GB2052699A

GB2052699A - Water or the Like Electric Heater

Info

Publication number: GB2052699A
Application number: GB8012432A
Authority: GB
Original assignee: KOZYHEAT Ltd
Current assignee: KOZYHEAT Ltd
Priority date: 1979-04-17
Filing date: 1980-04-15
Publication date: 1981-01-28
Also published as: ZM4280A1; AU5754880A; IL59790A0; ZW8780A1; MW1880A1; DE3014181A1

Abstract

A heater has a solid housing 12 with an inlet 14 and an outlet 18. At least one heating passage 22 and a switch passage 24 is formed in the housing 12 between the inlet 14 and outlet 18. The heating passage 22 contains an electrical heater element 26.1, 26.2 in direct contact with the fluid to be heated. The switch passage 24 contains a switch 38, 40 at least partially in the fluid flow path through the switch passage 24 and controls current flow to the heater element 26.1, 26.2. The switch 38, 40 is responsive to variations in fluid flow and/or to predetermined variations in temperature of the fluid. <IMAGE>

Description

SPECIFICATION Heater This invention relates to a heater particularly, althouth not necessarily exclusively, intended for heating water. The heater can be typically used for showers, wash hand basins, kitchen sinks, and the like, in homes, hotels, and the like.

According to the invention, there is provided a heater which includes a solid housing having an inlet and an outlet for fluid to be heated, the housing having formed therein at least one heating passage and a switch passage intermediate the inlet and the outlet, the heating passage containing an electrical heater element which, in use, is in direct contact with the fluid to be heated and which is connectable to an electrical power source, and the switch passage containing a switch at least partially in the fluid flow path through the switch passage and being adapted to control the supply of current to the heater element, the switch being responsive to variations in fluid flow and/or to predetermined variations in temperature of the fluid.

The housing may have a plurality of heater elements therein, connected in series or parallel.

Each heater element may, if desired, be separately energisable via suitable switch means.

The passages in the housing may be formed by drilling and closed off by suitable plugs, or may be formed by a moulding or casting operation.

The switch passage may be in communication with the heating passages or passages via an intermediate passage. The intermediate passage may be in close proximity to the outlet of the housing if the switch passage is downstream of the heating passage or close to the inlet if the switch passage is upstream of the heating passage. The fluid flow path through the switch passage is accordingly relatively short but sufficient to permit fluid to impinge on portion of the switch when the switch is responsive to variations in fluid flow. When the switch is additionally or alternatively responsive to variations in temperature, portion of the switch in use may be immersed in the fluid passing through the housing. Also, when the switch is responsive to variations in temperature, it and the switch passage must be located downstream and not upstream of the heating passage.Conveniently, an air pocket is formed in the switch passage' above the fluid flow path from the intermediate passage to the inlet or outlet so that contacts of the switch operate in such a pocket.

The switch may comprise a fixed contact and a movable contact which is provided at one end of an arm. The arm may be pivoted intermediate its ends with its other end in the fluid flow path. Said other end of the arm may be in the form of a bimetal strip when the switch is responsive to variations in temperature. The arm may additionally or alternatively have a vane in the fluid flow path for assisting movement of the arm when the switch is responsive to variations in fluid flow.

The fixed contact may be adjustable to permit adjustment of the sensitivity of the switch. When a bi-metal strip is used, an adjustable anchor may also be provided against which the bi-metal strip, in use, can abut to operate the switch.

The housing may be of a synthetic plastics material or any other electrically insulative material.

Further according to the invention, there is provided a regulating valve adapted for use in conjunction with the heater, the valve including a valve body having an outlet connectable to the inlet of the heater, the body defining a socket at its inlet end and containing a removable spigot, the' spigot serving to locate a resiliently flexible washer fitted in the inner end of the socket, the spigot protruding from the socket and being adapted for connection to a fluid source and the spigot having locating means for locating it on a support, the resilient washer having a central aperture which, in use, as the washer is resiliently deformed by increase of pressure of fluid, restricts the degree of fluid flow through the valve.

The valve is conveniently such that the maximum rate of fluid flow therethrough is substantially constant over a relatively wide range of pressures from the fluid source.

The outlet of the valve may be in the form of a further spigot integrally formed with the valve body.

The spigot may be screw-threaded into the socket.

The locating means may include a threaded nut provided on the spigot.

The invention extends further to a heating unit including a heater as above described in combination with a regulating valve as above described.

