GB2408310A

GB2408310A - Radiator valve

Info

Publication number: GB2408310A
Application number: GB0425442A
Authority: GB
Inventors: Poul Hoelck; Arne Markvart; Tina Vassard Krogh
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 2003-11-20
Filing date: 2004-11-18
Publication date: 2005-05-25
Anticipated expiration: 2024-11-18
Also published as: PL205106B1; CN100398882C; CN1629522A; GB0425442D0; RU2004134661A; PL371224A1; GB2408310B; DE10354192A1; DE10354192B4; RU2296905C2

Abstract

A radiator valve (1) with a fluid passage control device in a housing (2), said control device having a movable element (4, 7), which can be actuated by a tappet (18) that is guided through an opening (19) in a housing part (10) of the housing (2) and is provided with a sealing arrangement. It is desired to facilitate reliable operation over a relatively long period. For this purpose, the sealing arrangement has only one seal (23) co-operating with the tappet (18), this seal (23) being accessible through a mounting opening in the housing part (10), which opening is covered by a cover (25).

Description

Radiator valve This invention concerns a radiator valve with a fluid

passage control device in a housing, said control device having a movable element which can be actuated by a tappet guided through an opening in a housing part of the housing and provided with a sealing arrangement.

A radiator valve controls the flow of a heat transfer fluid; usually water, through a radiator. For this purpose, a movable valve element is brought, to a greater or lesser degree, into proximity with a valve seat or bears on the valve seat. Actuation of the valve element occurs from the outside by means of an adjustment device.

The adjustment device can be operated manually. As a rule, however, the adjustment device is formed by a thermostatic valve top part.

In order to prevent escape of the heat transfer fluid from the radiator valve, the tappet is sealed with respect to the housing by means of a sealing arrangement. As the sealing arrangement has to seal the movable tappet, it is subject to a certain wear. This may cause the sealing arrangement to start to leak, which is of course undesirable.

In attempts to solve this problem, a number of proposals exist.

Thus, US 3,797,805 discloses a sealing arrangement for a valve tappet, in which a sealing ring surrounding a valve tappet is located on the side of a housing facing the valve element. On the side on which the tappet projects from the housing part, there is a further seal packing which does not effect a seal in the fault-free state, so that here the tappet can slide along without friction. When, however, the first seal starts to leak and water flows outwards along the valve tappet, this sealing arrangement swells. This causes an increase in the friction between this sealing arrangement and the tappet to such an extent that the tappet is virtually no longer movable. This is then an indication to the user that the seal has to be renewed. This approach does provide a certain security against fluid escape, but in the case of a fault the effect is that the radiator is no longer able to fulfil its function, because it can no longer be controlled.

DD 2 010 406 describes a sealing arrangement with a sealing chamber, in which is located a sealing ring, which co-operates with the tappet. Furthermore, the sealing chamber accommodates a guide bushing which is responsible for radial guidance of the tappet. A further sealing - 3 chamber is formed in the guide bushing, which chamber accommodates a further sealing ring. The sealing chamber is closed by a pressure screw which co-operates in the axial direction with a flat gasket element, thus closing the sealing chamber to effect a seal. When the sealing arrangement starts to leak, the pressure screw must be unscrewed; the guide bushing has to be unscrewed from the pressure screw, after which the two sealing rings can be replaced. This is a relatively complicated procedure.

Furthermore, this sealing arrangement is expensive to manufacture.

EP 0 699 985 A2 discloses a thermostatic valve for panel radiators, in which the tappet is sealed by several axially consecutive O-ring seals. The seals are not accessible from the outside. On the contrary, the space accommodating the seals is closed towards the outside by a wall, through which only the tappet projects. Exchange of the seals practically requires a complete dismantling of the valve.

DE 196 43 990 C1 discloses a further valve with a sealing ring that is located on the inside of the housing part through which the tappet projects. This sealing ring cannot be replaced. When this sealing ring starts to leak, a further sealing ring is inserted. For this purpose, the outside of the housing part is provided with - 4 - an annular chamber in which the additional sealing ring can be inserted. This additional sealing ring is, however, replaceable. The use of an additional sealing ring has, however, the disadvantage that the characteristics of the valve change, particularly the hysteresis, when a new sealing ring is inserted, because the tappet then has to overcome the frictional forces at two sealing rings. If, therefore, an additional sealing ring is used, the pattern of temperature regulation in the room being heated may change.

The invention is based on the problem of facilitating reliable operation over a long period.

