Fording Project

[rmgill]

Rusty, could you give a rundown of the parts and typical cost for them if possible?

The Gauge, Regulator and solenoid are key.

I've been contemplating this myself. I'm about to install a remote BFS reservoir and have the parts on order. A fording pressurization system is the next tweak to do to my truck.

 

[rustystud]

Rusty, could you give a rundown of the parts and typical cost for them if possible?

The Gauge, Regulator and solenoid are key.

I've been contemplating this myself. I'm about to install a remote BFS reservoir and have the parts on order. A fording pressurization system is the next tweak to do to my truck.

Well the gauge I can't help with as I already had it. I would "assume" they would sell for $50.00 or less. The regulator I got on eBay. Remember it is a "low pressure" regulator and you will need the flow regulator also. The regulator cost me $30.00 and the "flow control" cost $20.00 . The solenoid is another problem. The one I just bought will not work . It needs a higher amount of air pressure to be able to close. It actually uses the incoming pressure to help close the valve. So I must find a different design solenoid. Oh well there is always something going wrong !
I'll let everyone know what I find.
I forgot to mention why I have to use a "flow control" in the system. At low pressures the regulator will "pulse" so the flow control smooth's out those pulses.

 

[tommys2patrick]

While operating, does any lube work its way out of the small areas that "leak" pressurized air? Or is it so minimal (if any) as to be inconsequential? Great thread by the way. I like your story about pack ratting. I learned the value of old coffee cans from my dad. Almost never throw away anything now. haha

 

[rmgill]

Well the gauge I can't help with as I already had it. I would "assume" they would sell for $50.00 or less. The regulator I got on eBay. Remember it is a "low pressure" regulator and you will need the flow regulator also. The regulator cost me $30.00 and the "flow control" cost $20.00 . The solenoid is another problem. The one I just bought will not work . It needs a higher amount of air pressure to be able to close. It actually uses the incoming pressure to help close the valve. So I must find a different design solenoid. Oh well there is always something going wrong !
I'll let everyone know what I find.
I forgot to mention why I have to use a "flow control" in the system. At low pressures the regulator will "pulse" so the flow control smooth's out those pulses.

Does your flow work like this?

HP (~100 PSI) Air -> LP regulator -> 3 Way solenoid Valve -> Gauge/diffs/gearboxes

What happens when you suffer an electrical failure while running through the water?

Seems like a manual control 3 way valve would make things a touch simpler ? Would an Air Shift Switch work? They vent when off...

 

[Another Ahab]

So, the 2-3 psi is all that is required to keep water out because I'm guessing the water depth is so minor (< 4' +/-), right?

2-3 psi sounds so minimal, but I'm guessing it's enough to "push" out any intruding water.

Because i'm guessing fording anything deeper would require proportionally more air pressure against the increased water pressure. Anyone know the science there?

 

[rmgill]

Ahab, pretty much the idea. For every 33 feet, the pressure doubles. At sea level the absolute pressure is 1 atmosphere, that's the weight of all the air to space at that point (aka 14.69 pounds of air per square inch). At 33 feet it's 2 atmpospheres or 30 psi.

Note here:
http://www.calctool.org/CALC/other/games/depth_press

at 0 Feet, the Pressure is 14.69 PSI aka 1 Atmosphere.
A regulator is going to regulate pressure based on the pressure it's at PLUS what ever else you regulate the pressure from it's a relative measurement system. So it's relative to the air outside. (see how a regulator works to see why https://www.youtube.com/watch?v=Kf3xc1BGYGo).

At 1 foot depth under water the pressure is going to be 15.14. So about .45 psi relative to above water.
at 2 feet its 15.58 PSI - .89 psi relative
at 3 feet its 16.02 PSI - 1.33 psi relative
at 4 feet its 16.47 PSI - 1.78 psi relative
at 5 feet its 16.91 PSI - 2.22 psi relative

 

[Another Ahab]

Thanks for the explanation rmgill:

- Physics is very cool

The part about it in school that I didn't like was the test-and-quiz stuff and the d*** grades to worry about.

 

[Styk33]

This is an interesting idea. I like it. An easier way to calculate it would be .4335psig=1 foot of water.

 

[rustystud]

Ahab, pretty much the idea. For every 33 feet, the pressure doubles. At sea level the absolute pressure is 1 atmosphere, that's the weight of all the air to space at that point (aka 14.69 pounds of air per square inch). At 33 feet it's 2 atmpospheres or 30 psi.

Note here:
http://www.calctool.org/CALC/other/games/depth_press

at 0 Feet, the Pressure is 14.69 PSI aka 1 Atmosphere.
A regulator is going to regulate pressure based on the pressure it's at PLUS what ever else you regulate the pressure from it's a relative measurement system. So it's relative to the air outside. (see how a regulator works to see why https://www.youtube.com/watch?v=Kf3xc1BGYGo).

At 1 foot depth under water the pressure is going to be 15.14. So about .45 psi relative to above water.
at 2 feet its 15.58 PSI - .89 psi relative
at 3 feet its 16.02 PSI - 1.33 psi relative
at 4 feet its 16.47 PSI - 1.78 psi relative
at 5 feet its 16.91 PSI - 2.22 psi relative

I'm glad my math worked out. It's nice to know I didn't forget everything from my diving days !

