I am facing challenges with my Sulzer HZZ pump. The pump seems unable to handle the vessel's volume as the level control valve is fully open while the level keeps rising. The pump was taken to the workshop for repairs, where it was disassembled and all clearances were found to be within specifications before being reassembled. After installation, a dead head test was conducted, showing a suction gauge pressure of 8 bar and a dead head discharge pressure of 35 bar, with a data sheet SG of .6. Any insights on this issue?
Kindly share information regarding the installation process, including any details on whether it is a new or existing setup. Have you experienced any issues with the pump in the past? Are you certain that the valve is functioning properly? What is the inflow rate compared to the outflow rate on the suction side? Is the suction side operating under a vacuum or open to the atmosphere? What components are present on the suction and discharge sides? What type of fluid is being pumped, and are there any elevation changes to consider? Additionally, please provide information on the design conditions, flow discharge head, and if you have a copy of the pump curve available. Thank you.
It seems like you're dealing with a pretty complex issue here. From your description, it sounds like you've covered most bases, so I'm thinking this could be a problem with your pump not being matched correctly to the system requirements, or perhaps there might be a problem with the pump performance curves not being accurately reflected in real-world conditions. Other possible causes could include incorrect impeller sizing, a restriction in your suction pipeline, or an issue with the control valves themselves. I recommend revisiting your system requirements compared to your pump's curves and also having a chat with your Sulzer representative about this.
It seems like you've gone through a thorough process to pinpoint the problem. Based on what you've mentioned, I'd first check for issues that could be causing a decrease in the pump's capacity. These could range from a mismatch in actual fluid properties versus those assumed at design stage (viscosity, temperature), to a recirculated flow around the impeller. I'd also consider factors such as wear on internal clearances, or even air/gas entrainment in the pump. To further assess, you may want to try deviating from the design conditions and monitor pump behavior, like reducing flowrate through partially closing the discharge valve and observing the change in pump performance. This issue certainly calls for a systematic approach to identify the exact factor impacting performance.
It seems like you've really done a thorough job of testing and looking into this. It's quite baffling that your pump isn't handling the volume appropriately despite the clearances being right. However, have you looked into the efficiency of the impeller? Sometimes, the wear and tear might not be quite apparent but could affect functionality. Also, verify the continuity and validity of your control loop. Issues like changes in process conditions often cause the level control valve to stay fully open. Recheck your parameters and make sure everything matches the process and instrument diagrams. A discrepancy there could be the problem.
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Answer: - The rising level issue despite the fully open control valve could be due to the pump's inability to handle the vessel's volume efficiently.
Answer: - Possible reasons for the volume handling issues could include internal clearances not being within specifications, leading to inefficiencies in pump performance.
Answer: - The dead head test results showed a suction gauge pressure of 8 bar and a dead head discharge pressure of 35 bar, with a data sheet SG of .6. This information can provide insights into the pump's performance under specific conditions.
Answer: - Troubleshooting steps could involve checking for any discrepancies in the pump's internal clearances, ensuring proper assembly after repairs, and analyzing test results to identify potential causes of the volume handling problems.
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