Gear Pump Design Pdf

Bushing - Carbon graphite, bronze, silicon carbide, tungsten carbide, ceramic, colomony, and other specials materials as needed. With four bearings in the liquid and tight tolerances, they are not well suited to handling abrasive or extreme high temperature applications.

Increasing the gap diminishes the pumps ability to hold a pressure difference between the inlet and outlet. This can also result in the tight tolerances being lost if the gear teeth effectively become chewed up, resulting in backwards flow and lost efficiency.

How A Gear Pump Works

External Gear Pumps

Thought about a screw pump? The pump head is now nearly flooded, just prior to forcing the liquid out of the discharge port. Tighter internal clearances provide for a more reliable measure of liquid passing through a pump and for greater flow control. Have you considered a screw pump as an alternative? By precisely matching the materials of construction with the liquid, superior life cycle performance will result.

External gear pumps are usually available with either spur gears, making them too bi-directional, or herringbone gears, which are for particularly viscous fluids but do not allow reversible flow. Manufacturers Viking Pump Inc. Bi-directional if spur gears are selected. Gear pump working principle Gear pumps are one of the most common types of positive displacement pump.

Internal Gear PumpsGear pump design pdf

Disadvantages Usually requires moderate speeds Medium pressure limitations One bearing runs in the product pumped Overhung load on shaft bearing. This ensures a reliable, steady output of fluid passes through which is required for accurate metering. View our screw pump range. This gap must be small in order to maintain the pressure increase across the pump. Can handle high temperature fluids.

This is not easily quantified theoretically and is often determined experimentally. Intermeshing gears of the idler and rotor form locked pockets for the liquid which assures volume control. External gear pumps in particular can be engineered to handle even the most aggressive corrosive liquids.

Small external gear pumps usually operate at or rpm and larger models operate at speeds up to rpm. Each gear is supported by a shaft with bearings on both sides of the gear. The tight internal clearances between the gear teeth and the pump casing allow very precise volumes of fluid to pass for each gear revolution. This is due to the single point of end clearance the distance between the ends of the rotor gear teeth and the head of the pump.

As the following list indicates, rotary pumps can be constructed in a wide variety of materials. Internal gear pumps are exceptionally versatile. How Internal Gear Pumps Work.

Call Us sales castlepumps. Because of this, external gear pumps are popular for precise transfer and metering applications involving polymers, fuels, and chemical additives. This can cause reduced flow and efficiency.

While they are often used on thin liquids such as solvents and fuel oil, they excel at efficiently pumping thick liquids such as asphalt, chocolate, and adhesives. Internal gear pumps are able to handle high temperature fluids such as thermal oil, and can be supplied with an external jacket to maintain the temperature level. In addition to imposing limits on the operational speed, in many cases, the bearings determine the maximum pressure the pump can operate at. This clearance is adjustable to accommodate high temperature, maximize efficiency for handling high viscosity liquids, and to accommodate for wear.

Castle Pumps

Because internal gear pumps have only two moving parts, they are reliable, simple to operate, c .net interview questions with answers pdf and easy to maintain. The heat caused by this friction will cause the gears to expand and begin wearing against the pump casing resulting in damage to the internals. Liquid enters the suction port between the rotor large exterior gear and idler small interior gear teeth.

External Gear Pump Overview. Bi-directional - Internal gear pumps have spur gears, which enable flow in either direction.

This is a function of the fluid viscosity, clearance between internal components, friction between mating components, and other variables. These pumps have few moving parts, making them inexpensive. Two identical gears positioned side by side, rotating into one another.

Convert mechanical power into fluid power. These need to be regularly checked for wear as they are what maintain the balance of the gears. Because the gears are supported on both sides, external gear pumps are quiet-running and are routinely used for high-pressure applications such as hydraulic applications. Gear pumps are one of the most common types of positive displacement pump. Rotor and idler teeth mesh completely to form a seal equidistant from the discharge and suction ports.

Finally, the meshing of the gears forces liquid through the outlet port under pressure. External gear pumps are similar in pumping action to internal gear pumps in that two gears come into and out of mesh to produce flow. One gear is driven by the motor and in turn moves the other gear. Liquid flows into the cavity and is trapped by the gear teeth as they rotate.

Smaller outlet sizes and higher capacities. External gear pumps have close tolerances and shaft support on both sides of the gears. Works to moderate pressures. They're also bi-rotational, meaning that the same pump can be used to load and unload vessels. The internal gear pump is non-pulsing, self-priming, and can run dry for short periods.

The arrows indicate the direction of the pump and liquid. This power will be denoted at P loss. If solids make it into the tight clearances between the gears they can result in immediate wear and a reduced pump lifespan. How External Gear Pumps Work. Whilst suitable for relatively thick oils, they are typically only suited to clean, non-abrasive liquids that are free of solids due to the meshing gears.

As the gears come out of mesh, they create expanding volume on the inlet side of the pump. This seal forces the liquid out of the discharge port. Therefore to get the best from their output they need to be operated as close to their maximum rated speeds as they can.