The valve body may, if desired, be integrally formed with the housing of the heater.

The heater and valve may be mounted in a cabinet having mounting means for mounting it on a surface.

The heater and valve may be mounted on a back panel of the cabinet or in a box, and be enclosed by a door or cover.

The cabinet may also house electrical circuitry responsive to the switch of the heater and adapted to control the energisation of the heater element.

Indicator means may also be provided for indicating when the heater element is energised.

The circuitry may be of the fail-safe type so that in the event of a failure, the heater element is automatically de-energised.

An embodiment of the invention is now described by way of example with reference to the accompanying drawings, in which Figure 1 shows a sectional view through a heater in accordance with the invention; Figure 2 shows an axial section through a regulating valve in accordance with the invention and also shows how the regulating valve is mounted in a cabinet; Figure 3 shows an axial section of the regulating valve of Figure 2 by itself and under high inlet pressures; Figure 4 shows a three-dimensional view of a cabinet for a heater unit in accordance with the invention; Figure 5 shows a front elevation of the cabinet of Figure 4; and Figure 6 shows a schematic circuit diagram of the electrical circuitry used in the heater unit.

Referring to Figure 1, reference numeral 10 generally indicates a heater which includes a solid housing 12 made of polymethyl-methacrylate or other similar electrically insulative material. The housing 12 has an inlet 14 to which water is supplied via piping 16, and an outlet 1 8 connected to piping 20 through which heated water is supplied to a shower, basin, sink, or the like.

In this embodiment, two heating passages 22 and a single switch passage 24 are formed in the housing 12 by drilling.

The heating passages 22 each contain an electrical heater element 26.1 and 26.2. The heater elements are in the form of a coil and extend along the inner wells of the passages 22 so that, in use, they are in direct contact with the water flowing through the passages 22. The heater elements 26.1 and 26.2 are connectable to an electrical power source via connectors 28.

In this embodiment they are connected in parallel.

The heating passages 22 are in communication with each other via an intermediate passage 30, also drilled into the housing 1 2 and closed off by a plug 32.

Also in this embodiment, the switch passage 24 is downstream of the heating passages 22 and is in communication with the heating passages 22 via an intermediate passage 34. The passage 34 is again drilled into the housing 12 and closed by a plug 36.

The switch passage 24 contains a switch comprising a fixed contact 38 and a movable contact 40 which is provided at one end of an arm 42. The contacts 38 and 40 are of silver while the arm 42 is of a corrosion-resistant material.

The arm 42 is pivoted at 44 and has a bi-metal strip 46 welded to it. The bi-metal strip 46 is directly in the path of fluid flowing from the intermediate passage 34 to the outlet 1 8 and will thus be affected by changes in temperature in the water. The bi-metal strip 46 is also impinged upon by the water emitted from the intermediate passage 34 so that while fluid is flowing from the intermediate passage 34 to the outlet 1 8, the movable contact 40 will tend to move away from the fixed contact 38. This action is additionally assisted by a vane 48 near the outlet 18, and fixed to the arm 42.

As will be appreciated, an air pocket is formed in the region 50 of the switch passage 24 above the outlet 1 8 so that the contacts 40 and 38 are not immersed in water.

An adjustable stop or anchor 52 is provided within the plug 36. While water is flowing through the switch passage 24, the bi-metal strip 46 abuts against the anchor 52 and the contacts 40 and 38 are open. When the bi-metal strip is heated by the water flowing past it, its lower end will bend thereby allowing the movable contact 40 to move towards the fixed contact 38. If sufficiently heated, the contacts 40 and 38 will thus close.

The arm 42 is arranged in such a way that when no water is flowing through the switching passage 24 and before the bi-metal strip 46 is heated, the movable contact 40 will be biassed under gravity into contact with the fixed contact 38 provided the passage 24 is arranged with its axis vertical.

If the switch in the passage 24 is to be flowresponsive only, then the bi-metal strip 46 is replaced by a conventional blade which may be an extension of the arm 42.

Referring now to Figures 2 and 3, a regulating valve is generally indicated by reference numeral 60. The valve includes a valve body 62 having an outlet 64 which, in use, will be connected via the piping 1 6 of Figure 1 to the heater 10.

The body 62 defines a socket at its inlet end and in which is screw-threadedly located a removable spigot 66. The spigot 66 serves a number of purposes. Firstly, it serves to locate a resiliently flexible washer 68 at the inner end of the socket in the body 62. The washer 68 has a central aperture 70 which is in alignment with the bore of the outlet 64.

