PUMP DISCHARGE HEAD
PUMP DISCHARGE HEAD
(OP)
Dear sir,
Demiwater pump have 8m of suction head below storage tank, and pump discharge head is of 80m, in this case, is this suction head(8m) have to be included in a total head calculation of pump as to 88m.
Demiwater pump have 8m of suction head below storage tank, and pump discharge head is of 80m, in this case, is this suction head(8m) have to be included in a total head calculation of pump as to 88m.





RE: PUMP DISCHARGE HEAD
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: PUMP DISCHARGE HEAD
Pls refer to attached file for for this clarification.
RE: PUMP DISCHARGE HEAD
If the tank contains non-boiling liquid at storage pressure, the suction head will be higher than 8m.
See http://www.pumpfundamentals.com/tutorial3.htm and http://www.mcnallyinstitute.com/07-html/7-01.html
Dejan IVANOVIC
Process Engineer, MSChE
RE: PUMP DISCHARGE HEAD
As noted above, be very careful in your wording and read carefully the data given by you and the pump vendor.
Pump discharge head is exactly that. In many cases this could be taken as already including the inlet head.
Most pump data sheets or curves give you Developed Head in which to get the Discharge head, you add the inlet head. As emmanueltop says very well, use the same units and be consistent in the use of your units.
If what you mean in your OP is that the Pump developed or differential head is 80m, then you are correct, but need to add the atmospheric pressure (or whatever the absolute pressure is on top of the liquid) to the inlet and then convert to absolute pressure from the final discharge head.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: PUMP DISCHARGE HEAD
The sketch doesn't really clarify much other than there is 8 metres positive head on the pump. The 80 metre discharge head is still confusing -- is it 80 meters total head at the discharge (72 being developed by the pump Hd + 8 Hs+ = 80) or is it 80 metres developed by the pump to give a total of 88 (8+80=88).
OP - please clarify the 80 meters at the pump discharge - or do we assume it is the total head at the pump discharge? -- if yes - the answer to your question is "the total discharge head is 80m" and the sketch should say 80m total head.
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: PUMP DISCHARGE HEAD
System head = total discharge head - total suction head
See the example:
http://www.mcnallyinstitute.com/07-html/7-01.html
RE: PUMP DISCHARGE HEAD
Bimr, sorry but IMHO I'm not sure that adds anything. I've never heard of pump developed head called total system head before now or "friction head". Friction losses yes, but this example seems to be one persons take on a subject different to just about everything else I've ever seen.
Referring to negative feet head is also a new concept as is feet of head absolute or guage.
If you do it all in absolute then there is no confusion and pump developed head is quite clear - "system" could mean anything....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: PUMP DISCHARGE HEAD
RE: PUMP DISCHARGE HEAD
The pump fundamentals link is a bit more like it, but even that gets a bit too simplistic at times, IMHO.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: PUMP DISCHARGE HEAD
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.)