IES80745B2 - A controller - Google Patents

Abstract

A controller (1) for controlling a central heating system (2) which comprises four central heating circuits (5), each of which comprise a plurality of radiators and a circulating pump (6). Two boilers (7) supply hot water to the central heating circuits (5) through a central connector (8). The controller (1) comprises four first inputs (21) for connecting four thermostats (10) into the controller (1), and four second inputs (28) for connecting timer switches (15) into the controller (1). Four first outputs (23) are provided for connecting the four pumps (6) to the controller (1), and two second outputs (25) are provided for outputting power to the respective boilers (7). The circuit in the controller (1) is arranged so that the timer switches (5) are connected to the pumps (6) through the thermostats (10), and one or both of the boilers (7) are powered through the outputs (25) in response to any one of the pumps (6) being powered. Each pump (6) is controlled by a corresponding timer switch (15) and a thermostat (10). An isolating circuit (37) is provided in the controller (1) for preventing interconnection of the first inputs (21) and interconnection of the first outputs (23) when any one of the first outputs (23) are connnected to any one of the second outputs (25) for preventing backfeeding of power to the first outputs (23) from the second outputs (25). .

Description

A controller The present invention relates to a controller, and in particular, to a controller for selectively applying a signal or signals to a plurality of devices in response to one of two or more input signals, and in particular, though not limited to a controller for centrally controlling a central heating installation.

In general, hot water central heating systems comprise a hot water heating circuit comprising a plurality of radiators through which hot water is passed. A boiler heats the water which is delivered to the circuit, and a pump circulates the hot water through the circuit.

Typically, a timer is provided for switching on and off the central heating system at predetermined desired periods, and additionally, in general a thermostat or thermostats are provided for monitoring the temperature within a building heated by the central heating system which controls the operation of the pump. Such central heating systems are relatively simple and straight forward and do not require particularly complicated control circuitry. However, in larger central heating installations, for example, those used in commercial and industrial buildings, hotels and the like, many central heating circuits may be provided for heating different zones of a building, for example, separate q r Ο ϋ ·ί j central heating circuits may be provided for each floor of the building, the floors constituting the respective zones. Each circuit in general, is provided with a pump for circulating water through that circuit.

Additionally, a thermostat is normally provided on each floor for controlling the corresponding circuit of the relevant floor. In larger installations, more than one boiler may be provided. In such cases, it is desirable that the boilers should be arranged in such a way as to be able to supply all circuits, and where the requirements of the circuits can be met by one boiler, it is desirable that only one boiler should operate, and the other boiler or boilers should be switched in as required to cope with an increase in the heating load. This is possible using known methods, however, in general, known methods tend to be rather complicated to implement.

There is therefore a need for a controller for controlling a central heating system, which overcomes the problems of the prior art.

The present invention is directed towards providing such a controller for controlling a central heating system, and indeed other systems which require control.

According to the invention there is provided a controller for selectively applying a signal or signals to devices in respect of one of two or more input signals, the controller comprising at least two first inputs for receiving respective first input signals from corresponding first sources, at least two first outputs for outputting respective first output signals to corresponding first output devices, at least one second output for outputting a second output signal to a corresponding second output device, at least two first connecting means, one first connecting means for connecting each first input with a corresponding first output, at least two second connecting means, one second connecting means being provided for connecting each first input to the at least one second output, and an isolating means being provided for preventing interconnection of the first inputs, and for preventing interconnection of the first outputs when any one or more of the first inputs are connected to the at least one second output.

In one embodiment of the invention the isolating means is located in the second connecting means. Preferably, the second connecting means are connected to the at least one second output through the isolating means. Advantageously, the isolating means comprises an optocoupler, the second being connected to a power supply through a triac of the optocoupler, and each second connecting means is connected through a light emitting diode of the optocoupler.

Advantageously, a pair of optocouplers are provided for applying an AC supply to the second output during both half cycles of the AC supply.

Ideally, the first signals are AC signals, and the AC first signals are applied to the respective light emitting diodes of the optocouplers through diodes for preventing back feed of a first signal from one second connecting means to the other second connecting means. Ideally, a capacitor is provided in series with the light emitting diodes of the respective optocouplers.

