THAYER SCALE MODEL MWF WEIGH BELT FEEDER

 The MWF-101 Weigh Belt Feeder provides Thayer Scale accuracy, ruggedness and reliability and reduces measurement errors. Self cleaning pulley eliminates material build-up and belt tracking problems. Unique flared skirt design prevents material spillage and assures proper feed control. Rigid scale support system provides exceptional stability, assuring accuracy without frequent re-calibration.

Belt velocity is measured from the tail pulley, not the drive motor, providing a direct measurement of belt speed which improves both measurement and control of the material. Totally enclosed, gasketed design assures safe, dust free operation even when handling fine powder. The strain gauge load cell assembly can be easily removed then reinstalled without re-calibration of the feeder.

A standard design coupled with dimensions and rates that are tailored to each application add versatility to its capabilities. Its design for ease of maintenance and the ability to change its throughput rating gives it a long useful life in a rapidly changing industrial environment.

• Very Small Size: 25″ center line inlet-to-center line outlet for the 10″ wide belt and 41″ for the 13″ wide belt.
• Handles a wide range of materials and densities.
• Sanitary, stainless construction.
• Totally enclosed for effective dust control.
• Easy access, low maintenance design.
• Totally removable scale assembly needs no re-calibration after reinstallation.
• Excellent accuracy and stability.
• Rugged construction-built to survive.

Thayer Scale’s Model MWF is a widely recognized general purpose low capacity weigh belt feeder designed to operate accurately and reliably in harsh industrial environments with minimal maintenance. It can be used with an open loop belt drive to gravimetrically measure the flow of material, or with closed loop control to operate as a feeder and regulate the flow to a constant or dynamic set point.

A standard design coupled with dimensions and ratings that are tailored to each application add versatility to its capabilities. Its design for ease of maintenance and change of its ratings gives it a long useful life in a rapidly changing industrial environment.

When connected to the THAYER family of instrumentation it can be consistently and accurately calibrated and the measurements can be presented to operators and supervisory controls seamlessly through a variety of standard industrial interfaces. The instrument can control the flow of material as a master feeder or as a slave proportioning its feed rate to some other master signal.

The Thayer Model MSF is designed for fast, easy and thorough clean out. Feeder completely disassembles without tools in less than one minute. High quality, rugged, stainless steel construction assures years of reliable, trouble free operation even in the most severe industrial environments. The unique combination of vertical-wall supply hopper, preconditioning trough/chamber containing a special horizontal agitator (optional), accounts for the Model MSF superior performance and reliability.

An important factor in achieving high accuracy using volumetric screw feeders is consistent material bulk density. This can be achieved by a properly designed and selection agitator located in the conditioning zone of the feeder trough. The agitator de-aerates the material to a uniform density and breaks any bridges or rat holes. This combination with a wide section of agitator designs allows a greater cross-section of materials to be fed very accurately.

Volumetric Capacity:
Up to 23 ft3/hr (0.65 m3/hr) at a material bulk density of 50 lb/ft3 (0.8 gr/cm3). Consult factory for higher feed rates.

Screw Sizes:
Range from 3/8″ Ø. (variable pitch) to 2.0″ Ø (variable pitch) open helix.

Hopper Capacity:
Hoppers available as an extension of the feed trough, 0.50 Ft3 hopper expandable to 2.0 Ft3. For larger hopper sizes consult factory.

Feeder Drive:
0.5 HP, AC, Inverter Duty, TEFC, 230 or 460 VAC.

Trough Agitator:
Independently driven, constant speed, horizontal mount with 0.25 HP, AC motor 230 or 460) . Continuously conditions material to aid in de-aeration & maintain a uniform bulk density.

Material Contact Surface:
2B Mill Finish (material contact parts), 304 and 316 Stainless Steel, other finishes available.

Non-Material Contact Surfaces:
Carbon steel painted with primer and industrial grade enamel paint (special coatings and stainless steel available upon request).

Temperature Range: Material:
32°F (0°C) to 130°F (55°C) standard. Consult factory for other temperatures.

Accuracy:
1.0% to 2.0% of set rate ±2 sigma based on thirty consecutive, 1 minute samples.

S52c WEIGH BELT or LOSS-IN-WEIGHT CONTROLLER

The S52c Instrument can be used on most Weigh Belt and Loss-In-Weight Feeder systems to provide continuous control and information about the flow of material to its process by monitoring the load and speed. The weigh system can use either a strain gage or LVDT Load Cell to sense weight; however a variety of sensors can be used to sense the speed.

Weight information on a Weight information is processed as weight per length and speed is processed as unit length per time. Integrated together, this information is processed by the controller portion of the instrument to provide continuous control of the system to match a target flow rate or set-point.

On a Loss-In-Weight application the S52c uses the change in weight of the feeder to determine instantaneous material flow rate and accumulative weight total information. The speed is used to control the feeder when in volumetric control, used during refill and disturbance control integrated together, this information is processed by the controller portion of the instrument to provide continuous control of the system to match a target flow rate or set-point.

All information gathered by the system is then presented both visually on the instrument’s face and through optional communications via a number of field buses.

Thayer Scale Loss-In-Weight Feeders are designed to provide precision class accuracy and repeatability even in the harshest of industrial environments. They range in capacity from grams per minute to tons per hour.

These are the most versatile feeders in the industry. At the heart of each Loss-In-Weight Feeder is a THAYER scale that has been designed exclusively for the stringent requirements of Loss-In-Weight feeding.

Thayer Scale offers a powerful set of proprietary add-on accessories that are designed to defeat the problematic flow issues encountered by industry such as bridging, flushing, adhesion and cohesion. Comprehensive process solutions that can only come from a company with over sixty years of experience.

The LWF-SG-V “Spiralator” Loss-In-Weight Vibratory Feeder is designed to operate over a very wide operating range (typically 100:1), while assuring uniform, non-pulsating flow of difficult-to discharge materials, whether they be fine cohesive powders or fragile interlocking particles of irregular shape. A slowly rotating (typically 2 rpm), non-agitating, conical wire-spiral within the hopper counteracts the material’s tendency to pack under its own weight by virtue of its “lifting” action throughout the stored material. The resulting reduction in consolidation pressures throughout the material mass assures that the stored material will not develop sufficient strength to form stable arches that can cause erratic flow or complete flow stoppage. The combination of this unique material conditioning system and a vibrating pan feeder assures that the material will be handled reliably and gently throughout the entire feeding range.

Weight Measurement System

The heart of any gravimetric feeder is its scale system. The LWF-SG10- V incorporates a unique flexure suspension scale designed exclusively for use on Loss-In-Weight Feeders:

• High efficiency “dead load” counterbalancing
• Non-tilting platform design
• Tolerant of shocks and overloads
• Mechanical force “summing” to a single load sensor
• Full range sensor utilization = maximized resolution
• Low mechanical resonance frequency

SG-10 FMSS SCALE

Flexure plate system eliminates all wearing parts, such as bearings, pivots and knife edges and is not susceptible to vibration. Flexure suspension system transfers all loading forces to a single load transducer, which accurately measures load regardless of load position. Most platform scales are not designed to be immune to side loading and/or tortional loading caused by the plant environment and by the movement of the feed screw, agitator, etc. These factors can cause poor accuracy and poor calibration stability. Thayer’s flexure system cancels all horizontal force vectors and also allows heavy tare loads (weight of feeder and hopper) to be completely mass counterbalanced , permitting load cell sizing based on net rather than gross weight.

