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Double-Pump Hydraulic System

Figure 1.5 shows an application for an unloading valve. It is a circuit that uses a high-pressure, low-flow pump in conjunction with a low-pressure, high-flow pump. A typical application is a sheet metal punch press in which the hydraulic cylinder … Continue reading

14. May 2019 by Dan
Categories: Hydraulic Circuits | Leave a comment

Regenerative Cylinder Circuit

Figure 1.3 shows a regenerative circuit that is used to speed up the extending speed of a double-acting cylinder. The pipelines to both ends of the hydraulic cylinder are connected in parallel and one of the ports of the 4/3 … Continue reading

13. May 2019 by Dan
Categories: Hydraulic Circuits | Leave a comment

Pump-Unloading Circuit

Figure 1.4 shows a hydraulic circuit to unload a pump using an unloading valve.When the cylinder reaches the end of its extension stroke, the pressure of oil rises because the check valve keeps the high-pressure oil. Due to high-pressure oil … Continue reading

12. May 2019 by Dan
Categories: Hydraulic Circuits | 1 comment

Control of a Double-Acting Hydraulic Cylinder

The circuit diagram to control double-acting cylinder is shown in Fig. 1.2. The control of a double-acting hydraulic cylinder is described as follows: 1. When the 4/3 valve is in its neutral position (tandem design), the cylinder is hydraulically locked … Continue reading

12. May 2019 by Dan
Categories: Hydraulic Circuits | Leave a comment

Simple Pressure-Relief Valve

The most widely used type of pressure control valve is the pressure-relief valve because it is found in practically every hydraulic system. Schematic diagram of simple relief valve is shown in Fig. 1.1 and three-dimensional view is shown in Fig. … Continue reading

10. May 2019 by Dan
Categories: Pressure Control Valves | Leave a comment

Telescopic Cylinder

A telescopic cylinder (shown in Fig. 1.6) is used when a long stroke length and a short retracted length are required. The telescopic cylinder extends in stages, each stage consisting of a sleeve that fits inside the previous stage. One … Continue reading

09. May 2019 by Dan
Categories: Actuators | Leave a comment

Double-Acting Cylinder with a Piston Rod on One Side

Figure 1.4 shows the operation of a double-acting cylinder with a piston rod on one side. To extend the cylinder, the pump flow is sent to the blank-end port as in Fig. 1.4(a). The fluid from the rod-end port returns … Continue reading

09. May 2019 by Dan
Categories: Actuators | Leave a comment

Unloading Valves

Unloading valves are pressure-control devices that are used to dump excess fluid to the tank at little or no pressure. A common application is in high-low pump circuits where two pumps move an actuator at a high speed and low … Continue reading

08. May 2019 by Dan
Categories: Pressure Control Valves | Leave a comment

Flow Trough Orifice

Orifices are a basic means for the control of fluid power. Flow characteristics of orifices plays a major role in the design of many hydraulic control devices. An orifice is a sudden restriction of short length (ideally zero length for … Continue reading

18. June 2018 by Dan
Categories: Hydraulic Control System | Leave a comment

Selection of Hydraulic Fluid

Many petroleum and synthetic fluids are available and more are being formulated. The highly technical formulations of the fluids with their various pros and cons makes the selection of such fluids difficult for those who are not thoroughly acquainted with … Continue reading

18. June 2018 by Dan
Categories: Hydraulic Fluid | Leave a comment

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