Flex PVC

[coryatjohn]

Today I "plumbed" my vacuum system. Instead of the normal schedule 40 rigid PVC (2"), I used "Flex" PVC. It was quite easy to use and being flexible, allowed me to route the lines to the four zones without using elbows (except at the flange).

Flex PVC can be cut with a utility knife and bonded using the normal PVC cement. It's rated the same as regular PVC.

http://flexpvc.com/cart/agora.cgi?product=Flex_PVC_By_The_Foot

[myxpykalix]

I've never used this stuff and someone like Brady would have a better sense for whether it might collapse due to the suction or not...:confused:

[dana_swift]

John, you can read in some of my older posts where I used industrial 3/4 inch garden hose for a high vacuum hold-down and its still running well today with the original hoses! The thick-walled hoses with the nylon mesh will not collapse on themselves with 29" Hg vacuum! Once I discovered that, they became my primary flex-link for vacuum applications.

How high of vacuum are you pulling on the PVC flex?

D

[coryatjohn]

It would be impossible for the flex PVC to collapse under a vacuum. It's got a stiff spiral core of some very tough material (hard to cut with a utility knife) surrounded by some sort of rubbery stuff with an outside shell of PVC. For the 2" flex pipe, it's possible to bend to a radius of about 2' without any problems.

I would bet that this flex PVC would work well for air under pressure too. It isn't made with anything that can fracture.

Re: Dana - I'm pulling about 135 inches, at least in theory. I haven't installed the gauge yet.

[dana_swift]

John you will do well with the PVC.. its big advantage is lots of cross sectional area. Flow will be no problem.

FYI- I checked, 135" H2O is about 10" Hg.

The flex PVC is a good idea, if my garden hoses ever wear out, I may try some :)

D

[Brady Watson]

The flex stuff is fine for vacuum. The only detrimental aspect being lack of rigidity when it comes time to counteract the forces applied to turning the 2" ball valves on & off when you open/close zones. This may not be a huge deal if you use gate valves, so keep that in mind. If you use a traditional SB vacuum manifold configuration, the flex stuff isn't ideal...

-B

[coryatjohn]

The flex stuff is fine for vacuum. The only detrimental aspect being lack of rigidity when it comes time to counteract the forces applied to turning the 2" ball valves on & off when you open/close zones. This may not be a huge deal if you use gate valves, so keep that in mind. If you use a traditional SB vacuum manifold configuration, the flex stuff isn't ideal...

-B

I "rolled my own" configuration. I don't remember seeing the traditional SB setup so I don't know how different mine is. It seems pretty rigid though.

[coryatjohn]

I have my gauges hooked up now. Maximum inches Hg: 14. The relief valve lowers that to 11.5" which is the usable vacuum.

[Brady Watson]

Don't forget to filter your relief valve...

-B

[Greybarn]

How do you filter the relief valve?

[coryatjohn]

How do you filter the relief valve?

I put the relief valve on the "dirty" side of the system. In theory, a clogged filter would cause the relief valve to fail but the odds of the filter ever clogging are extremely remote. I have a gauge on both clean and dirty sides so I will be able to see when and if the filter starts to get clogged.

Here's a picture of the manifold: (mounted on the right-front)

http://www.usnaviguide.com/shopbot/manifold.jpg

Note the large blue cylinders. They are the filters. The aluminum tube on the right (horizontal) is the relief valve.

Here's a picture of the underside of the table showing how the flex PVC made the job a lot simpler.

http://www.usnaviguide.com/shopbot/flexpvc.jpg

[myxpykalix]

John that's awful fancy for a "newbie" but the one glaring omission i see in your pictures?.....NO SAWDUST!:eek:

That looks great. Have you done anything with your indexer yet?

[coryatjohn]

Jack,

I haven't had a chance to work with the indexer yet. I'm still learning the 2D+ stuff. I'm mounting it on the right side in the Y direction which will take some creative engineering to accomplish. Lots of stuff to do, figure out and learn.

[Brady Watson]

Professional setups run filtration on the BOV's...I'm sure you'll be fine. Setup looks nice!

-B

[myxpykalix]

When you get things all worked out let me know and i'll teach you how to do this........:eek:

[coryatjohn]

Brady,

Thanks for the thumbs up!

I used the vacuum system yesterday for the first time and it worked great. It's really an amazing innovation.