Another breakthrough in undersea technology from Indiegogo!

[tech_diver]

All the time and money we waste on compressors and fill stations, these people can fill a scuba tank with a bicycle pump!

https://www.indiegogo.com/projects/minidive-mini-scuba-tank-refilled-by-the-user#/

Even if we assume a divemaster physically powerful enough to compress 3.5 cubic feet of air to 3000 PSI with a bicycle pump, they'll need to replace the fill inlet with something other than a 150 PSI shop air connection. 150 PSI in that bottle is probably around a tenth of a cubic foot and while enough for a possible expansion injury, not enough to actually swim around.

OK, so if we replace the fill inlet with a high pressure yoke fitting and genetically engineer an 800 pound behemoth divemaster to pump the bicycle pump at .25 CFT per minute at 3000 PSI, it could work right?

Even if the bicycle pump thing doesn't work out, I'd still like to get my hands on one of their compressors. Apparently, it's under 40 pounds and can deliver 1.5 cfm at 3000 PSI from a 12 volt inverter. Sweet!


Discuss...

 

[emoreira]

Though the idea of a mini scuba tank that can last for 5 to 10 minutes is a nice device, it would be the same as a Spare Air used for snorkeling.
As you mentioned, the hand air compressor is the weak (or impossible) point in all this. To inflate such a tank to 3000 psi with a hand pump can take, with a correctly designed hand pump, perhaps two days of pumping as the limit factor is the force that a human can exert to compress the air.
Consider that a man can push the handle of the hand pump with a force of 50 pounds. To produce 3000 psi, with a force of 50 pounds, the area of the piston inside the hand pump has to be of 10,75 square milimeters. Suppose that the piston of the hand pump has a stroke of 200 milimeters. Each stroke of the piston will pump 2150 cubic milimeters or 0,000076 cubit feet. If the tank has 3,5 cubic feet of volume, the hand pump needs to cycle 46085 times. Suppose that you can make 100 strokes per minute, you will need 461 minutes pumping, this is 7 hours and 41 minutes.
Those figures are theoretical. Add all the inefficiencies of a hand pump. Add that no one can pump 100 strokes per minute with a force of 50 pounds for 7+ hours.

 

[dmaziuk]

First of, you're wrong: hand-pumping time from completely empty to completely full is 15 mins (* 30 mins average counting the cooling time). More importantly, for only $1400 you will receive a compressor capable of filling up the 3.5 cf bottle to 3000 psi in 2 min 30 sec. Gotta wonder how long it'd take on an AL80... and if it were for real: what could possibly go wrong?

 

[kelemvor]

We divers aren't the only folks using high pressure compressed air...

It's not a bicycle pump, it's a multi stage high pressure hand pump. HP Hand pumps have been around for a while. Here's one on amazon for $131 with free shipping Amazon.com : Benjamin High Pressure Hand Pump : Hunting And Shooting Equipment : Sports & Outdoors They're commonly used for air rifles (my daughter used to shoot).

Throw in a 3cuft tank, regulator and badaboom badabing!

Options for some guages or an electric pump.

Nice way to package existing products for a good markup. Since he's already scored almost $80,000 obviously there IS a market for it.

 

[KeithG]

maybe i am a little naive, but i would be interested in a hand pump that is rated to 3000psi.

i own 2 manual pumps. the first is for my car tires and it achieves 50 psi. 60psi never. that is why i own a second hand pump for my bicycle tires. it is rated to 130psi and easily achieves almost 110psi. on a good day.

show me the pump!

 

[kelemvor]

maybe i am a little naive, but i would be interested in a hand pump that is rated to 3000psi.

i own 2 manual pumps. the first is for my car tires and it achieves 50 psi. 60psi never. that is why i own a second hand pump for my bicycle tires. it is rated to 130psi and easily achieves almost 110psi. on a good day.

show me the pump!

I should mention, I've never actually used one of these. It's far cheaper to cart around an al80 and a whip. Especially if you are a diver.

Amazon.com : Benjamin High Pressure Hand Pump : Hunting And Shooting Equipment : Sports & Outdoors


One of the reviewers of that pump says "1800 psi to 2800 psi in around 85 to 90 pumps"

That's a lot of work, but it CAN be done.

It says they have a patent. I'm not sure what they actually invented here.. maybe the harness - although it looks a lot like the harness rescue guys use... It might just be a patent that wouldn't stand up to any kind of prior art challenge.

 

[Fossil_Diver]

"...the product is intended for non-divers..."

Scuba equipment for non divers. It comes with safety instructions. What could go wrong?

 

[emoreira]

First of, you're wrong: hand-pumping time from completely empty to completely full is 15 mins (* 30 mins average counting the cooling time). More importantly, for only $1400 you will receive a compressor capable of filling up the 3.5 cf bottle to 3000 psi in 2 min 30 sec. Gotta wonder how long it'd take on an AL80... and if it were for real: what could possibly go wrong?

If I'm wrong, show me your numbers.
If you are right, why that stupid people from BAUER builds stupid air compressors that take 25 minutes to fill an empty AL80 tank to 3000 psi with an electric motor of 3.5 HP.

 

[Captain Swoop]

Air Rifle charging pumps for precharge air rifles. Some will do up to 250 bar.
Airgun buyer, Blackpool Air rifles and Airgun products Air pistol supplies and accessories

 

[Captain Swoop]

"...the product is intended for non-divers..."

Scuba equipment for non divers. It comes with safety instructions. What could go wrong?

Look at some of the home made horrors on Youtube,