From mining and agriculture to logistics and manufacturing, businesses rely on bulk weighing and monitoring solutions to ensure optimal inventory management, resource utilisation, and regulatory compliance. Yet often the people making these equipment choices don’t have the knowledge or experience to make the right choice.
This white paper aims to empower these professionals with knowledge and insights necessary to drive the right choice of bulk weighing equipment for optimised efficiency, reliability, and profitability in their operations.
Weighing the pptions
Minprovise International, a provider of mining equipment and contractor services, and Rice Lake Weighing Systems-Master, a global manufacturer of weighing-related products for measurement and automated process control, formed a new channel partnership when Thermo Fisher discontinued a range of Ramsey bulk weighing products in 2023.
This partnership offers bulk weighing and monitoring solutions to the Australian market. There are often several ways to measure the flow of a bulk materials, and the user could lack the knowledge and experience to make the right choice of measuring instrument. In addition, there are also preconditions that can influence this choice, such as desired accuracy, verifiability, hygiene, ATEX, keeping clean and degree of maintenance. Any one of these can tip the tip the scales towards an incorrect choice.
Belt weighers and belt scales
In its simplest terms, a standard in-motion weigh system is made up of the weigh platform with either two, four or six load cells, a speed sensor, a controller/integrator and some form of calibration weight.
To work well, a quality weigher must fit correctly into the desired location on the conveyor, it must be rigid with minimal deflection under maximum load and it must be long enough to give the product enough “dwell time” in the weigh zone for the load cells to sense the product on the belt. Provided these conditions are met, the weigher will work. What sets weigh systems apart is the quality of the integrator.
Simply put, for an integrator to deliver accurate information, it needs to be programmed using the correct parameters. It must also be simple to use, easy to program and stable under all conditions. The Rice Lake Masters 1280 ticks is proven to achieve all these objectives. It is also designed to be extremely user friendly and simple to program.
The Rice Lake Master Model BS14 range is a fully floating weigh system that is available in either a two, three, four and six idler configuration. This weigh system, combined with this class leading integrator/controller the 1280D Enterprise, with inbuilt webserver and optional digitiser along with high quality speed sensor encoder options make Rice Lake Master a brand of choice, being ahead of the game with features, design and dependability that is unmatched in the industry.
What about accuracy?
The stated accuracy of belt weighers can range from +/- 2.0 per cent through to +/- 0.125 per cent. Most application data sheets received from clients request a specific accuracy, however it is worth noting that accuracy can only be verified when the calibration results are checked against a known weight such as a recently certified truck weigh bridge or a recently certified check weigh bin.
To achieve the desired accuracy, the weigh zone must be correctly set up and optimised for that particular conveyor belt system. Most belt weighers are used for in-process weighing, in which case they are calibrated using a correctly sized stored-in place billet weight or calibration chain. In these cases, it is repeatability rather than accuracy that is measured.
For more detailed information on how to best to prepare and set up a conveyor system to achieve a desired accuracy, the following resources are recommended:
- Golden rules of weighing, BELT SCALE HANDBOOK – Application Guidelines for Installing a High Accuracy Conveyor Belt Scale.
- NITP 6.5 – National Instrument Test Procedures for Continuous Totalising Automatic Weighing Instruments (Belt Weighers).
Both resources are free and available on request from Minprovise International.
Weigh belt feeder weighers
Weigh belts and weighing belt feeders are designed according to specifications, and are ideal for a wide variety of industries, including food, mining, quarries, bulk material blending, process control, also truck, barge or rail load-out applications.
Weigh belt feeders help ensure accurate and consistent weight output by using a controlled in-feed and belt speed. This optimises product flow and dosing to maintain the highest possible product quantity. The controller regulates the bulk flow using the measured value and preset feed control. Rice Lake weigh belt feeders integrate Master belt scale frames with Rice Lake’s 1280D digital weight indicator/controller.
Screw weighing systems
A screw weighing system uses the same principles as a belt weigher to measure weight except the conveying system is a screw rather than a belt. The system uses a short screw to convey the product. Special pivot points are placed at the inlet, and a load cell is positioned towards the outlet to hang the screw for measurement.
The weight (kg/m) is determined using pre-feed control. At both the inlet and outlet of the screw, there’s a flexible low friction connection to enclose the product and ensuring accurate weighing. The screw speed (m/s) is tracked with an encoder on the shaft. Once again, the 1280 Enterprise weighing processor is used to control the feed and totalise to throughput.
Screw weighing systems generally achieve a process accuracy of up to +/-2 per cent. Product type and product flow characteristics are used to determine the type of housing material and surface finish the screw requires.
A key benefit of screw weighing is that it’s a controlled dustproof environment designed to convey and process products that have challenging “flow” characteristics.
Bulkslide flowmeter
The Bulkslide flowmeter measures flow rate from vertically falling material. Product flows down a curved chute at a consistent speed, the centrifugal force acting on the slide is measured by a load cell. This force measurement is directly proportional to flow and accurately calculated in kg/hour or ton/hour.
The housings are available in painted steel or stainless steel. The inlet chute is either made of stainless steel or Hardox, the world’s leading abrasion-resistant steel designed to accommodate abrasive products. In case of high wear, it is also possible to cover the sliding plate with ceramics. A high temperature version is also available, where products up to 160° Celsius can be measured. The device is also dustproof and requires very little maintenance.
Bulk weighers
A bulk weigher consists of a weighing hopper with a valve and a buffer hopper above it. Optionally, a small hopper can be placed under the weighing hopper to ensure continuous storage. Product flows continuously and is weighed in batches for high accuracy.
Initially, the buffer hopper valve is open while the weighing hopper valve is closed. Product flows into the weighing hopper until it’s full. Once full, the buffer hopper valve closes, and the weighing processor calculates and stores the weight. The weighing hopper empties, valve closes, and zeroing occurs. Product continues flowing and accumulates in the buffer hopper and the cycle repeats. Smooth product flow is crucial for these systems.
Conclusion
Expertise and knowledge are crucial when making choices about bulk weighing and monitoring solutions equipment for optimised efficiency, reliability, and profitability in operations.
The services of Minprovise International include support in the selection of weighing systems, supply, installation and commissioning plus ongoing maintenance support.
After a nine-year channel partnership with Thermo Fisher Scientific that lasted until the discontinuation of their bulk system products in 2023, Minprovise entered into a new channel partnership with Ricelake Master Weigh Systems.
It is a company with a strong focus on the manufacture and supply of high quality, precision products, making them a perfect fit for Minprovise.