GB2043212A

GB2043212A - Thermostatic flow control valve

Info

Publication number: GB2043212A
Application number: GB8001214A
Authority: GB
Original assignee: TRUCKTONICS Ltd
Current assignee: TRUCKTONICS Ltd
Priority date: 1979-01-12
Filing date: 1980-01-14
Publication date: 1980-10-01
Also published as: GB2043212B

Abstract

The valve (11) has a closure element movable in the normal way between open and closed positions under the influence of a thermostatic control head (25) for controlling, for example, the hot water supply to a radiator. The closure element is carried on a spindle (24) and the valve housing (33) includes stop means formed by a movable member (29) and an adjustable abutment (31). The movable member (29) is interposed between the thermostatic control head (25) and the closure element of the valve (11), and it moves with the closure element upon closure of the valve, the abutment (31) engaging the movable member (29) to limit movement of the closure element in the valve opening direction. <IMAGE>

Description

SPECIFICATION Thermostatic flow control valve This invention relates to thermostatic flow control valves for use in, for example, controlling the supply of hot water to radiators in central heating systems.

According to the present invention, there is provided a thermostatic flow control valve including a closure element which is movable between open and closed position5 under the influence of a thermostatic control actuator to control a flow, and including stop means comprising a movable mem ber, interposed between the control actuator and the closure element to move with the closure element upon movement of the latter to its closed position under the influence of the control actuator, and an abutment which cooperates with the movable mem berto limit the movement of the closure element towards its open position.

With this arrangement, the degree of movement of the closure element is limited by the stop means, and this is an advantage in setting up and balancing a system.

Desirably, the position of the abutment of the stop means is adjustable to vary the maximum possible degree of opening of the valve.

With this arrangement, the range of movement of the closure element is adjustable, and this allows a valve to have a variable KV factor.

There is also provided according to the present invention an attachment for a thermostatic flow control valve, the attachment being constituted by stop means comprising a movable member for location between a thermostatic control actuator of the valve and a closure element of the valve so as to move with the closure element upon movement of the latter to its closed position under the influence of the control actuator, and an abutment, for location within the valve so as to cooperate with the movable member to limit the movement of the closure element towards its open position.

Desirably, the dimensions of the attachment are such as to allow it to be fitted within a standard pattern of thermostatic radiator valve, without other modification of the radiator valve.

With this arrangement, the advantages of limited movement of the closure element can be conferred on existing systems, without the need to replace the existing thermostatic radiator valves.

The invention will now be described, byway of example, with reference to the accompanying draw ings, in which: Figure 1 is a part-sectional side elevational view of parts of a thermostatic water flow control valve according to one embodiment of the invention; Figure 2 is a plan view of parts of the valve of Figure 1; Figure 3 is a plan view of a cap and spindle, being parts of the valve of Figure 1, and Figure 4 is a part-sectional side elevational view of the cap and spindle of Figure 3.

Referring to the drawings, there is shown a thermostatic water flow control valve 11 for mount ing on a hot water supply pipe leading to a radiator.

The valve 11 has a closure element which is movable between open and closed positions such that it can close an aperture and so prevent hot water from reaching the radiator. Alternatively, when the closure element is moved away from the aperture to its open position, hot water can reach the radiator through the aperture. The closure element and aperture are of conventional form and are not shown in the drawings.

The valve 11 has a valve body 19, and a gland 21 is located on the valve body 19. The closure element of the valve is mounted on a spindle 24 which can slide through the gland 21. This sliding movement of the spindle 24 causes opening and closing movement of the valve closure element. In the illustrated example, downward movement of the spindle 24 as viewed in Figure 1 closes the valve 11, the closure element being acted upon by a biassing spring (not shown) which urges the closure element towards the open position, urging the spindle 24 upwardly as viewed in Figure 1.

Movement of the spindle 24 and the valve closure element is effected under the influence of a thermostatic control head 25 mounted on the valve body 19.

The thermostatic control head 25, in known manner, responds to changes in the ambient room temperature by causing movement of an actuator 27. The actuator 27 acts, through means to be described, on the spindle 24 to cause opening and closing of the valve. In the illustrated example the actuator 27 is displaced downwards in response to a sensed increase in ambient temperature.

Stop means for limiting the movement of the spindle 24 and, therefore, the valve closure element are provided within the valve 11. These stop means comprise a movable member, constituted by a cap 29 of top-hat cross-section, and an abutment, constituted by an externally screw-threaded ring 31. The cap 29 has a central part 43 and a peripheral part 45.

The ring 31 is screwed into a tubular housing 33 positioned within the valve 11 as shown. The housing 33 is constructed of plastics material, with an annular metal flange 35 at its base. Six ridges 37 (Figure 2) project radially from the flange 35 to locate the latter correctly within the valve body 19. The ring 31 may be made of either metal or plastics material.

The ring 31 has a central hexagonal aperture 39 (Figure 2) surrounded by a shoulder 41. The cap 29 has a central part 43 of circular cross section which can pass freely through the hexagonal aperture 39.

The cap 29 also has an annular peripheral part 45, surrounding the central part 43, which is prevented from passing through the aperture 39 by abutment against the shoulder 41. The cap 29 fits over the spindle 24, as shown in Figures 1 and 3.

In operation, the thermostatic control head 25 moves the actuator 27 in known manner in response to changes in the ambient room temperature. The actuator 27 acts through the cap 29 on the spindle 24. Thus when the actuator 27 moves downwards in response to a sensed increase in ambient temperature, the spindle 24 is pushed downwards to close the valve, the operation being essentially the same as that of a normal thermostatic radiator valve.

