GB2200449A

GB2200449A - Temperature, temperature/time indicators

Info

Publication number: GB2200449A
Application number: GB08630672A
Authority: GB
Inventors: William Nevil Heaton Johnson; Robert Neale
Original assignee: Scientific Applied Research SAR PLC
Current assignee: Scientific Applied Research SAR PLC
Priority date: 1986-12-23
Filing date: 1986-12-23
Publication date: 1988-08-03
Also published as: GB8630672D0

Abstract

An indicator is provided which undergoes a marked colour change when a desired temperature is reached or has been maintained for a predetermined time. In one embodiment, the indicator is a water soluble die intended to be put into a bath being run so that the user can tell at a glance whether the bath water is too hot or too cold. In another embodiment the indicator is in the form of a pigment incorporated in a "boil-in-bag" food item and is arranged to change colour when the item has been boiled long onough to be cooked.

Description

"Temperaturelheating or cooling indicator?? THE PRESENT INVENTION relates to means for providing an indication of the temperature of an item or body or of whether or not a body has been heated or cooled for a predetermined time to a desired degree.

According to one aspect of the invention there is provided means for providing an indication of the temperature of an item or body, or of whether or not a body has been heated or cooled for a predetermined time to a desired degree, comprising a colour indicator adapted to undergo a perceptible colour change when the desired temperature or degree of heating or cooling has been reached.

The colour indicator may be adapted to respond simply to changes in temperature, or may be arranged to undergo a perceptible colour change when a predetermined temperature has been maintained for a predetermined time.

The above and other, preferred, features of the invention will become more apparent from the following description of embodiments thereof.

In one embodiment of the invention, a temperature indicator, in the form of a water soluble dye, is incorporated in a product intended to be dissolved in bathwater, for example in a bath cube or bath crystals or in a liquid bath additive. The dye is so composed and chosen that it will undergo a colour change according to the temperature of the bath water in which it is dissolved so that the user can tell at a glance whether the bath water is too hot or too cold. For example, the dye may be arranged to be blue when the water is too cold and red when the water is too hot, and possibly to be some intermediate shade, or colourless, when the temperature is ideal.The dye may be arranged to undergo a relatively abrupt colour change over a narrow temperature range or may be arranged to change progressively over a wider temperature range so that there will be a whole range of colours for a range of temperatures and the user may come to know which particular colour is appropriate for the preferred temperature.

This embodiment of the invention may be of particular utility in institutions such as hospitals, where pressure of work on staff makes it difficult to ensure that bath temperature is adequately tested by conventional means before patients are placed in baths.

Similarly, a water soluble dye of this general type, adapted to respond to temperatures in a different range, may be utilised in a swimming pool, for example, to provide an indication of the temperature.

It will be appreciated that in the above embodiments, the dyestuffs utilised are such as not to be significantly attracted to the human skin and, in any case, are used in concentrations so small as not to perceptibly dye the skins of the bathers.

As another example, such a dye or pigment may be incorporated in a plastics bag containing a food item of the "boil-in-bag" variety and may be arranged to undergo a perceptible colour change when the bag and the food item have been boiled for long enough to cook the item satisfactorily, so that the cook can tell simply by looking at the bag whether or not the food item has been cooked. Alternatively, such a pigment may be incorporated in an indicator body, for example a ball or ring, adapted to be boiled with the food item or otherwise to accompany the food item during cooking, the appropriate indicator element being selected according to the method of cooking and the item to be cooked.

It will be appreciated that there are many other applications where a visual indication of colour change related to temperature may usefully be provided in accordance with the present invention.

Claims

1 Means for providing an indication of the temperature of an item or body, or of whether or not a body has been heated or cooled for a predetermined time to a desired degree, comprising a colour indicator adapted to undergo a perceptible colour change when the desired temperature or degree of heating or cooling has been reached.

2. Means for providing an indication of the temperature of a body of water, including a water-soluble dye adapted to undergo a perceptible colour change in passing a critical temperature or passing through a critical temperature range.

3. Means for providing an indication of when a food has been cooked, including an article adapted to accompany the food during cooking and incorporating a pigment adapted to undergo a perceptible colour change when the item and the food have undergone the necessary heating/time procedure for cooking.

4. Means according to claim 3 wherein said article adapted to accompany the food is a container or bag containing the food.

5. Means according to claim 1 and substantially as herein described.

6. Any novel feature or combination of features described herein.