Simple Solutions That Work! Issue 10

Foundry mixer pumping systems can be basic, or complex depending on the exact needs of the foundry. We will review some of the different styles available and point out some of the advantages of each. and leak over time. The pumps can be rebuilt which will reduce the leaks, but they will still occur at a slower pace. Magnetically coupled gear pumps – these are a more recent style of pump and have been used for the past several decades. Most new mixers being built now will have this steel-bodied style as the standard offering. As you can imagine, the major benefit of this style of pump is that it does not leak like the shaft coupled units do. Due to the completely sealed housing and the magnetic coupling, there are no seals that are separating moving parts from open air, so there are very few places for leaks to occur. These pumps are usually more accurate and repeatable than a shaft coupled unit also. The disadvantage to this style pump is that it is more costly to purchase than the shaft coupled unit, but this can easily be overcome by reduced maintenance for rebuilds and also avoiding environmental issues brought on by shaft coupled pumps that leak. Since this unit lacks a direct drive like the shaft coupled unit, the torque that can be induced to the pump is only as strong as the magnet used for the coupling. Resin density, temperature range, and throughput requirement will determine the ideal magnet strength to be used. Stronger RICH McNEELY National Sales Manager PALMER MANUFACTURING & SUPPLY, INC. ARTICLE TAKEAWAYS: • Differences between direct and magnetically coupled gear pumps • Benefits of two and three-way valves • Advanced systems for safety UNDERSTANDING MIXER PUMPING SYSTEMS 56 PUMP TYPES Direct shaft coupled gear pumps – These have been used in the foundry industry for nearly the last century and are the most common type of pump that will be found on most mixers already in use. For most foundry applications, these pumps will have a cast-iron body, a steel shaft, a gear, and a rope-style packing. The advantages to this style of pump are that it is very simple and serviceable by most maintenance technicians, and since they have a direct drive, the torque of the pump is as strong as the motor driving it. They are also the lowest cost style of pump that is used regularly. The disadvantages to this style of pump are that due to the rope style packings and the rotating shaft, the pump will seep resin