Diaphragm Valve Structural classification PP Diaphragm Valve Major parts CPVC Diaphragm Valve Install attention

The diaphragm valve is a special form of interception valve, its opening and closing part is a piece of diaphragm made of soft material, it separates the valve body internal cavity from the valve cap internal cavity. Diaphragm valve is actually a "clamp" valve, a flexible, disturbing diaphragm, bolted to the compression, compression is moved by the valve stem, when the compression rises, the diaphragm is raised, causing access, when the compression drops, the diaphragm on the valve body weir (if weir valve) or at the bottom of the profile (if direct), diaphragm valve is suitable for switching and throttling.

Structural classification: The PP diaphragm valve can be divided into roof, DC, stop, direct, gate and rectangular; it is usually flange connected; manual, electric and pneumatic, and pneumatic drive is divided into normally open, normally closed and reciprocating. 

Right Angle, Also known as the protruding edge type, is the most basic of a common code name is (G41). The structure is shown in the figure below. The valve body is lined from the figure. Diaphragm valve body lining, is to better play its corrosion resistance characteristics. Such structures, in addition to straight through, can be made into right Angle.

Roof type: Its structure shape is similar to the stop valve, this form of diaphragm valve, fluid resistance than the right Angle diaphragm valve is larger, but large sealing area, good sealing performance, can be suitable for high vacuum pipe.

Direct type. Its structure form is similar to the gate valve The gate-type diaphragm valve has the least fluid resistance, which is suitable for the delivery of sticky materials.

Diaphragm materials are commonly used as natural rubber, neoprene rubber, butyl-based rubber, butyl fine rubber, isoprene rubber, fluorinated rubber and polyfluoroethylene propylene plastic (F46). The disadvantage of the diaphragm valve is that the pressure resistance is not high, generally within 6kgf/cm2(0.6MPa); the temperature resistance is also limited by the diaphragm, generally can only withstand 60~80℃, the highest (fluorinated rubber) does not exceed 180℃.

Installation maintenance: Before installation, the ① CPVC diaphragm valve should be carefully checked whether the operating conditions of the pipeline match the service range specified in the valve, and the inner cavity should be cleaned to prevent dirt jamming or damage to the sealing parts. The ② rubber lining layer and the rubber diaphragm surface should not be painted with grease items to prevent the rubber swelling and affect the service life of the diaphragm valve. The ③ hand wheel or transmission mechanism is not allowed for lifting, and the collision is strictly prohibited. The ④ manually operates the diaphragm valve without using the auxiliary lever to prevent damage to the driving part or the seal due to excessive tightness. The ⑤ diaphragm valve shall be stored in a dry and ventilated room, and stacking is strictly prohibited. The two ends of the stock diaphragm valve must be sealed, and the opening and closing parts shall be in a slightly open state.

High performance valve type: high performance without spring diaphragm valve 1.316L VIM-VAR stainless steel valve body; 2. Suitable for high-purity applications; 3.Elgiloy material diaphragm, high strength and corrosion resistance, long service life; 4. Fully closed PCTFE valve seat design has superior anti-expansion and pollution resistance; 5. Ultra-high purity process specification; 6. Electropolishing of contact surface with media, with an average roughness Ra of 0.13 m 7. The maximum leakage rate of helium gas leakage test is 1 10 std cm / s 8. Low pressure and high pressure two valve types; 9. Manual and pneumatic actuators; 10. Aluminum piston speeds up the switching speed of the valve; 11. Multiple handle forms and colors. High-performance all-metal diaphragm valve 1. All-metal shell, without filler;2. Repetitable closure with fully surrounded valve stem tips; 3. Pressure from vacuum to 3500 psig (241 bar); 4. Temperature is from-100 to 250 F (-73 to 121 C); 5. -9 power std cm / s with a maximum leakage rate of 4x10; 6. Round handle, from full open to close requirements of about one and two half circle; 7. Bar handle, only turn the handle in a quarter circle from full open to close.

Major parts: There are many parts and materials of the diaphragm valve, including a variety of different brands of ferrous metal and nonferrous metals and their alloys, a variety of non-metallic materials. The material for manufacturing the diaphragm valve parts shall be selected according to the following factors: 1. Industrial and mining conditions (the pressure, temperature and characteristics of the working medium). 2. The force situation of the part and its role in the diaphragm valve structure. 3. Good craftsmanship. 4. If the above conditions are met, the cost should be lower. Valve body, bonnet and valve plate (valve valve) material: valve body, valve cover and valve valve are one of the main parts of diaphragm valve, directly withstand the medium pressure, the material used must meet the "pressure and temperature grade of diaphragm valve" provisions.

Install attention: 1 Applicable safety specifications must be followed. 2 The pipe shall be free of impurities before the valve is installed, otherwise it will cause damage to the valve. 3. Connect the valve and pay attention to align the pipe. 4 All valves must be removed from the actuator before welding on the valve body.5. When replacing the diaphragm, keep the diaphragm connected with the sealing surface, and then separate the diaphragm from the sealing surface.

For the air-opening function valve: 1) Ventiate the actuator, lift the diaphragm, and leave the sealing surface. 2) Cross over and remove the four screws on the valve body to separate the actuator from the valve seat, cut off the air source, and replace the diaphragm. 3) Ventiate the actuator and fold up the diaphragm. 4) Face the seal on the diaphragm and the valve seat, cross install the fixing screws, and conduct repeated ventilation several times. 5) After closing the diaphragm valve for leakage test, it can be used normally.

For the air-closure function valve: 1) Cut off the actuator air source, lift the diaphragm, and remove the sealing surface. 2) Cross and remove the screws on the valve body to separate the actuator from the valve seat, vent, and replace the diaphragm. 3) Face the seal between the diaphragm and the valve seat when the diaphragm is folded up, and cross-install the fixing screws. 5) Repeated ventilation activities for several times, close the diaphragm valve leakage test, can be used normally.

For the dual-motion function valve: 1) Cut off the air source, lift the diaphragm, and separate from the sealing surface. 2) Cross-remove the four screws on the valve body to separate the actuator from the valve seat, cut off the air source of the lower cylinder, fill the upper cylinder, and replace the diaphragm. 3) Inflatate the lower cylinder and pack up the diaphragm. 4) Face the seal on the diaphragm and the valve seat, cross install the fixing screws, and repeated ventilation several times. 5) After closing the diaphragm valve for leakage test, it can be used normally.