pressure reducer / flow restrictor - difference ?

[sm_jamieson]

What is the difference between a pressure reducer and a flow restrictor ? Surely they just reduce the bore.

The restrictor on my bar mixer inputs (for use with high pressure water) is a plastic disk with an O-ring on one side and holes round the perimeter on the other side. Is this doing anything fancy other than reducing the bore to a tiny size ?

In this application you need to maintain the pressure (for a high-pressure shower head maybe with smaller holes etc), but reduce the flow so that the input ports can be wider open so there is more leeway on the temp balancing.

Is there a better solution than using the supplier restrictors, i.e. some device elsewhere in the supply pipes ? What about just having the isolation valve half open ?

I don't think pressure and flow can be independant parameters.

Simon.

[srp]

A presure reducer ( like the one I fitted on the cold pipe on my shower) actively adjusts the amount of flow to maintain an even output pressure. It uses the force of the incoming water to control how much the valve opens. I used it because the boiler drops the pressure of the hot water output compared to the mains for some reason..

A restrictor ( I assume you mean like a tap?) reduces the flow a set amount. I guess it would be a bit like the difference between a resistor and a voltage regulator IC circuit in the electronics world. A resistor will drop the voltage but it will vary depending on the input voltage.

Correct me if i'm wrong though ;0)

Simon

[Rob Morley]

Just guessing - a pressure reducer will have some sort of spring- loaded valve in it, a flow restrictor is just a reduced bore. Both will reduce dynamic pressure, but a pressure reducer works better than a flow restrictor at lower flow rates because the pressure reduction of a flow restrictor is more affected by the flow rate.