What is Hose Pinch Valve
Publish Time: 2021-04-22 Origin: Site
The hose pinch valve has applications in many areas of life, especially in industry. It is a type of valve product with rubber sleeves as seals and opening and closing parts. The handwheel drive drives the up and down movement of the upper and lower valves to achieve the opening and closing effect.
4. Hose pinch valve structure classification
8. Application areas of hose pinch valves
9. Causes of hose pinch valve leakage
10. How to repair the hose pinch valve after it is worn out
11. Maintenance of hose pinch valve
1. Definition
The hose pinch valve is a valve with a simple design. It is a direct-acting valve used to start, adjust and stop fluid flow. It uses rubber hoses to control liquids. The hose valve is a system for processing mud, liquids containing a large number of suspended solids, and pneumatic conveying of solids.
The hose pinch valve is a valve head with an elastic valve body. This elastomer valve body can be pushed together by a mechanism or process fluid pressure, or "compression". In most cases, the elastomer is a simple complete bushing lining the entire flow channel and the flange. The bushing isolates all moving parts and the logistics layer. In this way, parts that are not in contact with objects can be made of cheaper materials, such as carbon steel. Because the substance is all contained by the inner liner, this type adds the benefit of not requiring a stuffing box.
2. Working principle
The hose pinch valve is composed of an elastic tube and a hose clamp rod mechanism. The clamping lever mechanism includes a closing stop block to prevent excessive clamping of the tube. Molded rubber hoses are usually installed in metal. The metal body includes a clamping mechanism, which is an elastic tube or sleeve. It may be some kind of mechanical squeezing system until the walls are squeezed or clamped together so that the ports can be completely closed. The differential screw is used to control the two clamping mechanisms to work in a vertical centering to reduce the working stress of the pipeline. By adjusting the fluid pressure, the hose valve can be throttled and closed.
The hose pinch valve is closed by the pressure difference of 2-3bar between the medium pressure/working pressure in the valve body of the hose valve. When the pressure supply is interrupted and the valve body of the hose valve is ventilated, the inner bushing of the hose valve is fully opened due to its resilience. In the pneumatic hose pinch valve, only the inner bushing and two casing covers are located in the medium (in contact with the working medium).
3. Structure introduction
Generally, two common structures of hose pinch valves are the open valve body and closed valve body.
The open-body hose pinch valve does not have a metal valve body shell but relies on a metal skeleton structure. The skeleton structure has two crossbars fastened to the metal flange bracket. The metal flange bracket is designed in two halves so that the rubber bush is placed between the flange brackets during installation. The top and bottom brackets are used to connect the crossbar or half of the flange to make it a structural unit. There are threads on the top bracket to facilitate the matching of the threads on the handwheel. The valve stem has a freely moving joint connected to the moving closing element, which is called a compressor. It is located directly above the bushing. When the handwheel rotates, the compressor moves downward and squeezes the bushing at the lower bracket. The open valve body has a relatively simple structure and does not require expensive metal castings. The main disadvantage of this structure is that exposure of the bushing to the external environment will shorten the life of the bushing.
The closed hose pinch valve has the appearance of most flow-through stop valves. The closed structure is similar to the design of the beginning valve body hose valve. The difference is that the compressor is completely enclosed inside the valve body above the bushing. The valve body can be designed to be cast into the bottom of the outer surface with an integral rod and perpendicular to the logistics layer. It acts as a static closed rod. Another design does not use this integrally cast rod and uses a component called a weir. It presses the full pressure of the bush to the bottom of the jacket and closes the valve. Considering each assembly of the bushing, the jacket is cut into two halves along the centerline of the logistics channel and bolted together. There is no drain on the half of the split body at the bottom of the valve body, it can be used as a model hole. The advantage of using a closed body hose valve is that an external fluid or pressure can be introduced into the housing through a conical joint, helping the bushing to remain open or closed.
4. Hose pinch valve structure classification
1) Double half shaft
There are two parts on the valve plate of the hose pinch valve, one is the transmission device of the upper shaft, and the other is the fixing device of the lower shaft, which is mainly connected by a square shaft. Because it is more complicated and takes a long time to process, it is generally only used for large-scale processing, and it is rarely seen in normal times.
