Two stage pump and L3/D4
Two stage pump and L3/D4
(OP)
I have a Hayward Tyler 2 stage end suction overhung centrifugal pump suffering from mechanical seal and thrust bearing problems. The outboard end of the shaft is supported in a steady bush inside the pump case (similar to a wear ring)operating speed is 2950rpm. Can the stiffness of the shaft of this style of pump be reviewed by the use of L3/D4, or would it be considered a "between bearings" pump. If it is suitable for review by L3/D4, where would the "L" be calculated from? from centre of NDE bearing to mid-point between impellers, or to mid-point of outboard impeller? If it is considered a "between bearings" pump is there a comparable calculation for shaft stifness?





RE: Two stage pump and L3/D4
The only true solution for a pump of this type is to replace it with a proper between bearings pump.
RE: Two stage pump and L3/D4
It probably needs modification to the existing design and is also dependent on the product being pumped.
I have seen this used in small and very large axial / mixed flow vertical line-shaft driven pumps to support the shaft on the inlet end of the impeller/s (turbine).
Although I would agree with JJPellin - change the unit to a better design.
Naresuan University
Phitsanulok
Thailand
RE: Two stage pump and L3/D4
Naresuan University
Phitsanulok
Thailand
RE: Two stage pump and L3/D4