GB2279766A

GB2279766A - Remote controlled central heating

Info

Publication number: GB2279766A
Application number: GB9411737A
Authority: GB
Inventors: Iain Masterton
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-06-11
Filing date: 1994-06-10
Publication date: 1995-01-11
Anticipated expiration: 2014-06-10
Also published as: GB9312043D0; GB9411737D0; GB2279766B

Abstract

In a central heating system, control signals are passed from a central programmed control unit 10 to individual to-be-controlled devices 22 via the electricity ring main system 12. Dual Tone Multi Frequency (DTMF) or Frequency Shift Key encoding can be employed. Also disclosed is a motorised valve actuator (figure 3) that can be retrofitted on an existing radiator valve which can be used along with the control system to provide an automatically adjustable central heating system. <IMAGE>

Description

Automatic Control Svstem and Apparatus The present invention relates to an automatic control system and automatic control apparatus, particularly for domestic and/or office use. The system as described herein is particularly adapted for automatic control of a central heating system, but the invention is of more general application.

Conventional central heating programmers simply turn the system on and off at predetermined times of the day, and do not control individual radiators. For radiators to be controlled automatically from a central controller, it is necessary for appropriate motorised valves to be fitted, and for communication channels to be established between each radiator and the central controller for the passage of control signals to the motorised valves. Existing systems of this type employ motorised valves embedded in the pipework and dedicated wiring between the controller and the valves, and to any wall-mounted thermostats. These factors add to the expense of the system and the inconvenience involved in its installation, and are a disincentive to upgrading existing installations except where other substantial works are being undertaken at the same time.Further, such systems do not provide variable control of individual radiators. Typically, complete zones can only be turned fully on or fully off.

It is a first object of the present invention to provide a programmable control system which is suitable for domestic and/or office use and which may be installed at relatively low cost and with relatively little inconvenience. The system is suitable for use in controlling a central heating system but is applicable to other control functions.

It is a further object of the invention to provide a motorised valve actuator which is capable of being retro-fitted to existing radiators equipped with thermostatic valves.

In the preferred embodiment of a central heating control system in accordance with the invention, a further object is the provision of continuously variable control of individual radiators or groups of radiators.

In accordance with a first aspect of the invention, there is provided an automatic control system comprising a central controller for generating control signals in accordance with a predetermined program, transmitter means adapted for connection to a ring main forming part of an electric power supply and for superimposing said signals onto the supply current, and at least one receiver means adapted for connection to said ring main for receiving control signals generated by said controller and for generating output signals in response thereto.

Preferably, the control signals generated by the controller are Dual Tone Multi Frequency (DTMF) encoded signals or Frequency Shift Key (FSK) encoded signals.

Preferably also, said signals include addresses each identifying one of a plurality of devices or a group of devices to be controlled, and data comprising control instructions associated with such addresses. There may be individual receiver means associated with each of said devices, with a group of devices subject to common control and sharing a common address, with a group of devices subject to independent control and each having a unique address, or with a combination thereof.

Preferably also, the controller is a programmable computer.

Preferably also, said receiver means comprises filter means for extracting said signals from the supply current, decoding means and logic circuitry connected to said decoding means for generating said output signals.

Preferably, the receiver means is adapted to reject signals addressed to devices under the control of other receiver means and to generate said output signals in response only to signals including the address(es) of device(s) under its control.

Preferably also, said signals further include an initialisation signal, and said receiver means includes timer means whereby the receiver means is adapted to respond to said signals only if said initialisation signal, the correct address and said data are received within predetermined time periods.

The output signal from the receiver means may be used to control any of a number of devices, such as a motorised valve of a central heating radiator.

Preferably, said transmitter means and said receiver means are connected to the ring main by means of a conventional mains plug inserted in any ring main socket.

In accordance with a second aspect of the invention, there is provided a motorised valve actuator comprising a housing adapted for attachment to a radiator valve, said housing enclosing an electric motor and drive means adapted to be driven by said motor and to engage a rotatable control knob forming part of said valve so as to rotate said knob either clockwise or anticlockwise upon operation of said motor.

Preferably, said motor is a low-voltage DC motor.

Preferably also, said drive means is a friction drive including a friction idler adapted to engage said control knob. The control knob may be provided with a friction band for engagement by said idler.

Alternatively, the drive means may comprise toothed gears, worm screws or the like.

