The flanged diaphragm valve is a special type of truncated valve that appeared in the 1920s. Its opening is a membrane made of soft material.
Separate the body cavity from the bonnet and the drive part, hence the diaphragm valve.
The characteristics of flanged diaphragm valve are as follows:
The most prominent feature is the lower part of the diaphragm valve body cavity and the upper cover inner chamber is separated, the located above the diaphragm of the stem and disc parts from corrosion medium, such as eliminating the packing seal structure, and won’t produce leakage of medium.
1. Use rubber or plastic to seal the diaphragm, sealing better. Since the diaphragm is a vulnerable part, it should be replaced regularly with the characteristics of the medium.
2. Limited by diaphragm material, diaphragm valves are suitable for low-pressure and relatively low-temperature occasions.
3. The diaphragm valve can be divided into three types: house type, direct current, cut-off, straight-through type, gate type and right Angle; The form of connection is usually flange. The driving mode can be divided into three kinds: manual, electric and pneumatic. The aerodynamic drive is divided into three types: regular, closed and reciprocating.
4. It should not be used in pipelines with high temperature above 60 degrees and conveying organic solvents and strong oxidizing medium
Diaphragm valves are used to open or block airflow in a fluid system of 1.3 x 10-5 ~ 2.5 X106Pa.
Main performance of flanged diaphragm valve
Leakage rate: no more than 1.3 times 10-5pa. L/S;
Materials: 304, 316L;
Working medium: gas, water, oil;
Working temperature: fluorine rubber – 30 ℃ ~ + 150 ℃;
Principle of flanged diaphragm valve: to drive the drive screw with compressed air, make the valve core move up and down, and move the diaphragm up and down to close and open it.
Features: compact, simple, small size, beautiful appearance;
The switch is guided and stable. The closing moment is small and the life span is greater than 300,000 times. The diaphragm pressure can be adjusted automatically, with uniform pressure and reliable sealing. The diaphragm loading valve core adopts push-in type and convenient replacement.
1. The valve is composed of valve body, bonnet, stem, disc, diaphragm and other driving parts.
2. The opening and closing of the valve is driven by the connecting shaft of the electric device to drive the stem nut, so that the valve stem can be used to drive the disc lift and lift when the shaft is moving.
3. When the power supply failure and interrupts, and are in urgent need of the emergency conditions of opening and closing of the valve, first of all, should be “hand – electric switch handle” convert to engraved with manual marking position, then can flash by rotating the handwheel door opening and closing. When rotating clockwise, the valve can be closed. Instead, it opens.
4. When the electric operation is to be restored, the switch handle must be transferred to the position of the electric marking, before the electric operation can be carried out.
maintenance and installation use precautions
1. The valve should be stored in a dry and ventilated room, which is strictly prohibited.
2. The access end of the inventory valve must be sealed to prevent the foreign body from entering the inner cavity and damage the sealing part. And avoid contact with oil or other flammable materials.
3. The metal surface of this valve should be removed from dirt and coated with anti-rust agent.
4. Do not brush grease material on the surface of rubber layer or rubber diaphragm to avoid rubber swelling and affect valve service life.
5. Rotate the handwheel counterclockwise during the period of storage or during the outage to keep the valve in a microstate and avoid the loss of elasticity due to prolonged compression.
6. During transportation or installation, the sling shall not be attached to the handwheel or stem. It is forbidden to strike against other metals or hard objects in case of damage to parts and lining. String 6
7. Prior to installation, the operating conditions and media of the pipeline shall be carefully checked to conform to the applicable scope of the provisions of this valve, so as to avoid unnecessary losses caused by improper selection, which is caused by accidents.
8. This valve shall not be used for vacuum tube road, but it shall be installed in two directions at any position in the pipeline, but it shall be convenient for operation and maintenance.
9. When installing, clean the valve body cavity, prevent fouling or damage sealing parts, and check whether the connecting bolts of each part are even fastening.
10. The parts that are in contact with the medium must be constantly checked in operation, and the damaged parts are replaced regularly according to the actual usage.
11. When changing the diaphragm, be careful not to tighten the diaphragm too tightly or too loose.
12. The valve shall be cleaned and exposed to the medium to extend the service life during the period of discontinued use.
13. When operating the vertical valve manually, it is not allowed to open the valve with auxiliary lever to avoid excessive torque and damage to the driving part or sealing part.
14. After repair, the valve shall be sealed in accordance with the relevant test requirements before application. And make a maintenance note not to prepare for the examination.
Source: China Flanged Diaphragm Valve Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)