Patent ID: 7049554

Claim:
An adjustable heater for acquaria, comprising a substantially tubular container within which are housed an electrical heating element, a switch comprising fixed contacts and moving contacts capable of electrically connecting the said heating element to an outside source of electrical power, a temperature sensor having a bi-metal strip capable of detecting the temperature of the liquid and interacting with the said switch to move it from a closed position to an open position when a predetermined temperature is reached, wherein the moving contacts of the switch are secured to a free end of the bi-metal strip, the other end of the bi-metal strip being electrically insulated so as to prevent current from passing through it, said heating element comprising at least one electrical resistance having a first terminal directly connected to a first conductor of a supply cable from the source of electrical power and a second terminal which can be connected to a second conductor of the said supply cable through said switch, wherein the other end of the said strip is anchored to a supporting frame through an elastic connecting member, adjustment means being provided which act on the elastic connecting member to vary the preloading on the latter and position the free end of bi-metal strip, and escapement means for maintaining the fixed and moving contacts in a mutually connected condition.