Muhammad Mubashir Ghori

In a radial piston pump, the pistons are arranged like wheel spokes in a short cylindrical block. A drive shaft, which is inside a circular housing, rotates a cylinder block. The block turns on a stationary pintle that contains the inlet and outlet ports. As a cylinder block turns, centrifugal force slings the pistons, which follow a circular housing. A housing’s centerline is offset from a cylinder block’s centerline. The amount of eccentricity between the two determines a piston stroke and, therefore, a pump’s displacement. Controls can be applied to change a housing’s location and thereby vary a pump’s delivery from zero to maximum. Figure shows a ninepiston, radial piston pump. When a pump has an uneven number of pistons, no more than one piston is completely blocked by a pintle at one time, which reduces flow pulsations. With an even number of pistons spaced around a cylinder block, two pistons could be blocked by a pintle at the same time. If this happens, three pistons ...

In a vane-type pump, a slotted rotor splined to a drive shaft rotates between closely fitted side plates that are inside of an elliptical- or circular-shaped ring. Polished, hardened vanes slide in and out of the rotor slots and follow the ring contour by centrifugal force. Pumping chambers are formed between succeeding vanes, carrying oil from the inlet to the outlet. A partial vacuum is created at the inlet as the space between vanes increases. The oil is squeezed out at the outlet as the pumping chamber’s size decreases. Because the normal wear points in a vane pump are the vane tips and a ring’s surface, the vanes and ring are specially hardened and ground. A vane pump is the only design that has automatic wear compensation built in. As wear occurs, the vanes simply slide farther out of the rotor slots and continue to follow a ring’s contour. Thus efficiency remains high throughout the life of the pump. 

Figure shows a lobe pump. It differs from other gear pumps because it uses lobed elements instead of gears. The element drive also differs in a lobe pump. In a gear pump, one gear drives the other. In a lobe pump, both elements are driven through suitable external gearing.

Figure shows an internal gear pump. The teeth of one gear project outward, while the teeth of the other gear project inward toward the center of the pump. One gear wheel stands inside the other. This type of gear can rotate, or be rotated by, a suitably constructed companion gear. An external gear is directly attached to the drive shaft of a pump and is placed off-center in relation to an internal gear. The two gears mesh on one side of a pump chamber, between an inlet and the discharge. On the opposite side of the chamber, a crescentshaped form stands in the space between the two gears to provide a close tolerance. The rotation of the internal gear by a shaft causes the external gear to rotate, since the two are in mesh. Everything in the chamber rotates except the crescent, causing a liquid to be trapped in the gear spaces as they pass the crescent. Liquid is carried from an inlet to the discharge, where it is forced out of a pump by the gears meshing. As liquid is carried away f...

Figure shows the operating principle of an external gear pump. It consists of a driving gear and a driven gear enclosed in a closely fitted housing. The gears rotate in opposite directions and mesh at a point in the housing between the inlet and outlet ports. Both sets of teeth project outward from the center of the gears. As the teeth of the two gears separate, a partial vacuum forms and draws liquid through an inlet port into chamber A. Liquid in chamber A is trapped between the teeth of the two gears and the housing so that it is carried through two separate paths around to chamber B. As the teeth again mesh, they produce a force that drives a liquid through an outlet port.

This pump generally is used where a large volume of flow is required at relatively low pressures. It can be connected in series by feeding an outlet of one pump into an inlet of another. With this arrangement, the pumps can develop flow against high pressures. A centrifugal pump is a nonpositive-displacement pump, and the two most common types are the volute and the diffuser. The centrifugal pump is the most used pump type in the world. The principle is simple, well-described and thoroughly tested, and the pump is robust, effective and relatively inexpensive to produce. There is a wide range of variations based on the principle of the centrifugal pump and consisting of the same basic hydraulic parts. The majority of pumps produced by Grundfos are centrifugal pumps. Principle of the centrifugal pump An increase in the fluid pressure from the pump inlet to its outlet is created when the pump is in operation. This pressure diff...

