SpudFiles

Well my parent's have banned me from obtaining a fridge compressor due to the fact I might electricute myself or blow a fuse and start a fire which is a valid reason in my eyes. So I thought I'd make myself an ultra high pressure pump. I'm talking 600-800psi.

To get a check valve that could withstand that sort of pressure, it would cost alot and if I used a low pressure valve, I might get a blowout out BTB did and possibly kill myself... So I came up with this idea. It's a floating o-ring check valve. My guess is it that would be very hard for it to fail and it could handle alot of pressure with ease.

...and not to mention it being stupidly simple to constuct.

I'm going to use a galvanised T with the main check valve bolt mig welded in place. To get the bolt in the perfect spot will be the hardest part. I'll construct the whole check valve, sit in it place inside the chamber, do a tack, make sure it's correct and then really go over it with a thick bead of weld.

Please tell me what ya reckon guys

oh come on.. you can electrocute yourself with any electrical appliance... your parents are overprotective

if you do the wiring properly it's safe - that's it

Yeah I know I tried explaining my case to them but it fell upon deaf ears... My mate reckons that he couldn't get this compressor past 300 or so psi so it's pretty useless.

lol maybe he told you so to get your compressor....

I don't know why people encounter so many problems with fridge compressors - are they cursed or something ? Apparently I should be happy that mine works flawlessly... you are the third or fourth person who tried building one and encountered some problems

I leave commenting on design of your pump to someone who has some experience with stirrup pumps

Well this compressor works fine but I think it's just really old.. Hence why it's struggling to get past 300+ psi...But I'll see what I can do with it anyway.

What pressures are you getting from your pump anyway mate?

I regularly use 500psi in my launchers from my fridge compressor, and even then i can hear that its not maxing out. So yea, a bit odd that it cant do more than 300.

That's wrong with using a schrader? It would take a lot to make one fail.

the highest pressure I've ever used was 500 psi... I assume that it could go much higher but an airhose bursted on that occasion
becasue of this I rarely go past 450 psi and normally I use it at 350 psi

My current gun has rather large chamber ( 1.5 cm ID by 110 cm ) so it takes time to pump it up to really high pressures as the pump slows down a bit as the pressure increase.
I am planning to improve the compressor a little, buy an airhose or a hydraulic hose rated to insane pressures and add a tank or another fridge compressor to increase flow.

so to put it the more understandable way: if this pump get a 22mm main cylinder, your valve would have to hold about 1140kg on 500psi.
that means you have to trust your weld to death.

Nice to see everyone commented on the check valve idea hahaha. The schrader valve would be good but I don't know where to find a bolt on/threaded valve. Plus, I like to be inovative and use what I have to make something phenominal that's never been done.

I reckon the pump would be good for my low volume guns. My mate was using it to fill a fire extinguisher to 300 odd psi... I'd be struggling too if I had to work that hard....

Hey Mitch.

Time to dig out the calculator again eh?

1/2" type L has an id of .545". At 800psi this will require a force of ~187 pounds. (85Kg)

1/2" type M has an id of .569". At 800psi this will require a force of ~203 pounds. (92.3Kg)

Consequently, this is also the amount of force trying to "remove" your check valve.

A few comments on the design;

You need to incorporate something to limit the travel of the o-ring on the down stroke. If it moves too far, it might jam up and not come back to seal. (Pump handle in the face syndrome.)

I like serviceable stuff, could you weld a nut into the bottom? This would allow you to "unscrew" your check valve to replace the o-ring.

Best of luck.

Yeah definately Geppito, serviceable equipment is always good when you make alot of mistakes like me . To limit on how much the o-ring moves, i'll make the grooved washer on the bottom, only a fraction smaller then the top sealing washer so it flexes only enough to break the seal and allow the air through. The nut on the idea sounds like a top idea as opposed to welding the bolt straight on.

Thanks alot for the help mate,

I really appreciate it