GB2522464A

GB2522464A - A thermostatic flow valve for use in water heating systems

Info

Publication number: GB2522464A
Application number: GB1401274.4A
Authority: GB
Inventors: Justin Mcinerney
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-01-27
Filing date: 2014-01-27
Publication date: 2015-07-29
Also published as: GB201401274D0

Abstract

The valve 1 has a valve body 2 having a water inlet 3, water outlet 4 and a thermostatic valve assembly. The assembly has a thermostatic actuator 7, valve member 8 and spring 9 that biases the valve member into a closed position (figure 2). The thermostatic actuator displaces the valve member against the bias of the spring as a temperature of water in the valve increases, preferably away from an annular sealing end 16 so as to move the valve member into an open position (figure 3). The valve member includes a pressure responsive flow regulator 10 that permits a reduced flow of water through the valve when the valve member is in the closed position. The regulator comprises an aperture and an elastomeric member cooperating therewith that changes in shape with water pressure to change the size of the aperture. A water heater, such as a boiler, having a thermostatic valve and a pressure responsive flow regulator provided on an outlet of the boiler is also claimed. The regulator ensures a constant, minimum flow rate of water through the boiler to ensure boiler activation. The thermostatic valve ensures water leaving the boiler is heated to a desired temperature.

Description

A thermostatic flow valve suitable for use in water heating systems

Introduction

The invention relates to a thermostatic flow valve, especially a thermostatic flow valve for combination boiler heating systems.

With combination boiler water heating systems, the boiler is actuated when a hot tap is turned on.

However, during the time that the boiler heats up, a large volume of cold or lukewarm water will have passed through the boiler and out of the hot tap. When the water is being supplied to a sink or a bath, this water will be allowed to drain resulting in considerable water wastage. It is estimated that the average household wastes between 1500 and 2000L of water annually in this way. Additionally, as the water is passing through the boiler at a normal operating flow rate during the heating phase, it will take longer to heat the water.

Thermostatic flow valves have been provided to address this problem, and one such valve is described in W02010/082054. This valve comprises a valve body having a fluid inlet and a fluid outlet and a thermostatic valve assembly located within the flow path connecting the fluid inlet to the fluid outlet.

The thermostatic valve assembly comprises an actuator member, a valve member, and biasing means for biasing the valve member into a closed position, wherein the actuator member cooperates with the valve member and displaces the valve member as the temperature of the fluid in the flow path increases. The valve member also includes a trickle valve which allows a minimum flow of water when the valve member is in the closed position (i.e. before the water temperature has reached a threshold temperature), generally 2-2.5L/min, whereupon when the water temperature reaches a pre-defined temperature, the actuator displaces the valve member allowing a full flow of hot water through the valve.

A problem of devices of this type of thermostatic valve is that most domestic and industrial water supplies operating under variable pressure, depending on the location of the house and the time of the year. Thus, the water supply to one house may be 2 Bar and that to another house may be 3 Bar.

Likewise the water supply pressure to a house in January may be 2.5 Bar and in July may be 2 Bar.

Changes in pressure in water supply result in changes in the waterflow pressure in the heating system.

This requires that thermostatic valves of the above-described type to be calibrated during installation, to ensure that the flow rate of the thermostatic valve when in the closed position is sufficient to actuate the boiler (i.e. 2.SLJmin). To address this problem) valves of the above-described type include a calibration mechanism comprising an adjustable by-pass flow channel that can be adjusted during installation to set the required minimum flow rate atthe water supply pressure. However, even when correctly installed) if the water supply pressure subsequently drops) then the flow rate through the thermostatic valve when in the closed position will also drop, in some cases resulting in an insufficient flow rate to actuate the boiler.

It is an object of the invention to overcome at least one of the above-referenced problems. In particular, it is an object of the invention to provide a thermostatic valve that does not require calibration during installation, and which will operate normally over a range of water supply pressures.

Statements of Invention

The Applicant has discovered that problems of the above-referenced type can be obviated by incorporating into the valve member a pressure-responsive flow regulator of the type comprising an aperture for flow of water, and an elastomeric member co-operating with the aperture that is capable of changing shape in response to water pressure changes to change the size of the aperture. With a flow regulator of this type) the flow of the water through the flow regulator will remain constant irrespective of changes in pressure in the water supply. The Applicant has shown that at a flow rate of 2.2L/min of water at 42CC, the flow rate remains substantially constant over a range of water supply pressures from 1 to 3 Bar.

