We just bought an old dive compressor, scrap or usable?

[Thomas Thorsell]

We just bought an old Bristol dive compressor from a local professional diver. We are trying to assess if it was a good or a bad buy and what we need to do to it to be able to use it filling dive bottles.
We are also very interested in any information regarding model number, capabilities etc.

When we were to test it with the seller it turns out that it didn't build any pressure at the fill whip but it did build some pressure in the filter, could it be the pressure maintaining valve which is placed on the bottom of the filter tower that have clogged? Any other suggestions?

BTW the filter cartridge is stamped 03/1975, usable?
Also if someone knows where we can buy the filter discs for the filtration tower it would be appreciated.

 

[tbone1004]

you may just not have run it long enough for the pressure in the filters to exceed the PMV setpoint. Depends on how long you ran it, how big the filter is, etc etc. I.e. it looks like a 5 ish CFM compressor. The filter we can say is probably around .1cf based on the size, and the PMV is probably set around ~150bar which means it holds ~15cf before the PMV opens and will take ~3 minutes of the compressor running before the whip gets gas.

Now it's obviously possible the final stage needs to be rebuild, a valve isn't working properly, etc etc.

With a 1975 date on the cartridge, it definitely needs at least a proper cleaning but it is probably worth the peace of mind to buy a new filtration system for it

 

[grf88]

Contact
Shelden Sporting Goods Inc. - High Pressure Air Compressors
He is frogman62 on this board and may be able to help you with his comprehensive knowledge.

 

[iain/hsm]

We just bought an old Bristol dive compressor from a local professional diver. We are trying to assess if it was a good or a bad buy and what we need to do to it to be able to use it filling dive bottles.
We are also very interested in any information regarding model number, capabilities etc.
.

I’m just checking back to see if I’m still banned from this forum.
From your photo its an old 3 stage Bristol Pneumatics Bristol UK
The air intake filter on the top is a Vokes Fiters UK and looks a little too small
The brass relief valve at top right is a Seetru Bristol UK
The relief valve at the front looks like a Yankee Kunkle no idea why thats on
The BPR is at the back of the filter just in the photo its a MDE UK
And the filter tower is a MDE UK Series 50 (replace every 15 years)
The red knob bottom centre of photo is the filter bleed valve
Underneath the filter is a small stainless burst disc make sure its not burst already
and the red knob is closed fully.
Also the Red separator drain valve far right in your picture make sure thats close and not leaking.
Its off an old Dunlop compressor
The brass fittings on the copper tubing are Enots fittings UK
The motor hard to identify but possibly an old Brook Crompton
The steel compression olive fittings are from Brownall UK
You need to check the drive belt, that its not cracked and about to fail also those HP rubber hoses
after all this time. Also hope you checked the oil level and condition before you started the thing.
Taking a peek inside the air filter and the first stage pipe hole for rust would also have been helpful
Now you have paid for it drain the filter tower of air and unscrew the filter tower look inside
for oil carryover and check the oil before you start it again.
Judging by the frames dark “grey” hammer finish colour (Trimite Hammerite Paints UK) its an original base plate frame and belt guard cover but from a much later model.
With that much older MDE filter and a similar older Bristol block modified from an original CNG gas application back to being a air compressor. And the more recent “beer tap” dispensers. It’s a good example of what is known as a Frankenstein Build. Manuals and parts list are still available for free.
I guess someone else changed the oil from its early days or it will stink. I don’t suppose he told you what oil it was running on.

 

[divad]

Why were you banned?

 

[Kirk king]

i have a bigger version of this its a bristol 18 cfm compressor its bullet proof!!

 

[windyairman]

its a bm4s7k about 5cfm
i have loads of spares and manuals for this pump
its a 4 stage not 3 stage as you have been told.

 

[Thomas Thorsell]

Cool, thank you for all the info. The gent we bought it from was the one running it for us. The oil looked good and didn't smell bad. He did run it a short while without the filter and there was some oil dripplets blowing through. Is this a concern or will the filter tanke care of it?

 

[Thomas Thorsell]

its a bm4s7k about 5cfm
i have loads of spares and manuals for this pump
its a 4 stage not 3 stage as you have been told.

Could we gat a manual from you?

 

[JamesBon92007]

Cool, thank you for all the info. The gent we bought it from was the one running it for us. The oil looked good and didn't smell bad. He did run it a short while without the filter and there was some oil dripplets blowing through. Is this a concern or will the filter tanke care of it?

I also want to know: what oil did he say to use? If you have "oil droplets blowing through" I'm wondering if it's the correct type of oil.

It seems odd that he didn't know that the back-pressure valve doesn't open until it reaches it's set point.