• Reduce internal wear rate
• Electrolytic polishing, direct-injection water cleaning and assembly, tested and certified in a clean room.
• With minimal moisture, oxygen and hydrocarbon effects.
• The printed words are marked by laser with permanent hot sticker code.
• Hastelloy® C-22™ and custom special requirements available

Pneumatic valve Uhp valve

Pneumatic valve: a valve actuated by means of compressed air. In the current market economic environment, the practice of only specifying the specifications, categories and working pressure to meet the procurement requirements when purchasing pneumatic valves is not perfect because the manufacturers of pneumatic valves are all under the concept of unified design of pneumatic valves for product competition. Different innovations have formed their own corporate standards and product personality. Therefore, it is very necessary to put forward technical requirements in detail when purchasing pneumatic valves, and coordinate with manufacturers to reach a consensus as an accessory of the pneumatic valve purchase contract.

Purpose/Pneumatic Valve

It is a right-angle rotary structure. It can be used together with a valve positioner to realize proportional adjustment. The V-shaped spool is most suitable for various adjustment occasions. It has large rated flow coefficient, large adjustable ratio, good sealing effect, sensitive adjustment performance and volume. Small, can be installed vertically. Suitable for controlling gas, steam, liquid and other media.

It is a right-angle rotation structure, consisting of a V-shaped valve body, a pneumatic actuator, a positioner and other accessories; it has an inherent flow characteristic of approximately equal percentage; it adopts a double bearing structure, with small starting torque and excellent sensitivity and induction. Speed; super shearing capacity.

Working Principle/Pneumatic Valve

The pneumatic piston actuator uses compressed air as the power source, and drives the crank arm to rotate 90 degrees through the movement of the piston to automatically open and close the valve. Its components are: adjusting bolt, actuator box, crank arm, cylinder block, cylinder shaft, piston, connecting rod, universal shaft.

The working principle of the pneumatic control valve: the pneumatic control valve is composed of an actuator and a regulating mechanism. The actuator is the thrust component of the regulating valve, which generates corresponding thrust according to the size of the control signal pressure, and pushes the regulating mechanism to act. The valve body is the regulating part of the pneumatic regulating valve, which is in direct contact with the regulating medium to regulate the flow of the fluid.

Classification/Pneumatic Valve

First, the main types of pneumatic valves:

1) Pneumatic V-shaped regulating ball valve

2) Pneumatic O-type shut-off ball valve

3) Torque type cylinder ball valve

4) Electromagnetic diaphragm valve moving picture

5) Pneumatic straight stroke diaphragm valve

2. Pneumatic V-type regulating valve

Material/Pneumatic valveedit

Body Material

Ductile iron should be the main material, and the grade and actual physical and chemical testing data of the cast iron should be indicated.

Stem material

Strive for stainless steel stem (2CR13), and large-diameter valves should also be stainless steel embedded stems.

Nut material

It adopts cast aluminum brass or cast aluminum bronze, and its hardness and strength are greater than that of the valve stem.

Stem Bushing Material

Its hardness and strength should not be greater than that of the valve stem, and it should not form electrochemical corrosion with the valve stem and valve body under the condition of water immersion.

Material of sealing surface

①The types of pneumatic valves are different, and the sealing methods and material requirements are different;

② For ordinary wedge gate valves, the material, fixing method and grinding method of the copper ring should be explained;

③Physicochemical and hygienic testing data of soft sealing gate valve and valve plate rubber lining material;

④Butterfly valves should be marked with the material of the sealing surface on the valve body and the material of the sealing surface on the butterfly plate; their physical and chemical testing data, especially the hygienic requirements, anti-aging performance and wear resistance of rubber; usually nitrile rubber and EPDM are used. Rubber, etc., it is strictly forbidden to mix reclaimed rubber.

valve shaft packing

①Because the pneumatic valves in the pipe network are usually opened and closed infrequently, the packing is required to be inactive for several years, and the packing will not age, so that the sealing effect can be maintained for a long time;

②The valve shaft packing should also have good sealing effect when it is subjected to frequent opening and closing;

③ In view of the above requirements, the valve shaft packing shall not be replaced for life or more than ten years;

④ If the packing needs to be replaced, the design of the pneumatic valve should consider the measures to be replaced under the condition of water pressure.

Operation method/Pneumatic valve

1. The opening and closing direction of the pneumatic valve should always be closed clockwise.

2. Since the pneumatic valves in the pipe network are often opened and closed manually, the opening and closing revolutions should not be too many, even large-diameter valves should be within 200-600 revolutions.

3. In order to facilitate the opening and closing operation of one person, the maximum opening and closing torque should be 240N-m under the condition of pipeline work pressure.

4. The opening and closing operation end of the pneumatic valve should be a square tenon with standardized dimensions and face the ground, so that people can directly operate it from the ground. Valves with discs are not suitable for underground pipe networks.

5. Display panel for opening and closing degree of pneumatic valve

① The scale line of the opening and closing degree of the pneumatic valve should be cast on the gearbox cover or on the casing of the display panel after changing the direction, all facing the ground, and the scale line should be brushed with fluorescent powder to show eye-catching;

②The material of the indicator dial needle can be made of stainless steel plate if the management is good, otherwise it is a painted steel plate, do not use aluminum skin;

③ The indicator dial needle is eye-catching and firmly fixed. Once the opening and closing adjustment is accurate, it should be locked with rivets.

6. If the pneumatic valve is buried deep, and the distance between the operating mechanism and the display panel is ≥1.5m from the ground, there should be an extension rod facility, and it should be fixed firmly so that people can observe and operate from the ground. That is to say, the valve opening and closing operation in the pipeline network is not suitable for downhole operation.

