GB2267952A

GB2267952A - Thermostats and thermostatic radiator valve

Info

Publication number: GB2267952A
Application number: GB9312249A
Authority: GB
Inventors: Derek Gorman; Lothar Braun
Original assignee: Drayton Controls Engineering Ltd
Current assignee: Drayton Controls Engineering Ltd
Priority date: 1992-06-17
Filing date: 1993-06-14
Publication date: 1993-12-22
Anticipated expiration: 2013-06-14
Also published as: GB2267952B; GB9212805D0; SE9302096D0; SE9302096L; GB9312249D0; DE4320103A1

Abstract

A thermostat or thermostatic radiator valve (1) for controlling the heat output of a radiator in order to achieve and maintain a desired ambient temperature in a space has attached to it a temperature sensitive liquid crystal display (8) arranged to indicate a temperature representative of the current ambient temperature. <IMAGE>

Description

2267952 THERMOSTATS AND THERMOSTATIC RADIATOR VALVES The present invention

relates to thermostatic radiator valves and to thermostats.

Known thermostatic radiator valves used to control the heat output of radiators in order to maintain a relatively constant ambient temperature comprise only a simple scale to indicate the position of an adjustable temperature setting member, the scale giving no direct indication of the resulting ambient temperature. Indeed, any correlation that exists between scale reading and ambient temperature depends upon the room in which it is positioned and its position with respect to the room and the associated radiator.

According to a first aspect of the present invention there is provided a thermostatic radiator valve having attached to it a temperature sensitive liquid crystal display arranged to provide a display which changes depending upon the temperature of the display, to assist a user in adjusting the valve to achieve a desired ambient temperature.

The liquid crystal display may be arranged to display a plurality of distinct values, for example, depending upon the change of translucence of distinct liquid crystal display elements to reveal numeric indicators provided beneath those elements. Thus, according to a preferred embodiment of the above first aspect the liquid crystal display comprises a backing portion and a plurality of discrete temperature indicators arranged on a front face of the backing portion, each indicator comprising a number, representing a discrete temperature, and a layer of liquid crystal positioned on top of the number and arranged to be substantially transparent when its temperature is within a given range about the temperature represented by the number and arranged to be substantially opaque when its temperature is outside said range.

According to another embodiment the temperature values are displayed as colour changes of portions of liquid crystal material. Numeric temperature indicators are preferably provided in association with respective portions.

According to a further embodiment the temperature display comprises a printed "tens" digit, e.g. "2", adjacent a multi-segment display the segments of which comprise a coating or encapsulation of liquid crystal arranged to be substantially transparent within a given temperature range, the segments being so arranged and the respective given temperature ranges being so chosen that the multi-segment display displays a numeral corresponding to the "units" digit of the temperature value to be displayed. For example the multi-segment display may be arranged to display the numerals "V', If 219, 913 " and " 4 If to form with the tens digit temperature displays of "2111, 112211, "2X' and "24".

According to a still further embodiment the valve comprises only one of said temperature sensitive liquid crystal displays, the display being in the form of no more than one liquid crystal element and being arranged to indicate when the temperature of the display has reached a certain temperature.

According to a second aspect of the invention there Is provided a thermostat having attached to it only one temperature sensitive liquid crystal display arranged to indicate when the temperature of the display has reached a certain temperature, to assist the user in adjusting the thermostat to achieve a desired ambient temperature, the display being in the form of no more than one liquid crystal arrangement.

According to a third aspect of the invention there is provided a method of controlling the temperature of a space using a thermostatic radiator valve according to the above first aspect or a thermostat according to the above second aspect.

For a better understanding of the present invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:- Figure 1 shows a side view of a thermostatic radiator valve having a temperature display; Figure 2 shows a plan view of the valve of Figure 1 having a modified temperature display; Figure 3 shows a side view of a modified radiator valve having a temperature display; Figure 4 shows a view of a component of the valve of Figure 3; Figures 5A and 5B show a thermostatic radiator valve having a single element temperature display; and Figures 6A and 6B show the two mounting orientations of a thermostatic radiator valve.

