What standards should be followed for the factory acceptance of centrifugal pumps?
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In a few days, I’m going to the manufacturer’s site to witness the tests, including those related to performance, NPSH, and mechanical operation. So I would like to ask the seniors at Haichuan: what experience do you have when going to the manufacturing plant to witness tests or when inspecting equipment after it leaves the factory? Or what are some standards that can be used? Are there any hidden issues or traps on the part of the manufacturer?
Dear, there are international standards for this; you should do some research on it yourself
For testing, there are requirements specified in the pump standards. Different standards have different requirements. Which standard to use depends on the standard of pump you purchase. I haven’t been there to witness the tests; I’ve only seen the test reports. Discussions regarding technical specifications also involved talks about these tests. In my opinion, the points that need attention include: performance tests. Some manufacturers claim to have taken many measurements, but they actually fail to measure the several points required by the standards (for API610, at least 5 points are required: the fully closed position, the point with the minimum continuous stable flow rate, the intermediate point between the minimum and rated flow rates, the rated flow rate point, and the maximum allowable flow rate point). The overall performance profile of the pump still isn’t clear in such cases. Mechanical operation test: This is carried out together with the performance test; according to the standards, it should be conducted for 4 hours, although some standards require more than 1 hour, and this can be discussed. However, it is necessary to run the pump for a period of time after all its conditions have stabilized, and to measure data during that stable phase. NPSHr test: This test is not always required; it is only conducted for the pump’s NPSHa-NPSHr values
The standards and inspection items for factory acceptance depend primarily on what is specified in the contract between you and the manufacturer. For example, in API 610, for a four-hour test as well, there are actually several mutually exclusive definitions. As for the points that need attention: 1. The manufacturer should submit the testing procedures and evaluation criteria in advance, and you should check each item against the contract to see if there are any omissions or errors. Especially the criteria for making decisions must be established in advance; otherwise, when it’s time to conduct the test and there’s pressure to ship the goods right away, you’ll end up in a difficult situation as to whether to sign or not. This is a common trick used by manufacturers ； 2. Regarding the judgment criteria, system measurement errors need to be considered in advance. If the manufacturer does not specify, it needs to be agreed upon in advance; under no circumstances should a negative deviation be considered ； 3. It is recommended to check the calibration date and calibration certificate of the measuring instruments ； 4. Pay attention to the nameplate; the correct sequence is to install the nameplate first, and then proceed with testing. I have encountered a situation where testing is done first, and then labeling is carried out. It was not until I arrived at the site that I realized things were in disarray, because I had over a dozen pump sets, with only the impeller diameters varying. Then, check them one by one on site.
The color of the paint must be in line with the technical specifications. Check whether there are any sand holes in the pump casing; the net positive suction head must meet the design requirements, and the flow rate must also comply with the design specifications
They generally won’t cheat you. It’s about credibility. The original poster just needs to meet the standard requirements. It is also necessary for the technical personnel from the other party to be on site, and your contract department staff should also be involved. Also, the manufacturer will give the original poster a surprise – just don’t get too excited when that happens,,,
For such witness tests, the manufacturer should provide a test outline that includes the relevant standard requirements to be met. Generally, the standard parameters are listed; by comparing them with the actual parameters, it is easy to determine whether it is qualified. The key is for the witnesses to be familiar with the relevant documents and materials in advance, and to understand the main performance requirements.
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