Gear Pump

Taiko Kikai's gear pump is provided with segmental gears, which continuously contact each other on one point, as its standard.
Segmental gear eliminates confinement phenomena, which occurs on conventional involute gears, to realize the positive-displacement pump that has small noise, small vibration, and long lifetime. Taiko Kikai's gear pump is used for transferring, for example, lubrication oil, fuel oil, and chemical liquid.

What is Gear Pump?

Principle of operation

Gear pump is a kind of positive-displacement pump that captures the liquid into the gaps formed by the meshing of the gears rotating inside the casing so as to let the liquid go along the inner periphery of the casing through from the suction-end to the discharge-end.

Taiko Kikai's gear pump is provided with segmental gears.

Principle of operation image

Gear shaft

Comparison of gear shapes of gear pump

Segmental gear (Taiko Kikai's gear pump)

Segmental gear (Taiko Kikai's gear pump) image

Continuous one-point contact prevents confinement phenomena

Small vibration and noise

Involute gear

Involute gear image

Confinement phenomena
Two-point contact of gears lets the liquid be compressed (A→B) and expand (B→C), which causes vibration and noise.

Features of segmental gear

  • 1Low power consumption
  • 2No bubbles in the discharged liquid
  • 3Handles high viscosity liquids
  • 4Small noise in operation
  • 5Extremely low performance-degradation after long term use
  • 6Smooth rotation with one-point continuous contact gears
  • 7Double-helical configuration counterbalances the thrust load


Bearing of gear pump

Bearing is a mechanical component that literally bears the shaft
Bearings are categorized into the following two types with their configurations

1Slide bearing

The bearing contacting a shaft to have a sliding motion on the contacting surface

Slide bearing image

2Roller bearing

The bearing provided with rolling elements, such as balls or rollers, to have a rolling motion

Roller bearing image

Features of slide bearing of gear pump

  • 1Simple configuration
  • 2The lifetime of a sliding bearing is semipermanent when it is, under the ideal conditions, supported by the oil film formed with the handled liquid
  • 3Quiet operation
  • 4Impact-resistant

Shaft seal

Shaft seal of gear pump

1Gland packing

Gland packing image
  • ・The packing made of square-braided yarns. Gland packing is installed on a shaft in a pressed condition against the shaft's surface to get a sealing function.
  • ・Low price and easy to handle
  • ・Because of its sealing mechanism, a little amount of the handled liquid must be leaked from the sealed portion in operation (one drop / second)
  • ・Leakage amount can be adjusted with tightness of packing installation. Too tight installation can lead to early abrasion of packing and shaft.

2Oil seal

Oil seal image
  • ・Configured to provide a sealing function with rubber-made sliding-contacting portion
  • ・Low price and easy to handle
  • ・Leakage amount is extremely small, however, leakage amount increased with deterioration cannot be adjusted
  • ・Pressure limit of general oil seal is up to 0.03 MPa at maximum

3Mechanical seal

Mechanical seal image
  • ・Rotating seal ring and static seal ring are configured to slide on each other to provide a sealing effect
  • ・Expensive price and complex configuration. Skill for installation is required
  • ・Extremely small leakage amount, abrasion-proof, and long life-time when used appropriately

4Mechanical seal (quenching type)

Mechanical seal (quenching type) image

Oil quenching type is used when the handled liquid is fuel oil.
The residue is left when handled liquids, such as fuel oil, exuding from the sealing surface evaporates. This residue deposits on the sliding surface, which can lead to leakage from the seal.
Filling the atmospheric-end of the mechanical seal with some lubrication oil keeps the sliding surface from the atmosphere to prevent the acidization of the fuel oil.


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