Patent Description:
Heating systems and cooling systems are known that comprise a fluid circuit through which a fluid circulates under pressure. An example of this type of system is a closed-circuit central heating system, in which system water flows in a loop from a boiler, through a series of hot-water radiators, and then back to the boiler. The system water may comprise a treatment additive, for example to reduce corrosion and/or to inhibit microbiological growths (bacteria or fungi), in addition to water, which may be supplied from a mains water supply.

When a system is connected to a mains water supply, it is desirable to prevent backflow, to avoid treated or contaminated water from entering the mains water supply. A way of achieving this involves utilising a "break" in the fluid flow path between the mains water supply and the fluid circuit. This may be provided by a water tank having an inlet connected to the water supply, an outlet connected to the fluid circuit, and a float-operated valve or other suitably controlled valve for selectively allowing water to flow from the mains into the water tank. An arrangement of this type is utilised in the boiler heated water system of Patent Publication No. <CIT>, in which a float operated equilibrium valve is used to always maintain a feed tank full of water from a mains water supply.

It is desirable to provide an improved arrangement for creating a "break" in the fluid flow path between the mains water supply and the fluid circuit.

According to a first aspect there is provided a method of supplying a liquid to a fluid circuit of a heating or a cooling system, the method comprising the steps of: (a) receiving a vessel provided with an inlet port, through which a liquid can enter the vessel in a direction of inflow, and an outlet port, through which a liquid can exit the vessel in a direction of outflow; (b) connecting the inlet port of the vessel to a liquid source via an inlet valve the inlet valve located upstream of the inlet port and operable to prevent or allow a liquid to enter the vessel through the inlet port, and connecting the outlet port of the vessel to the fluid circuit via an outlet valve, the outlet valve located downstream of the outlet port and operable to prevent or allow a liquid to exit the vessel through the outlet port, whereby a flow path between the liquid source and the fluid circuit extends through the vessel; (c) with the inlet valve open and the outlet valve closed, allowing liquid from the liquid source to fill the vessel; (d) with the inlet valve closed and the outlet valve open, allowing liquid within the vessel to drain; (e) with the inlet valve closed and the outlet valve closed, maintaining an air-filled interruption, within the vessel, between the liquid source and the fluid circuit.

A volume of air, contained with the vessel, is therefore usable to provide a "break" in the fluid flow path between the liquid source and the fluid circuit. However, this volume of air is temporarily and selectively replaceable, at least in part, with liquid from the liquid source for supplying to the fluid circuit.

Preferably, at step (c) or step (d) ultraviolet light is emitted to be incident on liquid flowing along said flow path.

In an example, at step (c) or step (d) an additive is supplied to liquid flowing along said flow path.

The liquid source may be a cold mains water supply.

According to a second aspect, there is provided apparatus for supplying a liquid to a fluid circuit of a heating or a cooling system, said apparatus comprising: a vessel provided with an inlet port, through which a liquid can enter the vessel in a direction of inflow, and an outlet port, through which a liquid can exit the vessel in a direction of outflow; an inlet valve located upstream of the inlet port and operable to prevent or allow a liquid to enter the vessel through the inlet port, and an outlet valve located downstream of the outlet port and operable to prevent or allow a liquid to exit the vessel through the outlet port, the inlet port connectable, via the inlet valve, to a liquid source for supplying the vessel with a liquid, and the outlet port connectable, via the outlet valve, to the fluid circuit for supplying the fluid circuit with a liquid, a flow path between a connected liquid source and a connected fluid circuit extending through the vessel; a controller operable to selectively open and close the inlet valve and the outlet valve, a non-transitory computer-readable medium, and program instructions stored on the non-transitory computer-readable medium that are executable by the controller to cause the controller to: (a) during a non-supplying mode of operation, maintain the inlet valve in a closed condition and maintain the outlet valve in a closed condition, for maintaining an air-filled interruption, within the vessel, between the liquid source and the fluid circuit; and (b) during a supplying mode of operation, to successively: (i) cause the inlet valve to be moved from the closed condition into an open condition, (ii) maintain the inlet valve in the open condition and maintain the outlet valve in the closed condition for a first period of time, for allowing the vessel to fill with liquid, (iii) cause the inlet valve to be moved from the open condition into the closed condition, (iv) cause the outlet valve to be moved from the closed condition into an open condition, (v) maintain the inlet valve in the closed condition and maintain the outlet valve in the open condition for a second period of time, for allowing the vessel to drain of liquid, (vi) cause the outlet valve to be moved from the open condition into the closed condition.

