Hookah ,diy

[Cormorant]

A bit of thread drift here, but I'm curious. . . . Fstbottoms, does the plunger ever get TOO stuck onto the hull? Is it hard to move along? Did you build in a pressure-release mechanism?

[fstbttms]

Originally Posted by Cormorant

A bit of thread drift here, but I'm curious. . . . Fstbottoms, does the plunger ever get TOO stuck onto the hull? Is it hard to move along? Did you build in a pressure-release mechanism?

No, no and no.

[CGirvan]

It seems the Thomas 1020 or 1207 are the recommended compressors for 120v is there a similar recommendation for 12v compressors.

[Laughing Buddha]

Originally Posted by CGirvan

It seems the Thomas 1020 or 1207 are the recommended compressors for 120v is there a similar recommendation for 12v compressors.

PLEASE - DON'T TAKE THIS AS A RECOMMENDATION > It is my analysis, I built for my needs, just sharing.


I've been reading all available on DIY Hookah rigs and have been sleuthing for a suitable 12v reasonable weight solution.

BACKGROUND:

I am a PADI/NAUI Advanced Diver, but have given my tanks away as they were way out of cert. I had been using them as a deck bound SNUBA, with a 50 foot Keene Hose, and the octopus from my old rig for prop inspection and cleaning and hull scrubbing. I don't have 100s of hours of bottom time, but I have Snuba'ed the bottom of the boat in the Chesapeake, Baja Mexico, Fiji, and Vanuatu. So I have some experience, and a hose. I plan on upgrading the Regulator. I need to source the compressor/pump(s). Naturally the pump must be an oil less air compressor, well documented in threads here and elsewhere. What would be nice is to know if the rig provided Grade E air. None of the companies list that information (legal departments I reckon). The Airline has their pump purpose built for them, and get them certified a Grade E. But too much gear to bag and put in luggage.


I started the fool's errand of trying to find a Thomas 1020, but it and the 1207 are both AC systems and I am seeking a 12v DC setup. The Thomas built(?) pump for the Airline DC Hookah rig seems a natural, but, unable to find a source for the pump only, and more about its output after the following analysis.

Returning to post #70...

Originally Posted by Celestialsailor

Does anyone know what the minimum CFM is required for a DIY Hookha set up for a 2 meter depth?

This was the first thing I needed to resolve - how much capacity required for a pump. Various sites suggest 2CFM at 90 psi ought to be right for my requirements. [I believe this is from the forum somewhere; [...Yandina says minimum 1hp; min 2.5cfm @ 100 psi. There's a lot of oiless (sic) compressors that don't come close to those specs.] And, another very accurate one; [... It depends on how deep you are and what you're doing.]



I did find a set of formulas to determine the CFM required at depth. Not pressure - but CFM.
Start with determining the effort used under water, the RMV or Respiratory Minute Volume.

There was a handy Table (Source lost)
These are commonly accepted RMV's.

To convert to CFM, multiply by ATA (1 at surface) and divide by 28.31.
CFM = (RMV * ATA)/28.31

But we'd want the ATA at depth, so you adjust for diving below the surface in salt water.

ATA are (depth-in-ft +33)/33 >> So, for an 8 foot depth, (8+33)/33, the ATA @8ft 1.25

For Light - Moderate work RMV = 20, so;
CFM = (20*1.25)/28.31 0.88

Thus for non-extreme work near the surface 2 CFM should be more than adequate.

Calculating the pressure requirements are a bit more complex, but if you can get 2 cfm at 90psi, it should suffice.


MY SELECTION PROCESS:

Knowing that about 2 CFM would meet my needs, I had to put a few more factors in the selection. I'll be hand carrying the compressor with me to South East Asia. So weight is a big deal, as is price.

I found a number of compressors and data over at air compressors direct (satisfied with them previously).

My data looks like this:



The results like this:




NOTES: to make the CFM readable on the chart it is presented as CFM*100. Also, note the California Air Tools Unit is quite good - but I'd never get it into my baggage! The Puma DE07 also very good - but with the VIAIR 440c-Dual, you get 2 pumps and the heat resistant hose in the bargain, and only costs about $20 more! Note the Airline gets only 2.18 CFM @ 50 PSI, so not likely to get 2 near 90, so I did not put it in the mix.

The amps required for many of the 12v systems run from 26 - 50 depending on size or number of motors on the pump setup. The Viair Duals run 44 Amps - not great - but do-able. The Airline site says 26 amps for its 1/4 hp motor.

I hope this proves useful to someone - and if there are any errors please let me know and I'll fix 'em.

Cheers - Jim

[toddster8]

An interesting data collection. I might have been more concerned with power draw than cost among these units.

Another crucial bit here is whether or not the unit is rated for continuous duty. I don't think those little 12V pumps are. By using a reserve tank, a cooling period is introduced into the duty cycle. The larger the tank, the more time the compressor is off and cooling.

One more comment: I've had a look at the Puma 12V compressor and it's obvious right out of the box that there is considerable residue of machining oils in the package. Certainly you'd use filters, but I would disassemble and clean the whole thing before attempting to breathe from it. Probably this is the difference between it and the "certified" unit sold by that hookah dealer. Likely the same is true of other such units. (So far I'm just using it for inflating water toys. But hey, maybe an air horn or some pneumatic tools down the road.)

