Hyd load tester

[J_J]

How accurate would this gage and cyl assembly be.

Made by one of the TBN members.

Should it have a plug in the base end port?

 

[CJONE]

How accurate would this gage and cyl assembly be.

Made by one of the TBN members.

Should it have a plug in the base end port?

I would say it should be very accurate once you set up a baseline for pressure. I would vent it with a sintered bronze vent, it should hardly move at all beings fluid does not compress. The oilfield uses almost the same setup for weight indicators. Give me the bore and I can give you force [lbs] per psi. CJ
OH duh I need the rod size to deduct for area, almost screwed up again!!!

 

[J_J]

Don't know any of the data, as another TBN member built this unit.

Compute something for 2 in cyl and 1 in rod.

 

[CJONE]

Don't know any of the data, as another TBN member built this unit.

Compute something for 2 in cyl and 1 in rod.

100PSI=236LB 200PSI=471 500PSI=1178 1000PSI=2356 2000PSI=4712
I don't know what the cyl is rated for but you can go from there. CJ

 

[Zebrafive]

Plug may be drilled to vent and not show in the picture.
Square inch of piston area minus rod area times gauge reading should give weight hanging off cylinder.

 

[IceStationZebra]

I would say it should be very accurate once you set up a baseline for pressure. I would vent it with a sintered bronze vent, it should hardly move at all beings fluid does not compress. The oilfield uses almost the same setup for weight indicators. Give me the bore and I can give you force [lbs] per psi. CJ
OH duh I need the rod size to deduct for area, almost screwed up again!!!

Hydraulic fluid is compressible, though it is usually ignored. The ratio of a fluid's decrease in volume as a result of increase in pressure is given by its bulk modulus of elasticity. For hydrocarbon-based hydraulic fluids it is approximatly 0.4% per 1,000 PSI.

And because of this friction will decrease the accuracy some, though that will depend on the seals.

ISZ

 

[olde man]

enerpac makes a similar set up and they are pretty accurate. i have also made similar ones only larger and they worked quite well. there are also some pressure gauges that take some of the guess work out of it for you, enerpac gp and gf series gauges. but on a rig like this as long as you know your area. the most we were ever off was 3% on a larger cylinder and pretty high pressure.

 

[olde man]

i do suggest calibrating with a known weight something significant.

 

[CJONE]

Hydraulic fluid is compressible, though it is usually ignored. The ratio of a fluid's decrease in volume as a result of increase in pressure is given by its bulk modulus of elasticity. For hydrocarbon-based hydraulic fluids it is approximatly 0.4% per 1,000 PSI.

And because of this friction will decrease the accuracy some, though that will depend on the seals.

ISZ

In this application I am sure .4 will not make a difference. An you are right it is usually ignored because of being so small of a amount, most gauges are off by more than that. CJ