Pinch valve

Pinch valve

Pinch valve (pinchvalve), also known as pinch valve, air bag valve, hoop valve, etc. in China. The sleeve is the most important part of any pinch valve and is the heart of the pinch valve, providing resistance to corrosion, wear and pressure. The quality of the pinch valve depends on the quality of the casing. Squeeze the casing by pneumatic, electric, manual or hydraulic driving methods to achieve the function of switch/adjustment.

Pinch valve working principle diagram:

Features

1. Unobstructed flow channel, full diameter

4. When there are residual particles, it can still be closed with zero leakage

5. No clearance and dead angle hinder valve operation

7. Simple design, not affected by harsh external environment

Scope of use

In contemporary industry, when some solid or liquid products containing abrasive substances such as particles, powders, fibers, and mucilage are often transported through pipelines, or some chemical processes contain corrosive media, pinch valves are the best choice. .

Sewage Treatment Plant (Sludge Treatment, Gravel Cleaning, Raw Sewage, Lime, Charcoal Sludge)

Power plant (fgd system, ash removal system, coal transportation)

Mining (tailings, flotation control, sludge discharge lines, tailings filling, various other slurries)

Chemical processes (corrosive and abrasive media, powders, granules)

And many fields such as paper mills, pulp mills, electronics industry, food industry, cement, sand, glass and industrial sewage treatment plants.

History and Current Situation

In 1953, the American Red Valve Company invented and manufactured the pinch valve (pinchvalve), using materials provided by world-class suppliers such as DuPont (dupont), Firestone (firestone), Goodyear (goodyear), etc. The perfect combination of rubber synthesis technology and synthetic fiber technology has begun to promote this highly wear-resistant, zero-failure valve product to the market.

American Red Valve has created the only valve that can stably control the slime for the world’s first slime pipeline.

Today, the customer service network of American Red Valve has spread to 175 cities in 75 countries around the world.

The pinch valve (pinchvalve) has entered China in recent years. From unfamiliar to gradual acceptance, this kind of valve with high cost performance and can withstand harsh environments has been widely used in China. There are not many well-known manufacturers of pinch valves in the world. Nowadays, there are American redvalve (redvalve), Finland flowrox (original larox, renamed flowrox in 2012), German ako, etc. that can be purchased and sold in China. Redvalve has set up offices in China.

What followed was a domestic attempt at imitation. At present, many large and small manufacturers in China have launched pinch valves, which quickly occupied some markets with ultra-low prices, which brought some misunderstandings to users who have just come into contact with such valves, such as: the service life of the pinch valve is too short , Usually the tube sleeve is broken in a few months, or even in a month, and the rubber technology mastered is not enough to produce a rubber tube sleeve with high wear resistance, high corrosion resistance and long life. According to research, the earlier batch is still there. Even the more common imported pinch valves have a much longer average service life than domestic ones. Of course, in recent years, domestic pinch valve manufacturers have continuously improved the quality of their products, and the quality difference is no longer so obvious. Many good pinch valve manufacturers have also emerged in China, such as Wuhu Naide, Wenzhou Xiangsong, Shanghai Fengchi, etc. Manufacturers are suitable for large domestic mining and chemical groups, and the cost performance has gradually surpassed the same kind of valves abroad.

Classification

Pinch valves can be divided into two categories: switch type and adjustment type according to their functions.

According to the driving method, it can be divided into:

structure and variety

The rubber sleeve of the pinch valve is the core component, which usually consists of an inner layer, an outer layer and reinforcing fibers. Formed by a primary vulcanization/secondary vulcanization process.

Several companies with a long history have their own characteristics. American red valve holds many advanced casing patents, larox has many years of mining equipment manufacturing background, ako adheres to the style of German industrial standardization and refinement, and so on.

The types of casings of the pinch valve can be divided into: standard casing, thickened casing, high pressure casing, tapered casing, etc. There are many classifications by material, the common ones are: natural rubber, fluororubber, neoprene, Hypalon, EPDM, nitrile rubber, food-grade rubber, chlorobutyl rubber, etc., about twenty or thirty kinds.

insufficient

1. Pinch valves are mainly used in medium and low pressure environments, generally lower than pn16. Only a few companies in the world can manufacture high pressure pinch valves.

2. Because the pinch valve is a valve with a rubber sleeve as the core, the operating temperature is limited, usually within -40~200℃.

3. Limited by the rubber process, on the premise of satisfying the quality and strength of the casing, the manufacturing diameter of the pinch valve is usually within dn300mm. Large-diameter pinch valves are relatively expensive, and there are very few manufacturers that can manufacture them. At present, the larger diameter pinch valve used in the world is the dn1800mm pneumatic pinch valve manufactured by American Red Valve, which is used in the Indianapolis municipal project in the United States.

Selection guide

The parameters provided by the user for automatic pinch valve selection are as follows:

1) Nominal diameter of pipe

2) Working pressure, working temperature

3) Casing material (as specified by the owner or designer)

Including: the composition of the medium, the particle size, especially the composition of the corrosive chemical substances, which is required when selecting the casing material.

6) On-site air source pressure

7) Closing/opening time requirements (if any)

8) Whether there is a valve position feedback requirement

In addition to the above basic conditions, it is also necessary to provide

1) Flow (larger/smaller) –

the range of flow control

2) Pre-valve pressure at larger/smaller flow rates

3) Back-valve pressure at larger/smaller flow rates

Manual valves can be selected as long as they have basic information (pressure, medium, temperature). The more complete the conditions of automatic valves, the better, and the more accurate the selection.