[Laughing Buddha]

Excellent comments - Thank you.

Great observation on the oil and rebuild/check out - will do.

TRUE -- Amp/Power draw lives long after the purchase. But, use is infrequent, battery banks large (1100 Ah), and many competing projects for the cash in the wallet...and carry in luggage a big consideration as I mentioned.

I chose to look for as close as I could find for a continuous duty pump. Not many. All in the analysis are 100% Duty Cycle. And you know that is NOT Continuous. It seems to be the accepted rate of; 1 Hour ON -- 1 Hour OFF.

Reserve Tank is a good idea for a number of reasons.

Cheers - Jim

[fstbttms]

Originally Posted by Laughing Buddha

The Airline has their pump purpose built for them...

Not so. The Air Line 12-volt compressor is simply a Thomas 270025. There are no purpose-built air compressors for any hookah rigs sold at the consumer level. It is possible that Thomas adds a few bells and whistles at Air Line's request (as they do for other Air Line 110-volt units), but the base compressor is one that anybody can buy and is available from many sources.



https://www.grainger.com/product/2KF...170731220047:s

[Laughing Buddha]

Fast Bottoms! Great to have you here - seen and read many of your posts around the interweb.

Thanks for that! Their advert led to that conclusion - thanks for the correction! I must have misread/scanned too quickly.

But NOW - a big question (or 2):

1. Is that pump really bring more value to a "shallow dive system" -- given the price of $1400?
2. Any comments on the analysis of other available 12v pumps?

I've found lower prices around the web - but have been focused as I wrote earlier.

As you have time -- your comments please.

Cheers - Jim

[fstbttms]

Originally Posted by Laughing Buddha

Fast Bottoms! Great to have you here - seen and read many of your posts around the interweb.

What are you talking about? I've been posting in this thread since last year.

Originally Posted by Laughing Buddha

Is that pump really bring more value to a "shallow dive system" -- given the price of $1400?

You get what you pay for. Buy a cheap compressor at your own peril. I would never advise that you do so. But I'm biased.

Originally Posted by Laughing Buddha

Any comments on the analysis of other available 12v pumps?

I have never used a 12-volt system, so I can't comment. All I know is that Thomas compressors are the hull cleaning industry standard. I would never use anything but.

[Laughing Buddha]

Originally Posted by fstbttms

What are you talking about? I've been posting in this thread since last year.

No - I know that - what I meant was; I'm glad to have your opinion offered. Thank you.

From your post, I gather you'd put more value/promise/faith/credibility on the $1400 Thomas as "superior" to other alternatives. But then, Ford drivers prefer Fords over Chevys. Familiarity with this PARTICULAR type of equipment - I have none.

I'm not going to question their (Thomas's) credibility/engineering/etc. - But - what are the rates one should look for in a pump/compressor for performance? Does the $1400 pump provide the 2 CFM at 90PSI -- or is that a bogus metric to evaluate these compressors? What CFM and pressure is "required" for shallow diving? I think I answered the CFM in the earlier post. I just want to know.

Sir - I've seen your post here and on other dive sites before - and have a sense that as an expert - you can help me (maybe others) through this decision making process.

So my question remains:

CFM - what is the minimum value one should seek? And at what PSI?
EXAMPLE - "Dredge Divers" use 35-50 psi as a rating and 2 CFm - OK they are very shallow. I'm trying to reach an intermediate solution - surface - to maybe 10 feet down.
My analysis seems to get to 2.0 CFM @ 90 PSI as a good value. But I am Inexperienced in this type of diving.

Somebody could buy one of the Chinese Hookah rigs you see on eBay, and miss the mark and get hurt. Through their own (untrained) fault - or equipment. Finding and offering a "solution" could provide a vector for potential purchasers.

So here, I want to focus on equipment. I accept the risks (hell, I also race cars, and used to fly fighters) but am clever enough to want to choose equipment that meets the requirements, AND, THAT THE EQUIPMENT MEETS THE REQUIREMENT.

So far, the best Requirements I see are:

Oil less Compressor -- CHECK
About 2.0 CFM @ 90 PSI - Is this fact or Word of Mouth? ??
Around 100- 135 psi max (more ok) - Shallow systems seem much less ??
Continuous Duty Highly Desired - 100% acceptable ??
Highly desired 12v (probably 50 amps for 3/4 - 1 HP motor)
Amps is amps AC -on inverter or direct from DC with losses...

And if possible a rating of Grade E from manufacturer - or long term use by other hookha divers - for example - you've used the Thomas 1027 and it is NOT rated Grade E- is it? And, you have 1000s of hours on it? No Ill effects or medical problems?

Looking forward to you helping me (maybe others) in making this choice.

Cheers - Jim

[toddster8]

Amps ain't Amps. Amps is Watts/Volts. You want to compare Watts. Watts is Watts.

[fstbttms]

Originally Posted by Laughing Buddha

No - I know that - what I meant was; I'm glad to have your opinion offered. Thank you.

