Centrifugal pump - suction reducer - drain required
Centrifugal pump - suction reducer - drain required
(OP)
Hi
I'm wondering, if you have a drain on the pump itself, is it necesary to have a low pint drain on the suction side then?
The pipeline is horizontal and with the same elevation on both suction side and discharge side, so a drain in the pump will empty all the liquid in the pipeline.
http://tinypic.com/r/11azp6x/5
I'm wondering, if you have a drain on the pump itself, is it necesary to have a low pint drain on the suction side then?
The pipeline is horizontal and with the same elevation on both suction side and discharge side, so a drain in the pump will empty all the liquid in the pipeline.
http://tinypic.com/r/11azp6x/5





RE: Centrifugal pump - suction reducer - drain required
HPost
RE: Centrifugal pump - suction reducer - drain required
The pump manufacturer would normally put the smallest drain possible for the area available at the bottom of the pump and to meet their requirement for hydro testing the pump assembly in the factory.
If your system is a very large volume and you may want to drain it fast then you should consider your own drain and size it appropriately. Depending on the commodity and the local Codes for contamination, you may also want to consider connecting it to a closed Pump-Out system
prognosis: Lead or Lag
RE: Centrifugal pump - suction reducer - drain required
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: Centrifugal pump - suction reducer - drain required
RE: Centrifugal pump - suction reducer - drain required
Is it a good idea? probably not. Why -
1) as noted before size is normally pretty small on a casing drain
2) Any dirt sitting in the bottom of your pipe then goes through the pump
3) You then need to pipe your pump drain and put a valve on it otherwise with a plug you risk crossing the threads and needing to get a new pump casing - much more time and expense compared t putting a drain point on
4) The pump drain will be much lower than your pipe - even harder to get a slope on it back to the drain point or even get a bucket / container under it
5) Your new pump might not come with a drain (as noted they are optional) and then you're stuffed.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Centrifugal pump - suction reducer - drain required
The pump casing drain is usually small sized for draining the pump volute.
RE: Centrifugal pump - suction reducer - drain required
Process operators both love and hate casing drains. While insuring complete pump drainage and increased prepping flexibility, they are also potential leak points and could be additional fugitive emissions points. By design, they are usually small diameter and easily plug up.If the drain is routed to an open chemical sewer, it is also an additional entry on the cap and plug list.
Typical ANSI ductile iron process pumps would require a threaded connection to the bowl.Our specs would require the first nipple to be xxs in order to maintain the corrosion allowance at the threaded connection. This makes the plugging issue worse.
API pumps would require a socket welded connection to the pump bowl. This would also require a flange or union to allow for pump casing removal.
Retrofitting a casing drain requires the casing to have a boss cast in at the drain location.
As everyone has pointed out, while there are pros and cons of casing drains, but you almost have to have them on top suction pumps.
RE: Centrifugal pump - suction reducer - drain required
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Centrifugal pump - suction reducer - drain required
RE: Centrifugal pump - suction reducer - drain required
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way