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  1. #61
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
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    362

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    Load check (or over centre) valves have been pretty much standard fitment to anything hydraulic lifting a load or people for about 25 years.
    In most situations a secondary pressure is required to operate them.

    You can get in line ones that operate off flow rate. If the line bursts the flow rate increases pushing on a spring loaded piston closing the port stopping flow. There are also others that don`t fully stop flow but restrict flow so that the load comes down slowly.

    DSC06329 e.jpg

    I use these ones on my engine crane and body roller. If the hose bursts flow stops. There is an internal bypass port that can be opened by adjusting a screw to let the load down.

    Tony

  2. #62
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
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    2,651

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    Thanks Tony. An inline valve would be a simple solution.
    Since its only a low flow system anyway I wouldn't expect any issues with it moving too quickly and false triggering the valve.
    Any chance you could grab a part number or something off one of your valves so I know exactly what I'm chasing rather than going to the local hydraulics place asking for a "load valve thingy"

    Steve

  3. #63
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
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    362

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    The part number is Caterpillar 9U-7464. They are used on their 50 -100 ton axle stands. They are for low flow (approx 5 l/m), high pressure (10,000 psi) circuits. Will not be cheap.


    The circuits I use them in are 1500 psi with a flow rate from 2-4 l/m at no pressure. I am not sure they would be usefull for your needs.


    I only just realized that your ram works back the front with lifting pressure being applied on the rod side.

    Tony

  4. #64
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

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    I would concur with BTS, those valves will not suit your application.
    To fit load check valves, the normal method is to mount them on the cylinder and plumb hard lines from the load check valve to the cylinder ports, then hoses from the check valve to the existing control valve. Naturally, being hydraulics this cost far more than it should.
    My twisted, tortured mind has come up with another potential solution that will work provided your machine has electric power (either 12 or 24V will do). This solution will not pass any OH&S legislation, but the rest of your machine wouldn't either. There is a valve called a CBS valve that must be fitted to the hoist on tipper trucks that only allows fluid to flow if there is an electrical signal to the solenoid mounted on the valve (there is also an air operated version). A simple button mounted on top of the control valve lever that was pressed whenever raising or lowering was required would work. CBS valves are not extortionately expensive and could fit to the cylinder with a simple nipple so as to avoid extensive re plumbing.

  5. #65
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
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    2,651

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    Quote Originally Posted by Karl Robbers View Post
    I would concur with BTS, those valves will not suit your application.
    To fit load check valves, the normal method is to mount them on the cylinder and plumb hard lines from the load check valve to the cylinder ports, then hoses from the check valve to the existing control valve. Naturally, being hydraulics this cost far more than it should.
    My twisted, tortured mind has come up with another potential solution that will work provided your machine has electric power (either 12 or 24V will do). This solution will not pass any OH&S legislation, but the rest of your machine wouldn't either. There is a valve called a CBS valve that must be fitted to the hoist on tipper trucks that only allows fluid to flow if there is an electrical signal to the solenoid mounted on the valve (there is also an air operated version). A simple button mounted on top of the control valve lever that was pressed whenever raising or lowering was required would work. CBS valves are not extortionately expensive and could fit to the cylinder with a simple nipple so as to avoid extensive re plumbing.
    Thanks Karl - sounds like a practical option. Machine is 12v so no issues there.
    I had a quick look online and can't find any of those valves jumping out at me so might make a visit to the hydraulics place near work tomorrow and see what they've got.

    Steve

  6. #66
    Join Date
    Jun 2010
    Location
    Canberra
    Posts
    1,322

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    Something like this could do the job:
    https://www.flowfitonline.com/hydrau...ck-vrfu-14-bsp

    Full flow when lifting, restricted flow (adjustable) when dropping. However it's worth noting that it's not pressure-compensated, so a heavy load will drop faster than a light load.

    Also, while this is a UK supplier, if you're getting a quantity of hydraulic bits, they often turn out much cheaper than the local hydraulics shop, even after freight halfway around the world.

  7. #67
    Join Date
    Sep 2010
    Location
    Lebrina
    Posts
    1,910

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    Quote Originally Posted by OxxAndBert View Post
    Thanks Karl - sounds like a practical option. Machine is 12v so no issues there.
    I had a quick look online and can't find any of those valves jumping out at me so might make a visit to the hydraulics place near work tomorrow and see what they've got.

