Problem w/ Haskel mini-booster not cycling

tomhanaway

Ok, several months after purchasing, I finally set up my Haskel mini w/ fittings that work.
The unit works fine for flowing from source tank to small rebreather tank. Basically just a transfill.
However, when I activate the booster w/ air power source (compressor at 100-125psi) I only got about six pumps then no compressor action while gauge on receiving tank is showing about 2300 lbs. Source is about 2800 lbs in a 120 cf bottle.

Is there an adjustment needed (some sort of internal pressure on the booster??) so that it runs with my compressor?? If so, where is it?
If there are no whips connected/pressure in the in/out lines, the compressor cycles fine.
Tom Hanaway

Barrie Law

Hi Tom,

The Booster is designed to have a maximum air drive pressure of 150 psi and it sounds to me like the air drive pressure is insufficient to drive the Booster.

If the problem was in the head or the non return valves you would not have been able to equalise the pressure between your supply tank and your fill tank.

For a quick test can you supply the Booster from an air diving cylinder with a standard regulator fitted to control the inter stage pressure and drive the Booster with the low pressure whip to determine if the problem is in the Booster or the air drive compressor.

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diverreb

Does it work when you drive it with HP air from a Scuba Cylinder?

It's possible that the compressor you are using does not generate enough volume to drive the booster. At 100 PSI the booster barely works and you my need a lot more CFM to drive it. Mine sucks a ton of air when it's boosting to higher pressures driving it off a set of double 100's.... Also it's definitely not the right tool to use for boosting to a large tank. Boosting to a 40 CF tank takes a while... It would take forever to do a 120 CF bottle.... It's just not designed for that.

My Haskel seems to run best with the intermediate pressure set at 135 - 140. Anything above that and the OPV on the Haskel blows off. It's not supposed to blow off until it passes 150, but mine blows off before that. I get about 10 - 12 cycles per minute at that pressure & volume if I remember correctly.

Richie

tomhanaway

That's sort of what I figured. I'll check by using a dive tank for drive gas tomorrow. I was hoping to avoid having to buy another garage compressor w/ a higher psi rating.

Does lowering the IP of the Haskel unit lower the required drive pressure?
If so, which valve on the compressor would I play with (says the evil scientist w/ intermediate pressure gauge in hand).
Tom

diverreb

There are no adjustments for that on the Haskel.... I adjust it on my first stage regulator. I also plumbed in a quarter turn ball valve on the drive gas input on the Haskel in case I need to drop the flow or pressure.

While the PSI is an issue the SCFM (Volume of gas pumped) is probably more important. A high PSI with a low flow rate won't do you much good. Most of the Shop compressors I looked at were only pumping about 4 or 5 SCFM at 90 PSI and the SCFM dropped as the PSI increased. which doesn't sound like it would work very well, but there are some other guys using them to power their boosters.

Here's the one I looked at.... It's rated at 6.4 CFM at 90 PSI. I have no idea if it will do the job or not.
Sears.com

Again, the unit is not designed to boost large bottles, no matter what you hook up to it.

Richie

JS1scuba

The key to running your booster is drive volume. It will use upwards of 5 cubic feet of drive air to boost one cubic foot of target gas. I've been driving haskels off doubes for years. The key is to use a high flow regulator, put the ip to 10 bar / 140 psi range and make sure the valve is all the way open. Put a small ball valve between the drive supply hose and drive gas inlet and control from that.

You may also be experiencing "stall" that's where your supply gas and your target gas are either too far apart from eachother AND your drive gas is not sufficient enough to make it work. Also make sure that both your Supply Valve and Targer valve are all the way open before you start to boost, once you start boosting the Haskel controls the flow rate.

Also never remove or modify the Haskel exhaust muffler it is designed specifically to blow cool air over the piston.

We just used a haskel single stage booster for all our work on the Monitor project. We transfilled and boosted close to 8,000 cubic feet of gas (we had a bunch of OC guys and this little booster used about 3,000 cuft of drive gas to get it all done. (25 fills on a set of doubles) my agt 15/30 would have been faster but would have used more drive gas AND taken up 4x the space.

Good luck

JDS

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Hanssing

Hi,
Congratualations on your new booster.
I sounds as if the booster stalls due to drivegas pressue.
Your booster is a single stage, wich makes stall-pressue calculations very easy, since this is what HAskels uses as their boost ratio (a bit misleading, its not how much you can boost from inlet to outlet, but the max pressure you can boost to!).
The boost ratio is the pistion area ratios, and since the minihaskel have a ratio of app. 20, your stall-pressure will be 20 times the drivegas pressue. ie. app 2000-2400psi. Youl have to increase drive-gras pressure in order to boost beoynd that.

Volume-Use of drivegas is also easy to calculate. The drivegas volume per stroke is independant of boostgas inletpressure, and only dependant of output pressure and drive-pistion volume.

I have recently purchased a HII booster, and for this did som calculations on drivegas use, effeciency etc. These are valid for any singlestage booster if you enter the correct dimensions, and includes supply-tank pressuredrop.
Now I think they are right, but not completely sure, and they were done in metric. Anyone care to rewiev?

Note: HII recommends a pressure-increase when boosting of no more then app. 5:1 due to loss of effeciency. This means one should not try to boost 400psi to more than app. 2000psi with a single-stage booster. Instead you could mimic a dualstage booster by scavaging the gas to an intermediate pressue-tank, and then boosting onwards from that.

Regards
Nicolai

Attached Files

Booster 5G-SS-30.zip (9.1 KB, 19 views)

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tomhanaway

In good shape. Drive gas from scuba tank works perfectly.
As to the compressor, my garage one has 125 psi, 6.7 cf per minute at 90 psi. So I will play with shorter, wider hoses and larger fittings to see if I can increase flow over the current 1/4" fittings.
Looking at pricing of larger, 220v compressors, I'll be much better off just using scuba tanks for drive gas to fill my 19 cuft bottles.
Tom

RAL

The 1/4" fittings may not be the problem, sounds more like a volume problem. How about using a larger volume tank on your compressor? You may have to stop & let the pressure build up a few times depending on the size of the volume tank but it may be a cheap fix.

Regards
Ral

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4ster

You might find that a compressor with a higher outlet pressure would be the way to go if powering from a shop compressor. There is a thread covering this in this section entitled "A compressor for running my booster".

I bought a Dewalt portable oil-less compressor that puts out a constant 10 bar (147psi) to my booster (a Jetsam). It works great. Does not overwork the compressor either. If the flow requirements for the Haskel mini are similar to the Jetsam, this might be worth considering.

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