When the valve 11 opens, in response to a sensed decrease in ambient temperature, the first part of the opening movement of the closure element away from the aperture (that is to say upward movement, as seen in Figure 1, of the spindle 24) is unaffected by the cap 29 and the ring 31, as the central part 43 of the cap 29 enters the aperture 39 in the ring 31. After a certain amount of such movement, however, the peripheral part 45 of the cap 29 abuts against the shoulder 41 of the ring 31 and prevents any further opening movement of the spindle 24 and, therefore, of the valve closure element. This is the position shown in Figure 1.

The position of the ring 31 can be adjusted upwards or downwards, as seen in Figure 1, relative to the housing 33 by removing the head 25, engaging a suitable key in the hexagonal aperture 39 and rotating the screw-threaded ring 31. The adjusted position of the ring 31 will in turn predetermine the degree of opening of the valve at which the opening movement of the valve closure element is arrested by the stop means 29,31.

The valve 11 described above differs from a conventional thermostatic radiator valve (T.R.V.), in the provision of the stop means constituted by the cap 29 and the ring 31. The effect of these stop means is to limit the movement of the spindle 24 and its closure element, as described. In a conventional T.R.V. the spindle 24 travels through its full range of movement, limited only by back-seating of the closure element against the valve body 19, and in terms of temperature this full movement range is equivalent to a temperature differential of about 6"C.

On the other hand it is recommended that T.R.Vs.

should be sized and used with full movement of the spindle 24 equivalent to a temperature differential of 2"C. Hitherto there has been no means available to limit the movement of the spindle 24.

With the valve 11 described above, however, movement of the spindle 24 can readily be limited by the stop means to the equivalent of a temperature differential of 2"C or, of course, any desired temperature differential less than the full range (6"C). The valve 11 can be set with limited movement of the spindle 24 when it is installed in a system, and the system can then be balanced, and the volume controls set, in accordance with the performance of the valve 11 resulting from the limited movement of the spindle 24.

Furthermore, the KV factor of the valve 11 can be adjusted to any desired value by screwing in or out the ring 31, as described. Thus in a computer-sized radiator system, the rings 31 of the various radiators could be preset, so pre-balancing the system.

By using a T.R.V. as described above, on each ratiator, a central heating system can be balanced with only one valve on each radiator. With a normal two-pipe system employing conventional T.R.Vs. on the other hand, two valves on each radiator are needed, one for control purposes and one for balancing purposes. AT.R.V. as described above however can perform both functions. Hence it is possible to halve the number of valves and hence the locations where dirt can cause problems.

Clearing and cleaning of the valve 11 is not a problem, as once the thermostatic control head is removed the valve opens fully and becomes selfclearing and self-cleaning.

By restricting the movement of the valve to the equivalent of the desired temperature differential (for example 2"C) closer control of temperature can be achieved.

When installing a system, a dummy head can be put onto the valve 11 in place of the thermostatic control head. The system can then be balanced, and finally the thermostatic control head fitted to the valve 11.

In the case of installations where T.R.Vs. are used without auxiliary lockshield or balancing valves, the limitation of the movement of the valve not only enables a single valve to be installed on each radiator, as explained above, and used for balancing purposes, but also allows a cheaper valve to be used in place of the lockshield valve normally used in the U.K. For instance a ball valve, with a solely isolating function, could be used in place of a lockshield valve.

Claims

1. A thermostatic flow control valve including a closure element which is movable between open and closed positions under the influence of a thermostatic control actuator to control a flow, and including stop means comprising a movable member, interposed between the control actuator and the closure element to move with the closure element upon movement of the latter to its closed position under the influence of the control actuator, and an abutment which cooperates with the movable member to limit the movement of the closure element towards its open position.

2. A valve as claimed in Claim 1, wherein the position of the abutment of the stop means is adjustable to vary the maximum possible degree of opening of the valve.

3. A valve as claimed in claim 1 or 2, wherein the abutment has a central aperture through which one part of the movable member of the stop means can pass, and has a shoulder surrounding the central aperture against which another part of the said movable member abuts to limit the movement of the closure element towards its open position.

4. Avalve as claimed in Claim 2, in which the abutment is in screw-threaded engagement with a housing for adjustment of the position of the abutment.

5. Avalve as claimed in Claim 3 and Claim 4, in which the central aperture in the abutment is hexagonal to facilitate rotation thereof relative to the housing using a key.

6. An attachment for a thermostatic flow control valve, the attachment being constituted by stop means comprising a movable member, for location between a thermostatic control actuator of the valve and a closure element of the valve so as to move with the closure element upon movement of the latter to its closed position under the influence of the control actuator, and an abutment, for location within the valve so as to cooperate with the movable member to limit the movement of the closure element towards its open position.

7. An attachment as claimed in Claim 6, wherein means are provided for adjusting the position of the abutment and thus, in use, varying the maximum possible degree of opening of the valve.

8. An attachment as claimed in claim 6 or 7, wherein the abutment has a central aperture in it through which, in use, one part of the movable member can pass, and has a shoulder around the central aperture against which, in use, another part of the movable member abuts when iimiting the movement of the closure element towards its open position.

9. An attachment as claimed in claim 6,7 or 8, wherein the dimensions of the attachment are such as to allow it to be fitted within a standard pattern of thermostatic radiator valve, without other modification of the radiator valve.

10. A thermostatic flow control valve substantially as herein described with reference to and as shown in the accompanying drawings.

11. An attachment for a thermostatic flow control valve substantially as herein described with reference to and as shown in the accompanying drawings.