The present invention provides a radiator valve with a fluid passage control device in a housing, said control device having a movable element actuatable by a tappet, the tappet passing through an opening in a housing part and being provided with a sealing arrangement, wherein the sealing arrangement has only one seal co-operating with the tappet, the said one seal being accessible through a mounting opening in the housing part, which opening is covered by a cover.

With a radiator valve as mentioned in the introduction, the abovementioned problem is solved in that the sealing arrangement has only the one seal co operating with the tappet, this seal being accessible - 5 through the mounting opening in the housing part, the opening being covered by the cover.

This construction facilitates easy replacement of the seal, when required. The seal is accessible through the mounting opening. The cover covers the mounting opening.

The cover has virtually exclusively the task of retaining the seal on the tappet. When the cover is removed, the defective seal can be removed, a new seal can be inserted and the cover can be closed again, that is, it can be fixed on the housing part again. The complete replacement procedure can be performed very quickly, so that there is no risk of large fluid losses in connection with the replacement. Because only a single seal is present, the friction between the tappet and the sealing arrangement is relatively small. The hysteresis remains small, because the tappet, when acted upon with forces in opposite directions, the tappet will have practically the same movement characteristic. Manufacturing costs can be kept small, as only slight outlay is required, both for the mechanical design and for assembly of the valve.

Preferably, the tappet is led through the cover with play, that is, it passes through it freely. Thus, the cover merely has the task of retaining the seal. It is not necessary for the cover itself to have a sealing function. - 6 -

Preferably, the cover is connected to the housing part by means of a snapfitting or a clamping connection.

This simplifies assembly. The cover merely has to be pushed onto the housing part and then sits with a stability sufficient for the function in question. The forces that could possibly act upon the cover by way of the seal are relatively small.

Preferably, the cover is non-rotatably connected to, or at least permits conjoint rotation to the required extent with, the housing part and has a torque application surface. In this case, the cover can be used to turn the housing part. This is particularly advantageous, when presetting of the radiator valve by means of the housing part is desired. A nonrotatable connection is easily achieved in that the engagement geometry between the cover and the housing part in the circumferential direction is not unchanging, but varies. This may, for example, be achieved in that in the region of the engagement geometry with the cover, the housing part has an angular shape or has ribbing or the like.

Preferably, the cover is made of plastics material.

This has several advantages. Firstly, the manufacture of a plastics cover is relatively cost effective. Secondly, plastics material is usually flexible or deformable to - 7 - such an extent that it can be fitted and retained on the housing part without major problems.

Preferably, on the outside of the opening, the tappet projects into an annular chamber, against whose inner wall the seal is biased. Thus, a part of the length of the tappet is additionally surrounded by a part of the housing, but at a distance therefrom. The seal is inserted in the annular chamber thereby formed the seal being clamped between the tappet and the inner wall of the annular chamber. Of course, the seal also bears sealingly on the tappet. This is a simple manner of achieving adequate fluid-tightness, which ensures that no heat transfer fluid can escape from the valve.

It is preferred that the annular chamber has an axial length which is greater than the thickness of the seal in a direction parallel to the longitudinal extent of the tappet. Thus, the seal is allowed to move together with the tappet in the annular chamber. This has energy advantages. The seal will move as long as the force required for the movement is smaller than the force required to overcome the friction.

Particularly advantageous is that the length of the annular chamber is at least twice as great as the thickness of the seal.

Preferably, the annular chamber is located in an extension of the housing part, the cover surrounding the outside of the extension. This improves the possibilities of fixing the cover on the housing part. If the cover is made to engage on the outside of the extension, the cover can be mounted on the housing part with a certain bias.

However, this bias also enables the cover to be removed again from the outside by means of a certain force. The force with which the cover is held on the housing part is at any rate sufficient to retain the seal.

It is preferred that on the outside of the extension the cover is shorter than the extension. In this case, a tool can be inserted between the cover and the housing so that, in a manner of speaking, the cover can be levered off the housing. This is advantageous, for example, if the cover has been on the housing for quite a while and the high temperatures present at the valve have caused the cover to stick to the housing.

Preferably, the cover projects into the annular chamber. The cover therefore clamps the wall of the extension annularly as it were, which further increases the retaining forces.

Preferably, a washer is held captive on the tappet.

The washer may be rotatable in relation to the tappet, but it cannot be removed from the tappet. It prevents the - 9 - tappet from being moved out of the housing part, which is particularly advantageous during transport, when it is not certain that the clamping forces exerted by the seal on the tappet will be sufficient. Furthermore, in the case of faults, the washer can be used for moving the seal out of the annular chamber by means of the tappet.

