Pinch valves are a type of 2/2-way valve used to regulate or completely stop the flow of abrasive, granular, or corrosive materials. It operates using compressed air to either close or open the valve. When open, it provides an unrestricted flow path, making it suitable for handling a variety of media with minimal resistance.The valves used in industries handling fluids such as liquids, gases, or slurries often rely on pinch valves to control the flow. 

Inside the valve is a flexible elastomeric sleeve or tube that works through a squeezing mechanism. When the sleeve gets pinched or compressed, the valve shuts.  When opened, the sleeve gets back to the original shape, facilitating the flow. This pinching mechanism effectively regulates the fluid flow.

Why Choose a Pinch Valve?

Pinch valves are the best choice for slurry control applications due to their simple, yet effective design that allows for reliable handling of abrasive and corrosive materials. The flexible rubber sleeve inside the valve completely isolates the flow media from the mechanical parts, preventing wear and contamination.

This design also ensures a tight shut-off, even with solid-laden fluids. Additionally, pinch valves are low-maintenance and resistant to clogging, making them ideal for demanding slurry operations in industries like mining, wastewater treatment, and chemical processing.

Generally, there are two main types of pinch valves: 

• Manual Pinch Valves 

• Air-Operated Pinch Valves

The pinch valves consist of a body that holds the sleeve and pinching mechanism.

A sleeve or a tube made of rubber or other flexible material and an actuator that can be manual, pneumatic or electric. They are mainly used in industries like food processing, pharmaceuticals, chemical handling, water treatment, where corrosive or abrasive fluids are handled, contain solids or slurries and require a sterile set-up. The key advantages of these valves are that they can be used in handling sensitive fluids, are excellent for abrasive media, are low maintenance, and are good for hygiene.

How Pinch Valves Works?

Pinch valves offer a reliable bidirectional shut-off with zero leakage. Because the tube’s self-clearing flaring motion prevents scaling deposits from forming, the pinch valve will not jam or seat.  The flexible rubber sleeve or tube that gets compressed shut to control the fluid flow. When the valve opens, the sleeve is in its normal posture, allowing fluids to pass freely. Closing the valve involves manual, pneumatic or electric actuators pinching the sleeve from the outside. As the sleeve is squeezed, it collapses inwards, curbing the flow completely.

When the pinch is released, the flexible sleeves move back to their original shape, aiding the fluid flow. One thing to notice is that the fluid (liquids, gases and slurries) never touches the valve body but the inner sleeve alone, which makes it the best to handle corrosive or sterile fluids. 

Types Of Pinch Valves

Pinch valves come in various types, each designed for specific applications and materials. The most common types include open-body pinch valves, enclosed-body pinch valves, and pneumatic pinch valves. Open-body pinch valves are ideal for low-pressure applications and are easy to maintain. Enclosed-body pinch valves provide better protection against external elements, making them suitable for harsher environments.

Pneumatic pinch valves use air pressure to control the flow and are often used in automated systems for handling abrasive or corrosive fluids. Each type offers unique benefits depending on the operating conditions and media being controlled. Let's go through the main types of Pinch Valves:

1. Manual Pinch Valves

Manual Pinch valves are operated by hand, ideal for low-pressure applications. These valves have a main body housing a flexible elastomeric tube through which fluid flows. The mechanical actuator is usually a handwheel or a lever. When the handwheel is turned or the lever is pulled, a bar is pushed down, compressing the sleeve. This pinching closes off the flow path and stops the flow. To let the fluid pass, the operators pull back the lever or turn the handwheel in the opposite direction.

Manual Pinch Valves are simple, straightforward and cost-effective. They are also suitable for abrasive fluid media, as the only part that comes in contact with the moving fluid is the inner sleeve. They are easy to maintain, usually, the part that might need periodic replacements is the inner sleeves.

2. Pneumatic (Air-Operated) Pinch Valves

Air-operated pinch valves set a more automated alternative when compared to the manually operated pinch valves. The body is similar to the manual pinch valves, contains a flexible rubber sleeve inside, instead of manually operated levers, screws or handwheels, these valves use compressed air to control the sleeve movement.

In the absence of air pressure, the sleeve remains open where the fluid medium flows through, and the flow is restrained or blocked when compressed air is introduced and the surrounding sleeve is collapsed inward.

How To Choose a Pinch Valve

When selecting a pinch valve for a specific application, consider the following key factors:

1. Material:
   Choose a valve body made from lightweight materials to ensure ease of installation and handling. Since the media doesn't come into contact with the valve body, compatibility isn't a major concern for that part. However, the sleeve material is crucial, as it is the only part in direct contact with the media. Options for sleeve materials include natural rubber, nitrile (NBR), EPDM, silicone, and food-grade rubber. The sleeve should offer excellent resistance to abrasion to withstand wear from harsh or abrasive media.
2. Pressure Considerations:
   To ensure reliable operation, pressure differentials must be carefully evaluated:

• For Opening: The media or system pressure must exceed the control (actuation) pressure. If this difference is too small, the valve may not open properly. During opening, control pressure is typically 0 bar.
• For Closing: The control pressure must be higher than the system pressure. An insufficient pressure difference may prevent the valve from closing fully.
   

