Jump to content
  •           ai.php.gif

ledfoot

A High Volume, Low Pressure Oxygen System for Propane Glassworking Torches

Recommended Posts

This is my plan for a high volume, low pressure oxygen system for operating propane glassworking torches.

[Disclaimer: I know next to nothing about glassworking, and I am not an engineer.]

My only original bit on this system is a combo vacuum/pressure gage at the outputs of the oxygen generators. The generators (concentrators) contain sieve beds (for nitrogen removal) that can be damaged by a vacuum condition.

The concentrators are rebuilt home medical units.

I haven't built it yet but this system will run a GTT brand Phantom torch at full blast.

 

gallery_6205_6166_209153.jpg

 

 

 

The compressor is an oil-free design. Gast 86R123 Flow vs Pressure graph:

 

gallery_6205_6166_55451.jpg

 

 

 

The system will be assembled in a rack of 2x4 foot wire shelves.

gallery_6205_6166_91808.jpg

 

 

 

Detail of the Condor brand four-port pressure switch.

gallery_6205_6166_2902.jpg

 

 

Right now, I'm waiting for some parts and I need to clear my install space.

Share this post


Link to post
Share on other sites

I've decided to move to another location before I build a glass studio.

This is a commercially available HVLP system:

 

If you want to know more about the concentrators:

 

Share this post


Link to post
Share on other sites

In case anyone is wondering why I'm posting this here, it is because the president of the High Volume Oxygen company has threatened to sue people (including serving papers, I guess).  The (BS) HVO patents are here: https://www.highvolumeoxygen.com/patents/

Background: http://www.talkglass.com/forum/showthread.php?64885-oxygen-frog-verses-high-volume-oxygen-pro-and-con-im-leaning-toward-frog-thanks-craig

I've made two changes to my design after watching the Torch Talk videos.  I was planning to let the concentrators run continuously.  This would be wasteful but manageable, the wall exhaust fan would prevent excess pooling of oxygen in the work area, I think.  The solenoid bleed valve on a timer is a more elegant solution. (What is needed is for the sieves to purge for a minute or two before the oxygen reserve tank is filled.)

I was planning to purge the holding tanks at the start of each shift but would need a flow restrictor for the initial part of the fill.  My new plan will slow the compressor down until the pressure is about 45 PSI.

The speed control will be accomplished with an autotransformer from Parts Express (with a fuse added to the secondary).  A PWM fan control would likely work but the transformer should be smoother.  I would guess Oxygen Frog uses variable PWM.  My design is a two-speed arrangement after the initial adjustment.

Plan2.thumb.jpg.608076c35e51b768612295ae45346f09.jpg

Ladder.jpg.926a838916a423c685e70dd1c576b727.jpg

Timing.jpg.5189ef79a8e3472633adcb48e997d2f4.jpg

 

Edit: I love zoro.com (a division of Grainger).  They run this discount several times a year (good through the 24th):

zoro.jpg.2a6c012fabf2dc89cffa2faa7d611733.jpg

I've seen this compressor used most often by DIY people: https://www.zoro.com/gast-piston-air-compressor-16hp-115v-1ph-1hab-44-m100x/i/G1222715/ You will find the flow/pressure curve at gast.com.

 

Edit2: A good explanation of autotransformer motor starting: Theory Of Operation - Autotransformer Starter.pdf  (but not really the same thing as the use in my design.)  I'm quite sure the Gast 86R uses a PSC (permanent split capacitor) type motor.

And I can de-rate the primary fuse in the Parts Express variac to protect the secondary circuit.

Edit3: The timer contacts need to be rated to handle the inductive load of the solenoid.  If not, the timer should operate a power relay coil instead.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×