Gear pumps verses Wanner piston pumps

Most of our competitors use either a gear pump or a Wanner piston pump for the high-pressure pump on their systems. During our time at CNC Enhancements we tried both, and after experiencing both, we at CNC Accessories choose to use gear pumps for our standard system. But we can build it with the Wanner piston pump as an option. The Wanner pump is a very expensive pump designed for pumping liquids with debris in it. Wanner sells this pump as being re-buildable. The Wanner pump uses rubber diaphragms to keep the coolant and metal chips from getting into the oil filled pistons and crankcase area. If the filter before the pump is not cleaned or replaced on a regular basis, then the diaphragms become damaged by the sharp metal chips allowing the coolant with metal chips to start mixing with the crankcase oil. At first this will not cause any noticeable change to the coolant flow to the machine tools. If the operator or maintenance department finds the coolant in the crankcase when this first starts, then the pump can be rebuilt with an inexpensive kit from Wanner. However, if this contamination of the crankcase oil is not found soon enough, then the microscopic metal chips will jam the oil filled pistons causing the piston shafts to disengage from the wobble plate. The piston shafts are then free to fall out of place and start banging around in the crankcase. The chips will also damage the crankshaft bearing. The point where the coolant pressure starts to be noticeable affected is after one or more of the pistons have jammed. The pump can no longer be rebuilt at this point using the kit from Wanner, and instead must be replaced. The gear pumps, although they are not re-buildable, will last about as long as the Wanner pumps. The Wanner rebuild kit is the least expensive way to fix your system, assuming it is re-buildable. However, if it is not re-buildable, then the gear pump is much less expense to replace then the Wanner pump.

Your choice of systems comes down to the type of employees you have. If you have very good conscientious employees that will change the filters on a regular basis, and check the crankcase oil for contamination regularly, then the Wanner pump is your best bet. If, however, you have employees that run the machines until they stop, then the gear pump will cost you the least to replace, and therefore is your best bet.