Preferably, the apparatus further comprises a light source operable to emit ultraviolet light incident on a liquid flowing along said flow path between a connected liquid source and a connected fluid circuit.

The controller may be operable to selectively turn the light source on and off, and the program instructions stored on the non-transitory computer-readable medium are executable by the controller to cause the controller to: maintain the light source in an off condition during the non-supplying mode of operation, and maintain the light source in an on condition during the supplying mode of operation.

The apparatus may further comprise a dosing valve for connection to an outlet of an additive reservoir, the dosing valve operable to supply an additive from the additive reservoir to a liquid flowing along said flow path between a connected liquid source and a connected fluid circuit.

The apparatus may further comprise a pump operable to move liquid along said flow path between a connected liquid source and a connected fluid circuit.

The controller may be operable to selectively turn the pump on and off, and the program instructions stored on the non-transitory computer-readable medium are executable by the controller to cause the controller to: maintain the pump in an off condition during the non-supplying mode of operation, and maintain the pump in an on condition during a period of the supplying mode of operation.

The apparatus may further comprise a sensing arrangement for providing an indication as to the level of liquid within the vessel.

A determination that the vessel has filled, or emptied, to a sufficient extent may be made based on a reading output to the controller from a sensing arrangement for providing an indication as to the level of liquid within the vessel and/or on a signal generated by a timer comprised by the controller.

The apparatus may further comprise a pressure sensing arrangement for providing an indication as to the pressure of system liquid within a connected fluid circuit.

An initiation of the supplying mode may be made based on a reading output to the controller from a pressure sensing arrangement for providing an indication as to the pressure of system liquid within a connected fluid circuit.

According to a third aspect, there is provided a heating or a cooling system comprising the apparatus of the second aspect. In an example, the liquid source is a cold mains water supply.

Further particular and preferred aspects of the invention are set out in the accompanying dependent claims.

The present invention will now be more particularly described, with reference to the accompanying drawings, in which:.

Illustrative embodiments and examples are described below in sufficient detail to enable those of ordinary skill in the art to embody and implement the apparatus described herein. It is to be understood that embodiments and examples can be provided in many alternate forms and the invention should not be construed as limited to the embodiments and examples set forth herein but by the scope of the appended claims.

In addition, features referred to herein in the singular can number one or more, unless the context clearly indicates otherwise. Similarly, the terms "comprises", "comprising", "includes", "including", "has" and/or "having" when used herein, specify the presence of the stated feature or features and do not preclude the presence or addition of one or more other features, unless the context clearly indicates otherwise.

In the following description, all orientational terms, such as upper, lower, radially and axially, are used in relation to the drawings and should not be interpreted as limiting on the invention, unless the context clearly indicates otherwise.

Apparatus for supplying liquid to a fluid circuit of a heating or a cooling system is shown in <FIG>. The apparatus is usable to supply a liquid from a liquid source to a fluid circuit of a heating or a cooling system. In an example application, the apparatus <NUM> is utilised to supply a top-up liquid to the fluid circuit of the heating or the cooling system.

Apparatus <NUM> is arranged to receive liquid from a liquid source <NUM>, via a fluid conduit <NUM> connected to the liquid source <NUM>, which may be a mains water supply, in a direction of inflow <NUM>, and to supply liquid to a fluid circuit <NUM>, which may be a fluid circuit of a heating or a cooling system, via a fluid conduit <NUM> that is connected to the fluid circuit <NUM>, in a direction of outflow <NUM>.

The apparatus <NUM> comprises a vessel <NUM> that defines an inlet port <NUM>, through which liquid can enter the vessel <NUM> in the direction of inflow <NUM>, and an outlet port <NUM>, through which liquid can exit the vessel <NUM> in the direction of outflow <NUM>. The inlet port <NUM> is provided with an inlet valve <NUM>, which is located upstream of the inlet port <NUM> and is operable to prevent or allow a liquid to enter the vessel <NUM> through the inlet port <NUM>. The outlet port <NUM> is provided with an outlet valve <NUM>, which is located downstream of the outlet port <NUM> and is operable to prevent or allow a liquid to exit the vessel <NUM> through the outlet port <NUM>.

