Pressure Gauge for King Keg

[Job]

Hi all, my first post and I am new to brewing.

I have been investigating putting pressure gauges on king keg barrels following advice from this forum which states it is important to ensure positive (CO2) pressure at all times in the barrel during conditioning and consuming.

I had a look at the various custom built options online which looked expensive and all seemed to be a bit crude (PTFE tape, large fittings, mutliple connections, etc.).

I have subsequently had a play around with various fittings from ebay in order to achieve a permanent, low cost pressure gauge in a king keg lid and have succeeded.

The main points to remeber are the different fittings and how they work, e.g.:

BSPP (British Standard Pipe - Parrallel)
BSPT (British Standard Pipe - Tapered)
NPT (National Pipe Thread)

The main thing to take away is that NPT will not form a seal with BSPP or BSPT without PTFE (as the thread shape is not compatible). A lot of the barrel gauges available seem to have NPT fittings going into BSPP fittings and subsequently a lot of PTFE tape.

Also worth noting is that BSPT will fit into a BSPP AND a BSPT fitting and create a seal (two turns, dont overtighten, etc.)

Thus the only components required to add a pressure gauge to a king keg (or any other) barrel is a BSPT pressure gauge and a BSPP or BSPT 'bulkhead fitting'.

e.g. from ebay:

Pressure Gauge 50mm Dial 1/8 BSPT Vertical 15 PSI
Nickel Plated Brass BSP Bulkhead Fitting (1/8)

That is GBP6.95 + GBP3.12 = GBP10.07 delivered at time of writing

The 1/8" fittings obviosuly require a smaller hole - it can be done with 1/4 gauge and bulkhead fitting etc.

Also needed is a washer - a spare washer from an S30 fitting will work, or:
10 x S30 CO2 homebrew Injection Valve Washers

and if you dont have something to make a hole you could get something like:
Large Cone High Speed Steel Step Hole Cutting Drill Bit Set Cutter

Hope this helps someone. Photo attached...

 

[PenhowBrewer]

Hi Job

Thanks for the straightforward clarification. I had bought a gauge, but trying to work out what I needed to connect it in terms of bstp/bspp/npt threads, connectors and converters was doing my swede in!
I have ordered a bulkhead fitting, so I should be cooking on gas later this week

 

[Sandimas]

I ordered one off eBay - drilled a hole in the plastic lid slightly smaller then reamed it out so the gauge was a tight fit: job done

 

[kelper]

What pressures are you seeing? I'd like to get a gauge of the right range!

 

[Sandimas]

About 9 PSI after 8 days. Rises sharply in the first week then usually levels off.

Pressure gauge

• Sandimas
• Mar 4, 2019

 

[terrym]

What pressures are you seeing? I'd like to get a gauge of the right range!

You don't really need a pressure gauge on a plastic PB, they are more 'a nice to have'. You can manage the pressure in your PB without one, and provided you don't overprime or add too much gas the upper pressure will be what it is and by experience you will know not to add too much of either since it will take forever to dispense a pint. And in any case the PB relief valve should vent overpressure to protect the PB. And at the bottom end when the pressure gets to the point where the dispensing beer flow has almost dropped off it's time to reprime or regas.
But if you do buy one I suggest you buy a gauge that has a range of at least the pressure limit of the PB.

 

[kelper]

What's the pressure limit of a King Keg? When does the relief 'valve' go off? I guess it varies a lot, depending on the rubber band!

 

[terrym]

What's the pressure limit of a King Keg? When does the relief 'valve' go off? I guess it varies a lot, depending on the rubber band!

The limit should be stamped on the body. My basic PB is stamped 'Maximum Work Pressure 15psi' (actually they mean 15psig) . And yes the rubber band RV is a crude device. My guess is that its designed to vent just under the MWP, or it would do if I had designed it.

 

[Jason42]

Very useful thread. I had already decided to fit a pressure gauge but the original post gives me a shopping list,cheers for that:hat:

You don't really need a pressure gauge on a plastic PB, they are more 'a nice to have

I agree, but us engineers are totally obsessed with measuring stuff.