• Accurately measures load regardless of load position.
• Immune to support structure deflections and process vibrations.
• Inherently self aligning to gravity.
• Nulls out heavy tare loads.
• 1,000% over load capacity.
• Scale may be suspended from above or supported below.
• Immune to shock or impact loads.
• Easily accessible load cell can be accessed without removing the feeder.

Thayer Scale Loss-In-Weight Feeders are designed to provide precision class accuracy and repeat-ability even in the harshest of industrial environments. They range in capacity from grams per minute to tons per hour.

These are the most versatile feeders in the industry. At the heart of each Loss-In-Weight Feeder is a THAYER scale that has been designed exclusively for the stringent requirements of Loss-In-Weight feeding.

Thayer Scale offers a powerful set of proprietary add-on accessories that are designed to defeat the problematic flow issues encountered by industry such as bridging, flushing, adhesion and cohesion. Comprehensive process solutions that can only come from a company with over sixty years of experience.

Thayer Scale’s Model LWF-SG-TS Twin Screw Loss-In-Weight Feeder is designed to reliably and accurately meter cohesive, easily aerated and difficult to control powders.

Deep Tear-Drop “U” trough screw feeder with horizontal agitator that moves material away from both front and back walls of the conditioning chamber above. The deepness of the trough assures that the screw is completely submerged in “quiet” material, free of the usual surface disturbances arising from the turning agitator above. This, along with an inherently larger trough “wrap-around” angle, provides for complete and efficient filling of each individual flight. This helps to maintain a more uniform material density throughout. Another advantage of the deep-trough design is that it is less susceptible to transient overfeeding that accompanies hopper refilling.

Fast and easy to clean.

The LWF-SG10-TS is designed for fast, easy and thorough clean out. Feeder completely disassembles in less than one minute. High quality, rugged, stainless steel construction assures years of reliable, trouble free operation even in the most severe industrial environments.

Weight Measurement System

The heart of any gravimetric feeder is its scale system. The LWF-SG10-TS incorporates a unique flexure suspension scale designed exclusively for use on Loss-In-Weight Feeders:

• High efficiency “dead load” counterbalancing
• Non-tilting platform design
• Tolerant of shocks and overloads
• Mechanical force “summing” to a single load sensor
• Full range sensor utilization = maximized resolution
• Low mechanical resonance frequency

Flexure plate system eliminates all wearing parts, such as bearings, pivots and knife edges and is not susceptible to vibration. Flexure suspension system transfers all loading forces to a single load transducer, which accurately measures load regardless of load position. Most platform scales are not designed to be immune to side loading and/or tortional loading caused by the plant environment and by the movement of the feed screw, agitator, etc. These factors can cause poor accuracy and poor calibration stability. Thayer’s flexure system cancels all horizontal force vectors and also allows heavy tare loads (weight of feeder and hopper) to be completely mass counterbalanced , permitting load cell sizing based on net rather than gross weight.

• Accurately measures load regardless of load position.
• Immune to support structure deflections and process vibrations.
• Inherently self aligning to gravity.
• Nulls out heavy tare loads.
• 1,000% over load capacity.
• Scale may be suspended from above or supported below.
• Immune to shock or impact loads.
• Easily accessible load cell can be accessed without removing the feeder.

Thayer’s Bridge Breaker™ is designed to move hard to handle material which have a tendency to bridge, rate-hole or otherwise obstruct free flow through a silo, bin, hopper or chute. The Bridge Breaker™ is constructed from either expanded metal or bars screens, designed to individual bin configurations. The screens are internally mounted, parallel to the bin walls. An externally  mounted vibrator, transmits a rapid vibrating action to the screens by means of bolts that pass through the bin wall. The bolts pass through vibration mounts permitting the Bridge Breaker™ screen to vibrate freely with respect to the bin and other stationary equipment.

The screen is placed within the bin at critical points where bridging or arching might occur. When this happens, operation of the Bridge Breaker™ screen undercuts the bridge of material to fall to the discharge point of the bin. By continuously operating the Bridge Breaker™ during discharge operation, bridges are prevented from forming thereby maintaining a continuous material flow.

In as much as the motion of the vibrating screen is always parallel with the sides of the bin, the vibration does not tend to compact the material as is often the case with bin wall mounted vibrators. The screen sections are adaptable to either flat or conical surfaces and are specifically designed for your application.

Bridge Breakers are suitable for operation with hard to handle materials such as titanium dioxide, clays, pigments and a multitude of varying handling characteristics. Bridge Breaker™ screen assemblies can be provided for areas up to four square feet depending on the type of material and bin configuration. As many Bridge Breakers as desired can be mounted within a bin. However, in most instances only a few Bridge Breakers will do the job when mounted at the critical points.

MATERIALS HANDLED with BRIDGE BREAKERS™

WHOLE CORN, IRON OXIDE, MALT, GYPSUM, GRAIN, LIME, PLASTIC RESIN, TOBACCO, SPENT GRAIN, FIBER GLASS, SODIUM SILICATE, SOAP POWDER, SULPHUR, DRIED BONE MEAL, ZEOLITE, DRIED ONIONS, FIRE CLAY, GROUND MALT, WET CORN FIBER, PET FOOD, ADIPIC ACID, CERAMIC MIX, CHINA CLAY, POLYPROPYLENE, CALCIUM CARBONATE, CLAY, VEGETABLES, FLOUR, STARCH, SODA ASH, OATS, PEANUTS, FIBERGLASS, BIOMASS, CEMENT, PROTEIN POWDER, FOUNDRY SAND, POWDERED CHOCOLATE, LIME DUST, ANIMAL PROTEIN, SUPER PHOSPHATE, RYE MEAL, PTFE, IRON PYRITES, DRY TABLE SALT, POTATO STARCH, CUPROUS OXIDE, GROUND ALUMINA, POTASH, PET FOOD, AMMONIUM NITRATE PRILLS, GRAPHITE, PLASTIC POWDER, SODIUM BICARBONATE, IRON OXIDE, PVC REGRIND, ALUMINUM POWDER, WOOD CHIPS, RESIN, SAW DUST, SILICA, WOLLASTONITE, ZINC STEARATE, SUGAR, RUBBER, FLOUR, ACTIVATED CARBON MILK POWDER, DIATOMACEOUS EARTH, INSTANT COFFEE, CHALK, SUGAR, CARBON DUST, MELAMINE, CARBOXY METHYL CELLULOSE, CELLULOSE POWDER

Superior Performance in an economical package

The THAYER models 2LLRF-4A Belt Scale is designed for high accuracy (1/4% typical) inventory control and totalization of applications where the lb/ft loading on the conveyor is lower than 10 lb/ft. . The weighbridge features exclusive rocking flexure suspension in the approach configuration. Measurement sensitivity is high, deflection is low, and the load cell is isolated from the error-inducing effects of extraneous lateral forces, offcenter loading, foundation distortion, inclination hold-back forces, and high sporadic shocks and overloads. Tare load is mass counterbalanced to create superior signal to noise ratio in weight sensing, orders of magnitude better than belt scale designs supporting full tare load on the load sensor.

