Which type of manual valve is used to regulate flow rate? Here is my understanding!

Butterfly valves can only be used for opening and closing; control valves, on the other hand, can regulate flow rate and adjust it according to a specific flow curve

A stop valve can only be used for shutting off flow. It cannot be used for adjustment. Regulation involves the continuous adjustment of a liquid based on actual needs; therefore, valves must have functions for temperature and flow control as well as automatic adjustment. Globe valves, on the other hand, lack such positioning capabilities – they cannot adjust their opening degree automatically in response to changes in liquid pressure, so they cannot be used for regulation purposes. Similarly, they cannot be used for throttling, as changes in pressure result in changes in flow rate, and they lack an automatic balancing function. Ball valves are also okay. However, it cannot be used under high pressure, otherwise the soft-sealed PTFE will be eroded by the medium. As for butterfly valves, I’m not entirely sure about that. This post was last edited by qq375170364 on 2009-4-20 at 22:35.]

Globe valves cannot regulate flow; it seems that all other types of valves can do so. Globe valves can only be in either fully open or fully closed position. This post was last edited by qq375170364 on 2009-4-20 at 22:36.]

Ball valves cannot be used for flow regulation, while globe valves can

This gate valve seems to work fine. It is adjusted at the cost of damaging the sealing surface. However, gate valves are used in many places nowadays. Maybe it’s relatively cheap?: Who knows why globe valves can be adjusted. I just checked. . :Q It actually works. . Could someone please answer my question by the way?

In actual production, all the manual valves mentioned above can be used to regulate flow.

Control valves are classified into nine major categories based on their structure: (1) Single-seat control valves； (2) Two-seat control valve ； (3) Sleeve control valve ； (4) Angular adjustment valve ； (5) Three-way control valve ； (6) Diaphragm valve ； (7) Butterfly valve ； (8) Ball valve ； (9) Eccentric rotary valve. The first 6 are linear stroke, and the last 3 are angular stroke. These nine products are also the most basic ones, and are also known as ordinary products, base products, or standard products. Various special and dedicated products are developed as improvements and variations based on these nine categories of products. The following content is optional and can be skipped if you wish; it is provided for reference only: Control valves can be roughly divided into the following 9 major categories based on their structural characteristics: (1) Straight-through single-seat control valves: These valves are the most widely used. They feature minimal leakage, a small allowable pressure difference, a complex flow path, and a simple structure. Therefore, they are suitable for applications where low leakage is required and the working pressure difference is small, with clean media. However, smaller-sized valves (with a nominal diameter of DN < 20 mm) can also be used in situations with higher pressure differences. In the application, attention should be paid to checking the allowable pressure difference to prevent the valve from failing to close properly. (2) Straight-through two-seat control valve: Unlike the straight-through single-seat control valve, it features high leakage and a large allowable pressure difference; therefore, it is suitable for applications with less stringent leakage requirements and high operating pressure differences, involving clean media. When selecting such a valve, it is necessary to ensure that its leakage level meets the requirements of process control. (3) Sleeve valve: Sleeve valves are available in two configurations – single-seal and double-seal. The former is similar to a single-seat valve and is suitable for applications that require a single-seat valve. The latter is similar to a two-seat valve and is suitable for applications where two-seat valves are used. Sleeve valves also feature good stability and ease of installation and removal, but their price is 50％ to 200％ higher than that of single-seat and double-seat valves, and they require special wound sealing gaskets. Sleeve valves are the second most widely used type of valve after single-seat and double-seat valves. (4) Corner valve: Its throttling mechanism is similar to that of a single-seat valve, but the valve body has a simple flow path; it is suitable for applications involving clean media with low leakage requirements and modest pressure differences, as well as in situations where right-angle piping is required. (5) Three-way valve: It has 3 channels and can replace two straight-through single-seat valves; it is used for diverting and combining flows, as well as in applications involving two-phase flows with a temperature difference of no more than 150 °C. When DN≤80 mm, the merging valve can be used in diversion applications. (6) Diaphragm valve: It has a simple flow path, and the diaphragm possesses certain corrosion resistance; it is suitable for two-position on/off control in applications involving dirty or mildly corrosive media. (7) Butterfly valve: It uses a straight pipe section as the valve body, and this valve body also serves as the seat; as a result, it has good self-cleaning properties, along with a smaller size and lower weight. Suitable for dirty media and applications with large diameters, high flow rates, and large pressure differences. When Dn > 300 mm, butterfly valves are usually used for this purpose. (8) Ball valve: An “O”-type ball valve is a non-obstructive valve when fully open, offering the best self-cleaning performance; it is suitable for two-position on/off applications involving particularly dirty media containing fibers. “The V-shaped ball valve features approximately equal percentage control characteristics, making it suitable for use with dirty, fibrous media in applications where significant adjustment is required. Ball valves are relatively expensive. (9) Eccentric rotary valve: This valve lies between butterfly valves and ball valves; it has good \"self-cleaning\" properties, excellent control capabilities, and can also be used for shut-off purposes. Therefore, it is suitable for applications with dirty media and low leakage requirements, although it is relatively expensive. ?Of these 9 types of products, the first 6 are linear stroke control valves, while the last 3 are angular stroke control valves. As users of control valves, it is essential to understand their characteristics and precautions. All types of variant products and improved products evolve from these 9 categories; by understanding these 9 main categories, it becomes easier to grasp the applications of other products

All of them have a regulating function, but the range of regulation and the operating conditions vary. Generally, globe valves and ball valves are used to regulate flow, while others are used for opening and closing.