    Steve
    This is the type of valve. https://www.oilpath.com.au/oilpath-p...t-check-valve/
    We used to get all our tipper kits from Gough transport Solutions, but I can't see these valves on their website however I will stake my life on them still stocking them as they have been a legal requirement on truck and trailer tippers for many years. Interesting how few have them fitted though.

  8. #68
    Join Date
    Nov 2017
    Location
    Geelong, Australia
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    57
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    Life is good when the boss gets some use out of my tools

    Captured here collecting a couple of bits from a tree the neighbor felled. To be used in her garden somewhere...





    Steve

  9. #69
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
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    The grandkids have named it "Mater" after the tow tuck in the "Cars" movies
    Yesterday Mater got an engine oil/filter change and Today we finished off a couple of jobs we had to do together, so I pulled off the 2 selector to ram hoses so I can get replacements made.
    Dropped the hydraulic filter so I can grab a new one.
    Didn't expect to find it looking like this:



    Time for a decent flush and new oil as well I think!

    Steve

  10. #70
    Join Date
    May 2011
    Location
    Murray Bridge S Aust.
    Age
    71
    Posts
    5,942

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    It's a wonder it managed to do any lifting. That is GROSS
    Probably still the original filter.
    Nice to see the boss using it too, makes it that bit more justifiable.
    Kryn
    To grow old is mandatory, growing up is optional.

  11. #71
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
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    362

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    It might pay to strip the ram as well to check for sludge and inspect the seals.
    A lot of hydraulic systems use a strainer or course filter on the suction side. (If its a well set up system there might be a fine filter on the return to tank line to filter out the fine material).
    I have seen the suction filters sucked in and damaged because they have become so blocked allowing material to be pumped through the system.
    Remember new lines are good. Anti-burst vales add another step up. But if the seals fail its all to no avail.
    I pays to check everything.

    Tony

  12. #72
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    Nov 2017
    Location
    Geelong, Australia
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    That's the suction filter. No filter on the return side unless it's hidden inside the selector or tank.

    Steve

  13. #73
    Join Date
    Apr 2012
    Location
    Healesville
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    2,129

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    Quote Originally Posted by OxxAndBert View Post
    That's the suction filter. No filter on the return side unless it's hidden inside the selector or tank.

    Steve
    Might be a good idea to fit one of these on the return, between the valve and the oil tank.
    Something like this with a hydraulic filter screwed on.
    https://www.ebay.com.au/itm/New-Univ...0AAOSwuY1dbgQ6

    They are fairly easy to make tho if you want a bit fun in the shed https://metalworkforums.com/f303/t20...14#post1932414

    cheers, shed

  14. #74
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    Aug 2011
    Location
    Perth, Western Australia
    Age
    67
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    362

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    Usually the suction filter will be in the tank with the return filter (if any) being external.

    Tony

    PS Forgot to mention, that creamy stuff indicates water is in the system. Check the bottom of the tank for rust, and check the ram there could be corrosion on the cylinder bore.

  15. #75
    Join Date
    Nov 2017
    Location
    Geelong, Australia
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    57
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    Quote Originally Posted by bts View Post
    Usually the suction filter will be in the tank with the return filter (if any) being external.

    Tony

    PS Forgot to mention, that creamy stuff indicates water is in the system. Check the bottom of the tank for rust, and check the ram there could be corrosion on the cylinder bore.
    Yes, definitely water involved to grow that snot for starters, and there was separated water in the gunge that came out of the filter bowl.

    I hear what you are saying about the need to check everything in the system, but at the moment I'm trying to draw a line and avoid turning it into a complete system strip/overhaul. I will pull the ram off and drain/flush as best I can before it goes back together but won't strip it. I can see the piston rod has some small rust pits so I'm pretty sure that as soon as it comes apart its going to turn into either a full overhaul or replacement. At that point I might take the opportunity to redesign things a bit - ie using the extend side of the ram for the lift for starters

    Current plan is to just disconnect/flush everything as best I can and give the tank a good cleanout then new oil, pressure hoses and filter. The tank has a decent size access plate on the top so should be reasonably easy to get into.

    Eventually ID'd the filter (geez I hate when people hit a whole machine with the spray gun without bothering to mask useful info like filter ID's and data plates etc!!). Its a Parker filter, but equivalent to a Baldwin PT9140.
    Have ordered one of those.

    Steve

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