Possible faults and troubleshooting of check valve according to its structure and installation

Release time:

2024-06-08

Possible trouble of check valve and its removal

Inflexible rotation of valve disc: 1. Serious abrasion of pin shaft 2. Blockage of valve by sundries 3. Deformation of valve disc and rocker arm.

Troubleshooting: 1. Replace the pin shaft; 2. Switch and flush the valve to remove sundries; 3. Replace the disc and rocker arm

Leakage of valve seat seal: 1. The valve is not closed in place 2. There are sundries in the valve 3. The sealing surface of valve disc and valve seat is damaged

Troubleshooting: 1. Adjust the sealing position of the disc 2. Open and flush the valve to remove sundries 3. Disassemble and check the sealing surface of the disc or valve seat

Leakage of valve body and bonnet seal: accident cause: 1. Loose bonnet connecting screw 2. Damage of spiral wound gasket

Troubleshooting: 1. Tighten the screw 2. Replace the spiral wound gasket

止回阀根据其结构和安装方式

Check valve according to its structure and installation

1. 旋起式止回阀：

1. Swing check valve:

The disc of the swing check valve is in the shape of a disc, which rotates around the shaft of the valve seat channel. Because the flow forming line of the internal channel of the valve is smaller than that of the lift check valve, the flow resistance is smaller, which is suitable for the large-diameter occasions with low flow rate and unsteady flow, but it is not suitable for pulsating flow, and its sealing performance is not as good as that of the lift check valve. The swing check valve is divided into three types: single disc type, double disc type and multi disc type. These three types are mainly divided according to the valve diameter, so as to prevent the hydraulic impact when the medium stops flowing or backflows.

2.升降式止回阀：

2. Lift check valve:

A check valve with a disc sliding along the vertical centerline of the valve body. This valve can only be installed on a horizontal pipeline, and a ball can be used for the disc on a high-pressure small caliber check valve. The body shape of lift check valve is the same as that of stop valve, so its flow resistance coefficient is large. Its structure is similar to the stop valve, and the valve body and disc are the same as the stop valve. The upper part of the disc and the lower part of the bonnet are processed with guide sleeves. The disc guide cylinder can rise and fall freely in the guide cylinder of the valve disc. When the medium flows in the same direction, the disc is opened by the medium thrust. When the medium stops flowing, the disc falls on the valve seat by the self suspension, which plays a role in preventing the medium reverse flow.

The direction of medium inlet and outlet channel of straight lift check valve is perpendicular to that of valve seat channel; the direction of medium inlet and outlet channel of vertical lift check valve is the same as that of valve seat channel, and its flow resistance is smaller than that of straight lift check valve.

3. Disc check valve: a check valve whose disc rotates around the pin shaft in the valve seat. The disc check valve is simple in structure and can only be installed on the horizontal pipeline with poor sealing performance.

不可修理的阀门

Non repairable valve

1. There is no nameplate or the manufacturer shown on the nameplate is inconsistent with the valve body.

2. Severely rusted or corroded. For example: valve body perforation, sand hole, flange and screw hole corrosion is estimated to be more than 0.5mm.

3. The upper screw and the positioning screw of the middle adjusting ring are rusted with the body, which cannot be unscrewed.

4. There is a crack between the flange of the valve and the neck of the valve body.