In an example, the vessel <NUM> is closed with the exception of the inlet port <NUM> and outlet port <NUM>.

The apparatus <NUM> further comprises a controller <NUM>. The controller <NUM> is operable to selectively open and close the inlet valve I I I and the outlet valve <NUM>. The controller <NUM> is operable to control steps in a method of supplying liquid to a fluid circuit of a heating or a cooling system, for example top-up liquid.

In an example, the liquid source <NUM> is a cold mains water supply.

According to a method of supplying liquid from the liquid source <NUM> to the fluid circuit <NUM>: in a first step, with the outlet valve <NUM> closed and the inlet valve <NUM> open, liquid enters into the vessel <NUM> from the liquid source <NUM>; in a second step, the inlet valve <NUM> is closed; in a third step, the outlet valve <NUM> is opened and, with the outlet valve <NUM> open and the inlet valve <NUM> closed, the liquid that entered the vessel <NUM> during the first step exits the vessel <NUM>; in a fourth step, the outlet valve <NUM> is closed, creating a "break" between the inlet valve I I I (on the liquid source <NUM> side) and the outlet valve <NUM> (on the fluid circuit <NUM> side) by means of the vessel <NUM> being empty of liquid. If further liquid is to be supplied from the liquid source <NUM> to the fluid circuit <NUM>, in a fifth step the inlet valve <NUM> is opened and the first step commences again. Thus, the vessel <NUM> is used to create an air gap to inhibit undesirable backflow of liquid into the liquid source <NUM>, which is especially important when the liquid source <NUM> is a mains water supply.

Advantageously, apparatus <NUM> further comprises a light source <NUM> configured to emit ultraviolet (UV) light incident on liquid flowing from the vessel <NUM> to the fluid circuit <NUM>. Thus, liquid from the liquid source <NUM> is treated with UV rays before entering the fluid circuit <NUM>. This UV light functions to destroy bacteria present within liquid flowing from the liquid source <NUM> before it is introduced into the fluid circuit <NUM>. This ensures that a desired bacteria-free condition of the liquid within the fluid circuit <NUM> is maintained.

This feature of the apparatus <NUM> is of significant benefit when the temperature of the liquid flowing in the fluid circuit <NUM> is not high enough to kill bacteria through heat alone. For example, bacteria in liquid flowing into a fluid circuit of a heating system in which the system fluid is at a temperature of <NUM> degrees Celsius or higher can be destroyed by the heat of the existing system fluid but bacteria in liquid flowing into a fluid circuit of a cooling system in which the system fluid is at a temperature of below <NUM> degrees Celsius would not be destroyed in the same way.

According to the shown arrangement, the light source <NUM> located between the outlet valve <NUM> and the fluid circuit <NUM> and, as such, is configured to emit ultraviolet light incident on liquid flowing from the vessel <NUM> to the fluid circuit <NUM>.

However, it is to be appreciated that the light source <NUM> may be sited at any suitable location to ensure that liquid from the liquid source <NUM> is subjected to UV light emitted therefrom before entering the fluid circuit <NUM>. For example, the light source <NUM> may be located between the liquid source <NUM> and the inlet valve <NUM> and, as such, be configured to emit ultraviolet light incident on liquid flowing into the vessel <NUM> from the liquid source <NUM>. In another example, the light source <NUM> can be located to emit ultraviolet light incident on liquid within the vessel <NUM>.

The light source <NUM> may be any suitable light source. The light source <NUM> may comprise only one or more than one UV light emitting lamps, of any suitable type. The light source <NUM> may have any suitable shape and dimensions. It is to be appreciated that any physical barrier between a UV light emitting lamp of the light source <NUM> and liquid to be treated by the UV light will allow an appropriate transmission of the desired light wavelength or wavelengths therethrough. It is hence to be understood that the selection of a material or materials for defining a conduit through which liquid can travel will involve the identification of a material having suitable light transmittance properties.

As also indicated, the controller <NUM> is also in communication with the light source <NUM>, to selectively power the light source at an appropriate step or steps in a method of supplying liquid from the liquid source <NUM> to the fluid circuit <NUM>.

