NDC Infrared Engineering's Fixed Paper Sensors for Basis Wieght, Consistency, and Moisture Measurement, 104TC Series


	The Gamma Sensor provides a continuous measurement of basis weight or consistency of the sheet in the forming section on a fixed point or multi-point basis in the MD and/or CD direction.


		Benefits

	Continuous indication of consistency at strategic locations on the wire Automatic closed loop control of consistency Improves formation Increases ply bond & internal bond Monitor and control vacuum and drainage Improve runability and wet-end stability


	Refine and reduce losses at grade changes Improve Press & Dryer Settings with Auto/Manual Control Optimize top former/dandy roll performance Reduce two-sidedness Quantify the effect of table changes Evaluate forming fabrics

The 104TC Fixed Point Gamma Sensor affords a simple and realistic means to monitor and control the basis weight or consistency of the sheet at many locations in the forming section. One or more sensors can be mounted before and/or after top wires, dandy rolls, multiply sheets, and gap formers depending on various paper machine configurations.

Traditionally, papermakers have positioned the "dry-line" to obtain the proper drainage on the wire. However, larger paper machines, elevated wires, steamy forming sections, and remote control room locations make dry-line monitoring difficult for operators. As top wires and additional fourdriniers are added the dry-lines can disappear altogether.

The Gamma Sensor replaces dry-line observations by providing an accurate indication of stock consistency on the wire. Changes in the forming section drainage are represented with greater accuracy and sensitivity than a visual dry-line. Additionally, the sensors output may also be used for closed loop control of refiners, head box flows, and vacuum drainage boxes.


	Features


	One-sided, compact sensor-detector Easy integration with DCS systems Exceptional long term stability Typical accuracy better than ±1% Easy installation and removal without interfering with paper machine operation


	Grade parameters stored in battery backed random access memory (RAM) Programmable security lockout Wide variety of I/O options Hardened industrial design for 24-hour operation Touchscreen interface for ease of use


	Gauging the Quality of Forming Section

Papermakers know that paper is "made on the forming section," and key paper qualities are firmly established in the wire. Increasingly, mills look to the forming section for quality improvement. Refining, headbox water, flatbox vacuum, foils and fabric must work together to produce a high quality sheet...all of the time. On-line gauging of the forming section is required.

The Gamma Sensor allows one to continuously monitor the sheet on the forming section, to ensure quality at the reel. This nucleonic sensor monitors stock consistency on the wire and allows operators to maintain tight stock consistency control. The high sensor accuracy and sensitivity permits one to keep the stock on the forming section "on target, all of the time."


	Forming section drainage profile


	Removing the "Top-Wire Blindfold"

Top wires are being installed, in growing numbers to achieve better formation. But most top-wires "blindfold" the operator, by preventing dryline observation. The Gamma Sensor is then an essential tool for controlling stock consistency, to prevent stock throw, wet-end breaks and poor formation. On many grades consistency must be maintained within a tight band, to achieve high quality and good paper machine runnability.

The Gamma Sensor is being successfully used on many paper grades; from supercalendered coated-offset to newsprint, linerboard, food-board and corrugated medium. Sensors are operating with top-wires of all major paper machine suppliers.

The Gamma Sensor has helped new top-wire users to properly set up stock and drainage conditions for each grade. Using the sensor, mills have achieved more efficient machine startups and grade changes, and smoother ongoing operation.


	Stock consistency is optimized, going into the top-wire, for high quality and improved paper machine runnability


	The Optimum Solution for All Twin-Wire Gap Formers


	The advent of Twin-Wire Gap Formers have provided the ability for a better sheet formation, less two-sidedness and higher dewatering capacity. A fixed point or traversing sensor is generally placed after the Couch roll providing machine operators a new window into the Gap Former. This is especially critical during startups, on machines making frequent grade changes and enhancing the runability of forming fabrics.


	The NDC Infrared Engineering Sensor provides operators the ability to monitor and control consistency in Twin-Gap Formers


	Improves Formation and Ply-Bond on Multiple-Headbox Machines

Multiply sheets pose difficult operating problems. Stock consistency must be just right, going into all top-wires and dandy rolls. High consistency can cause weak ply-bonding and poor formation. Low consistency will cause crushing, stock-throw, and wet-end paper machine breaks.

Machine tenders use the Gamma Sensor to ensure that stock consistency is correct for each ply. Consistency readings are especially helpful during grade changes to minimize off-grade product and maintain good paper machine runnability. The measurements also help ensure wet-end stability in the multiple forming sections.


	Gamma Sensors help to achieve ply-bonds and good formation on the outside sheets.


	Theory of Operation


		The measurement technique employed in the 104TC Series is based on the principle of Compton Photon Backscatter (commonly known as gamma backscatter). A small nucleonic isotope in the sensor emits low-energy photons, which are collimated and directed at the measured material. These photons are backscattered toward the detector in direct proportion to the mass of the measured material. A detector in a single sided sensor converts the backscatter photons to an electrical signal, which in turn is related to weight per unit area.

	Click here for technical specifications on the fixed point gamma sensor, 104TC Series

		Korins Co.,Ltd. Rm301, #24-2, Youido-Dong, Youngdungpo-Ku, Seoul, Korea Tel. : (02)780-4848 Fax.:(02)780-1244, 786-1244 sales@korins.com