Comparing Hand Pump Performance: Brand A vs Brand B

[haruko]

I'm currently doing a testing on hand pump from 2 different brand. Let's say Brand A and brand B.
Brand A hand pump is 20cc/cycle with maximum pressure 350 bar, Brand B hand pump is 25cc/cycle with maximum pressure 350bar as well.
1. brand A hand pump easily pump up to 92bar, but after i tried it for about 30 mins, its pressure only increase to 98bar. While brand B hand pump can be easily pump up to 100bar, and then take about 30mins to pump it up to 110bar. What do you think? Is it the quality of the hand pump or its have something to do with the displacement of the hand pump?

2. Is the displacement per cycle affected its performance?

Can anyone give me any opinion?

 

[drankin]

I'm currently doing a testing on hand pump from 2 different brand. Let's say Brand A and brand B.
Brand A hand pump is 20cc/cycle with maximum pressure 350 bar, Brand B hand pump is 25cc/cycle with maximum pressure 350bar as well.
1. brand A hand pump easily pump up to 92bar, but after i tried it for about 30 mins, its pressure only increase to 98bar. While brand B hand pump can be easily pump up to 100bar, and then take about 30mins to pump it up to 110bar. What do you think? Is it the quality of the hand pump or its have something to do with the displacement of the hand pump?

2. Is the displacement per cycle affected its performance?

Can anyone give me any opinion?

You may have run out of fluid in the reservoir filling the line for your pressure test.

We use hand pumps in our shop all the time and I have seen this happen. Are these brand new hand pumps?

Are you pumping directly into a dead-headed gauge?

 

[haruko]

It is very difficult to pump while the pressure more than 100 Bar. because this is not two speed pump, it is only single speed and the capacity is 25cc per stroke, so you will feel very hard to pump. For example those high pressure hand pump maker, they will use 32cc for high speed low pressure; 1.6cc low speed high pressure, so the user would not feel difficult pump it.

This is the reply from supplier of Brand A. Can anyone explain this?

 

[haruko]

You may have run out of fluid in the reservoir filling the line for your pressure test.

We use hand pumps in our shop all the time and I have seen this happen. Are these brand new hand pumps?

Are you pumping directly into a dead-headed gauge?

No, it's not run out of fluid.
No, it's not a brand new hand pump.
No, we don't pumping directly into a dead-headed gauge.

 

[drankin]

Then it sounds like you need to turn up the relief valve which is simply a check valve with a heavy spring and screw or socket head adjustment. It's getting to 110 bar but pumping after that it just pushes the oil over the relief back to the reservoir.

 

[haruko]

Then it sounds like you need to turn up the relief valve which is simply a check valve with a heavy spring and screw or socket head adjustment. It's getting to 110 bar but pumping after that it just pushes the oil over the relief back to the reservoir.

that's no relief valve in this case...

 

[drankin]

that's no relief valve in this case...

You are telling me you have a hand pump without a relief valve? I've never heard of one. Sorry, I couldn't help you.