 

[rustystud]

So, the 2-3 psi is all that is required to keep water out because I'm guessing the water depth is so minor (< 4' +/-), right?

2-3 psi sounds so minimal, but I'm guessing it's enough to "push" out any intruding water.

Because i'm guessing fording anything deeper would require proportionally more air pressure against the increased water pressure. Anyone know the science there?

It is actually keeping the seals from collapsing allowing in water.

 

[rustystud]

Does your flow work like this?

HP (~100 PSI) Air -> LP regulator -> 3 Way solenoid Valve -> Gauge/diffs/gearboxes

What happens when you suffer an electrical failure while running through the water?

Seems like a manual control 3 way valve would make things a touch simpler ? Would an Air Shift Switch work? They vent when off...

The flow chart looks like this. The 120 PSI air comes into the low pressure regulator and out through the flow regulator to the gauge and the air manifold. From the air manifold all the hoses go out to each gear unit. The solenoid valve just closes the "vent" on the air manifold.
I did think about a manual valve to the air-manifold but I couldn't find one cheap enough. Plus it is just cool to throw a switch and have it done ! Of course if I did loose power to that solenoid I would flood out all my gear boxes immediately !

 

[rustystud]

While operating, does any lube work its way out of the small areas that "leak" pressurized air? Or is it so minimal (if any) as to be inconsequential? Great thread by the way. I like your story about pack ratting. I learned the value of old coffee cans from my dad. Almost never throw away anything now. haha

You really shouldn't loose any oil unless you already had a leak to begin with. Even then you would mostly just loose air.

 

[rustystud]

Well I found another solenoid. It might take awhile to get here since it's coming from China ! At least it's only $17.00 . Hope this one works.

 

[tim292stro]

1Bar(14.7psi)/10M(33 feet approximately) if I recall my dive math correctly - of course I let my cert lapse more than ten years ago. I do recall that there is a difference with freshwater and saltwater density that affects the rate of pressure/depth change.

Color me curious as to how you are splitting the regulator output to the various target cases - how do you maintain accurate pressure in each case?

 

[rustystud]

to

1Bar(14.7psi)/10M(33 feet approximately) if I recall my dive math correctly - of course I let my cert lapse more than ten years ago. I do recall that there is a difference with freshwater and saltwater density that affects the rate of pressure/depth change.

Color me curious as to how you are splitting the regulator output to the various target cases - how do you maintain accurate pressure in each case?

Hi Tim !
To answer your question short of going into the "Ideal Gas Laws" or "Dalton's Law" of partial pressures, I'll just be using the one regulator. I could use an individual regulator on each axle and gear box to compensate for the rise in temperature of each unit but since the military did not feel it necessary, I didn't either. I personally believe we are good to go with just the one regulator. Since it is not a "sealed" system (leaks will happen) there will be a constant flow of air and the one regulator will be able to handle it fine since it is only 2-3 psi.
The actual "splitting" is done at the air-manifold. There the individual lines converge.

Since your here, how's the "project" going ? I had to fly to Hawaii for Christmas (the in-laws paid) and didn't have any entertainment ! The guy next to me had over 50 movies on his lap-top but he wouldn't share !
Talk with you later.

 

[Another Ahab]

I had to fly to Hawaii for Christmas

A trip to Hawaii. An earthly paradise.

AND, on the house.

Oh, the pain, the suffering. The humanity!


https://en.wikipedia.org/wiki/Herbert_Morrison_(announcer)#

 

[joeburks]

Great Thread. I'm on day one of bobbing a M35a3. My favorite camping spot requires five river crossings. Every year I go through the ritual of greasing and changing all the fluids on my CJ7 after the trip. I'm thinking drying out the wheel bearings on the deuce is gonna be a way bigger job than that. I liked the Idea of turning up an LP regulator and using a manual three way valve, but I'm not sure I can get 2.5psi out of it. They are factory set at 14" water column (0.51 psi.). After the air dumps in to the wide open space of the gear boxes I wouldn't think surging at the regulator would translate to much variation at the box. Do you think the flow control is really necessary? In my case I'm assuming I really don't need to do anything with the automatic transmission.

 

[Another Ahab]

Great Thread. I'm on day one of bobbing a M35a3. My favorite camping spot requires five river crossings.

Five river crossings?

How in the name of Sam Hill did you find that spot in the first place!?

(PS Just noticed you look sort of new here, so welcome from up here in Virginia!)

 

[icecreamman]

Please excuse me for being possibly ignorant?

Didn't the original "water fording kit" only blow enough air into the bell housing to keep water out with the bottom plug removed? I don't recall anything about the wheel bearings? That being said? Wouldn't you have to have a bottom plug with a small hole drilled in it to maintain pressure ? Trying to maintain 2.5 psi throughout the system with a 1/2 or 3/4 inch plug out would be a little difficult.

 

[icecreamman]

Cant remember the plug size, still impossible?