A new motor-controlled zero-pressure accumulation (MZPA) pallet conveyor from Alba Manufacturing, an OEM based in Fairfield, Ohio, is now in use to eliminate pneumatic clutches and their associated devices, replacing them with new plug-and-play zone-control boxes. The result is a conveyor that can operate at elevations much lower than before, and with reduced maintenance and installation time, the company reports.
Previously, the company’s conveyors moved pallets throughout a plant's production line by using pneumatic clutches and chains. The pneumatic clutches required air piping and constant maintenance. Multiple devices drove up field wiring and programming costs, and elevations below 18 inches were impossible because of zone chains running underneath. The MZPA conveyor the company employed reportedly has solved these problems by removing the pneumatic clutches.
"We wanted to introduce a feature-rich machine that eliminated the problems associated with pneumatic conveyors, while remaining affordable," said Tom Thomas, vice president of sales at Alba. "The MZPA conveyor standardizes on Allen-Bradley controllers that require less maintenance and training time because of operator and technician familiarity with the equipment. As a result, this solution helps speed installation and lowers the total cost of ownership for end users."
In zero-pressure accumulation applications, pallets are coordinated with the rest of the line, moving from one zone to the next at just the right time, preventing a buildup of pallets and alleviating pressure on the flow of items through the process.
Controlling the application provided a complete solution, including sensors, motor starters, motor protection, panel connection system with cables, KwikLink with flat media, and a zone control system. Each zone uses a zone control panel that controls individual zone motors, eliminating mechanical and pneumatic components. Additionally, a power supply panel provides the 24V DC control power and the necessary interconnecting cables. All of the devices required on each zone come preassembled and wired within the zone control panel, which also includes all of the cable and connectors needed to interconnect the zones.
The standard MZPA conveyor package used at Alba includes djustable time delays, sleep mode and signals for flow control logic, which eliminate programming costs and increase reliability. Because the chains associated with pneumatic-clutch conveyors have been eliminated, the conveyor can operate at heights as low as 5.75 inches, compared to the previous 18-inch minimum height limit, the company reports.
To ease costs for end users, the conveyor, along with its associated photoelectric sensors and DeviceNet connections, are plug-and-play and are ready for immediate installation. Accumulation logic is pre-tested at Alba's factory. The installer only has to bring three-phase power to the master power box, minimizing field wiring effort and cost.
"When designing this machine, we considered several options from various component suppliers," Thomas said. "In the end, though, we realized that standardizing on control technology simplifies our ordering process and reduces our learning curve and engineering time. For our end users, a solution [to this problem] meant strong support and familiarity, giving them confidence in the system's reliability and performance."
