Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 1,768
Default Check Valve Plastic Valve

On Tuesday when I was putting my compressor back together the check
valve leaked noticeably. After several attempts to clean and polish the
faces to mate I gave up and dropped an O-ring into the valve to seal it
up until I get a replacement valve.

It got to bothering me though. In all the time I have owned the
compressor I don't think that check valve ever really closed up
perfectly. If I happen to be working outside on a day when I had the
shop shutdown and the air valve turned off I would notice the compressor
would cycle on at least once in a day's time. I just lived with it, and
if I was going to be out of the shop for more than a couple days I would
turn the compressor off entirely.

When I turned off the air and closed the ball valve Tuesday night the
compressor gage read 145. Wednesday morning it had dropped maybe 2 lbs.
It was still above 140. I think that's an order of magnitude better
than it ever was before. It was about the same today. It got me to
thinking.

You might recall I mentioned the plastic valve looked like it was made
of PEEK. PEEK is a pretty hard plastic. In 3000 PSI air guns Acetal is
often used for the valve against a brass or aluminum seat. PEEK is
sometimes used in higher pressure airguns because above around 3500-3800
PSI Acetal may start to "flow." Those valves are typically a tapered
plug that fits into a different angle or even edge radius tapered hole.
The has a minimal contact area for sealing but because its a plug in a
hole pressure causes it to center and seal pretty well. I've got a 3000
PSI Marauder in my back shop I haven't had to refill in nearly a year.
I use it for pests in my garden.

Anyway, I was thinking it might be useful to design my own compressor
check valve using acetal instead of PEEK using proven valave tech like
that in an air gun. PEEK might just be to hard to form a good seal
easily at the low pressure of shop air. Sure a plug in a hole design
might stick a little more than the "flat ring" design the compressor
manufacturer used, but the pressure differential should quickly over
come that. Peak pressure might show a smidgeon high until the vale
opened, but not for very long. As soon as the valve opened up it would
equalize pressure and flow fine until the compressor motor turned off.

Since there is an unloader the compressor would never sit with excessive
back pressure.

Heck at the relatively low pressure of shop air even HDPE might work as
the valve against a smooth metal seat.

I don't mind buying a check valve. I actually already ordered 2. They
are $10 each and some change. I just don't want to install one to have
it be just the same as the old one.


  #2   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 172
Default Check Valve Plastic Valve

On Thu, 19 Apr 2018 12:11:09 -0700
Bob La Londe wrote:

huge snip
As soon as the valve opened up it would
equalize pressure and flow fine until the compressor motor turned off.


Many years ago when I was a tween Dad brought home a small
single stage air compressor that needed a motor. We scrounged up 1/3 hp
and I put it together along with a new hose and fittings. The check
valve had problems so I just removed it. Without the check valve it
wouldn't pump up much and the motor would stall out. Something like
40-50 psi max. Of course it wouldn't hold pressure either, leaking back
through the pump when I pulled the plug... So I cleaned up the check
valve and put it back in. Then it would pump up to over 100 psi before
the motor stalled out. The point being is that the check valve was
cycling back and forth with each stroke of the pump. It didn't just
open and then close when the pump shut off.

I learned a lot about air compressors, quick disconnects... with that
little project. I think Dad planned it that way

--
Leon Fisk
Grand Rapids MI/Zone 5b

  #3   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 1,768
Default Check Valve Plastic Valve

On 4/19/2018 12:46 PM, Leon Fisk wrote:
On Thu, 19 Apr 2018 12:11:09 -0700
Bob La Londe wrote:

huge snip
As soon as the valve opened up it would
equalize pressure and flow fine until the compressor motor turned off.


Many years ago when I was a tween Dad brought home a small
single stage air compressor that needed a motor. We scrounged up 1/3 hp
and I put it together along with a new hose and fittings. The check
valve had problems so I just removed it. Without the check valve it
wouldn't pump up much and the motor would stall out. Something like
40-50 psi max. Of course it wouldn't hold pressure either, leaking back
through the pump when I pulled the plug... So I cleaned up the check
valve and put it back in. Then it would pump up to over 100 psi before
the motor stalled out. The point being is that the check valve was
cycling back and forth with each stroke of the pump. It didn't just
open and then close when the pump shut off.

I learned a lot about air compressors, quick disconnects... with that
little project. I think Dad planned it that way


That is good feedback. I had not considered that an air compressor does
not provide constant pressure above the check valve. I guess when I
need to repair/replace that check valve (soon probably) an experiment
might be in order. Should be pretty easy to add an upstream gage to see
what is happening. Might have to use a digital gage with a data output
of some kind so swings can be logged faster.

  #4   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 172
Default Check Valve Plastic Valve

On Thu, 19 Apr 2018 13:24:39 -0700
Bob La Londe wrote:

snip
I had not considered that an air compressor does
not provide constant pressure above the check valve. I guess when I
need to repair/replace that check valve (soon probably) an experiment
might be in order. Should be pretty easy to add an upstream gage to see
what is happening. Might have to use a digital gage with a data output
of some kind so swings can be logged faster.


It was a loooong time ago... I think I tried putting the pressure gauge
ahead of the check valve too. Rather than on the tank. Needless to say
the needle did a lot of pulsing back and forth. Ooops!