Thus, in a first aspect of the invention, there is provided a thermostatic valve according to the preamble of Claim 1, characterised in that the valve member comprises a pressure responsive (or pressure stabilised) flow regulator adapted to allow a reduced flow of fluid through the valve when the valve member is in the closed position, wherein the pressure responsive flow regulator comprises an aperture for flow of water) and an elastomeric member cooperating with the aperture that is capable of changing shape in response to water pressure changes to change the size of the aperture.

In this specification) the term "pressure responsive.-flow regulator" or "pressure stabilised flow regulator" should be understood to mean a valve of the type having an aperture defining a flow path for fluid) and an elastomeric member cooperating with the aperture that is capable of changing shape in response to water pressure changes to change the shape of the aperture and thereby modulate the flow rate of fluid through the aperture. Pressure responsive flow regulators of this type are sold by the company NEOPERL, and generally comprise a cylindrical housing, and insert in the housing defining an annular aperture for flow of fluid) and an elastomeric ring disposed within or adjacent to the annular aperture and in the flow of fluid, that changes shape in response to changes in the pressure of the fluid thereby changing the size of the aperture. Thus, in the context of the present invention) when the pressure of the water increases) the elastomeric ring will be compressed and flatten somewhat, to narrow the aperture through which fluid can flow) resulting in any increases in the flow rate through the aperture due to the pressure increased being negated by the decrease in size of the aperture.

Preferably) the valve member comprises a through bore closed by the flow regulator. Suitably) a distal end of the valve member comprises a guide path for receipt of the actuator member, and a proximal end of the valve member suitably comprises a seat for receipt of the flow regulator.

In one embodiment, the valve body comprises a first part having a seat for the actuator and an annular valve headset that in use forms a sealing engagement with the valve member) and a second part adapted to engage with the first part, and wherein the biasing means is disposed between the valve member and the second part such that engagement between the first and second parts biases the valve member into a sealing engagement with the valve headset. Suitably, a sealing end of the valve member is annular and the valve headset is annular.

Suitably, the biasing means comprises a spring, ideally a helical spring. Typically, the helical spring embraces the valve member and extends proximally of the valve member. Preferably, the second part of the valve body comprises a guide tube dimensioned for receipt of the helical spring, and a shoulder that abuts a proximal end of the helical spring.

In another aspect, the invention relates to a water heating system comprising a heater for water, a hot water outlet pipe, and a valve according to the invention installed in the hot water outlet pipe.

Suitably, the water heater is a combination boiler or a shower heater. However) the valve of the invention may be employed with other types of boilers or water heaters.

In another aspect, the invention provides a water heater such as a combination boiler or a shower heater comprising a valve of the invention integrally formed with the water heater. In this embodiment, the valve is supplied as an integral part of the boiler or water heater and does not need to be fitted to the water system separately to fitting the boiler or water heater. The valve of the invention is generally fitted to the hot outlet of the boiler or water heater.

In another aspect of the invention) the invention provides a water heater such as a combination boiler or a shower heater having water heating means and a hot water outlet, the hot water outlet comprising (a) a thermostatic valve of the type comprising a valve body having a fluid inlet and a fluid outlet and a thermostatic valve assembly located within the flow path connecting the fluid inlet to the fluid outlet, the thermostatic valve assembly comprising an actuator member, a valve member, and biasing means for biasing the valve member into a closed position, wherein the actuator member cooperates with the valve member and displaces the valve member as the temperature of the fluid in the flow path increases, and (b) a pressure responsive flow regulator provided in the hot water outlet proximate of the thermostatic valve and adapted to allow a reduced flow of fluid through the valve when the valve member is in the closed position. In this aspect of the invention, the thermostatic valve and flow regulator do not form part of a unitary valve, but may be fitted to as separate parts to the hot outlet, with the flow regulator being fitted upstream of the thermostatic valve.

Brief Description of the Figures

The invention will be more clearly understood from the following description of some embodiments thereof given by way of example only with reference to the accompanying figures in which: Fig. 1 is an exploded view of the thermostatic valve of the invention; Fig. 2 is a sectional view of the thermostatic valve of Fig. 1 in a closed position; Fig. 3 is sectional view of the thermostatic valve of Fig. 1 in an open position; Fig. 4 is an illustration of a water heating including a thermostatic valve of the invention; and Fig. 5 is an illustration of a water heater according to the invention.

