Principles of industrial bimetallic thermometer and the use process is introduced

1, the principle, in principle, scoring three categories: (temperature 1) Filling liquid type & ndash; When the temperature changes, the liquid will expand or contract accordingly. （ 2) Fill the gas type & ndash; When the temperature changes, the gas will expand or contract accordingly. （ 3) Bimetallic type & ndash; Bimetallic thermometer induction element is composed of two kinds of thermal expansion coefficient of different metal, spiraling, they can produce deformation according to the variation of temperature, indicating the temperature. Characteristics: compared with liquid filling thermometer, the thermometer almost non-existent environmental temperature error; Since there is no filling liquid, its use is very safe, No pollution of the environment) ； This thermometer has simple structure, reasonable price. Use place has the following three conditions: ( 1) Outdoor use, requiring high protection grade, corrosion, 2) With strong vibration occasions ( Stainless steel, the liquid type) （ 3) 2 inflammable and explosive occasions, thermometer dial scale & middot; The choice of material thermal department ( 1) Select temperature time, consider normal temperature under test shall be located in the range of temperature dial scale of 30% ~ 60%. When the temperature is beyond the scope, may cause the collapse of the meter. Thermometer, for example, in the course of carriage, the equator or frigid zone or stored in frigid zone, ZR - UHZ magnetic level gauge are turning to pay special attention to! Applications: if the actual measuring liquid temperature 40 ℃ ~ 60 ℃, then dial scale should choose 0 ~ 100 ℃. （ 2) Confirm whether joint fluid component material is suitable for liquid or gas under test. 3 different size, thermal minimum insertion type, temperature range and heat diameter to its shortest insertion depth. Not less than a third ( Insert/length) When ordering, select the specifications, you need to choose a suitable length, it is greater than the shortest insertion depth, to ensure the performance of the play. 4, environmental temperature compensation method when the thermometer is when the environment temperature changes, ordering and capillary liquid within the corresponding expansion or contraction, the indication error is then generated. The following two kinds of compensation method can compensate the error. 一个。 Measure the actual temperature bimetal compensation: (1) (2) is suitable for measuring ambient temperature indicator and lead the surrounding environment temperature change consistent b. Catheter compensation suitable for indicator and wire surrounding environment temperature change (independently 1) Indicator of temperature change is very small, around and around the conductor temperature change is large, and vice versa ( 2) Various parts of the wire under different ambient temperature ( 3) Part of the wire is heated 5, protection tube, if appear the following situations, protecting tube should be used to protect the heat ( 1) With anti corrosive fluid, it is necessary to use appropriate material made of protecting tube. ( 2) If there is a high pressure, it is necessary to use to adapt to the working pressure of protecting tube. ( 3) If the fluid flowing, it is necessary to use appropriate flow rate and flow protection tube. ( 4) If draw temperature timing fluid leakage, it is necessary to use the protection tube. ( 5) If the filling liquid leakage from the sensor inside the thermometer, it is necessary to use protection tube.