The valve actuator may be controlled such that the position of the control knob is continuously variable between its fully open and fully closed positions, and is particularly suited for use with an automatic control system in accordance with the first aspect of the invention to provide a complete central heating control system which is easily installed and is suited to retro-fitting to existing radiators.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. 1 is a schematic representation of a programmable central heating system in accordance with the invention; Fig. 2 is a block diagram of a receiver unit forming part of the system of Fig. 1; and Fig. 3 is a schematic representation of a motorised radiator valve actuator embodying the second aspect of the invention.

Referring now to the drawings, Fig. 1 illustrates a central heating control system in which control signals are generated by a central controller 10. The signals are encoded and superimposed on the supply current of a household ring main 12 by a transmitter unit 14 and are received by a receiver unit 16 which decodes the signals to control an actuator unit 18 to operate the valve 20 of a radiator 22. The central heating system would normally include a plurality of radiators, each with its own receiver unit and valve actuator. Groups of radiators might also be controlled by respective receiver units, all of the radiators in each group being subject to common control. Alternatively, a receiver unit might control a group of a radiators, each radiator in the group being subject to independent control via respective output channels from the receiver unit.

The controller 10 is suitably a microcomputer, possibly a "palm-top" type personal computer (PC). The control signals generated by the computer are transmitted to the actuator units of respective radiators, whereby individual radiators may be turned on and off automatically under program control and/or in response to direct manual input at the controller. The use of suitable actuators, an example of which is described below, will also allow continuously variable control of radiators between fully on and fully off. Program control may operate the valves in accordance with a predetermined timing sequence and/or in response to feedback from temperature sensors. The controller may also control the operation of the central heating boiler as in a conventional system.

In order to provide independent control of individual radiators or groups of radiators, the signals transmitted by the controller 10 include a unique address for each radiator or group, in addition to control instructions for the respective actuator devices.

Fig. 2 illustrates an embodiment of the receiver unit 16, for a system in which the transmitted signals are Dual Tone Multi Frequency (DTMF) encoded; i.e. "touchtone" telephone type signals. DTMF provides 16 tones which may be used to encode data.

In this embodiment, the receiver unit 16 comprises a front end demodulating filter 24 which extracts the transmitted signals from the supply current. The filter 24 is connected to the mains supply via a conventional mains plug inserted in any convenient socket, as is the transmitter unit 14. The output from the filter 24 is input to a DTMF decoder 26, which has 16 output channels 28, one for each of the DTMF tones. The output from the DTMF decoder 26 is interpreted by a logic circuit 30. One of the channels 28 provides a synchronisation signal which is applied to the SYNC input of the circuit 30. Two further channels correspond to instructions for the actuator to open or close the radiator valve, respectively, and are connected to inputs M and M" of the circuit 30. The remaining channels are available for address information.In this example, the address of each radiator consists of a unique pair of tone signals, the two corresponding output channels of the decoder 26 being connected to inputs A0 and Al of the circuit 30.

The circuit 30 has two output channels C and A, which respectively instruct the actuator to close or open the radiator valve.

Where the receiver unit 16 serves a group of radiators subject to common control, the output channels C and A supply control signals to the valve actuators of each radiator. Where the receiver unit 16 serves a group of radiators subject to individual control, the unit 16 would include separate logic circuits 30 for each radiator, each circuit 30 being connected to a pair of decoder output channels corresponding to the address of the respective radiator.

As can be seen from Fig. 2, the circuit 30 (which is illustrated schematically, showing only the principal logic components) will only generate an output signal C or A if a synchronisation signal and correct address signal are received along with the control signal.

Timer units 32, 34 and 36 hold the synchronisation and address signals on for predetermined periods after they are received, so that the unit will only respond if the correct set of signals is received within a predetermined time window.

The signals may be encoded by other coding schemes, suitably Frequency Shift Keying (FSK), using appropriate coding and decoding means.

In the present example, the actuator unit 18 controls the operation of a rotary control knob of a radiator valve. Accordingly, the instructions to open and close the valve comprise instructions to rotate the knob anti-clockwise or clockwise respectively. Since the duration of the corresponding DTMF tone can be determined by the controller 10, the extent to which the valve is opened or closed can be controlled substantially continuously between fully open and fully closed by varying the duration of the control tone.

The receiver unit 16 may also provide a power supply for the actuator device(s) 18 under its control, for example by including transformer means (not shown) providing a low voltage DC output.

The transmitter unit 14 comprises a DTMF encoder (not shown) having its input connected to an output from the controller 10, and a modulating filter (not shown) connected to the output of the encoder and connected to the ring main 12 in the same manner as the receiver unit 16. Alternatively, the controller 10 may generate DTMF signals directly, which are sent to the transmitter unit 14 and subsequently superimposed on the ring main via a modulating filter as above.