In one embodiment of the invention the controller comprises at least two second outputs, and in an other embodiment of the invention the controller comprises four first outputs. Preferably, the controller comprises four first inputs.

In another aspect of the invention the controller is for controlling a central heating system, each second output being adapted for connecting to a central heating boiler, each first output being adapted for connecting to a pump of a central heating circuit, each first input being adapted for receiving a signal from a thermostat.

In a further embodiment of the invention at least two second inputs are provided for receiving second input signals, and preferably, a third connecting means is provided for connecting each first input to a corresponding second input so that the signal received on each second input is passed in series through a first source connected to a corresponding first input. Ideally, each second input is adapted for connecting to a timer.

In a further embodiment of the invention a third input is provided for receiving a mains electricity supply.

Additionally, the invention provides a central heating system comprising the controller according to the invention.

The invention will be more clearly understood from the following description of an embodiment thereof which is given by way of example only with reference to the accompanying drawings, in which: Fig. 1 is a circuit diagram of the controller according to the invention for controlling a central heating system, Fig. 2 is a circuit diagram illustrating the controller connected to a central heating system, Fig. 3 is a circuit diagram of a detail of the controller of Fig. 1, and Fig. 4 is a circuit diagram illustrating part of the central heating system.

Referring to the drawings there is illustrated a controller according to the invention indicated generally by the reference numeral 1 for controlling a central heating system 2 also according to the invention. Before describing the controller 1 in detail, the central heating system 2 will first be described.

The central heating system 2 comprises four central heating circuits 5 each of which comprise a plurality of radiators (not shown) which are connected together in the respective circuit 5 for heating four separate zones independently in a building (not shown). The connection of such central heating radiators in a central heating circuit will be well known to those skilled in the art. A circulating pump 6 is located in each central heating circuit 5 for circulating water through the corresponding circuit 5. A pair of boilers supply hot water to the central heating circuits 5 through a central connector 8. The circuits 5 are connected to the boiler 7 through the connector 8 so that each circuit 5 operates with its pump 6 independently of the other circuits 5. A pair of pumps 9 corresponding to the boilers 7, respectively, are provided for circulating water between the corresponding boilers 7, and the connector 8. The pumps 9 are powered from their corresponding boiler 7. Four thermostats 10 are provided in respective zones of the building which is heated by the central heating system 2 for monitoring the temperature in the respective zones which are heated by the circuits 5.

A timer 12 having four timer switches 15 is provided for controlling the times at which the respective pumps 6 of the circuits 5 are operated. The switches 15 of timer 12, and the thermostats 10 are connected by the controller 1 to the pumps 6 for operating the pumps 6 as will be described below.

The controller 1 comprises a printed circuit board 20 on which the circuit of the controller 1 is formed and components of the controller 1 are mounted. Four first inputs, namely, four first input terminals 21 are provided on the printed circuit board 20 for receiving signals from the respective thermostats 10 for controlling operations of the respective four circulating pumps 6. For convenience the four thermostats are designated by the reference numerals 10a, 10b, 10c and lOd, respectively. The corresponding pumps which the thermostats 10a, 10b, 10c and lOd, respectively, control are designated by the reference numerals 6a, 6b, 6c and 6d, respectively, and the first input terminals 21 for receiving signals from the thermostats 10a to lOd are designated by the reference 10 numerals 21a, 21b, 21c and 2Id, respectively. In this embodiment of the invention, as stated above, the zones in which the central heating circuits 5 operate are separately timed by the switches 15 of the timer 12.

For convenience the timer switches 15 which correspond to the zones corresponding to the pumps 6a, 6b, 6c and 6d are designated by the reference numerals 15a, 15b, 15c and 15d, respectively.

Four first outputs provided by first output terminals 23 provide for the outputting of power to the pumps 6.

