Sizing outlet for vacuum and pressure relief

[Tōtōchtin]

Most vac relief valves I can afford have 1/4" outlet. For low pressure relief valve seems 3/8" is the most popular. Im looking for a threaded outlet on pressure relief so that I might hook up a 2" collapsible hose to the outside. Has anyone figured out the math for a 15gal 5500w element minimal vent size. I'm working with a TBI so I need more safety backups then most.
Tōtō

[Dancing4dan]

Hey Toto what is it you are building? Is this a still with a thumper? Steam distillation system?

[Tōtōchtin]

Both, I am building 3) 15gal, 1) 7.5 gal. The 7.5 and a 15gal keg I want to set up as a steam generator or boiler. The other 2) 15 gal as retort/thumper. The last 2 are also to be used as boilers. Depending on what I'm up to. 3" column/riser and condensor, with 2" steam pipes all the way to the bottom of thumpers.
Why?
Tōtō

[zach]

I have pressure and vacuum relief valves on my steam generator keg, I use for stripping. I'm not a fan of relief valves on the still directly . Problems include potential plugging from solids in the boiler and a flammable discharge. I believe a manometer is a better solution if you feel a relief is needed.

I use a 1/2" stainless check valve for a vacuum breaker that opens at 1/2 psi . It has teflon seats.



I use a steam rated relief valve for the steam generator. With 5500 watt input to a boiler, the minimum required steam capacity is 19.5 lbs/hr. The smallest steam valve I could find is 3/4" with a rating of 290 lbs/hr and 5 psi set point ( made by Apollo). I use this valve on a keg with modification, that I tested filled with water to 10 psi. I have a 100,000 btu propane burner and the math works for this valve with steam.

https://www.grainger.com/product/APOLLO ... tics=FM:DC

[Dancing4dan]

Both, I am building 3) 15gal, 1) 7.5 gal. The 7.5 and a 15gal keg I want to set up as a steam generator or boiler. The other 2) 15 gal as retort/thumper. The last 2 are also to be used as boilers. Depending on what I'm up to. 3" column/riser and condensor, with 2" steam pipes all the way to the bottom of thumpers.
Why?
Tōtō

I’m not a fan of commercial PRV or VRV. Cost and usually to high a set point even at minimum.

A manometer will function as both.

My steam still has a manometer on the upper end of the steam arm as well as a DIY PRV on top of the boiler. A simple PRV built on the same principle used on kitchen pressure cooker is what I used.

[shadylane]

My steam still has a manometer on the upper end of the steam arm as well as a DIY PRV on top of the boiler. A simple PRV built on the same principle used on kitchen pressure cooker is what I used.

I call that wearing a belt and suspenders to keep your pants from falling down.
Ya don't want to have an accident while committing the crime of distilling and being exposed.

[Dancing4dan]

My steam still has a manometer on the upper end of the steam arm as well as a DIY PRV on top of the boiler. A simple PRV built on the same principle used on kitchen pressure cooker is what I used.

I call that wearing a belt and suspenders to keep your pants from falling down.
Ya don't want to have an accident while committing the crime of distilling and being exposed.

Ever try to run with your pants around your ankles?

[shadylane]

Ever try to run with your pants around your ankles?

Once upon a time and I got out of shotgun range damned quick.

[Yummyrum]

Ever try to run with your pants around your ankles?

Once upon a time and I got out of shotgun range damned quick.

However ,

A manometer will function as both.

My steam still has a manometer on the upper end of the steam arm as well as a DIY PRV on top of the boiler. A simple PRV built on the same principle used on kitchen pressure cooker is what I used.

Good advise D4D
To be sure , to be sure .

[Tōtōchtin]

I plan on a 12" x 2" riser to a manifold for my prv and pressure gauge. This can be added to any of the kegs. I was going to put the vacuum breaker in a steam pipe/riser and have a ball valve to atmosphere on steam generator.

I can buy 5) 1/4" 5 psi prv for $25 US. I was thinking about installing them on 5 tees inside a clear poly box that I can weld a 2" plastic barb onto . That would seem to work,if all 5 pop that would give me over an inch diameter exit. What's wrong with this idea?
Tōtō

[shadylane]

Theoretically during a puke 5 cornels of corn could plug up each of the five 1/4" PRV's
I'd recommend one store bought PRV and a manometer that was 1/2" diameter or bigger.

[Tōtōchtin]

Manometer parts I bought a while back. I've used them a lot adjusting gas pressure. I still can't figure out how you use them to measure liquid levels. That will be one of the first things that I'll check with it.
Tōtō
I'm now leaning towards a 3/4" prv that I'll use a copper to 1.75" PVC fitting that I'll attach a 2" collapsible hose to.

[shadylane]

A manometer is easy to make, all that's needed is clear plastic tubing, some fittings and ingenuity.
Plastic is bad for distilling, but Ok in this case, due to how and where it's used.
One side of the manometer connects to the boiler, the other is open to the atmosphere.
The measurement is the differents between the liquid levels.
A water filled manometer is extremally accurate, effective, cheap and is also a pressure and vacuum relief. A 12" tall water filled manometer accurately measures upto 0.43 PSI, just right for a boiler driving a packed column or several plates. For steam distillation a 3 to 6 foot tall manometer gets the job done.

[Tōtōchtin]

I have used them for years . For regulating gas pressure to tuning 2 carbs.About a year ago I bought the parts, still looking for that heavier than water medium. Measuring atmospheric pressure/ back pressure I can relate to. Measuring changes due to volume in a container is what I'm having trouble with. It might be once I sit down and watch this in action the light bulb will fire off.
As always thanks for your advice.
Tōtō
.

[shadylane]

Don't let the simplicity, of what's being done cause confusion.
Just do it, then figure out what has happened.

[Tōtōchtin]

I have pressure and vacuum relief valves on my steam generator keg, I use for stripping. I'm not a fan of relief valves on the still directly . Problems include potential plugging from solids in the boiler and a flammable discharge. I believe a manometer is a better solution if you feel a relief is needed.

I use a 1/2" stainless check valve for a vacuum breaker that opens at 1/2 psi . It has teflon seats.



I use a steam rated relief valve for the steam generator. With 5500 watt input to a boiler, the minimum required steam capacity is 19.5 lbs/hr. The smallest steam valve I could find is 3/4" with a rating of 290 lbs/hr and 5 psi set point ( made by Apollo). I use this valve on a keg with modification, that I tested filled with water to 10 psi. I have a 100,000 btu propane burner and the math works for this valve with steam.

https://www.grainger.com/product/APOLLO ... tics=FM:DC

I was just going to buy the same pvr from Grainger, until the notice that said I was buying an pvr not safe for drinking water lines. Have yet to run into a stainless steel pvr.
Tōtō

[zach]

The bronze construction might be the reason it is not rated for drinking water. With clean water in the boiler I judge the risk as minimal. I drain the boiler after each use. I would not use this prv on ethanol vapor.

The valve has a certified rating for steam, and can be found on boilers used in industry.

You can find cheap stainless prv's made in china, with no ratings . To find a stainless prv with a capacity rating , get ready to open your wallet. They exist, but they can cost 10 times more than this valve.

[Tōtōchtin]

I agree there are not many options out there. I think I need to upgrade my manometer. I was shocked Grainger industrial had the best price with shipping for this model.
Tōtō