The valve bodies of control valves come in ball valve and globe valve types – what are the differences?

This post was last edited by ylb913 on 2016-10-12 at 22:32. Control valves generally belong to the globe type.

I checked on Baidu; control valves and globe valves look similar in appearance, but their valve cores are different. The valve core of a control valve has been modified so that the degree of opening is directly proportional to the flow rate.

The original poster has misunderstood a concept, namely the difference between control valves and valves with control functions. The statement that the valve bodies of control valves include ball valves and globe valves is incorrect; it should be that valve bodies with control functions include ball valves, globe valves, etc. This misunderstanding might stem from misleading information provided by some manufacturers or from habitual usage in everyday language. There is a specific type of valve called a control valve, whose actuator is of the plunger type, and it can be further divided into single-seat, sleeve, cage, three-way split, three-way combine, etc. In terms of valve classification, control valves are on an equal footing with ball valves, butterfly valves, globe valves, gate valves, etc., rather than being subordinate to them. Valve bodies with control functions can take many forms; it’s just that different types of valve bodies offer varying degrees of control precision and flow characteristics. For electric valves, an actuator designed for control can be used to regulate the valve, while for pneumatic valves, a positioner is needed to achieve regulation. Whether a valve has control functions has nothing to do with its valve body design – it depends on the actuator used. In the case of pneumatic control valves (plunger type), they can also be used as shut-off valves if no positioner is used, though such valves would have a leakage rate corresponding to level 4 according to national standards, and they are generally not used in this manner.

This post was last edited by Think for half a year on 2016-10-10 at 15:25. Thank you, it’s extremely professional. I’m learning *; could you please check if it’s correct? Hand valves such as stop valves and V-ball valves can be used in production to regulate flow, while ordinary ball valves and gate valves are typically designed to remain open or closed. There is also a type of pneumatic or electric valve that has only an open and a closed position; what is that type of valve called? For example, if I want to install a new device, how should I choose the valve?

1. Manual valves such as stop valves and V-ball valves can be used in production to regulate flow, while ordinary ball valves and gate valves are typically designed to remain open or closed at all times. 2. There is also another type of pneumatic or electric valve that has only an open and a closed position – what is that type of valve called? 3. For example, if I want to install a new device, how should I choose the valve? Reply 1: For manual valves, globe valves and V-ball valves can be used to regulate flow. Ball valves and gate valves can also be used for this purpose, though their effectiveness may not be as good. Plunger-type control valves were actually developed specifically for regulation; in terms of both flow control capabilities and precision, they are the best among other types of valves. These valves also come in manual versions. So, do you mean that ordinary ball valves cannot be used for regulating flow? For manual ordinary ball valves, it’s possible to open them a little or halfway, but their adjustment capability is not as good as that of V-ball valves. Therefore, in such applications, it’s generally better to choose V-ball valves rather than ordinary O-ball valves. Reply 2: For valves that are electric or pneumatic and can only be in an open or closed position, it depends on the type of valve body. For example, if it’s an O-type ball valve, then it’s referred to as an electric O-type switch ball valve or electric O-type shut-off ball valve. In the case of butterfly valves, they’re called electric switch butterfly valves or electric shut-off butterfly valves. The method of connection can also be included in the name; this way, many details can be understood from the name itself, which is useful for those working on-site, for technical purposes, for procurement, or for manufacturers. Reply 3: When selecting valves for new equipment, the choice should be based on the operating conditions at the site and the function of the valve. If the valve is intended solely for opening and closing, we first need to determine the type of valve body suitable for those conditions. This can be done by referring to the type of manual valves used in similar situations at the site, or by consulting experienced technicians or providing the relevant operating conditions to the manufacturer so that their technical staff can assist with the selection. It is also necessary to decide whether electric or pneumatic drive will be used. If there are special requirements for the valve, additional accessories may be needed; for example, a pneumatic ball valve typically takes 1–2 seconds to go from fully open to fully closed. If this time seems too fast, a throttle silencer needs to be installed on the cylinder, and this should be mentioned to the manufacturer. Usually, such an accessory isn’t included by default, but specific details can be discussed with the manufacturer by providing information about the operating conditions at the site.