API Seal flush plan 32
API Seal flush plan 32
(OP)
Hi Frnds
In case of pumps with API seal flush plan 32, what should be the seal flush pressure.
how much more than suction pressure?
In case of pumps with API seal flush plan 32, what should be the seal flush pressure.
how much more than suction pressure?





RE: API Seal flush plan 32
We normally adjust API Plan 32 flush for a target flow rate which is defined by the seal manufacturer for the particular service. A rule-of-thumb for 3600 rpm pumps would be to inject 1 gpm for each inch of seal diameter. But, since Plan 32 is arguably the most expensive flush plan, there is a value in limiting the flush flow to the lowest value required for good seal reliability.
If you are forced to adjust the flush flow based only on pressure, you need to adjust it relative to seal chamber pressure, not suction pressure. You need to take into account the configuration of the seal chamber, including the design of the throat bushing.
If I was forced to adjust the seal flush with no other information, I would perform the following: Block in the seal flush and read the seal chamber pressure with no net flow in or out. Open up the seal flush until the seal chamber pressure increased by at least 10 psi. Many people would use a higher value. Some sources suggest 25 psi above seal chamber pressure. This would probably result in excessive flush flow. But, at least you would know that you were getting a good flow.
Johnny Pellin
RE: API Seal flush plan 32
RE: API Seal flush plan 32
We are using seal flush 32 in combination with plan 52.
Pump service is HD Polyethylene slurry. Hexane is used as a flushing media in plan 32 and White oil in plan 52.
A throat bushing is installed in the seal.
Now my doubt is:: With the same throat bushing, can we vary (increase) the flow rates from seal to the pump casing. Actually our process guys needs more hexane from seal flush plan 32 going to the impeller. This is to minimize sticky polymer depositions on the impeller.
If yes, does increased flow rate affects the seal life / performance.
RE: API Seal flush plan 32
You are only giving us tiny bites of information to evaluate. If the process requires injection of additional flush beyond the requirements of the seal, I would suggest having the process engineers find a different place to inject it. Using the seal as an injection point does not seem wise given the limited information provided.
We once had a bright, young process engineer use the high point on the balance line of a large multi-stage pumps to inject a chemical for activation of the unit catalyst. The pump failed in thrust which required a very expensive, unplanned overhaul. I would suggest you be very careful about using seal flush for a process need.
Johnny Pellin
RE: API Seal flush plan 32