The controller <NUM> may be any suitable device, for example a programmable logic controller (PLC). The controller <NUM> may comprise, or otherwise have access to, a non-transitory computer-readable medium, with program instructions being stored on the non-transitory computer-readable medium that are executable by the controller to cause the controller to perform each of a plurality of functions.

A heating or a cooling system comprising a fluid circuit may comprise the apparatus <NUM>. The apparatus <NUM> may be used to provide top-up fluid to the fluid circuit of the heating or the cooling system. The apparatus <NUM> may be used to provide top-up fluid from a coldwater main supply to a fluid circuit of a heating or a cooling system.

The apparatus <NUM> may be used to maintain a desired pressurisation of a fluid circuit. It is therefore to be appreciated that other components may be present within a system comprising the apparatus <NUM>.

In an example, a method of supplying a liquid to a heating or a cooling system comprising a fluid circuit comprises the steps of, with reference to <FIG>:.

It is to be understood that at any point in time, the apparatus <NUM> may be in a non-supplying mode of operation ("air-break" mode) or in a supplying mode of operation ("filling" mode).

In an example, the mode of operation of the apparatus <NUM> is the non-supplying mode of operation ("air-break" mode) unless the supplying mode of operation ("filling" mode) is initiated.

Operations performable by the apparatus <NUM> of <FIG> will now be illustrated with reference to the method <NUM> shown in <FIG>.

During step <NUM>, an air-filled interruption ("air-break") between the liquid source <NUM> and the fluid circuit <NUM> is maintained. Both the inlet valve <NUM> and the outlet valve <NUM> are closed, and the vessel <NUM> is empty of liquid. Thus, the air in the vessel <NUM> provides a "break" in the flow path <NUM> between the liquid source <NUM> and the fluid circuit <NUM>.

At step <NUM>, a question is asked as to whether liquid is to be supplied to the fluid circuit <NUM>. If the question asked at step <NUM> is answered in the negative, step <NUM> is again entered.

However, if the question asked at step <NUM> is answered in the affirmative, step <NUM> is entered.

The entry into step <NUM> from step <NUM> represents the apparatus <NUM> switching from a non-supplying mode of operation ("air-break" mode) into a supplying mode of operation ("filling" mode).

At step <NUM>, the inlet valve <NUM> is opened. This allows liquid to flow from the liquid source <NUM> into the vessel <NUM>, which fills, during step <NUM>, because the outlet valve <NUM> is still closed. When the vessel <NUM> has filled sufficiently, step <NUM> is entered. At step <NUM>, the inlet valve <NUM> is closed and the outlet valve <NUM> is opened. This allows liquid to flow from the vessel <NUM>, which empties, during step <NUM>, because the inlet valve <NUM> is now closed. When the vessel <NUM> has drained sufficiently, step <NUM> is entered. At step <NUM>, the outlet valve <NUM> is closed. Both the inlet valve <NUM> and the outlet valve <NUM> are now closed.

At step <NUM> a question is asked as to whether more liquid is to be supplied to the fluid circuit <NUM>. If the question asked at step <NUM> is answered in the affirmative, step <NUM> is again entered.

However, if the question asked at step <NUM> is answered in the negative, step <NUM> is entered.

The entry into step <NUM> from step <NUM> represents the apparatus <NUM> switching from the supplying mode of operation ("filling" mode) back into the non-supplying mode of operation ("air-break" mode).

<FIG> shows apparatus <NUM> for supplying a liquid from a liquid source to a fluid circuit within a heating system <NUM> comprising fluid circuit <NUM>.

The direction of circulating flow of system liquid around the fluid circuit <NUM> is indicated by arrows <NUM>. Heating system <NUM> comprises a heat source <NUM>, such as a boiler, and at least one heat emitter <NUM>, such as a radiator. A main system flow pipe <NUM> extends from the heat source <NUM> to the at least one heat emitter <NUM>, and a main system return pipe <NUM> extends from the at least one heat emitter <NUM> to the heat source <NUM>.

Heating system <NUM> comprises a system pump <NUM>, which is disposed along main system flow pipe <NUM> between the heat source <NUM> and the at least one heat emitter <NUM>, and which is operable to circulate system liquid around the fluid circuit <NUM> in the direction of circulating flow <NUM>. In this illustrated example, heating system <NUM> further comprises an expansion vessel <NUM>, which is disposed along main system return pipe <NUM> between at least one heat emitter <NUM> and the heat source <NUM>.

