TPT March 2007

I nspection, M easuring, T esting & M arking

Weigh measure stencil (WMS) system from identification specialists

Tube manufacturers need to accurately weigh, measure, record and tally tube weights and lengths for their own records, and to stencil and stamp these tubes with order information. These markings provide identification and traceability. In the past, measuring and marking systems for tubes were typically manual operations, leading to inevitably frequent errors. The current application of the Weigh Measure Stencil (WMS) system, from Infosight, offers a number of minimum automatic capabilities. These include weight and length measurement, stenciling, and report generation. In addition, optional automatic capabilities are possible and include stamping and colour banding. The inline version of the WMS system typically makes use of the user’s existing tube conveyors to move the tube during length measurement and stenciling. A typical inline plan layout is shown in figure 2. Typically, weighing of a static tube is performed at an upstream weigh scale. The captured weight is then stored in the WMS system memory. Using the inline WMS system, length measurement is performed as the tube moves through the conveyor. An encoder roller used in combination with a number of sensors measures the tube length on-the-

fly. Length accuracy is typically guaranteed at API (American Petroleum Institute) tolerance of (30mm or 0.1ft). The captured length value is stored in the WMS system memory. The system performs a tolerance check of weight to length by comparing the actual weight to the actual length and by memorizing the theoretical weight per foot. If the comparison falls outside of

allowed tolerances, the tube is automatically marked as a reject. A length range check is also performed, to confirm the tube length falls within a programmable min/max length range. After a tolerance and length range check, the good or reject message is ‘compiled’ by combining the weight, length, and stencil data into one message for stenciling onto the tube. Stenciling is then performed as the tube travels in the V-roll

› Figure 3 (top) a typical cross section through walking beam WMS system, and (above) highly advanced marking technology for barcoding tube and pipe

check of weight-to-length and length range check are then performed. Following this, the message is ‘compiled’ by combining the measured weight, the measured length, and either the good or reject stencil data into a message for stenciling on the tube. Stenciling is performed by lowering a marking carriage to bear on the top of the tube with a contact roller, with a marking head then traversed longitudinally to mark the stencil message along the tube’s axis. Specialised logos such as the API logo can then be marked. Stamping is performed to mark up to 40 characters, with typical character height ranges from 6mm (0.25") to 10mm (0.4"). Dot matrix character density typically ranges from 5x7 to 7x9 (width x height). For either geometry, a printed Tally report is generated (showing totalized length and weight by shift, day and order), while a production report is also generated (showing message data printed on each pipe).

conveyor. The tube approaches the stencil jib and sensors detect the tube’s passage. The stencil jib lowers the marking head, and marks the compiled message onto the tube. The marking head rises upon completion of marking.

fi Figure 2 (below) a typical in-line WMS plan layout, and figure 1 (bottom) a cross transfer walking beam WMS system

On the second system version – the cross transfer WMS system – length measurement is performed on the tube in a set of idle rollers. The tube is pushed along by a pusher cylinder and the length is measured by an encoder roller and an array of sensors. Length accuracy is typically guaranteed at a tolerance of 10mm or 0.4". The captured length is stored in the system memory. Weighing of a static tube is performed on a weighbridge supported on load cells, with the weight stored in system memory. A tolerance

InfoSight Corporation – USA Fax : +1 740 642 3777 Email : sales@infosight.com Website : www.infosight.com

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M arch /A pril 2007