GB2390666A

GB2390666A - Instantaneous water heater switch

Info

Publication number: GB2390666A
Application number: GB0214536A
Authority: GB
Inventors: Dominic George Webber; Robin Craig Cocker; Peter Georg Laitenberger
Original assignee: Aqualisa Products Ltd
Current assignee: Aqualisa Products Ltd
Priority date: 2002-06-24
Filing date: 2002-06-24
Publication date: 2004-01-14
Also published as: GB2390142A; GB0214536D0; GB2390142B; GB0314020D0

Abstract

The water heater has a main valve (20, figure 2a) that is operated by a push button 22a to control the presence or absence of water to a flow rate control valve. One of two interchangeable on/off modules, 50a or 50b, may be provided to control the water flow. The on/off module 50a is a mechanical arrangement that includes a mechanical actuation member 76, a rotatable cam member 82, two springs 84 and 90, a housing 74, and attachment means 78 for the valve. The on/off module 50b is an electrical arrangement that includes an electrical actuation member such as a solenoid 52, a cantilever 56, an axially movable member 60, a housing 54, and attachment means 62 for the valve. The push button may consist of a push-push mechanism.

Description

-1 INSTANTANEOUS WATER HEATER

The present invention relates to an instantaneous water heater, in particular an instantaneous water heater for a shower whereby the on/off mechanism is simplified 5 and improved.

A great variety of different types of instantaneous water heater are known.

These may be used in conjunction with a shower such that, when a user turns on a flow of water to the shower, the water is instantaneously heated to a desired temperature. Often, temperature control is achieved by varying the water flow rate 10 through the heater can of the instantaneous water heater.

It is known to provide instantaneous water heaters with various controls for the water flow. On the one hand, a manually rotatable on/off valve may be provided together with a pressure sensitive switch for providing power to electrical heating elements when water is flowing. On the other hand, the on/offvalve and heating 15 elements can be controlled electrically with a switch on the front cover of the instantaneous water heater.

Manually rotatable control valves provide relative cheap implementation, but are less desirable to the user. In contrast, electrical/solenoid operation provides more desirable operation for the user, but is more complicated and expensive.

20 Of course, different consumers will have different priorities and, hence, it is desirable to provide both instantaneous water heaters which are relatively cheap and those which provide improved functionality. Unfortunately, to provide both the mechanical arrangement and the electrical arrangement described above in the same product range, it is necessary to provide a large number of different components, 25 thereby adding further to the overall cost.

it is an object of the present invention to overcome or at least reduce these problems. According to the present invention, there is provided a method of constructing an instantaneous water heater, the method including: 30 providing a main valve for allowing or preventing water flow through the water heater;

-2 providing an arm for controlling the main valve; providing a user operable actuator for moving said arm; providing the user operable actuator in an interchangeable on/off module; and providing interchangeable on/off modules having mechanical user operable 5 actuators and interchangeable on/off modules having electrical user operable actuators. I According to the present invention, there is also provided an instantaneous water heater for a shower including: a main valve for allowing or preventing water flow through the water heater;: 10 an arm for controlling the main valve; and i an interchangeable on/off module having a user operable actuator for moving said arson, the user operable actuator being one of a mechanical actuator and an electrical actuator and the on/off module being interchangeable with another on/off module having the other of the mechanical actuator and the electrical actuator.

15 Thus, since both the mechanical actuator and the electrical actuator move the arm in order to operate the main valve, mechanical and electrically actuated instantaneous water heaters may be provided in the same product range without the need for a large number of different components. In particular, the same main valve: may be provided irrespective of whether the system operates mechanically or 20 electrically. It is only necessary to assemble the instantaneous water heater with an appropriate one of the interchangeable on/off modules.

Preferably, the instantaneous water heater further includes a pilot valve for controlling the main valve, the arts operating the pilot valve.; In this way, only a relatively small force is required to move the arm, thereby 25 facilitating its use for both mechanical and electrical actuators. There is no need for the arm itself to directly drive the main valve so as to allow or prevent water flow.