The signals generated by the controller, transmitted via the ring main and decoded by the receiver unit may be used for control functions other than the control of central heating radiators.

Fig. 3 shows an embodiment of a radiator valve actuator 18 embodying the second aspect of the invention, which is capable of being retro-fitted to existing radiators.

The actuator 18 comprises a housing 38 which is attached to the valve 20 of the radiator 22 by means of a clamp arrangement 40. The housing 38 encloses a low voltage DC electric motor 42, which may be driven in either direction in response to output signals from the receiver unit 16. A spur wheel 44 is fixed to the shaft of the motor 42 and drives a friction idler 46, which engages the rotatable control knob 48 of the valve 22.

A friction band 50 may be applied to the knob 48 to enhance the frictional coupling of the idler 46. The knob 48 can thus be rotated clockwise or anti-clockwise in response to signals generated by the controller 10.

The actuator 18 may be controlled, as by the control system described above, so as to vary the position of the control knob substantially continuously between fully open and fully closed. Other drive mechanisms besides friction drives may be substituted, such as toothed gears or worm screws.

Modifications and improvements may be incorporated without departing from the scope of the invention.

Claims

1. An automatic control system comprising a central controller for generating control signals in accordance with a predetermined program, transmitter means adapted for connection to a ring main forming part of an electric power supply and for superimposing said signals onto the supply current, and at least one receiver means adapted for connection to said ring main for receiving control signals generated by said controller and for generating output signals in response thereto.

2. A system as claimed in Claim 1 wherein the control signals generated by the controller are Dual Tone Multi Frequency (DTMF) encoded signals or Frequency Shift Key (FSK) encoded signals.

3. A system as claimed in Claim 1 or Claim 2 wherein said signals include addresses each identifying one of a plurality of devices or a group of devices to be controlled, and data comprising control instructions associated with such addresses.

4. A system as claimed in Claim 3 wherein individual receiver means are associated with each of said devices, with a group of devices subject to common control and sharing a common address, with a group of devices subject to independent control and each having a unique address, or with a combination thereof.

5. A system as claimed in Claim 3 or Claim 4 wherein the receiver means is adapted to reject signals addressed to devices under the control of other receiver means and to generate said output signals in response only to signals including the address(es) of device(s) under its control.

6. A system as claimed in Claim 5 wherein said signals further include an initialisation signal, and said receiver means includes timer means whereby the receiver means is adapted to respond to said signals only if said initialisation signal, the correct address and said data are received within predetermined time periods.

7. A system as claimed in any preceding Claim wherein the controller is a programmable computer.

8. A system as claimed in any preceding Claim wherein said receiver means comprises filter means for extracting said signals from the supply current, decoding means and logic circuitry connected to said decoding means for generating said output signals.

9. A system as claimed in any preceding Claim, wherein said transmitter means and said receiver means are connected to the ring main by means of a conventional mains plug inserted in any ring main socket.

10. A system as claimed in any preceding Claim wherein the output signals from the receiver means are used to control motorised valves of central heating radiators.

11. A motorised valve actuator comprising a housing adapted for attachment to a radiator valve, said housing enclosing an electric motor and drive means adapted to be driven by said motor and to engage a rotatable control knob forming part of said valve so as to rotate said knob either clockwise or anti-clockwise upon operation of said motor.

12. A motorised valve actuator as claimed in Claim 11 wherein said motor is a low-voltage DC motor.

13. A motorised valve actuator as claimed in Claim 11 or Claim 12 wherein said drive means is a friction drive including a friction idler adapted to engage said control knob.

14. A motorised valve actuator as claimed in Claim 13 wherein the control knob is be provided with a friction band for engagement by said idler.

15. A motorised valve actuator as claimed in Claim 11 or Claim 12 wherein the drive means comprises toothed gears, worm screws or the like.

16. A motorised valve actuator as claimed in any one of Claims 11 to 15 wherein said valve actuator is adapted to be controlled such that the position of the control knob is continuously variable between its fully open and fully closed positions.

17. A central heating control system comprising an automatic control system as claimed in any one of Claims 1 to 10 and a plurality of radiators fitted with motorised valve actuators as claimed in any one of Claims 11 to 16 wherein said valve actuators are controlled by said output signals from said receiver means of the automatic control system.

18. An automatic control system substantially as hereinbefore described with reference to Figs 1 and 2 of the accompanying drawings.

19. A motorised valve actuator substantially as hereinbefore described with reference to Fig 3 of the accompanying drawings.

20. A central heating control system substantially as hereinbefore described with reference to Figs 1,2 and 3 of the accompanying drawings.