This type of circuit is used for constant load applications.įlow rate through flow control valves can vary if either the fluid pressure or the temperature changes. This type of circuit usually involves less heat generation because pressure on a pump equals the work resistance during a feed operation. The flow control valve regulates flow to a cylinder by diverting a portion of a pump flow to the tank. In this type of circuit flow control valve is not directly provided in the feed line but is connected to the pressure side as shown in Fig. A meter out speed control circuit is shown in Fig.
#DETAIL DESIGN OF CIRCUIT USED FOR SHAPER MACHINE PDF FREE#
A flow-control-and-check valve used in this circuit would allow reverse free flow. These circuits may also be used for overhauling load applications in which a workload tends to pull an operating piston faster than pump delivery,like in drilling, reaming, boring, turning machines. These types of circuit are best suited where work resistance is negative such as climb milling. A relief valve is kept a little above the operating pressure which is required by the type of application. In this type of circuit, a flow-control valve is installed on the return side of a cylinder so that it controls the cylinder actuation speed by metering its discharge flow.
A meter-in speed control is shown in Fig. A meter-in circuit is considered to be better in applications where a load always offers a positive resistance to flow during a controlled stroke.These circuits are used where slow feed rates are required. To conserve power and avoid undue stress on the pump, the relief valve pressure is kept little higher than the working pressure. Excess fluid returns to the tank through a relief valve.
Since this metering action involves reducing flow from a pump to the cylinder, the pump must deliver more fluid than is required to actuate the cylinder at the desired speed. Oilflowing into the work cylinder is metered through the flow-control valve. This flow-control valve is placed in pressure line that actuates the cylinder to work. This type of circuit consists of a pressure compensated flow control valve between the pump and cylinder. Depending upon the location of flow control valve for metering the oil, speed control circuits can be classified as meter-in, meter-out and bleed-off circuits. If the speeds of a number of loads are to controlled independently, the metering of the oil to individual cylinders is done by using flow control valves. Speed control of a single load can be done using variable displacement pump. Speed control required during different strokes can be done by regulating oil flow to the cylinder. In hydraulic operated machine tools and other mechanical equipment, speed control is required to enhance the functional versatility of the machine.
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