Flow rate is the amount of time something takes to flow down a (funnel, of inclined plane) In   physics   and   engineering , in particular   fluid dynamics   and   hydrometry , the   volumetric flow rate, (also known as   volume flow rate,   rate of fluid flow   or   volume velocity) is the volume of fluid which passes per unit time; usually represented by the symbol   Q. The SI unit   is m 3 /s ( cubic meters per second ). Another unit used is sccm (standard cubic centimeters per minute). In   US Customary Units   and   British Imperial Units , volumetric flow rate is often expressed as ft 3 /s ( cubic feet   per second) or   gallons per minute   (either U.S. or imperial definitions). Volumetric flow rate should not be confused with   ...

The pressure (force over area) exerted by the fluid on the bottom of the reservoirs as a result of its gravitational force is identical in the two vessels. The hydrostatics pressure depends only on the height 1 of the liquid column and not on the shape of the vessel. Hydraulic Pressure Intensifier: The hydraulic press is force intensifiers, the inverse system being a pressure intensifiers.  Two pistons of different surface are connected by a rod. If pressure Pe is exerted on piston  area, forces acts upon the large piston. This force is transmitted to the small piston by the piston rod and acts on the smaller piston area. Thus pe2 is large than pe1. Neglecting friction losses, the following equation applies: F 1 = F 2 Pe1 x A 1 = pe2 x A 2 Pe1/pe2 = A 2 /A 1 In a pressure intensifiers, the pressures are inversely proportional to the areas.

Hydraulics is the science of transmitting force and/or motion through the medium of a confined liquid. In a hydraulic device, power is transmitted by pushing on a confined liquid. Figure 1-1 shows a simple hydraulic device. The transfer of energy takes place because a quantity of liquid is subject to pressure. To operate liquid-powered systems, the operator should have a knowledge of the basic nature of liquids. This chapter covers the properties of liquids and how they act under different conditions.

Hydraulic Motor: \ displacement: 5 cm /r (0.30 in³/r) continuous speed 8500 rpm continuous power 13kW (17.5 hp) length 134mm (5.28 in) weight 5 kg (11 lb) Electric Motor: speed 2900 rpm  power 11kW (15 hp) length 320mm (12.6 in) weight 65 kg (145 lb)

Types of Hydraulic Fluids To assure proper system operation and to avoid damage to nonmetallic components of the hydraulic system, the correct fluid must be used. When adding fluid to a system, use the type specified in the aircraft manufacturer’s maintenance manual or on the instruction plate affixed to the reservoir or unit being serviced. The three principal categories of hydraulic fluids are: Minerals Polyalphaolefins Phosphate esters When servicing a hydraulic system, the technician must be certain to use the correct category of replacement fluid. Hydraulic fluids are not necessarily compatible. For example, contamination of the fire-resistant fluid MIL-H-83282 with MIL-H-5606 may render the MIL-H-83282 non fire-resistant. Mineral-Based Fluids  Mineral oil-based hydraulic fluid (MIL-H-5606) is the oldest, dating back to the 1940s. It is used in many systems, especially where the fire hazard is comparatively low. MIL-H-6083 is simply a rust-inhibited version...

Hydraulic Fluid Hydraulic system liquids are used primarily to transmit and distribute forces to various units to be actuated. Liquids are able to do this because they are almost in-compressible. Pascal’s Law states that pressure applied to any part of a confined liquid is transmitted with undiminished intensity to every other part. Thus, if a number of passages exist in a system, pressure can be distributed through all of them by means of the liquid. Manufacturers of hydraulic devices usually specify the type of liquid best suited for use with their equipment in view of the working conditions, the service required, temperatures expected inside and outside the systems, pressures the liquid must withstand, the possibilities of corrosion, and other conditions that must be considered. If in-compressibility and fluidity were the only qualities required, any liquid that is not too thick could be used in a hydraulic system. But a satisfactory liquid for a particular installation mu...

Pioneers, such as Galileo, Newton and Pascal, discovered interesting phenomena many years in advance of actual practical applications of their theories. Pascal discovered and formulated the “Law of Hydraulics” about the year  1650, but nearly 150 years passed before that law was exploited in a practical application. Pascal’s law, which states “an external force exerted on a unit of area of a confined liquid will be transmitted undiminished to every unit area of the interior of the vessel” , is the basis upon which every hydraulic device functions.

Pascal’s Law,  which states: “an external force exerted on a unit of area of a confined liquid will be transmitted undiminished to every unit area of the interior of the vessel”