It is also advantageous if the movable element is provided with a leakage seal which co-operates with the housing from the inside. This leakage seal keeps the valve fluid-tight when the seal is being replaced. As soon as the force exerted by the tappet on the movable element ceases, because the tappet is removed from the housing together with the seal, the leakage seal engages the housing from the inside, thus providing a seal there, so that fluid can escape only for a short while, the valve, however, remaining fluid-tight in the long term.

Radiator valves constructed in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a schematic section through part of a radiator valve; and Fig. 2 shows a modified construction. -

Referring to the accompanying drawings, a radiator valve 1 has a housing 2, in which is located a valve seat 3, with which a valve element 4 co-operates. Together with the valve seat 3, the valve element 4 forms a fluid passage control device for a heat transfer fluid from an inlet 5 to an outlet 6. The amount of fluid passing through adapts, among other things, to the spacing between the valve element 4 and the valve seat 3.

The valve element 4 is retained on a valve shank 7, which is biased in the opening direction by a spring 8.

The spring 8 is supported on an insert 9, which is located in the housing 2.

A housing part 10 of cup-form construction is fitted on the insert 9 and further inserted in a gap 11 between the housing 2 and the insert 9. Here, the housing part 10 is sealed by means of a seal 12. The housing part 10 is held in the housing 2 by means of a bush 13, the bush 13 being screwed into the housing 2 and acting upon a circumferential projection 14 of the housing part 10.

The valve shank 7 has a circumferential projection 15, against which the spring 8 bears. On the side of the projection 15 remote from the spring 8, there is located a leakage seal 16 which is brought into engagement with an end wall 17 when the valve shank 7 moves to its upper end position in which the spring 8 has its greatest - 11 elongation. In this position, the leakage seal 16 and the end wall 17 form a seal which prevents fluid from escaping to the outside from the valve 1.

To actuate the valve shank 7, a tappet 18 is provided, the tappet being led through an opening 19 in the end wall 17. Beneath the opening 19, the end wall 17 can further have a recess 20, into which the upper end of the valve shank 7 can enter.

The housing part 10 has an extension 21, the wall of which surrounds the opening 19 and thus, at a distance therefrom, the tappet 18, so that an annular chamber 22 that surrounds the tappet 18 is formed.

In the annular chamber 22 is located a seal 23, for example in the form of an O-ring or a round cord seal, which is biased towards the inner wall 24 of the extension 21. In other words, the seal 23 is clamped between the tappet 18 and the inner wall 24 of the extension 21.

In a direction parallel to the longitudinal extent of the tappet 18, the annular chamber 22 has a relatively large length. This length is substantially greater, that is, at least twice as great as the thickness of the seal 23 in the same direction. Thus, under certain circumstances, a movement of the tappet 18 can also cause a movement of the seal 23. - 12

In order to prevent the seal 23 from moving out of the annular chamber 22, a cover 25 is provided. The cover is made of a plastics material. It can be mounted on the extension 21, where it is retained either by friction alone, or by means of retaining elements, for example engagement elements or snap-in connection elements (not shown). In the illustrated embodiment it is connected to the extension by means of a threaded connection 26. The cover 25 surrounds the tappet 18 with a certain play or freedom, that is, there is a gap between the cover 25 and the tappet 18. The cover 25 itself therefore has no sealing function.

In a direction parallel to the longitudinal extent of the tappet 18, the cover 25 is shorter than the extension 21, so that a gap (not shown) occurs between the cover 25 and the housing part 10, in which a tool can engage to remove the cover 25 from the extension 21 when the cover does not unscrew. For example, a screwdriver or a similar tool can be inserted and the cover 25 can be levered off as necessary.

The cover 25 surrounds the extension annularly on the outside, so that, in a manner of speaking, it is clamped on the extension 21. However, the cover 25 by means of an extension 27 also extends by a certain distance into the annular chamber 22. The extension 27 gives an additional - 13 fixing of the cover 25 on the extension 21. Furthermore, it permits a thickening of the cover 25, so that the cover can also adopt larger forces without being deformed.

Finally, the length of the cover 25 is sufficient to offer guidance to the tappet 18.

A washer 28 is fixed on the tappet 18. The washer 28 may be rotatable on the tappet 18 but it is not displaceable in the axial direction in relation to the tappet, that is, in the direction of the longitudinal extent of the tappet 18. Preferably, it is adhesively fixed to the tappet 18, or otherwise connected to form one piece with the tappet 18. Thus, the washer 28 defines two end positions, namely one end position, to which the tappet 18 can be retracted into the housing part 10, and another end position, to which the tappet 18 can be moved outwards. In this end position the washer 28 bears on the seal 23.

