Points to note when selecting the internal structure of a pipe clamp valve

A sleeve valve, also known as a hose valve, consists of a metal valve body, an internal frame, an inner hose, and an actuator (as shown in the figure below).

After the valve is installed in the pipeline, the hose is used to withstand the scouring and corrosion of the medium. Therefore, problems such as wear resistance and corrosion resistance can be solved at a very economical price.
Different hose materials can be selected for different working conditions. For example, natural rubber (red rubber) can be used for wear-resistant slurry working conditions; EPDM rubber can be used for corrosion-resistant working conditions. This type of valve usually operates at normal temperature and pressure.
When selecting different operating methods, due to the different internal frames, the internal frame needs to be selected according to different operating methods and requirements.
There are two common internal frame structures, see Figures A and B below.

Structure A: The valve stem and the middle clamp move as one, driving the pressure rod to move up and down, changing the flow area of the hose to achieve the purpose of shutoff or flow regulation.
Structure B: The coarse valve cover has internal threads connected to the fine valve stem, and the fine valve stem and the upper pressure rod are integrated. By rotating the coarse valve stem, the fine valve stem moves up and down, and the upper pressure rod moves with it, changing the flow area of the hose to achieve the purpose of shutoff or flow regulation. In this picture, the fine valve stem and the upper pressure rod are welded together. There are other forms of connection, such as pin connection.

For structure A, since the valve stem, clamp, and upper push rod are integrated, when the valve stem is lifted, the entire frame structure deforms, and the main stress is distributed at the ends of the two side brackets. Relative displacement does not occur between the clamp and the push rod, and the valve stem and the clamp, and the overall stability is high, so it can be used for electric and pneumatic operation.

For structure B, since the fine valve stem needs to be fixed to the upper pressure rod, and the coarse valve stem needs to cooperate with the fine valve stem, all the stress during the opening and closing process is borne by the fine valve stem. Once the cooperation between the coarse valve stem and the fine valve stem fails, or the cooperation between the fine valve stem and the push rod fails, relative displacement will occur between the components. From the outside, the valve opening is unstable, as if it is "jumping". Due to this structure is more fragile, it is commonly used for manual operation.

Case Analysis:
Shandong Jinxi Tai Ore Dressing Plant Automation Transformation Project
DN200 Electric Regulating Sleeve Valve

The valve body in the photo uses structure B described above.
However, due to the large valve diameter, the fine valve stem structure is omitted, and the coarse valve stem is directly connected to the push rod.
The two are connected by a pin.
The pin at this location fell off on site, resulting in the customer feedback:
The valve can operate stably when fully open. When the opening is adjusted to 40% or less, jumping occurs, and the opening cannot be further reduced.
Later, our company replaced it with a valve body with structure A frame to avoid the recurrence of this type of fault.