1. High
pressure pumps operate to 20 000 psi (1380 bar)
The positive-seating action of the check valves provides better
wear and higher volumetric efficiency, especially for high pressure pump
operation from 6000 to 20 000 psi (420 to 1380 bar). During
operation, the checkball rotates, providing a uniform, moving area of
wear. The result is high efficiency even as the checkball wears.
2. Efficient
pressure compensation to 8500 psi (590 bar)
In pressure compensated models, fluid flows through the pump,
back to tank at relatively low pressure. This design provides stabilized
temperatures with little increase in heat, even when compensating for
long periods. Compensated models are rated to 8500 psi (590 bar). Response
to load conditions is quick, assuring full power in the system up to the
compensator setting.
3. Check
valves provide less wear, lower starting torque
The check valves take the place of a valveplate, commonly used
in other pump designs. The metal-to-metal rotating sealing surface in
other pumps is an inherent leakage path, subject to wear and scoring with
lower lubricity fluids and contaminated fluids. The check valves in checkball
design pumps also isolate the pistons from system pressure during startup,
allowing the piston shoes to establish an oil film before pressure is
generated. The result is lower starting torque for longer bearing life.
4. Contamination
tolerant pumps for dirty environments
The outlet check valves provide a relatively large flushing path
for any system contamination. This makes these high pressure pumps ideal
where fluid cannot be totally cleaned by filtration, or where complete
filtration is just not economical.
5. Simplified
multiple-function circuits without flow dividers
Isolated pumping chambers allow the output of each piston to
be used separately. One multiple-outlet Split-Flow® pump can supply
multiple functions in a circuit with separate loads. The result is a simplified
circuit with fewer components and less piping. These pumps can supply
flow for synchronized movement of cylinders or motors, with greater accuracy
than flow dividers. They can efficiently supply flow in a Hi-Lo circuit
with changing flow and pressure requirements.
6. Operate
within a wide range of viscosities and temperatures
The positive-seating check valves provide better wear and greater
volumetric efficiency, especially operating with lower-viscosity fluids
and at extreme temperatures. Various models operate within a wide range
of recommended viscosities from 31.6 to 3 142 SUS (1,5 to 680 cSt).
7. Compatible
with low-lubricity and other special fluids
Pump models are available for use with a variety of water-based,
fire-resistant and other special fluids. The properties of these fluids
include a combination of high or low viscosity with either high or low
lubricity. Compatible fluids include water glycol and other water-based
fluids, Viscor and other calibration fluids, Skydrol and other phosphate
ester fluids, machining coolant, brake fluid and various military fluids.
8. Single-fluid
design eliminates fluid cross-contamination
Internal bearing lubrication is provided by the pumped fluid.
In applications using special fluids, this design eliminates cross-contamination,
which may occur in other pumps requiring a secondary lubrication fluid.
It also eliminates the cost of a lubrication circuit or regular maintenance
of a lubricating oil.
9. Smooth,
quiet operation with resistance to cavitation damage
The outlet check valves do not un-seat until pressure in the
pumping chamber rises to load pressure, providing inherent resistance
to cavitation. The formation and collapse of vapor pockets in other pump
designs causes vibration and premature wear of metal surfaces. The reduced
decompression shock in checkball pumps contributes to smoother and quieter
operation (as low as 63 dBA), especially at high speeds and pressures.
Sound generated is typically a less noticeable, lower pitch.
10. Bi-directional
shaft rotation reduces pump stocking requirements
Fixed displacement pumps provide constant direction of output
flow regardless of drive shaft rotation. This can be an advantage when
using double-ended electric motors, requiring only one model to be stocked.
| Dynex/Rivett
Inc. Pewaukee, WI USA Ashland, MA USA Eaton Socon, Cambs. UK |
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