gravimetric-dosing-feeders

Gravimetric dosing feeders

gravimetric-dosing-feeders

Advanced technique
Gravimetric feeders basically consist of a positive-flow dry solids feeding / hoppering mechanism, or a positive displacement liquid pump as an integral part of a precision weighing system.
Here the rate of product discharging out of the feeding mechanism is precisely controlled on a weight-loss basis by an advanced multiprocessor controller.
Performance-proven in thousands of installations throughout the world, and with a history of near-zero maintenance requirements, these technologically advanced weighing mechanisms provide users with complete operational dependability.


Weight-Loss principle 
Gravimetric feeders operate strictly on the basis of the loss of a specific amount of weight (product) in a specific amount of time. There are no other factors that enter the equation. Such weigh feeders do not utilize a ‘zero reference’ as the basis for feed rate calibration; they operate strictly on the basis of ‘weight-loss’ over time.
The ‘Weight-Loss’ principle of operation offers a very precise and highly dependable method for continuous metering by weight, assuming that the weigh feeder encompasses a proven, totally viable weighing system, a reliable and versatile dry solids or liquid metering mechanism, and a control system that incorporates all of the latest technologies and algorithms for optimization of performance.
 
Weigh feeder = Volumetric feeder + dynamic weigh scale + controls
Principle of operation gravimetric weigh feeders:
  • Appropriate Metering / Mechanism-Scale-mounted
  • Product discharge controlled and based on the feed rate selection
  • When feeders supply hopper reaches a low level, it is refilled, usually automatically
Weight-Loss principle
Gravimetric model 170 feeder series
Advantages of gravimetric feeding
  • Short and long term metering accuracy
  • Operational information
  • Process automation
  • Conservation of raw materials
  • Reduce product waste
  • Improve quality of end product

Unique weighing system
Weight-Loss Weigh Feeders feature a unique weighing system specifically designed for weight-loss applications in the industrial environment. Their reliability, durability and digital weight-sensing precision are unmatched in the industry.

The weigh mechanism is unique because it uses a Ratiometric Digital Weight Resolver (RDWR) instead of a load cell. The RDWR weigh processor provides a pure, fully unamplified and accurate signal in the form of a count ranging from 0 to 1,048,576. Mechanical counterbalancing of the scale means that this pure, unamplified scale resolution is only used for the weighed product in the system.

  • 2 Scale types: Overhead and Platform.
    Selection based on application parameters
  • Weighing systems are lever mechanisms.
    Utilize stainless steel flexures for all pivotal connections
  • Lever mechanism moves as weight is added/subtracted.
    Movement is sensed by weight resolver.
  • Weight Resolver is a displacement sensor
    - does not physically contact lever mechanism
  • Weight Resolver cannot be damaged by scale shock or overload
  • Weighing mechanism is counterbalanced
    - only the “net weight” of product is weighed
  • Provides exceptionally high resolution
  • Extremely durable. Very long life. Calibration and adjustment-free
  • Ambient temperature range -20° to 60° C
  • All weigh feeders are equipped with an ACRI-LOK. Even if the
    weigh signal is distorted this system will provide a correct dosing
  • Entire weighing system unconditionally guaranteed for 5 years

 

Weighing principle 

           Overhead weighing                Platform weighing

 

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“In-Line” Weigh Feeder type 270
Model 270 Weigh Feeder has been specifically designed to accurately and reliably meter a wide variety of generally free-flowing dry solid materials, in a vertical 'in-line' configuration, at moderate to high feed rates.
 

The Model 270 Series of “In-Line” Weigh Feeders include an integral pre-feeder to feed dry solid ingredients into a “scale-mounted” circular weigh chamber, housing a series of “weigh pockets”, rotating at constant speed.
The feed output of the pre-feeder is continuously modulated so that product discharging from the weigh feeder precisely matches the feed rate selection.
And like all Weigh Feeders, the control system encompasses the latest technologies and algorithms to ensure optimum performance and accuracy.
“In-Line” Weigh Feeder type 270


Specific features

  • Metering Accuracy, accurate metering of amorphous dry solids in an “in-line” vertical configuration ± 0.25% -1% feed rate error
  • Continuous weigh feeding
    using dynamic scale, not an inferential device
  • Compact design,
    small footprint, minimal height requirements, requires less “installed space”
  • Ultra high resolution,
    mechanically counterbalanced non load cell scale counter-balanced,
  • Weigh feeder designed with only one moving part
  • Low power consumption
  • Very low noise in operation
  • Low speed unit minimising product degradation
  • Superior weight sensing and reliable long-term operation
  • Provides total product confinement
  • Dust-tight from inlet to outlet
  • Product contact parts constructed of 304 stainless steel
  • Product temperature rated to 115°C
  • Feed rate capacity up to 155 m³/hr
  • Quick-disconnect construction (option)
  • Sanitary construction to satisfy FDA/USDA requirements
  • High temperature construction (option)
Download folder weigh feeder Model 270 - Download folder weigh feeder 270 >>

 

Feeder controllers

 

The desired flow rate can be completely controlled with a wide variety of advanced control units including digital weigh processor and feedback control system. The feeder control units can be operated as an individual stand-alone device, or can be operated under the control of a remote master or DCS systems. From their unique operating software and graphics touch screens, to the latest in interfacing capabilities, these controllers offer users cutting edge technologies for optimum weigh feeder performance.

MD-II-2000 multiprocessor controller
  • Weigh feeder / motor controllers
    The entry level 702 series controller is suitable for either batch or continuous single feeder duty
  • MD-II-2000 multiprocessor controller
    The MD-II 2000 CTS series multiprocessor controller is the most popular for single feeders. It has a colour touch screen (CTS) that displays process information in a clear graphical form.
  • SBC-2000 single-feeder controller
    The SBC-2000 Single Board Controller is a compact unit in which all controls information is stored on one card. It enables serial communication with an auxiliary destination (eg pc, plc).
  • SBC-2000 multi-feeder controller
    All controllers are now available with integral Ethernet network gateway and Fieldbus modules, so they can interface with a LAN or other host device such as a plc or dcs.
    The Personal KDU is designed to communicate with up to 32 feeders via a remote infra-red link, through a serial cable or via blue-tooth.The MD-II MFC multi-feeder controller can control up to 32 feeders in different combinations of systems.
  • LCS-2000 feeder mounted controls

Weigh feeder C-702 series controller SBC-2000 single or multi feeder controller Personal KDU controller

 

 

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