Seeking analysis of the reasons for the rupture of the bellows in a submersible pump
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At present, our company’s bottom suction pump is experiencing a problem: the pressure at the pump outlet has decreased, from 2.2 MPa to 1.5 MPa, and the vibration level is around 10 mm/s. It is suspected that the outlet valve was closed due to vacuum conditions; however, the pressure did not change even after closing the valve several times. After shutting down the pump for inspection, no issues were found, so the pump was tried again. Sealing problems were severe on the low-pressure side; upon disassembling the pump, water was found inside it, and the bellows on the low-pressure side was broken with severe buildup of scale inside it. The seal oil pressure is normal; could the experts please analyze the reason? :handshake Does the water enter through the bellows?
The bellows are broken; there were issues with the welding during processing by the sealing manufacturer
Scaling on the bellows causes the bellows to return to their position improperly; uneven stress leads to fracture, and air is drawn back into the pump, resulting in vacuum conditions.
The pressure inside the pump chamber should be higher than that of the softened water. When the bellows breaks, it’s likely that the sealing oil leaks out first; it shouldn’t be sucked in