According to different application requirements and structural features, industrial gas pressure regulators can be classified into the following categories:
Classification by Action Mode
Direct-acting type: High-pressure gas flows in from below the valve disc, tending to open the valve. It usually needs to be matched with a reverse-acting sensing element and is rarely used nowadays.
Reverse-acting type: This is the most mainstream type. High-pressure gas flows in from above the valve disc, tending to close the valve. Its advantages include tighter valve port closure with higher outlet pressure (ensuring excellent sealing performance), smaller spring force required for the same set pressure, and more precise control.
Classification by Structural Form
Diaphragm Type: Uses rubber or metal diaphragms as pressure sensing elements. It features high sensitivity and fast response speed, making it suitable for high-purity gases and corrosive gases. The diaphragm isolates the flow channel from components like springs to prevent contamination, but its pressure-bearing capacity is relatively low.
Piston Type: Adopts metal pistons as pressure sensing elements. It has a robust structure, high pressure-bearing capacity, and good durability, making it suitable for high-pressure and large-flow working conditions (such as nitrogen and air pipeline pressure reduction). However, its sensitivity is slightly lower than that of the diaphragm type, and it is more sensitive to particles in the gas, so a filter may be required.
Classification by Stage
Single-stage pressure regulator: Has a simple structure and is cost-effective. However, its pressure regulation accuracy is greatly affected by changes in inlet pressure (known as the "droop" characteristic). Specifically, the outlet pressure will decrease to a certain extent as the cylinder pressure drops from full to empty. It is suitable for occasions where the requirement for pressure stability is not extremely high.
Two-stage pressure regulator: Internally contains two single-stage pressure regulators connected in series. The first stage pre-reduces the sharply fluctuating high inlet pressure to an intermediate pressure, and the second stage performs fine adjustment to output extremely stable pressure. Its outlet pressure hardly changes with variations in inlet pressure and flow rate. It is suitable for occasions requiring extremely high pressure stability, such as laboratory analytical instruments, laser cutting, and welding. Of course, it also has higher cost and complexity.