THAYER Load Cell Utilization Factor

The distinct specification of continuous belt scale weighing applications and the unique environment and operational issues those applications typically encounter, places too many requirements on the load sensing system for any single technology to completely satisfy. Therefore, using THAYER’S exclusive FMSS technology in the design of its belt scale suspension system allows the choice of using either its LC‐137 LVDT Load Cell or its LC‐ 174 Strain Gauge Load cell. This puts Thayer in a unique position that allows us to offer equipment to match a wide range of applications such as light material loading, severe environmental conditions, and commercial certification.

THAYER WEIGHT SENSING SYSTEM
Thayer’s 2LLRF-4A Belt Scale Weigh Bridge is a rugged design that accurately measures the material weight in extreme environmental conditions without constant maintenance and attention. The weighbridge is a three-point suspension frame that incorporates a unique rocking-flexure fulcrum that is totally unaffected by vibration and dust build-up.

Among the significant features of the THAYER Weight Sensing system are:

• No wearing parts
• One load cell
• Rugged tubular steel frame
• No flat surfaces for material build up
• Low deflection through secondary lever
• All stainless steel hardware
• LVDT or Strain Gauge Load Cell

THAYER’S RF Flexure Suspension (patented)
The axis position is permanent, being held in its horizontal position by the flexure plate and in its vertical position by the load rod which bears on the flexure plate, which in turn is bolted to the bottom side of the square and elevated suspension extension shaft.

There is insignificant rotational hysteresis. While the load rod may be likened to a dull knife edge (it is round), the flexure plate bearing surface directly in contact can rock without sliding through small rotational displacement.

The reaction to lateral forces creates an insignificant moment transfer to the weigh suspension (this is part of the patent). Since the flexure plate (which is hardened blue tempered steel) is also the upper bearing block of the pivot, tensile or compressive forces reacting to lateral forces therein have no moment arm distance to operate

CALIBRATION
A belt scale should be thought of as a precision instrument and its performance should be quickly and easily checked. Thayer Scale can provide an accurate reliable calibration using a certified calibration weight instead of test chains or electronic simulation of load, for all scale capacities. Thayer Scale developed and patented the first automatic calibration system for conveyor belt scales in 1971.

For belt scale calibration, Thayer Scale utilizes the test weight which represents a specific pound per ft loading value and an automatic belt length measurement system. This combination produces accurate, repeatable calibrations free from human error. Unlike electronic calibration which simply simulates a load cell output to the instrumentation, the test weight mechanically exercises the scale mechanism. Thayer’s unique suspension design assures that the test weight will accurately load the scale and will weigh a maximum of approximately 60 lb (typically much lighter) while still representing 80-100% of full scale load. Calibration time is reduced to a matter of minutes and can be performed by one person.

Key advantages:

• Test Weight more manageable. One man operation.
• Loading effect independent of conveyor incline.
• Longitudinal restraining elements not falsely loaded

Precision Belt Speed Measurement
Accurate belt speed measurement requires the use of a precision wheel and pulser. A spring is used to maintain proper contact pressure of the wheel with the tension side of the belt in all operating conditions. The THAYER belt travel pulser assembly includes a precision cast/machined wheel with a “pre-calibrated” circumferential tolerance of ± 0.05% and a high resolution digital transmitter. The transmitter produces pulses equivalent to 1/100 to 1/200 of a foot of belt travel. The speed pick-up wheel has a narrow face width so it is less susceptible to material build-up, which can result in speed measuring errors. Since belt stretch is not constant throughout the length of the conveyor, and therefore, can affect speed measurement, the speed pickup produces a more accurate speed signal than that which is produced by tail pulley mounted speed encoders.

The “Quarry King” suspension system is fabricated from slim flat metal elements (carbon steel standard, stainless steel optional) which are precision laser cut from sheet stock and welded to, and branch outwardly from, a centrally positioned tubular “spine” shaft running axially to the conveyor and directly under the center line of the belting. These elements, two of which support the weigh idler, lie in a vertical plane so as to eliminate tare build up areas. There are no structural elements running parallel to and in close proximity with the conveyor side stringers as in conventional designs to trap and hold aggregate material spilling from the edge of the belting.

For 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 attributes. Working in combination with Thayer Scale’s proven “Rocking Flexure” fulcrums 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″ belt widths (Series 1RF-3A for 14″, 18″, 24″, 30″; Series 1RF-4A for 36″, 42″, 48″ belt widths) operating at speeds up to 600 fpm and inclines up to 18 degrees.

The suspension system is longitudinally restrained and pivoted at the in-feed (approach) end on Thayer Scale’s proprietary RF Fulcrum arrangement, while the downstream end is supported from a single NTEP certified strain gauge load cell loaded in pure tension, protected from effects of all extraneous lateral forces (belt tension, friction, torsion, etc.). A key advantage is that the load cell can be quickly and easily removed and replaced without disturbing the weigh idler itself, thereby eliminating the tedious task is re-setting and aligning the idler, and conducting another material test upon re-commissioning. The non-weighed Bridge Element that supports the load cell also includes the supporting brackets for storing the Test Weight which can be easily moved to its “calibration” position on the suspension system whenever desired.

 Precision Belt Speed Measurement
Accurate belt speed measurement requires the use of a precision wheel and pulser. A spring is used to maintain proper contact pressure of the wheel with the tension side of the belt in all operating conditions. The THAYER belt travel pulser assembly includes a precision cast/machined wheel with a “pre-calibrated” circumferential tolerance of ± 0.05% and a high resolution digital transmitter. The transmitter produces pulses equivalent to 1/100 to 1/200 of a foot of belt travel. The speed pick-up wheel has a narrow face width so it is less susceptible to material build-up, which can result in speed measuring errors. Since belt stretch is not constant throughout the length of the conveyor, and therefore, can affect speed measurement, the speed pickup produces a more accurate speed signal than that which is produced by tail pulley mounted speed encoders.

Thayer Scale’s Model MDL Weigh Belt is widely recognized mainline industrial continuous weigh belt feeders. They can be used with an open loop belt drive to gravimetrically totalize and measure the flow of material, or with closed control as a feeder and regulate the flow to a constant or varying set point.

The Model MDL bridges the gap between standard low capacity and high capacity weigh feeders. Some materials are too abrasive for standard low capacity feeders, lump sizes can be too large or flow rates slightly exceed specified limits, resulting in low accuracy and constant maintenance problems. These applications often can’t be reliably handled by larger, high capacity weigh feeders because the relatively low flow rates fall below specified limits. (for example: feeding 1.5 lumps of coal @ 2 STPH). The Model MDL is as ruggedly built as our capacity weigh feeders, to withstand abrasive materials, but is designed to operate at flow rates just beyond the limits of our low capacity feeders.

