DIY Pressure relief valve

[someone]

Hi,
Trying to make a new VM column still with a somewhat unconventional design. Was thinking that if I put a "Y" at the top of the column with a gate valve on both sides I could have full control over the reflux ratio (0% - 100%) by opening or closing the gates as required. One arm of the "Y" would be the take-off, the other arm of the "Y" would continue through a Leibig condenser and then back to the column below the "Y". Now the problem I have is this design would be a closed system (also known as a bomb), so was thinking if I run a tube out the top of the "Y" down about 1m (just over 3ft) then back up 1m (just over 3ft) (end open to the atmosphere) and half fill this with water it would act as both a pressure relief valve and with a clear piece of tubing could also make a pressure gauge. The gauge could read up to 10kpa (209lb/ft2) (not much pressure) before the water would be pushed out the top allowing any further pressure to be released (and have me turning the still off).

I'm interested to see if this design equalizes the amount of condensate forming with the amount of vapor forming (ie. should have very low pressure - just need to ensure that the cooling capacity of the condenser to the reflux arm is safely bigger than the element). Whilst I'm aware that for obvious reasons (ie. exploding stills) that it is unwise to allow pressure to build up, I consider 10kpa max. via this relief valve (209lb/ft2), to be a safe amount (about 5% of the pressure in domestic water pipes and 10% of atmospheric pressure). Would use water first to observe the pressure variations before trying with sugar wash.

Does anyone know if this pressure relief valve would work, or has fitted pressure gauges to in a running still to see the pressure variations in different parts?