Secondly, the spigot 66 serves to permit connection of an inlet pipe 71 to the valve 60 by means.of a union 72.

Thirdly, the spigot 66 has locating means in the form of a nut 74 screw-threaded thereon and which serves to locate the valve 60 on a support plate 76. The support plate 76 will, in practice, form part of a cabinet which will be described with reference to Figure 4.

As shown in Figure 3, as the inlet pressure to the valve increases, the washer 68 is deformed by such pressure against a conical seat at the entrance to the bore of the outlet 64. This causes the aperture 70 to become effectively smaller.

The applicant has found that over a relatively wide range of inlet pressures, the maximum flow rate through the valve remains substantially constant.

Referring now to Figures 4 and 5, the heater 10 and valve 60 are shown mounted on a rear panel 78 of a cabinet having a door 80. In another embodiment, the heater and valve may be mounted in a box, e.g. of moulded synthetic plastics material.

The outer front face of the door 80 shown in Figure 5 has an indicator light 82 which will illuminate when the heater elements 26.1 and 26.2 are energised. It also has an 'on' button 84 and an 'off' button 86, the purpose of which will be described with reference to Figure 6. The zone 88 on the door 80 may have a mirror or other decorative material thereon. Instead of being separate, the indicator light 82 can be incorporated into the 'off' button 86.

The panel 78 of the cabinet also has a relay 90 and a connector block 92 mounted thereon.

Apertures 94 permit insertion of an electric cable from a mains supply. The door 80 is maintained in its closed position by screw (not shown) passing through an aperture 96 and insertable into a block 98.

Referring now to Figure 6, the electrical circuitry of the unit is shown. In use, operation of the 'on' switch 84 will cause power to be fed from the mains supply terminals 100 to the relay 90.

The relay 90 has three points, 90.1,90.2, and 90.3. The points 90.1 serve as a hold circuit for the 'on' switch 84 and maintain the relay 90 in the energised position. The points 90.2. and 90.3 cause energisation of the heater elements 26.1 and 26.2.

Thus, under normal operating conditions, water fed through the heater 10 will be heated once the 'on' button 84 has been depressed. It will be noted that while the relay 90 is energised, the indicator light 82 will also be illuminated.

In order to stop heating of the water, the 'off' button 86 is depressed. This short-circuits the relay 90 thereby causing its points to open and de-energising the heater elements 26.1 and 26.2.

In the event that water ceases to flow through the switch passage 24 of the heater 10, as previously described, this will cause the movable contact 40 to make contact with the fixed contact 38 thereby again short-circuiting the relay 90 and de-energising the heater elements 26.1 and 26.2.

Similarly, in the event of the water reaching a predetermined high temperature, the bi-metal strip 46 will bend causing the movable contact 40 to make contact with the fixed contact 38 of the switch. Again, the relay 90 is short-circuited and the heater elements 26.1 and 26.2 are deenergised.

It will be noted that the circuitry is not selfresetting so that once either the 'off' button 86 is depressed or the contacts 40 and 38 close, in order to reinitiate heating, the 'on' button 84 must be depressed.

Various modifications to the invention as illustrated, are possible. For example, an additional switch could be wired in series with the relay contacts 90.3 so that only when such switch is closed, will both heater elements 26.1 and 26.2 be energised. Furthermore, instead of the valve 60 being positioned remote from the heater 10, it may be integrally formed with the inlet 14 of the heater 1 0.

The unit may be mounted in any convenient position, e.g. in a shower, with a suitable tap upstream thereof. The temperature of the water emitted from the unit can be controlled by adjusting the rate of flow of the water by means of the tap. The maximum rate of flow is determined by the regulating valve 60. If the input water supply is turned off, the switch contacts 40 and 38 will close thereby preventing energisation of the heater elements. Even if the 'on' button 84 is depressed while the contacts 40 and 38 are closed, no power will be supplied to the heater elements 26.1 and 26.2.

