Hydraulic machines

Hydraulic machines

1. Hydraulic M achines Hydraulic machines use liquid fluid power to perform work. Heavy construction vehicles are a common example. In this type of machine, hydraulic fluid is pumped to various hydraulic motors and hydraulic cylinders throughout the machine and becomes pressurised according to the resistance present. The fluid is controlled directly or automatically by control valves and distributed through hoses, tubes, and/or pipes. Hydraulic systems, like pneumatic systems, are based on Pascal's law . which states that any pressure applied to a fluid inside a closed system will transmit that pressure equally everywhere and in all directions. A hydraulic system uses an incompressible liquid as its fluid, rather than a compressible gas.

2. Hydraulic M achinery Turbine is a device that extracts energy from a fluid (converts the energy held by the fluid to mechanical energy) Pumps are devices that add energy to the fluid (e.g. pumps, fans, blowers and compressors) TURBINES FLUID ENERGY MECH. WORK ELECTRICAL PUMPS ELECT. ENERGY FLUID ENERGY PRESS.HEAD

3. Tangential Flow Turbine : - In an impulse turbine, the flow takes place in tangential direction. Since the hydraulic energy of fluid is changed into kinetic energy of fluid, which is used in rotating the runner or rotor. Flow is tangential flow in this case. Pelton Turbine is one such example. Axial Flow Turbine:- An axial turbine is a turbine in which the flow of the working fluid is parallel to the shaft, as opposed to radial turbines, where the fluid runs around a shaft, as in a watermill. Example: Kaplan turbine and propeller turbine.

4. Radial flow turbines: - In this type of turbine the water strikes in the radial direction. ... Example: old Francis turbine. Outward flow turbine: The flow is outward from the centre to periphery (centrifugal type). Example: Fourneyron turbine. Definition of mixed-flow turbine :- An inward flow, reaction-type water turbine, in which the runner vanes are so shaped that they are acted on by the water pressure both axially and radially.

5. A xial flow pump :- An axial flow pump has a propeller-type of impeller running in a casing. The pressure in an axial flow pump is developed by the flow of liquid over the blades of impeller. It allows the fluid to enter the impeller axially and discharge the fluid nearly axially. The propeller of an axial flow pump is driven by a motor. M ixed flow pump :- A mixed flow pump is a centrifugal pump with a mixed flow impeller. ... For this reason, mixed flow pumps with higher specific speeds are usually designed with an axial tubular casing and an "onion type" or axial flow diffuser through which the fluid flows towards the discharge elbow and the pump discharge nozzle.

6. Radial flow centrifugal pump:- Radial flow pumps are centrifugal pumps in which the fluid is pumped perpendicularly to the pump shaft. The flow mechanism in a centrifugal pump can generally be described as follows: Through a suction flange the liquid flows through the suction hub into the rotating impeller due to an energy fall. The pump unit absorbs mechanical energy from a drive motor through a shaft. The blades of the impeller which is permanently fixed on the shaft exert a force on the fluid and increase its angular moment. Pressure and absolute speed increase as a result.

7. What is a Reciprocating Pump? Reciprocating pump is a positive displacement pump where certain volume of liquid is collected in enclosed volume and is discharged using pressure to the required application. Reciprocating pumps are more suitable for low volumes of flow at high pressures. A Reciprocating Positive Displacement pump works by the repeated back-and-forth movement (strokes) of either a piston, plunger or diaphragm

8. Rotary positive displacement pumps :- Rotary positive displacement pumps use the actions of rotating cogs or gears to transfer fluids, rather than the backwards and forwards motion of reciprocating pumps. The rotating element develops a liquid seal with the pump casing and creates suction at the pump inlet. Fluid, drawn into the pump, is enclosed within the teeth of its rotating cogs or gears and transferred to the discharge. The simplest example of a rotary positive displacement pump is the gear pump. There are two basic designs of gear pump: external and internal