Figure 1 shows a thermostatic radiator valve 1 comprising a valve body 2 containing a controllable valve element and having ports 5 and 6 for connection to a hot water supply and a radiator. The functions of these ports are interchangeable. Attached to the valve body and separated from it by a ribbed heat shield 10 is a bezel 3. A metallic head portion 4 of good heat conductivity having a dome-shaped end is mounted in the bezel 3. The head portion contains a thermostat for controlling the valve element and is rotatable within the bezel to adjust the temperature setting of the thermostat. For a given setting the valve element is automatically adjusted by the thermostat to tend to maintain the temperature at the head portion 4 at a substantially constant value. Bezel 3 has a head portion position indicator 7 which projects outwardly. Alternatively or in addition, bezel 3 may have a cut- out window 17 (shown dashed) through which a setting for the valve, printed on the underlying surface of the head portion 4, may be viewed.

The valve as so far described is already marketed 5 in one form by Drayton as valve T.R.V.3.

Located around a circumferential exposed region of the head portion 4 is a temperature display strip 8 arranged to display a temperature corresponding to the ambient temperature within a display range. This range may be, for example, from 18 to 240C. The strip is in contact with, and thus in heat exchange relationship with, the head portion 4 so that the displayed temperature is substantially that of the head portion and thus of the temperature to which the thermostat is responsive. The strip comprises a backing sheet and a plurality of discrete temperature indicators 9 arranged sequentially along the backing strip. Each indicator comprises a number, representing a unique temperature from within the display range, printed on the backing strip and a layer of liquid crystal coated or encapsulated on top of, so as to cover, the printed number. For each number the associated liquid crystal is selected to be of a type which is substantially transparent in a temperature range about the temperature represented by the number. The range may be, for example, from 10C below the represented temperature to 10C above it. The temperature representable by each successive indicator along the strip increases in equal steps from the bottom to the top of the display range. At a given temperature only the number or numbers 9 covered by liquid crystal which is sufficiently transparent at that temperature will be visible. In Figure 1 the numbers which remain hidden are shown dashed. The head portion 4 may have numeric indicators printed around its circumference and alignable with the position indicator 7 to aid in setting the valve.

Whilst Figure 1 shows the temperature display strip located on the head portion 4, the strip could alternatively be located on the bezel 3 or on any part of the valve not in direct thermal contact with the valve body 2 in order to sense ambient temperature.

Figure 2 shows a thermostatic radiator valve as shown in Figure 1 but modified in that a temperature display is located on the dome-shaped end of the head portion 4 rather than around its circumference. In this embodiment, six sectors are arranged on a diskshaped backing sheet. Two sectors 18 contain only a printed message, "FROST" and "MAX" respectively, to indicate, when aligned with the position indicator 7, that the valve is set approximately to the minimal frost protection setting or to a maximum setting ; c,,n respectively. The remaining four sectors comprise discrete display elements as described above.

It will be appreciated that the present invention is not limited only to liquid crystal displays of the type described with reference to Figures 1 and 2. For example, either embodiment may have a display of the type having liquid crystal regions which change colour in or over a given temperature range with temperature defining legends being printed adjacent to or on top of the display element. One such embodiment will now be described with reference to Figures 3 and 4.

Figure 3 shows a thermostatic radiator valve of the type as shown in Figure 1 but modified in that a temperature display strip 15 is located on the head portion 4 so that a section of the strip is visible through a window 14. In this embodiment, the window is generally V-shaped. Figure 4 shows a view of the strip 15 itself, which comprises five discrete temperature display elements 13 spaced apart on a backing strip. Each element 13 comprises an encapsulated layer of liquid crystal on top of the backing strip, the liquid crystal being of a type which produces a visible colour change in the element over a temperature range. For example, the element may change colour from blue to green and then to black in response to a temperature change from 19 to 20 and then to 210C. The liquid crystal materials comprising each of the five elements are selected to provide temperature information over the range 16 to 240C. Printed on top of each encapsulated layer of liquid crystal is a number corresponding to the temperature, in OC in the illustrated embodiment, corresponding to the centre of the temperature range over which the underlying liquid crystal produces a colour change.

The display strip is located on the head portion 4 with an angular position such that the temperature response range of the display element at the centre of the window 15 is centred substantially on the temperature setting of the thermostat. The window is shaped so as to display at least one discrete display element on either side of the centred element to aid in setting the valve.

