GB2486586A

GB2486586A - Fixing arrangement for a valve

Info

Publication number: GB2486586A
Application number: GB1121662.9A
Authority: GB
Inventors: Anders Oestergaard Clausen; Sonja Braun; Pia Laursen; Bjarne Frederiksen
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 2010-12-17
Filing date: 2011-12-15
Publication date: 2012-06-20
Anticipated expiration: 2031-12-15
Also published as: CN102606782B; FR2969245B1; GB201121662D0; DE102010054978A1; DE102010054978B4; CN102606782A; PL217655B1; PL397368A1; GB2486586B; RU2011150929A; FR2969245A1; RU2497036C2

Abstract

A fixing arrangement for securing a control element to a housing 3 of a heat exchanger valve comprises a threaded ring 5 having a first thread 6 with a thread axis and which surrounds the housing 3 and rests on a tightening surface 8 of the housing. A fixing element 11 having a second thread 12 which engages the first thread 8, is rotatable around the thread axis relative to the threaded ring 5 until a bearing surface 15 bears on the housing 3 and the housing 3 is clamped between the bearing surface 15 and the threaded ring 5. To achieve a reliable fixing of the conÂtrol element on the housing, the first thread 6 ends at a predeterÂmined distance from the bearing surface 15.

Description

Fixing arrangement for fixing a control element to a housing of a heat exchanger valve The invention concerns a fixing arrangement for fixing a control element to a housing of a heat exchanger valve with a threaded ring that comprises a first thread with a thread axis, surrounds the housing and rests on a tighten-ing surface of the housing and with a fixing element that comprises a second thread, which engages the first thread, the fixing element being rotatable around the thread axis relative to the threaded ring, until a bearing surface bears on the housing and the housing is clamped between the bearing surface and the threaded ring.

Such a fixing arrangement is known from a thermostatic valve element that is sold under the name of "Rondostat" by Honeywell AG, Offenbach am Main, Germany.

Such a fixing arrangement is, for example, required to ac-comrnodate a control element in the form of a thermostatic valve element on a radiator valve, the fixing geometry of the thermostatic valve element and the radiator valve, however, not matching each other. In this case, the threaded ring is arranged around the part of the valve housing, through which also an actuation tappet of the valve is led. In the known case, the threaded ring engages a projection on this part of the valve housing, so that it rests with a flange on the front side of the valve housing part. The actuating element is fitted on the ring and fixed by means of a nut that is screwed onto the first thread of the treaded ring.

S

However, it has turned out that in many cases this kind of fixing is not sufficient. Usually, it is required for the thermostatic head to be loadable by a force of 250 N with-out suffering damage. Often, this load limit is not achieved.

One embodiment of a valve, with which the fixing arrange-ment can, for example, be used, is known from CE 100 22 730 Al.

The invention is based on the task of enabling a reliable fixing of the control element on the housing.

With a fixing arrangement as mentioned in the introduc-tion, this task is solved in that the first thread ends at a predetermined distance from the bearing surface.

Thus, the mounting of the fixing element on the first thread is not limited by the fixing element coming to rest on the first thread. On the contrary, an area exists be-tween the end of the first thread and the bearing surface, said area being available for the generation of a certain tension. Accordingly, the housing can be clamped between the threaded ring and the bearing surface with a higher clamping force. The higher the clamping force, the larger (within certain limits) the forces, which the fixing of the control element can resist. In particular, the re-quired condition can be met that the end of the control element facing away from the valve can resist a pressure of 250 N without suffering damage. Here, the term "thread" must be interpreted broadly. It comprises all fixing ge-ometries, with which a rotary movement causes an axial tightening. In principle, also a helically extending pro- jection or a helically extending groove will be suffi-cient, with which the desired fixing is achieved after a rotation of, for example, 600 or 90°.

Preferably, the threaded ring ends at a distance from the bearing surface. It may be ensured that the threaded ring deforms between the end of the first thread and the bear-ing surface, when the threaded ring protrudes over the first thread. If, however, the threaded ring already ends at a certain distance from the bearing surface, an empty space will be available between the threaded ring and the bearing surface, into which the threaded ring can be moved further during tightening of the fixing element. This space does not have to be extremely large. It merely has to permit a movement of the threaded ring in the direction of the bearing surface, said movement being sufficient to reach the desired tightening force.

