Dash Sizes
Dash Sizes
(OP)
So I have a hydraulic system with two cylinders that use a sequence valve. At the start I knew information about one cylinder that used an SAE-6 Fitting. Knowing that I picked a sequence valve that also used SAE-6 fittings, that could operate at the pressure and the flow rate I needed.
I've now got information on the second (larger and longer) cylinder and it has SAE-12 fittings. Does that mean I should change the sequence valve and first cylinder to SAE-12 fittings. I understand the dash 12 is a larger hose and with that there will be less friction, but I need a little guidence on what else to consider.
Thanks
I've now got information on the second (larger and longer) cylinder and it has SAE-12 fittings. Does that mean I should change the sequence valve and first cylinder to SAE-12 fittings. I understand the dash 12 is a larger hose and with that there will be less friction, but I need a little guidence on what else to consider.
Thanks





RE: Dash Sizes
thread71-232971: Dash fittings
RE: Dash Sizes
-6 is nominally 3/8 tube fitting
-12 is nominally 3/4 tube fitting
Ted
RE: Dash Sizes
My question is more based around why would someone make a part with a -12 fitting unless it required a -12 fitting. I don't think they would. So therefore I think I have to at least upsize the sequence valve to a -12 port to meet pressure/flow requirements. I shouldn't have to change the first cylinder -6 fittings becasue the cylinder doesn't require any more flow rate then that.
Can someone with hydraulic experience verify my logic?
I'm checking the flowrates and pressure of the entire system and if I find anything more out I will be sure to post it here.
Thanks
RE: Dash Sizes
Need to know what you are trying to do in terms of system function. I have run larger cylinders at low flow only because I wanted high force at low speed.
Ted
RE: Dash Sizes
I do want a higher flowrate for the larger cylinder. I went through the entire system and calculated the fluid velocity in each hose and pipe section and made sure to keep the velocity within an acceptable amount. A -10 will work for the larger cylinder.
The problem that I'm struggling with in my head is I need to go to the next size sequence valve to reach the necessary flowrates 18.7 GPM, but the valve only has -8 fittings. I calculated the fluid velocity for -8 and believe the fluid velocity is to high. Still the sequence valve claims to source up to 30 GPM. Is it okay for the valve to use -8 because it is only for a short run and then once outside the valve I will jump up to at least a -10?
RE: Dash Sizes
Ted
RE: Dash Sizes
I appreciate being able to bounce thoughts off of you.
Andrew
RE: Dash Sizes
Out of my own curiosity A question... is the larger cylinder doing work during its entire extension?
It is also possible to setup a regenerative circuit by pressurizing both the rod end and cap end of the cylinder at the same time. Thus your only displacing the area of the rod and you can get away with the smaller fitting sizes. After extension you can switch flow to cap end only and get the same force you needed when you selected the larger cylinder.
Just wanted to mention that, you might save some money.
Regenerative advance:
Speed(in/min)=v(Flow of pump in in^3/min)/area of the rod(in^2)
RE: Dash Sizes
The larger cylinder will be doing work the entire extension because it is moving a load. Can you give me an example of an application where a cylinder wouldn't do work the entire extension because it still has to over come some smaller internal forces?
Also what do you mean pressurize both the rod end and cap end? If the cylinder is extending the cap end will be under pressure and the rod end will be returning to the hydraulic tank. Do you mean restrict the flow on the rod end?
Thanks
RE: Dash Sizes
A full description of what you are wanting your system to do would help the forum help you.
Ted