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What is a gerotor oil pump


A Gerotor oil pump is a type of positive displacement pump consisting of an external gerotor, an internal gerotor and a housing.

As you can see in the illustration below, the outer gerotor has one more tooth than the inner gerotor and has a convex cycloidal profile on its outer surface. The inner gerotor has a concave cycloidal profile on its inner surface and is installed off-center within the outer gerotor. Both gerotors are positioned such that the convex and concave surfaces are in contact with each other. Housings, usually made of cast iron or aluminum, provide the rotors and necessary supports.

How various types of gerotor oil pump work

we talked about centrifugal pumps and reciprocating pumps but it’s not over yet pumps are such a wide and evolving topic that a person can keep on talking and never stop so in today’s video we’ll be talking about another type of pump called the rotary pump rotary pumps are positive displacement gerotor oil pump that use rotary motion instead of reciprocating motion in their pumping action the rotary pumps can be designed to pump liquid gases and even mixtures of the two unlike reciprocating pumps the rotary pumps.

Rotary Pumps:

Since the fluid flow is continuous they develop a dynamic seal or rotary pumps have three major operations unlike the two of the reciprocating pumps the first operation is the suction operation here the fluid is sucked into the pump from the pipe or reservoir the next operation is the travel operation here the fluid moves from the suction side gerotor oil pump to the exit side the third operation

Inner gear pump working principle

The exhaust operation here the fluid exits the pump and flows into the exit pipe if you feel all this a bit confusing don’t worry as we progress in the video you’ll be able to get a better understanding ever since the development of better drivers for centrifugal pumps they have been continuously replacing all the type of the pumps

Gear Pumps:

There is one huge disadvantage for these pumps similar to how kryptonite is dangerous for Superman so as high viscosity fluids for centrifugal pumps this is because it is very difficult to pump these fluids with just the centrifugal action due to this a different type of pump called gear pumps are used high viscosity fluids are the bread and butter of gear pumps gerotor oil pump consist of two gears meshing

Each other one gear is driven by an external shaft this is called the drive of gear the other gear acts as an idle gear and rotates with the help of the meshing action from the drive of gear the gear pumps normally have extremely close tolerance between the gear teeth and the wall of the pump case

Close Tolerance:

The close tolerance is the main reason behind the pumping action as the gears of the pump rotate they get separated at the suction side of the gerotor oil pump this area is generally filled with fluid even if the suction area is not filled the gear pumps are self priming this means they are capable of generating sufficient suction pressure to pull the it towards the gears for pumping this is the end of the suction operation as the gears rotate the fluid is carried by the gears towards

The discharge side of the pump the type meshing and almost zero clearance ensures that the fluid doesn’t leak this concludes the travel operation as the gear is now Re-mesh together the total volume will reduce this forces the fluid out of the pump through the discharge pipe this ends the discharge operation

Types of Gerotor oil pump

There are many variations and types of gear pumps the variations are made to accommodate the different types of fluid that they will be used pump the first type is the

External gear pump

This is the type of gear we discussed until now the next type of gear pump is called the internal gear pump there are two different variants of internal gerotor oil pumps one is the gear outer and the other is a crescent gear pump the gear rotor is a type of gear pump which has two gears arranged one within another the working of the pump is similar to the external gear pumps the fluid enters the gear water through an inlet port

Inner working prnciple of External gear oil pump

The fluid is then transported to the discharge port by the internal gear once the fluid is at the discharge side the area between the two rotors decreases due to its shape this forces the liquid out through the discharge port the gear water pumps are most commonly used in automobiles to pump lubricant or oil this is because these gerotor oil pump are smaller than external gear pumps and are also able to pump viscous fluids efficiently.

