It would be nice if every weighing requirement was exactly the same. A single line of industrial scales would fulfill all situations. If there were very minute amounts of materials that had to be weighed with high precision, a laboratory balance would be employed. If some ingredients needed to be combined to formulate a small package, a bench scale would be chosen. This type of small digital scale is available with capacities ranging from one or two pounds up to 100 pounds. Platform sizes tend to vary with the capacity of the bench scale. If the ingredients in question were being dispensed into a pail or tank or drum, a drum scale would be selected. Larger packages are weighed on platform scales. These generally are available up to 500 lb our 1000 lb. Platform sizes tend to be considerably larger. A standard size is 20’ x 27’, but there are alternate sizes up to 30’ x 30’ or even 36’ x 36’. A fairly similar unit is a veterinary scale or animal scale. A typical platform scale is modified with a rubberized platform mat, and the software is changed to allow an accurate weight to be measured for an animal that may not stay still. Even larger items could be weighed on a floor scale. These could include pallets, tanks or other large containers.
Because industrial applications are so varied, there are many times that a standard electronic scale will not provide a useful solution. For these situations, it may be necessary to design a unique industrial scale. It may need to accept the item to be weighed in an unusual manner. The platform size may be different than the standard industrial scale. The electronic controller may have to take certain actions depending on the weight being measured. The readout may have to be customized. It may be necessary for the weight data to be communicated in some special fashion. Some companies, such as Arlyn Scales Custom Devision, specialize in customized scales and custom weighing equipment. There are a number of components that generally constitute a complete industrial scale. One of them is a the load cell, which may have only one for the entire scale, or a number of them connected together. Load cells are made from a number of different types of metals. They are fabricated into a precision shape. Strain gage resistors are applied to surface sections of the metal. As the metal bends when a weight is applied, the strain gages can measure the amount of bending, and therefore the amount of weight. Custom weighing solutions may require custom load cells. The type of metal should match the environment. Usually, stainless steel alloys are the best choice, giving excellent corrosion resistance along with the best strength and ruggedness. The size of the load cell may have to be customized to match the type of items being weighed.
Another important part of the scale is the section that accepts the materials that need to be weighed. While a rectangular platform may be appropriate for a cardboard box, a hopper may be needed for weighing a powder or pellets. A particular shape of tank or bottle may be needed for weighing some liquids. Animals may have to be weighed on a platform that includes some sort of a cage. The digital display offers a wide variety of customized choices. Standard LED or Liquid Crystal Displays (LCD) may need to be placed in specific locations, to make them easily read by the scale operator. The display may need to be of a scoreboard type, with very large digits. A color touch screen readout provides a very flexible, easy to use system with a Graphical User Interface (GUI). These can provide only the information that is necessary for the function currently being accessed, reducing clutter on the display. Control buttons can appear and disappear as needed, avoiding operator overload from too many functions at one time. The custom scale display controller can become quite sophisticated. It may have the ability to measure flow rate of dispense or collection, using the change in weight of a tank during a measured time period. It can control valves, solenoids, pumps, augurs, and other types of feeding devices. There may be the need to control hydraulic or pneumatic cylinders to empty a hopper, or allow materials to feed into the hopper by gravity. The data may be made available through a USB interface into a computer system. Alternatively, the data could be connected through an Ethernet port where it becomes accessible from anywhere on the Internet.
