GB1576853A

GB1576853A - Thermal actuator units for valves

Info

Publication number: GB1576853A
Application number: GB23657/77A
Authority: GB
Original assignee: Danfoss AS
Current assignee: Danfoss AS
Priority date: 1976-06-05
Filing date: 1977-06-03
Publication date: 1980-10-15
Also published as: JPS5920069B2; DK146667B; DE2625421B2; DK146667C; JPS52150574A; FR2353896A1; DK242677A; FR2353896B1; DE2625421C3; DE2625421A1; SE7706461L

Description

(54) IMPROVEMENTS IN AND RELATING TO THERMAL AGl"UATOR UNITS FOR VALVES (71) We, DANFOSS A/S, a Danish company, of DK-6430 Nordborg, Denmark, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a thermal actuator especially for radiator valves.

The present invention provides a thermal actuator unit for attachment to a radiator valve, the unit comprising a thermally responsive actuating means housed in the unit and a manually operable knob for setting a desired temperature value; wherein an electric heating unit comprising a heating element is attached, by a ring to the knob of the actuator unit, the ring having a temperature setting scale and being releasably attached to the end of the knob so that there is heat transfer between the heating element and the actuating means through the aperture in the ring.

The heating element can be used to effect a night-time control of the actuator, for example: to shut down the valve.

A thermal actuator unit is known which has a thermally responsive actuating means, a manually operable knob for setting a desired temperature value and a cover ring for the knob having a temperature setting scale. Such a unit is illustrated in Fig. 1 of the accompanying drawing and can be converted to a unit according to the invention by attaching the heating unit to the knob. That may involve modification or even replacement of the existing cover ring but that is of no real consequence because that ring is a cheap component part of the actuator.

Even if the knob is turned to set the ,desired temperature, in which case the heating unit is rotated relative to the actuating means, the tolerances of the individual parts can be kept so small that the heating element is placed sufficiently dose to the end face of the power element. Application directly to it is not absolutely necessary because heat can also be applied by radiation.

With particular advantage, the heating element comprises a layer of resistance material on a plate which covers the central aperture and is connected to the ring. This leads to a comparatively large heating surface which can transfer heat to a correspondingly large part of the end face of the power actuating means and is able to transmit an adequate amount of heat by radiation with a low consumption of energy.

Preferably, a plate is provided which carries the heating element on one side and electric components for switching the heating element on the opposite side. In this way it is possible to effect switching on and off of the heating element directly at the actuator unit, regardless of whether this is by manual or by remote control. - Any connecting leads can therefore be plugged directly into an adjacent power point.

Although the individual parts of the heating unit can subsequently be connected to the ring, it is particularly favourable from the point of view of production if the ring and housing are permanently connected together with the plate interposed. The electrical components can then be pre-assembled, the ring taken from the normal production line for the aforesaid known actuator construction and the'three stated parts finally unified.

With this construction the electric connecting lead(s) for the heating element can also be conveniently lead out laterally between the ring and housing.

A thermal actuator unit for a radiator valve and constructed in accordance with the invention will now be described, by way of example only with reference to the accompanving drawing, wherein: Fig. 1 is a cross-section through a known thermal actuator unit shown attached to a known radiator valve; Fig. 2 is an exploded view of the actuator unit constructed in accordance with the invention; and Fig. 3- shows a circuit for the heating element of the actuator shown in Fig. 2.

Referring to the accompanying drawing, Fig. 1 shows a known regulating valve comprising a valve housing 1 (having an inlet and outlet) on which a known thermostatic actuator unit 2 is attached by means of a clamping device 3. A thermally responsive actuating means indicated generally at 4 comprises a rigid outer cup-shaped housing 5, which is rigidly connected by struts :6 to a clamped-on foot portion 7, and a flexible power element in the form of a inner bellows 8. The space defined between the housing 5 and the bellows 8 has a liquidvapour filling and acts as a temperature sensor. One end of the bellows 8 engages and/or is attached to a push rod 9, which rod is attached to a valve pin 10. The latter is operatively connected to the closure member (not shown) of the valve and serves to move it againt the force of a return spring (not shown).Engaging a shouldered end of the rod 9 (or the said end of the bellows 8 itself) is one end of an adjustable valve spring 11, the other end of which is supported on a retaining plate 12. The latter has an external screwthread 13 which engages a mating screwthread on a rotatable hollow operating knob or sleeve 14. The sleve 14 has a shoulder 15 abutting a corresponding shouldered portion 16 of the housing 5 of the actuating means under the force of the .spring 11. The sleeve 14 contains air slots 17. A cap 18 can be engaged on the sleeve 14 in any angular position by snapping it onto a plurality of circumferentially spaced tongues 19 provided at the end portion of the sleeve 14.

