Self Venting vs Self priming, are they same concept?

[billbusy]

Self Venting vs Self priming, are they same concept?
When you look at a cross section of a centrifugal pump, how to determine if it is Self Venting / Self priming?

Thanks.

 

[bimr]

Look at the Gorman-Rupp centrigual pump for a self-priming pump design:

https://www.youtube.com/watch?v=XMThI7x5bGs

Self-venting pump - a pump whose casing can be flushed of entrained gas by simply opening its suction and discharge control valves and rotating the shaft manually prior to starting. The pump casing does not have a vent connection. In a multistage pump, only the first stage volute needs to be self-venting.

API Standard 610 considers a pump to be self-venting "if the nozzle arrangement and casing configuration permit adequate venting of gases from the first-stage impeller and volute area to prevent loss of prime during the starting sequence."

http://centrifugal-pump.org/glossary_S1.html

 

[Artisi]

No they are not the same.
Self venting means that air has a means of escaping the case so as not to airlock the volute - although sometimes not all that successfully, whereas selfpriming are designed the remove the air by the design of by air pump / vacuum pump while at he same time lowering the pressure in the volute so flow from the source can be achieved by atmospheric pressure.
Suggest a bit more research on the net looking at self-venting pumps and selfpriming pumps.

Most top centerline discharge centrifugal pumps are self venting - meaning that air can escape the volute - this doesn't mean they will self prime as the system in which the pumps are installed will govern this.

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.)