Applied Product Catalog 2017 2018 Page i46 Technical Reference

i46 Call your local Applied service center to order at 1-866-351-3464 or visit us online at DIRECTIONAL VALVE - A valve which selectively directs fluid to or prevents fluid from desired channels. DISPLACEMENT - The quantity of fluid which can pass through a pump, motor or cylinder in a single revolution or stroke. DOUBLE ACTING CYLINDER - A cylinder in which fluid force can be applied in either direction. DRAIN - A passage in, or a line from, a hydraulic component which returns leakage fluid independently to a reservoir or to a vented manifold. EFFICIENCY - The ratio of output to input. Volumetric efficiency of a pump is the actual output flow divided by the theoretical or design flow. The overall efficiency of a hydraulic system is the output power divided by the input power. Efficiency is usually expressed as a percent. ELECTRO-HYDRAULIC SERVO VALVE - A directional type valve which receives a variable or controlled electrical signal and which controls or meters hydraulic flow. EMULSION - A fluid formed by the suspension of one liquid in another. ENERGY - The ability or capacity to do work. Measured in units of work. FEEDBACK (or feedback signal) - The output signal from a feedback element. FILTER - A device whose primary function is the retention of insoluble contaminants from a fluid by a porous media. FLOODED - A condition where the pump inlet is charged by placing the reservoir oil level above the pump inlet port. FLOW CONTROL VALVE - A valve which controls the rate of oil flow. FLOW RATE - The volume, mass or weight of a fluid passing through a conductor per unit of time. Normally expressed in gallons per minute (gpm). FLUID - A liquid or gas. A liquid that is specially compounded for use as a power transmitting medium in a hydraulic system. FORCE - Any push or pull measured in units of weight. In hydraulics, total force is expressed by the product of pressure and the area of the surface on which the pressure acts. F = P x A. FOUR-WAY VALVE - A directional valve having four flow paths. FREQUENCY - The number of times an action occurs in a unit of time. Frequency is the basis of all sound. A pump or motor's basic frequency is equal to its speed in revolutions per second multiplied by the number of pumping chambers. FRONT CONNECTED - A condition wherein piping connections are on normally exposed surfaces of hydraulic components. FULL FLOW - In a filter, the condition where all the fluid must pass through the filter element. GAUGE PRESSURE (psig) - A pressure scale which ignores atmospheric pressure. Its zero point is atmospheric pressure (14.7 psia at sea level). gph (gallons per hour) - Unit of measure representing volume of liquid flow. gpm (gallons per minute) - Unit of measure representing volume of liquid flow. HEAD - The height of a column of fluid above a given point expressed in linear units. Head is often used to indicate gauge pressure. The pressure is equal to the height times the density of the fluid. HEAT - The form of energy that has the capacity to create warmth or to increase the temperature of a substance. Any energy that is wasted or used to overcome friction is converted to heat. Heat is measured in calories or British Thermal Units (BTUs). One BTU is the amount of heat required to raise one pound of water one degree Fahrenheit. HEAT EXCHANGER - A device which transfers heat through a conducting wall from one fluid to another. HORSEPOWER (hp) - The power required to lift 550 pounds one foot in one second or 33,000 pounds one foot in one minute. A horsepower is equal to 746 watts or to 2544 BTUs per hour. HYDRAULIC BALANCE - A condition of equal opposed hydraulic forces acting on a part in a hydraulic component. HYDRAULIC CONTROL - A control which is actuated by hydraulically induced forces. HYDRAULICS - Engineering science pertaining to liquid pressure and flow. HYDRO - Greek word for water. HYDRODYNAMICS - Engineering science pertaining to the energy of liquid pressure and flow. HYDROSTATICS - Engineering science pertaining to the energy of liquids at rest. INTENSIFIER - A device which converts low pressure fluid power to higher pressure fluid power. JIC - Joint Industry Conference. 37 JIC - Refers to a JIC standard that establishes the 37 flare for use in plumbing with steel tubing. A 45 flare is commonly used for copper tube. This distinction assists in preventing the accidental use of low pressure fittings, designed for use with copper tubing, in hydraulic systems where pressures merit steel tubing and appropriate fittings. KINETIC ENERGY - Energy that a substance or body has by virtue of its mass (weight) and velocity. LAMINAR (flow) - A condition where the fluid particles move in continuous parallel paths. Streamline flow. LEVERAGE - A gain in output force over input force by sacrificing the distance moved. Mechanical advantage or force multiplication. LIFT - The height a body or column of fluid is raised; for instance, from the reservoir to the pump inlet. Lift is sometimes used to express a negative pressure or vacuum. The opposite of head. LINE - A tube, pipe or hose which acts as a conductor of hydraulic fluid. LINEAR ACTUATOR - A device for converting fluid power into linear motion. A piston or ram. LOAD SENSING - A type of hydraulic circuit where the actual pressure required by the load is transmitted to the control elements such as valves and pumps. This typically allows the system to deliver only the pressure and flow required, usually saving energy. MANIFOLD - A fluid conductor which provides multiple connection ports. Fluid Power Glossary

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