If now the seal 23 starts to leak, the replacement of the seal 23 can be made in a relatively simple manner as follows: The cover 25 is removed from the extension 21. A sufficient length of the tappet 18 is then accessible for it to be grasped and pulled out. The washer 28 is used as an auxiliary tool for moving the seal 23 out of the annular chamber 22. Without the force exerted by the tappet 18, the valve shank 7 is immediately pushed to its upper end position, so that the leakage seal 16 positions itself on the end wall 17 and the valve 1 is immediately sealed to the outside.

The tappet 18 can then be inserted again, but without applying force, and a new seal 23 can be inserted. As the inner wall 24 has a bevel 29 at the upper end, insertion of the seal 23 is simplified. Mounting or clamping of the cover 25 then pushes the seal 23 into its sealing position. The projection 27 is at least large enough for the seal 23 to be pushed over and beyond the bevel 29 into the annular chamber 22. The seal 23 therefore effects a seal when the cover 25 is mounted, before the leakage seal 16, 17 opens.

The cover 25 is able to provide conjoint rotation with the extension 21, that is, when the cover 25 is turned, the housing part 10 will also turn. In the case of a threaded connection of the cover 25, continued turning of the cover when screwed fully home serves to produce the conjoint rotation. Thus, the cover 25 can be used to change the presetting of the valve.

Fig. 2 shows a modified embodiment of a radiator valve, in which the same and functionally equal elements have the same reference numbers. -

Unlike the embodiment according to Fig. 1, the cover 25' is no longer fixed on the extension 21 by means of a screw thread. On the contrary, for fixing the cover 25 a spring washer 30 is provided, which engages in an inner circumferential groove 31 in the housing 2. The cover 25' has a corresponding outer circumferential groove 32, so that after pressing in the cover 25', a kind of catch or snap connection is achieved.

In a manner not shown, at least at one position on the circumference there may be a gap between the cover 25' and the housing 2, into which a screwdriver or another tool can be inserted to "lever off" the cover 25' from the housing 2.

The housing part 10 is non-rotatably connected with the insert 9, so that after removing the cover 25', turning of the extension 21 will also turn the insert 9, thus effecting presetting of the valve.

Claims

C L A I M S: 1. A radiator valve with a fluid passage control device in a

housing, said control device having a movable element actuatable by a tappet, the tappet passing through an opening in a housing part and being provided with a sealing arrangement, wherein the sealing arrangement has only one seal co-operating with the tappet, the said one seal being accessible through a mounting opening in the housing part, which opening is covered by a cover.
2. A valve according to claim 1, wherein the tappet passes freely through the cover.
3. A valve according to claim 1 or claim 2, wherein the cover is connected to the housing part by means of a snap-fixing connection.
4. A valve according to claim 1 or claim 2, wherein the cover is connected to the housing part by means of a clamping connection.
5. A valve according to any one of claims 1 to 4, wherein the cover is able to rotate conjointly with the housing part and has a torque application surface.
6. A valve according to any one of claims 1 to 5, wherein the cover is made of a plastics material.
7. A valve according to any one of claims 1 to 6, - 17 - wherein on the outside of the opening, the tappet projects into an annular chamber, against the inner wall of which the seal is biased.
8. A valve according to claim 7, wherein the annular chamber has an axial length which is greater than the thickness of the seal in a direction parallel to the longitudinal extent of the tappet.
9. A valve according to claim 7, wherein the length of the annular chamber is at least twice as great as the thickness of the seal.
10. A valve according to any one of claims 7 to 9, wherein the annular chamber is located in an extension of the housing part, the cover surrounding the outside of the extension.
11. A valve according to any one of claims 7 to 10, wherein on the outside of the extension the cover is shorter than the extension.
12. A valve according to any one of claims 7 to 11, wherein the cover projects into the annular chamber.
13. A valve according to any one of claims 1 to 12, wherein a captive washer is provided on the tappet.
14. A valve according to any one of claims 1 to 13, wherein the movable element is provided with a leakage seal which co-operates with the housing from the inside.
15. A radiator valve substantially as herein described with reference to, and as illustrated by, Figure I of the accompanying drawings.
16. A radiator valve substantially as herein described with reference to, and as illustrated by, Figure 2 of the accompanying drawings.