A Regulator for All Seaso... er, Engines

[larry cottrill]

This is especially for those who have claimed over the years that "you can't use a regulator -- it's too restrictive". I recently got this one for a client who wants to run a fairly big engine from a couple of those forklift propane cylinders manifolded together.

This is the ESAB model R-6701 Station / Line Regulator. It is significantly larger and MUCH heavier than a typical welding regulator, and the ports are designed for very high flow. The inlet and outlet taps are 1/2-inch NPT in lieu of the "standard" ones; I had to use a bushing to get down to the thread size for a standard propane barb. The reason this regulator is a good choice: At 200 PSIG inlet pressure and an output pressure of 15 PSIG, delivery is OVER 100 CuFt/minute !!! In case of possible flameout, you DO NOT want to leave the throttle valve unattended!

Unfortunately, for this first post, I don't have a photo of the whole assembly with the barb and throttle valve attached, but I'll get that later. I'm waiting for a nifty John Deere throttle knob to dress up the valve lever (and make it safer and more user friendly).

Since I was only buying one for the client's prototype testing, I paid retail, naturally -- a mere $236.00 US for the regulator by itself, brand new from the local weld shop. The red line on the acetylene gauge is pretty silly for propane, of course, but there was no real point in adding more expense by swapping it out for a plain 0-30 PSIG one.

L Cottrill

[larry cottrill]

All right, this morning I FINALLY got to put the finishing touches on the fueling rig. The gauge as supplied is strangely positioned on this regulator, "upside down" from how it would normally be on a cylinder regulator (such as a welding regulator). But, I decided to leave it that way so that the throttle lever would be perfectly clear for the hand and arm of the operator. To change it, you'd just swap the gauge and plug between the top and bottom of the regulator. With the gauge on top, your wrist and hand would be positioned directly behind the gauge, but not as awkwardly as it might appear.

The throttle knob is a rubberized plastic one I hunted out carefully from some lawn tractor dealers. This is the nicest one I found; a $10 part from John Deere. The first photo shows the lever in the OFF position; the closeup shows it in the FULL power position. The third shot is from the rear, rotated to show the knob on top. The lever is modified by sawing and welding to rotate the entire movement arc above the pipe centerline, and the knob is attached with (what else?) J-B Weld.

L Cottrill

[Kool]

wow, how about fitting the trottle knob to a foot accelerator

My saturday job is by an tractor dealership, I can tell you that you buy nice things for very nice prices (pums, couplings, etc.)

[Viv]

Hi Larry

A big question for me is how will this type of heavy duty regulator perform in the presence of feedback pulse from the engine's inlet? we know standard (cheap as chips) ones tend to shut down under pulsation and do not have enough gas flow any way, I note you have a very nice braided hose too that will probably help those pressure pulses to get to the regulators diaphragm

Do you think you can come up with an easy way to measure flow as well as pressure? if so it would tell us what was going on between a static and dynamic test and if the regulator was affected at all.

Very nice build and up to your usual standard, good luck

Viv

[larry cottrill]

Viv -

Thanks, and I understand your concerns. All I can say is, if it works it works -- if it doesn't, we just couple the nice throttle valve directly to the barb and go with it. HOWEVER, keep in mind this is NOT a single-user cylinder mount regulator. The guts of this unit are WAY heavier than even a big welding fuel regulator, and whatever natural frequency it has must be really, really low. (Of course, the big FWE only does 90 Hz according to UFLOW1D, so who knows?)

I have ALWAYS run my small engines through a similar but smaller high-flow unit (from Victor) and have never experienced any problem (so far as I have been able to perceive it). Braided stainless hose and all. Only an experimental run will tell us for sure, though.

I have never bought a flow meter. There are some fairly nice moderately priced vane type meters that would work. Maybe someday I'll get a couple of those in different ranges. I haven't seen any specifically for Propane, but one for air would probably be close enough for my purposes.

L Cottrill

[ZanderJay]

As part of the regulators, it's better to determine all the purposes of having that kind of regulators. However, it was the interested to think that how could it be much differ from the welding regulator? And then, it’s good to know that the flow are making into worth as for the works.