Weighing Systems & Scales
Load cells are used in bulk material handling systems to gauge the weight and force of a load of bulk material. The purpose of this ability is to test mechanical systems and monitor their output during production times. Load cells are particularly important for maintaining the accuracy of the industrial scales that are used to weight bulk products. Compression and tension are the most common force measurements made using load cells. Many load cells are built with an internal strain gauge, a small device that can measure how much strain is put on an object using electrical signals. Force gauges do the same thing but for push-pull testing or measurement of flow.
The flow of liquid or viscous bulk materials can be measured by pressure sensors. This is useful to determine the rate and force of flow through a bulk system for optimization and efficiency purposes. Digital load cells are the most popular and the most easy way to access the information that sensors pick up during operation. In food processing facilities, load cells play an important role in measuring ingredients before they are entered into a mixture. This precision is critical to the on-going quality of a product. Perhaps the most important function of a load cell is to determine the exact weight of loads, like a loaded pallet. When bulk processors ship their goods, they need to know the precise weight for logistics and billing reasons. Load cells provide readings that are accurate within 0.25%, which is extremely precise for applications where a single load may weigh several tons.
So how exactly does a load cell work? A load cell is designed to convert mechanical stress into electrical energy. Information is received in this way and sent to a data collection system in the device. This is then turned into an output or reading that an operator can see as an item is placed on a scale or material runs through a tube. Analog load cells still exists, but they have been largely surpassed by digital load cells because they are more accurate and easier to read. In applications where a load cell is used to shut off equipment, the cell is designed to sound an alarm when a predetermined event or set of criteria is observed. Load cells can be fitted with multiple gauges. The more gauges, the more sensitive the cell will be to changes and the more accurate its measurements will be. Necessary accuracy, type of force, and response time are among the most important factors that must be considered when a cell is being designed for an application.
Load cells are used in equipment at bulk material handling facilities in mining, food processing, pharmaceuticals, oil & gas, agriculture, and other industries. Although a load cell is very small, it has a huge impact on the efficiency and cost-effectiveness of major operations. Some manufacturers specialize in load cell production and work with industry experts to create devices that perform specifically for certain materials or applications. Others are more general and can be used in many different bulk handling capacities.
Bulk material handlers in all industries rely on scales to weigh their products and accurately determine quantities during packaging, before shipping, or before storage in a facility. Many bulk products are sold or distributed based on weight, so it is important that precise information is available. Scales can be small enough to measure tiny objects, but typically in bulk material handling applications, they are at least large enough to weigh a loaded pallet. Some industrial scales are large enough to weigh an entire loaded trailer or shipping container. Scales are made in many different forms, including: bench scales, hanging scales, and platform scales. A bench scale is raised up off of the ground by several inches or a few feet and may even be moved around a facility as needed. The raised stance of the scale makes it easier to load and unload small to medium sized loads. A platform scale or floor scale is level with the floor and typically has a large platform for weighing large bulk loads. A forklift or other vehicle can be used to move the weight directly onto and off of the scale. A hanging scale suspends loads in the air and gauges their weight based on the amount of gravitational force that they exert.
Scales can have either digital or analog readings. While a scale with a meter and a needle that displays the weight of a load may be accurate, it is not as precise or as easy to read as a digital scale. Digital scales show decimals and make it possible to be highly precise during the weighing of bulk products. In any bulk operation, the most important consideration when investing in an industrial scale is the maximum weight that it is able to measure. Scales can range from a capacity of just a few grams to over 80,000 pounds. Knowing the needs of your application and choosing a scale accordingly will prevent technical errors and allow for the accuracy that your system needs. When bulk products are weighed on a scale, they are usually on a pallet or loaded into some kind of container. The weight of the container or pallet itself can be inputted into the scale so that the only material being measured is the bulk material. If distributors are being charged by weight, it is important that a bulk handler does not also charge them for the weight of the container. To determine the weight of a load, scales are built with hydraulics, balances, springs, or load cells. In more complex scales, a combination of these devices is used.
