Fluids by qC40ShL

VIEWS: 13 PAGES: 34

									Fluids
Fluids-- Objectives
1. List four functions of the fluid.
2. List five qualities of a good fluid
3. Explain the difference in two types
of crude.
4. Define terms associated with fluids.
Fluids– Objectives
5.   5. Explain the affects of high and
     low viscosity fluids on a system
6.   6. List appropriate practices for
     the management of stored fluids.
7.   7. List appropriate practices for
     the management of fluids in use.
Four Basic Functions of a Fluid
        •   Transmit power- must be a flow
        •   Lubrication
        •   Sealing
        •   Cooling
LUBRICANT FUNCTIONS
   Contaminant Containment
        Dispersant

        Corrosion   Inhibitor
        Detergent

        Rust   Inhibitor
   Heat Removal
        Oxidation   Inhibitor
   Friction Reduction
        FrictionModifier
        VI Improver
TYPES OF CRUDE BASE
   Parafinic
          Naturally Higher VI
          Higher Pour Point
          More Stable


   Naphthenic
          Low VI
          Low Pour Point
          Less Stable
TYPES OF HYDRAULIC FLUIDS
      – Mineral Oil Based
          - Antiwear and R&O
          - R&O
          - Ashless
      – Synthetic Based
          - Fire Resistant Phosphate Ester
      – Water Based
          - Water-in-Oil (Invert Emulsion)
          - Water Glycol
          - Oil-in-Water
Quality of a fluid
   The quality of a fluid/petroleum oil
    will depend on the:
     Type of crude used
     Degree or extent of refining and
      method of refining
     Additives used
To be a quality Hydraulic fluid
it must:
    •   Prevent rust
    •   Prevention formation of sludge,
        and gum varnish
    •   Be Foam resistant
    •   Maintain its own stability and
        thereby reduce fluid replacement
        cost
To be a quality fluid it must…2
       •   Remain stable over a variety of
           temps.
       •   Separate out water
       •   Be compatible with seals and
           gaskets
       •   Conform to special industry
           standards
           •   *Additives 40% +
CHOOSING A HYDRAULIC
FLUID
     – Regular or Fire Resistant
     – Viscosity
     – Viscosity Index
     – Pour Point
     – Oxidation Stability
     – Rust Protection
     – Foaming and Air Release
     – Water Separation
     – Antiwear Properties
Five properties of fluid
Viscosity
Pour Point
Lubrication
Oxidation
Rust and corrosion
Demulsibility
ADDITIVES USED IN
HYDRAULIC OILS
    FUNCTION           ADDITIVE
    Oxidation    Zinc Dithiophosphate