The first output terminals 23 each comprise three terminal connections 24, for a live, neutral and earth supply to the respective pumps 6, and for convenience the first output terminals 23 which correspond to the first input terminals 21 are designated by the reference numerals 23a, 23b, 23c and 23d, respectively. In this embodiment of the invention two second output terminals 25 are provided for outputting a power supply to the respective boilers 7. Each second output terminal 25 comprises five terminal connectors 27 for connecting a live, neutral and earth supply to the boiler, as well as for receiving a pair of control wires from the corresponding boiler 7. For convenience, the second output terminals 25 are referred to as output terminals 25a and 25b, and these correspond with the boilers 7a and 7b, respectively. However, there is no relationship between the reference letters a and b on the second output terminals 25 and the boiler 7 on the one hand, and the pumps 6, thermostats 10 and timer switches 15 on the other hand. The pumps 9 which correspond to the boilers 7a and 7b are indicated by the reference numerals 9a and 9b, respectively. Since the pumps 9a and 9b are powered by a supply from their corresponding boiler 7a and 7b, on a boiler 7 being activated, its corresponding pump 9 is likewise activated for circulating hot water from the boiler 7 to the connector 8.

In this embodiment of the invention a third second output terminal 25c is provided which also comprises five terminal connectors 27 for connecting to a third boiler, should this be required.

Second inputs, namely, four second input terminals 28a, 28b, 28c and 28d are provided for receiving signals from the switches 15a, 15b, 15c and 15d, respectively, of the of the timer 12. Four third output terminals 30a, 30b, 30c and 30d are provided for outputting signals from the second input terminals 28a, 28b, 28c and 28d to the respective thermostats, 10a, 10b, 10c and lOd. A fourth input terminal 32 for providing an AC mains supply to the controller 1 is also provided, as is a fifth output terminal 34 for providing an AC supply to the timer 12.

A connector 35 of the circuit of the printed circuit board 20 directly connects a live terminal of the fourth input terminal 32 to the live terminal of the fourth output terminal 34, and the live conductor 35 also connects the live terminal of the fourth input terminal 32 to an isolating means, namely, an isolating circuit 37 for isolating one boiler 7 from the other, and for isolating the circulating pumps 6 from each other when one of the pumps 6 is powered. The isolating circuit is described in detail below.

A neutral conductor 38 connects a neutral terminal of the fourth input terminal 32 to the neutral terminal of the fourth output terminal 34 for providing a neutral supply to the timer 12. The neutral conductor 38 also provides a neutral supply to the neutral terminals of the first output terminals 23 and the second output terminals 25 for providing a neutral supply to the circulating pumps 6 and the boilers 7.

An earth conductor 39 connects the earth terminal of the fourth input terminal 32 to the earth terminals of the first and second output terminals 21 and 25, respectively, and the earth terminal of the fourth output terminal 34 to the timer 12.

Four conductors 40a, 40b, 40c and 40d of the circuit of the printed circuit board 20 connect the second input terminals 28a, 28b, 28c and 28d directly to the third output terminals 30a, 30b, 30c and 30d for directly connecting the timer switches 15a, 15b, 15c and 15d to the corresponding thermostats 10a, 10b, 10c and lOd, respectively. Four conductors 42a, 42b, 42c and 42d of the circuit of the printed circuit board 20 connect the first input terminals 21a, 21b, 21c and 21d with the live terminals of the first output terminals 23a, 23b, 23c, and 23d for connecting the thermostats 10a, 10b, 10c and lOd with the corresponding circulating pumps 6a, 6b, 6c and 6d, respectively. In this embodiment of the invention the live supply from the live terminal of the fourth input terminal 32 is connected to the respective pumps 6a, 6b, 6c and 6d through the timer switches 15a, 15b, 15c and 15d and the thermostats 10a, 10b, 10c and lOd, respectively.

The four conductors 42a, 42b, 42c and 42d of the circuit of the printed circuit board 20 also connect the first input terminals 21a, 21b, 21c and 2Id to input terminals 46a, 46b, 46c and 46d of the isolating circuits 37 which correspond to the second outputs 25a and 25b, for activating one of the boilers 7 and for preventing activation of any circulating pumps 6 which has not been activated by its corresponding timer switch 15 and thermostat 10.

Each isolating circuit comprises a pair of optocouplers 48 for the corresponding second output 25a or 25b. One optocoupler 48 operates with the positive half of the AC supply cycle, while the other optocoupler 48 operates with the negative half of the AC supply. The input terminals 46 are connected through diodes DI to D8, capacitors Cl and C2, and resistors R1 to R4 to light emitting diodes of the optocouplers 48 for activating corresponding triacs of the optocouplers 48 when the circuit formed by any of the diodes DI to D8, Cl and C2, and R1 to R4 is conducting, see Fig. 3. The triacs of the optocouplers 48 connect a live supply from the live conductor 35 to the corresponding live terminal of the second output terminals 25a and 25b.

