GB1281321A - Improvements in or relating to low-temperature warning devices - Google Patents

Improvements in or relating to low-temperature warning devices

Info

Publication number
GB1281321A
GB1281321A GB6770A GB6770A GB1281321A GB 1281321 A GB1281321 A GB 1281321A GB 6770 A GB6770 A GB 6770A GB 6770 A GB6770 A GB 6770A GB 1281321 A GB1281321 A GB 1281321A
Authority
GB
United Kingdom
Prior art keywords
temperature
chamber
volume
predetermined temperature
vapour
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB6770A
Inventor
Michael Gilbert Tanner Hewlett
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Plessey Co Ltd
Original Assignee
Plessey Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Plessey Co Ltd filed Critical Plessey Co Ltd
Priority to GB6770A priority Critical patent/GB1281321A/en
Publication of GB1281321A publication Critical patent/GB1281321A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K5/00—Measuring temperature based on the expansion or contraction of a material
    • G01K5/32—Measuring temperature based on the expansion or contraction of a material the material being a fluid contained in a hollow body having parts which are deformable or displaceable
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B19/00—Alarms responsive to two or more different undesired or abnormal conditions, e.g. burglary and fire, abnormal temperature and abnormal rate of flow
    • G08B19/02—Alarm responsive to formation or anticipated formation of ice

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Road Signs Or Road Markings (AREA)

Abstract

1281321 Temperature indicators PLESSEY CO Ltd 23 Dec 1970 [1 Jan 1970] 67/70 Heading G1D [Also in Division G2] A device for indicating, for example, when the temperature of a road surface has fallen to a level at which ice formation can occur comprises a light reflective surface 3 and means to change the colour of light reflected from the surface upon reaching a predetermined temperature. As shown, the reflective surface 3 to which incident light is directed forms part of a sealed chamber which is further defined by a transparent wall 5 and an elastomeric cylindrical wall 7 and in which is located a coloured liquid and its vapour or a gas. Above the predetermined temperature the pressure of the vapour or gas above the liquid is sufficient to maintain the volume of the chamber large enough to ensure the coloured liquid occupies only a small volume at the base of the chamber, Fig. 1 (not shown), whereas below the predetermined temperature the pressure of the vapour or gas is small enough to allow the volume of the chamber to decrease and urge the coloured liquid substantially to cover the reflective surface and thereby to affect the colour of the reflected light. The change of volume of the chamber may be gradual or a snap action device may be provided to ensure a sudden volume change at the predetermined temperature. In further arrangements a filter may be mechanically moved by a temperature sensitive element into the path of reflected light or a temperature sensitive element may be arranged to interchange optical elements of different colours in accordance with temperature changes.
GB6770A 1970-01-01 1970-01-01 Improvements in or relating to low-temperature warning devices Expired GB1281321A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB6770A GB1281321A (en) 1970-01-01 1970-01-01 Improvements in or relating to low-temperature warning devices

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB6770A GB1281321A (en) 1970-01-01 1970-01-01 Improvements in or relating to low-temperature warning devices

Publications (1)

Publication Number Publication Date
GB1281321A true GB1281321A (en) 1972-07-12

Family

ID=9697822

Family Applications (1)

Application Number Title Priority Date Filing Date
GB6770A Expired GB1281321A (en) 1970-01-01 1970-01-01 Improvements in or relating to low-temperature warning devices

Country Status (1)

Country Link
GB (1) GB1281321A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2118228A (en) * 1982-03-13 1983-10-26 Edward Raymond Stevens Hazard warning device
GB2119835A (en) * 1982-04-21 1983-11-23 Carl Patrick Harrell Ice hazard warning sign
GB2121460A (en) * 1982-04-27 1983-12-21 Carl Patrick Harrell Road ice warning studs

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2118228A (en) * 1982-03-13 1983-10-26 Edward Raymond Stevens Hazard warning device
GB2119835A (en) * 1982-04-21 1983-11-23 Carl Patrick Harrell Ice hazard warning sign
GB2121460A (en) * 1982-04-27 1983-12-21 Carl Patrick Harrell Road ice warning studs

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee