Viti Industry analyzes for you: Why do high-pressure differential steam traps often break down

Viti Industry believes that the frequent damage of high-pressure differential steam traps is usually caused by the following reasons, which need to be comprehensively analyzed in combination with the working conditions and the type of valve:

I. Mechanical damage caused by high pressure difference

Flash evaporation and cavitation: Under high pressure difference, when high-temperature condensate water passes through the valve port, the pressure drops sharply, and part of the liquid vaporizes instantly (flash evaporation), forming high-speed bubbles that impact the surface of the valve core and valve seat, causing material spalling (cavitation). Long-term action will damage the sealing surface, causing internal leakage or perforation of the valve body.

2. High-frequency water hammer impact: The high pressure difference causes the condensate water discharge speed to be extremely high. When the valve core is frequently opened and closed, it may trigger the water hammer effect, generating instantaneous pressure waves that impact the internal components of the valve, leading to mechanical fatigue or fracture.

Second, improper selection or design

Valve type mismatch: For instance, in high-pressure difference conditions (such as > 100bar), if ordinary thermal dynamic or bimetallic steam traps are selected, their structures are difficult to withstand high impacts. Therefore, multi-stage pressure reducing labyrinth type or special anti-cavitation design valves should be chosen.

2. Too large or too small diameter: A too small diameter leads to an excessively high flow rate, accelerating wear. If the diameter is too large, it will cause low-frequency operation, and the valve core is prone to jamming or carbon buildup on the sealing area.

3. Poor material durability: The valve core and valve seat have not undergone hardening treatment (such as tungsten carbide, Stellite alloy) or the valve body material (such as ordinary cast iron) is not suitable for high-pressure difference environments.

Iii. Abnormal working conditions or system issues

1. Overpressure or pressure fluctuation: Sudden increase in upstream pressure or too low back pressure (such as unstable pressure in the recovery system) causes the actual pressure difference to far exceed the design value.

2. Impurities carried by high-temperature saturated water: When the boiler water is not treated, hard particles (such as iron oxide and scale) are washed away by the high-speed water flow on the valve internal components, accelerating wear.

3. Frequent cold starts: When the system starts and stops frequently, the condensate load changes sharply, and the steam trap is subjected to alternating stress, shortening its service life.

Iv. Installation and Maintenance Issues

1. Incorrect installation: The inlet pipe is too long (> 3m without support), the outlet pipe is against the slope or no air exhaust device is installed, resulting in water hammer or air lock.

2. Lack of maintenance: The filter screen was not cleaned regularly and the sealing performance was not checked. Minor problems accumulated into serious damage.

Suggestions for solutions to frequent damage of high-pressure differential steam traps

1. Re-selection: Prioritize the use of high-pressure differential dedicated steam traps (such as those provided by Vitesse in Germany), and adopt multi-stage pressure reduction or labyrinth structure.

2. Optimize the system

Install a pressure reducing valve or flash tank before the steam trap to reduce the pressure in sections.

Add a steam-water separator to reduce the impact of impurities.

3. Strengthen maintenance

Check the valve body for leakage or abnormal noise every month.

Disassemble and inspect once a year, replace the worn valve core. It is recommended to choose industrial valves provided by Viti Industry. Maintenance does not require cutting the valve from the pipeline and can be replaced and maintained online.

4. Installation correction

Ensure that the outlet pipe diameter is greater than or equal to the inlet, and discharge vertically downward.

Under high pressure difference conditions, it is recommended to install a muffler or diffuser at the outlet to reduce the flow rate.

By conducting targeted analysis of the working conditions and valve types, the failure rate of high-pressure differential steam traps can be significantly reduced. The main steam trap of a certain power plant (with a pressure difference of 12MPa) originally used a thermodynamic valve, with an average service life of 3 months. After research and technical verification by Viti Industry, the multi-stage labyrinth steam trap provided by Viti Industry was adopted, and a pre-pressure reducing valve was added, extending the service life to more than two years.