Causes of cracking of fluoroplastic pump impeller and back cover
Thread Content
The fluoroplastic circulation pump used in our company's chlorinated paraffin production is the FSB type. The new pump has been used for about a year. During the maintenance and disassembly in the past few days, it was discovered that the fluoroplastics of the impeller and back cover were cracked, involving multiple pumps. The maximum temperature of the operating conditions is about 110°C. The media in contact are liquid wax, chlorinated paraffin, chlorine, and hydrogen chloride. Please help us analyze the cause of the damage: handshake
There are two reasons: 1. Manufacturer’s problem: inappropriate material selection ； Poor pour quality. 2. Self-problem: The operating temperature of the medium exceeds the design value ； The operating medium does not match the design medium ； Cavitation and air binding may damage the pump during operation.
……Thanks to the two friends above for their replies. Are the impurities mentioned on the second floor in the pump materials or in the production materials? ? , the production materials are liquid and have no solid impurities. According to the pump instructions, there should be no problem with the temperature resistance and corrosion resistance of fluoroplastics. Does the gas cavitation have something to do with the small amount of chlorine and hydrogen chloride in the circulating materials...:)
This material is ultra-high molecular weight polyethylene, and its operating temperature is suitable for temperatures below 80 degrees Celsius. Using 110℃ plastic material requires PVDF (polyvinylidene fluoride) or F46 (polyperfluoroethylene propylene). www.yxcrbf.com
Our pump is made of F46 material: handshake
It is estimated that the boss spent the price of F46 or PVDF to buy a pump made of ultra-high molecular weight polyethylene. In a word, the material is not good.
There are too many polyethylene products on the market pretending to be F46. Even if it is made of fluoroplastic alloy, it is recommended to use high temperature resistant PFA material if the temperature is 110 degrees. It looks a bit like polyethylene in appearance. It is recommended to throw it on the cement floor from a height. If the sound is crisp and clear, it is a real polyethylene hammer.
Typical Jiangsu JJ pumps, don’t say any pump is a fluoroplastic pump: @ ultra-high molecular weight polyethylene, vinylidene fluoride and hexafluoropropylene copolymer, etc.
Caused by repeated expansion and contraction caused by temperature changes