As shown in the figure, the part marked 175mm is the lengthened part. Under the condition of ultra-low temperature, the valve stem and valve body can only be of stuffing box or bellows structure. There are many restrictions on the use of bellows. Generally, the stuffing box seal structure is used. The stuffing box seal structure is simple to process and convenient to maintain. However, its sealing effect cannot be guaranteed when the temperature is less than - 40 ℃. Therefore, ultra-low temperature valves are designed to keep the stuffing box away from materials as far as possible and choose the packing with low temperature characteristics.

The measuring tube is in the magnetic field, and the fluid passes through the center of the sensor. It must be able to bear the working pressure of the fluid medium and the electrostatic shielding effect of the excitation coil on the measuring electrode. Therefore, the material of the measuring tube must be non magnetic, with high resistivity, low thermal conductivity and certain mechanical strength. Generally, stainless steel, glass fiber reinforced plastic Aluminum and other high-strength materials. The measuring pipe here is made of stainless steel