GB1576854A

GB1576854A - Thermal actuator unit for valves

Info

Publication number: GB1576854A
Application number: GB23658/77A
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: DK146668C; JPS52150575A; DK242777A; DE2625420B1; FR2353897B1; DK146668B; DE2625420C2; FR2353897A1

Description

(54) IMPROVEMENTS IN AND RELATING TO A THERMAL ACTUATOR UNIT FOR VALVES (71) We, DANFOS 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 a radiator valve.

The present invention provides a thermal actuator unit for attachment to a radiator valve, the unit comprising a thermally responsive actuating means, a manually operable temperature setting knob, and a housing within which is arranged an electric heating element for heating the actuating means, a switching means for actuating the heating element and a transducer for receiving wireless signals as hereinafter defined and for controlling the switching means.

The term "wireless signal" means a signal transmitted to the transducer without wires and includes a light, sound, or radio signal.

By accommodating the switching means in the housing one no longer requires-as previouslya switching means that has to be installed in addition to, and externally of the actuator unit. Further, an electrical connecting lead between the switching means and the heating element is dispensed with.

A cable from the unit can be connected direct to a current source, e.g. the nearest power point.

With a plurality of such valves one can have individual switching of each valve to effect a drop in ambient temperature. However, it is also possible to conduct such switching centrally so that all the valves are switched together. In addition, the switching need not be effected by means of arbitrary signals; the signals can also be derived from particular physical parameters such as light intensity.

It is of particular advantage if the housing and the parts disposed in it form a unit which is releasably attached to the remainder of the actuator unit and, preferably, if that unit forms an and cover for the knob.

In this way one obtains an auxiliary unit which is ready for operation and provided with its connecting leads, the auxiliary unit being attachable to the actuator unit during production but also being attachable, subsequently to a thermal actuator which has no heating element and which has already been installed.

A particularly simple arrangement is achieved if a plate is provided which carries the heating element on one side and the switching means and transducer on the other side.

In particular, the heating element may comprise a layer of resistance material on the plate. This can be arranged over a large area closely adjacent the end of the thermally responsive actuating means so that a good heat transfer will be ensured.

Advantageously, the housing comprises a cover ring that can be placed on the knob and a cap connected to the ring, the plate being held between the ring and cap. The cover ring may conform to normal production and may for example carry adjustable rings with abutments on the inside that, together with a counter-abutment on the actuating means, limit rotary movement. All electric components may be pre-assembled on the plate. The cap serves as protection.

The assembly of these three parts is very simple. The auxiliary unit can then be attached to the end of the knob in the same way as a normal cover ring.

Preferably, the switching means is a transistor having its base voltage controlled by the transducer. Such a transistor is a small component that is easily accommodated in the housing and is able to operate the required heating energy of for example 1 W.

Modern transistors are, however, also operable above the usual mains voltage of 220 V.

Further, the transducer may be disposed adjacent to an aperture in the housing. Such a sensing element is then particularly easily reached by wireless signals.

The kind of transducer used depends on the nature of the signals. With particular advantage, the transducer is light-sensitive and preferably is a photoresistor. Switching on of the heating element then takes place in dependence on the light conditions in the heated room. As soon as the light is turned off at night, a night time reduction in heat is automatically applied. The same is true when in an office the blinds are drawn after office hours. The reduction in temperature can also be haphazardly effected by covering the aperture.

However, there are also other possibilities for the wireless signals, for example sound or radio waves. If, four example, a building is equipped with a radio communication system, in particular with a loop that passes through all the rooms, specially coded call signals can also be used for switching the valves.

A very simple circuit which is -particularly adapted to the limited space in the unit is obtained if the photoresistor and a preliminary resistor form a first series circuit, the heating element and collector-emitter path of the transistor form a second series circuit, the base of the transistor is connected to the junction between the photoresistor and preliminary resistor, and both series circuits are in parallel and connectible in series with a diode direct to mains voltage.

