It is a flexible body valve made of a flexible tube that can be pulled in a way or “pinched” mechanically through a mechanism or by applying pressure to the fluid to provide a complete closing of the flow path.
The flow path of the valves is straight and free of gaps or moving components. A soft part of pinch valves is able to close around the solids that are trapped. This makes a pneumatic pinch valve a perfect option to handle slurries, food products as well as pharmaceuticals.
Also known as clamp valves, they are made to regulate or stop the flow of abrasive, fibrous, granular, or high-corrosive media. It finds its wide use as an isolating and controlling valve for sludges, dust, emulsions and powders, gaseous substances, gas, compressed air pellets, and so on.
What is Pneumatic Pinch Valve:
The pneumatic pinch valve is known as a two way valve, which is especially designed for shutting-off or controlling the corrosive and abrasive media. This proportional needle valve uses the pressurized air for opening and closing the valve.
When the valve is in the open position, then the electronic flow control valve has no restriction. And it let the wide range of media to pass through its bore. The flexible internal rubber sleeve is used in the pneumatic valve that keeps the media isolated and prevents the risk of contamination.
Pneumatic pinch valves are ideal for the application with slurries & granular products such as cement, sand, gravel, fiber, carbon, chipping, etc. These pinch valves are cost effective and the best thing about it is that they are easy to use.
Working Principle of a Pinch Valve:
A pneumatic pinch valve consists of three primary components: (i) a housing, (ii) an elastomeric rubber sleeve, and (iii) a connection at the end. The elastomeric tube fits inside the housing from the inlet to the outlet using an adjustable pinch bar mechanism. It is the only part to connect to the flow of media.
The connections at the ends can be bolted, screwed, or threaded on each end to ensure support and a connection. The pinch mechanism could be of a variety of kinds. Simple screw-operated mechanisms that pinch only just one end of the tube or a differential screw equipped with two mechanisms for pinching. Mechanical mechanisms that utilize either hydraulic proportional control valve or air to squeeze the tube may also be employed.
Under normal circumstances, the pinch valve will be in operation. If the hydraulic or air pressure applies to the valve, it pulls down the elastomeric rubber sleeve, creating a pinching effect. If the sleeve has been fully pulled down, the flow becomes reduced, and the valve is shut. The rubber sleeve of a pneumatic pinch valve is able to hold the particles in it, resulting in a superior shut-off.
If the pressure outside is removed by forces of flow media and the rebounding properties of the rubber sleeve, completely let the valve open. The proportional valve is fully open, allows for free flow of the media, and stops the valve from getting blocked. Because the medisolenoid pinch valves come into contact with the tube, it is uncontaminated, which is why there is no risk of contamination.
Pinch valves are one of the following kinds:
Manual Pinch Valve:
Manual Pinch Valves can be operated with a hand wheel, totally opposite to the electric proportional control valve. This hand wheel mechanism triggers the pinch bar(s) to push the sleeves horizontally (centrally dependent on the size of the nominal). This creates a secure seal for your product’s flow.
Furthermore, the direct connection between the sleeve’s inner with the Pinch bar(s) will ensure the best opening for the sleeve in order to allow for full flow. The maximum operating pressure for the hand-operated Pinch Valve is determined by the design and the size and ranges anywhere between three and forty bar.
Air-Operated Pinch Valve:
A Cost-Effective Solution to Flow Control Problems. Air Operated pneumatic pinch valve offer an affordable solution to problems with flow control. The secret lies in the rubber sleeve, which is the sole wet part of the valve. The valve’s action is done through hydraulic pressure or air applied directly to the elastomer sleeves.
The valve body functions as an internal actuator that eliminates the need for expensive pneumatic, hydraulic, or electric motors. The sleeve’s robust flexibility permits the valve to be closed and then drop down around trapped solids. It is generally accepted that 25 psi above the line pressure is needed to ensure full closure of air-operated pinch valves.
Hydraulic Pinch Valve:
A contemporary hydraulic pinch valve is one that makes use of tubes made of elastomer that fold to prevent stretching and increase the lifespan of the valve. It’s among the most popular pinch valves in use today because of its broad range of specifications.
- A hydraulic proportional valve is smaller by 2/3 than the other actuators. It is the ideal option for small areas.
- In-line and fast tube changes using patented tube folds that are durable and self-cleaning.
- Interior and exterior corrosion-resistant
- Incorporates wear sensor.
At the time of selection for the solenoid pinch valves, the manufacturer of the equipment considered which variable type required to be controlled. The pneumatic pressure valve not only helps you in controlling the pressure of the fluids.
But it can also aid the other relevant processes like rotation speed, temperature, position, flow, force. When the OEM has established which variables are needed to be controlled. So, they need to know the other application criteria also for the valves like:
- Required the suitable flow range.
- Media & ambient temperature.
- Inlet pressure along with the maximum controlled outgoing pressure.
- Action required at the time of power loss.
- Power utilization specially for the mobile applications.
- Media types that might influence the required valve materials and construction.
- Other environmental factors like vibration, hazardous location, and space restrictions.
The most critical question is how to adjust the proportional valve and this is dependent on the static or dynamic application.