Flow regulator for vacuum pump

[jiyoo]

I'm looking for a flow regulator for the vacuum pump.

I'm sampling the particules from the combustion source with filter and vacuum pump. However, the pressure drop is getting increased so, I have to monitor and adjust the valve for vacuum pump. Is there any regulator for the vacuum pump then I don't need to keep looking at the valve and pressure?

The system is..

1)Combustion source -> 2)filter -> 3)valve -> 4)vacuum pump.

I would like to put the regulator between filter.

Thanks in advance.

 

[jiyoo]

In Addition to,

The valve should being opened when the pressure is getting increased.