Blenders Incorporate Custom Weighing Devices

Many finished products are manufactured by combining a number of ingredients. This can include pharmaceuticals, where a variety of active components may be mixed with binders, fillers, flavoring agents and preservatives. Likewise, food items can incorporate grains, dried or processed fruits, sweeteners, colors and flavors. Many different types of chemicals require careful and precise blending of a wide variety of ingredients. Metal processing may combine different powdered metals with binders. Similarly, plastics include virgin material, colors and dyes, reground waste plastic, ultraviolet inhibitors, flow and anti caking agents, and others. Arlyn Scales designs the weighing and control components of blenders to the specifications of the blender manufacturer. These are actually a type of customized industrial scale. As with other types of electronic scales, they include material receiving areas, weight sensing devices to measure the amount of received material, electronic readouts to provide information to the blender operator, control electronics, and communication capability. Industrial blenders usually need to provide hoppers or other containers to hold the materials that are being mixed together. Depending on the finished product, there can be just two or three ingredients, or twenty, thirty or even more. These hoppers must have an actuation system that feeds materials into the blending chamber when commanded. If it is a gravity fed system, the actuator may be as simple as a solenoid that activates an air cylinder that opens a hatch in the hopper. Another common actuator is a screw augur which is sent a signal to turn, and feed out the material. Vibrating feeders can accomplish the same function, as can valves and pumps in the case of liquid ingredients. One method of feeding out the proper amount of the material is to simply weigh it as it is dispensed. Feed can start at a rapid rate. As the weight value approaches the desired weight, the controller can command the feeding device to slow the feed rate. This will aid in the effort to reach a precise weight result. In many blender applications, the first ingredient measured is considered to be the primary one. This may be the base of a paint formulation, which may include more that ninety five percent of the final material. In these cases, the primary ingredient is considered to be the determining factor for all other ingredients. If there is a slight overfeed for the primary, than each of the remaining ingredients is re-calculated to make them match with the primary. The weight sensing devices in most blenders can be strain gage load cells. Typically, these are metal blocks which are machined into a shape that will allow them a small amount of bending as a load is placed on them. Most industrial scales use load cells for accurate weight determination. While there are a wide variety of standard cells available, blenders may require a custom designed unit. The weighing hopper may have to be mounted in a particular manner. A hatch in the hopper may need to open in a specific direction. Arlyn Scales manufacturers standard load cells for their standard line of industrial scales, but also manufactures custom load cells when required for specialty applications. The load cells develop an electronic signal which is proportional to the amount of material. This signal is interpreted by the blender controller. The controller must operate in a real time environment, as it will send signals to the feeder devices to control the materials. Generally, the controller will determine its operations based on various recipes that have been entered for the blended materials. It will also collect data in its internal memory for collection and analysis purposes. Because the blenders may operate on a 24 hour a day basis, the memory must be sufficient to collect all of the data from each blending cycle. External memory devices, such as USB flash memory sticks, may also be used for this purpose. The blender controller must be designed in a manner that allows the operator to easily enter the necessary data, view the system operation, and retrieve the necessary information. The best industrial blenders now incorporate a color touch screen for the Graphical User Interface (GUI). This provides clear, concise information of the current status. The screen displays only those buttons or controls that are needed for the specific input required at that time. For example, the operator may go to an on-screen menu to select the recipe that will be formulated. Once the correct recipe is retrieved, the screen can request the overall batch size. Other operating parameters can also be entered. When the blending operation starts, the screen can display updated status reports, and buttons can appear to allow the operator to pause the process, or even stop it when necessary.