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The main difference of these pumps' design compared with the gear pump is the presence of big teeth and big cavities in the gears. The pitch of big teeth and big cavities is greater than the pitch of small teeth in 3, 5, 7 or more times (hereafter pitch ratio), i.e. a big tooth can enclose 2, 3, 4 or more small neighbor teeth and similarly a big cavity can enclose 2, 3, 4 or more small neighbor cavities. Besides, the addendum diameter of big teeth is greater than the addendum diameter of small teeth. This simple change in the gear pump design gives the following advantages:
Higher suction lift and ability to deliver high viscous liquids at higher RPM, because high volume of the pocket between two opposite big teeth generates high vacuum at the suction port enabling speed increase when delivering viscous liquids compared with the same liquid pumped by gear pump, thus increasing productivity.
High volumetric efficiency, since gears have high number of small teeth (rated) and high engagement factor consequently, which improves meshing hermeticity.
High hydraulic-mechanical efficiency, because a great part of the liquid is discharged as a result of constantly diminishing large pocket as apposed with tooth engagement of one gear into cavity of the other gear in case of the gear pump. Thus the pumps have lower pulsation.
High fluid maximum pressure at small overall dimensions for "Durable Gear Pump with Different Teeth" and "Durable CIG Pump with Different Teeth", because turning resistance of driven gear is significantly smaller, which causes low meshing circumferential force and consequently low contact and bending stress of the meshed teeth.
Long life operation/high reliability for "Durable Gear Pump with Different Teeth" and "Durable CIG Pump with Different Teeth", because of the small circumferential force, which results low friction forces between teeth, low contact fatigue and consequently less wear. Besides, high engagement factor enhances smooth operation and thus contributes to reliability too.
The "Durable Gear Pump with Different Teeth" and "Durable CIG Pump with Different Teeth" can be used as compressor and air motor as well, because they have high compression/expansion ratio. As an air motor, they are more effective than air gear motor, since they fully utilize pressurized air internal energy because of the higher expansion ratio.
Gear Pump with Different Teeth
Gear Pump with Different Teeth
The prototype is made of plastics by American University of Armenia (AUA) as a students' CAD/CAM project. To see its video in water pumping and photos as well, click here: The prototype of Gear Pump with Different Teeth
Pitch ratio = 3
Pitch ratio = 5
In order to provide better hermeticity, special elastic sealing can be applied between big teeth top land and case contour, such as the one shown below:
Pitch ratio = 3
Pitch ratio = 5
Durable CIG Pump with Different Teeth
Durable CIG Pump with Different Teeth
Pitch ratio = 3
Two Teeth Lobe Pump
Two Teeth Lobe Pump
The invented lobe pumps have similar advantages compared with conventional lobe pump like:
Higher suction lift and ability to deliver high viscous liquids
Higher volumetric efficiency and ability to develop higher pressure, because the cylindrical contours of rotors can be made of elastic material, which will provide hermetic rolling contact between the rotors.
Constant flow, because of constantly diminishing large pocket between lobes as apposed with lobe engagement of one rotor into cavity of the other rotor in case of the lobe pump.
Long life operation/high reliability, since the driven rotor (the smaller rotor with two cavities) generates zero resistance torque. Thus the timing gears can be made of plastics no matter how big is the fluid discharge pressure.
CIG Two Teeth Lobe Pump
CIG Two Teeth Lobe Pump
If you want the pump's 3D CAD models assembled in "Mechanism Design" module of ProE Wildfire 5.0 software, feel free to write me.
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