Compact Hydraulics

Compact Hydraulics

Fluid Power Systems	These compact fluid power units let you put the power where you need it. They are completely self-contained with motor, pump, reservoir, internal valving, load hold checks and relief valves. They often eliminate the need for other components and plumbing in the system which keep costs down.
108 Series Hydraulic Power Units	The 108 series models are designed for intermittent service and come in four standard pump sizes. Units are available with single or bi-directional rotation and a choice of several hydraulic circuits.
165 Series Hydraulic Power Units	The 165 Series are completely self-contained with a DC motor. These units are designed for intermittent duty and are available in three standard pump sizes.
550 Fluid Power Systems	The 550 Series offers top-quality industrial power in an economical package. The wide range of Parker cartridge and D03 directional control valves available provide great flexibility in offering a hydraulic power unit to match your system requirements.

Piston Pumps	These fixed displacement axial piston pumps are efficient and powerful. Applications requiring compact power; including automotive, marine, medical and military uses. It's compact size, versatility and speed are combined in these cost competitive pumps.

PARKER OILDYNE COMPACT HYDRAULICS

108 Series Hydraulic Power Units

Description:

Pressures to 241 bar (3500 psi)
Flows to 2.8 lpom (3/4 gpm)

Typical Applications

Standard Product Ordering Code

Thermal Relief

Valves —Why?

The thermal relief valve’s (TRV) purpose is to allow a bleed off of built up pressure due to thermal expansion of the fluid or to act as a (limited) shock load protection, should a cylinder in the system get bumped.

The thermal relief valve is included in circuits using a pilot operated check valve. The single direction units get one; the reversing units get two. It is located between the check valve and the 108 Series pump outlet port. It is a fixed relief valve with a pressure setting approximately 100-140 bar (1500-2000 psi) above the system relief valve pressure.

	Back Pressure Circuits—Why?
	The basic reversible circuit is essentially a closed loop. The oil returning from the system is fed back into the pump inlet. When a cylinder is being retracted more oil is being returned to the power unit than is leaving it due to the rod volume. This results in the DN side relief valve cracking open allowing the rod volume of oil to go back to the tank. The larger the rod volume the more open the relief valve will be. In many applications this is not a problem. However, if work is being done on the retract stroke, or if a pressure switch is used to signal the cylinder is fully retracted, the back pressure circuit is required. This circuit allows the rod volume of oil to return to the reservoir through a special shuttle spool, before it reaches the pump. Full relief valve pressure is then available to retract the cylinder, also preventing a pressure switch from tripping before the full retract position is achieved. Recommended uses: • In systems where work is being done on the retract stroke • Where a pressure switch is used to signal the full retract position • In systems requiring a faster retract than extend speed

165 Series Hydraulic Power Units

Description:

Pressures to 241 bar (3500 psi)
Flows to 5.4 lpom (1.4 gpm)

Features & Application

Standard Product Ordering Code

Thermal Relief

Valves —Why?

The thermal relief valve’s (TRV) purpose is to allow a bleed off of built up pressure due to thermal expansion of the fluid or to act as a (limited) shock load protection, should a cylinder in the system get bumped.

The thermal relief valve is included in circuits using a pilot operated check valve. The single direction units get one; the reversing units get two. It is located between the check valve and the 108 Series pump outlet port. It is a fixed relief valve with a pressure setting approximately 100-140 bar (1500-2000 psi) above the system relief valve pressure.

	Back Pressure Circuits—Why?
	The basic reversible circuit is essentially a closed loop. The oil returning from the system is fed back into the pump inlet. When a cylinder is being retracted more oil is being returned to the power unit than is leaving it due to the rod volume. This results in the DN side relief valve cracking open allowing the rod volume of oil to go back to the tank. The larger the rod volume the more open the relief valve will be. In many applications this is not a problem. However, if work is being done on the retract stroke, or if a pressure switch is used to signal the cylinder is fully retracted, the back pressure circuit is required. This circuit allows the rod volume of oil to return to the reservoir through a special shuttle spool, before it reaches the pump. Full relief valve pressure is then available to retract the cylinder, also preventing a pressure switch from tripping before the full retract position is achieved. Recommended uses: • In systems where work is being done on the retract stroke • Where a pressure switch is used to signal the full retract position • In systems requiring a faster retract than extend speed