Tank Equalizer for $2.50

[Couv]

Hello All,

Over the last couple of days I have been asked by PM about making an inexpensive tank equalization hose. Here is an updated version on how to accomplish that. To cheaply equalize two tanks or just to add a bit of pressure to one from the another, you only need 2 regulators, a submersible pressure gage hose, and an inexpensive fitting that can be obtained from a hydraulic hose shop or from Granger.

Here are two methods:
Method A
1. Install one regulator onto the donating tank valve and one regulator onto the receiving tank valve.
2. Remove the submersible pressure gage (SPG) and spool from the hose of the donating tank's regulator.
3. Remove a high pressure port plug or the submersible pressure gage hose of the receiving tank's regulator.
4. Install the hose adapter into the HP port: Male JIC Thread 7/16-20 In, SAE Straight Thread 7/16-20 In
Hose Adapter, SAE to JIC, Straight - Hydraulic Hose Adapters and Plugs - Hydraulic Hoses - Pneumatics & Hydraulics : Grainger Industrial Supply

5. Install the donating hose onto the receiving adapter.
6. Make sure all connections are secure and slowly open the tank valves-voila, you are equalizing.

Method B is the same as Method A except you remove both SPGs and spools from the ends of the donating and receiving regulators and install a different type of fitting to join the two HP hoses together.
Male Straight Union, 1/4 In Tube Sz, SS - Stainless Steel Tube Fittings - Fittings - Plumbing : Grainger Industrial Supply

Be very careful: You are dealing with high pressure gas. DO NOT INSTALL THE HIGH PRESSURE HOSE INTO A LOW PRESSURE FITTING-DO NOT USE A LOW PRESSURE HOSE.

Couv

 

[herman]

Someone ask about something similar in another post and while thinking it over I came to the conclusion you really need either a second stage or relief valves on both ends for a couple of reasons (I am assuming you are dedicating a couple of old first stages for this). First off, how are you going to bleed off the pressure when you try to remove the regs? Secondly, if the regs are OK everything would be fine but what if the IP on one or both regs goes high? You could end up with HP side pressure on the LP side. This is surely going to blow out a diaphragm or piston Orings at a minimum if not something more dramatic. For safety’s sake, IMO some form of pressure relief is needed on both ends as well as a means of depressurizing the regs when the transfer is done.

 

[tbone1004]

OPV's can be had from Piranha for like $5 each, which would be a good solution, then just buy an air gun adapter and a LP hose to purge

 

[kramynot2000]

Thanks for the info. I've been looking for a cheap way to top off some of my small bottles and I happen to have spare first stages in the parts bin so I'll give it a try.

 

[ianr33]

How clean is hydraulic hose? Any chance of dumping a load of hydrocarbons into the tank that was at lower pressure?

Also equalizing pressure through a HP hose is going to take a while. 10-20 minutes??

 

[rcs9250]

I have used COUV's method B many times. On a boat though the crew might give you some strange looks or even ask you not to do it on their boat.

 

[Couv]

How clean is hydraulic hose? Any chance of dumping a load of hydrocarbons into the tank that was at lower pressure?

Also equalizing pressure through a HP hose is going to take a while. 10-20 minutes??

Hi Ian,

This is just a small metal fitting (that you O2 clean if you wish using the typical methods), not an entire hydraulic hose. You use your SPG's high pressure hose.

I would guesstimate you could equalize an empty 80 and a full 80 in about 15 minutes....probably faster.

c

 

[Couv]

snip....you really need either a second stage or relief valves on both ends ....

New Orleans, 1978:
Couv, "Dr. Hill, why did you give me an F on my very first English 101 assignment?"

Dr. Hill, "Because you did not consider your audience."

Couv, "I assumed my audience was experienced with the materials discussed in the paper."

Dr. Hill, "Take the ass out of assume and it leaves, U and ME. Make that an F minus."

I guess I'll never learn.

OK, OK, Dr. Hill, Herman, and the rest of you. I assumed too much in post #1 of this thread. Give me an F, but forgive me just a little as this is the DIY section. The intent of this post was to address the most common reasons one would want to transfer just a few cubic feet of air from one bottle to another. Mainly I had in mind the typical cases where you need to avoid the VIP Nazis. One example would be if you travel with a pony bottle on an airline and have to remove the valve; another case would be if you want to remove the valve from a tank to have a peek inside or perhaps just to install a different valve. Some people want to top up there pony every now and then without having to pay for an entire fill. I'm sure there are as many examples as there are tank monkeys with reasons not to fill an empty tank.

So I'll fess up. I assumed most of you wanting to use this technique would use two fully functioning regulators-including a second stage attached to each first stage-just as you would have on a dive trip. However, as Herman points out, ANYTIME you install a regulator on a tank there MUST be some form of protection should the intermediate pressure decide to run away. Usually that protection is provided by the second stage and would be in this case. Likewise, the second stage provides a way to purge the pressure from the system after the transfer is complete.

Again, this method is for the occasional need to move a small bit of gas from one bottle to another. The $2.50 fitting is just a very small addition to your Save-a-Dive kit; it's not intended to replace a cascade system. ...If you need a fill whip-get one.

Cheers,

Couv with an F-

 

[ianr33]

Hi Ian,

This is just a small metal fitting (that you O2 clean if you wish using the typical methods), not an entire hydraulic hose. You use your SPG's high pressure hose.

I would guesstimate you could equalize an empty 80 and a full 80 in about 15 minutes....probably faster.

c

Guess I should learn to read a little more closely

Actually I'm liking the idea. I dive sidemount most of the time . Having 2 tanks with different pressures at the end of a dive is a pain if you are partial pressure blending.

This adapter is much cheaper and lighter than a regular transfill whip.

I would probably get a dedicated HP hose for this rather than messing with the delicate spool O rings . (And my HP hoses are only 6 inches long)

Thanks for the suggestion.

 

[txapacheguy]

Thanks for the idea and the links to the products on Grainger's website. I knew something like that could probably be done, but just never did the homework to make it happen. I went ahead and ordered both adapters(hopefully Grainger won't rape me for shipping, as they do not display the shipping charge when you check out).