Routine Maintenance/Pneumatic Valves

1. The inside and outside of the valve body (including the variable speed transmission box) should first be shot blasted to remove rust and sand, and strive to electrostatically spray powder non-toxic epoxy resin with a thickness of more than 0.3mm. When it is difficult to electrostatically spray non-toxic epoxy resin for extra-large valves, similar non-toxic epoxy paint should also be brushed and sprayed.

2. The inside of the valve body and all parts of the valve plate require comprehensive anti-corrosion. On the one hand, it will not corrode when immersed in water, and there will be no electrochemical corrosion between the two metals; on the other hand, the surface is smooth to reduce the water resistance. 6.3 The hygienic requirements of epoxy resin or paint for anti-corrosion in the valve body should have a test report from the corresponding authority. The chemical and physical properties should also meet the relevant requirements.

Packaging and Shipping / Pneumatic Valves

1. Lightweight blocking plates should be installed on both sides of the valve to seal.

2. Medium and small diameter valves should be bundled with straw ropes and transported in containers.

3. Large-diameter valves are also packed in solid wood frame to avoid damage during transportation.

General Requirements / Pneumatic Valves

General requirements

1. The specifications and categories of pneumatic valves should meet the requirements of pipeline design files.

2. The model of the pneumatic valve should indicate the requirements of the national standard number. If it is an enterprise standard, the relevant description of the model should be indicated.

3. The working pressure of the pneumatic valve is required to be greater than or equal to the working pressure of the pipeline. On the premise of not affecting the price, the working pressure that the valve can withstand should be greater than the actual working pressure of the pipeline; any side of the pneumatic valve should be able to withstand 1.1 times when the valve is closed. Valve working pressure value without leakage; when the valve is open, the valve body should be able to withstand twice the valve working pressure requirement.

4. For the manufacturing standard of pneumatic valve, the national standard number should be stated. If it is an enterprise standard, the enterprise file should be attached to the purchase contract. Pneumatic valve standards are divided into three specifications: national standard, American standard and Japanese standard.

5. The complete description of the pneumatic valve includes its size, material, connection method, and action mode (the action mode is divided into 1: double-acting, 2: single-acting).

performance requirements

1. When a valve is manufactured in batches of a certain specification, an authoritative organization should be entrusted to carry out the following performance tests:

①The opening and closing torque of the valve under working pressure;

② Under the condition of working pressure, the continuous opening and closing times of the valve can be guaranteed to be tightly closed;

③ Detection of the flow resistance coefficient of the valve under the condition of pipeline water delivery.

2. The valve should be tested as follows before leaving the factory:

① When the valve is open, the valve body should be subjected to an internal pressure test twice the working pressure value of the valve;

②When the valve is closed, the two sides are respectively subjected to 1.1 times the working pressure value of the valve, and there is no leakage; but the leakage value of the metal-sealed butterfly valve is not greater than the relevant requirements.

Standard Summary / Pneumatic Valves

Standard number Standard Chinese name Standard English name

Review Rubber Seals for Pneumatic Valves Groove Dimensions and Tolerances

Review Rubber Seals for Pneumatic Valves Dimensional Series and Tolerances

ANSI/NFPA T 3.21.4 R2-2000 Pneumatic Valves. NFPA/T 2.6.1 R2-2000 Supplement: Hydraulic Element Pressure Ratings. Pneumatic for Testing Fatigue and Determining Pressure of Hydro-pneumatic Valves Containing Metal Housings valve – Pressure rating supplement to NFPA/T2.6.1 R2-2000, Fluid power components – Method for verifying the fatigue establishing the burst pressure ratings of the pressure containing envelope of a metal fluid power pneumatic valve

BS 4151-1967 Method of evaluating pneumatic valve positioners with input signal of 3 to 151b/in pressure gauges

Parameter Definition/Pneumatic Valve

Nominal diameter

Nominal diameter (nominal diameter), also known as mean outside diameter (mean outside diameter), represents the symbol DN, which is the general diameter of various pipes and pipeline accessories. Pipes and pipeline accessories of the same nominal diameter can be connected to each other and are interchangeable. It is not the outer diameter or inner diameter of the pipe in the actual sense, although its value is close to or equal to the inner diameter of the pipe, in order to make the connection size of the pipe and pipe fittings Unified, using the nominal diameter (also known as nominal diameter, nominal diameter). For example, welded steel pipes can be divided into thin-walled steel pipes, ordinary steel pipes and thickened steel pipes according to thickness. Its nominal diameter is neither the outer diameter nor the inner diameter, but a nominal size that approximates the inner diameter of ordinary steel pipes. Each nominal diameter corresponds to an outer diameter, and its inner diameter varies with thickness. The nominal diameter can be expressed in metric mm or in imperial in. Pipeline accessories are also expressed by nominal diameter, which is the same as seamed pipe.

Nominal pressure

Nominal pressure (Nominal pressure) indicates the symbol PN, the maximum working pressure allowed when applied at a certain temperature. For the control valve with carbon steel body, it refers to the maximum allowable working pressure when applied below 200°C; for cast iron valve body, it refers to the maximum allowable working pressure when applied below 120°C; for the control valve with stainless steel body, it refers to below 250°C Maximum allowable working pressure when applied. When the working temperature increases, the pressure resistance of the valve body will decrease. For example, a carbon steel control valve with a nominal pressure of 6.4MPa (PN64) has a withstand pressure of 5.2MPa when used at 300°C, 4.1MPa when used at 400°C, and 2.9MPa when used at 450°C. . Therefore, the determination of the nominal pressure of the control valve should not only be based on the maximum working pressure, but also according to the maximum working temperature and material characteristics, not only the nominal pressure is greater than the working pressure.