Monthly Archives for June 2018

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

Synthetic Hydraulic Fluids

Synthetic fluids on the whole have excellent fire resistant properties. Many of these fluids may be used at high temperatures, and some are quite expensive. Such fluids are named after their base stocks, that is, the predominant material, and their … Continue reading

18. June 2018 by Dan
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Petroleum Base Fluids

Petroleum base oils are by far the most commonly used hydraulic fluid. Petroleum, a complex mixture of chiefly hydrocarbons, must be highly refined to produce a fluid with viscosity characteristics suitable for hydraulic control systems. Such mineral, turbine, or light … Continue reading

18. June 2018 by Dan
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Disadvantages of Hydraulic Control

Although hydraulic controls ofl’er many distinct advantages, several disadvantages tend to limit their use. Major disadvantages are thie following: 1. Hydraulic power is not so readily available as that of electrical powe:r This is not a serious threat to mobile … Continue reading

18. June 2018 by Dan
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Advantages of Hydraulic Control

There are many unique features of hydraulic control compared to other types of control. These are fundamental and account for the wide use of hydraulic control. Some of the advantages are the following: 1. Heat generated by internal losses is … Continue reading

18. June 2018 by Dan
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Fail-Safe Circuits

Fail-safe circuits are those designed to prevent injury to the operator or damage to the equipment. In general, they prevent the system from accidentally falling on an operator and also prevent overloading of the system. In following sections we shall … Continue reading

01. June 2018 by Dan
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Speed Control of a Hydraulic Motor

Figure 1.12 shows the speed control circuit of a hydraulic motor using a pressure-compensated FCV.The operation is as follows: – In a spring-centered position of the tandem four-way valve, the motor is hydraulically blocked. – When the valve is actuated … Continue reading

01. June 2018 by Dan
Categories: Hydraulic Circuits | Leave a comment

Meter-In Versus Meter-Out Flow-Control Valve Systems

A meter-out flow control system is one in which the FCV is placed in the outlet line of the hydraulic cylinder. Thus, a meter-out flow control system controls the oil flow rate out of the cylinder. Meter-in systems are used … Continue reading

01. June 2018 by Dan
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Speed Control of a Hydraulic Cylinder

The speed control of a hydraulic cylinder circuit can be done during the extension stroke using a flow-control valve (FCV). This is done on a meter-in circuit and meter-out circuit as shown in Fig. 1.11. Refer to Fig. 1.11(a). When … Continue reading

01. June 2018 by Dan
Categories: Hydraulic Circuits | Leave a comment

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