Looking for vacuum gauge

[brewmeister13]

As the title says, I'm looking for a vacuum gauge to add to my RIMS mash tun. The problem is most of the ones I'm seeing are rated at a max temp of 140. Some are as high as 160, but that's still too low for me. Anyone out there have a suggestion on what they're using?

Also, I'm not looking to break the bank on this. I saw one that would work, but it was $400. Not going to happen.

 

[ajdelange]

I'm not sure exactly what the application is here but vacuum is a pretty good insulator so I would expect that you ought to be able to rig a piece of tubing between the point at which you wish to measure the reduced pressure and a gauge that is rated at less than 140 °F. Think about the pigtail on a boiler's pressure gauge.

 

[brewmeister13]

I'm not sure exactly what the application is here but vacuum is a pretty good insulator so I would expect that you ought to be able to rig a piece of tubing between the point at which you wish to measure the reduced pressure and a gauge that is rated at less than 140 °F. Think about the pigtail on a boiler's pressure gauge.

I was hoping to use a T directly after my mash tun's outlet valve, with the vacuum gauge in the top and wort flowing to the pump through the other end. I'm looking to use it to better control my flow rate in my RIMS while mashing and reduce the compaction of the grain bed, while flowing at the maximum rate possible to maintain temps and also to raise them more quickly. I assume at this location a 140ºF rating wouldn't work.

I'm not familiar with the pigtail on a boiler's pressure gauge and am pretty mechanically inept. I was also electrically inept until I built my own control panel, though, so I can be taught. Can you elaborate on how that would work?

 

[ajdelange]

I was hoping to use a T directly after my mash tun's outlet valve, with the vacuum gauge in the top and wort flowing to the pump through the other end.

Connect a piece of thick walled flexible plastic tubing to the side arm of the T. Route the other end to any convenient location a foot or so above the maximum liquid level in the tun and connect the gauge to it. Liquid will never rise in the tube above the maximum level in the tun and the remaining tubing, being a pretty good insulator, will not transfer the liquids heat to the gauge but the gauge will read the pressure at the T.

 

[brewmeister13]

Thanks AJ! It's definitely the route I'll take if I can't find a gauge that can handle the heat. It would, however put the gauge about 5 feet up and give my girls a nice handle to pull on (not that they would, but I tend to be slightly paranoid about safety with my designs).

Anyone using a gauge without using an extension to bring it above the water level?

 

[jddevinn]

I don't really understand the application...... but

http://www.mcmaster.com/mv1459975500/#3967K51 -40 to 200 °F Ambient 0 to 250 °F process

http://www.mcmaster.com/mv1459975500/#38605K1 Environment temperature range is -40° to 140° F and process temperature range is -40° to 212° F.

 

[day_trippr]

The application is to provide a method to determine if the pump is pulling too much volume for the bed to sustain before sticking.

In gravity flow situations (ie: no pump involved) one can use an open ended sight gauge coupled to the outflow port: if the sight gauge level drops precipitously it implies the bed is starting to stick. Can't use that with a pump because the pump will just suck the sight gauge down as it has less resistance than the mash bed, even if the wort is flowing freely...

Cheers!