Pinch valves are usually described as a fluid control device that capitalizes on flow path constriction in order to reduce or shut off the passage of a specific material. Most designs created for this valve control contains a highly elastic sleeve or insert towards the valve body that is being constricted or squeezed closed with the use of air pressure or mechanical intervention. Such valve closure method is noted to not just function effectively in controlling clean fluids but it likewise works for slurries that contain high concentrations of suspended solids. This procedure is achieved because the flexible sleeve that this device holds has the capacity of creating a reliable seal that surrounds the trapped substances that can potentially block the other mechanisms of the valve.
Going further, a pinch valve has a metal casing that is furnished with a manual or electrically driven mechanical gate or a feed point of compressed air that is mounted at the top portion of the casing. Positioned inside the casing of the control valve is a very flexible sleeve that aid in structuring the fluid flow passage through the device. Once the valve is activated, the sleeve is slowly squeezed closed towards the centre of its length in order to activate the shut off mechanism for the movement of the fluid.
Understanding the parts of the pinch valves are necessary so that you will be able to know how the mechanism works and each component contribute to the high-purity applications of this device. There a lot of things that you need to look at when purchasing a valve as seen in pinch valve selection guide but to help you learn more about this, the parts are enumerated and explained in the information below.
1. Valve Body
This part is responsible for the pressure boundary of a valve control. It plays an important role for the assembly of the valve because its overall structure holds all the other parts together.
2. Valve Bonnet
The bonnet is commonly known as the cover intended for the opening of the valve. This part is made of the same material as the body and it can be connected to the device by means of a threaded, bolted, or welded joint.
3. Valve Trim
The other internal components of the valve is also called as the trim and this covers the disk, seat, and sleeves that are necessary in guiding the stem. The trim makes it possible for the valve to be controlled in basic motions and positions.
Disk and Seat: The disk functions to provide the capability of allowing and restricting the flow of fluid. Once it is fully closed, system pressure is applied throughout the disk if the outer side is depressurized. On the other hand, seat or seal rings deliver a seating surface for the disk. Seal rings are not categorized as one of the pressure boundary parts because the body already contains a substantial amount of wall thickness that can take pressure from the movement of the fluid.
Stem: This part is responsible for positioning the disk and it can be connected to the device through welded or threaded joint.