From your post, I gather you'd put more value/promise/faith/credibility on the $1400 Thomas as "superior" to other alternatives. But then, Ford drivers prefer Fords over Chevys. Familiarity with this PARTICULAR type of equipment - I have none.

I'm not going to question their (Thomas's) credibility/engineering/etc. - But - what are the rates one should look for in a pump/compressor for performance? Does the $1400 pump provide the 2 CFM at 90PSI -- or is that a bogus metric to evaluate these compressors? What CFM and pressure is "required" for shallow diving? I think I answered the CFM in the earlier post. I just want to know.

Sir - I've seen your post here and on other dive sites before - and have a sense that as an expert - you can help me (maybe others) through this decision making process.

So my question remains:

CFM - what is the minimum value one should seek? And at what PSI?
EXAMPLE - "Dredge Divers" use 35-50 psi as a rating and 2 CFm - OK they are very shallow. I'm trying to reach an intermediate solution - surface - to maybe 10 feet down.
My analysis seems to get to 2.0 CFM @ 90 PSI as a good value. But I am Inexperienced in this type of diving.

Somebody could buy one of the Chinese Hookah rigs you see on eBay, and miss the mark and get hurt. Through their own (untrained) fault - or equipment. Finding and offering a "solution" could provide a vector for potential purchasers.

So here, I want to focus on equipment. I accept the risks (hell, I also race cars, and used to fly fighters) but am clever enough to want to choose equipment that meets the requirements, AND, THAT THE EQUIPMENT MEETS THE REQUIREMENT.

So far, the best Requirements I see are:

Oil less Compressor -- CHECK
About 2.0 CFM @ 90 PSI - Is this fact or Word of Mouth? ??
Around 100- 135 psi max (more ok) - Shallow systems seem much less ??
Continuous Duty Highly Desired - 100% acceptable ??
Highly desired 12v (probably 50 amps for 3/4 - 1 HP motor)
Amps is amps AC -on inverter or direct from DC with losses...

And if possible a rating of Grade E from manufacturer - or long term use by other hookha divers - for example - you've used the Thomas 1027 and it is NOT rated Grade E- is it? And, you have 1000s of hours on it? No Ill effects or medical problems?

Looking forward to you helping me (maybe others) in making this choice.

Cheers - Jim

You're putting WAAAAAY more thought and effort into this than you need to, IMHO. I don't know what specs are necessary to do whatever it is you plan to do, but I guarantee the Thomas 1207 or 270025 will meet or exceed them. Use the specs from either of those units (if you do not plan to buy either) to base your purchase of another compressor. Any oil-less compressor will be safe to breathe from. But know that cheap (read: Made in China) machines will not have the durabilty or overall quality of of an American made unit. Again, you get what you pay for.

[Laughing Buddha]

Originally Posted by fstbttms

...I don't know what specs are necessary to do whatever it is you plan to do, but I guarantee the Thomas 1207 or 270025 will meet or exceed them. Use the specs from either of those units (if you do not plan to buy either) to base your purchase of another compressor. Any oil-less compressor will be safe to breathe from. But know that cheap (read: Made in China) machines will not have the durabilty or overall quality of of an American made unit. Again, you get what you pay for.

Excellent advice from the voice of experience. Thank you, thank you.

Cheers - Jim

[denverd0n]

I need to do more research into this, but...

If you apply 14.7 psi of pressure to air in a tube that runs from the surface down into the water, you will push the air down approximately 33 feet. Double the pressure, double the distance down that you push the air column. So, just getting the air down to that depth does not take a lot of pressure.

The question then becomes, how much additional pressure is required -- beyond what gets the air down to that depth -- in order for a human to breathe the air through a regulator of some sort? I cannot imagine that the required delta is all that much.

Hence -- again, with minimal actual research, but just reasoning this through -- I do not see where 90 psi at the surface would be required for relatively shallow diving. It seems logical to me that 45-50 psi would be more than enough for dives less than 30 feet. In fact, it may well be that 50 psi is completely adequate for dives down to 50 feet.

As mentioned, I do intend to look into this more.

Of course, as fstbttms said, we may be WAAAAAY over-thinking this. :-)

[denverd0n]

Okay, even if we're over-thinking this, it strikes me as an interesting mental exercise, so...

At sea level the air we are breathing is 14.7 psi. Therefore, if you add 14.7 to the pressure required to push the air column down to your depth (and assuming you have a regulator that will function at that pressure) you should be able to breathe just fine.

Of course, I lived in Denver for a long time, and climbed many of the 14-ers in Colorado. At, for example, 14,300 ft. of altitude the air pressure is only about 9 psi. Of course, I was a bit winded from the climb up the mountain, but once on top and rested, I had no problem breathing air at 9 psi. So you don't need every bit of 14.7 psi to breathe.

So, logically speaking, if it takes 14.7 psi to push air down 33 ft., and you want an additional 14.7 psi to make it easily breathable, then 30 psi should more than enough pressure for breathing at 33 ft. It is then just a matter of providing an adequate volume of air at that pressure, and a regulator that will function.

Make sense?