Apparatus <NUM> is arranged to receive liquid via the fluid conduit <NUM> connected to liquid source <NUM>, in the direction of inflow <NUM>, and to supply liquid to the fluid circuit <NUM> via the fluid conduit <NUM> that is connected to the main system return pipe <NUM>, in a direction of outflow <NUM>.

The liquid supplied to the fluid circuit <NUM> of the heating system <NUM> by the apparatus <NUM> may be a flow of top-up liquid to the fluid circuit <NUM>.

It is to be appreciated that the apparatus <NUM> for supplying a liquid from a liquid source to a fluid circuit may be used within a cooling system comprising fluid circuit <NUM>.

In a specific example, apparatus for supplying a liquid to a heating or a cooling system comprising a fluid circuit comprises, with reference to <FIG>:.

In a preferred specific example, the apparatus <NUM> further comprises a light source <NUM> operable to emit ultraviolet light incident on a liquid flowing along a flow path <NUM> between the liquid source <NUM> and the fluid circuit <NUM>, the flow path <NUM> extending through the vessel <NUM>. Preferably, the light source <NUM> is operable to emit ultraviolet light incident on a liquid flowing along the flow path <NUM> at a position that is downstream of the outlet port <NUM> of the vessel <NUM>. Preferably also, the controller <NUM> is operable to selectively turn the light source <NUM> on and off, and the program instructions stored on the non-transitory computer-readable medium are executable by the controller <NUM> to cause the controller <NUM> to: maintain the light source <NUM> in an off condition during the non-supplying mode of operation, and maintain the light source <NUM> in an on condition during the supplying mode of operation.

In an example, the controller <NUM> is configured to receive an input from a sensing apparatus <NUM> for providing an indication as to the level of liquid within the vessel <NUM> and/or a timer <NUM>, which may be comprised by the controller <NUM>.

During the supplying mode, a determination that vessel <NUM> has filled to a sufficient extent may be made based on a reading output to the controller <NUM> from a sensing arrangement <NUM> for providing an indication as to the level of liquid within the vessel <NUM> and/or on a signal generated by a timer (not shown) comprised by the controller <NUM>. Similarly, a determination that vessel <NUM> has emptied to a sufficient extent may be made based on a reading output to the controller <NUM> from a sensing arrangement <NUM> for providing an indication as to the level of liquid within the vessel <NUM> and/or on a signal generated by a timer (not shown) comprised by the controller <NUM>.

Thus, in the specific example outlined above, the duration of the first period of time may be the length of time taken before a sensing arrangement <NUM> indicates that the vessel <NUM> has filled up to a predetermined extent of filling or may be a predetermined duration monitored by a timer <NUM>, this duration having previously been calculated to be adequate to allow the vessel <NUM> to fill to a suitable extent, and, likewise, the second period of time may be the length of time taken before a sensing arrangement <NUM> indicates that the vessel <NUM> has drained down to a predetermined extent of draining or may be a predetermined duration monitored by a timer <NUM>, this duration having previously been calculated to be adequate to allow the vessel <NUM> to empty to a suitable extent.

The sensing arrangement <NUM> may comprise any suitable number of sensors, the or each being of any suitable type and the or each being sited at any suitable position.

An extent of filling may be determined from a reading of the height of liquid contained within the vessel. Similarly, an extent of draining may be determined from a reading of the height of liquid contained within the vessel. Hence, in an example, the sensing arrangement <NUM> comprises a first sensor at a first position for detecting that the vessel <NUM> has filled completely or otherwise to a maximum extent, and a second sensor at a second, different position for detecting that the vessel <NUM> has emptied completely or otherwise to a minimum extent.

An extent of filling may be determined from a reading of the volume of liquid that has flowed into the vessel. Similarly, an extent of draining may be determined from a reading of the volume of liquid that has flowed out of the vessel. Hence, in an example, the sensing arrangement <NUM> comprises a first flow meter at a first position for measuring the volume of liquid flowing into the vessel <NUM> through the inlet port <NUM> and a second flow meter at a second, different position for measuring the volume of liquid flowing from the vessel <NUM> through the outlet port <NUM>.

An extent of filling may be determined from a reading of the pressure of liquid that has flowed out of the vessel. Similarly, an extent of draining may be determined from a reading of the pressure of liquid that has flowed out of the vessel. Hence, in an example, the sensing arrangement <NUM> comprises a pressure sensor at a suitable position.

