What Causes The Check Valve Disc To Break?

Check valves play a critical role in many industrial fluid control systems, ensuring proper operation and safety by allowing fluid to flow in one direction. However, the failure of the check valve disc break occurs from time to time, which not only leads to direct problems such as fluid leakage and system pressure instability, but also can cause the entire process to be interrupted, causing economic losses and safety hazards to the enterprise. Exploring the causes of disc fracture of check valves is of critical significance to improve the reliability of check valves, optimize the design and maintenance of fluid control systems, and ensure the continuity and stability of industrial production. 

The check valve disc can break due to several reasons:
1. High - velocity Fluid Flow
Impact and Fatigue: When the fluid velocity through the check valve is extremely high, the disc can be subjected to intense impact forces. The rapid change in the direction of fluid flow as it hits the disc can cause mechanical stress. Over time, this repeated impact and stress can lead to fatigue cracks in the disc material. For example, in a high - pressure water pipeline system where there are sudden changes in flow rate, the check valve disc may experience significant force each time the water flow direction changes, increasing the risk of breakage.
Cavitation: High - velocity fluid flow can also lead to cavitation. As the fluid pressure drops below the vapor pressure, vapor bubbles form. When these bubbles collapse near the valve disc, they create shock waves that can cause pitting and erosion on the disc surface. Severe cavitation can weaken the disc structure to the point where it breaks. This is often seen in pumps' discharge lines where the pressure fluctuations are more likely to trigger cavitation.

2. Foreign Object Damage
Debris in the Fluid: The presence of solid debris such as sand, metal fragments, or other particulate matter in the fluid can directly impact the disc. These foreign objects can scratch, dent, or even chip the disc surface. If a large enough piece of debris gets lodged between the disc and the valve seat or strikes the disc with enough force, it can cause the disc to break. For example, in an oil pipeline, rust particles or scale from the pipe walls can enter the valve and damage the disc.

Installation - related Debris: During installation, if there is dirt, metal shavings, or other construction - related debris left inside the valve, it can also lead to damage. As the valve is put into operation, this debris can interact with the disc and cause it to malfunction or break.

3. Material Defects
Manufacturing Flaws: Imperfections in the manufacturing process of the valve disc can lead to weaknesses. These may include porosity in the casting of the disc, improper heat treatment that affects the material's strength, or machining errors that introduce stress - concentrating features such as sharp corners or grooves. A disc with such manufacturing defects is more likely to break under normal operating conditions. For example, a disc with microscopic cracks due to improper casting may expand and lead to complete failure during operation.

Sub - standard Materials: If the valve disc is made from materials that do not meet the required specifications, its strength and durability will be compromised. Low - quality alloys or plastics may not be able to withstand the operating conditions such as pressure, temperature, and chemical exposure. For instance, using a plastic disc that is not resistant to the chemicals in the fluid can cause the disc to degrade and break.

4. Incorrect Installation and Operation
Misalignment: If the check valve is not installed correctly and the disc is misaligned with respect to the valve seat or the flow path, it can cause uneven wear and stress distribution. The disc may not close properly, leading to leakage and additional stress due to the continuous back - and - forth movement caused by the unbalanced forces. This misalignment - induced stress can eventually cause the disc to break. In a piping system where the valve is installed at an angle that is not in line with the intended flow direction, such problems are more likely to occur.

Over - pressurization: Operating the check valve beyond its rated pressure capacity can put excessive stress on the disc. The disc may not be designed to handle the high pressure, and as a result, it can deform and break. This can happen if there is a sudden pressure surge in the system due to pump start - up, valve closure in a high - pressure line, or other operational factors.

5. Corrosion and Chemical Attack
Chemical Compatibility: If the valve disc material is not chemically compatible with the fluid passing through the valve, it can lead to corrosion. Chemical reactions between the fluid and the disc material can gradually eat away at the surface, reducing its thickness and strength. For example, in a chemical processing plant, if a check valve with a metal disc is used to handle a corrosive acid solution, the acid can corrode the disc, making it more prone to breakage.

Electrochemical Corrosion: In systems where there is a combination of different metals and an electrolyte (such as a conductive fluid), electrochemical corrosion can occur. This can cause pitting and weakening of the disc material. The galvanic cell formed between different metals can accelerate the corrosion process and lead to premature failure of the valve disc.