Home made high pressure pump
Posted: Fri Mar 05, 2010 3:08 pm
Well, in another thread of mine I mentioned my home made hand pump, and a few people expressed some interest. I'm at school so I can't upload any pictures or anything, but I'll do my best to describe it.
The barrel of the pump is made of 1/2" drawn copper tubing. Check out http://www.copper.org/Applications/plum ... ble3a.html for working pressure ratings. The tubing actually has an inner diameter of around 9/16", which is almost exactly a half of the inner diameter of my bike pump. I can get about 200 psi out of my bike pump, so I should be able to get 800 with this home made one. I don't ever plan to go that high, though.
I made the plunger out of pvc turned on the lathe. I use some 1/2" O.D. steel pipe to connect the plunger to the handle. If you've ever taken a bike pump apart, you'll know that the seal on the plunger also acts as a one-way valve. It's quite simple, but hard to explain without a picture.
The bottom of the pump is made with brass fittings. The bottom one-way valve is made with a valve stem. I'll definitely need some pictures to describe this part.
The pump works, but it takes a long time to pump anything up. One of the problems is that you need an o-ring of the perfect diameter if want it to act as a one-way valve. If you take apart the top of a bike pump you will under stand this. My o-ring is a little small, and I have to occasionally stretch it out. Sometimes it seems like it doesn't seal until I've completed a significant portion of the stroke. So far, I've used it for pressure testing, but I haven't actually launched a rocket with it yet.
Anyways, it's worth a try to make one if you can't afford those ~$200 3000psi hand pumps on the internet, or if you're like me and just like to make things on your own. If you do make one, be safe! Make sure you stay well within the ratings of your components. There is never a whole lot of energy in the pump, since it's volume is so small, but it is right between your legs.
I'll try and get some pictures up this weekend.
The barrel of the pump is made of 1/2" drawn copper tubing. Check out http://www.copper.org/Applications/plum ... ble3a.html for working pressure ratings. The tubing actually has an inner diameter of around 9/16", which is almost exactly a half of the inner diameter of my bike pump. I can get about 200 psi out of my bike pump, so I should be able to get 800 with this home made one. I don't ever plan to go that high, though.
I made the plunger out of pvc turned on the lathe. I use some 1/2" O.D. steel pipe to connect the plunger to the handle. If you've ever taken a bike pump apart, you'll know that the seal on the plunger also acts as a one-way valve. It's quite simple, but hard to explain without a picture.
The bottom of the pump is made with brass fittings. The bottom one-way valve is made with a valve stem. I'll definitely need some pictures to describe this part.
The pump works, but it takes a long time to pump anything up. One of the problems is that you need an o-ring of the perfect diameter if want it to act as a one-way valve. If you take apart the top of a bike pump you will under stand this. My o-ring is a little small, and I have to occasionally stretch it out. Sometimes it seems like it doesn't seal until I've completed a significant portion of the stroke. So far, I've used it for pressure testing, but I haven't actually launched a rocket with it yet.
Anyways, it's worth a try to make one if you can't afford those ~$200 3000psi hand pumps on the internet, or if you're like me and just like to make things on your own. If you do make one, be safe! Make sure you stay well within the ratings of your components. There is never a whole lot of energy in the pump, since it's volume is so small, but it is right between your legs.
I'll try and get some pictures up this weekend.