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Suction and discharge pump nozzles diameter
Q: Why is the suction line of a pump of larger diameter than the discharge line? Why do we have “reducers” near the pump suction and discharge nozzles?
A: When comparing the differences in diameter on the suction and discharge pump nozzles, a number of considerations are taken into account.
The discharge nozzle size of a pump is sized to relate to the line velocity of the flow for which the pump is designed.
The suction nozzle size is usually sized one size larger than the discharge nozzle. Some exceptions are noted in the case of solids-handling pumps where the suction nozzle size is made the same size as the discharge nozzle so that particles that enter the pump can also exit the pump. This assumes that the impeller design in that pump will also pass the same particle size.
The reducer on the inlet side of a pump ensures that the velocity of liquid in the suction line is slowed sufficiently to provide a smooth flow of liquid with minimized friction losses in the line to ensure as high as possible an NPSH available from the system.
The increaser on the discharge side of the pump is designed to increase the pipe diameter from the pump nozzle to reduce the velocity of the liquid in the discharge line in order to reduce the total head the pump is required to develop to operate the system.
Here are more of the latest questions on: Pumps
Why are we experiencing anti-rotating device failures at an alarming rate?
We have three circulating water vertical pumps and we are experiencing anti-rotating device failures at an alarming rate. The discharge line is 72 inches. All the parameters have been checked and we are still clueless of the problem.
Pump Detail
Equipment description: Circulating Water Pump
Equipment Tag No. : CW-PP-002 (A/B/C)
Type: Vertical Flow Sump Pump
Model: 1800HV
Head: 17m
Capacity: 17280 m3/h
Shaft power: 971 kW
Speed: 495 rpm
Pump height:10m
Weight (pump): 30 ton
Weight (motor): 20 ton
Manufacturer: Shenyang Pump Manufactory, China
Is dynamic balancing important?
I have always been told that dynamic balancing is not as critical on impellers because as soon as the impeller is loaded, the water causes hydraulic imbalance. We have always balanced them down to NEMA standards anyway, but it would be nice to know for sure.
Does the velocity in the suction line need to be maintained?
In a new installation, the supplier has erected a suction pipe of 3 inches connected to suction nozzle of 4 inches in the centrifugal pump for slurry application. The general engineering practice says the suction pipe should be the same or one size larger than the suction nozzle of the pump. As per supplier, this arrangement was made to maintain slurry speed of >1.5m/sec. With this condition, we are having frequent seal failures. Please suggest whether this type of suction pipe sizing is acceptable. And is it required to maintain slurry speed in the suction side as given by supplier?
What are the disadvantages of putting a strainer on the discharge of a pump?
What are the disadvantages of putting a strainer on the discharge of a pump?
What is causing the strainer to choke?
We have an ammonia recovery system at our ammonia plant. Ammonia is recovered in a scrubber operating at 105 Kg/cm2 with lean water. Water is pumped through a PD pump. Basket type strainer is installed at pump suction line in vertical position. Chocking problem is frequently observed with this strainer with algae layer due to which pump flow reduces to minimum. What do you recommend?
