the like may be used as fastening means, but they would prevent the insert 140 from being removed. In this embodiment, the threaded holes are blind holes extending in the insert 140 in a radial direction, but they may be through holes as well, depending on the required threaded length, and/or extend in any suitable direction.
In view of the above, the seal 130 is assembled to the insert 140 and the insert 140 is fastened to the body 110.
As shown in
A similar compression may be obtained without a protruding portion 136 of the seal 130, but with a protruding portion of the body 110, e.g. protruding towards the seal 130 by more than the available distance at rest. Thus, the protruding portion of the body 110 would put the seal under compression in a similar manner. However, this variant may make the manufacturing of the body 110 more complex, and thus more expensive.
In either case, it results that, as shown in
Besides, as represented in
A cock 100 according to a second embodiment is described in reference to
In order to fasten the seal 130 to the body 110, the seal 130 is first assembled to the insert 140, e.g. by overmolding. Then, the seal-insert set 120 is positioned in the housing, namely along the longitudinal wall 114 and between the transverse separation walls 116. Screws 122 are screwed into the through holes 118 of the body 110 and the threaded holes 124, from a side of the longitudinal wall 114 opposite the seal-insert set 120. Note that in this embodiment, the through holes 118 of the body 110 are configured to house the screw heads so that the screws 122 do not protrude beyond the longitudinal wall 114, in order not to impede the fluid flow in the valve.
As an alternative or in addition to the screws 122, at least one spring may be provided between the seal-insert set 120 and the body 110, in order to bias the seal 130 against the opening to seal (i.e. away from the body 110). For instance, the spring may comprise one or more spring washers arranged around a screw 122, in a gap between the body 110 and the insert 140.
Besides, as shown in
The cock 100 may be used in a valve such as that illustrated in
The changeover valve 80 also includes the cock 100 according to the first embodiment, however other embodiments of the cock, such as the second embodiment or yet another embodiment, could be used instead.
The cock 100 is rotatably mounted in the changeover valve 80 in a manner known per se in the art. The cock key 112 is provided with a protrusion 113 which may abut against a stopper 84 of the valve body, thereby defining the rotation range of the cock 100 within the valve seat.
As shown in
Use of the changeover valve 80 is illustrated in
Specifically, as mentioned before, the seal 130 may comprise a protruding sealing lip 138 configured to surround an opening of the valve, e.g. the second secondary fluid outlet 82B and the first secondary fluid outlet 82A. The sealing lip 138 may taper towards the opening (i.e. away from the insert 140), in order to increase its compression capability. A smooth transition between the sealing lip 138 and the remaining of the seal 130 may be provided, as shown in
Although one sealing lip 138 is illustrated, multiple sealing lips, successively surrounding the opening and/or adapted to various opening sizes and shapes, may be provided. Besides, a prestressed element (such as a V-shaped spring) may be embedded in the seal 130, e.g. below the sealing lip 138, to more accurately bias the sealing lip 138 towards the valve body.
As can be seen in the enlarged portion of
Part or all of these features may be applied to any or all of the openings which the sealing lip 138 is supposed to isolate in some operating conditions.
In the A-position shown in
Note that, as the first stage 82 is used for fluid to be filtered and the second stage 83 is used for filtered fluid, proper sealing between the two stages is advantageous. In this respect, sealing members such as the O-rings 104, 105 are helpful. More generally, as the first stage 82 and the second stage 83 are sealed from each other, they can be designed and handled differently, both from the point of view of the cock and from that of the valve body.
Furthermore, the seal in contact with unfiltered fluid wears more quickly than the seal in contact with filtered fluid. In this respect, as per the above explanations, it is advantageous that each seal can be replaced independently from each other.
The changeover valve 80 may be used with a different direction of fluid flow, and/or for other applications. The cock 100 according to different embodiments and its variations as previously described may also be used with different types of valves.
Although the present invention has been described by referring to specific exemplary embodiments, modifications may be provided to these examples without the departing from the general scope of the invention as defined by the claims. For instance, although the cock has been described as rotating in the illustrated embodiments, the skilled person would acknowledge that similar advantages can be obtained in a valve wherein the cock is slidably mounted and such embodiment is also encompassed. Besides, although some materials have been described, other materials may be envisaged, depending on the requirements of the intended application. More generally, individual characteristics of the different illustrated/mentioned embodiments may be combined in additional embodiments. Therefore, the description and the drawings should be considered in an illustrative rather than in a restrictive sense.
Number | Date | Country | Kind |
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21305667.4 | May 2021 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2022/062473 | 5/9/2022 | WO |