Monthly Archives for October 2012

Multiple Hydraulic Pump Circuits

The multiple hydraulic pump types install two or more pumps in the same housing and use a single shaft to drive. Each pump has its own outlet although in some application one inlet is provided. The pump shown in figure … Continue reading

31. October 2012 by JackSparow
Categories: Hydraulic Pumps | Tags: , , | Leave a comment

Hydraulic Vane Pump Volumetric Efficiency

Vickers Pump Model 25V-T is a hydraulic vane pump which has a 4.81 in3/rev displacement with max speed 1800 rpm and max pressure 2500 psi. The vane pump volumetric efficiency at 1200 rpm decreases from 97.3% at 500 psi to … Continue reading

31. October 2012 by JackSparow
Categories: Hydraulic Pumps | Tags: , , | Leave a comment

Basic Hydraulic Servo Systems

Four basic hydraulic servo systems: 1. Valve motor two servo actuator system or servo motor. 2. Valve cylinder two servo actuator system or servo cylinders. In two servo-actuator systems, the valve is mounted directly on the actuator to avoid the … Continue reading

30. October 2012 by JackSparow
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Hydraulic Gerotor Pump Volumetric Efficiency Characteristic

Hydreco Model 1919 is a gerotor hydraulic pump with 4.53 in3/rev displacement. The pump has maximum speed of 3000 rpm with 2500 psi maximum pressure. The pump volumetric efficiency drops from 92% at 500 psi to 78% at 2500 psi … Continue reading

29. October 2012 by JackSparow
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Hydraulic Variable Displacement Pump

An expensive hydraulic variable displacement pump offers many options for hydraulic circuit design. The pump displacement can be changed using a servo valve to manipulate the actuator speed movement. The open loop hydraulic design as shown in figure above can … Continue reading

29. October 2012 by JackSparow
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Hydraulic Closed-Center System Using Variable-Displacement Pump

The figure above shows a closed-center system with a variable-displacement pump in the neutral mode. When the pump in neutral mode, the hydraulic oil is pumped until it reaches a predetermined pressure level. A pressure regulating valve allows the pump … Continue reading

22. October 2012 by JackSparow
Categories: Hydraulic Circuits | Tags: , | Leave a comment

Hydraulic Closed-Center System Using Fixed-Displacement Pump And Accumulator

This system uses a small fixed hydraulic pump to charge an accumulator. When the accumulator is fully charged, an unloading valve diverts the oil to flow back to the reservoir. The oil pressure is trapped in the circuit by a … Continue reading

22. October 2012 by JackSparow
Categories: Hydraulic Circuits | Tags: , | Leave a comment

Hydraulic Closed Center System

In closed center system the hydraulic pump can rest when the oil is not required to operate a function. This circuit uses a control valve which is closed in the center to stop the oil flow from the pump. The … Continue reading

22. October 2012 by JackSparow
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Hydraulic Sliding Spool Valve

The figure above shows a hydraulic sliding-spool valve. The piston inside the valve slides back and forth to block and release ports in the housing. This valve sometimes called as a piston type spool valve, the sliding-spool valve has a … Continue reading

22. October 2012 by JackSparow
Categories: Directional Control Valves | Tags: , | Leave a comment

Hydraulic Flow Control Valves

A hydraulic flow control valve is a device used for adjusting or manipulating the hydraulic oil flow rate. The hydraulic flow control valve constructs of a flow passage or a port whose flow area can be varied. Most common applications … Continue reading

22. October 2012 by JackSparow
Categories: Flow Control Valves | Tags: , , , , | Leave a comment

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