What problem should note using bimetallic thermometer

Bimetallic thermometer is medium in the industrial used to gauge the temperature of the initiative in the instrument is also one of the most popular temperature meter, it is a kind of field detection instrument suitable measurement, low temperature, can be used to measure gas, liquid, and the temperature of the steam. Bimetallic thermometer is mainly used in industry of element is one with two or more pieces of metal laminate composed of multilayer metal together. To improve the temperature measuring sensitivity, is usually made of metal spiral coil shape. When multi-layer metal temperature change, the layers of metal expansion or contraction, makes the spiral coil rolled up or let go. As a result of the spiral coil end fixed and the other end connected to a free rotating pointer, therefore, when the bimetallic strip feel the temperature change, Pointers can be on a circular dividing scale to indicate the temperature. This kind of instrument of temperature measurement range is usually - 40 ~ 550 ℃, the permissible error are scale label 1. About 5%. The next instrument with us the matters needing attention. Selection guidelines: according to the model, the dial diameter, precision grade, installation fixed form, temperature measuring range, protection tube material, length or insert depth and so on. Bimetallic thermometer is in use process should pay attention to the following: A, bimetallic thermometer heat tube immersed in measured medium length must be greater than the length of the thermal components, immersed in length is more than 100 mm, 0 50 ℃ range into greater than 150 mm in length, so as to ensure the accuracy of measurement. B, the bimetallic thermometer should not be used to measure open containers within the medium temperature, electric contact thermometer colorful vibration at work used in the control circuit of big occasions. C, bimetallic thermometer in custody, use the installation and transportation, should avoid collision protection tube, do not make the protection tube bending variant and the table when the spanner is used. D, thermometer in the case of normal use shall be regular inspection, is every six months. Electric contact thermometer is not allowed to work under strong shock, so as not to affect the reliability of the contact. Bimetallic thermometer, widely used under the condition of high mechanical strength requirements. And have waterproof, corrosion resistance, vibration resistance, intuitive, easy reading, no mercury pollution, strong and durable, etc. Alternative to many other forms of thermometer table, widely used in petroleum, chemical industry, machinery, ships, electricity, textile, printing and dyeing and other industrial and scientific research departments.