Briefly, the negative half of an AC mains cycle follows a path from any one of the input terminals 46 through the corresponding diodes DI to D8, the corresponding capacitors Cl and C2, and corresponding resistors R1 to R4 to the optocoupler 48. Current conducted by a diode DI is blocked from the remaining input terminals 46 by diodes D3, D5 and D7. The relevant capacitor Cl presents a non-dissipative resistance to the AC current which is combined with the resistance of the resistor Rl. This drops the mains power to an acceptable level for the light emitting diode in the corresponding optocoupler 48. The light emitting diode in the relevant optocoupler 48 turns on when mains is applied to any of the input terminals 46, and in turn enables the triac of the corresponding optocoupler 48 to conduct. Diodes DI, D3, D5 and D7 inherently convert the negative half of the mains cycle to DC, which is presented to the capacitor Cl. If this condition is allowed to exist the capacitor Cl ceases to conduct the now negative DC potential. The resistor R2 and the diode D9 are used to supply a positive potential to the capacitor Cl during the positive half of the mains cycle for restoring the desired AC potential to the capacitor Cl. Thus, an input on any terminal 46 causes one of the boilers 7 to be activated, while at the same time isolating the remaining input terminals 46 from the signal applied to the one of the terminals 46.

In use, the controller 1 is connected into the central heating system 2 as already described. When the timer 12 activates any of the switches 15, and the corresponding thermostat 10 is also in the closed circuit condition, the corresponding pump 6 is activated by the controller 1. This in turn applies a signal to the corresponding input terminal 46 of the isolating circuit 37, which in turn activates one of the boilers 7, without applying a live signal to any of the other pumps 6 not already activated by their corresponding timer switch 15 and thermostat 10.

On a boiler 7 being activated its corresponding circulating pump 9 circulates hot water to the connector 8, which in turn is circulated through the relevant central heating circuit 5 by the corresponding circulating pump 6.

The advantages of the invention are many. A particularly important advantage of the invention is that it provides a simple, straight forward and uncomplicated system for connecting the electrical supply and the control of the electrical supply to pumps and boilers of a multi-zone central heating system.

The invention is not limited to the embodiment hereinbefore described which may be varied in Λ construction and detail.

Claims (5)

1. A controller for selectively applying a signal or signals to devices in respect of one of two or more input signals, the controller comprising at least two » 5 first inputs for receiving respective first input signals from corresponding first sources, at least two first outputs for outputting respective first output signals to corresponding first output devices, at least one second output for outputting a second output signal 10 to a corresponding second output device, at least two first connecting means, each first connecting means being provided for connecting a corresponding one of the first inputs with a corresponding one of the first outputs, at least two second connecting means, each 15 second connecting means being provided for connecting a corresponding one of the first inputs to the at least one second output, and an isolating means being provided for preventing interconnection of the first inputs, and for preventing interconnection of the first 20 outputs when any one or more of the first inputs are connected to the at least one second output.

2. A controller as claimed in Claim 1 in which the isolating means is located in the second connecting means, the respective second connecting means being • 25 connected to the at least one second output through the isolating means .

3. A controller as claimed in Claim 1 or 2 in which at least two second outputs are provided, and at least two second inputs are provided for receiving second input signals, at least two third connecting means 5 being provided, each third connecting means being for connecting a corresponding one of the first inputs to a corresponding one of the second inputs so that the signal received on each second input is passed in series through a corresponding one of the first sources 10 which is connected to a corresponding one of the first inputs .

4. A controller as claimed in any preceding claim in which the controller is adapted for controlling a central heating system, each second output being 15 adapted for connecting to a respective central heating boiler, each first output being adapted for connecting to a pump of a central heating circuit, each first input being adapted for receiving a signal from a thermostat, and each second input being adapted for 20 connecting to a timer.

5. A controller for selectively applying a signal or signals to devices in respect of one of two or more input signals, the controller being substantially as described herein with reference to and as illustrated 25 in the accompanying drawings. F.F. GORMAN & CO.