CPVC Butterfly Valve is made by CPVC body with seat EPDM or FPM, wafer type or lug type as per standard DIN, ANSI, JIS, CNS, operated by hand lever, gear operate, Electric Actuator and pneumatic actuator. Size from 2" to 24", working pressure by PN10, temperature from 0 degree to 95 degree. CPVC BUTTERFLY VALVE is usually used in chemical industrial for acidic and alkaline medium delivery
Ningbo RMI Plastic Co.,Ltd offer CPVC butterfly valve with specification:
Size range:DN50~DN600 (2 inch ~ 24 inch) CPVC Butterfly Valve,Acid Butterfly Valve,Chloride Butterfly Valve,Butterfly Valve CPVC Ningbo RMI Plastic Co.,Ltd , https://www.rmiplast.com
Body materials:CPVC
Seat material:VITON,EPDM
Lug connection: Flange ANSI CL150, JIS10K, DIN PN10
Design pressure:0.2~1.0Mpa (PN2~10 bar)
Influencing factors and discussion on the life reduction of one-way valve spring
Since the stiffness of the active spring is greater than that of the original spring, under installation conditions (spring pre-compression), the actual maximum and minimum working loads of the spring significantly deviate from the standard load range. This deviation becomes a key factor contributing to the shortened service life of the spring. Additionally, the high speed of the ammonia pump further accelerates this issue.
When the pump speed exceeds 180 rpm, the average service life of the current spring drops to just two weeks. The main reason behind this is that as the speed increases, the movement of the plunger and Check Valve spool becomes faster. This leads to an increase in the inertia force acting on the one-way spool, which in turn increases the working stroke of the spring. As a result, the maximum working load on the spring rises, pushing it even further out of the standard working range and reducing its lifespan.
To address this problem, a specific adjustment was made: the outlet check valve spring support was turned downward by 5 units, effectively reducing the pre-compression amount to 10. Under normal draining conditions, the maximum displacement of the spring is 5, so the overall compression is reduced. This adjustment helps bring the actual maximum and minimum working loads back within the standard operating range of the spring.
Because the calculation results for both the inlet and outlet springs are similar, the same adjustment method was applied to the inlet spring. By turning the inlet spring's support downward by 5 units, the pre-compression amount could be properly adjusted, improving the efficiency of the high-pressure ammonia pump and reducing the pump's running speed. This, in turn, helps extend the service life of the spring.
Key measures also include preventing leaks from the one-way valve static seal, the pump outlet Safety Valve , the outlet sub-line valve, and damage to the check valve sealing surface. Any signs of leakage must be addressed immediately—especially issues related to the one-way valve static seal. Failure to do so can lead to a vicious cycle where increased pump speed further reduces spring and check valve life, potentially causing serious damage to the cylinder sealing surface.
The root cause of the short spring life was the unreasonable distribution of the existing spring’s working load, combined with the high-speed operation of the ammonia pump. On February 1, 2003, the pre-compression amount of the inlet and outlet check valve springs was adjusted, which helped bring the spring loads back into the standard range. At the same time, improved maintenance and repair efforts were implemented to enhance the pump’s operational efficiency and reduce its running speed.