External gear pump

The next type of external gear pump is the crescent gear pump just like the previous two types of gear pumps the crescent gear also has two gears which meshed together the external gear is larger and has more teeth than the internal gear however it gets the name Crescent due to the crescent or moon shaped wall that is present inside the gerotor oil pump

when the teeth of the two gears come out of mesh low-pressure zones are created at the gaps between the teeth fluid is trapped between the teeth of the gears and the walls of the pump as the fluid travels with the gear it reaches a point where the gear starts to mesh again this force is the fluid out of the gerotor oil pump and it exits through the discharge pipe

Crescent Gear Pumps Uses

The Crescent pumps are able to pump fluid with much higher viscosity than give outer gerotor oil pump these pumps are most commonly used in oil refineries to pump oil into the holding tanks the pumps are also used in automatic transmission of cars to pump transmission fluid gear are not without disadvantages increasing the RPM of the pumps higher than the prescribed value for a fluid can lead to cavitation the pumps also have issues when pumping volatile liquids

Gerotor pump

The gerotor oil pump is a rotary positive displacement gerotor oil pump that moves fluid using the rotary motion of the pumping elements. gerotor oil pump are similar in operation to traditional internal gear pumps but swap the position of the drive and driven gears and do not use a crescent to create the gear offset. Liquid enters the suction port between the teeth of the elements.

There may be a smaller, internal, motive force detail…and a bigger, outer, pushed detail. At the same time as tooth counts vary, the outer element has one more tooth than the internal detail, developing cavities between the teeth. Because the pump rotates, these cavities extend at the inlet aspect and settlement on the opening aspect.

As the tooth pop out of mesh, a low-pressure area is created on the suction port, pulling liquid into the spaces. The liquid continues to travel via the gerotor oil pump, between the tooth of the tools-within-a-gear principle. Liquid is averted from returning to the suction side because of the close tolerance of the gears, appearing as a seal between the suction and discharge ports.

When the teeth mesh completely, liquid is forced out of the spaces and out of the discharge port. The gerotor oil pump is efficient, compact, and quiet. The easy design, with few shifting components, is good for a wide kind of applications which include warm cooking oil filtration and automobile packages like fuels, lube oils, and transmission fluids.

Rotary Lobe Pump

One of the most common pump types in the food and pharmaceutical industry is the rotary load pump line of hygienic pumps by right flow technologies includes load pumps with model sizes and designs to cover a wide range of pumping applications and hygienic requirements load pumps are similar in pumping action to external gear pumps but differ in that the rotors are driven independently on two rotating shafts a pair of external timing gears ensure.

lobe pump working principle

That the rotors do not contact as the rotors turn a cavity is formed at the inlet side of the pump this creates a vacuum to pull the liquid into the spaces between the tips of the lobes this liquid is trapped between these lobes.

The close-fitting casing wall the rotation of the rotors includes the liquid around to the hole facet of the pump the liquid does now not skip between the rotors on the outlet the meshing of the lobes forces the liquid through the outlet port because of the large pumping cavities and non-contacting design these pumps are ideal for the gentle handling of both thin and viscous liquids and liquids containing large solids they are designed to be easily cleaned making them ideal for applications requiring sanitary construction and frequent cleaning.

The van pump

Vane pumps are available in several vane configurations including sliding vane, flexible vane, oscillating vane, rolling vane and external vane, with each type offering unique benefits.

Most vane pumps work from the same general principle.

  1. The slotted rotor is centrally supported on an eccentric cam. The rotor is close to the cam wall, creating a crescent-shaped cavity. The rotor is sealed to the cam by two side plates. The vane or blade fits into the slot of the propeller. As the impeller rotates and fluid enters the pump, centrifugal force, hydraulic pressure, and/or pushrods push the vanes toward the housing wall.
  2. A tight seal between the vanes, rotors, cams and side plates is the key to the typical good suction characteristics of vane pump principles.
  3. As the cycle continues, the volume of the cavity increases, pumping fluid through the cam holes into the chamber.
  4. As the rotor rotates, the vanes carry the fluid to the opposite side of the crescent where, as the volume of the cavity decreases, it discharges through the discharge holes of the cam. The The fluid then exits the discharge port.
  5. Vane pumps can handle fluids of moderate viscosity, with engineered non-metallic vane materials these pumps are suitable for low viscosity, non-lubricating fluids such as LP gas, ammonia, solvents, alcohol, fuel oil, gasoline and coolants.

Because it has no internal metal-to-metal contact and provides automatic compensation for wear and tear, it can maintain peak performance when pumping non-lubricating fluids. Although it can be used with viscosities up to about 10,000 centipoise, performance degrades rapidly as viscosity increases above 200 centipoise.