In an example, the controller <NUM> is configured to receive an input from a pressure sensing arrangement <NUM> for providing an indication as to the pressure of system liquid within the fluid circuit <NUM>. The pressure sensing arrangement <NUM> may comprise any suitable number of sensors, the or each being of any suitable type and the or each being sited at any suitable position. A pressure sensor of the pressure sensing arrangement <NUM> may be located within the flow path <NUM> (as shown in <FIG>) or alternatively the fluid circuit <NUM>.

In the example of <FIG>, the apparatus <NUM> comprises the pressure sensing arrangement <NUM>. In the specific illustrated arrangement of <FIG>, the pressure sensing arrangement <NUM> is within the flow path <NUM> and, in this example, is positioned downstream of the light source <NUM>.

Initiation of the supplying mode may be made based on a reading output to the controller from a pressure sensing arrangement for providing an indication as to the pressure of system liquid within a connected fluid circuit.

Apparatus <NUM> functions to assist system liquid of a fluid circuit of a heating or a cooling system to be maintained at a desired pressure.

Steps in a method of supplying a liquid to a fluid circuit of a heating or a cooling system will now be described.

A pressure level of system liquid in the fluid circuit is measured to obtain a pressure level indication. This pressure level indication is then compared with a pressure level threshold, which is associated with a desired pressure of system liquid, to determine whether the pressure level indication is below the pressure level threshold.

In response to determining, from the comparison, that the pressure level indication is not below the pressure level threshold, the previous steps of measuring a pressure level of system liquid in the fluid circuit to obtain a pressure level indication and then comparing this pressure level indication with the pressure level threshold to determine whether the pressure level indication exceeds the pressure level threshold are repeated.

However, in response to determining, from a comparison of a pressure level indication with the pressure level threshold, that the pressure level indication is below the pressure level threshold, an activation signal is generated to initiate a supplying mode to supply liquid from the liquid source to the connected fluid circuit.

Thus, the pressure level of system liquid in the fluid circuit is measured and when a drop in the system liquid pressure is detected, the supplying mode is initiated to restore the system liquid pressure to a desired operating pressure level.

The supplying mode may be initiated if any pressure drop is detected or only if a pressure drop of a predetermined extent has been detected.

Referring to the method <NUM> of <FIG>, these pressure level measuring and comparison steps are associated with step <NUM>, at which a question is asked as to whether or not liquid is to be supplied to the fluid circuit (with step <NUM> being re-entered if the question is answered in the negative, if a pressure drop has not been detected or a predetermined extent of a pressure drop has not been detected, and with step <NUM> being entered if the question is answered in the affirmative, if a pressure drop has been detected or a predetermined extent of a pressure drop has been detected).

Further steps in the method of supplying a liquid to a fluid circuit of a heating or a cooling system will now be described.

A pressure level of system liquid is then measured to obtain a subsequent pressure level indication. This subsequent pressure level of system liquid is then compared with the pressure level threshold to determine whether the subsequent pressure level indication is below the pressure level threshold.

In response to determining, from the comparison, that the subsequent pressure level indication is not below the pressure level threshold, the previous steps of measuring a pressure level of system liquid in the fluid circuit and then comparing this pressure level indication with the pressure level threshold to determine whether the pressure level indication is below the pressure level threshold are repeated.

However, in response to determining, from a comparison of a subsequent pressure level indication with the pressure level threshold, that the subsequent pressure level indication is below the pressure level threshold, the supplying mode is again initiated.

Thus, at the end of the supplying mode, the pressure level of system liquid in the fluid circuit is measured and when the desired operating pressure level has been reached, with the system liquid topped-up properly, the non-supplying mode is entered and the pressure level of system liquid in the fluid circuit is monitored to detect a drop in the system liquid pressure; however, if the desired operating pressure level has not been reached, with further topping-up of the system liquid required, the supplying mode is again entered.

Referring to the method <NUM> of <FIG>, these further pressure level measuring and comparison steps are associated with step <NUM>, at which a question is asked as to whether or not more liquid is to be supplied to the fluid circuit (with step <NUM> being re-entered if the question is answered in the negative, if restoration to the desired operating pressure has been detected, and with step <NUM> being entered if the question is answered in the affirmative, if restoration to the desired operating pressure has not been detected).