2) The size of the head shaft
This hose pinch valve has a flat shaft passing through the lower end. This positioning ensures the stability and symmetry of the valve plate. However, it is easy to make mistakes when assembling, so the pollution is relatively large. Now it is almost eliminated by the market.
3) Equal diameter flat shaft
The evolution version of the small head shaft is the equal diameter flat shaft. It is very common in this market now, because it is the mainstream form of the hose pinch valve structure.
5. Types of hose pinch valves
According to the structure of the hose pinch valve, it can be divided into offset plate type, vertical plate type, inclined plate type, and lever type. According to the sealing form, it can be divided into two types: relatively sealed type and hard sealed type. The soft seal type generally uses a rubber ring seal, and the hard seal type usually uses a metal ring seal. According to the connection type, the hose pinch valve can be divided into flange connection and wafer connection. According to the transmission mode, it can be divided into manual, gear transmission, pneumatic, hydraulic, and electric.
6. Features
Due to the specific nature of the material, the hose pinch valve has certain requirements for its use environment temperature, which is generally controlled at minus 30 degrees to minus 120 degrees Celsius. The hose valve is a new type of valve made by absorbing the advantages of the same type of products in the same industry. This kind of valve has the following characteristics in the application.
1) The inner tube has high wear resistance and corrosion resistance. It is especially suitable for pipeline transportation control of granular slurry and chemical medium.
2) The tightness is very good. Since the medium flows in the hose, it is completely isolated from the valve body and the opening and closing mechanism, eliminating the phenomenon of running, dripping, and leakage.
3) The structure design is reasonable, the operation is simple, and the maintenance is convenient. Only need to replace the hose, valve body, and other structures during maintenance, which improves the service life of the valve and saves the user's production cost.
4) The hose pinch valve can be configured differently according to different media to meet the needs of different users.
5) The hose valve has rich functions and can replace gate valves, globe valves, regulating valves, etc.
7. Advantages
1) The hose pinch valve can tightly shut off the remaining solids, especially suitable for processing suspended solids.
2) It has good cold resistance and can eliminate freezing and cracking caused by fluid crystallization.
3) With good sealing performance, when the valve is connected to the pipeline, there is no need to add additional sealing gaskets to eliminate unfavorable phenomena such as operation, leakage, falling, and dripping.
4) With a scientific and reasonable structure, the valve body can be used for a long time, and the service life is 4-6 times that of ordinary valves.
8. Application areas of hose pinch valves
Because the hose valve housing, flange, and casing cover can be equipped with a variety of materials according to different industrial industries/applications, including aluminum, steel, stainless steel, plastic (such as POM or PVC), and different elastomers (NR, EPDM, IIR, fluorine rubber, silicone, etc.) inner bushing. Therefore, the hose pinch valve can be used in various applications. Typical industry applications are as follows:
Pneumatic conveying system. It is used to shut down, measure, and control any kind of solid/bulk material.
Vacuum conveying. Used to seal/cut powders, particles, fibers, sheet materials, pellet materials, etc.
Chemical industry. Used for metering/cutting off paints, pigments, additives, fertilizers, etc.
Plastic industry. Used to control, seal and distribute particles, powders, spherical materials, etc.
Ceramic industry. As a shut-off valve for solids, sludge, etc.
Environmental technology. Used to seal wastewater, dust, mud, etc.
Water treatment/sewage treatment plant. As a cut-off and/or regulating valve for lime milk, suspension, etc.
Equipment manufacturing/powder painting. Used for shutting off and metering powder, paint, etc.
Construction/cement industry. As a stop valve for cement, concrete, sand, gravel, gypsum, mortar, etc.
Commercial vehicles. It is used to block the exhaust pipes of various bulk materials.
Silo. As overflow protection of silo components, closing blowpipe, distribution, extraction, etc.
Extractive industries. It is used to cut off and control the transportation of minerals, ore, coal, etc.
Train. As a check valve for feces and greywater in vacuum toilet systems.