It is well known to use pilot valves to operate main valves by opening or closing passages exposing the main valves to different pressures. Any suitable construction can be used with the present invention.

-3 Preferably, the instantaneous water heater further includes guide walls for defining a water flow path wherein the arm extends from inside to outside the guide walls. In other words, where the pilot valve opens and closes a water passage from 5 inside the water flow path, the arm extends from the pilot valve inside the water flow path to allow direct operation from outside the water flow path.

Preferably, the guide walls define a control aperture through which said arm extends, the control aperture forming a sliding seal with the arm.

Preferably, the electrical actuator has a solenoid and a cantilever, the; 10 cantilever being connected at one end to the arm and at the other end to an armature of the solenoid such that the solenoid is located remotely from the arm and is operable to move the arm so as to control the main valve.

Thus, in contrast to previous designs intended only for use with solenoid operation, the solenoid is not located directly adjacent the main valve. The valve I S includes a linkage, i.e. the arm, allowing mechanical operation or operation by the solenoid. By use of the cantilever, the solenoid can be located remotely from the valve, thereby allowing greater overall design flexibility for the instantaneous water heater. Preferably, the instantaneous water heater further includes an electrical switch 20 connected electrically to the solenoid for operating the solenoid and, hence, the main valve. The switch may be freely positioned anywhere in the front cover of the instantaneous water heater.

Preferably, the instantaneous water heater further includes a push button 25 which controls the main valve to allow and prevent water flow with consecutive pushes. The push button may include the electrical switch for the solenoid or may be a mechanical device for controlling the main valve. By providing a push-push operation such that the water heater is turned on and off by consecutive pushes of the 30 push button, it is possible to provide the user with the same feel of operation for both electrically arid mechanically actuated arrangements. This gives the mechanically

A- actuated arrangements an improved feel and desirability and reduces the overall cost! of the range by allowing greater interchangeability.

Preferably, the mechanical actuator has a push-push mechanism which moves said arm in opposite respective directions for consecutive pushes of the push button.

5 In other words, consecutive pushes result in the arm moving in one direction to control the main valve to allow water flow and in the opposite direction to control the main valve to prevent water flow.

This mechanism allows the instantaneous water heater to be provided with a greatly improved feel for the user. In particular, relatively cheap mechanical: 10 actuation is thus provided with the same push button operation as the more expensive electrical actuation.

According to the present invention, there is provided a method of constructing an instantaneous water heater for a shower, the method including: providing a main valve for allowing or preventing water flow through the I S water heater; providing an arm for controlling the main valve; providing a push button; providing a user operable actuator for moving said arm; and: constructing the user operable actuator as a mechanical actuator having a 20 push-push mechanism which is operable mechanically by said push button to move said arm in opposite respective directions for consecutive pushes of the push button.

According to the present invention, there is also provided an instantaneous water heater for a shower including:; a main valve for allowing or preventing water flow through the water heater; 25 an arm for controlling the main valve; a push button; and a user operable actuator for moving said arm; wherein the user operable actuator is a mechanical actuator having a push-push mechanism which is operated mechanically by said push button to move said arm in 30 opposite respective directions for consecutive pushes of the push button.

-5 As mentioned above, this provides a greatly improved user interface, particularly when compared to previous manual arrangements requiring manual rotation of a main valve.

Preferably, the push-push mechanism includes a rotatable cam member which 5 is stable in an even number of positions of rotation and includes a circumferential cam surface.

Preferably, the instantaneous water heater further includes a cam follower for connection to the arm, the cam follower following the cam surface such that, as the cam member is rotated between consecutive stable positions of rotation, the cam 10 follower is moved between respective linear positions.

Thus, the arm is moved so as to control the main valve as the rotatable cam member is rotated.

Consecutive positions of the rotatable cam member correspond to on and off states for the main valve such that it is sufficient for operation of the push button to 15 push the rotatable cam member from one stable position the next stable position in order to change the state of the main valve.

The rotatable cam member can be bi-stable and have two stable positions of rotation, one with the cam follower positioning the arm to control the main valve to allow water flow and the other with the cam follower positioning the arm to control 20 the main valve to prevent water now.

