Regulating Valve(Control valve) Forms: Nine Categories of Regulating Valves (Control valves)

Article Summary: Regulating Valves (Control valves) are classified into nine categories based on their structures: single-seat regulating valve, double-seat regulating valve, sleeve regulating valve, angle regulating valve, three-way regulating valve, diaphragm valve, butterfly valve, ball valve, and eccentric rotary valve. The first six are linear stroke, while the latter three are angular stroke. These nine are the most basic products, also known as common products, basic products, or standard products. Various special and custom products are developed based on these nine categories.

Below, the Instrumentation Engineering Network provides a brief introduction to the nine categories of Regulating Valves (Control valves):

Straight-through single-seat control valve: Widely used, with features of low leakage, small allowable pressure difference, complex flow path, and simple structure. Suitable for clean media occasions with strict leakage and low working pressure difference requirements. However, small-sized valves (nominal diameter DN < 20mm) can also be used in occasions with large pressure differences. Pay attention to checking the allowable pressure difference to prevent the valve from not closing tightly.

Straight-through double-seat control valve: In contrast to the straight-through single-seat control valve, it has the characteristics of large leakage and large allowable pressure difference. Therefore, it is suitable for clean media occasions with less strict leakage requirements and large working pressure differences. When selecting, pay attention to whether the valve's leakage meets the process control requirements.

Sleeve valve: The sleeve valve is divided into single-sealed and double-sealed structures. The former is similar to a single-seat valve and is suitable for single-seat valve occasions, while the latter is similar to a double-seat valve and is suitable for double-seat valve occasions. The sleeve valve has the advantages of good stability and easy disassembly and assembly, but it is 50%-200% more expensive than single-seat and double-seat valves, and it requires a special wrapped sealing gasket. The sleeve valve is widely used and is the second most widely used valve after single-seat and double-seat valves.

Angle valve: The throttling form is similar to a single-seat valve, but the valve body flow path is simple. Suitable for clean media occasions with low leakage and not large pressure differences, as well as occasions requiring right-angle piping.

Three-way valve: It has three passages and can replace two straight-through single-seat valves. Used for splitting and merging, as well as two-phase flow and occasions with a temperature difference not exceeding 150°C. When DN ≤ 80mm, the merging valve can be used for splitting occasions.

Diaphragm valve: Simple flow path, the diaphragm has certain corrosion resistance. Suitable for occasions with unclean media and weakly corrosive media where two-position shut-off is required.

Butterfly valve: It is equivalent to taking a straight pipe section as the valve body, and the valve body is equivalent to the valve seat. Therefore, it has good "self-cleaning" performance and is relatively lightweight. Suitable for unclean media and large-diameter, high-flow, and high-pressure difference occasions. When DN > 300mm, it is usually completed by a butterfly valve.

Ball valve: The "O"-shaped ball valve is an unobstructed valve when fully open, with the best "self-cleaning" performance. Suitable for occasions with particularly unclean media and fiber-containing media where two-position shut-off is required. The "V"-shaped ball valve has a nearly equal percentage control characteristic and is suitable for control occasions with unclean, fiber-containing media and a relatively large adjustable range.

Eccentric rotary valve: This valve is between a butterfly valve and a ball valve, with good "self-cleaning" and control performance, and can also be shut off. Therefore, it is suitable for adjusting occasions with unclean media and low leakage requirements."

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