Hello. I am building a stump grinder for mini ex. Aux flow is 17Gpm . Yes I know it will be slow/ not super powerful. The hydraulic motor i have does not free spinning (not the right term ) I thinking of adding a cross over relief valve at the attachment. Found this at Princess Auto. https://www.princessauto.com/en/detail/30-gpm-cross-over-relief-valve/A-p8689226e Princess Auto is canadian version of harbor freight . Would this allow blade / motor to free spin to naturally slow down when not powered?
What you need is a motor spool in the control valve to allow spin down. A motor spool in the neutral position has open ports that allow oil to flow freely to and from the hydraulic reservoir.
a simple solution is to use a check-valve from the pressure side to the return side on the implement just before the hyd motor -installed so the arrow (usually indicates the direction of free flow) points back to the pressure side which will allow the hyd motor to freewheel and wind down after the control valve flow is stopped. it should be the same size as the hyd hoses. I would assume the hoses are 3/4 or 1". a suitable check valve can be bought through a hydraulic shop from a knowledgeable parts person( which may or may not be found at princess auto). I think the last one I got from a hyd shop was about $60 for a 3/4 npt version
the cross-over relief valve should also be used to protect from shock-load- it alone will not let the motor free-wheel
How much psi does your miniex make? Just from a GPM standpoint, I think it will be not only slow but likely not worth the effort. PSI would be an important aspect as too low and you will constantly go over relief, combined with low RPM, I don't see this being very viable. My opinion of course.
Perfect about simple check valve suggestions. Mini ex 2950 psi..... Thxs guys
HI Guys Stuck out of getting simple check valve. Local Hydaulic shop recommends : Parker DSL102N + B10-2-A8T body and CAP012D coil. It is two way normally open so you would hook that up between the two lines going to the motor. With the valve open/de-energized, the motor will free spin. Energize the valve to close it and the motor will operate via the auxiliary valve on the bobcat. See spec attached. This seems way too complicated and expensive. There are few company's in states that sell my exact set-up here is a youtube video with comparable mini ex to prove it should work. But 1 they dont have disturber in canada and 2 with the Canadian Peso/Value it would be over $10K ! If I can solve this cross over value/ check system for $100 I will have less than $1k canadian in materials...
Is the problem you can't find a supplier? Princes Auto sells 1/2" check valves online. Motion Industries has 3/4" online: https://www.motioncanada.ca/productDetail.jsp?sku=00276055 Or ebay... https://www.ebay.ca/itm/Hydraulic-check-valve-3-4-NPT-Pump-Oil-3000psi-no-return-valve-single-way-US/262144149963?_trkparms=aid=222007&algo=SIM.MBE&ao=2&asc=20180124145912&meid=7a8e9ce711f0482cbf9bf786af87c02e&pid=100005&rk=4&rkt=12&sd=262211593958&itm=262144149963&_trksid=p2047675.c100005.m1851 As for DSL102N + B10-2-A8T body and CAP012D coil combo, the total cost is $110US plus shipping from the first google hit that came up (partsgopher). Doesn't seem that expensive or complicated. The only thing is that the valve they quoted you (DSL102N) only has a flow rate of 8 GPM. https://tejas.hyd.com/uploads/5/2/5/7/52570035/svsection_2w2p_dsl102.pdf
Thxs Greg. I am owner/operator, have not rapped my head around hydraulic yet... I thought I looked at Prin Auto, show link to my fabricator and he said that would not work. Local Hydraulic supplier who sold me the motor recommended the DSL102N + B10-2-A8T body and CAP012D coil combo verbally said $300 to $400. So nice if the local supplier to spec 8 gpm when we need 17 gpm That is seem expensive, I did not find the ebay valve when I searched. The complicated part would be adding a 12 v controled circuit. Just one more thing to add to machine and latter brake or be damaged. Will the ebay check valve allow the motor to free spin down?
Have you looked at https://baumalight.com/stumpblaster/en/ex-s18.php ? They are made in Ontario. You should look over their motor options as they show displacement suggestions for various flow rates. They also have a chart that shows flow rates for various machines under load, which may not be what you think your machine actually has. Also you can see they use a relief valve on their grinders.