In addition to the temperature display elements 13 the display strip also comprises three status elements 16 which display printed status messages "OFF", "FROSTly and "MAX" corresponding respectively to the head portion 4 angular setting in which the valve is fully off, is set to a minimal frost-protection setting or is fully on.

The method of manufacture and function of the above described liquid crystal temperature displays are known to those skilled in the art and details can be gleaned from, for example, United Kingdom Patent Specification 1439161 which discloses a digital thermometer comprising discrete segments having liquid crystal layers which become transparent over a given temperature range to reveal underlying numerals. Reference may also be made to United Kingdom Patent Specifications 1138590 and 1447092 which disclose a temperature display which comprises segments of liquid crystal which change colour in response to temperature changes.

The use of the above described thermostatic radiator valves in controlling the temperature of a space will now be described. The user first selects an approximate, desired, room temperature by rotating the head portion 4 of the valve until the segment of the multi-segment display 4, 13 corresponding approximately to the desired temperature is positioned adjacent to the position indicator 7 or is centred in the window 14. When the temperature in the room has stabilized the user views the temperature display strip or that portion of the display strip currently visible through the window. If the display element currently showing as being closest to the centre of its temperature activation range, for example the element of the embodiment described with reference to Figures 3 and 4 which is green, is the element positioned by the user to be adjacent to the position indicator 7 or to be centred in the window 14, then the ambient temperature has approximately attained the desired temperature and no further adjustment of the valve by the user is required. However, if the element showing itself to be currently closest to the centre of its temperature activation range corresponds to a temperature above or below the desired temperature, due to a noncorrespondence between angular position of the display and the thermostat setting or some other reason, the user rotates the head portion clockwise or anticlockwise respectively, for example to advance the display by one segment. This adjustment process is repeated intermittently by the user until the display element corresponding to the desired temperature is seen to be at the centre of its activation range after the temperature has stabilised.

Figures 5A and 5B show a thermostatic radiator valve having a single liquid crystal temperature indicator 19 mounted on the side of the head portion, 4. The indicator comprises a backing strip on the front of which a suitable symbol or message is printed. A layer of liquid crystal is coated or encapsulated on top of, so as to cover, the printed symbol or message. The liquid crystal is of a type described above, with reference to Figures 1 to 4, which is transparent only over a given temperature range so that when the temperature of the display is within that range the symbol or message is visible.

In particular, Figures 5A and 5B show an embodiment designed to indicate to a user when the ambient temperature is within a comfort/economy range. Figure 5A shows the state of the display when the temperature of the display is below 190C or above 210C, i.e. no symbol displayed. Figure 5B shows the state of the display when the temperature of the display is between 190C and 210C, i.e. the symbol 'W' is displayed. Preferably, a change in the background colour of the display, e.g. from black to red, accompanies the display of the symbol "e". Using indicators of this type it is possible to provide displays which are visible at a glance and which do not require close inspection, thus simplifying the task of temperature control.

As it is the case that, at any one time, the temperature in various locations around a radiator may vary considerably, valves to be attached in different locations may be provided with indicators which react over different temperature ranges in order to achieve a consistent response to the ambient temperature. For -g- example, with a horizontally mounted valve as shown in Figure 6A, in order to achieve a satisfactory comfort/economy range the range over which the indicator displays the "e" symbol may be from 190C to 210C. In order to achieve the same ambient response, the temperature range over which the indicator on a vertically mounted valve, as shown in Figure 6B, displays the "e" symbol may be from 210C to 230C.

Alternatively, thermostatic valves may be provided with a "single elemenC indicator which displays a message or symbol and/or a colour change only when the temperature rises above a certain temperature, e.g. 190C.

It will be apparent that the indicator described with reference to Figures 5 and 6 may be mounted on a thermostat, for example of the wall mounted type used to control a central heating system, again allowing "at a glance" controllability.

Claims

1. A thermostatic radiator valve having attached to it a temperature sensitive liquid crystal display arranged to provide a display which changes depending upon the temperature of the display, to assist a user in adjusting the valve to achieve a desired ambient temperature.

2. A valve according to claim 1, wherein the liquid crystal display is arranged to display a plurality of values.

3. A valve according to claim 2 wherein the display comprises a plurality of discrete display elements each of which comprises liquid crystal exhibiting a change in optical property over a mutually distinct temperature range.