These pumps are known for their superior drying capacity, ease of maintenance and good suction properties. They typically handle fluid temperatures from -32°C to 260°C and differential pressures up to 15 bar (higher than hydraulic vane pumps).

Screw pump

Screw pumps use one or more screws that rotate either clockwise or counterclockwise around an axis to move fluids of higher or lower viscosity along the axis. The threads of each screw move a certain amount of fluid with each rotation to the center of the pumps inside the housing, where it is then discharged.

These pumps evolved from the Archimedes screw, which was invented in Greece in the 3rd century BC to move water for irrigation through a screw that fit into a cylinder with minimal clearance. Today, most screw faucets use at least two screws.

There are several types of screw pumps, two of the most common of which are the twin or twin screw pumps, where there is a set of lubricated timing gears outside the pump chamber. There is no direct contact between the screws; and triple-screw pumps, where the driving screw combines with two other screws to create pressure—the screws are in contact with each other, and this type is limited to handling pure liquids.

These pumps can deliver higher flow rates than other types of positive displacement pumps and have a wide variety of applications as water and lift hydraulic pumps for crude oil, bitumen and lubricating oils, vegetable oils and hydrocarbons.

Low Pumps Uses

This is because volatile liquids tend to vaporize locally as gear teeth spaces expand to address this issue a different kind of pump is used low pumps are similar to the external gear pumps in the way they work similar to how we have two gears which rotate and gerotor oil pump the fluid low pumps have two lobes the two lobes rotate in opposite directions to pump the fluid when the two lobes of the pumps come out of the mesh they increase the volume at the inlet side this forces

The fluid into the pump as the loops continue rotation they carry the fuel towards the outlet side finally when the lobes of the pump Re-mesh again the fluid is pumped into the exit port unlike the gear pumps the lobes do not make contact with each other since there is no metal to metal contact the abrasive wear is very less this increases the life of the pumps the load pumps are most commonly used in the for industry to pump semi-solids.

They can handle semi solids without degrading the product the Lowe pumps are used to pump low-viscosity fluids with diminished performance the loss in performance is mainly due to the fact that the lobes are not in contact .

Advantages of Gerotor oil pump 

High efficiency: gerotor oil pump offer high efficiency, which means they can move large volumes of fluid per revolution. Their volumetric efficiency is up to 98%, making them one of the most efficient types of displacement pumps.
Low Noise and Vibration: gerotor oil pump operate with low noise and vibration levels, making them ideal for applications that require quiet operation. They produce less noise and vibration than other types of pumps such as gear or vane pumps.

Disadvantages of Gerotor oil pump

Like any type of pump, it has its drawbacks. The main disadvantages of gerotor pumps are:

Limited Viscosity Range: gerotor oil pump have a limited viscosity range that they can pump efficiently.  They are not suitable for pumping highly viscous liquids like jaggery or honey.
Limited suction capacity: gerotor oil pump have limited suction capacity, which means they cannot draw liquid from a deep source or from a high elevation. They require a positive fluid to function efficiently.
Wear and tear: Due to the close tolerances between the rotors and the housing, gerotor oil pump can wear and tear over time. This can lead to reduced performance and increased maintenance costs.

Readmore >>>>>> What is the working pressure of a gear pump

Applications of Gerotor oil pump

Gerotors are used in a variety of industrial and automotive applications, particularly in hydraulic systems that require precise and efficient fluid flow. They are also useful in other non-industrial applications such as power steering systems for vehicles due to their lower noise level than high-speed rotary pumps (which can be noisy when running machinery near people.

Other common applications of Gerotor oil pump include:

1. Engine oil pipes and fuel pipes in automobiles and other internal combustion engines
2. Lubrication systems in compressors, gearboxes and other industrial machinery
3. Hydraulic lifts and elevators in industrial and commercial buildings
4. High pressure hydraulic systems in aerospace and defense applications
5. Vacuum tubes and blowers in a wide range of industries
6. Positive displacement compressor for gases and other pressurized liquids
7. Hydraulic motor for driving conveyor belts, mixers and other industrial machinery
8. Coolant pump for engines and other heat generating equipment
9. Braking system in off-road vehicles and heavy equipment

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