Preferably, the cam surface faces in a direction generally parallel to the axis of rotation of the cam member and the cam follower moves in a direction generally parallel to the axis.

For a bi-stable cam member, the cam surface thus extends from a first axial 25 position to a second axial position over 180 and then back to the first axial position over the next 180 .

Preferably, the push-push mechanism includes a spring member for biasing the cam follower towards the cam suffice.

In this way, the spring member provides the force for moving the cam 30 follower and arm in one of the two opposite directions.

- Preferably, the cam member includes a circumferential registration surface and a resilient registration member for resiliently engaging the registration surface so as to bias the cam member in opposite respective directions towards the stable positions of rotation either side of the intermediate positions.

5 In this way, it is not necessary for the user to operate the push button with any need for accuracy. The registration member ensures that the cam member is positioned accurately in either a position in which the main valve is open or a position in which the main valve is closed. Since the resilient registration member biases the cam member in opposite directions either side of the intermediate 10 positions, it is ensured that the cam member is always moved to the nearest either on or off position.

For the bi-stable mechanism, the circumferential registration surface may include an elongate member positioned on a diameter of the cam member. The resilient registration member then preferably comprises a spring member resiliently i 15 engaging on either side of the elongate member such that the cam member will always return to one of two opposite orientations with the elongate side surfaces of the elongate member engaged by the spring.

Preferably, the cam member includes engagement surfaces and the push button extends, when pushed, to engage an engagement surface and rotate the cam 20 member against the initial resisting bias of the resilient registration member until the cam member reaches the next intermediate position and the resilient registration member biases the cam member to the next stable position.

Hence, the push button is used mechanically to rotate the cam member between the required positions for opening or closing the main valve.

25 Preferably, the push button can be pushed far enough to rotate the cam i member past the next intermediate position.

This ensures that the cam member does not come to rest at an intermediate position where it is not positively biassed in either direction. The push button will rotate the cam member past the next intermediate position such that the resilient 30 registration member then ensures that the cam member is moved fully to the next i correct stable position in which the main valve is either open or closed.

-7 The invention will be more clearly understood from the following description, giving by way of example only, with reference to the accompanying

drawings, in which: Figure 1 illustrates the front cover of an instantaneous water heater according 5 to the present invention; Figures 2(a) and (b) illustrate exploded views of the functional components of instantaneous water heaters according to the present invention, Figures 3(a) and (b) illustrate the assembled water heaters of Figures 2(a) and (b); 10 Figures 4(a) and (b) illustrate the on/off module of the water heater of Figures 2(a) and 3(a); Figures 4(c) and (d) illustrate the on/off module of the water heater of Figures 2(b) and 3(b); Figure 5 illustrates the cam member of Figure 4(a); and 15 Figures 6(a) to 8(c) illustrate operation of the on/off module of Figures 4(a) and (b).

As illustrated in Figure 1, an instantaneous water heater includes a front cover 2 including a water temperature control 4 and an on/off button 6.

The front cover 2 houses a number of functional components for providing 20 hot water of a desired temperature.

Figures 2(a) and (b) illustrate suitable arrangements of components for use in such a water heater.

Water is provided to one oftwo alternative inlets 8 and 10. With the water heater running, the water is then chanrelled by a flow rate control valve 12 to the 25 inside of a heater can 14. Within the heater can 14, the water flows up around the outside of a chimney 16 in contact with a heater element 18. The water then flows down through the inside of the chirnney16 and out of an outlet 19.

A main valve 20 operates under the control of a button 22a, 22b to control whether or not there is any flow from the inlets 8 or 10 to the flow rate control valve 30 12. Dependant upon the position of the main valve 20 and/or flow of water through

-8 the water heater, a rod 24 operates an electrical switch 26 to turn on or off power to the heater element 18.

The flow rate control valve 12 may be operated by a rotatable member 28 so as to vary the flow rate through the heater can 14 and, hence, the outlet temperature.

