The malfunction of check valves may be caused by various factors, including improper selection, installation errors, medium problems, component damage, and improper maintenance. The following is a specific explanation of the situation:

Improper selection

Pressure parameter mismatch: If the nominal pressure of the check valve is less than the working pressure of the pipeline system, the valve may be damaged due to inability to withstand pressure and cannot check normally. On the contrary, if the nominal pressure is much higher than the actual working pressure, it may cause the valve to not open flexibly.

Diameter mismatch: The diameter of the check valve is not consistent with the diameter of the pipeline, which can cause abnormal flow rate of the medium. The diameter is too large and the medium flow rate is too low, which may not be enough to push the valve disc open; A small caliber can increase flow resistance and even cause valve vibration, affecting normal operation.

Type selection error: Different types of check valves are suitable for different working conditions. For example, rotary check valves are suitable for large-diameter pipelines, but in low flow, high-frequency opening and closing conditions, they may not close in a timely manner due to the heavy valve disc; Lift check valves are suitable for small-diameter pipelines. If used for large-diameter pipelines, they may be difficult to open due to the large valve disc area and high resistance.

Installation issues

Installation direction error: Failure to install the check valve according to the flow direction label can cause the valve disc to malfunction and result in reverse flow of the medium.

Improper installation position: The installation position is too close to fittings such as elbows and reducers, which can disrupt the flow state of the medium and affect the normal opening and closing of the valve disc. For example, when installed near the pump outlet, if it is too close to the pump outlet, the water hammer effect generated during pump start and stop may impact the check valve, causing damage to the valve disc.

Pipeline stress impact: During installation, if there is significant stress transmitted from the pipeline to the check valve, it will cause deformation of the valve, resulting in poor sealing between the valve disc and seat, which will affect the check performance.

Media characteristic issues

High viscosity of the medium: When the viscosity of the medium is too high, it will increase the resistance of the medium passing through the check valve, making it difficult for the valve disc to open, or even unable to fully open, affecting the flow capacity and check effect of the valve.

Impurities in the medium: Particles, impurities, etc. contained in the medium may jam the valve disc, causing it to fail to close properly, or wear down the sealing surfaces of the valve seat and disc, resulting in poor sealing and backflow of the medium.

Abnormal medium temperature: Excessive or insufficient medium temperature can affect the performance of check valve materials. For example, excessive temperature may cause the sealing material of the valve to age and deform, reducing its sealing performance; Low temperature may cause valve components to become brittle, affecting the normal operation of the valve disc.

Component damage

Valve disc damage: During long-term use, the valve disc may experience cracks, deformation, wear, and other damage due to the erosion, impact, or fatigue of the medium, resulting in the valve disc being unable to fit tightly with the valve seat and losing its check function.

Spring failure: For spring type check valves, if the spring is in a compressed or stretched state for a long time, fatigue, deformation, or fracture may occur, causing the valve disc to be unable to close normally under the action of spring force, affecting the performance of the check valve.

Sealing surface damage: The sealing surface is a key part of the check valve to achieve sealing function. Due to the erosion, wear, corrosion of the medium, and frequent friction during opening and closing, the sealing surface may be damaged by scratches, pits, deformation, etc., resulting in a decrease in sealing performance and inability to effectively prevent medium backflow.

Improper maintenance and upkeep

Lack of regular inspection: If the check valve is not inspected for a long time, problems with the valve cannot be detected in a timely manner, such as slight leakage on the sealing surface and valve disc jamming. If these problems are not dealt with in a timely manner, they will gradually deteriorate and ultimately lead to the valve not working properly.

Failure to clean in a timely manner: Failure to regularly clean impurities and dirt inside the check valve can affect the movement and sealing performance of the valve disc. At the same time, external dust, oil stains, etc. may also enter the interior of the valve, causing damage to the valve.

Failure to replace vulnerable parts on time: For some vulnerable components such as sealing gaskets, springs, etc., failure to replace them according to the prescribed cycle may result in performance degradation or failure when these components reach their service life, thereby affecting the normal operation of the check valve.