Air Caster Plumbing

[kicknargel]

I remember learning/hearing/being told that when plumbing air casters, rather than going from the valve to a manifold and branching to each cylinder, one should go from the valve to a tee fitting on the first cylinder, with the air going into that cylinder and tee-ing to the next, and so on. And then loop back to a tee at the valve to complete a circle.

I think it was supposed to make the unit lift more evenly, but I can't articulate an argument as to why. Any thoughts?

 

[Amiers]

If the air is going into the manifold then to each caster I wouldn't see why it wouldn't lift just as easily as the tee n circle setup.

Only thing I can think of is that it would be less lines if you did a circle.

 

[porkchop]

If the cylinders are pretty close together I could see that working. Personally I've had success with the manifold method. It's just important to make sure that the amount of tube between the manifold and each cylinder is the same.

 

[RonHebbard]

If the cylinders are pretty close together I could see that working. Personally I've had success with the manifold method. It's just important to make sure that the amount of tube between the manifold and each cylinder is the same.

If anyone's not appreciating the logic here, extend it to ridiculous distances in your mind and you ought to catch on. Think of some lines from the manifold being 1 foot long and others being 200 feet long where the air would be subject to compression along the length of the runs.
Toodleoo!
Ron Hebbard.

 

[Amiers]

Here is a good video about the manifold and load management

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[BillConnerFASTC]

Well - air caster seems to have two meanings: 1 is a air caster with the inflated donut and the piece moves on air; the other is a pneumatic cylinder or device that is simply used to lift the load by pushing wheeled casters down.

On the first, I only know enough to be cautions and hire someone else to do this, but somewhere it seems I learned that air casters all need to be fed from the manifold directly. That may have to do with the likelihood of uneven loading. If one caster has 100 pounds and the other 200 pounds, I think the heavy one needs more cfm. Here's what I'm talking about:

 

[RonHebbard]

Well - air caster seems to have two meanings: 1 is a air caster with the inflated donut and the piece moves on air; the other is a pneumatic cylinder or device that is simply used to lift the load by pushing wheeled casters down.

On the first, I only know enough to be cautions and hire someone else to do this, but somewhere it seems I learned that air casters all need to be fed from the manifold directly. That may have to do with the likelihood of uneven loading. If one caster has 100 pounds and the other 200 pounds, I think the heavy one needs more cfm. Here's what I'm talking about:


View attachment 14442

@BillConnerFASTC You've told me you attended Stratford decades ago. We had a length of heavy vinyl we kept rolled up back stage to provide a flat, smooth, air-tight surface for our air castered rigs to run on. We always had to tape the leading edge in place when rolling the air casters from the concrete floors onto the vinyl overlaid onto the planked wooden stage deck. One device was always referred to as the "Red Baron" and it was fabricated and used to float the entire stage balcony unit, complete with Soss-hinged access stairs, approximately 50' upstage and into the USC store room. We had a second, smaller, unit referred to as the "Pink Baron" used to move a smaller, lighter, unit; possibly a smaller U/S extension for the main stage balcony but I've forgotten precisely what. These were true air casters where air, and exiting air, served as the caster(s). We also had a great many pneumatic caster jacks, largely from a manufacturer in Stratford, which were normally actuated using pressurized air tanks housed within scenic elements. The Pink and Red Barons both required shop air lines to supply the volumes of air required. These were all regular change-over items when we were running up to six different productions in rep' and rehearsals in the main Festival Theatre.
Toodleoo!
Ron Hebbard.

 

[BillConnerFASTC]

Guessing at that time those were high pressure air casters. When I did a lot of large seat wagons and stage platforms - 21 x 30 and 24 x 36 - I used low high volume air casters. Used a big roll around blower with a big hose.

 

[RonHebbard]

Guessing at that time those were high pressure air casters. When I did a lot of large seat wagons and stage platforms - 21 x 30 and 24 x 36 - I used low high volume air casters. Used a big roll around blower with a big hose.

Low and high are relative terms. To float our "Red" and "Pink" barons we were using a normal air line with normal quick connects carrying 'shop air' with a device to remove oil added to lubricate tools and a secondary regulator to further reduce pressure. Every now and again something would get ran over and trapped under neath and we had to gingerly play games with 'J-Bars' and sliding off-cuts of vinyl under neath to regain lift on all casters and achieve proper flotation. Down the road a few miles in Kitchener Waterloo's Centre In The Square was a much larger air caster installation floating much larger / heavier units with three story high seatng equipped with lighting, aisle marker lights and delayed speakers. I made the drive down for a few crew calls and let's just say there were many problems which I'd prefer not elaborate upon. When things were working, the right crew were available, everything worked well and time was saved. If all the 'planets' were not correctly aligned there were some very troublesome moments.
Toodleoo!
Ron Hebbard.

 

[BillConnerFASTC]

Off a shop compressor is definitely of the high pressure variety. Low pressure is more like a shop vac.

 

[RonHebbard]

Off a shop compressor is definitely of the high pressure variety. Low pressure is more like a shop vac.

I'd be lying to say I can recall this with any accuracy but I think I'm remembering the red and pink barons levitating on something in the area of 15 to 20 PSI. Artec's installation in Kitchener Waterloo's Centre In The Square used a dedicated, higher volume, compressor with much larger, approximately 4" diameter, hoses.
Toodleoo!
Ron Hebbard.

 

[kicknargel]

Well - air caster seems to have two meanings: 1 is a air caster with the inflated donut and the piece moves on air; the other is a pneumatic cylinder or device that is simply used to lift the load by pushing wheeled casters down.

Yes, my bad. In this case, I mean regular casters on pneumatic cylinders to lift the caster up inside the unit and let the unit sit down on its frame.

I worked in a place with giant orchestra shell walls on the air kind of air casters. The back wall was permanent and the side walls were on hinges to fold against the back wall. You could set the shell walls in about 4 minutes, and one person could move them (although not recommended).

 

[BillConnerFASTC]

Here is a good video about the manifold and load management

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I missed this and RO's directly prior as we were all posting about the same time.

Ron's post made the point I was trying to think - that air compresses - unlike hydraulic systems where the fluid does not compress and it equalizes loads quite well.

PS - now we're ready if someone asks about this kind of air caster.......