TPT July 2007

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Technology Update
30 July /August 2007
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
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
The compact WMS:
weigh, measure and stencil OCTG pipe
› 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
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 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:
› Figure 3: The compact WMS is typically configured in this layout, with
associated coating and pipe handling equipment