Pump Pressure Not Enough ( SEREMBAN JOB )

This is another common issue
A contractor called and inform that pressure not enough , when earlier given was

a) Given
Capacity : 20 m3/hr at 42 m Head ( 4.2 Bar )
Pump Speed : approx 2100 rpm( slurry pumps )

b) Offered pump with same operating parameter and
same operating speed

c) later called and say need to operate at 6 bar

d) This is an indication that the user is not aware or not knowing what is his
requirement , which is 6 bar

e) what can be done

1) as pump is belt driven . adjust the pulley diameter to the required speed
and with reference to pump curve , there has been cases of people guessing the
speed and do many changes before arriving at the required speed and head

2) the motor 15 hp was designed for working pressure of 4 .2 bar at 2150 rpm
therefore the motor has to be upgraded to the required BHP ( 18.5 kw ) .Again ,remember
to refer pump curve

Above is a very simple issue , but the first thing that come to the user's mind

" hey . your pump lousy man , can only reach 4 bar "

" your motor too small lah ..that is why cannot reach 6 bar ''

What is being highlighted here is that . if the User knew what he wanted and
size the pump correctly . there is no waste of time doing further modification which
also incur additional cost,,,

Specifying Pump Head or Discharge Pressure

This has always been an issue all the while .Users tend to give pump head without actually determining the correct discharge head .For convenient purpose ,we will assume the head as
correct and this often leads to problems like motor tripping etc

What will happen ?
When the actual system head is 30 M instead of 60 M , the pump will be operating on the
extreme right of the curve ,maximum flow and low head ( 140 m3/hr at 30 m instead of
90 m3/hr at 60 M)

The result
a) 90 m3/hr at 60 M, the BHP is approx 40 Hp
b) 140 m3/hr at 30 M , the BHP is 55 HP

For the case ,you can either trim the impeller to smaller diameter
or Throttle the discharge valve ( never throttle the suction line )

This pump is open Impeller Slurry pump and supplied with 60 Hp motor 2900 rpm
A 40 hp could be used if the head is 30 M ( 90 m3/hr at 30 M

Take note the power difference

It must be emphasize that giving the actual operating head is extremely important
much saving can be made from

a) smaller pump being used
b) Pump can operate at 1450 rpm instead of 2900 rpm if head is low ,lower wear& tear
c) smaller motor Kw and in long run energy saving
d) long term lower maintenance cost for smaller pumps

Pump Certification

There are various certification for pumps and and equipment
As an example

ATEX
a) Some Plant may require ATEX Certification from Europe and these are pumps are not
common .The prices can be extremely high and delivery is also very long period
EBSRAY PD pumps can be supplied with ATEX, details fo Atex can be obtained from the websites


b) Bomba (Malaysia )
For Fire Fighting application ,pumps supplied must be under the BOMBA approved list
and EBSRAY Streamline Series is under Bomba Approved List

c) Lloyd'S REGISTER QUALITY ASSURANCE

Allen Gwyness pumps are certified under Lloyd's Quality Management System

And there are many others Standard of requirement say API for Oil and Gas users

Food or Pharmaceutical Companies may require Traceability Certifcate by manufacturers
Our Alfa Laval Pumps does come with this on request and chargeable

I will continue to update on this Topic