5 Figures 2(a) and (b) and also Figures 3(a) and (b) are illustrated with alternative on/off modules 50a and 50b which are provided interchangeably with the rest of the apparatus.

The on/off module 50a of Figures 2(a) and 3(a) provides mechanical actuation of the main valve 20 and will be described further below. On the other 10 hand, the on/off module 50b of Figures 2(b) and 3(b) provides electrical actuation of the main valve 20 by means of a solenoid 52.

Figures 4(c) and (d) illustrate components of the on/off module 50b.

The solenoid 52 is mounted to a module housing 54 which may be interchangeably mounted to the rest of the components illustrated in Figures 2(a) and 15 (b). Within the housing 54 is provided a cantilever 56 which is supported by a pivot 58. The housing 54 also supports an axially movable actuation member 60 including a connection 62 for engaging a part of the valve assembly so as to control the main valve 20. Once engaged, the member 60 can be considered as part of an arm for controlling the main valve 20.

20 The member 60 is provided with a peripheral flange 64 which is engaged by a slot 66 in one end of the counter leaver 56. The other end of the counter leaver 56 as illustrated includes a pivot opening 68 for receiving an extension to the armature 70 of the solenoid 52.

In use, actuation of the solenoid 52 will cause the armature 70 to pivot the 25 counter leaver 56 and hence move the member 60 along its axis. As mentioned above, the member 60 is attached to the valve assembly. With the member 60 in one axial position, the main valve 20 is opened and with the member 60 in another opposite axial position, the main valve 20 is closed. Thus, by using the solenoid 52 to move the member between its two axial positions, the main valve 20 may be 30 opened and closed.

-9- As mentioned above, the on/off module 50b is interchangeable with the on/off module 50a employing mechanical actuation.

As illustrated in Figures 4(a) and (b), the housing 74 of the on/off module 50a has the same general form for mating with the rest of the components of the 5 instantaneous water heater. Indeed, it is provided with an actuation member 76 which is axially and slidably supported in the housing 74 in the same relative position as the member 60 in the housing 54. It also includes similar means 78 for attachment to valve components. Thus, the on/off module 50a may be interchangeably assembled in the instantaneous water heater with the on/off module 10 50b. Operation ofthe push button 22a will operate the member 76 in the same manner as actuation of the solenoid 52 will operate member 60.

Operation of the mechanism of on/off module 50a will be described in further detail below. However, referring to Figure 4(a), it will be seen that the push button 22a includes an extension 80 which engages with a rotatable cam member 82.

15 Against the resistance of a spring 84, the push button 22a may be pushed such that the extension portion 80 rotates the cam member 82 by a predetermined angle.

As illustrated, the rotatable cam member 82 is provided with a downwardly facing cam surface 86 and the member 76 is provided with a cam follower 88.

A spring 90 is also provided to ensure that the cam follower 88 engages the 20 cam surface 86.

Thus, as the rotatable cam member 82 rotates, due to the varying axial position of the surface 86, the member 76 is moved axially so as to control the main valve 20.

As will be described further below, the illustrated cam member 82 is bistable 25 and has an elongate section across its diameter towards the upper surface. A resilient registration member 92 such as a spring engages the surfaces of the cam member 82 to ensure that the cam member 82 is always biassed to either of two opposite orientations. These orientations correspond to positions of the member 76 for the main valve 20 to be open or closed.

30 Figures S(a) and (b) illustrate in greater detail the cam member 82.

-10 The cam member 82 includes a central region 92 on which the cam surface 86 is formed. The cam member 82 is rotatable about a central axis 94 and the cam surface 86 is formed around a circumference of the central region 92. The cam surface 86 faces in an axial direction, i.e. downwardly as illustrated. Around the 5 circumference, the cam surface varies in an axial location such that, with ret'erence to Figure 4(a) the cam follower 88 and member 76 are moved axially to and fro.

