Individual testing of magnetic pump and shielded pump units
Thread Content
Everyone, I would like to ask whether magnetic pump and shielded pump systems require individual trial runs. As far as I know, the structure of these two types of pumps is rather special, and it is not necessary to conduct individual unit tests before they are put into operation. Is this view correct? Also, before conducting a single-unit test run of the mechanical pump (centrifugal pump), it is necessary to replace the pump’s inlet filter with a temporary one. I would like to ask: is the mesh size of the temporary filter finer than that of the regular filter?
Such pumps are generally not tested individually; due to their special structure which does not allow them to operate without liquid, they are usually tested with water along with the system or put into operation with material fed directly, and the forward and reverse rotation is determined using jog operation. For details, please refer to the pump’s factory documents/manuals for use and maintenance! For information on how to determine the forward and reverse rotation of shielded pumps, please refer to: http://bbs.hcbbs.com/viewthread.php?tid=239235&extra=page%3D2%26amp%3Bfilter%3Dtype%26amp%3Btypeid%3D2. This post was last edited by clguan on 2008-11-9 at 19:39.]
Magnetic pump – runs idle or operates without liquid. It is recommended to install an anti-idle protection device for the pump, which will shut it down automatically within 2 seconds when idling, thus protecting the pump from damage. Electronic sample available at: http://www.dnpump.com/PicUp/200910162202501.pdf If you want less maintenance, opt for a built-in anti-idle protection device – it saves time!
The statement above is not accurate; for pump units, it is generally required to conduct individual tests before putting them into operation. Even for those pump units that require full-scale testing with actual materials, trial operations must be carried out before the system starts operating properly. Essentially, both magnetic drive pumps and canned motor pumps belong to the category of centrifugal pumps; therefore, their basic operation is similar to that of ordinary centrifugal pumps. The only difference is that they eliminate the mechanical seal mechanism to achieve leak-free operation compared to regular centrifugal pumps. Under normal circumstances, the instrument interlock protection system should be activated during commissioning (whereas for ordinary centrifugal pumps, only manual monitoring is used), such as for parameters like pressure difference and temperature. Moreover, strict requirements are placed on the evacuation of the pump chamber; it is essential to ensure thorough exhaust before commissioning. The other requirements are the same as those for ordinary centrifugal pumps.
It also depends on the specific circumstances whether to use a temporary filter before commissioning. If there is suspicion that there are many impurities in the pipes or if the material of the filter element is special and could cause damage to the regular filter, then a temporary filter is recommended. The mesh size of the temporary filter should be the same as that of the regular filter; generally, 30–40 mesh is sufficient. If the mesh size is too fine, vacuum may occur, while if it’s too coarse, impurities may enter the pump chamber.
The temporary filter mentioned upstairs seems to be too fine; such filters are used to capture impurities that have not been removed properly from the pipes or equipment, such as welding slag, so 80-100 mesh is sufficient.
Just carry out a water test directly; first, rotate the pump to examine the friction within its chamber. Observe the pump’s rotation direction to prevent reverse rotation. The condition of the pump can be checked using a pressure gauge; it is sufficient to reach the designed operating pressure. This experiment should be carried out with the assistance of the manufacturer. And combined with on-site pump operation training.