In an example, the step of entering the supplying mode from the non-supplying mode involves the controller <NUM> switching on the light source <NUM> to begin emitting UV light and the step of entering the non-supplying mode from the supplying mode involves the controller <NUM> switching off the light source <NUM> to stop emitting UV light.

In an example, the apparatus <NUM> further comprises a pump <NUM>, which is operable to move liquid from the vessel <NUM> along the flow path <NUM> towards the fluid circuit <NUM>. The pump <NUM> may be any suitable type and sited at any suitable location.

In an example, with reference to the method <NUM> of <FIG>, the step <NUM> of allowing the vessel <NUM> to drain involves the controller <NUM> switching on the pump <NUM> to start moving liquid along the flow path <NUM> and then switching off the pump <NUM> to stop moving liquid along the flow path <NUM> at an appropriate point thereafter. Thus, the pump <NUM> is on during a period of the supplying mode and is off during the non-supplying mode.

As previously stated, according to the illustrated example, liquid flowing along the flow path <NUM> may originate from a cold mains water supply, and the UV beam incident thereon from the light source <NUM> functions to kill bacteria within this fresh water. In this way, bacteria are prevented from entering the fluid circuit <NUM> when it is being topped up.

In the specific illustrated arrangement of <FIG>, the light source <NUM> is configured to emit ultraviolet light incident on liquid flowing from the vessel <NUM> to the fluid circuit <NUM> at a position along the flow path <NUM> that is upstream of the pump <NUM>. This particular siting of the light source <NUM> serves to inhibit the flow of live bacteria into the pump <NUM>, which hinders bacterial growth on internal surfaces of the pump <NUM>. However, it is to be appreciated that the light source <NUM> may be sited at any suitable location to ensure that liquid from the vessel <NUM> is subjected to UV light emitted therefrom before entering the fluid circuit <NUM>. Thus, the light source <NUM> may be located downstream of the pump <NUM>.

Thus, in a method of supplying a liquid to a fluid circuit of a heating or a cooling system, during the supplying mode, the liquid from the liquid source is treated with UV light before entering the fluid circuit.

Optionally, and in the specific illustrated example of <FIG>, the apparatus <NUM> further comprises a dosing valve <NUM> for connection to an outlet <NUM> of an additive reservoir <NUM> such that the dosing valve <NUM> is operable to supply a flow of an additive <NUM> from the additive reservoir <NUM> to liquid flowing along the flow path <NUM>. Thus, liquid from the vessel <NUM> is dosed with an additive before entering the fluid circuit <NUM>. This ensures that a desired additive-concentration condition of the system water is maintained.

As previously stated, according to this illustrated embodiment, the liquid flowing along the flow path <NUM> may originate from a cold mains water supply, and the dosing valve <NUM> functions to dose this fresh water with the additive <NUM>. In this way, the additive <NUM> is introduced into the liquid prior to entering the system fluid when the fluid circuit <NUM> is being topped-up.

This feature of the apparatus <NUM> is of significant benefit when system fluid may be lost through leakage or maintenance draining. For example, introducing an amount of additive <NUM> as liquid enters the fluid circuit <NUM> serves to ensure that protection is provided at the earliest stage and also enables an amount of additive <NUM> to be introduced into the existing system fluid to supplement an existing concentration of the additive <NUM> therein.

The dosing valve <NUM> may be any suitable type. In an embodiment, the dosing valve <NUM> is a proportional dosage valve. The additive <NUM> may be any suitable type. In an embodiment, the additive <NUM> is a corrosion inhibitor. According to the shown arrangement, a fluid conduit <NUM>, which in this example is a flexible fluid conduit, extends from the dosing valve <NUM> into the additive <NUM>. The additive reservoir <NUM> may be any suitable type, for example a chemical container.

In the shown arrangement, the dosing valve <NUM> is located downstream of the outlet port <NUM> of the vessel <NUM>, and in this example, is downstream of the pump <NUM>. It is to be appreciated however that the dosing valve <NUM> may be sited at any suitable position for introducing the additive <NUM> to liquid flowing to the fluid circuit <NUM>.

Thus, in a method of supplying a liquid to a fluid circuit of a heating or a cooling system, during the supplying mode, an additive may be supplied to the liquid from the liquid source before entering the fluid circuit.