                 Metal Sulfonates
    Rust

                 Silicone
    Defoamer
                 Zinc Dithiophosphate
    Antiwear
Properties of fluid:
Viscosity
The measure of a fluids resistance to
  flow; or an inverse measure of
  fluidity.
Low viscosity (thin) runs fast, high
  viscosity (thick) runs slow.
Viscosity Index (VI)
An arbitrary scale using an empirical
  formula to indicate the effect of
  temperature changes on the viscosity
  changes in lubricating oils; shown by
  comparing Pennsylvania oil that
  measures 100 on the scale to an
  asphaltic oil that measures zero.
  Source: Harcourt Dictionary
A measure of change in thickness over a
  temperature range.
Low number (0-20) means the thickness
  changes a lot with temperature change,
  While a High number (70-100) changes
  a little.
Affect of viscosity on
system
•   High viscosity fluid (thicker)
    •   Increases resistance to pressure.
    •   Increases power output due to friction
    •   Increases temp due to friction
    •   Increases sluggishness or slow to
        operate
    •   Delivers less force at end due to friction
    •   Greater difficulty in separating air from
        fluid in reservoir
Affect viscosity on
system, cont..
•   Low viscosity fluid (thinner)
    •   More leaks
    •   More wear on even seizure under
        heavy loads due to break down of
        oil film.
    •   Pump efficiency may decrease,
        causing slower operation of the
        actuator
    •   Less efficient, causes higher temps
VI Improvers (VII)
   Additives that prevent changes in
    viscosity over a range of
    temperatures
Viscometer
   Device for measuring the viscosity
    of a fluid.
   Used to establish ASE numbers
Properties of fluid:
Pour Point
   The lowest temperature at which a
    fluid will flow.
   Only important in cold temps.
   PP should be 20 degrees F below
    the lowest temp expected
Society of Automotive
Engineers (SAE)
   Winter grad oils and summer oils SAE
    10W 30
   Winter oils—have a W after the number -
    -Number represents the 32 degrees F
   Summer oils– no W, 212 F
   10W– 3500 cPa – 4 F degree
       The range 45 sus to 4000 sus is
        recommended, 150 is recommended for
        industry
   Hydraulic fluid is identified as SUS or
    Centisoke (millimeters squared/sec)
   A temperature may also be given
Properties of fluid:
Lubricating ability
   EP- Extreme Pressure
     Some fluids have EP additives to
      help prevent wear.
     Generally used where there is high
      pressure and high heat.
Properties of fluid:
Oxidation Resistance
    A chemical reaction, first state reaction
     develops gums, sludge, and varnish
    Some oxidation by-products are acids
    Some cause wear, some cause a
     breakdown of seal, hoses, metal which
     then enter the system as a contaminate.
    Heat, pressure, water, and metal to
     metal contact, contaminants, and
     agitation of fluid all make oxidation more
     likely.
Properties of fluid:
Rust & Corrosion Prevention
             Most common is rust (iron or steel
              and oxygen)
             Additives are used that plate the
              metal surface to prevent chemical
              attack.
Properties of fluid:
Demulsibility
   The ability of a fluid to separate-out
    water
   Small quantities of water will not cause
    a serious problem.
       However, too much will cause fluid to
        breakdown, valves to stick, and
        components to wear to quickly.
   Opposite of Demulsibility (separate out)
    is Emulsibility (incorporate into).
       Some additives promote emulsibility
        which prevents moisture from settling in
        on place and thereby causing rust and
        breaking the antirust film on the metal
       Emulsion is a mixture of water and oil
        under pressure.
         Enemies of
         fluid/systems
   Extremes in heat and cold
       For every 20 Degrees over 180
        you half the fluid life oxidized is like
        road tar.
   Examples:
     200 degree operating temp of a
      3000 hour fluid = 1500
     220 degree operating temp of a
      2000 hour fluid = 500
Enemies of
fluid/systems, cont..
   Examples, cont..
       240 degree operating temp of a 2000
        hour fluid = 250
       220 degree operating temp of a 3000
        hour fluid = 750
       200 degree operating temp of a 2000
        hour fluid = 1000
       240 degree operating temp of a 3000
        hour fluid = 375
       260 degree operating temp of a 2000
        hour fluid =
       260 degree operating temp of a 3000
        hour fluid =
Enemies of
fluid/systems, cont..
   Dust or dirt
   Air—Foaming– Compressed or
    otherwise, compressed can enter
    fluid
     Turbulence promotes mixing of the
      fluid with air
     Air may enter through leaks.

     Which side of the pump will air
      enter.
Enemies of
fluid/systems, cont…
   Water or moisture
       How do you know if you have
        water in the fluid?
          Heat a piece of metal and if it
           patters when oil drops on it then it
           has water.
          Where does it enter the system?

   What happens when you drop
    water in a pan when you are frying
    something
Enemies of
fluid/systems, cont…
   Oxygen- oxidation--- heat (each 18
    deg rise in temp doubles oxidation)
    and air cause organic acids to form
    from the chemical reaction.
   Rust and corrosion- rust adds
    thickness- corrosion eats away,
    related to oxidation
TRACTOR INDUSTRY TRENDS
         TREND                          NEED
    Higher horsepower           Increased gear wear
                                  protection
    Higher sump temp.           More thermally stable
                                  fluid
                                 Lower viscosity fluid
    All-weather fluid            and better low
                                  temperature fluidity
    New friction materials      More brake noise
                                  reduction and PTO
                                  clutch capacity
    Finer filters               Better fluid filterability
Fluid Maintenance
   Changing the fluid and/or flushing the
    system cost money therefore it is
    important to keep clean
       Store drums on their side and under roof
       Before opening drum clean the top and
        cap thoroughly
       Use only clean hoses and containers to
        transfer the fluid. Some people use a
        transfer pump with filter.
       Use a 200 mesh screen in the reservoir
       Keep hoses and surfaces clean, they
        cause dirt to collect.
       Follow directions of the maker of fluid or
        machinery for regular drainage.
In use prevention
   Prevent contamination by keeping the
    system tight
   Use proper air and fluid filteration
   Replace fluid at regular intervals to
    prevent it from breaking down. Follow
    the maker directions. Check fluid before
    the expected time to change.
   Keep the fluid at the recommended level.
    This prevents condensation on wall of
    reservoirs
   Repair all leaks immediately
   Change/Check filters regularly
Review Time…..
   Crude oil yields two types of oils, what
    are they?
   ISO stands for what?
   A good viscosity index is ______ number
    and above.
   Detergent in oil will cause oils to
    _________.
   What two types of pumps require greater
    lubrication?
   Fluids that are flame resistance usually
    have one of two base liquids. What are
    they?

								
To top