Preferably, the threaded ring has at least one opening in the circumferential direction. This makes it easier to fit the threaded ring on the housing. The threaded ring merely has to be resilient or deformable to a certain degree. It can then be opened so much that is can be guided over a projection on which the tightening surface of the housing is formed. After that the ring regains its shape. Because of the opening, the first thread is also interrupted in the circumferential direction. However, this is not criti-cal, when the first thread engages the second thread. In this state the opening is bridged by the second thread.

The threaded ring can also be made of several parts, which are arranged around the housing.

Preferably, the tightening surface is inclined in relation to the thread axis. Thus, the tightening surface forms some sort of cone. This has the advantage that the threaded ring tends to increase its diameter, when the fixing element is screwed together with the threaded ring an pulls the threaded ring in the direction of the fixing element. In this case, the threaded ring is expanded ra- dially by the inclined tightening surface. Thus, the en- gagement reliability between the first thread and the sec-ond thread is improved. The tightening surface does not have to be uninterrupted in the circumferential direction.

It is sufficient, if the threaded ring can rest on sec-tions or points of the housing.

Preferably, the threaded ring has a projection in the di-rection of the thread axis, said projection extending from the side of the bearing surface over a part of the hous-ing. However, this projection still has a certain distance from the bearing surface. The purpose of this projection is to ensure that, when the threaded ring is mounted on the housing, gravity or other forces cannot move it into a position, where it is not wanted and where the first thread is no longer able to engage the second thread. The projection can be relatively small.

It is preferred that in the area of the projection the housing is bevelled. This bevel, which is also made to be conical, makes it easier to push the threaded ring onto the valve housing. The bevel causes a radial expansion of the threaded ring, so that is can be pushed over the part of the housing, on which the tightening surface is formed.

I

Preferably, the bearing surface is formed on the fixing element. In this case, the fixing element is screwed onto the threaded ring, until it bears on the valve housing.

It is preferred that on the outside facing away from the housing, the fixing element has a fixing geometry. Thus, firstly the fixing element is fixed on the valve housing and then the control element is fixed on the fixing ele-ment.

In an alternative embodiment it may be provided that the bearing surface is formed on the control element. In this case, the control element is brought to rest on the valve housing and the fixing element clamps the control element directly against the valve housing.

Preferably, the fixing element is made as a union nut and the second thread is made as an internal thread. The nut then protects the first thread against damage and the first thread is no longer visible from the outside. This gives a more appealing appearance.

In the following, the invention is described on the basis of a preferred embodiment in connection with the drawings, showing: Fig. 1 a fixing arrangement according to the state of the art, Fig. 2 a first embodiment of a fixing arrangement ac-cording to the invention, and

I

Fig. 3 a second embodiment of a fixing arrangement ac-cording to the invention.

Fig. 1 shows a fixing arrangement 1 according to the state of the art (Rondostat from Honeywell AG, Offenbach, Ger-many).

A control element 2, for example a thermostatic valve ele-ment, is fixed on a valve housing 3. Only a part of the valve housing 3 is shown, namely the part, through which an actuation tappet for a valve element (not shown) is led. In connection with a radiator, a valve housing of this kind, for example, serves the purpose of controlling the flow of heating fluid through the radiator.

The valve housing 3 has a radially outwardly extending projection 4 that is used for fixing the control element 2.

In the area of the projection 4, a threaded ring 5 is fit-ted on the valve housing 3. The threaded ring 5 has a first thread 6 in the form of an external thread. The threaded ring 5 has a radially inwardly directed surface 7 that bears o a bottom side of the projection 4 that forms a tightening surface 8. In order to simplify the descrip-tion, the "bottom side" is the side facing away from the control element 2. A specific orientation in the room is not connected to this designation.

Further, the threaded ring 5 has a radially inwardly pro-jecting flange 9, which partly covers a front side 10 of the valve housing 3. This flange 9 ensures that, when -7-.

mounted on the valve housing, the threaded ring 5 does not change its position.

Additionally, the fixing arrangement 1 has a fixing ele-ment 11 that comprises a second thread 12 in the form of an internal thread. The fixing element 11 is made as a nut and comprises a radially inwardly extending flange 13 that engages a radially outwardly extending foot 14 of the con-trol element 2.

When the fixing element 11 is rotated in relation to the threaded ring 5 (and also in relation to the control ele-ment 2), the control element 2 with its foot 14 is pressed against the threaded ring 5. When this position has been reached, further screwing of the fixing element 11 is no longer possible. In this state, it is not necessarily en-sured that the surface 7 of the threaded ring 5 bears on the tightening surface 8 of the projection 4 with a suffi-cient force. When this force is not sufficient, it is not ensured that the control element 2 can resist external forces to the required extent, without risking damage of the fixing between the control element 2 and the valve housing 3. In order to remedy this problem, a solution ac-cording to the Figs. 2 and 3 is suggested.

