What are the advantages and disadvantages of pressure type thermometer?1

Pressure type thermometer is the use of sealed container of liquid, gas or saturated steam heated volume expansion and pressure changes as the signal. Its basic structure is made up of bulb, capillary and indicator of three parts. It is one of the earliest methods of temperature control applied in the production process. Pressure type temperature measuring system now is still on the instructions and control is widely used in the temperature measurement method. Pressure type thermometer is: the advantages of simple structure, high mechanical strength, is not afraid of vibration. The price is low, does not need external energy. Pressure type thermometer faults is: limited temperature range, generally in - 80~400℃; Heat loss due to slower response time; Instrument sealing system ( Bulb, capillary, spring tube) Damage is difficult to repair, must be replaced. Measuring accuracy are greatly influenced by environmental temperature, temperature package installation location, accuracy is relatively low; Capillary transmission distance limit.