The invention illustrated provides a heater unit which can be inexpensively manufactured. The provision of the units in a cabinet makes it easy to service. Even though the heater elements 26.1 and 26.2 are in direct contact with the water, there is a sufficient column of water between the inlet and the heater 10 in piping 16, and between the heater 10 and the outlet in piping 20 to prevent any danger of an electrical shock being passed to a user via the water. It is believed that the device will be economical in use in comparison to hot water geysers as electricity is only consumed while the heater is operated and water being drawn off. The use of the regulating valve 60 allows the unit to be used with a wide variety of inlet pressures with flow control achieved by a simple tap. As the heater 10 has the heater elements 26.1 and 26.2 in direct contact with the water, high energy conversion efficiency is obtained. The close proximity of the contacts 40 and 38 to the heater elements 26.1 and 26.2, allows a quick response time so that scalding of a user by too hot water being emitted, can be prevented. Over-heating of the heater elements 26.1 and 26.2 is also thereby avoided.

Claims

1. A heater which includes a solid housing having an inlet and an outlet for fluid to be heated, the housing having formed therein at least one heating passage and a switch passage intermediate the inlet and the outlet, the heating passage containing an electrical heater element which, in use, is in direct contact with the fluid to be heated and which is connectable to an electrical power source, and the switch passage containing a switch at least partially in the fluid flow path through the switch passage and being adapted to control the supply of current to the heater element, the switch being responsive to variations in fluid flow and/or to predetermined variations in temperature of the fluid.

2. A heater as claimed in Claim 1, in which the housing has a plurality of heater elements therein.

3. A heater as claimed in Claim 2, in which each heater element is separately energisable via suitable switch means.

4. A heater as claimed in any one of the preceding claims, in which the passages in the housing are formed by drilling and closed Qf by suitable plugs.

5. A heater as claimed in any one of the preceding claims, in which the switch passage is in communication with heating passage via an intermediate passage, the intermediate passage being in close proximity to the outlet of the housing and the fluid flow path through the switch passage being relatively short but sufficient to permit fluid to impinge on pontoon of the switch.

6. A heater as claimed in any one of the preceding claims, in which an air pocket is formed in the switch passage above the fluid flow path to permit operation of the contacts of the switch in the air pocket.

7. A heater as claimed in any one of the preceding claims, in which the switch comprises a fixed contact and a movable contact provided at one end of an arm, the arm being pivoted intermediate its ends with its other end in the fluid flow path.

8. A heater as claimed in Claim 7, in which said other end of the arm is in the form of a bi-metal strip.

9. A heater as claimed in Claim 8, in which the bi-metal strip co-operates with an anchor which is adjustable to permit adjustment of the sensitivity of the of the switch.

10. A heater as claimed in any one of the preceding Claims 7 to 9, in which the arm has a vane in the fluid flow path for assisting movement of the arm in response to fluid flow.

11. A heater as claimed in any one of the preceding Claims 7 to 10, in which the fixed contact is adjustable to permit adjustment of the sensitivity of the switch.

12. A regulating valve adapted for use in conjunction with the heater as claimed in any one of the preceding claims, the valve including a valve body having an outlet connectable to the inlet of the heater, the body defining a socket at its inlet end and containing a removable spigot, the spigot serving to locate a resiliently flexible washer fitted in the inner end of the socket, the spigot protruding from the socket and being adapted for connection to a fluid source and the spigot having locating means for locating it on a support, the resilient washer having a central aperture which, in use, as the washer is resiliently deformed by increase of pressure of fluid, restricts the degree of fluid flow through the valve.

13. A regulating valve as claimed in Claim 12, in which the outlet of the valve is in the form of a further spigot integrally formed with the valve body.

14. A regulating valve as claimed in Claim 12 or 13, in which the locating means includes a threaded nut provided on the spigot.

1 5. A heating unit which includes a heater as claimed in any one of the preceding Claims 1 to 11, in combination with a regulating valve as claimed in any one of the preceding Claims 12 to 14.

16. A unit as claimed in Claim 15, in which the valve body is integrally formed with the housing of the heater.

17. A unit as claimed in Claim 1 5 or Claim 16, in which the heater and the valve are mounted in a cabinet having mounting means for mounting the cabinet on a surface.

18. A unit as claimed in Claim 17, in which the heater and valve are mounted on a back panel of the cabinet, and are enclosed by a door or cover.

19. A unit as claimed in Claim 18, in which the cabinet also houses electrical circuitry responsive to the switch of the heater and adapted to control the energisation of the heater element.

20. A unit as claimed in any one of the preceding Claims 1 5 to 19, which includes indicator means for indicating when the heater element is energised.

21. A heater, substantially as described and as illustrated herein.

22. A regulating valve, substantially as described and as illustrated herein.

23. A heating unit, substantially as described and as illustrated herein.