The illustrated embodiment is bi-stable such that the cam member 82 is resiliently biassed to come to rest in two rotational positions. Corresponding to these positions, the cam surface 86 extends between two axial locations, such that in one 10 rotational position of the cam member 82, the cam follower 88 is at one axial position and at the other rotational position of the cam member 82, the cam follower 88 is at the other axial position. To achieve this, the cam surface 86 may have a generally planar surface which is slanted with respect to the axis 94.

Above the central region 92 is a registration region 96 including a registration 15 surface 98 and above the registration region 96 is an engagement region l GO with an engagement surface 102.

With reference to Figure 4(a), the extension 80 of the button 22a is intended to engage with the engagement surface 102 of the engagement region lOO. In particular, it engages at a position off set from the axis 94 so as to rotate the cam 20 member 82 upon depression of the button 22a. In the preferred embodiment, it is intended that the button 22a will only require 6mrn of movement to rotate the cam member 82 to its next stable position. As will be described below, this is achieved with the resilient registration spring 92 which acts on the registration surface 98 of the registration region 96 so as to bias the cam member 82 to its next stable positions.

25 The operation of the cam member 82 is illustrated schematically in Figures 6(a) to (c), 7(a) to (c) and 8(a) to (c).

In the state illustrated in Figure 6(a), 7(a) and 8(a), the cam follower 88 and member 76 extend axially furthest towards the valve components. In other words, the cam surface is positioned axially towards the valve components and the central 30 region 92 is at its thinnest.

-11' Figure 6(a) illustrates the engagement region 100 at the top of the cam member 82. As illustrated, depressing button 22a causes the extension 80 to engage the engagement region 100 and to rotate the cam member 82 to the position as illustrated in Figure 6(b).

5 Figure 7(a) illustrates schematically the registration region 96 below the engagement region 100. As illustrated, the resilient spring 92 contacts either side of; the registration region 96. As the cam member 82 is rotated, the registration region 96 separates the arms of the spring 92. Thus, rotation of the cam member 82 is against the resilient force of the spring 92.

10 At this point, the cam surface 86 and cam follower 88 are at an intermediate position. It will be seen that there is an intermediate position beyond which the spring 92 acts on the registration surface 98 of the registration region to rotate the cam member 82 to the next rotational stable position. Hence, without any further 15 depression of button 22a, the spring 92 acts to rotate the cam member 82 to the next stable position as illustrated in Figures 6(c), 7(c) and 8(c).

At this position, as illustrated in Figure 8(c), the cam follower 88 and member 76 are axially located further away from the valve components.

The two rotationally stable positions and the two corresponding axial 20 positions for the cam follower 88 and member 76 correspond respectively to the main valve being opened and closed. Hence, with consecutive pushes of the button 22a, the cam member 82 is rotated between its rotationally stable positions and the main; valve is opened and closed.

It is sufficient for the button 22a and extension 80 to move far enough to 25 rotate the cam member by more than 90 . Once this angle has been exceeded, the spring 92 ensures that the cam member 82 is moved through the full 180 .

In this preferred embodiment, the cam member has stable positions at 1 X0 intervals. This allows plenty of movement of the components and reduces the need for accurate tolerances. However, the cam member 82 could be provided with any 30 even number of stable positions allowing the cam follower 88 and member 76 to move consecutively between their two axial positions. Of course, the cam surface 86

-12 would also extend axially in opposite directions a corresponding number of times around the circumference. In that case, an appropriate arrangement of engagement surfaces (for instance more like teeth) would be required and the registration region would have to be designed accordingly (for instance having a generally square, 5 hexagonal, octagonal etc. cross section).

Claims

-13 CLAIMS

1. An instantaneous water heater for a shower including: a main valve for allowing or preventing water flow through the water heater; 5 an arm for controlling the main valve; and an interchangeable on/off module having a user operable actuator for moving said arm, the user operable actuator being one of a mechanical actuator and an electrical actuator and the on/off module being interchangeable with another on/off module having the other of the mechanical actuator and the electrical actuator.

l 0 2. An instantaneous water heater according to claim l wherein the electrical actuator has a solenoid and a cantilever, the cantilever being connected at one end to said arm and at the other end to an armature of the solenoid such that the solenoid is located remotely from said arm and is operable to move said arm so as to control the main valve.

l 5 3. An instantaneous water heater according to claim 2 further including an electrical switch connected electrically to said solenoid for operating said solenoid and, hence, said main valve.

