Running pump in reverse flow
Running pump in reverse flow
(OP)
Hi There,
Have anybody experienced reverse flow in a running pump? I have been told by plant operator that once he finished unloading first compartment and remove the empty suction hose to next compartmnet there was product flowing back through pump suction and cause spill. Pump was unloading product from truck to above ground tank with 15meter height when this happened. Pumpe can make 16 meter head. Please somebody tell me how this back flow is possible while the pump is running??
Have anybody experienced reverse flow in a running pump? I have been told by plant operator that once he finished unloading first compartment and remove the empty suction hose to next compartmnet there was product flowing back through pump suction and cause spill. Pump was unloading product from truck to above ground tank with 15meter height when this happened. Pumpe can make 16 meter head. Please somebody tell me how this back flow is possible while the pump is running??





RE: Running pump in reverse flow
Nothing new under the sun. Centrifugal pumps may experience reverse flow in event of sudden power cut to the pump driver and where the check valve fails (or it's not present at all) .
The pump speed reduces quite rapidly (low inertial force of rotating parts) until the pump is not capable to overcome the system head. It's at that point the flow direction reverses and passing from discharge to suction side.
RE: Running pump in reverse flow
Ted
RE: Running pump in reverse flow
Or the pump was not actually running. The size of the spill may be an indication. The lost volume of a suction line spill may be equal to the volume of a few feet of suction line. If the pump was actually off the spill volume will be greater and will be related to the volume of the discharge line up to the highest point.
Was this a centrifugal pump or a positive displacement pump?
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Running pump in reverse flow
RE: Running pump in reverse flow
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Running pump in reverse flow
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)
RE: Running pump in reverse flow
Check the NPSH and the elevation of the feeding pipe. If the NPSH is 2 ft head, then the pipe needs to be full a minimum of 2 ft to prevent back flow.
RE: Running pump in reverse flow
Let your acquaintances be many, but your advisors one in a thousand' ... Book of Ecclesiasticus