【JST-048】One-on-one consultation service for centrifugal pump technology experts

This post was last edited by yuchenchf on 2012-4-4 08:41. Hello: I have a question regarding magnetic pumps. There is a Dandong Klon magnetic pump in use at the site for handling 37% nitric acid, and the isolation sleeve of this pump has leaked, allowing acid to enter the bearing box. Question 1: The original isolation gasket used was a graphite gasket; it was damaged during maintenance and replaced with a PTFE gasket, which causes some leakage when in use. May I ask if this gasket will work? (The temperature is not high.) Regarding how to address leaks: Question 2: After the bearing housing is corroded by acid, using kerosene for cleaning results in the lubricant deteriorating rapidly, along with the presence of many impurities similar to oxide scale. Are there any good cleaning methods available after acidic corrosion? (Moderator’s note: Refer to answer on floor 3 for guidance.)

I’m sorry, I’ve been quite busy these days and didn’t see it. I’m not very familiar with magnetic pump technology, so I can only provide a brief answer to your question. Magnetic pumps are leak-free pumps, and the gaskets used must ensure that the medium does not leak outward. Therefore, leakage after replacing them with PTFE gaskets is not allowed; in particular, leakage into the bearing housing is absolutely unacceptable. For areas that have been corroded by acid, clean them with alkaline water, then rinse with clean water and dry them. After that, use kerosene to check for any leaks, and be sure to also check whether the mounting holes have been corroded.

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This post was last edited by yuchenchf on 2012-4-4 08:42. I have a question: For Sulzer cartridge pumps, after the mouth ring is tightened, the radius of the mouth ring is increased by 30 tooth pitches. After installation and during testing, abnormal vibration occurs when the outlet valve is closed; once the valve is opened, the vibration increases rapidly, reaching quite high levels. There are suspicions of a balance issue, but the pump was not installed for half a year after it arrived, and no problems were detected during testing. Solve? (Publisher’s note: Please refer to floor 7 when replying.)

This post was last edited by bage on 2012-3-14 09:49. Pump vibration is a rather complex issue; it’s difficult to determine what the problem is based solely on your description, and it’s even less possible to simply conclude that imbalance is the cause. From your description, it seems that the pump was working normally at first, but then the mouth ring seized. During maintenance, the mouth ring was enlarged by 30 threads before being reinstalled; however, vibration levels became excessive when the pump started running again. Is that correct? So before reinstalling, did you conduct a thorough inspection of the important components such as shafts, guide bearings, shaft sleeves, and rigid couplings to check whether their dimensions and runout are still within acceptable limits? Especially, is the shaft bent? If there were no problems during normal operation but vibration increased after maintenance, then it is unlikely to be a balance issue; it could be that some parts are deformed or not installed correctly. Check each component again according to the operation and maintenance manual, and measure various clearances, tolerances, etc., to see if anything is incorrect.

It seems we have to bring the manufacturer over; that’s troublesome

May I ask: for the liquid ring hydrogen compressor of model JSKA303, manufactured in Zibo, Shandong, what is the single-end face clearance?

I only know about centrifugal pumps. I don’t understand the compressor.

Haiyou: Seeking technical assistance regarding Jidi. The performance parameters of our company’s coking water pump are as follows: Q: 180 m3/h, H: 1920 m; rated power is 1600 KW, while the actual power is 1400 KW. The inlet tank pressure is at atmospheric pressure, while the outlet pressure is around 20 Mpa. The design pressure of our company’s coking system is 25 Mpa. I would like to increase the pressure in the defocusing system. Do any experts have any good suggestions or ideas?