Stuffing Box Pressure - Quick Calc

[Milkboy]

Hello

To get the box pressure I have used a quick calc

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Suction + 1/3 Differential = Box

(Dis - Suction) = Diff

NB - With Balance Holes
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I have a pump where there is NO BALANCE HOLES in the impeller and would like to est. box pressure

Is there a similar quick calc to get this ??


TIA





-
Milkboy

 

[panapat]

Milkboy,

The equation in the other email is good. But if your impeller has pumpout vanes on the backside or the pump has an expeller behind the impeller, the stuffing box pressure will be greatly reduced. This will vary by manufacturer.

Panapat

 

[longeron]

The orientation and kind of pump makes a difference as well. You'll find that the box pressure for most vertical-in-line pumps is about equal to discharge pressure. A chamber in a multistage pump will usually be at a pressure close to that of the suction of the middle stage, but that depends upon whether or not the pump uses a balance line. You'll find a good amount of information about this in older pump catalouges. The newer print versions tend to skip this. Some will even have the conditions in the seal chamber in terms of discharge head.