In Figs. 2 and 3 the same and functionally the same ele-ments have the same reference numbers as in Fig. 1.

With the fixing arrangement 1 according to Fig. 2, the control element 2 rests directly on the valve housing 3 with a bearing surface 15. The threaded ring 5 rests with its surface 7 on the tightening surface 8 of the projec-tion 4. On the end facing the control element 2, the -8-S threaded ring 5 has a small radially inwardly extending projection 16 that bears on a conical wall section 17 of the valve housing 3, however, not engaging the front side of the valve housing 3. On the contrary, a distance 18 is provided between the end of the threaded ring 5 facing the control element 2 and the bearing surface 15 of the control element 2. This causes that the first thread 6 ends at a predetermined distance from the bearing surface 15.

Thus, a rotation of the fixing element 11 relative to the threaded ring 5 can provide a larger tension, with which the valve housing 3 is clamped between the threaded ring 5 and the bearing surface 15. A tightening is not prevented by the foot 14 of the actuating element 2 coming to rest on the threaded ring 5. On the contrary, a sufficient dis-tance 18 is provided here, which is merely filled with air or a compressible of resilient material. This means that the fixing element 11 can be tightened with a larger torque. This pulls the surface 7 of the threaded ring 5 against the tightening surface B of theprojection 4. As the tightening surface 8 is made to be inclined, that is, inclined or forming a cone in relation to the rotation axis of the fixing element and the thread axis of the two threads 6, 12, the threaded ring S will be radially ex- panded when being tightened in the direction of the con-trol element 2. This is also possible because, among other things, the treaded ring S has an opening (not shown) in the circumferential direction. This opening is advanta-geously also used for mounting the threaded ring 5 on the valve housing 3. The threaded ring S merely has to be somewhat radially expanded to enable it to be pushed over the projection 4. The more the fixing element 11 is tight-

S

ened, the more the surface 7 is pressed against the tight-ening surface 8 of the projection 4. This causes a radial expansion of the threaded ring 5, which thus bears very tightly on the inside of the fixing element 11.

This expansion is also supported by the conical design of the wall section 17. Its inclination starts at a radius that is smaller than the inner radius of the threaded ring in the resting state that it assumes under the influence of its own resiliency.

In the embodiment according to Fig. 2, the control element 2 is fixed directly at the valve housing 3, where it is also clamped.

The valve housing 3 with its projection 4 is also clamped between the control element 2 and the threaded ring 5. The distance 18 between the threaded ring 5 and the bearing surface 15 is dimensioned so that it is also available when applying the highest possible torque.

Fig. 3 shows a modified embodiment, in which the same and similar parts are provided with the same reference num-bers.

In the embodiment according to Fig. 3, the bearing surface is formed on the fixing element 11. Thus, initially the fixing element 11 can be fixed on the valve housing 3 without the control element 2, in that the fixing element 11, also here in the form of a union nut, is screwed onto the threaded ring 5.

S

-10 - On its upper side, the fixing element 11 has a fixing ge-ometry in the form of an additional thread 19, on which the control element can then be fixed. Of course, other fixing geometries are also possible.

It is possible to deviate from the shown embodiment in many ways. For example, the threaded ring 5 can comprise several parts that are arranged around the projection 4, so that the threaded ring 5 has several interruptions. The threaded ring S will then also be kept together by the fixing element 11. If the threaded ring 5 can be expanded, for example because it is made of an expandable material, an interruption can also be completely avoided in that the threaded ring 5 is expanded, guided over the projection 4 and then contracted again.

Aléo, the threaded ring S can firstly be mounted on the unit comprising the control element 2 and the fixing ele-ment 11 and then be placed and pressed onto the valve housing 3. Many geometry shapes also permit this fixing method, in particular when the projection 4 does not pro-ject too far over the valve housing 3.

Here, the term thread" is to be interpreted broadly.

Apart from the screw thread as shown, it also comprises all fixing geometries that permit an axial tension, when turning around an axis. For example, the thread can also be made as a helically extending groove (with only one thread or even less than one rotation of 360°) or a heli-cally extending edge. In the two latter cases, a rotation of substantially less than 360° will be sufficient to gen-erate the required clamping force.