Metering and weighing system. Used in additives, dyes, pastes, etc.
Food industry. Measure and cut off feed, barley, pressed residue, sauce, syrup, flavor, spices, flour, salt, sugar, nuts, fruits, vegetables, coffee beans/powder, offal, etc.
9. Causes of hose pinch valve leakage
Hose valves have applications in many areas of life, especially in industry. It is a kind of valve product with rubber sleeves as seals and opening and closing parts, especially in the production industry. When working, the handwheel can be rotated clockwise to achieve the purpose of throttling or even closing. Sometimes the hose valve will leak. At this time, we need to analyze why the hose pinch valve leaks.
1) The hose pinch valve packing is not selected correctly. It is not resistant to the corrosion of the medium, and it is not resistant to the use of high pressure or vacuum, low temperature, and high temperature of the valve.
2) The hose valve packing is not installed correctly. There are defects such as replacing the big with the small, the screw-wound joint is not good, the tightening is loose.
3) The hose pinch valve packing has exceeded the service life, has been aging, and has lost its elasticity.
4) The valve stem of the hose valve has low precision and has defects such as bending, corrosion, and wear.
5) The number of packing turns of the hose valve is insufficient, and the gland is not tightly pressed.
6) The hose valve gland, bolts, and other parts are damaged, making the gland unable to be compressed.
7) Incorrect operation of the hose valve, excessive force, etc.
8) The gland is skewed, and the gap between the gland and the valve stem is too small or too large, causing the valve stem of the hose valve to wear and the packing to damage.
10. How to repair the hose pinch valve after it is worn out
Replace the bushing.
When the hose valve journal is slightly worn, we only need to replace the new bushing. In this way, the shaft clearance can be restored to the specified range.
The inner cavity inserting method.
When the inner cavity of the pump casing and gear teeth of the hose valve are worn, it will cause the pressure of the hose valve to drop and the pump oil volume to decrease. At this time, it is usually repaired by the inner cavity inserting method.
The cross-section is flattened.
When the gear surface of the hose valve is worn, it is usually chosen to grind the section flat, and then use a grinder to decompose the surface of the pump casing to ensure that the end surface gap of the pump remains within the specified range.
11. Maintenance of hose pinch valve
The hose valve is very common in industrial production, but the problem is that its service life is the same as that of general products. It cannot be used for a long time. Because the service life of the hose valve is affected by many factors, it is necessary to have a longer service life. They need to do their maintenance work. The following is an introduction to the method of protecting the hose pinch valve.
1) Pay attention to the storage environment of the valve. It should be stored in a dry and ventilated room, and both ends of the passage should be blocked.
2) The valve of the hose valve should be checked regularly, and the dirt on it should be removed, and anti-rust oil should be applied to its surface.
3) The valve after installation and application should be checked and repaired regularly to ensure its normal operation.
4) Check whether the sealing surface of the valve is worn or not, and repair or replace it according to the situation.
5) Check the wear of the trapezoidal thread of the valve stem and the valve stem nut, whether the packing is out of date and invalid, etc., and replace it if necessary.
6) The sealing performance of the valve should be tested to ensure its performance.
7) The valve in operation should be intact, the bolts on the flange and the bracket are complete, the threads are not damaged, and there is no looseness.
8) If the handwheel is lost, it should be equipped in time and cannot be replaced with an adjustable wrench.
9) The packing gland is not allowed to be skewed or have no pre-tightening gap.
10) If the valve is used in a harsh environment and is easily contaminated by rain, snow, dust, sand, and other dirt, a protective cover should be installed for the valve stem.
11) The ruler on the valve should be complete, accurate and clear, and the valve should be sealed and capped.
12) The insulation jacket should be free of dents and cracks.
13) Avoid hitting the hose pinch valve or supporting heavy objects during operation.
JIANAI Valve Co., Ltd. is top 10 China pinch valve manufacturers. We focus on the production of pinch valves, hose pinch valves, pneumatic pinch valves, pinch valve sleeves, and other products, which are widely used in mining and metallurgy, steel smelting, fine chemicals, and other industries. Welcome to consult and cooperate!