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Slide Valves Hydrl. oil type

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This topic contains 2 replies, has 2 voices, and was last updated by  Walter Stinson 12 years, 10 months ago.

  • Author
  • #2854

    Freddy Martinez

    We are having problems of high operating temperature of the Slide Valves (our ambient is high around 50 deg. C in summery) and we have frequent failures such as cylinders leaks would like to suggest changing my Refinery  RFCC Slide Valves hydraulic fluid from Chemolube to synthetic oil SHC526 as it is excellent for high temperature performance and reduces the servo valves sticking.  This change will solve the Slide Valves failures such as the cylinders leaks, check valves malfunction , high fluid temperature   etc. What do you think about that?
    Thanks, Essa Al-Muqbali

  • #5755

    Walter Stinson

    Your problems are similar to others and your noted problems may be independent but may also be related.
    A) Excess Heat: normally comes from a warn pump or a point of bypassing fluid to tank. If your ambient temps are always high it may be a problem with the water/glycol based fluid (Chemloube) and evaporation of water content. Does your system have any type of heat exchanger?
    b) Changing fluid: There is always a lot of concern when changing from a water/glycol based fluid to a synthetic fluid such as the Mobil SHC500 type. The number one problem would be seal compatibility throughout the system. The second problem would be getting all of the water/glycol out of the system.
    c) Hydraulic Leaks:  Systems utilizing a water/glycol based fluid such as the Chemolube (is this the Chemolube H Special by Hytek?) require seals different than the synthetic fluid noted.
    Who is manufacturer of your system? Who is manufacturer of your hydraulic cylinders? How old is your system? Is Chemolube the original fluid from the OEM? have you done a fluid analysis later to check chemistry (mechanical stability) and contamination levels.

  • #5632


    Let’s talk about Chemolube H Special Fluid. The biggest problem with seals is that this fluid is not compatible with seal material such as a urethane based material. It is also not compatible with VITON. Seal material should be BUNA (Nitrile Based).  Also, the SHC526 may require complete change of every seal in the system so existing seal material must be verified.
    50 Degees C is a fairly high ambient for any type of fluid so a cooler should be utilized. It is important to install the cooler in the correct part of the circuit.
    Sticking servo valves is almost always caused by fluid contamination. Have you completed a fluid smaple analysis to determine ISO cleanilness rating?
    Who is manufacture of your system?
    You may contact me directly in needed. 
    Slide Valve Control Guy

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