• No scale can take more abuse
• Sustained sensitivity without maintenance
• Inherently self aligning to gravity
• Nullifies heavy tare loads
• Adapts to all mounting arrangement
• Tolerates heavy overloading
• Withstands extraneous lateral shocks
• Easily accepts Automatic Test Weight Lifter
• Low Maintenance
• Versatile and Flexible

AUTOMATED TEST WEIGHT LIFTER (ATWL) for Cable Scale
More and more weigh scales are being used in conjunction with statistical process control where performance records are routinely generated and delivered with the product as required by a customer’s quality assurance program. Such a record should contain a “validation of scale calibration” step to be truly meaningful as a quality assurance tool. Thayer Scale’s Automated Test Weight Lifter (“ATWL”) provides a means for automatically applying a known test load and going through a calibration sequence on computer or push-button command to check scale calibration. A “foolproof” self-checking software algorithm in the feeder control instrumentation prevents erroneous calibration.

The test weight calibration method has proven accurate and reliable over decades of in-plant use. Unlike material sampling, it is always clean, fast and safe and free from human error. Unlike electronic signal simulation, it mechanically tests the performance of critical electro-mechanical components under the full deflection range of the load cell.

If you are presently using THAYER Weigh Feeders and/or Conveyor Belt Scales equipped with earlier generations of THAYER instrumentation (I-128, ORT-132, ORT-132A, I-133, IFC-133, PI-164, PIC-168 or EZ-3200), or gravimetric feeders and conveyor belt scales supplied by other manufacturers, then you may benefit by upgrading to this latest technology.

Instrument upgrade kits can be installed and commissioned oftentimes using existing wire and conduit runs to reduce installation costs and with minimal impact to your operations and production goals. No matter what your schedule we can work with you and your maintenance staff to minimize process downtime.

Since the S52 series and Series 5200 families of instrumentation feature many of the same calibration routines, alarm messages, menu structures, and diagnostic tools as some of the previous generations of THAYER instrumentation, learning curves for new instrumentation are substantially reduced.

THAYER SCALE supplies comprehensive, detailed upgrade packages inclusive of all necessary hardware, drawings, manuals, programming data sheets and wiring/cabling requirements.

Contact us today for a free analysis of your existing gravimetric feeder and belt scale instrumentation. Simply tell us how you want your process control equipment to work for you and we’ll show you how to get there!

A wide selection of feeders and scales are available to handle any material from granular and flaky to fine powders. The combination of Thayer designed prefeeders, material flow aids, flexure/cable scales and operating controls assures component and one source responsibility.

Features and Benefits:

• Gain-In-Weight systems
• Loss-In-weight Systems
• Continuous Weighing
• Major and Minor ingredient systems
• High accuracy load cell and scale controllers
• Recipe management and reporting

THAYER Accumulative Ingredient Batch Scales are designed to accurately weigh solids and liquid materials ranging from highly fluid powders to corrosive chemical and ores.

Typical industries served: steel, aluminum, foundry, plastics, fertilizer, chemicals, food, cement, and many more.

Standard designs available in capacities ranging from 500 lb to 10,000 lbs. and bucket sizes from 10 to 100 ft3.

The batch scales can be fed by a front end loader, installed directly under storage silos or fed by screw conveyors, screw feeders, pumps or belt conveyors.

“FMSS” CABLE SUSPENSION SYSTEM

FMSS GAIN-IN-WEIGHT OR LOSS-IN-WEIGHT BATCH SCALE

THAYER Cable Suspension System has no equal when it comes to its ability to tolerate the unintentional operator abuse that accompanies frequent equipment clean out, setup changeovers, equipment re-positioning, and mechanical repair if necessary. This patented system utilizes a series of stainless steel cables in conjunction with Torque Transfer Tubes to accurately focus a force to a tension-type (single) load cell, which is completely independent of load position. The system is adaptable to most load cells whether they are of the strain gauge or LVDT type.

Because the system utilizes only static components, there are no active elements to maintain, even under severe operating conditions. The cable suspension system is inherently self-aligning to the direction of gravity, and therefore, is not affected by building or foundation strains. It can be hung from the ceiling or mounted on wheels without concern.

• No scale can take more abuse..
• Sustained sensitivity without maintenance.
• Inherently self aligning to gravity.
• Nullifies heavy tare loads.
• Adapts to all mounting arrangement.
• Tolerates heavy overloading.
• Withstands extraneous lateral shocks.
• Easily accepts Automatic Test Weight Lifter.
• Low Maintenance.
• Versatile and Flexible.

MINOR INGREDIENT BATCH FEEDER

Multiple Minor Ingredient Gain-In-Weigh Batch System

MULTI INGREDIENT GAIN-IN-WEIGHT BATCHING SYSTEM

SINGLE OR MULTIPLE INGREDIENT GAIN-IN-WEIGHT BATCH BIN

GAIN-IN-WEIGHT BUCKET DUMP. MAJOR SINGLE INGREDIENT BATCH SCALE

THAYER WEIGHT SENSING SYSTEM

Thayer’s 1RF-4A Belt Scale Weigh Bridge is a rugged design that accurately measures the material weight in extreme environmental conditions without constant maintenance and attention. The weighbridge is a three-point suspension frame that incorporates a unique rocking-flexure fulcrum that is totally unaffected by vibration and dust build-up.

Among the significant features of the THAYER Weight Sensing system are:

• no wearing parts
• one load cell
• Rugged tubular steel frame
• No flat surfaces for material build up
• Low deflection through secondary lever
• All stainless steel hardware
• LVDT or Strain Gauge Load Cell

THAYER’S RF Flexure Suspension (patented)

The axis position is permanent, being held in its horizontal position by the flexure plate and in its vertical position by the load rod which bears on the flexure plate, which in turn is bolted to the bottom side of the square and elevated suspension extension shaft.
There is insignificant rotational hysteresis. While the load rod may be likened to a dull knife edge (it is round), the flexure plate bearing surface directly in contact can rock without sliding through small rotational displacement.
The reaction to lateral forces creates an insignificant moment transfer to the weigh suspension (this is part of the patent). Since the flexure plate (which is hardened blue tempered steel) is also the upper bearing block of the pivot, tensile or compressive forces reacting to lateral forces therein have no moment arm distance to operate

CALIBRATION

A belt scale should be thought of as a precision instrument and its performance should be quickly and easily checked. Thayer Scale can provide an accurate reliable calibration using a certified calibration weight instead of test chains or electronic simulation of load, for all scale capacities. Thayer Scale developed and patented the first automatic calibration system for conveyor belt scales in 1971.
For belt scale calibration, Thayer Scale utilizes the test weight which represents a specific pound per ft loading value and an automatic belt length measurement system. This combination produces accurate, repeatable calibrations free from human error. Unlike electronic calibration which simply simulates a load cell output to the instrumentation, the test weight mechanically exercises the scale mechanism. Thayer’s unique suspension design assures that the test weight will accurately load the scale and will weigh a maximum of approximately 60 lb (typically much lighter) while still representing 80-100% of full scale load. Calibration time is reduced to a matter of minutes and can be performed by one person.
Key advantages:

• Test Weight more manageable. One man operation.
• Loading effect independent of conveyor incline.
• Longitudinal restraining elements not falsely loaded

Precision Belt Speed Measurement

Accurate belt speed measurement requires the use of a precision wheel and pulser. A spring is used to maintain proper contact pressure of the wheel with the tension side of the belt in all operating conditions. The THAYER belt travel pulser assembly includes a precision cast/machined wheel with a “pre-calibrated” circumferential tolerance of ± 0.05% and a high resolution digital transmitter. The transmitter produces pulses equivalent to 1/100 to 1/200 of a foot of belt travel. The speed pick-up wheel has a narrow face width so it is less susceptible to material build-up, which can result in speed measuring errors. Since belt stretch is not constant throughout the length of the conveyor, and therefore, can affect speed measurement, the speed pickup produces a more accurate speed signal than that which is produced by tail pulley mounted speed encoders.

