Internal Gear Pumps

In last month’s introduction, we discussed how chemical-manufacturing processes require the use of dangerous chemicals, such as strong acids, caustics, solvents, resins, and polymers. Substances that, despite their inherent danger, are necessary for the manufacture of myriad consumer goods and other industrial processes. However, handling and transferring these dangerous chemicals in a reliable way remains a challenge for many users. It is only when chemical processors master this juggling act that they will create a manufacturing operation that is both robust and profitable.

G Series Internal Gear Pump

G Series Internal Gear Pumps feature a unique design that features only two moving parts, a rotor and idler gear, which allows them to operate equally well in either direction and deliver positive, non-pulsating flow of the liquid being handled.


Fortunately for chemical processors, positive displacement internal gear pumps have continually offered the reliability and cost-effectiveness required when handling raw materials and finished products. A leading example of this technology is exemplified in the G Series Internal Gear Pump from Maag Industrial Pumps, Grand Terrace, California. Maag Industrial Pumps is a product brand of PSG®, a Dover company, which is headquartered in Oakbrook Terrace, Illinois.

G Series Internal Gear Pumps feature a simple design with only two moving parts, a pair of coinciding gears called the rotor and idler, making it ideal for precise and consistent transfer of demanding fluids. This design creates a four-step operating process for the G Series pump:

  1. The rotor and idler gears un-mesh at the suction port to create an atmospheric vacuum that draws fluid into the pump. As the rotor turns, the fluid is forced between the rotor teeth and idler teeth.
  2. Continual rotation of the rotor forces the fluid through a crescent-shaped area within the wetted path. The crescent-shaped area divides the fluid and acts as a barrier between the inlet and discharge ports.
  3. As the rotor continues rotation, the fluid is forced past the crescent-shaped area and moves toward the discharge port.
  4. As the rotor completes its rotation, the rotor and idler teeth engage, forcing the fluid through the discharge port of the pump.

This method of design and operation allows G Series pumps to operate equally well in either direction, resulting in a positive, non-pulsating flow of the fluid being handled. Other design features of G Series pumps include a rotatable pump casing that allows for multiple inlet and outlet port positions, single-point end-clearance adjustment, and an enlarged bearing housing at the rear of the pump that allows easy drive-end access to the shaft seal.

G Series pumps are available in cast iron and stainless steel construction. The six models (G1-2 to G1-69) range in size from 1-1/2 to 3 inch ANSI port sizes with flow rates from 15 to 140 gallons (57 to 530 liters) per minute. The cast iron models of the G Series pumps have maximum discharge pressures of 200 psi (13.8 bar) and can handle fluid with viscosities up to 440,000 cSt. Pumps are available with packing or mechanical seals. G Series pumps are also universally interchangeable with 95% of the gear pumps on the market, which reduces system downtime and the need for costly repiping operations.

Maag Industrial Pumps also offers base mounted G Series. This packaged system includes the pump, coupling, coupling guard, gear reducer and motor all mounted on a standard or heavy duty base, designed to minimize deflection and vibration, maximizing the life of key components, while offering easy and accurate shaft alignment.

G Series pump

G Series pumps are available in cast iron and stainless steel construction and are offered in a variety of connection sizes and flow rates.


It’s accepted that chemical processors must deal daily with fluids that are difficult to transfer. Their task is to create a handling and transfer regimen that includes pumping equipment that is compatible with many different types of dangerous chemicals, while also offering reliable operation and cost-effectiveness with regard to maintenance, repair, and downtime. The operating principle of G Series Internal Gear Pumps, from Maag Industrial Pumps, has been proven to be the ideal choice for the handling and transfer of the many different types of chemicals used in many of today’s industries worldwide.


Chrishelle Rogers is the global gear pump product manager for Maag Industrial Pumps, Grand Terrace, California, and PSG®, Oakbrook Terrace, Illinois. Ms. Rogers can be reached at 909.222.1309 or Maag Industrial Pumps is a leading brand of internal gear and screw pumps and a product brand of PSG, a Dover company. For more information on Maag Industrial Pumps or PSG, visit to

MODERN PUMPING TODAY, November 2015 Buyers Guide
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