Pump Working pressure 1

[vecnaj1978]

Hello

I wanted to know what exactly the term Working pressure of Pump Means
What is casing working presuure of pump
How to calucalate the Working pressure in a closed loop chilled water pump system

we have a installation wherby the pumps are installed in the ground floor and pumping up to 35 floors

With each floor measuring 3.5 meters the total height of the building is 122.5 meters.

The return line back to the Pump suction is comming from 35th floor.

What working pressure of a pump should i select

please advice

regards

Najeeb

 

[bimr]

Maximum Working Pressure is usually defined by as the maximum pressure that can be developed at the discharge
flange under any operating condition.

For your application you first have to know what total head you need and at what flow rate. The static head requirement is often the main component of total head, how high do you need to get the water based on the level of the suction tank? The next important consideration is how much friction do you need to allow for, this depends on the length of pipes and their diameter. The sum of the static head and friction head will give you the total head. The total head and your flow requirement will allow you to buy the right pump.

http://www.pumpfundamentals.com/what is head.htm

 

[Artisi]

Are you asking,
1. what pressure the pump casing must withstand so that it won't fail?
or are you asking
2.what head the pump must be able to develop to maintain 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.)

 

[vecnaj1978]

Dear Artisi

i need to know what pressure the pump casing must withstand so that it won't fail?
also if possible
.what head the pump must be able to develop to maintain flow
regards
Naj

 

[petrochemical87]

In a closed loop pumping system the pump does not need to overcome any static head it only needs to overcome the frictional head loss due to pipes and fittings(this assumption is only valid when the system is full of liquid when you start the pump). You need to calculate the frictional head loss at the rated flow rate through the system and your selected pump should be able to provide this flow rate at the rated head. The maximum casing pressure can be the sum of static head of the system and the shutoff head of the pump.

 

[QualityTime]

Petrochemical87 is correct. You have a closed loop system that is full of water. Therefore the working pressure that your pump will work at will be the friction loss in the entire piping system at your desired flow. You will also need expansion tanks in your system cancel out the severe pressure spikes that you will encounter when the piping contracts due to the water getting chilled.

As far as for static pressure on the pump casing that is a different story. At a total building height of 122.5m this is equivalent to 174 psi static pressure. The pump casing (and piping) must be able to withstand this pressure.