The cap 18 is in the form of a ring having has a central aperture which is substantially aligned with a projecting portion 20 of the end of the actuating means 4; a heat-conductive member 21 being mounted on the portion 20 and extending into and/or through the aperture in the cap 18. On the inner periphery of the skirt portion of the cap 18 there are two grooved or serrated rings 22 and 23 having abutments 24 which co-operate with a counter-abutment 25 on the actuating means 4 to define the minimum and maximum setting points of the sleeve 14. A scale (not shown in Fig. 1) is provided at the outer peripheral surface of the skirt portion of the cap 18 or possibly at its end face. An indicating arrow or the like for indicating how the actuator has been set is provided on the outer face of the member 21. The positions of the scale and indicator could, of course, be reversed.

Referring now to Fig. 2, which illustrates a thermal actuator unit constructed in accordance with the invention, it will be seen that this unit is basically the same in construction as that illustrated in Fig. 1 and similar parts are referenced accordingly.

The unit shown in Fig. 2 is additionally provided with a plate 26 which carries on one side a heating element 27 in the form of an electrical resistor layer e.g. a foil. On the other side various electrical components are assembled, namely a switching element 28 in the form of a transistor, a signal receiver comprising a transducer or sensing element 29, e.g. a light-sensitive resistor of a receiver controlling the switching element, a preliminary resistor 30 and possibly other parts as well. External electrical connecting leads 31 and 32 of a cable 33 are also attached to this plate. The cable 33 is connected directly to a main power point.

Further, there is a cap-like housing 34 which is arranged to cover the electrical components 28, 29 and 30 and the heating element 27. The housing 34 has an aperture 36 (the housing 34 being broken away at '35 in Fig. 2 to show that aperture) which exposes the sensing element 29 so that it can be influenced, for example if it is 'in the form of a light-sensitive resistor, by room illumination. The housing 34 is connected to the cap 18 with the plate 26 in between, the cable 33 being led out from between these parts. Such a combined cover can be applied to the sleeve 14 by the cap 18 which is again in the form of a ring.

A typical circuit for the components 27, 28, 29 and 30 is shown in Fig. 3. The heat- ing element 27 is in series with the collectoremitter path of the transistor 28. In parallel with this series circuit there is a second series circuit consisting of the preliminary resistor 30 and the photoresistor 29, an elegtrical lead extending from the junction 37. 'thereof to the base of the transistor 28.

The series circuits are in parallel- and both in series with a diode 38 between the connecting leads 31 and 32 which are supplied with the normal A.C. mains current. As long as the photoresistor receives light the transistor 28 is blocked (that is non-conductive).

When it becomes dark, the transistor 28 becomes conductive. This automatically ensures that the heating element 27 will become effective during darkness. The heat produced by the element 27 is to a large extent transmitted in the region of the central aperture 19 of the cover ring 18 to the projecting portion 20 or 21 of the end face of the operating element 4. As a result the operating element adjusts the position of the regulating valve, without manual resetting of the sleeve 14, to a position it would have taken up at a higher ambient (room) temperature. That is to say, the controlled ambient (room) temperature will be reduced in dependence on the amount of illumination of the element 27. Whenever the room is dark, there will be a reduction .in that temperature.

The valve will not only provide a lower controlled ambient temperature at night but also if a room is darkened because, for example, it is not in use. Further, a reduction in the controlled ambient temperature can also be effected manually by closing the aperture 36.

By way of example, with a heat output of 1 W an increase in the temperature of the operating element of roughly 10 C was obtained. This corresponded to a reduction in the controlled room temperature by about 6 to 8"C.

By appropriate selection of a signal receiver, the actuator unit can be controlled other than by light intensity. For example, sound waves or radio signals may be used to control the actuator unit if the receivers are appropriately constructed. If a radio call system is provided in a building, this may also be utilised for the central switching on and off of the heating elements.

The housing 34 can be releasably secured to the cap 18, for example, by snap-fitting, friction fitting or by bolts, screws or the like, or permanently secured, for example, by adhesive or the like, or by ultra-sonic welding or soldering The Complete Specification of our copending British Patent Application No.

23658/77 (Serial No. 1,576,854) relates to similar subject matter and reference is therefore directed to that Specification.

