By Frank Bray, CMRT, Sr. Mechanic, SUEZ N.A. (Environmental Services)
Efficiency and innovation are what drives a water system on the path to success. When I started working at the Hinckley Water Treatment Plant in 1995, there were various pieces of the operation that were in need of enhancements, but the budget just was not there.
I often brag that I have improved many things and processes in my tenure at the plant, but my greatest accomplishment has been the Bray Chunk Buster. The story of how the Bray Chunk Buster came to be began with a problem that has affected many water treatment plants. By taking the solution in-house, we saved thousands and opened the door for my colleagues to bring their ideas to the table for a more efficient operation.
The Hinckley Water Treatment Plant uses soda ash and lime for pH adjustment and corrosion control in the municipality’s distribution system. Soda ash is trucked to the plant and unloaded into an outdoor silo, where it is vacuumed into the plant through a 6-inch, 6- vane rotary airlock valve under the silo and then into the receiver bin. Once in the receiver bin, it is fed into a slurry mix tank and into the finished water.
When soda ash comes into contact with moisture, it hardens into chunks. Many times, extremely hard chunks will pile up on top of the rotary valve, restricting movement of the product into the receiving bin, eventually thinning out the slurry. This often trips a low-pH alarm that the staff—or, after hours, the standby operator—must address by removing the chunks from the top of the rotary valve to restore the flow of product to the receiver bin. This issue is not only labor intensive, but it can be costly (as overtime pay to the standby operator accumulates), cause water quality issues, affect operator morale and be hazardous to the operator’s safety.
It was apparent to all at the plant that a solution was needed to eliminate, or at the least decrease, the number of calls to remove the chunk build up from the rotary valve. Between 1999 and 2000, research was conducted to assess a grinder that could handle soda ash chunks of this size. The estimated cost at that time was approximately $25,000 with some modifications to the rotary valve system, which would be an additional cost. Due to the high cost, the grinder never became a reality at the plant.
In 2017 when the new contract operator, SUEZ, took over the facility, they immediately saw the need to eliminate the soda ash chunk deficiency. Once again, the team received a quote for a mechanical grinder to fill the space between the rotary valve and the bottom of the silo from where the soda ash flows. The space would still require modifications at a total cost of just under $50,000.
After much discussion, the local SUEZ operations team decided to take a chance on an idea I had, which was to manufacture a grinder myself. On a much smaller budget, I began engineering the basic design for a grinder that would work best for our facility.
I used a local metal fabrication shop to make the basic shell, and order the necessary equipment such as gears, sprockets, chains, and seals obtained to engineer the project. The essential features I wanted for this grinder included:
- Visibility into the top of the grinder to check the product flow and for chunks
- No separate power source be used to run the grinder
- Easy on-going maintenance for local operators
It took me a number of months to complete the first grinder, working on it an hour here and an hour there.
I used needle roller bearings and hard felt as the grease seals, and a series of gears and spacers on two shafts. I cut “V’s” into the gears to allow chunks to fall into them, so the grinders could get a “bite” of the chunk and not allow the chunk to just ride on top of them. I made the drive shaft longer than the auxiliary shaft, to accept the drive sprocket. The auxiliary shaft is driven in the opposite direction by drive gears on both shafts next to the shell of the grinder. This motion allows all the grinders to spin toward each other, and “grind” the chunks downward into the center of the grinder.
Finally, in March of 2019, the Bray Chunk Buster was complete and put online, but like with any great invention, there were minor problems at first. The grinders were too aggressive in breaking down the harder chunks and would periodically make the chain skip on the sprocket, making it sound as though the Chunk Buster was coming apart. I realized that the grinding mechanisms needed to be less aggressive. I decided to build a second soda ash grinder, which was named the Chunk Chewer. The Chewer allows for a finer grind, alleviating the noise that occurred with the ground gear formation.
Since August 2019, we’ve had minimal overtime call-ins for soda ash chunks. The Chunk Buster and Chunk Chewer saved almost $3,000 in the first year of being in use. I take great pride in having led this initiative and saving my team thousands of dollars in upgrades.
This solution is just one example of how one employee, if given the chance, can change the course of an operation. I’m lucky enough to work with a team that embraces creativity and continues to promote in-house innovation.