How to distinguish between ordinary bimetallic thermometer and electric contact bimetallic thermometer?

Bimetallic thermometer is a kind of common of the thermometer, according to the different classification rules, can be further subdivided. According to the working principle of the different, we can put the bimetallic thermometer is divided into ordinary bimetallic thermometer ( WSS series bimetallic thermometer) And electric contact bimetallic thermometer ( WSSX series bimetallic thermometer) 。 So how do you distinguish between the two? Is actually see they work. Working principle of common bimetallic thermometer is composed of two layers of linear expansion coefficient difference between strong relatively large pieces of metal welded together to form thermal components, one end of the temperature sensing element for the fixed end, on the other side for the free end. When the temperature changes, because the bimetallic strip of material is different, linear expansion coefficient of relatively large differences, and produce different expansion and contraction, leading to the curving deformation of bimetallic strip, equipped with actuator (at the free end Dial pointer and temperature) So that it can directly show the temperature value. And the working principle of electric contact bimetallic thermometer is based on the ring around made of bent bimetallic strip. Side heated expands, turns the pointer, the instrument will show should value, and prevent environmental vibration in double metal internal filling or double metal part shows some separation and measurement to achieve seismic effect. Electric contact bimetallic thermometer is the use of lead contact changes when temperature changes, when contact with the upper and lower limits or disconnected at the same time, make the circuit of relay action, to call the police.