4. A valve according to claim 3 and comprising numeric temperature indicators in association with respective elements and arranged to be visible regardless of the change of optical property of the associated element.

5. A valve according to claim 4 wherein the elements are arranged to display respective ones of said plurality of values.

6. A valve according to any one of the preceding claims wherein the liquid crystal display utilises a change in liquid crystal translucence to reveal numeric indicators beneath the liquid crystal.

7. A valve according to claim 6 wherein the display comprises a backing portion and a plurality of discrete temperature indicators arranged on a front face of the backing portion, each indicator comprising a number, representing a discrete temperature, and a layer of liquid crystal positioned on top of the number and arranged to be substantially transparent when its temperature is within a given range about the temperature represented by the number and arranged to -11 be substantially opaque when its temperature is outside said range.

8. A valve according to any one of claims 1 to 5 wherein the liquid crystal display comprises liquid crystal such as to produce a change of colour of the display elements.

9. A valve according to any one of claims 3 to 8 wherein the elements are arranged in a temperature ordered sequence.

10. A valve according to claim 9 wherein the temperature display comprises status messages to indicate more extreme settings of the valve.

11. A valve according to any one of claims 3 to 10 wherein the elements are arranged sequentially along a strip.

12. A valve according to any one of claims 3 to 11 wherein the temperature display comprises a printed "tens" digit adjacent a multi- segment display the segments of which comprise respective ones of said plurality of discrete display elements, said elements being arranged to be substantially transparent within a given temperature range, the segments being so arranged and the respective given temperature ranges being so chosen that the multi-segment display displays a numeral corresponding to the "units" digit of the temperature value to be displayed.

13. A valve according to any one of the preceding claims comprising a bezel and a head portion, the head portion being attached to the bezel and being rotatable with respect thereto so as to adjust the setting of a thermostat of the valve, there being means provided to indicate the angular position of the head portion with respect to the bezel.

14. A valve according to claim 13 when appended to claim 11, wherein the indicating means comprises a window provided in the bezel, the strip being affixed to the head portion so that a section of the strip can be viewed through the window.

15. A valve according to claim 14 wherein the window is substantially V-shaped.

16. A valve according to claim 14 or 15 wherein at least three sequential display elements can be viewed simultaneously through the window.

17. A valve according to claim 1 comprising only one of said temperature sensitive liquid crystal displays, the display being in the form of no more than one liquid crystal element and being arranged to indicate when the temperature of the display has reached a certain temperature.

18. A thermostat having attached to it only one temperature sensitive liquid crystal display arranged to indicate when the temperature of the display has reached a certain temperature, to assist the user in adjusting the thermostat to achieve a desired ambient temperature, the display being in the form of no more than one liquid crystal arrangement.

19. A valve according to claim 17 or a thermostat according to claim 18, wherein the display provides no numeric indication of temperature.

20. A valve or thermostat according to claim 19 wherein the display reveals, when the certain temperature is reached, a non-numeric symbol to define an operating state.

21. A valve or thermostat according to claim 20 wherein, when the temperature of the display rises above said certain temperature by a certain amount, the non-numeric symbol is hidden.

22. A thermostatic radiator valve substantially as hereinbefore described with reference to Figure 1, Figures 1 and 2, Figures 3 and 4 or Figures 5 and 6 of the accompanying drawings.

23. A thermostat substantially as hereinbefore described.

24. A method of controlling the temperature of a space using a thermostatic radiator valve according to any one of claims 1 to 17 and 19 to 22 or a thermostat 5 according to any one of claims 18 to 21 and 23.

25. A method according to claim 24 comprising the steps of setting the valve or thermostat to an initial position, allowing the temperature of the space to stabilise, observing which temperature value is currently displayed by the temperature display, resetting the valve or thermostat so as to change the temperature in a direction towards a desired space temperature and repeating the steps of allowing the temperature to stabilise and of re-setting until the desired temperature corresponds to the currently displayed temperature value.

26. A method of controlling the temperature of a space substantially as hereinbefore described with reference to Figure 1, Figures 1 and 2, Figures 3 and 4, or Figures 5 and 6 of the accompanying drawings.