June 23 2015
Guest Blog by: Jack Steinbuch, Equipment Engineer at Cleveland Vibrator Co.
There are a wide variety of vibrating tables available to pack material in containers. Flat vibrating tables or packers are commonly used for this application where an empty container is manually placed on the table, filling begins, at some point during the filling process the vibrating table is started to begin packing and finally you end the filling cycle and turn off the table. While this manual operation fits the needs of many operators, they may not be aware that there are alternatives that allow a more automated operation.
Now that we’ve got our feet wet, what about making the operation more automated? Grid Top Tables are ideal for a more automated approach. These tables are designed to interface with gravity or chain driven live roller (CDLR) sections. Advanced automation can be achieved by using a scale or load cells. You then have two options, weighing on the roller section or weighing on the vibrating grid table. In either case, to make this operation fully automated, you need to use a CDLR with a photo eye to stop the empty container under the fill device. You also need to have some type of “brain” which can be relay logic or PLC (programmable logic control).
Weighing on the roller section reduces the level of automation, but is preferred by those who have concerns about vibration affecting the scale. You have a period of time when the grids are raised to pick the container off of the rollers and therefore the scale to begin the vibration cycle. Weighing resumes when the vibration cycle is completed and the grids are lowered to return the container to the rollers. Your controls need to provide a timing device to set the length of time for the vibration cycle as weight is not being read at this time. Once the container is returned to the roller section, you can use the scale to end the filling and lastly re-start the CDLR to remove the filled container and simultaneously bring in the next empty container.
You will have greater control of automation when the vibrating table is mounted on the scale. The operation begins the same as described above, but now when the empty container is in position under the fill device, the grids are raised and the empty container is lifted off the rollers so you can read the weight. The scale is tared (reads “0”) and filling begins. Now you can use the weight of the product to signal the beginning and ending of both the filling and vibration cycles. Please keep in mind: the grid top, when raised, is isolated from the base support structure which is typically mounted on the scale or load cells. Negligible vibration is transmitted and the performance of most scales is not affected. The grids automatically lower the filled container after filling ends when the final weight is reached. The filled container is then removed as described above. This automatic cycling continues until the operator needs to stop the system.
Automation can also be achieved for smaller containers where belt conveyors are preferred for handling. A vibrating belt table can be inserted in the conveyor line after the containers are filled. The filled containers then transfer from a belt conveyor to the belt table where the container is vibrated as it is being conveyed. The table length is determined by the belt speed desired and the amount of vibration time required to settle the product. While this equipment may not necessarily provide the optimum vibration cycle since vibration does not begin during the filling process, it definitely shortens production time.
You now have some ideas on how to add automation to your filling/packing process. Any of one of these products will reduce labor and production time.