The Problem
Ground Force uses EPC encoders to measure the rotation of pump shafts and of augers. The pumps deliver wet ingredients, while the augers deliver the dry ingredients. Ground Force uses a straightforward sprocket and ladder chain system to drive the encoders from these shafts and augers.
The encoders are 200 pulse-per-revolution (ppr) incremental units, and their output is fed to a scaling system that converts the pulses to the delivery rate – the rate at which pounds/kilos of mixed product are being delivered by the truck. The rate of delivery is crucial to ensuring the proper mix of components.
A typical truck will use up to four encoders, one for each type of component. The scaled outputs from each encoder are fed to a processor that monitors the various outputs. The processor ensures that the final mixture is, and remains, optimal.
Ground Force’s design requires that the encoders are mounted on the outside of the trucks, so they require an encoder that can withstand an incredible amount of environmental abuse: all types of weather conditions, plus the mud, dust and rough treatment typical in a mining environment.
The encoders also have to be resistant to the caustic and corrosive elements that make up the explosive mixture. These components will rapidly find any weaknesses in an encoder.
The Solution
The obvious choice for Ground Force’s application was a workhorse Cube Accu-Coder® with an HD10 Ultra Heavy Duty Housing. The incremental shaft encoder is reliable and durable. With its ultra heavy-duty housing, it is rugged enough for the demanding environment and resistant to the caustic and corrosive materials it is exposed to during Ground Force’s everyday operations.
Ground Force has used this same basic system for years. It has proven to be so reliable that no alternative design has been found that satisfies their requirements. To quote Alex Ritter, Ground Force’s Chief Engineer, “At this point in time, we are not even thinking about searching for an alternative system, or about changing the design.” This is strong testimony to the ruggedness and reliability of EPC’s encoders, especially given the environment in which they operate in this application.
“I have yet to find another approach that will give me the accuracy I need while still meeting my economic requirements,” Ritter continues. “Moreover, EPC encoders have proven to be basically bulletproof. Once the encoders are installed, they tend to run for a long time and never give me any maintenance problems; and given where these trucks are used, and the corrosive chemicals they carry, that’s really important.”
Ground Force has purchased thousands of encoders from EPC since 1985, and had the distinction of having purchased Encoder’s one millionth encoder.
“We wouldn’t dream of going anyplace else! After all, why change a good thing?” adds Ritter, who considers EPC the “only encoder supplier out there.”
