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Internal Eccentric Gear Pump
A picture of our Internal Eccentric Gear Pump

Internal Eccentric Gear Pump

Our Internal Eccentric Gear Pump is a reliable and efficient solution based on the simple “gear within gear” principle. They feature a large internal gear with internal teeth and a smaller gear (pinion), separated by a fixed crescent to achieve positive displacement. This ATEX-available pump is capable of pumping viscous fluids with exceptional performance at low speeds, low pulsation and a smooth flow for consistent product quality.

Typical applications for our Internal Eccentric Gear Pump:

  • High-viscosity fluids: Resins, paints, inks, adhesives, polymers, bitumen & asphalt
  • Food: Corn syrup, chocolate, vegetable oil, peanut butter
  • Hygiene: Soaps, surfactants, pharmaceuticals
  • Petroleum products: Glycols, chemical processing
Overview

Operating Principles

The simple “gear within gear” principle of Internal Eccentric Gear Pumps means that there are only two moving components within the process medium. The positive displacement is achieved by the filling of the cavities between the teeth of both the rotary and idler gears located in the pump head. With each revolution, a fixed volume of fluid enters the casing through the suction port, filling the space between the teeth of the gears. The crescent within the pump head then separates the fluid as the idler gear turns on the pump shaft.

Image 1: Fluid entering the pump

The orange-coloured section in the image represents the process medium as it is entering the pump suction port and the pump casing & filling the cavities between the Idler Gear (Red) & Rotary Gear (Brown). The three arrows indicate the direction of fluid passage through the pump and the rotational direction of the gears.

Image 2: Fluid filling the cavities & split of flow

As the fluid progresses through the pump head and fills the cavities between the gears, it is also separated by the crescent shape in the pump head, which acts as a seal preventing backflow between the suction & discharge ports.

Image 3: Pump almost flooded

As the fluid fully fills the casing, all cavities between the gears are completely filled in the form of locked pockets of fluid to guarantee absolute volume control and enable the pump to deliver a fixed volume per revolution.

Image 4: The pump is flooded & starts to discharge the process medium under pressure

Once the pump is fully flooded, the rotor and idler gears mesh together and form a liquid seal which is equidistant between the pump ports, which then enables the fluid to exit the discharge of the pump under pressure. The delivery pressure is dependent on the installed power of the motor.

Operating Principle of Yildiz Eccentric Gear Pump

Features & Benefits

The External Gear Pump range features many benefits, some of which include:

  • Ability to pump fluids too viscous for Centrifugal Pumps
  • Versatile across thin solvents to thick slurries and ideal for precise dosing (1cp to over 1,000,000cp)
  • High mechanical efficiency across different pressures and varying flow
  • Efficient suction lift applications and self-priming capability
  • Quiet operation, low pulsation and smooth flow for shear-sensitive products
  • Bi-directional and reversible flow
  • ATEX available for use in hazardous environments
Specifications
Max Capacity (m³/hr) 200m³/hr
Max Pressure (Bar) 15 Bar
Viscosity (cSt) up to 55,000 cSt
Max Speed (rpm) 1400 rpm
Max Temperature (°C) 200°C
Materials & Limits
Connection Sizes 3/8″ – 8″
Capacity Range 0.1 – 250m³/hr
Pressure Range 1 – 15 Bar
Temperature Range up to 200ºC
Speed Range 20 – 1720 rpm
Viscosity Range 20 – 5,500 cSt
Pump Body & Cover Cast Iron, Spheroidal Cast Iron, Cast Steel, Stainless Steel AISI 304/316
Gears Spheroidal Cast Iron, Cast Steel, Stainless Steel AISI 304/316, CrNi Stainless Steel
Bearings SnBz12 Bronze, Carbon Graphite, Silicon Carbide, Hard Metal Coated Steel
Sealing Soft Seal / Packed Gland, Rotatherm Seal, Lip Seal, Mechanical Seal, Cartridge Type Mechanical Seal

 

Sizes Available:

Model Max Capacity (m³/hr) Max
Pressure (Bar)
Viscosity Range (cSt) Max Speed (rpm) Max temperature (°C)
Bareshaft units with In-Line Connections for Low Flow & Low Viscosity Fluids & High Pressures
YMK ¾ 0,4 15 10 – 1650 1400 100
YMK ½ 0.8 15 10 – 1650 1400 100
YMK 1 2 10 10 – 1650 1400 120
YMK 1½ 5.7 12 10 – 1650 1400 200
YMKU 1½ 6.7 12 10 – 1650 1400 200
YMK 2 9 12 10 – 1650 1400 200
Bareshaft Units with 90º Connections for Higher Viscosity Fluids & Medium Pressures
YP 1 3 7 10 – 55000 1400 100
YP 1½ 5.5 7 10 – 55000 1400 100
Heavy Duty Bareshaft Units for Higher Viscosity Fluids, Flows & Pressures
YK 1 3 14 10 – 55000 1400 200
YK 1½ 6 14 10 – 55000 1400 200
YKU 1½ 7 14 10 – 55000 1400 200
YKF 20 0 15 14 10 – 55000 900 200
YKKF 2 11.6 14 10 – 55000 500 200
YKF 2 15 14 10 – 55000 500 200
YKF 2½ 25.5 14 10 – 55000 500 200
YKUF 2½ 32 14 10 – 55000 420 200
YKF 3 32 14 10 – 55000 420 200
YKBF 3 55 14 10 – 55000 400 200
YKF 4 55 14 10 – 55000 400 200
YKYF 40 0 90 14 10 – 55000 400 200
YKBF 4 120 14 10 – 55000 400 200
YKF 5 110 9 10 – 55000 280 200
YKF 6 135 9 10 – 55000 350 200
YKF 8 200 9 10 – 55000 220 200
Close Coupled Units for Low to Medium Viscosity Fluids & Pressures
YMB 1 3 10 10 – 1650 1400 70
YMB 1½ 5.7 10 10 – 1650 1400 70
YMBF 2 15 5 10 – 5500 500 70
YMBF 2½ 23 5 10 – 5500 450 70
YMBUF 2½ 32 5 10 – 5500 400 70
YMBF 3 32 5 10 – 5500 400 70