The maximum control pressure can be calculated as:

Max Control Pressure = System Operating Pressure + Maximum Required Pressure Differential

Types of Pinch Valves from Valmet

Flowrox by Valmet offers mainly two types of pinch valves: Let figure out them:

• Flowrox™ heavy-duty pinch valves:

Flowrox PV, PVE and PVE/S heavy-duty pinch valves are specially built for on/off and control applications involving abrasive slurries, powders and granular materials. These valves provide full-bore flow with no restraints when open and ensure reliable bubble-tight shut-off even if solids build up inside. These valves are known for their durability and low maintenance needs. Flowrox valves feature a replaceable rubber sleeve as the only wearing part, significantly cutting spare replacements and downtime.

Technical Specifications:

Features & Benefits

Tailored to meet demanding industrial conditions, these valves can be optimised for enhanced control using conical sleeves and smart positioners. Each Flowrox pinch valve can be accurately sized to operate within an ideal control range, helping reduce wear, improve flow velocity and avoid cavitation issues. To simplify this process, Flowrox offers different valve sizing options. This tool follows the internationally recognised IEC60534 standard, which aligns with the ANSI/ISA S75 guidelines, ensuring reliable and efficient valve performance.

Flowrox provides extra-thick polyurethane (PU) sleeves for high-wear control valve applications. Some of the benefits of Flowrox flow control solutions are:

• Accurate flow control.
• Enhanced productivity and process efficiency
• Usual payback time: as 15 months in on/off applications
• Saving spare part costs
• Reduced downtime costs
• Comprehensive sizing and selection service
• Low-cost maintenance and extended service gaps.

• Flowrox PVG and PVEG pinch valves

These valves are a dependable solution replacing diaphragm valves. Flowrox PVG and PVEG pinch valves are powerful and cost-friendly valves with a simple and single-sided closing mechanism. PVG valve has a strong valve body and opening tags in the sleeve. PVEG valve has a corrosion or abrasion-resistant and light plastic body. Both these valves provide a reliable and robust structure that is proportional to significant cost savings and improved performance. 

Technical Specifications:

Features and Benefits

Flowrox PVG and PVEG valves are ideal for low-cycle applications such as abrasive and aggressive slurries handling. PVG valves offer a 100% tight shut-off even with particles and provide unrestricted flow due to the valve structure. They can be installed easily and quickly. Several dimensions are available: from 50 mm to 250 mm, and are compatible with manual, pneumatic and electrical actuators. PVEG valves have a light body made of a polyamide blend. 

Some of the benefits of PVG and PVEG valves are as follows:

• Simple process and low maintenance cost.
• Easy and hassle-free installations.
•  No flow restriction.
•  Ideal for abrasive and aggressive slurries.
• Long lifetime with low-cost 
• Reliable and trouble-free running.

If you are looking for more products from Flowrox by Valmet in UAE and MENA region, Then Technomax will be your trusted partner.

Get the Best Pinch Valve from Technomax

Technomax, your trusted supplier and the authorised provider of Flowrox by Valmet pinch valves in the UAE, delivers high-performance flow control systems. Pinch valves from Flowrox are suitable for corrosion and abrasion resistance applications and long-lasting performance in industrial settings. Being the leading engineering company in UAE and Middle East, Technomax offers condition monitoring services like vibration analysis, infrared thermography, laser shaft alignment and much more

If you are looking for a right valve solution for your industry in UAE and the Middle East? Look no further! Technomax will be your trusted partner.  Contact us now to get a quote and enjoy the high-quality service!

FAQs

1. What is a pinch valve?
   A pinch valve is a flow control device that uses a flexible tube and compressed air or mechanical force to open or close the flow path. It is ideal for handling abrasive, corrosive, or fibrous media.
2. What is the difference between a pinch valve and a needle valve?
   A pinch valve controls flow by pinching a flexible sleeve, making it suitable for bulk and slurry media. A needle valve, on the other hand, uses a narrow plunger to precisely regulate flow in small volume applications.
3. What is a pinch valve adapter used for?
   A pinch valve adapter is used to connect the valve to compatible piping or equipment, ensuring a secure and leak-free installation. It also helps in aligning and supporting the flexible sleeve during operation.
4. What is the difference between a plug valve and a pinch valve?
   A plug valve uses a cylindrical or conical plug to block or allow flow, making it suitable for high-pressure systems. A pinch valve, in contrast, uses a flexible sleeve pinched shut for low-pressure and abrasive media applications.