Maag Gear Pumps for Sensitive Industrial Applications

Maag has a proven track record in offering a wide range of pump models capable of handling challenging applications with ease. They are clearly the frontrunner in quality and performance among all the Industrial External Gear Pump technology producers. 

Maag positive displacement (PD) pumps are designed to handle any pressure, viscosity, and temperature; even at the same time. As a result, Maag pumps are a great fit for extreme conditions where other pumps struggle to hold up. 

Usually external gear pumps are less suited to handle abrasive fluids. Using four bearings in the pumped medium and stringent mechanical tolerances implies these type of pumps are sensitive to wear, particularly with abrasive fluids or feeds containing entrained solids. For these applications, internal gear pumps are more robust. 

In a certain case, a client’s need was for a transfer pump in a urethane application with 50% CaCO3 used for flexible molding in buildings. Due to the high solid fillers (CaCO3) in the fluid, they were struggling to find a reliable solution to withstand abrasive wear in the equipment. They were exchanging the existing internal gear pumps from a competitor quite often (twice a year). 

Since Maag’s goal is, above all, to propose the optimum and most reliable design to reach the maximum performance with each pumped product, they have focused on the optimization of the pump design with reference to the geometry of the recesses machined on the bushings and gears for many years. As a matter of fact, the geometry of the bearings and gears has significant effects on the delivery of consistent pressure and volumetric efficiency.  

Maag models the complete machine operation and develops a model that provides a detailed evaluation of the flow through the gear profile and allows the simulation of a complete hydraulic system. The selection tool named CAMOS, is based on a discrete parameter approach, and permits the analysis of the flow under a precise characterization of the pump shape and teeth profiles, of the recesses and of the axial (gear sides) and radial (between tooth tip and housing) gaps.  

The balance for this application was to avoid wear of the components without losing volumetric efficiency by increasing the radial and axial gaps.   

Main features of the selected pump are: 

  • D6C.S single mechanical seal with Sintered Silicon Carbide sealing ring, 

  • L51 ceramic bearings 

  • Z15 spur gears in thru-hardened stainless steel  

  • Cast steel body 

D6C.S type seal with SsiC sealing ring is the most suitable for the abrasive fluids and L51 type ceramic bearing is extremely hard, very high chemical resistant and very good for abrasive fluids. 

The Maag pump was installed in April 2017 and has been still running after more than a year making the client very happy.

Maag RX56 20180929