Overview of Industrial Pneumatic Diaphragm Valve Products

Material: WCB

Structural form: DC type

Applicable medium: weak acid-base medium

Standard: National Standard

Flow direction: bidirectional

Parts and accessories: Handwheel

Purpose: As of

Type (channel position): Binary formula

Connection type: flange

Nominal diameter: 100 (mm) mm

Drive mode: manual. Pressure environment: atmospheric pressure. Working temperature: room temperature

The diaphragm valve G41F-16C has a different structure and working principle from conventional valves. It is a self operated structure and does not require external power air supply. Its work is completed through the process medium (compressed air). Compressed air enters the diaphragm valve chamber through a throttling small hole. In the static state, the inlet pressure of compressed air is equal to the air pressure inside the diaphragm valve chamber. The diaphragm valve closes under the action of spring force and does not blow back. Once the discharge is charged, the gas in the gas chamber is released through the discharge port, the pressure drops, the diaphragm valve is automatically opened, and compressed air enters the filter for back blowing. After the discharge solenoid valve loses power, the balance is re established in the gas chamber and the diaphragm valve is closed.

　　Diaphragm valve is one of the earliest regulating valves, which has the following usage characteristics:

(1) The soft rubber diaphragm valve can cut off the medium without leakage.

(2) Due to the certain corrosion resistance of rubber, there were no better corrosion-resistant materials before the 1960s. It was usually promoted and applied as a corrosion-resistant material, and even continues to this day.

(3) The flow path is simple and has a "self-cleaning" effect, which can be used for unclean media.

(4) When used as a corrosion-resistant regulating valve, the front part of the quick opening characteristic can only be used due to its short effective stroke and poor regulating quality.

(5) Like a fatigue test piece, forcing it to fold up and down is prone to damage because the diaphragm is an unreliable component, resulting in a shorter valve life, which is a fatal disadvantage. For this reason, the author has been emphasizing in recent years that diaphragm valves should be phased out and replaced with ball valves and fully functional ultra light valves.

(6) When closed, the force of the medium pushes the diaphragm upwards, resulting in a large unbalanced force and requiring a large actuator thrust. Therefore, a particularly large, bulky, and heavy actuator must be selected to make the valve very heavy, which is twice that of a ball valve and 3-4 times that of a fully functional ultra light valve.

(7) It is particularly important to emphasize that there are more and more corrosion-resistant materials, especially in the late 1980s when the fluorine lined plastic process was solved and fluorine lined ball valves were introduced. Due to the fact that fluoroplastics are more corrosion-resistant and temperature resistant than rubber, and the ball core of a ball valve is ten or a hundred times more rigid than the diaphragm of a stainless steel diaphragm valve, it is recommended to avoid using diaphragm valves as much as possible in situations where corrosive media are cut off and regulated. Instead, corrosion-resistant fluorine lined ball valves, butterfly valves, and fully PTFE single seat valves should be used.

Let's give an example to illustrate: 10 years ago, both foreign and domestic devices used fluorine lined diaphragm valves for valves used in desalination water systems. Their service life ranges from about one year to as short as 3-6 months. Therefore, the diaphragm is constantly being replaced. After selecting a water treatment specific ball valve, this problem was well solved, with a lifespan of up to 7-8 years, and it can generally be used for 3-5 years.

　　Characteristics of Industrial Pneumatic Diaphragm Valve:

1. Elastic sealed opening and closing components to ensure no internal leakage;

2. The streamlined flow channel reduces pressure loss;

3. There is no stuffing box, so there is no leakage;

4. The valve body and cover are separated by a middle diaphragm, so that the valve cover, valve stem and other parts above the diaphragm are not corroded by the medium; 5. The diaphragm is replaceable and has low maintenance costs;

6. The diversity of lining materials can be applied to various media and has the characteristics of high strength and good corrosion resistance.