In most industries, scales are subject to regulatory standards that have been established by the National Institute of Science and Technology. These standards ensure worker safety and accuracy for the measurement of bulk goods. In a bulk material handling system, scales can be placed near other equipment and loaded manually by workers, or they can be loaded and unloaded intermittently by automated machines. In these instances, the machines receive information from the scale that tells them when the load has reached the required weight. Bulk material handling systems in agriculture, food processing, pharmaceuticals, and more all use industrial scales to weigh products before they are packaged or shipped. Sometimes it is necessary to use scales to weigh small quantities that are then added to a larger mixture in a processing plant. Again, accuracy is key to maintain consistency and quality across bulk products in applications like these.
Weigh Batching Systems
Weighing and batching equipment are integrated into bulk material handling systems to ensure that the appropriate quantity of material is utilized, packaged, or shipped. A weigh batching systems can be used to accurately fill containers like bags, drums, or bottles so that each container is filled with the exact same amount of material, or they can be used to ensure that an appropriate amount of materials is added into a batch being mixed. These systems provide accuracy and repeatability in bulk material handling systems. There are several types of weigh batching systems that are used in bulk material handling, and they use what are known as either gain-in-weight or loss-in-weight principles.
With a gain-in-weight batching system, a volumetric feeder is used to feed the material into a weighing hopper. As material is added, the weighing hopper continuously takes weight measurements, and the feeders continue to release material until a set weight is reached within the hopper which triggers a mechanism that signals the feeders to stop. Many applications require that several different materials be added into the batch. In this case, each material is added to the weigh hopper one at a time. Once the set weight for an ingredient is reached that feeder is switched off and the next ingredient feeder is switched on until the next set weight is reached. This process continues until all ingredients have been added. This results in the hopper containing several layers, one for each ingredient since they were added individually. The sensitive automated controls in this weighing system prepare bulk materials for the next stage of the process by carefully controlling the release of substances.
In a loss-in-weight batching system, multiple ingredients are fed into a collection hopper using highly controlled feeders. Each of the ingredient feeders is equipped with a weighing sensor, such as a load cell, to carefully measure the weight of the material within the feeder. As the feeders release material into a hopper, the system tracks how much of the ingredient is released by tracking how much weight was lost in the feeder. This is important in applications where smaller weights are at play and where more exact weight measurements are necessary. Additionally, batch mixing times are reduced down the line because these materials are introduced into the hopper all together instead of one by one, resulting in a blended mixture.
Within these two types of weigh batching systems there is a wide variety of machinery. Machines vary in sizes and can be purchased to reflect the availability of floorspace in a commercial or industrial facility. Because industrial technology has advanced so much in recent years with the development of better digital control and sensors, bulk material weigh batching systems can be more precise than ever before. Full control and display units can be installed in a facility so that operators can monitor efficiency and output. Changes can now be made at the touch of a button, a feature which is especially convenient for suppliers who process high volumes of material for many industries on a daily basis.
Leading Weighing Systems & Scales Manufacturers
Our load cells are manufactured with the highest attention to detail at all stages. Whether it is through the design stage, engineering stage, or through hundreds of tests run daily, we ensure that our products outshine all competitor products. That is why high profile customers like NASA trust us with their business. Find out why we make all the difference by contacting us today!
Tecsis LP specializes in designing and manufacturing load cells for the most challenging applications. Our in-house engineering team will create a one-of-a-kind sensor or modify our standard product to meet your needs. Our state-of-the-art manufacturing facility delivers all industrial load cell configurations including low profile pancake, donut, shear beam, canister, and in-line models, each one integrated with a complete offering of electrical connectors, outputs, and mounting options.
We supply Multi-Axis Force/Torque Sensors. Our F/T Sensors measure all six components of force and torque. ATI F/T transducers use silicon strain gauges for low-noise and high overload protection. Our sensors are used in robotic assembly, robotic material removal, product testing, biomedical and biomechanical research.