4. An instantaneous water heater according to claim l, 2 or 3 further including: 20 a push button which controls the main valve to allow and prevent water flow with consecutive pushes.

5. An instantaneous water heater according to claim 4 wherein the mechanical actuator has a push-push mechanism which moves said arm in opposite respective directions for consecutive pushes of the push button.

25 6. An instantaneous water heater for a shower including: a main valve for allowing or preventing water flow through the water heater; an arm for controlling the main valve; a push button; and a user operable actuator for moving said arm; wherein

-14 the user operable actuator is a mechanical actuator having a pushpush mechanism which is operated mechanically by said push button to move said arm in opposite respective directions for consecutive pushes of the push button.

7. An instantaneous water heater according to claim 5 or 6 wherein the 5 push-push mechanism includes: a rotatable cam member which is stable in an even number of positions of rotation and includes a circumferential cam surface.

8. An instantaneous water heater according to claim 7 further including: a cam follower for connection to said arm, the cam follower following said l O cam surface such that as said cam member is rotated between consecutive stable positions of rotation said cam follower is moved between respective linear positions.

9. An instantaneous water heater according to claim 7 or 8 wherein the rotatable cam member is bistable and has two stable positions of rotation, one with the cam follower positioning the arm to control the main valve to allow water flow 15 and the other with the cam follower positioning the arm to control the main valve to i prevent water flow.

10. An instantaneous water heater according to claim 8 or 9 wherein the cam surface faces in a direction generally parallel to the axis of rotation of the cam member and the cam follower moves in a direction generally parallel to the axis.

20 11. An instantaneous water heater according to claim 9 or lO wherein the push-push mechanism includes a spring member for biasing the cam follower towards the cam surface.

12. An instantaneous water heater according to any one of claims 7 to l l i wherein the cam member includes a circumferential registration surface and a 25 resilient registration member for resiliently engaging said registration surface so as bias the cam member in opposite respective directions towards the stable positions of rotation either side of intermediate positions. I 13. An instantaneous water heater according to claim 12 wherein the cam member includes engagement surfaces and the push button extends, when pushed, to 30 engage an engagement surface and rotate the cam member against the initial resisting bias of the resilient registration member until the cam member reaches the next

interrnediate position and the resilient registration member biases the cam member to the next stable position.

14. An instantaneous water heater according to claim 13 wherein the push button can be pushed fir enough to rotate the cam member past the next intermediate S position.

l S. An instantaneous water heater according to any preceding claim further including: a pilot valve for controlling the main valve, said arm operating said pilot valve. 10 16. An instantaneous water heater according to any preceding claim further including: guide walls for defining a water flow path; wherein the arm extends from inside to outside the guide walls.

l 7. An instantaneous water heater according to claim 16 wherein the I S guide walls define a control aperture through which said arm extends, the control aperture forming a sliding seal with said arm.

18. A method of constructing an instantaneous water heater, the method including: providing a main valve for allowing or preventing water flow through the 20 water heater; providing an arm for controlling the main valve; providing a user operable actuator for moving said arm; providing the user operable actuator in an interchangeable on/off module; and providing interchangeable on/off modules having mechanical user operable 25 actuators and interchangeable on/off modules having electrical user operable actuators. l9. A method of constructing an instantaneous water heater for a shower, the method including: providing a main valve for allowing or preventing water flow through the 30 water heater; providing an arm for controlling the main valve;

-16- 1

providing a push button; providing a user operable actuator for moving said arm; and I constructing the user operable actuator as a mechanical actuator having a push-push mechanism which is operable mechanically by said push button to move 5 said arm in opposite respective directions for consecutive pushes of the push button.

20. An instantaneous water heater constructed and arranged substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings. 21. A method of constructing an instantaneous water heater substantially 10 as hereinbefore described with reference to and as illustrated by the accompanying drawings.