 

[terrym]

Very useful thread. I had already decided to fit a pressure gauge but the original post gives me a shopping list,cheers for that:hat:

I agree, but us engineers are totally obsessed with measuring stuff.

Maybe, but I was a chartered engineer in a former life and one of the things I learned early on was the KISS principle.

 

[Jason42]

Maybe, but I was a chartered engineer in a former life and one of the things I learned early on was the KISS principle.

A principal I have learnt well
But it does seem to be a simple solution to detecting leaks and monitoring the state of the barrel as much as the contents, especially for beginners like me.

“The optimist says the glass is half full
The pessimist says the glass is half empty
The engineer says why is this glass twice as large as it needs to be?
The art student says do you want fries with that?”

Anonymous.

 

[Hazelwood Brewery]

A principal I have learnt well
But it does seem to be a simple solution to detecting leaks and monitoring the state of the barrel as much as the contents, especially for beginners like me.

“The optimist says the glass is half full
The pessimist says the glass is half empty
The engineer says why is this glass twice as large as it needs to be?
The art student says do you want fries with that?”

Anonymous.

No,
The glass is only half full when filling it
Only half empty when drinking from it

I toyed with pressure gauges on my King Kegs, decided in the end it was one more place to develop a leak (as if they don’t have enough already!).

 

[Buffers brewery]

Being a fan of Heath Robinson I’m not a fan of “simple” . I have gauges fitted to both my KKs. They help me identify if I have a leak. They help me not to waste CO2 by over pressuring. They prompt me to recharge when the pressure is getting low. I don’t have a chartered engineer’s touch so need a bit of help when pressurising as (according to Boyle’s law) when the keg is full of beer it will only require a little squirt to achieve pressure but when it’s half empty a lot more. Anything that makes life easier I’m a fan. No offence @terrym:hat:

 

[BridgeBrew]

Just fit a Schrader valve, and use a digital tyre gauge to measure your pressure. That also gives you another port to add CO2.

 

[terrym]

Being a fan of Heath Robinson I’m not a fan of “simple” . I have gauges fitted to both my KKs. They help me identify if I have a leak. They help me not to waste CO2 by over pressuring. They prompt me to recharge when the pressure is getting low. I don’t have a chartered engineer’s touch so need a bit of help when pressurising as (according to Boyle’s law) when the keg is full of beer it will only require a little squirt to achieve pressure but when it’s half empty a lot more. Anything that makes life easier I’m a fan. No offence @terrym:hat:

If you have a leak you will lose pressure with or without a PI. If you have a gauge fitted how does that identify where the leak is? If you don't have a PI and have a leak you will notice that the dispensing pressure is lower than it should be. The outcome is the same, a soapy water test, unless its below the water line in which case you will see liquid.
And you can operate a PB without a PI to identify when to top up with CO2 the controlling parameter being dispensing pressure. This is what folks like me do, and it ain't complicated
There's nowt wrong with fitting a PI to your PB if that's what floats your boat but they really are a 'nice to have' imo.
And you don't have to be a chartered engineer or any other sort of engineer to operate a PB just someone with a bit of common sense which is what most folks should have, although one of my old maths teachers used to say 'common sense is a rare commodity' and I often think he was right.

 

[Buffers brewery]

If you have a leak you will lose pressure with or without a PI. If you have a gauge fitted how does that identify where the leak is? If you don't have a PI and have a leak you will notice that the dispensing pressure is lower than it should be. The outcome is the same, a soapy water test, unless its below the water line in which case you will see liquid.
And you can operate a PB without a PI to identify when to top up with CO2 the controlling parameter being dispensing pressure. This is what folks like me do, and it ain't complicated
There's nowt wrong with fitting a PI to your PB if that's what floats your boat but they really are a 'nice to have' imo.
And you don't have to be a chartered engineer or any other sort of engineer to operate a PB just someone with a bit of common sense which is what most folks should have, although one of my old maths teachers used to say 'common sense is a rare commodity' and I often think he was right.

Thanks for your kind words of wisdom @terrym . Common sense may be a rare commodity but so is a sense of humour perhaps? Note to self: don’t rib terrym.