Superior Performance in an economical package

The THAYER 1RF-4A Belt Scale is designed for high accuracy (1/4% typical) inventory control and totalization. The weighbridge features exclusive rocking flexure suspension in the approach configuration. Measurement sensitivity is high, deflection is low, and the load cell is isolated from the error-inducing effects of extraneous lateral forces, off-center loading, foundation distortion, inclination hold-back forces, and high sporadic shocks and overloads. Tare load is mass counterbalanced to create superior signal to noise ratio in weight sensing, orders of magnitude better than belt scale designs supporting full tare load on the load sensor.

The post Model 1RF-4A Conveyor Belt Scale appeared first on Thayer Scale.

The THAYER NAR Belt Scales are designed to deliver exceptional stability and accuracy for use in applications requiring verifiable accuracy. They are recommended for applications requiring commercial certification for billing purposes. These Belt Scales have been proven in service demanding ±0.125% accuracy through independent certification. The weigh bridge features exclusive rocking flexure suspension in the approach-retreat configuration. Measurement sensitivity is high, deflection is low, and the load cell is isolated from the error-inducing effects of extraneous lateral forces, off-center loading, foundation distortion, inclination hold-back forces, and high sporadic shocks and overloads. Tare load is mass counterbalanced to create superior signal to noise ratio in weight sensing, orders of magnitude better than belt scale designs supporting full tare load on the load sensor.

WEIGH BRIDGE
One of the most important components of a conveyor scale system is the design of the weigh bridge itself. Regardless of the type of load cell used, a belt scale will not be able to weigh lightly loaded material and maintain its calibration for long if certain design features are not in place.

Secondary Lever
THAYER employs a secondary lever system, even though it cost more to do so, because it permits the following:

1. We can add mass (weight) to counterbalance the dead load (idler support frame, idlers, belts) and by using a secondary lever, we do not load down the suspension pivot.

2. The scale provides for complete mass counter-balancing of the dead load (idlers and belt) of the conveyor permitting the load sensor to react only to the net material load.

3. By positioning the load cell correctly, relative to the secondary lever we can match load cell size to the net loading. Only in this way can any capacity scale be supplied to the same high accuracy standards.

4. The resulting increased lever ratio of the secondary lever reduces idler deflection, providing additional immunity to errors associated with belt tension.

5. The secondary lever system utilizes stainless steel aircraft cables as flexural elements to transmit and FOCUS pure tension forces to the load cell. The cables, being non-extendable, but laterally yieldable connecting links, permit the lever to align itself under conditions of varying stringer distortion. This is a most significant feature. A belt scale must use the conveyor stringers as its mounting base. These stringers not only deflect under varying conveyor loads, but may also rotate (or twist). A suspension system having the least possible structural redundancy is therefore essential.

6. This unique system is not affected by dirt, shocks or vibration, and can withstand overloads in excess of 1,000 pounds without causing damage or affecting calibration.

THAYER’S RF Flexure Suspension (patented)
The axis position is permanent, being held in its horizontal position by the flexure plate and in its vertical position by the load rod which bears on the flexure plate, which in turn is bolted to the bottom side of the square and elevated suspension extension shaft.

There is insignificant rotational hysteresis. While the load rod may be likened to a dull knife edge (it is round), the flexure plate bearing surface directly in contact can rock without sliding through small rotational displacement.

The reaction to lateral forces creates an insignificant moment transfer to the weigh suspension (this is part of the patent). Since the flexure plate (which is hardened blue tempered steel) is also the upper bearing block of the pivot, tensile or compressive forces reacting to lateral forces therein have no moment arm distance to operate.

The Model LC-174 NTEP Certified Load Cell is a Strain Gauge “S” Beam Load Cell that is housed in an enclosure that has identical mounting dimensions to that of the LC-137.

Available in force ranges from 25 to 2,000 lbs with an overload protection of 300% of rated output.

THAYER Load Cell Utilization Factor

The distinct specification of continuous belt scale weighing applications and the unique environment and operational issues those applications typically encounter, places too many requirements on the load sensing system for any single technology to completely satisfy. Therefore, using THAYER’S exclusive FMSS technology in the design of its belt scale suspension system allows the choice of using either its LC‐137 LVDT Load Cell or its LC‐ 174 Strain Gauge Load cell. This puts Thayer in a unique position that allows us to offer equipment to match a wide range of applications such as light material loading, severe environmental conditions, and commercial certification.

CALIBRATION

A belt scale should be thought of as a precision instrument and its performance should be quickly and easily checked. Thayer Scale can provide an accurate reliable calibration using a calibrating weight instead of test chains for all scale capacities. Thayer Scale developed and patented the first automatic calibration system in 1971.

The 6RF-8AR uses a test weight in the form of a round bar which resides in one of two positions (“V” notches) on an intermediate lever between the approach suspension and the load cell itself. This bar provides tare counterbalance in its “zero” position, and simulated calibration loading in its “span” position. This method of “test weight” application is referred to as the “moveable-poise” method, in contrast to the additive weight method.

Precision Belt Speed Measurement
Accurate belt speed measurement requires the use of a precision wheel and pulser. A spring is used to maintain proper contact pressure of the wheel with the tension side of the belt in all operating conditions. The THAYER belt travel pulser assembly includes a precision cast/machined wheel with a “pre-calibrated” circumferential tolerance of ± 0.05% and a high resolution digital transmitter. The transmitter produces pulses equivalent to 1/100 to 1/200 of a foot of belt travel. The speed pick-up wheel has a narrow face width so it is less susceptible to material build-up, which can result in speed measuring errors. Since belt stretch is not constant throughout the length of the conveyor, and therefore, can affect speed measurement, the speed pickup produces a more accurate speed signal than that which is produced by tail pulley mounted speed encoders.

THAYER Belt Scale Applications Program

THAYER is the only belt scale manufacturer that analyzes the customer’s conveyor and application data to predict “real-world” performance. The computer program essentially tailors each component of the scale and conveyor to maximize the performance of the complete system based on the specific requirements of the application.

