Emerson Fisher Control-Disk Reference Manual

PULP & PAPER

Kruger, Inc. Newsprint Mill Uses Fisher® Control-Disk™ Valves
to Reduce Variability, Maintenance, and Downtime

RESULTS

• Reduced maintenance costs by about $3,000 per valve.

• Reduced excessive ow variability by a factor of three,
improving stability and level measurement.

• Prevented “missed samples” from the PQM Analyzer.

APPLICATION

Level, flow, and pressure control in the refiner pulp tank.

CUSTOMER

Kruger, Inc. and its newsprint mill in Trois-Rivieres, Quebec.

CHALLENGE

Pierre Gauthier, Instrumentation Supervisor at the Kruger newsprint
mill in Trois-Rivieres, Quebec, had three knife gate valves installed to
provide level control for the refiner pulp tank. Challenge #1 was to
keep the level at the set point without major pressure variability to the
storage tank. Challenge #2 was to keep the poorly-designed valves
operating without continual and costly maintenance. The knife-gate
valves provided a variety of maintenance problems, from excessive
flow variability to leakage of the seal around the gates.

The excessive flow variability and resulting pressure fluctuations
caused instability in the sampling of the pulp to the PQM analyzer. The
PQM analyzer measures the values of fiber length and freeness of the
paper sheet. (Freeness is the porosity or space left between the pulp
fibers after being sprayed from the headbox onto the wire of the paper
machine.) Sampling is important because it directly affects porosity,
tensile strength, and other factors relating to end-product quality.

The analyzer sample is time-based, and pressure variations often lead
to “bad” samples or no samples at all. Pierre said, “The problems
multiple as the valves age and demand for TMP pulp increases. When
we close the loop, we may loose the measurement and/or have less
time to stop the lines.”

Installed 15-feet above the ground, two Control-Disk™

buttery valves (like the one above) replaced leaking knife­gate valves at a newsprint mill in Quebec.

“Installing the Control-Disk
valves was easy and did not
require any piping modifications.
The characteristic and flow
performance of this butterfly valve
is similar to that of a segmented­ball. With this new Fisher product,
we avoided maintenance-costs
of about $3000 per valve and
reduced flow variability by a
factor of three.”

Pierre Gauthier, Instrumentation Supervisor
Kruger Inc.

PULP & PAPER

SOLUTION

Fortunately for Kruger, engineers within the Fisher division of Emerson
Process Management had been studying the common aws of
traditional buttery valves and developing a new, far more reliable
design. Introduced this summer, the new Control-Disk™ valve delivers
better adherence to set point and excellent throttling performance.

The Kruger mill was eager to conduct a eld trial on-site, which was
arranged and supported by the Fisher division’s Rotary Marketing team
and the local Emerson sales ofce, Laurentide Controls.

The mill installed two Control-Disk valves to replace two ten-inch gate
valves. One valve measures level control on a rener pulp tank, Line 5.
The other improved a vacuum loop on the paper machine.

Pierre explained that Lines 1 and 2 have smaller reners, but the
process is similar to that used on Lines 3, 4, and 5. “We installed a new
6-inch segmented-ball valve to control the level of the latency chest,”
he said. “Then, we compared its performance to the Control-Disk valve
installed on Line 5 — and we were very pleased with the results.”

The Fisher-patented Control-Disk valve offers the wide control range
of a segmented ball with a true Equal Percentage Characteristic.
The Control-Disk valves were installed with the same face-to-face
dimensions, provided equal or better control performance than the
segmented ball, and avoided all the chronic maintenance issues of the
gate valves they replaced.

“The Control-Disk valves have
reduced variability, maintenance,
and downtime. But, better than
that, the PQM analyzer has not
missed any samples, and that was
our primary goal. The increased
stability and reliability, based on
improved valve performance, will
lead to better quality of our end­product.”

Pierre Gauthier, Instrumentation Supervisor
Kruger Inc.

RESULT

Using historical trend data for the level, ow, and valve opening,
Pierre compared valve performance before and after the change.
The Control-Disk valves saved the Kruger mill about $3000/valve in
“avoided” maintenance costs and reduced variability by a factor of
three. Capital and maintenance costs for the installation were minimal,
and downtime due to piping changes was eliminated because the
valves met existing, face-to-face dimensions.

© Fisher Controls International LLC 2009 All Rights Reserved.

Fisher and Control-Disk are marks owned by one of the companies in the Emerson Process Management business division of Emerson Electric Co. Emerson
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The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy they are not
to be construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. All sales
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selection, use or maintenance of any product. Responsibility for proper selection, use, and maintenance of any product remains solely with the purchaser and
end-user.

NORTH AMERICA

Emerson Process Management

Marshalltown, Iowa 50158 USA
T 1 [phone]
F 1 [phone]

www.EmersonProcess.com/Fisher

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Emerson Process Management

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T +(55)(15)238-3788
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Emerson Process Management

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www.EmersonProcess.com/Fisher

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Emerson Process Management

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D351817X012 / MV80 / CD204 / October 2009