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SFT Weighing Technology

Coperion K-Tron Smart Force Transducer technology delivers high-precision weighing, even in difficult plant environments

Accurate feeding, batching and metering of bulk solids begins with precision weighing

Coperion K-Tron pioneered vibrating wire technology for the process industries, and today continues its leadership with the Smart Force Transducer II and III. The K-SFT-II/III represent the leading edge of process weighing technology and form a solid foundation for the continuing evolution of the art and science of weighing.

In 1976 Coperion K-Tron introduced the process industry‘s first truly digital load cell. After three decades and five generations of innovation and development, Coperion K-Tron‘s Smart Force Transducer technology continues to set the standard for the industry. Advanced single-wire design, high resolution, internal force reduction, and 90% fewer parts combine to provide the highest possible levels of performance and reliability.

Experience has shown that the vibrating wire load cell is ideal for continuous weigh-feeding applications. It has proven to be flexible, reliable, accurate, linear, and cost effective. Measurement is truly continuous, and SFT resolution is over 1:4'000'000 in 80 ms. It is not a coincidence that all leading weigh-feeder manufacturers throughout the world today now employ some version of the vibrating wire load cell Coperion K-Tron pioneered in the mid 1970s.

Coperion K-Tron's SFT weighing technology is at the heart of our range of highly accurate gravimetric feeders.

Benefits & Features

  • 100% digital design, no calibration required
  • Advanced single wire weighing technology
  • Resolution of 1:4'000'000 in 80 ms
  • Weight captured, linearized and temperature compensated 112 times per second
  • Zero data loss measurement
  • Digital low-pass filter reduces effect of plant vibration
  • Stand-alone RS485 network connected for multiple load cell systems
  • On-board microcontroller, custom frequency processor, calibration memory and voltage regulator
  • Hazardous area models available for European (ATEX) and North American (NEC) standards

The Technology Behind SFT

Vibrating Wire Technology

The relationship between a wire’s tension and its resonant frequency has been understood for a long time. With the advent of electronics, it became obvious that a vibrating wire could be used as a variable oscillator or force sensor. Today it is used in high-performance all-digital weighing scales. In such a system, the force to be measured will directly govern the tension of the wire, and the frequency of vibration will be detected and evaluated to obtain the result.

The SFT weighing module takes advantage of the dependency of a vibrating wire's resonant frequency on its tension to measure applied load. The applied load is transmitted to the wire by mechanical means, causing a change in the resonant frequency from which the value of the applied load is computed by the onboard microprocessor. A fully calibrated (linearized, spanned and temperature compensated) signal is transmitted via RS 485 serial communication to the controller.

Vibration Immune Weighing

Achieving high gravimetric feeding performance on the process line requires discriminating between weight data and the contaminating effects of inertial forces induced from ambient vibration and shock. Coperion K-Tron’s exclusive dynamic digital filtering algorithm continuously identifies and extracts spurious inertial components from the weight measurement, even in severe process environments.

SFT Weighing systems for loss-in-weight feeders

Coperion K-Tron twin screw feeder on a D5 platform scale

Smart Force Transducer (SFT) technology is integrated into our platform scales: SFS scales for small applications and D5 scales for larger applications.  Platform scales are convenient for small and mid-sized loss-in-weight feeder applications.  Installation and cleaning is easy and feeders can even be switched out using the same scale.  Gross weighing capacity is max. 200 kg depending on the configuration.

Download the Product Specification Sheets

Coperion K-Tron twin screw feeder suspended on three K-SFT-II-M load cells

Two sizes of K-SFT-II load cells are employed in all Coperion K-Tron’s three-point suspension scale loss-in-weight feeding systems.  Three-point weighing systems are ideal for larger loss-in-weight feeders. Gross weighing capacity is max. 3000 kg depending on the configuration.

Download the Product Specification Sheets

The K-SFT-III load cell is specially designed for use in single-point weighing applications, such as in the Coperion K-Tron K4G continuous gravimetric blending stations and Smart Weigh Belt (SWB) feeders.  The smaller footprint of the K4G single-point weighing system allows up to six feeders to be grouped around a process inlet providing a cost-effective, compact solution. Gross weighing capacity is max. 100 kg depending on the configuration.

Download the Product Specification Sheets

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Coperion K-Tron Smart Force Transducer technology delivers high-precision weighing, even in difficult plant environments

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