TPT July 2007

Technology Update

per unit length testing is accomplished, and the pipe is stenciled with its particulars. Since the leading end of the pipe was already registered in the length capture station, the stenciling head is immediately moved to this point (plus a programmable offset), where it is lowered and the stencil applied. In organising all this activity, the WMS supervisory computer will consequently hold all details regarding the processed pipe. This pipe data includes the weight, length and message stenciled, along with any number of other details (grade, OD, wall, Wt/Ft, order numbers etc). This data can be added to a local tally and made available to the business database.

The compact WMS: weigh, measure and stencil OCTG pipe

For OCTG pipe producers and finishers, WMS technology (weigh, measure and stencil) is invaluable to the production and storage of individual pipe identity and tally information. Modern WMS systems also include extensions to update business databases with pipe information as pipes are processed. Technology & Services Inc, USA, has been producing such systems since 1990. The core technologies involved are weighing, length measurement, and stenciling of pipe identity onto the pipe surface. The compact WMS puts all of these functions into a roll- down table ‘plug-in’. The goal of a properly integrated WMS is to rapidly process each individual pipe introduced with total accuracy. T&S is now also able to offer a roll-down scale for capturing pipe weight in motion, as it rolls down across a short table section. This development has made it possible to fit all the components of a WMS into a conventional table as small as 8ft. In this concept, the processing of each pipe in a particular batch is handled automatically. This is undertaken via a WMS supervisory computer (providing HMI and connectivity to other systems) and a local programmable logic controller (PLC

– routine pipe handling functions). A single overhead beam spans the pipe processing area, with axes supporting length capture and stenciling operations. This beam is sized to allow pipe to pass underneath, with an end mounting arrangement. Pipes are introduced into the system from the right, one at a time. This is undertaken by a conveyor kick mechanism for conveyor-fed systems, or by a pipe selector in roll-down systems. A set of pipes stops in conjunction with a suitable ‘V’ notch in the table installed at the length capture

station. These stops catch incoming pipe, and ensure that they are stable in the notch before measuring. The length measuring system (LMS) is then activated, and the length is quickly determined. Current API requirements require this length to be accurate to ±0.1ft (one tenth of a foot), which is achieved by

› Figure 3: The compact WMS is typically configured in this layout, with associated coating and pipe handling equipment

The compact WMS is typically placed in a layout as shown in figure 3, with associated coating and pipe handling equipment. Shown are an inbound pipe table allowing pipe to be forked onto a roll-down section feeding the compact WMS. This configuration also includes the compact WMS, a short exit table feeding a coating conveyor, induction heating for preparing the pipe surface for coating, a coating applicator, exit conveyor section, chain drive exit dry down table, and a roll down table section (for storing finished pipe). T&S can provide a compact WMS as shown in figure 3. Tubing producers usually require a different unit from producers of casing or large pipe, because the underlying structures are sized to their particular product mix. There are a variety of stencil applicators on the market. T&S offers the Taskwriter™ and Zanasi ® stencilers for air-atomized or DOD applications. The company can also supply a large range of data handling systems. Technology & Services Inc – USA Fax : +1 740 626 2025 Website : www.technologyandservices.com

the WMS length measurement system. This action is accomplished by lowering and then moving two sensors along the longitudinal axis of the pipe until the location of both ends is detected. Each axis starts from the locations registered for the last pipe inserted, so motion is limited to the variability in the batch. The length thus determined is immediately passed to the WMS supervisory computer, and retained for further processing. If a problem (ie length out of range) occurs then the system operator is notified, and methods for rapid recovery are invoked. Assuming the stencil station is clear, the pipe is then indexed out of the LMS notch and rolls across the scale. Here, the weight is captured and immediately sent to the WMS supervisory computer, where it can be tested against weight limits set for the batch. A second set of pipe stops, again in conjunction with a suitable ‘V’ notch in the table, is installed at the stenciling station. The pipe lands in this notch after crossing the scale. Here, weight

› Figure 1: Conceptual view of a compact WMS system (weigh/measure/stencil) fi Figure 2: This system is capable of processing pipe from 1.90" OD to 5" OD, handling lengths from 15-48ft, with a max weight of 1,500lbs. The Compact WMS shown can process pipe at a rate of 5 pipe per minute

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J uly /A ugust 2007