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 accompanying drawing, wherein: Fig. 1 is a cross-section through a known thermal actuator unit shown attached to a 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 unit 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 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 liquid-vapor 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 thè valve and serves to move it against 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 sleeve 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 a central aperture which is substantially aligned with a projecting portion 20 of the end of the operating element 4; a heat-con- ductive 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 cooperate with a counterbearing 15 on the operating element 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 resistance layer e.g. a foil. On the other side various electrical components are assembled, namely a switching elements 28 in the form of a transistor, a signal receiver comprising a transducer or a 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 mains power point. Further, there is a cap 34 which is arranged to cover the electrical components 28, 29 and 30 and the heating element 27. The cap 34 has an aperture 36 (the cap has been cut away at 35 in Fig. 2 to show this aperture) which exposes the sensing element 29 so that it can be influenced, for example if it is in the form of a lighf-sensftive resistor, by room illumi nation, The cap 34 is connected to.the cap 18 which together form a housing for the plate 26 which is arranged between them.

The cable 33 is led out from between these parts. Such a combined housing can be applied to the sleeve 14 in the same way as a simple cover ring 18.

A typical circuit for the components 27, 28, 29 and 30 is shown in Fig. 3. The heating 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 electrical 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 29. 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 cap 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 weldr ing or soldering.

The complete specification of our co-pending British Patent Application No. 23657/77 (Serial No. 1.576,853) 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, a manually - operable temperature-setting knob, and a housing within which is arranged an electric heating element for heating the actuating means, a switching means for actuating the heating element and a transducer for receiving wireless signals as hereinbefore defined, and for controlling the switching means.

2. A unit as claimed in claim 1, in which the housing and the parts disposed in it form a unit which is releasably attached to the remainder of the actuator unit.

3. A unit as claimed in claim 2, in which the unit including the housing forms a cover for the knob.

4. A unit as claimed in any one of claims 1 to 3, in which a plate carries the heating element on one of its sides and the switching means of its sides and the switching means on its other side.

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

6. A unit as claimed in claim 4 or claim 5, in which the housing comprises a ring which is attached to the end of the knob and a cap connected to the ring, the plate being held between the cap and ring.

7. A unit as claimed in claim 6, in which the transducer is covered by the housing and is disposed adjacent to an aperture in the housing.

8. A unit as claimed in claim 7, in which the transducer is light-sensitive.

9. A unit as claimed in claim 8, in which the transducer is a photoresistor.

10. A unit as claimed in any one of claims 4 to 9, in which the knob has an open end which exposes part of the actuating means, the plate being arranged adjacent that part of the actuating means.

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

12. A unit as claimed in claim 11, in which the switching element comprises a transistor having its base voltage controlled by the transducer.

13. A unit as claimed in claim 12 when appendant to claim 9, in which the photoresistor and another resistor form a first

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. nation, The cap 34 is connected to.the cap 18 which together form a housing for the plate 26 which is arranged between them. The cable 33 is led out from between these parts. Such a combined housing can be applied to the sleeve 14 in the same way as a simple cover ring 18. A typical circuit for the components 27, 28, 29 and 30 is shown in Fig. 3. The heating 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 electrical 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 29. 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 cap 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 weldr ing or soldering. The complete specification of our co-pending British Patent Application No. 23657/77 (Serial No. 1.576,853) 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, a manually - operable temperature-setting knob, and a housing within which is arranged an electric heating element for heating the actuating means, a switching means for actuating the heating element and a transducer for receiving wireless signals as hereinbefore defined, and for controlling the switching means.

8. A unit as claimed in claim 7, in which the transducer is light-sensitive.

9. A unit as claimed in claim 8, in which the transducer is a photoresistor.

series circit, the heating element and'the collector-emitter path of the transistor form a - second series circuit, the base of the transistor is connected to the junction between the photoresistor and the other resistor, and both series circuits are in parallel and connectible in series with a diode direct to mains voltage.

14. A unit as claimed in any one of claims 1 to 13, in which the manually operable member can be turned to set a desired temperature.

15. A unit as claimed in any one of claims 1 to 14, in which the manually operable member has air slots.

16. 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.