We consider the parameter variations that are normally experienced in conveyor installations, the lack of dimensional precision of the conveyor components and installation imperfections occurring as the result of both the initial set up and the subsequent conveyor maintenance activities, the most logical approach to designing and installing high accuracy belt weighing equipment is to design for minimum error influences in every phase of the project. This involves conveyor analysis work to seek out preferred locations for load and speed measurements within a conveyor, suspension system configurations that are least affected by conveyor influences, particularly alignment factors (load deflection vs installed alignment conditions), and many other factors.

The typical computer analysis involves inputting eleven (11) key parameters which describe the application in sufficient detail to estimate accuracy for the installation as initially defined.

Major factors include:
– Conveyor design,
– Scale suspension design
– Location of load and speed sensors in relation to both conveyor terminal equipment and loading points
– Installed alignment conditions
– Duration and constancy of loading cycle
– Condition of rolling conveyor elements,
– The uniformity and stiffness of the belt itself
– Condition and size of take-up apparatus
– The precision with which the system can be routinely calibrated & adherence to a calibration schedule
– Operating environment.

Subsequent runs are performed to evaluate the effects under various conditions, using different belt scale weigh bridge configurations, weigh bridge locations, idler spacing, weights and locations of gravity take-up, etc.

Actual “bias error” (offset between THAYER totalized weight and check scale weight) and “as-found error” (random error, i.e. repeatability) can be calculated for a given conveyor application using Thayer’s belt scale performance math model.

This unique program was developed by THAYER, and is based on many years of experience in the field of high accuracy continuous weighing. The objective of the program is quite simple: To provide a means of producing a high performance Belt Scale installation.

The post 6NAR-6-8 NTEP CERTIFIED Conveyor Belt Scale appeared first on Thayer Scale.

Superior Performance for Light Loading Applications

The THAYER 4RF-6ARLA Approach-Retreat  Conveyor Belt Scale was specifically designed for high accuracy (1/8% typical) inventory control and throughput totalization of light scale loading applications such as wood chips, saw dust, grain and Biomass. THAYER’S Belt Scale weigh bridge features exclusive rocking flexure suspension in the approach configuration. Measurement sensitivity is high, deflection is low, and the load cell is isolated from the error-inducing effects of extraneous lateral forces, off-center loading, foundation distortion, inclination hold-back forces, and high sporadic shocks and overloads. Tare load is mass counterbalanced to create superior signal to noise ratio in weight sensing, orders of magnitude better than belt scale designs supporting full tare load on the load sensor.

WEIGH BRIDGE
One of the most important components of a conveyor scale system is the design of the weigh bridge itself. Regardless of the type of load cell used, a belt scale will not be able to weigh lightly loaded material and maintain its calibration for long if certain design features are not in place.

Secondary Lever
THAYER employs a secondary lever system, even though it cost more to do so, because it permits the following:

1. We can add mass (weight) to counterbalance the dead load (idler support frame, idlers, belts) and by using a secondary lever, we do not load down the suspension pivot.

2. The scale provides for complete mass counter-balancing of the dead load (idlers and belt) of the conveyor permitting the load sensor to react only to the net material load.

3. By positioning the load cell correctly, relative to the secondary lever we can match load cell size to the net loading. Only in this way can any capacity scale be supplied to the same high accuracy standards.

4. The resulting increased lever ratio of the secondary lever reduces idler deflection, providing additional immunity to errors associated with belt tension.

5. The secondary lever system utilizes stainless steel aircraft cables as flexural elements to transmit and FOCUS pure tension forces to the load cell. The cables, being non-extendable, but laterally yieldable connecting links, permit the lever to align itself under conditions of varying stringer distortion. This is a most significant feature. A belt scale must use the conveyor stringers as its mounting base. These stringers not only deflect under varying conveyor loads, but may also rotate (or twist). A suspension system having the least possible structural redundancy is therefore essential.

6. This unique system is not affected by dirt, shocks or vibration, and can withstand overloads in excess of 1,000 pounds without causing damage or affecting calibration.

THAYER’S RF Flexure Suspension (patented)
The axis position is permanent, being held in its horizontal position by the flexure plate and in its vertical position by the load rod which bears on the flexure plate, which in turn is bolted to the bottom side of the square and elevated suspension extension shaft.

There is insignificant rotational hysteresis. While the load rod may be likened to a dull knife edge (it is round), the flexure plate bearing surface directly in contact can rock without sliding through small rotational displacement.

The reaction to lateral forces creates an insignificant moment transfer to the weigh suspension (this is part of the patent). Since the flexure plate (which is hardened blue tempered steel) is also the upper bearing block of the pivot, tensile or compressive forces reacting to lateral forces therein have no moment arm distance to operate.

THAYER Load Cell Utilization Factor
The distinct specification of continuous belt scale weighing applications and the unique environment and operational issues those applications typically encounter, places too many requirements on the load sensing system for any single technology to completely satisfy. Therefore, using THAYER’S exclusive FMSS technology in the design of its belt scale suspension system allows the choice of using either its LC-137 LVDT Load Cell or its LC-174 Strain Gauge Load cell. This puts Thayer in a unique position that allows us to offer equipment to match a wide range of applications such as light material loading, severe environmental conditions, and commercial certification.

The performance of a load cell and its instrumentation is specified on the basis of the load cell’s rated output. If the load cell is supporting a quantity of dead-weight (i.e. idlers, belting, suspension system) and has been further oversized to accommodate problems of overload protection, off-center conveying, shock, vibration and negative integration, then the amount of range left to do the job of weighing is only a fraction of the cell’s rated output. The percentage of the load cell’s rated output reserved for the actual job of weighing material is called the LOAD CELL UTILIZATION FACTOR.

Thayer’s “RF” Belt Scales with “FMSS” Force Measurement Suspension System mass counter balance technology assures better than 80% Load Cell Utilization.

Provides :

• Field adjustable mechanical TARE balancing of dead loads typically as high as 200 times NET loads, thereby providing the full utilization of the load cell force range.
• Reduces deflection of load receptor to a fraction of load cell deflection.
• Reduces zero shifting as a result of foundation distortion.
• Provides preferred access location of load cell for inspection or removal.
• Simplifies the application of test weights for calibration/performance verification.

THAYER TEST WEIGHT USING “SEE-SAW” SECONDARY LEVEROn high capacity scales where it is impractical to apply the test weight directly to the end of the weighbridge because of the physical size of the test weight, a special arrangement of the secondary lever is used.

In this configuration, the test weight provides tare mass counter-balance in its “storage” position on the secondary lever and a test load of known value in its “calibrate” position. By taking advantage of ratios in the secondary lever, smaller, easily manageable test weight(s) can be used to produce significantly higher loading values. This method of applying the test weight does not introduce error on inclined conveyors. Since the test weight is on the scale at all times, its moments due to the sine component remains constant regardless of the test weight’s position on the lever.

The weight is always present on the secondary lever, which also serves as a means to counterbalance dead loads and control the force range presented to the load cell. In the movable poise weight design the weight resides in either one of two locating “V” notches, but is never added or subtracted from the lever itself.

