While this spunding valve may look a little clunky compared to the more common brass one with the poppet valve on the end after a lot of testing we believe this to be a superior design.
The diaphragm valve is much more accurate and allows for extremely precise adjustments of the outlet pressure.
As the valve will not be damaged by liquid passing through it but the gauge will be you can set the venting pressure to what you want and then remove the gauge preventing accidental damage.
This makes it perfect for doing fermenter to keg and keg to keg transfers under counter pressure without having to worry about overflow damaging the gauge.
A spunding valve is an adjustable pressure relief valve with a gauge attached to show internal vessel pressure.
They are most commonly used to do keg to keg transfers of carbonated liquid under pressure.
To do this attach your regulator to the full vessels gas inlet post (fermentasaurus for instance) then join the 2 liquid post together with 2 liquid disconnects and a length of beer line.
Attach the spunding valve with a gas disconnect to the empty vessel (mini keg for example).
Set the pressure on the regulator to 12-15psi and then unwind the spunding valve until gas begins to vent. Set pressure to 8-10psi on it and the liquid will transfer across under pressure without losing any carbonation.
It can also be used to set a release point for pressure in the fermentasaurus, this is very useful as you can set it to approx 12 psi (depending on fermentation temperature) and once finished the beer will already be carbonated (you will need to either chill the fermenter to allow the liquid to hold carbonation while you bottle or use the method outlined above to transfer under pressure to stop it losing the carbonation while warm though.