Questions about hydraulics.

[rasorbackq]

Just bought a 4x8 trailer with a hydraulic power pack . The seller told me that the dump has problems to dump the load if the load is humped up at the front But if humped up at the rear will dump the load . He was using it to dump loom . So my question is what allows a dump to dump more weight? Is it the cylinder ? I look on line and see all the different sizes of cylinders. They all seem to have the same ratings only the lift lengths are different. If I remove the power pack and rehook to the tractor rear hydraulics will it be stronger?
Best I can tell its a hydro Tek single action . Not the exact unit but a little older Might even be a double action as it makes noise when lowering but don't think its hooked up to power down.



Overview
The single acting power pack can be used for many applications including Aerial Platforms, truck hoists, scissor lifts, compactors, factory automation etc.

Feature(s)

Integrated 12V DC 2-position solenoid directional control valve

Application(s)

Truck hoists, dump trailers, scissor lifts, aerial platforms



Attributes & Specifications
Type Single Acting
Relief Valve Setting 3,000 PSI
Relief Valve Range 1,000 - 3,000 PSI
Flow Rate @ 3,000 PSI .68 GPM
Port Size 6 ORBF
Reservoir Size 1 gal.
Remote Included Yes

Package Dimensions (L x W x H)
20.0 x 10.5 x 10.5 in.

 

[Baby Grand]

Cylinder diameter, pump pressure, system relief valve pressure, linkage geometry, how far forward the pivot pin is on the bed and load distribution (which you noted) will all affect maximum dumping load.

 

[k0ua]

Just bought a 4x8 trailer with a hydraulic power pack . The seller told me that the dump has problems to dump the load if the load is humped up at the front But if humped up at the rear will dump the load . He was using it to dump loom . So my question is what allows a dump to dump more weight? Is it the cylinder ? I look on line and see all the different sizes of cylinders. They all seem to have the same ratings only the lift lengths are different. If I remove the power pack and rehook to the tractor rear hydraulics will it be stronger?
Best I can tell its a hydro Tek single action . Not the exact unit but a little older Might even be a double action as it makes noise when lowering but don't think its hooked up to power down.


View attachment 422691
Overview
The single acting power pack can be used for many applications including Aerial Platforms, truck hoists, scissor lifts, compactors, factory automation etc.

Feature(s)

Integrated 12V DC 2-position solenoid directional control valve

Application(s)

Truck hoists, dump trailers, scissor lifts, aerial platforms



Attributes & Specifications
Type Single Acting
Relief Valve Setting 3,000 PSI
Relief Valve Range 1,000 - 3,000 PSI
Flow Rate @ 3,000 PSI .68 GPM
Port Size 6 ORBF
Reservoir Size 1 gal.
Remote Included Yes

Package Dimensions (L x W x H)
20.0 x 10.5 x 10.5 in.

Cylinder diameter, pump pressure, system relief valve pressure, linkage geometry, how far forward the pivot pin is on the bed and load distribution (which you noted) will all affect maximum dumping load.

The above reply addressed everything I was going to say. But one thing, you mentioned hooking to your tractor hydraulics. Well, you tractor hydraulics flow rate is bound to be much higher than .68gpm, probably by more than a factor of 10. So your dump rate is going to be over 10 times faster, but your relief valve is bound to be less than 3000 pounds so if you believe the specs shown on the power pak, then on any given cylinder and linkage setup the amount it will lift before going into relief will be less than the power pak shown.

It almost sounds to me that the dump trailer was not well engineered if the loading of the trailer to the front with "loom" (did you mean loam?) makes it impossible to lift. In general if you increase cylinder diameter, the cylinder will be able to generate more force for a given pressure developed. But if you increase the cylinder diameter it will take longer to fill that cylinder with fluid for a given flow rate.. Note the power pak shown has a very very low flow rate so the designers probably spec'd a skinnier cylinder to keep the cycle time faster given the wimpy flow rate of the power pak. Of course the skinnier cylinder will develop less force with the available working pressure.

So, take-aways from this lengthy dissertation: Larger cylinder means more force for a given relief valve setting, but larger cylinder takes longer to fill for a given flow rate. Skinny cylinder has less force for a given pressure relief valve setting but it has less volume so it fills quicker for a given flow rate and extends faster.

Pressure relief valves on most of our small tractors are in the 2400-2800 range so less than the 3000 lbs of the power pak, as stated on your spec's. Flow rates on even our small CUT tractors run from around 5GPM to 10 or more GPM. Your Branson, according to tractor data is 8.9 GPM.

 

[J_J]

Main factors would be size of cyl. Max force from a cyl would be at 90 degrees

Pushing angle. As the angle reduces, the force reducess.

Mounting distance from pivot pin.

Strength of trailer frame and bed.

 

[rasorbackq]

Yes I did mean loam I want to dump that trailer loaded with drain rock . SO I guess that I will have to remove the power pack and extend lines to tractor to see if it will lift what I need it to.
At present I do have so stone on hand so will load it up an dsee if I need to do anything at all.

 

[J_J]

What is the presssre difference between the power-pac and your tractor hyd?

 

[rasorbackq]

What is the presssre difference between the power-pac and your tractor hyd?

Not sure JJ. All I can say is I hook up a back hoe to the same lines where the dump traile r might hook up.

 

[bcp]

You didn't mention the trailer or loading depth, but a 4x8 trailer with around a foot and a half of gravel has a load of about 5000 pounds. Not many 4x8 trailers are built for that.

Please post a photo of the trailer with the bed raised so we can see the trailer, cylinder, and dump geometry.

For example, here is a 5x8 dump, 5200 lb axle, 1800 empty, for 3400 lb capacity (disregarding tires). It has a 3 inch cylinder.
About 10 inches of gravel would be maximum capacity.

PJ Trailers - 60" Utility Dump (D5)

Bruce

 

[rasorbackq]

A 4x8 trailer with around a foot and a half of gravel has a load of about 5000 pounds. Not many 4x8 trailers are built for that.

Please post a photo of the trailer with the bed raised so we can see the trailer, cylinder, and dump geometry.

Bruce

This railer is very well built and super heavy. Takes two men to lift the tongue it will have 2 new 9.5L x 15sl balloon tire this week.

 

[bcp]

Farm trailer-different animal.

It looks like the cylinder is positioned so the force at the beginning of the lift is trying to push the bed forward, not up.

Depending on your hauling situation for this gravel, you might put a temporary block under the front of the bed so it doesn't come all the way down. That would give the cylinder a better start for dumping.

Bruce