The pump cannot be rotated during the heating-up process of a heat pump; then when is it appropriate to rotate the pump?
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We have a pump whose working medium operates at 130°C. It is necessary to warm up the pump before starting it. I’ve checked many sources, and all of them state that the pump should not be rotated during the warming process. So when is the right time to rotate the pump? It definitely needs to be rotated before starting it properly. Does anyone with relevant experience or information have any suggestions? Thank you. If you have any, you can send it to 492355735@qq. com, thank you so much:(
Is it really true that the equipment management regulations in our factory don’t include a requirement to turn the pump shaft before starting it? It is stated only that the standby pump should be turned 180 degrees per day; after the pump is shut down, it should be turned 3 to 5 times. When a hot oil pump is shut down for cooling, it should be turned every 10 minutes until the cooling process is complete.
The turbine should be turned during the preheating process.
Pre-starting shaft rotation refers to the act of rotating the shaft after all process conditions and equipment requirements have been met. For high-temperature equipment, it is mainly to eliminate thermal expansion and contraction, thereby preventing certain vulnerable components such as mechanical seals from not being heated evenly
When heating the pump, it should be rotated to prevent thermal bending
The hot oil pump should be turned manually while it is being warmed up to prevent the shaft from bending
Our traditional mindset is that a heat pump must have a crank mechanism to ensure adequate preheating. I used to think the same way too. Some time ago, when discussing pump specifications, many well-known pump manufacturers such as Fox, Ebara, and Sulzer said that it is not necessary to rotate the pump shaft; rotating it once before starting is sufficient. The reason for this is that thanks to improved manufacturing techniques, the precision of the rotor components is very high. In the case of hot oil pumps, uneven expansion of the sealing rings during preheating, along with the possible presence of solids in the fluid, can lead to the sealing rings being damaged as a result of low rotation speeds. Therefore, it is not recommended to rotate the shaft during preheating; instead, this should be done after the temperature has risen enough so that all expansions have taken place and the proper gaps are maintained. Such a design typically measures the temperature difference between the upper and lower parts of the pump casing to determine whether sufficient preheating has taken place.
According to the reference books I’ve consulted, it is not allowed to turn the turbine during the temperature rise process; yet some sites still do so. I’m confused – when is it appropriate to turn the turbine?