FIRE PROTECTION SYSTEM
A manual call point and optical beam smoke detector. The manual call point includes a housing, a plurality of components located within the housing including a mechanism operable to trigger an alarm, and a self-regulating heater. The self-regulating heater is configured to maintain a constant temperature within the housing. The optical beam smoke detector includes a housing having a window, a transmitter and/or a receiver located within the housing, and a heater located within the housing. The heater is configured to maintain a temperature difference between an interior of the housing and an exterior of the housing below a threshold temperature difference.
1 . A manual call point (MCP), comprising:
a housing;
a plurality of components located within the housing, wherein the plurality of components comprise a mechanism operable to trigger an alarm; and
a self-regulating heater, wherein the self-regulating heater is configured to maintain a temperature within the housing.
2 . A manual call point as claimed in claim 1 , wherein the housing comprises a metal housing, and wherein the heater is arranged to contact the metal housing.
3 . A manual call point as claimed in claim 1 , further comprising a metal plate located within the housing, wherein the heater is arranged to contact the metal plate.
4 . An optical beam smoke detector, comprising:
a housing having a window;
a transmitter and/or a receiver located within the housing; and
a heater, wherein the heater is configured to maintain a temperature difference between an interior of the housing and an exterior of the housing below a threshold temperature difference.
5 . A smoke detector as claimed in claim 4 , wherein the heater comprises a self-regulating heater.
6 . A smoke detector as claimed in claim 4 , wherein the threshold temperature difference comprises a temperature difference less than 10° C.
7 . A smoke detector as claimed in claim 4 , further comprising a temperature sensor, wherein the sensor is configured to detect the temperature of an environment external to the housing.
8 . A smoke detector as claimed in claim 4 , further comprising a fan located within the housing, wherein the fan is configured to distribute heat throughout the interior of the housing.
9 . A manual call point or smoke detector as claimed in claim 1 , wherein the heater comprises a positive temperature coefficient (PTC) heater.
10 . A manual call point or smoke detector as claimed in claim 1 , further comprising a regulator configured to supply the heater with a voltage.
11 . A manual call point or a smoke detector as claimed in claim 10 , wherein the regulator comprises a buck boost regulator.
12 . A manual call point or smoke detector as claimed in claim 10 , wherein the regulator is configured to limit a maximum current provided to the heater.
13 . A fire protection system comprising a manual call point and/or a smoke detector as claimed in claim 1 .
14 . A method of operating a manual call point (MCP) that comprises a plurality of components located within a housing, wherein the plurality of components comprise a mechanism operable to trigger an alarm, the method comprising:
using a self-regulating heater to maintain a temperature within the housing.
15 . A method of operating an optical beam smoke detector that comprises a housing having a window, and a transmitter and/or a receiver located within the housing, the method comprising:
using a heater to maintain a temperature difference between an interior of the housing and an exterior of the housing below a threshold temperature difference.