hydraulics question

kaiser715

Doing hard time
Joined
Jun 1, 2006
Location
7, Pocket, NC
Anybody know stuff about hydraulics??

I have a Monarch M-303 12v hydraulic power unit. It is vertical mount, and the smaller ~1/2 gallon reservoir model. From the specs, it looks like it is 1 GPM.

I need to use it in an application, it will be set up sort of like an engine lift, using a cylinder like this:

http://www.northerntool.com/shop/tools/product_200442454_200442454

That is a 2" bore, 24" stroke. I can't find any info on how stroke relates to the oil capacity of the unit...how much the cylinder itself displaces. Haven't had a math course in 30 years. I can use a shorter stroke cylinder, even like a 12"...I just need to figure out what would work.

Edit: it looks like the light-duty cyl that came with it is set up for single-action...it was set up for power up, gravity down...but the cyl does have 2 ports...upper port has a plastic return hose (definitely not a pressure hose)....so it looks like I could maybe use a DA cylinder...it looks like that upper hose pulls/empties fluid to the back side of the cylinder...so I'm thinking the net/net fluid in and out of the tank should be about equal. Maybe?

At 1 GPM, I'm guessing speed of a 2" bore cylinder would be OK...not too fast, certainly not too slow. Right?

Alternative, I have another power pack that came off a wrecker, but it doesn't have the solenoid/valving of the 303, so I'd have a heck of a lot more money in a spool valve, etc.

Any tips/ideas/help is appreciated!

DP
 
Last edited:
The M303 power unit:

asanlee.smugmug.com_photos_i_V6HqbZ2_0_L_i_V6HqbZ2_L.jpg



The unit off a wrecker:

asanlee.smugmug.com_photos_i_6vKNrPB_0_L_i_6vKNrPB_L.jpg
 
Thats gonna be really slow at 1 gpm.

If it's advertised as a pressure up & float down then the plunger seals are only one way. do not pressurize the float side.

You can change the plunger seals to convert it, however your better off getting a 2 way cyl.


Here is a calculator

http://www.bbhydraulics.com/cylindercalulator1.html
 
Slow is good...if it is more or less the same speed as hand-pumping an engine hoist, it will be fine.

Thanks for the calculator, that's (part) of what I need to know.
 
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