The pump shaft of a submersible pump is so long – is it possible to do without an intermediate bearing?
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The pump shaft of a submersible pump is so long – is it possible to do without an intermediate bearing?
Without intermediate bearings, it’s impossible to use it, right?
It’s not necessary. So there are certain limitations on length, as well as restrictions on its use.
Submersible pumps with longer pump shafts generally do not use rolling bearings; instead, they rely on graphite bushings as sliding bearings for support. For even longer shafts, a support frame may be used in between. Based on our practical experience, it is preferable to use self-priming pumps whenever possible, as they are easier to maintain and their spare parts are cheaper. We have modified several existing units of this type, and all the modifications were successful
It depends on the situation. If it is a shaft (whose length is generally a little over 1 meter; I didn’t pay close attention to the exact value), it goes from the motor to the volute and then to the impeller. If a longer shaft is required in practice, such as for pools over 6 meters long, multiple shafts are needed, with couplings connecting each shaft. At regular intervals, shaft sleeves are installed between the pump shaft and the cylinder to provide positioning; furthermore, flushing water drawn from the pump outlet is used to cool the shaft sleeves and these sleeves themselves. The following image is one such example: http://image.cn.made-in-china.com/prod/000-oTQtlEyIRakB.jpg
I was fed up with the problems caused by the long-shaft submersible pumps, so I promptly replaced the two sewage pumps in the system with self-priming pumps, and the results were excellent. It turns out that submersible pumps need to be overhauled on average once a month, and the overhaul process is extremely complicated – the pump has to be lifted out of the tank entirely, several bearings and seals have to be replaced, and then it has to be put back in place, which is both time-consuming and costly. The self-priming pump has been in use for over 2 years now, and it hasn’t been serviced once; it’s still working perfectly.
Long-shaft pumps usually have segmented pump shafts. It is precisely because the long straightness cannot be guaranteed that intermediate bearings need to be installed. The lack of necessary intermediate bearings can cause other bearings to become overly fatigued, and may even lead to the breakage of the pump shaft.
In the case of a submersible pump with a long shaft, it is supported by intermediate sliding bearings
A 3-meter cantilevered submersible can be designed without intermediate guide bearings!