A hydraulic pump is a mechanical device that converts mechanical power into Ii ydraulic energy It generates flow with enough power to overcome pressure induced by the load When a hydraulic pump operates, it performs two functions. First its mechanical action creates a vacuum at the pump inlet which allows atmospheric pressure to force liquid from the reservoir into the inlet line to the pump Second, its mechanical action delivers this liquid to the pump outlet and forces it into the hydraulic system.
A pump produces liquid movement or flow. it does not generate pressure It produces the flownecessaryfor the development of pressure which is a function of resistance to fluid flow in the system. For example. the pressure of the fluid at the pump outlet is zero for a pump not connected to a system (load). Further, for a pump delivering into a system, the pressure will rise only to the level necessary to overcome the resistance of the load. |
| OPERATION |
A pump must have a continuous supply of fluid available to the inlet port to supply fluid to the system. As the pump forces fluid through the outlet port, a partial vacuum or low-pressure area is created at the inlet port. When the pressure at the inlet potful the pump is lower than the local atmospheric pressure, atmospheric pressure acting on the fluid in the reservoir forces the fluid into the pump's inlet the pump is located at a level lower than the reservoir, the force of gravity supplements atmospheric pressure on the reservoir. |
| PERFORMANCE |
Pumps are normally rated by their volumetric output and pressure Voleinetric output is the amount of fluid a pump can deliver to its outlet port in a certain period of time at a given speed. Volumetric output is usually expressed in liters per minute (lit/m). Since changes inn pumps affect volumetric output, some pumps are rated by their displacement. Pump displacement is the amount. of fluid the pump can deliver per cycle. Since most pumps are a rotary drive. displacement is usually expressed in terms of cubic cm. per revolution As stated earlier, the pump does not create pressure However. the pressure developed by the restrictions in the system is a factor that affects the volumetric output of the pump As the system pressure increases. the volumetric output decreases
This drop in volumetric output is the result of an increase in Me amount of internal leakage from the outlet side to the inlet side of the pump This leakage is referred to as pump slippage and is a factor that must be considered in all pumps This explains why most pumps are rated in terms of Volumetric output at a given pressure
Classification of pumps
All pumps maybe classified as either positive- displacement or non-positive-displacement. Most pumps used in hydraulic systems are positive-displacement
A non-posdive-displacement pump produces a continuous flow. However, because it does not provide a positive internal seal against |
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High quality of gears to minimizes leakage across gear tips, high precise geometrical tolerance of body and bearing blocks with seals for high volumetric efficiency and specially designed thurst bearing / bush gives low noise, Du-lined/bi-metal bearings for jerkless operation and working against High mechanical Loads operating up to 200 bar and up to 3000 rpm.
Low pressure bearing lubrication is feature of all COLT GEAR PUMPS, this is achieved by utilising the action generated when the gear teeth separate to draw lubricating fluid from the inlet port and along each bearing journal by way of passage in the composite bush.This proven system ensures efficient cooling and lubrication of the bearing with a constant supply of fluid independent of operating condition. |