WHAT WE CLAIM IS:- 1. A thermal actuator unit for attachment to a radiator valve, the unit comprising a thermally responsive actuating means housed in the unit and a manually operable knob for setting a desired temperature value; wherin an electric heating unit comprising a heating element is attached, by a ring to the knob of the actuator unit, the ring having a temperature setting scale and being releasably attached to the end of the knob so that there is heat transfer between the heating element and the actuating means through the aperture in the ring.

2. A unit as claimed in claim 1, in which the heating element comprises a layer of resistance material on a plate, which covers the aperture in the ring.

3. A unit as claimed in claim 1, in which a plate is provided which carries the heating element on one side and electric components for switching the heating element on the opposite side.

4. A unit as claimed in claim 3, in which the heating element comprises a layer of resistance material on the plate.

5. A unit as claimed in any one of claims 1 to 4 in which the heating unit comprises a cap-like housing for the heating element, the housing being attached to the ring.

6. A unit as claimed in claim 5 when appendant to any one of claims 2 to 4, in which the housing and ring are permanently connected with the plate interposed between them.

7. A unit as claimed in claim 6, in which an electric connecting lead(s) for the heating element extends laterally between the ring and the housing.

8. A unit as claimed in any one of claims 1 to 7, in which the manually operable knob can be turned to set the desired temperature.

9. A unit as claimed in claim 8, in which the knob is axially fixed.

10. A unit as claimed in any one of claims 1 to 9, in which the manually operable knob has an open end which exposes part of the actuating means.

11. A unit as claimed in any one of claims 1 to 10, in which the manually operable knob is hollow and houses the actuating means.

12. A thermal actuator unit as claimed in claim 1, substantially as hereinbefore described with reference to and as illustrated by Figs. 2 and 3 of the accompanying drawing.

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Claims

**WARNING** start of CLMS field may overlap end of DESC **.

example, it is not in use. Further, a reduction in the controlled ambient temperature can also be effected manually by closing the aperture 36.

By way of example, with a heat output of 1 W an increase in the temperature of the operating element of roughly 10 C was obtained. This corresponded to a reduction in the controlled room temperature by about 6 to 8"C.

By appropriate selection of a signal receiver, the actuator unit can be controlled other than by light intensity. For example, sound waves or radio signals may be used to control the actuator unit if the receivers are appropriately constructed. If a radio call system is provided in a building, this may also be utilised for the central switching on and off of the heating elements.

The housing 34 can be releasably secured to the cap 18, for example, by snap-fitting, friction fitting or by bolts, screws or the like, or permanently secured, for example, by adhesive or the like, or by ultra-sonic welding or soldering The Complete Specification of our copending British Patent Application No.

23658/77 (Serial No. 1,576,854) relates to similar subject matter and reference is therefore directed to that Specification.

WHAT WE CLAIM IS:- 1. A thermal actuator unit for attachment to a radiator valve, the unit comprising a thermally responsive actuating means housed in the unit and a manually operable knob for setting a desired temperature value; wherin an electric heating unit comprising a heating element is attached, by a ring to the knob of the actuator unit, the ring having a temperature setting scale and being releasably attached to the end of the knob so that there is heat transfer between the heating element and the actuating means through the aperture in the ring.
2. A unit as claimed in claim 1, in which the heating element comprises a layer of resistance material on a plate, which covers the aperture in the ring.
3. A unit as claimed in claim 1, in which a plate is provided which carries the heating element on one side and electric components for switching the heating element on the opposite side.
4. A unit as claimed in claim 3, in which the heating element comprises a layer of resistance material on the plate.
5. A unit as claimed in any one of claims 1 to 4 in which the heating unit comprises a cap-like housing for the heating element, the housing being attached to the ring.
6. A unit as claimed in claim 5 when appendant to any one of claims 2 to 4, in which the housing and ring are permanently connected with the plate interposed between them.
7. A unit as claimed in claim 6, in which an electric connecting lead(s) for the heating element extends laterally between the ring and the housing.
8. A unit as claimed in any one of claims 1 to 7, in which the manually operable knob can be turned to set the desired temperature.
9. A unit as claimed in claim 8, in which the knob is axially fixed.
10. A unit as claimed in any one of claims 1 to 9, in which the manually operable knob has an open end which exposes part of the actuating means.
11. A unit as claimed in any one of claims 1 to 10, in which the manually operable knob is hollow and houses the actuating means.
12. A thermal actuator unit as claimed in claim 1, substantially as hereinbefore described with reference to and as illustrated by Figs. 2 and 3 of the accompanying drawing.