In one position, the weight serves as “counterbalancing” weight for a portion of the dead load. In the other position, the weight serves as the calibration test load. This unique method, whereby the movement of the weight alone affords the means to apply a large effective test load, is the only practical and economical system known for calibrating “heavily loaded” conveyor scales.

Precision Belt Speed Measurement
Accurate belt speed measurement requires the use of a precision wheel and pulser. A spring is used to maintain proper contact pressure of the wheel with the tension side of the belt in all operating conditions. The THAYER belt travel pulser assembly includes a precision cast/machined wheel with a “pre-calibrated” circumferential tolerance of ± 0.05% and a high resolution digital transmitter. The transmitter produces pulses equivalent to 1/100 to 1/200 of a foot of belt travel. The speed pick-up wheel has a narrow face width so it is less susceptible to material build-up, which can result in speed measuring errors. Since belt stretch is not constant throughout the length of the conveyor, and therefore, can affect speed measurement, the speed pickup produces a more accurate speed signal than that which is produced by tail pulley mounted speed encoders.

The post 4RF-6ARLA LIGHT LOADING Conveyor Belt Scale appeared first on Thayer Scale.

Superior Performance
The THAYER models 3RFS-6 & 3RFS-8 Conveyor Belt Scales are designed for high accuracy (1/4% typical) inventory control and totalization. The weighbridge features exclusive rocking flexure suspension in the approach configuration. Measurement sensitivity is high, deflection is low, and the load cell is isolated from the error-inducing effects of extraneous lateral forces, off-center loading, foundation distortion, inclination hold-back forces, and high sporadic shocks and overloads. Tare load is mass counterbalanced to create superior signal to noise ratio in weight sensing, orders of magnitude better than belt scale designs supporting full tare load on the load sensor.

WEIGH BRIDGE
One of the most important components of a conveyor scale system is the design of the weigh bridge itself. Regardless of the type of load cell used, a belt scale will not be able to weigh lightly loaded material and maintain its calibration for long if certain design features are not in place.

Secondary Lever

THAYER employs a secondary lever system, even though it cost more to do so, because it permits the following:

1. We can add mass (weight) to counterbalance the dead load (idler support frame, idlers, belts) and by using a secondary lever, we do not load down the suspension pivot.

2. The scale provides for complete mass counter-balancing of the dead load (idlers and belt) of the conveyor permitting the load sensor to react only to the net material load.

3. By positioning the load cell correctly, relative to the secondary lever we can match load cell size to the net loading. Only in this way can any capacity scale be supplied to the same high accuracy standards.

4. The resulting increased lever ratio of the secondary lever reduces idler deflection, providing additional immunity to errors associated with belt tension.

5. The secondary lever system utilizes stainless steel aircraft cables as flexural elements to transmit and FOCUS pure tension forces to the load cell. The cables, being non-extendable, but laterally yieldable connecting links, permit the lever to align itself under conditions of varying stringer distortion. This is a most significant feature. A belt scale must use the conveyor stringers as its mounting base. These stringers not only deflect under varying conveyor loads, but may also rotate (or twist). A suspension system having the least possible structural redundancy is therefore essential.

6. This unique system is not affected by dirt, shocks or vibration, and can withstand overloads in excess of 1,000 pounds without causing damage or affecting calibration.

THAYER’S RF Flexure Suspension (patented)
The axis position is permanent, being held in its horizontal position by the flexure plate and in its vertical position by the load rod which bears on the flexure plate, which in turn is bolted to the bottom side of the square and elevated suspension extension shaft.

There is insignificant rotational hysteresis. While the load rod may be likened to a dull knife edge (it is round), the flexure plate bearing surface directly in contact can rock without sliding through small rotational displacement.

The reaction to lateral forces creates an insignificant moment transfer to the weigh suspension (this is part of the patent). Since the flexure plate (which is hardened blue tempered steel) is also the upper bearing block of the pivot, tensile or compressive forces reacting to lateral forces therein have no moment arm distance to operate.

Calibration
A belt scale should be thought of as a precision instrument and its performance should be quickly and easily checked. Thayer Scale can provide an accurate reliable calibration using a calibrating weight instead of test chains for all scale capacities. Thayer Scale developed and patented the first automatic calibration system in 1971.

Calibration

Calibration Test Weight

The 3RFS-6 and 3RFS-8 use a test weight in the form of a round bar which resides in one of two positions (“V” notches) on an intermediate lever between the approach suspension and the load cell itself. This bar provides tare counterbalance in its “zero” position, and simulated calibration loading in its “span” position. This method of “test weight” application is referred to as the “moveable-poise” method, in contrast to the additive weight method.

Precision Belt Speed Measurement
Accurate belt speed measurement requires the use of a precision wheel and pulser. A spring is used to maintain proper contact pressure of the wheel with the tension side of the belt in all operating conditions. The THAYER belt travel pulser assembly includes a precision cast/machined wheel with a “pre-calibrated” circumferential tolerance of ± 0.05% and a high resolution digital transmitter. The transmitter produces pulses equivalent to 1/100 to 1/200 of a foot of belt travel. The speed pick-up wheel has a narrow face width so it is less susceptible to material build-up, which can result in speed measuring errors. Since belt stretch is not constant throughout the length of the conveyor, and therefore, can affect speed measurement, the speed pickup produces a more accurate speed signal than that which is produced by tail pulley mounted speed encoders.

THAYER Load Cell Utilization Factor

The distinct specification of continuous belt scale weighing applications and the unique environment and operational issues those applications typically encounter, places too many requirements on the load sensing system for any single technology to completely satisfy. Therefore, using THAYER’S exclusive FMSS technology in the design of its belt scale suspension system allows the choice of using either its LC‐137 LVDT Load Cell or its LC‐ 174 Strain Gauge Load cell. This puts Thayer in a unique position that allows us to offer equipment to match a wide range of applications such as light material loading, severe environmental conditions, and commercial certification.

The post 3RFS-8 Conveyor Belt Scale appeared first on Thayer Scale.

THAYER Model FP – Flat Belt Conveyor Scale – Multiple Weigh Idlers

The THAYER “FP” Conveyor Belt Scales is a unique weighing scale specifically designed to accurately weigh “low density” materials. Weighing deck typically consists of 2 to 6 flat idlers, mounted either horizontally or at an incline of up to 12 degrees, depending on material handled. It can be used in new installations or can be seamlessly integrated into an existing conveyor. Typical application include cereals, snack foods, pet foods, wood fibers, paper waste, tobacco, and textiles (bulk densities ranging from 0.5 to 25 pcf).

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Specialized Scale design assures reliable, accurate weighing.

The most important element of the FP Belt Scale is its scale system, which utilizes Thayer Scale’s “FMSS” technology (see below). The FP has a unique combination of features that make it ideal for low density belt weighing:

– High efficiency “dead Load” counterbalancing, up to 500 lbs.
– Load sensor sized to utilize its full range for “live load” only
– Calibration maintained under heavy overloading, 1,000+lb.
– Ultra-low deflection (<0.0005 in.) negates belt tension error.
– Non-tilting platform design for conveyor alignment stability.
– Provisions for built in automatic test weight.
– Easy to re-range in the field.

