From the perspective of use and safety, the main features of regulating valve are
1. Within the allowable temperature range, it has better thermal stability, less coking and longer service life.
2. Within the allowable temperature range, the thermal conductivity, fluidity and pumping performance are good.
3. Low toxic, tasteless and non corrosive equipment, which has little impact on the environment.
4. The freezing point is low, the boiling point is high, and the content of low boiling point components is small. Within the allowable temperature range, the vapor pressure is not high and the evaporation loss is small.
5. When the temperature is higher than 70 ℃, it will be strongly oxidized when contacting with the air. The heated working system needs to be sealed, but it can only contact with the air below 70 ℃.
6. The volume expands significantly after heating, and the expansion rate is far greater than that of water. With the temperature rising by 100 ℃, the volume expansion rate can reach 8% - 10%.
7. Cracking or condensation may occur in case of overheating, coking or carbon deposition in vessels and pipes.
8. When mixing water or low boiling components, the vapor pressure will increase significantly after heating.
9. The flash point, ignition point and spontaneous ignition point are very high, and will not ignite and burn under the allowable temperature and airtight state.
10. According to the user's living area and the working environment of the equipment, it is recommended to select heat transfer oil suitable for low temperature use. Nowadays, under many working conditions, heat transfer oil is used for heating during production. This often ignores that the continuous adjustment of the ordinary packing seal control valve during use will lead to frequent wear of the control valve packing, and the heat transfer oil will leak out of the packing. Bellows sealing will eliminate this problem. Bellows are more durable than packing, so there is no need to change the packing frequently. The bellows seal is more important for selecting the bellows seal of toxic and harmful gases.