Detailed Description of the Invention

Referring to the figures, there is illustrated a thermostatic valve of the invention indicated generally by the reference numeral 1 and comprising a valve body 2 having a fluid inlet 3 and a fluid outlet 4 and a thermostatic valve assembly 5 located within the flow path 6 connecting the fluid inlet 3 to the fluid outlet 4. The thermostatic valve assembly 5 comprising a thermostatic actuator member 7, a valve member 8, and biasing means, in this case a helical spring 9, for biasing the valve memberS into a closed position shown in Fig. 2. The thermostatic actuator member 7 cooperates with the valve member S and can displaces the valve member when the temperature of the fluid in the flow path increases to a pre-set temperature which is generally 42-43T. The valve member) which is this embodiment is essentially cylindrical, comprises a pressure responsive flow regulator 10 adapted to allow a reduced flow of fluid through the valve member when it is in the closed position (see flow lines A of Fig. 2).

The pressure responsive flow regulator (not illustrated) comprises a cylindrical fitting having an elastomeric ring at least partly defining an annular passage in the fitting and configured to expand upon increase in pressure in the incoming fluid. Thus, as the pressure in the incoming water increases, the elastomeric ring expands to increase the size of the annular aperture, thereby reducing the pressure in the water. A suitable pressure responsive flow regulator is a NEOF'ERL flow regulator that is designed to allow a flow rate of 2.2L/min irrespective of changes in pressure in the water supply over a range of 1-3 Bar.

In more detail, a proximal end 11 of the valve member 8 comprises a seat (not shown) for receipt of the flow regulator 10. A distal end 12 of the valve member comprises a guide tube 13 for receipt of a leading end 15 of the thermostatic actuator member 7, and an annular sealing end 16. The helical spring 9 is dimensioned to embrace the valve memberS in a tight manner, with a proximal end 17 of the spring 9 extending axially beyond the proximal end 11 of the valve member.

The thermostatic actuator member 7 comprises a flange 20 intermediate its ends. In use, the actuator is disposed within the flow path of the fluid and is configured to expand longtitudinally in response to an increase in the fluid temperature above 42CC.

In more detail, the valve body 2 comprises a generally cylindrical first part 23 having an annular seat 24 dimensioned to support the flange 20 of the actuator member, and an annular valve headset 25 that in use forms a sealing engagement with the sealing end 16 of the valve member 8, and a generally cylindrical second part 27 adapted to engage with the first part 23 to enclose the thermostatic valve assembly 5. The first and second parts 23, 27 are threaded for engagement, although other engagement means may be employed. When the first and second parts of the valve body engage together, the helical spring 9 is compressed between the two parts thereby forcing the sealing end 16 of the valve member 8 into a sealing engagement with the annular valve headset 25, thereby closing the flow path through the valve. In this position, the only fluid that is allowed to flow through the valve is through the flow regulator 10 (see flow lines A).

Referring to Fig. 4, there is illustrated a combination domestic water boiler indicated generally by the reference numeral 30 and having a cold water inlet 31', a water boiler 32, water outlet 33 and an electric shower appliance 34. A thermostatic valve of the invention 1 is installed in the water outlet line 33. In use, when the boiler 32 is off, the thermostatic valve assembly is biased by the helical spring into the closed position (Fig. 2) in which the sealing end 16 of the valve member is forced against the valve headset 25 (closed position). In this closed position, the only fluid that passes through the valve is through the flow regulator (see flow lines A), which is set to a fluid flow-rate of 2.2L/min. When the shower appliance 34 in the system is turned on, water flows through the flow regulator, thereby actuating the boiler to begin heating the water. As the temperature of the water rises, the valve remains in the closed position (Fig. 2) limiting the flow of water to about 2.2L/min, until the temperature of the water reaches 43°C. At this point, the thermostatic actuator member 7 expands, pushing the valve member 8 against the spring bias and displacing the sealing end of the valve member 16 from the valve headset 25 (see Fig. 3)). In this position, the water can flow along flow lines A and B, and the flow rate of the hot water consequently increases to 6-11 L/min.

The flow regulator 10 ensures that any fluctuations in water pressure do not affect the correct operation of the system by keeping the water flow rate constant when pressure fluctuations occur.

Thus, even if the water pressure in the supply line falls, the flow rate of water in the system will be maintained and thus will still actuate the boiler when a tap is turned on. Without the flow regulator in place, for example if the valve simply employs a trickle valve of the devices of the prior art, when the pressure in the supply line falls, the flow rate in the valve may fall below the minimum flow rate required to actuate the boiler. In this situation, the valve would need to be re-calibrated to take into account the fluctuations in the pressure line.