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“FMSS” Scale Technology

A Force Measurement Suspension System (FMSS) is the arrangement of active mechanical elements interposed between the load receptor (belt) and load cell. Properly designed, the FMSS functions as a force vector filter that permits the sum of the chosen uni-directions force components to pass through the system to the load cell while blocking all other nuisance, erroneous or destructive force vectors.

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“FMSS” FLEXURE PLATE SYSTEM

Flexure plate system eliminates all wearing parts, such as bearings, pivots and knife edges and is not susceptible to vibration. Flexure suspension system transfers all loading forces to a single load transducer, which accurately measures load regardless of load position. Most platform scales are not designed to be immune to side loading and/or tortional loading caused by the plant environment and by the movement of the feed screw, agitator, etc. These factors can cause poor accuracy and poor calibration stability. Thayer’s flexure system cancels all horizontal force vectors and also allows heavy tare loads (weight of feeder and hopper) to be completely mass counterbalanced , permitting load cell sizing based on net rather than gross weight.

 

 

 

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Thayer Scale’s new Model i340 Conveyor Belt Scale Integrator is a full featured instrument specifically designed to match with Thayer’s single idler “Quarry King” Belt Scale. It performs the same functions as an instrument costing many times more without sacrificing accuracy that is associated with THAYER weighing products. Simplicity of use has always been a very important factor in designing an instrument and the Model i340 has inherited all the time and labor saving methods THAYER has developed over the years.

The Model i340 enables easy set-up, calibration and maintenance. Its intuitive menu interface is very easy to use.  Step-by-step on-screen instructions guide the user through set up, calibration and customization of inputs and outputs.  Multiple checks and balances built into the software virtually eliminates human error.

As an added bonus, the Model i340 Integrator contains special patented software package called “Virtual Weigh Span” Technology that has been specifically designed to be used with lower cost and lower accuracy single idler belt scales.

Imperfections in conveyor belting and its supporting elements can adversely affect weighing accuracy of belt scales. Virtual Weigh Span can be programmed to adjust for variations in the belt conveyor weighing system. Advantages include, higher degrees of accuracy and calibration to account for changes in the belt or belting system over time using non-mechanical adjustments. In addition, weight measurement error producing effects, some that may not be particularly known, may be reduced.

By selecting the Virtual Weigh Span feature it creates many of the performance benefits of having a multi-idler belt scale. With more idlers and corresponding longer weigh span, a belt scale becomes less sensitive to extraneous loading variations due to such things as splice-impact shocks, gust of wind, non-uniformity of belting weight, varying belt loading effects that are due to impressed belting curvatures (lack of flatness) that tend to decay or change inconsistently under operation, idler “wobble” effects due to T.I.R. (total indicator runout), and numerous other extraneous disturbances that can cause instantaneous measurement errors.  Since a longer weigh span provides a greater degree of load averaging the scale’s response to loading changes is more gradual and its output signals used for downstream control actions (i.e. additive feeder control) exhibit slower rates of change that are more compatible with the response limits of the controlled downstream equipment.

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THAYER WEIGHT SENSING SYSTEM

Thayer’s 1RF-4A Belt Scale Weigh Bridge is a rugged design that accurately measures the material weight in extreme environmental conditions without constant maintenance and attention. The weighbridge is a three-point suspension frame that incorporates a unique rocking-flexure fulcrum that is totally unaffected by vibration and dust build-up.

THAYER’S RF Flexure Suspension (patented)

The axis position is permanent, being held in its horizontal position by the flexure plate and in its vertical position by the load rod which bears on the flexure plate, which in turn is bolted to the bottom side of the square and elevated suspension extension shaft.

There is insignificant rotational hysteresis. While the load rod may be likened to a dull knife edge (it is round), the flexure plate bearing surface directly in contact can rock without sliding through small rotational displacement.
The reaction to lateral forces creates an insignificant moment transfer to the weigh suspension (this is part of the patent). Since the flexure plate (which is hardened blue tempered steel) is also the upper bearing block of the pivot, tensile or compressive forces reacting to lateral forces therein have no moment arm distance to operate.

CALIBRATION

A belt scale should be thought of as a precision instrument and its performance should be quickly and easily checked. Thayer Scale can provide an accurate reliable calibration using a certified calibration weight instead of test chains or electronic simulation of load, for all scale capacities. Thayer Scale developed and patented the first automatic calibration system for conveyor belt scales in 1971.

For belt scale calibration, Thayer Scale utilizes the test weight which represents a specific pound per ft loading value and an automatic belt length measurement system. This combination produces accurate, repeatable calibrations free from human error. Unlike electronic calibration which simply simulates a load cell output to the instrumentation, the test weight mechanically exercises the scale mechanism. Thayer’s unique suspension design assures that the test weight will accurately load the scale and will weigh a maximum of approximately 60 lb (typically much lighter) while still representing 80-100% of full scale load. Calibration time is reduced to a matter of minutes and can be performed by one person.

Key advantages:

• Test Weight more manageable. One man operation.
• Loading effect independent of conveyor incline.
• Longitudinal restraining elements not falsely loaded

Precision Belt Speed Measurement

Accurate belt speed measurement requires the use of a precision wheel and pulser. A spring is used to maintain proper contact pressure of the wheel with the tension side of the belt in all operating conditions. The THAYER belt travel pulser assembly includes a precision cast/machined wheel with a “pre-calibrated” circumferential tolerance of ± 0.05% and a high resolution digital transmitter. The transmitter produces pulses equivalent to 1/100 to 1/200 of a foot of belt travel. The speed pick-up wheel has a narrow face width so it is less susceptible to material build-up, which can result in speed measuring errors. Since belt stretch is not constant throughout the length of the conveyor, and therefore, can affect speed measurement, the speed pickup produces a more accurate speed signal than that which is produced by tail pulley mounted speed encoders.

Superior Performance in an economical package

The THAYER 1RF-4A Belt Scale is designed for high accuracy (1/4% typical) inventory control and totalization. The weighbridge features exclusive rocking flexure suspension in the approach configuration. Measurement sensitivity is high, deflection is low, and the load cell is isolated from the error-inducing effects of extraneous lateral forces, off-center loading, foundation distortion, inclination hold-back forces, and high sporadic shocks and overloads. Tare load is mass counterbalanced to create superior signal to noise ratio in weight sensing, orders of magnitude better than belt scale designs supporting full tare load on the load sensor.

Thayer Products

• Conveyor Belt Scales
  • Standard Configuration
  • Light Loading Belt Scales
  • NTEP Approved Commercial Belt Scales
• Weigh Belts
  • Light Duty Weigh Belts
  • Heavy Duty Weigh Belts
  • Low Density / Light Loading Weigh Belts
  • Special Purpose Weigh Belts
• Loss-In-Weight Feeders
  • Screw Feeders
  • Vibratory Feeders
• Volumetric Feeders
• Material Flow Promotion
• Instrumentation
  • Power Control Assemblies

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