In an example, liquid flowing from the vessel <NUM> is treated with UV light before entering the pump <NUM> and is dosed with an additive <NUM> after exiting the pump <NUM>.

It is to be appreciated that in an embodiment in which the apparatus <NUM> comprises both the light source <NUM> and the dosing valve <NUM> that only one or the other of these features may be deployed and therefore liquid flowing from the vessel <NUM> during the supplying mode may be treated with UV light via the light source <NUM> or dosed with an additive via the dosing valve <NUM>.

Further it is to be appreciated that in an embodiment, the apparatus <NUM> comprises only one of the light source <NUM> and the dosing valve <NUM>.

Therefore, in a method of supplying a liquid to a fluid circuit of a heating or a cooling system using apparatus as described, liquid supplied to the fluid circuit may be one or both of: treated with UV light, dosed with an additive.

Further features of the specific illustrated example will now be mentioned. An isolation valve <NUM> is disposed between the liquid source <NUM> and the inlet valve <NUM>, and a pressurised isolation valve <NUM> is disposed between the outlet valve <NUM> and the fluid circuit <NUM>. A non-return valve <NUM> is disposed between the pump <NUM> and the dosing valve <NUM>, to prevent the flow of liquid back towards the pump <NUM>. In an example, air is allowed to vent from one or more positions along the fluid flow path <NUM> between the liquid source <NUM> and the fluid circuit <NUM>.

A cabinet <NUM> for housing some or all of the various components of the apparatus <NUM> is also shown. According to the illustrated embodiment, connections to componentry within the cabinet <NUM> are made via fluid conduit <NUM> (connection between liquid source <NUM> and inlet port <NUM>), fluid conduit <NUM> (connection between fluid circuit outlet port <NUM> and fluid circuit <NUM>) and fluid conduit <NUM> (connection between flow path <NUM> and additive reservoir <NUM>). The use of a cabinet <NUM> provides for convenient introduction of the apparatus <NUM> to a heating or a cooling system. The cabinet <NUM> may be any suitable shape and have any suitable dimensions, and may be fabricated from any suitable material or combination of materials.

The present invention provides apparatus for, and a method of, supplying a liquid to a fluid circuit of a heating or a cooling system. A supplying mode is initiated in response to detection of a drop in a pressure level of system liquid in the fluid circuit. A light source may be provided that is operable to treat the top-up liquid with ultraviolet light prior to entering the fluid circuit. A dosing valve may be provided that is operable to dose the top-up liquid with an additive prior to entering the fluid circuit.

Claim 1:
A method of supplying a liquid to a fluid circuit (<NUM>) of a heating or a cooling system (<NUM>), the method comprising the steps of:
(a) receiving a vessel (<NUM>) provided with an inlet port (<NUM>), through which a liquid can enter the vessel (<NUM>) in a direction of inflow (<NUM>), and an outlet port (<NUM>), through which a liquid can exit the vessel (<NUM>) in a direction of outflow (<NUM>);
(b) connecting the inlet port (<NUM>) of the vessel (<NUM>) to a liquid source (<NUM>) via an inlet valve (<NUM>), the inlet valve (<NUM>) located upstream of the inlet port (<NUM>) and operable to prevent or allow a liquid to enter the vessel (<NUM>) through the inlet port (<NUM>), and connecting the outlet port (<NUM>) of the vessel (<NUM>) to the fluid circuit (<NUM>) via an outlet valve (<NUM>), the outlet valve (<NUM>) located downstream of the outlet port (<NUM>) and operable to prevent or allow a liquid to exit the vessel (<NUM>) through the outlet port (I <NUM>), whereby a flow path (<NUM>) between the liquid source (<NUM>) and the fluid circuit (<NUM>) extends through the vessel (<NUM>);
(c) with the inlet valve (<NUM>) open and the outlet valve (<NUM>) closed, allowing liquid from the liquid source (<NUM>) to fill the vessel (<NUM>);
(d) with the inlet valve (<NUM>) closed and the outlet valve (<NUM>) open, allowing liquid within the vessel (<NUM>) to drain;
(e) with the inlet valve (<NUM>) closed and the outlet valve (<NUM>) closed, maintaining an air-filled interruption, within the vessel (<NUM>), between the liquid source (<NUM>) and the fluid circuit (<NUM>).