Denison Information Page 1

 

GENERAL The PV series pumps are variable displacement open loop piston pumps with a design emphasis on operation economy. These axial piston pumps for open loop operation are suitable for rear drive in the PVT series configuration.
  The PV pumps have a displacement of 0.88 to 3.78 cu. in/rev. (14,4 to 61,9 cc/rev.) with a continuous working pressure of 3500-psi (241 bar) except the PV29 which is rated at 3000 psi (207 bar). Intermittent operation at 4500 psi (31 0 bar) except the PV29 which is rated at 4000 psi (276 bar). These pumps can be equipped with a pressure compensator, ventable compensator, load sensing, or power limit control.
  The PV pumps have been designed to operate in a wide range of applications in industries where high pressure and variable flow are required at competitive cost.
OPERATION OF PUMP These pumps have the familiar principles originated for DENISON HYDRAULICS axial piston units.
  The shaft is splined to the barrel, which carries the nine axial pistons. Each piston terminates in a ball on which is swaged a shoe that is free to pivot and rotate. It bears against the cam surface, which is angled to the shaft axis. The opposite end of the barrel lightly bears against the port plate with its accurate openings. These communicate to the ports A & B of the piston unit. The barrel and piston shoes are free to move axially to compensate for wear, for thickness variations of the fluid film and for dimensional changes caused by temperature and pressure.
  The piston shoes are held against the cam surface by the hold-down plate. It rotates at shaft speed and is permitted to adjust to the cam angle by the hold-down ball, which loads it.
  The hanger cam axis, the shaft, and the plane of the piston ball centers all coincide with the center of moments of the unit to give a fully balanced design. This reduces control force and wear to a minimum.
  The angle of the cam surface determines the displacement as well as the direction of fluid flow for a given rotation. The cam surface is supported on a movable hanger. Various controls adjust and limit the hanger angle.
MOUNTING These pumps are designed to operate in any position. The mounting hub and two-bolt mounting flange are in full conformance with SAE standards. The pump shaft must be in alignment with the shaft of the source driver and should be checked with a dial indicator. The mating pilot bore and coupling must be concentric. This concentricity is particularly important if the shaft is rigidly connected to the driven load without a flexible coupling.
SHAFT OPTIONS SAE splined and keyed, see installation drawings page 10 through 19 for details.
INPUT SHAFT INFORMATION Splined: The shafts will accept a maximum misalignment of 0.002" (0.06mm) total indicator reading when the pump is foot mounted and 0.001" (0.03mm) when flange mounted. Angular misalignment at the male and female spline axis must be less than 0.002 per inch radius ± 0.002mm. The coupling interface must be lubricated.
  DENISON recommends lithium molydisulfide or similar grease. The female coupling should be hardened to 27134 Rc and must conform to SAE-J498c, class 5 flat root side fit.
  Keyed: High strength heat-treated keys must be used. Replacement keys must be hardened to 27-34 Rc. The key corners must be chamfered 0.030-0.040" (0.075-1.0mm) at 45' to clear radii that exist in the keyway.
SIDE LOAD CAPABILITY The PV series is designed for inline-drive and side loading on the shaft is not recommended. If this is unavoidable consult your nearest DENISON HYDRAULICS representative.
PIPING Connect inlet and outlet lines to the port block of the pump.
  The maximum case pressure is 10-psi 0.7 bar continuous. Case pressure must never exceed inlet pressure by more than 15 psi 1 bar. When connecting case drain line, make certain that drain plumbing passes above highest point of the pump before passing to the reservoir.
  The case leakage line must be of sufficient size to prevent back-pressure in excess of 10-psi 0.7 bar and returned to the reservoir below the surface of the oil as far from the supply suction as possible. All fluid lines, whether pipe, tubing, or hose must be adequate size and strength to assure free flow through the pump, An undersize inlet line will prevent the pump from operating at full rated speed. An undersize outlet line will create back pressure and cause heat generation. Flexible hose lines are recommended. If rigid piping is used, the workmanship must be accurate to eliminate strain on the pump port block or to the fluid connections. Sharp bends in the lines must be eliminated wherever possible. All system piping must be cleaned with solvent or equivalent before installing pump. Make sure the entire hydraulic system is free of dirt, lint, scale, or other foreign material.

Caution: Do not use galvanized pipe. Galvanized coating can flake off with continued use.
SERVICE INFORMATION These hydraulic products are designed to give long dependable service when properly applied and their systems properly maintained. These general instructions apply to typical systems. Specific instructions for particular equipment can be developed from them.
RECOMMENDED FLUIDS The fluid recommended for use in these pumps has a Petroleum base and contains agents which provide oxidation inhibition and anti-rust, anti-foam and de-aerating properties as described in DENISON HYDRAULICS standard HF-1.
VISCOSITY 90 VI minimum. Higher values extend the range of operating temperature but may reduce the service life of the fluid.
TEMPERATURE Determined by the viscosity characteristics of the fluid used. Because high temperatures degrade seals, reduce the service life of the fluid and create hazards, fluid temperature should not exceed 180'F 8-2'-Q at the case drain.
MAINTENANCE The pump is self-lubricating and preventative maintenance is limited to keeping system fluid clean by changing filters frequently. Keep all fittings and screws tight. Do not operate at pressures and speeds in excess of the recommended limit. If the pump does not operate properly, check the troubleshooting chart before attempting to overhaul the unit. Overhauling may be accomplished by referring to the disassembly; rework limits of wear parts, and assembly procedures. Refer to the service manual for troubleshooting and overhaul information.
FLUID CLEANLINESS Fluid must be cleaned before and continuously during operation, by filters, which maintain a cleanliness level of ISO 17/14. This fluid level cleanliness can usually be accomplished by the effective use of 10-micron filters. Better cleanliness levels will significantly extend the life of the components. As contaminant generation may vary with each application, each must be analyzed to determine proper filtration to maintain the required cleanliness level.


Innovative Hydraulic Designs, Inc. 6830N. Eldridge Pkwy #102 Houston, Tx. 77041Tel: 713.849.2949 Fax: 713.849.5638