PD Pump inlet pressure oversized.

[Brightkam]

Hi all,

please I need help, I resently procured a positive displacement pump with a stroke adjustment for a varibale output discharge of brine solution. The inlet pump pressure should be atmospheric pressure but it was over size as one bar.
Plunger diameter = 85 mm
Minimum stroke length = 3 mm
Minimum strokes per minute = 27
This gives an absolute minimum flowrate of 27.6 Litres/hour.
This is the absolute minimum that the pump can deliver.
The discharge pressure is 4 bar and 1 m3/hr flow rate, a pulsation damper was installed on the pump.
the pump is already installed and there is no room to raise the tank the pipe work also insulated and trace heating very difficult to increase the diameter of the pipe work, infact the cost for pipe rework is more than precurement of new pump how ever we are out time.

 

[LittleInch]

So what exactly is your problem / issue?

You haven't asked a question.

As long as your discharge pressure is always greater than 1 barg ( min 1.5 barg) you shouldn't have a problem, it just means the pump is doing less work than it was designed for, but so long as it is doing some work, then you have control over the flow rate, which is what I assume you want with a pump that seems to have a very large turndown (36:1).

If for whatever reason your discharge pressure fell below 1 barg, you could easily get a lot more flow through the pump than you want.

Is this what you wanted to know?

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[micalbrch]

Mmmmm, 27.6 L/hour minimum flow and 1000 l/hour required? That is a multiplier of 36. Hard to believe that the pump will work properly with 36 times the stroke rate.

 

[Brightkam]

Thanks All,
The problem now is the client is worried on pump higher inlet pressure,because there 4 variable discharge from this brine pump to increase the salinity of dowstream seawater flow the the pump max flow is around 500 l/h. and Minimum stroke length is 3mm therefore the minimum flow rate that the pump can generate is 99.4 litres per hour

THE client expect 133 litres of brine when 4 streams are operating and the max 2.5 g/l of chlorides are required

How can i acheived this flow without increase line or cahnge the pump.

 

[LittleInch]

Ok Stop there.

Please draw a sketch of your system and please be consistent. first you have 27 litres an hour min, now you suddenly have 99.4.

First you have max of 1000l/hr, now you have 500l/hr.

First you have discharge pressure of 4 bar, with 1 barg inlet, now you have 4 variable at unknown pressure.

Present clear consistent data otherwise you won't get good response.

Please come back to us with a straightforward consistent story. Then you might get some help.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way