Introduction: DIY PVC Check Valve (for Membrane Pipes)

By fabricate.io

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Hey everyone! What follows is the first decently working version of a check valve for my very own set of membrane pipes.

For a bit of background: I needed a valve that would allow air to easily flow in one direction with very little pressure, but that would prevent air from leaking back out. I couldn't use a traditional bagpipe valve (the leather flap variety) because I really didn't want to have to go inside the duct tape bag I made, and purchasing a premade valve (e.g. a moose valve) would just be cheating!

My solution? A quick lowes trip and a few bucks worth of plumbing equipment. Check them out in the video below, or head on to the next step to get started!

Step 1: Acquire & Size the Parts

You will need:
  • 2x 1/2" to 3/4" CPVC couplings
  • 1/2" CPVC pipe (1.5")
  • 1/2" OD vinyl tubing (6+ inches)
  • Automotive grommet (see pictures for approximate shape)

All of this stuff is relatively easy to find... just go to the plumbing section of any Lowes and you'll find the adapters and pipe+tubing. The only strange part was the automotive grommet, but it lives in the washers/grommets section and you'll find it without too much worry. 

Preparation is similarly easy - just cut the vinyl tubing and the CPVC (with the CPVC a bit shorter than the vinyl) and poke some holes in the vinyl tubing to allow air to escape. 


Step 2: Assemble & Adjust

All that remains is to put everything together! The pictures are pretty self-explanatory. 

In the end, the grommet should be seated pretty firmly against its adapter coupling. You can adjust the force of the valve by compressing the two end couplings together... I aimed for something that felt roughly like breathing through a straw in one direction, with no air coming out in the other direction. 

For my application (membrane bagpipes) it was then just a matter of sticking it on the bag. I can adjust the sensitivity of the valve now without having to open the bag at all!

Hope this helps any future membrane (or DIY) pipers! If you have any questions, throw me a comment and I'll respond as best I can.