Monthly Archives for May 2019

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
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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
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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
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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