Scale indicator for domestic coffee machine - has heat sensor in loose thermal coupling with hot water pipe for optional positioning

摘要

The scale indicator is for a coffee maker having a throughflow heater provided with a heat sensor (32) which is in loose thermal coupling with the hot water pipe (26) and gives off a signal in the event of an increased rise in temperature owing to scaling up. This heat sensor has a response temperature which is reached at a specific minimum time after the hot water has turned to steam. Since this response temperature is reached at the point of installation of the heat sensor the latter can be mounted at any point on the hot water supply pipe and can thus be readily visible without great expenditure. The sensor can be coupled to the hot water pipe by a thermally insulating material (32) which allows the rise in temperature in the pipe to be passed along only slowly.