Hydraulic Unit

On construction-machinery power units, the valve assembly controls motion and safety.

Depending on the application, the following can be used:

• Directional control valves
• Pressure-relief valves
• Pressure-reducing valves
• Flow-control valves
• Check valves
• Pilot-operated check valves
• Counterbalance valves
• Load-holding valves
• Proportional valves
• Solenoid valves

These valves can be used.

Valves can be grouped on a separate manifold or inside a compact hydraulic block.

Power-unit design for mobile construction machinery has to meet conditions that differ from stationary industrial systems.

The design should take the following into account:

• Vibration
• Shock
• Operation on a slope
• Dust
• Mud
• Rain
• Outdoor temperature
• Compact installation space
• Vehicle movement

These conditions should be taken into account.

Connections, tank construction, pump mounting, and valve assemblies should therefore be designed for field conditions.

Excess pressure in a hydraulic system can damage the pump, hoses, cylinders, and other components.

The system should therefore include a pressure-relief valve set to a suitable value.

The relief valve protects the hydraulic components by limiting the maximum permitted system pressure.

In lifting and mobile-machine applications it is important to prevent uncontrolled movement of the load.

Depending on the application, the following can be used:

• Pilot-operated check valve
• Counterbalance valve
• Hose-burst valve
• Overcenter valve
• Load-holding valve

These valves can be used.

On cranes, platforms, and lifting systems in particular, these valves are important for system safety.

On modern construction machinery, the hydraulic power unit can work together with electronic systems.

Depending on the application, the following can be used:

• Pressure sensor
• Pressure switch
• Oil temperature sensor
• Oil level sensor
• Filter clogging sensor
• Flow sensor
• Position sensor

These sensors can be used.

Data from the sensors can be monitored through a PLC, a machine controller, or an operator panel.

Proportional hydraulic systems can be used on construction machinery that needs precise speed and force control.

With proportional valves, the following can be controlled electronically:

• Cylinder speed
• Hydraulic motor speed
• Pressure
• Flow rate
• Motion acceleration

These values can be controlled electronically.

This arrangement is an advantage on modern mobile machines that need precise, stepless motion.

For the power unit to operate correctly, hydraulic lines must be sized to a suitable diameter.

Incorrect pipe or hose diameters can cause:

• Pressure loss
• Heating
• Cavitation
• Noise
• Low system efficiency

These problems can occur.

Suction, pressure, and return lines should each be sized for the system flow.

Insufficient oil supply in the pump suction line can cause cavitation.

Cavitation can cause:

• Pump noise
• Vibration
• Wear on pump surfaces
• Loss of flow
• Premature pump failure

These effects can occur.

The suction line should therefore be kept as short as possible and designed for low pressure loss.

Because construction-machinery power units work outdoors, it is important to protect the frame, tank, and other metal parts against corrosion.

Depending on the application, the following can be used:

• Industrial paint
• Electrostatic powder coating
• Galvanizing
• Zinc plating
• Stainless material

These protections can be used.

Hydraulic power units are tested against their operating conditions before shipment.

Main checks:

• System pressure check
• Pump flow check
• Pressure-relief valve check
• Leakage test
• Filter and connection check
• Motor rotation-direction check
• Oil temperature check
• Valve function test
• Sensor check
• General function test

Güleç Makina can design custom hydraulic power units to suit machine functions and operating conditions.

The main information used in project design:

• Machine type
• Maximum working pressure
• Required flow
• Number of cylinders and hydraulic motors
• Required movement speeds
• Duty cycle
• Power source to be used
• Ambient temperature
• Installation space
• Automation requirements

These inputs are reviewed during project design.

Güleç Makina can design and manufacture:

• Hydraulic power units for construction machinery
• Mobile hydraulic power units
• Diesel-engine power units
• Electric-motor power units
• PTO-driven hydraulic systems
• High-pressure power units
• Multi-pump systems
• Proportionally controlled power units
• Power units with sensors and electronic control
• Compact power units built to the customer project

These units can be designed and manufactured.

Güleç Makina provides hydraulic power-unit design, manufacture, and engineering for construction machinery, mobile hydraulic systems, municipal vehicles, mining, agriculture, road construction, and custom machine applications.