Loss-in-weight Feeders

THAYER Loss-In-Weight feeders come in a variety of sizes and shapes, and can incorporate various volumetric devices, depending on the material, handling characteristics and flow rates to be encountered. Flow rates may be as low as 2 grams/min. to over 100,000 lb/hr. The most versatile feeders include the screw feeder and the vibratory pan feeder. Thayer Scale offers the broadest range of Loss-In-Weight feeders of any manufacturer. Each Loss-In-Weight feeder is designed to provide precision class accuracy and repeatability in the most demanding process environments. Thayer Scale offers a powerful set of proprietary add-on accessories that defeat the problematic flow issues encountered by industry; bridging, flushing, adhesion, and cohesion to name just a few. Comprehensive process solutions that can only come from a company with over sixty years experience.

  • Extended operating range.
  • Scales built to take abuse.
  • Load cells can be accessed /replaced without feeder/weigh hopper removal.
  • Flexible mounting options including floor mount, rotating base, stationary legs, wheel/caster, and fork lift base, and/or “over process” suspension.
  • Fast access for cleaning.
  • No-Tools changeover.
  • Self-empting designs.
  • Handles delicate and/or fragile materials without damage.
  • THAYER is proud of the fact that it has designed and manufactured some of the most accurate industrial weighing equipment in the world, based on its flexure plate and flexure cable Force Measurement Suspension System (FMSS). It has supplied defence agencies with equipment that weighs uranium ingots weighing as much as 600 kilograms to an accuracy of 1.0 gram. It has supplied Loss-In-Weight feeders for critical manufacturing of liquid and dry rocket propellants, feeding difficult components to accuracies no other manufacturer could achieve.

    THAYER SCALE Loss-In-Weight Vibratory Feeder Special Features and Benefits

    Thayer Scale has spent many years developing the Loss-In-Weight Feeder and control system for use with vibratory feeders. Since virtually all of the controllers on the market were originally designed for use with a screw feeder, it should not be surprising to find that very few of them have the versatility to cope with the special requirements of the vibratory feeder type. Without (certain) special control features, the vibratory feeder cannot be controlled effectively in a volumetric mode, nor can it be controlled gravimetrically over a wide operating range without making controller adjustments to suit its non-linear characteristics. With complete absence of motors, bearings, seals and lubricating fluids, along with the uncontested pulse free delivery “smoothness” at maximum turn down, the vibratory feeder has powerful advantages over the screw feeder in a great number of applications.

    Belt Scales & Insertion Weighers

    Outdoor conveyor weighing of dusty fines and “stone like” aggregate materials where rugged construction and spill-proof/jam-proof suspension design are the most essential attribute. Teaming with Thayer Scale’s proven “Rocking Flexure” fulcrum is a completely new “pipestem” single idler suspension system incorporating built-in storage means for its calibration weight (no test chains required). This combination of unique elements provides important advantages for neglected-maintenance operations where on-going dust build-up and spilled aggregates are known to foul conventional suspension designs. Applications include troughed belt conveyors of 14-48″ widths (Series 1RF-3A for 14″, 18″, 24″, 30″; Series 1RF-4A for 36″, 42″, 48″) operating at speeds up to 600 fpm and inclines up to 18 degrees.

    Model “RF” BELT SCALE CONFIGURATION There are two basic weighbridge configurations -approach and approach-retreat. The selection depends on a number of factors. Among them are space available, belt loading, idler spacing, belt tension, required accuracy and frequency of calibration. APPROACH TYPE: An approach weigh bridge is suitable for most applications requiring an accuracy of 1/4% to 1% of full scale. It is available in one, two and three-idler designs.

    APPROACH-RETREAT TYPE: The approach retreat weighbridge is designed principally for high accuracy applications normally requiring certification for commercial weighing and accuracy as high as 1/10%… available in four and six idler designs.

    The scale provides for complete mass counterbalancing of the dead load (idlers and belt) of the conveyor permitting the load sensor to react only to the net material load. This unique system is not affected by dirt, shocks or vibration, and can withstand overloads in excess of 1,000% of rated capacity without causing damage or affecting calibration. The highly advanced and extremely robust sensing technology is based on the marriage of the weight transducer, embedded temperature sensing and proprietary linearization and temperature compensating algorithms.