In another embodiment, and referring to Fig. 5, the invention provides a combination boiler 40 that incorporates a thermostatic valve 41 and a separate flow regulator 42. In this embodiment, both the thermostatic valve and the flow regulator are installed in the hot outlet line 43 with the flow regulator 42 being installed upstream of the thermostatic valve 41. In this embodiment, the thermostatic valve is essentially the same as the valve of the invention with the exception that the valve member does not include a flow regulator, but rather includes a trickle valve such as the arrangement disclosed in W02010/082054. The flow regulator is the same as that employed in the embodiment described above, and may be mounted in a suitable housing that is installed in the hot outlet line upstream of the thermostatic valve.

Experimental The valve of the invention was tested to determine the changes in flow rate occurring with changes in pressure in water supply. The valve was connected to a supply of water at 42CC along with an adjustable pump and the flow rate through the valve was measured water pressures of 1.0, 1.5, 2.0.

2.5, and 3.0 Bar (which is a typical range of pressures that would be experienced during fluctuations in a domestic water supply). Over this range of water pressures, the flow rate of the water was found to remain between 2.3 to 2.6 L/min, which is a sufficient flow rate to actuate combination boilers. The experiment was repeated with water at 45°C, at which temperature the flow rate was found to increase from 6L/min to ilL/mm as the pressure of the water supply increased from 1.0 Bar to 3.0 Bar.

The invention is not limited to the embodiment hereinbefore described which may be varied in construction and detail without departing from the spirit of the invention.

Claims

Claims A valve (1) comprising a valve body (2) having a fluid inlet (3) and a fluid outlet (4) and a thermostatic valve assembly (5) located within a flow path connecting the fluid inlet to the fluid outlet, the thermostatic valve assembly (5) comprising a thermostatic actuator member (7), a valve member (8), and biasing means (9) for biasing the valve member into a closed position, wherein the thermostatic actuator member (7) cooperates with the valve member (8) and displaces the valve member as the temperature of the fluid in the flow path increases, characterised in that the valve member comprises a pressure responsive flow regulator (10) adapted to allow a reduced flow of fluid through the valve when the valve member is in the closed position, wherein the pressure responsive flow regulator comprises an aperture for flow of water, and an elastomeric member cooperating with the aperture that is capable of changing shape in response to water pressure changes to change the size of the aperture.
2. A valve as claimed in Claim 1 in which the valve member comprises a through-bore defining a flow path for the fluid, and in which the pressure responsive flow regulator is disposed within the through-bore.
3. A valve as claimed in Claim 1 or 2 in which the aperture and elastomeric flow member are annular.
4. A valve as claimed in any preceding Claim in which a distal end (12) of the valve member (8) is configured to receive the thermostatic actuator member (7) and a proximal end (11) of the valve member (8) comprises a seat for the pressure responsive flow regulator (10).
5. A valve as claimed in any preceding Claim in which the valve body (2) comprises a first part (23) having a seat (24) for the thermostatic actuator member (7) and an annular valve headset (25) dimensioned to form a sealing engagement with an annular sealing end (16) of the valve member, and a second part (27) adapted to engage with the first part (23), and wherein the biasing means (9) is disposed between the valve member (8) and the second part (27) such that engagement between the first and second parts biases the sealing end (16) valve member into a sealing engagement with the valve headset (27).
6. A valve as claimed in Claim 6 in which the biasing means is a helical screw means (9) that embraces and extends proximally of the valve member (8).
7. A water heating system comprising a heater for water) a hot water outlet pipe) and a valve according to of Claims ito 7 installed in the hot water outlet pipe.
8. A water heating system as claimed in Claim 8 in which the water heater is a combination boiler or a shower heater.
9. A water heater such as a combination boiler or a shower heater comprising a valve of any of Claims 1 to 7 integrally formed with the water heater.
10. A water heater such as a combination boiler or a shower heater having water heating means and a hot water outlet, the hot water outlet comprising (a) a thermostatic valve of the type comprising a valve body having a fluid inlet and a fluid outlet and a thermostatic valve assembly located within the flow path connecting the fluid inlet to the fluid outlet, the thermostatic valve assembly comprising an actuator member, a valve member, and biasing means for biasing the valve member into a closed position, wherein the actuator member cooperates with the valve member and displaces the valve member as the temperature of the fluid in the flow path increases, and (b) a pressure responsive flow regulator provided in the hot water outlet proximate of the thermostatic valve and adapted to allow a reduced flow of fluid through the valve when the valve member is in the closed position.