--
Leon Fisk
Grand Rapids MI/Zone 5b

  #5   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 1,768
Default Check Valve Plastic Valve

On 4/19/2018 1:36 PM, Leon Fisk wrote:
On Thu, 19 Apr 2018 13:24:39 -0700
Bob La Londe wrote:

snip
I had not considered that an air compressor does
not provide constant pressure above the check valve. I guess when I
need to repair/replace that check valve (soon probably) an experiment
might be in order. Should be pretty easy to add an upstream gage to see
what is happening. Might have to use a digital gage with a data output
of some kind so swings can be logged faster.


It was a loooong time ago... I think I tried putting the pressure gauge
ahead of the check valve too. Rather than on the tank. Needless to say
the needle did a lot of pulsing back and forth. Ooops!


Oh, no. I wouldn't do that. Just a temporary one to see what is
happening. I used a flexible hard (somewhat) plastic airline in a loop
for my link so I can remove it without kinking it like if I used copper.
I did the same thing on my portable roll around compressor years ago
when I replaced its pump. Its held up fine, but the shutoff pressure is
about 20 PSI lower.






  #6   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 172
Default Check Valve Plastic Valve

On Thu, 19 Apr 2018 13:44:40 -0700
Bob La Londe wrote:

snip
Oh, no. I wouldn't do that. Just a temporary one to see what is
happening.


Nah, not you. Dumb kid did that. I had one of those "DUH!" moments and
found another spot to try

--
Leon Fisk
Grand Rapids MI/Zone 5b

  #7   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 5,888
Default Check Valve Plastic Valve

"Bob La Londe" wrote in message
news
On 4/19/2018 12:46 PM, Leon Fisk wrote:
On Thu, 19 Apr 2018 12:11:09 -0700
Bob La Londe wrote:

huge snip
As soon as the valve opened up it would
equalize pressure and flow fine until the compressor motor turned
off.


Many years ago when I was a tween Dad brought home a small
single stage air compressor that needed a motor. We scrounged up
1/3 hp
and I put it together along with a new hose and fittings. The check
valve had problems so I just removed it. Without the check valve it
wouldn't pump up much and the motor would stall out. Something like
40-50 psi max. Of course it wouldn't hold pressure either, leaking
back
through the pump when I pulled the plug... So I cleaned up the
check
valve and put it back in. Then it would pump up to over 100 psi
before
the motor stalled out. The point being is that the check valve was
cycling back and forth with each stroke of the pump. It didn't just
open and then close when the pump shut off.

I learned a lot about air compressors, quick disconnects... with
that
little project. I think Dad planned it that way


That is good feedback. I had not considered that an air compressor
does not provide constant pressure above the check valve. I guess
when I need to repair/replace that check valve (soon probably) an
experiment might be in order. Should be pretty easy to add an
upstream gage to see what is happening. Might have to use a digital
gage with a data output of some kind so swings can be logged faster.


I made a cam lever that replaces the pull ring on my compressor's
pressure relief valve to unload it enough to start on a small
generator. When the valve is open it pulses like an engine exhaust.
https://www.amazon.com/Forney-75552-.../dp/B003X5XJPM
-jsw


  #8   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 9,025
Default Check Valve Plastic Valve

On Thu, 19 Apr 2018 15:46:39 -0400, Leon Fisk
wrote:

On Thu, 19 Apr 2018 12:11:09 -0700
Bob La Londe wrote:

huge snip
As soon as the valve opened up it would
equalize pressure and flow fine until the compressor motor turned off.


Many years ago when I was a tween Dad brought home a small
single stage air compressor that needed a motor. We scrounged up 1/3 hp
and I put it together along with a new hose and fittings. The check
valve had problems so I just removed it. Without the check valve it
wouldn't pump up much and the motor would stall out. Something like
40-50 psi max. Of course it wouldn't hold pressure either, leaking back
through the pump when I pulled the plug... So I cleaned up the check
valve and put it back in. Then it would pump up to over 100 psi before
the motor stalled out. The point being is that the check valve was
cycling back and forth with each stroke of the pump. It didn't just
open and then close when the pump shut off.

I learned a lot about air compressors, quick disconnects... with that
little project. I think Dad planned it that way


Dads are great that way, aren't they? I learned woodworking and
automotive repair from mine, with some physics on the side. Cut my
eye teeth tuning up his metal spoke rims on the Austin Healey 100-4 he
ran in gymkhanas and autocrosses.

If Bob's new valve leaks, I hope he calls the mfgr and raises hell.

--
When a quiet man is moved to passion, it seems the very earth will shake.
-- Stephanie Barron
(Something for the Powers That Be to remember, eh?)
Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
GÜRTAN PLASTIC - PLASTIC CRATES,PALLETS and ALL TYPE OF PLASTIC PRODUCTS [email protected] Home Repair 0 August 1st 07 08:50 AM
GÜRTAN PLASTIC - PLASTIC CRATES,PALLETS and ALL TYPE OF PLASTIC PRODUCTS [email protected] Home Repair 1 July 11th 07 02:18 PM
GÜRTAN PLASTIC - PLASTIC CRATES,PALLETS and ALL TYPE OF PLASTIC PRODUCTS [email protected] Home Ownership 0 July 11th 07 12:47 PM
Valve,Butterfly valve,Globe valve,Check valve,Ball valve,Plug valve,Marine valve,Gate valve,Flow control valve [email protected] UK diy 1 April 17th 06 10:29 AM
Valve,butterfly valve,ball valve,check valve,globe valve [email protected] Home Repair 0 April 14th 06 10:23 AM


All times are GMT +1. The time now is 01:59 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"