Paper360 - November/December 2017 - 38

techlink | VACUUM SYSTEMS

Papermaking Best Practices With
Vacuum-Dewatering Systems: Part 2
DOUG SWEET, P.E.

When creating a long list of best practices relative to paper machine vacuum systems,
they seem to fall into two classifications: Process
and Management. We presented process best
practices in the Sep/Oct issue of Paper 360°.
Here we will look at management best practices.
Considering the essential requirement for
reliable and controllable vacuum for all paper
machine applications (flatboxes, couch, pressing, sheet transfer, and felt dewatering and conditioning) there are many items impacting the
system that are not process-related. Management
best practices are related to personnel, mill procedures and culture, and employee expectations.
The best processes may not be well-managed,
while the best management may provide superior operation of older processes.
TRAINING AND GENERAL
VACUUM SYSTEM KNOWLEDGE
Although we are in a technology boom with
"smart" equipment and computer control, paper
mills can't run themselves. People are still working hard to keep processes within desired operating ranges and when all isn't perfect, they are
hopefully cleaning up and washing down the
machine to get ready for thread-up following
a sheet break. Often, operators with 25 years of
experience are not able to provide basic information or do not understand cause and effect
within these systems. Although training should
be ongoing and applied to all processes, here we
will only discuss specific vacuum systems needs.
Vacuum systems training should begin with
the basics of vacuum measurement. This should
include understanding the difference between
inches of water and inches of mercury. Orders
of magnitude need to be explained to allow
operators to know that full vacuum of about
30 in. Hg is only equal to 15 psi. Often, operators will express vacuum in pounds of vacuum.
A favorite example of a lack of understanding
of vacuum measurement was with a DCS display
showing Deculator vacuum of 31.5 in. Hg (see
Fig. 1.) No one in the control room seemed to be
concerned that this was an impossible value and
that ideal vacuum was about 26 in. Hg.
38

Paper360º

Vacuum measurement is usually found to be as poorly executed
as seal water control. Local gauges
are not maintained and procedures
do not exist to check and calibrate
transmitters. Other issues include
incorrect gauge types (vacuum
vs. compound) and physical locations that are difficult or unsafe
to maintain.
Fig. 1: Does this number bother anyone? No one in the control room
Examples of training needs were seemed to be concerned that 31.5" Hg is an impossible value.
described in Part 1 and included
to be forgotten until serious problems arise.
discussions about table vacuum, seal water
Housekeeping and management supporting
control, cooling towers, and vacuum separaclean mill environments usually result in more
tor systems. Best practices for operator training
frequent interaction with systems not on the
include the following:
operating floor.
* Review and update vacuum system
Many vacuum studies have resulted in findtraining and include understanding of
vacuum measurement and subsystem
ings of basic issues that have been ignored (see
operations (separator/pump systems, seal
Fig. 2.) This can include vacuum and water
water, and cooling towers)
leaks, bearing failures due to excess or lack of
lubrication, inability to identify critical items
* Review vacuum gauge applications and
due to excess grease slinging off the pump
eliminate use of compound gauges-
replace inoperable gauges
shafts, flooded areas due to plugged drains,
and lack of lighting to support basic inspec* Develop improved operator inspection
tions. Mill personnel often end up apologizing
efforts in daily rounds
when some of these relatively simple findings
are discovered once some attention is given to
HOUSEKEEPING
the equipment and system.
Almost nothing in a mill is less technical
Housekeeping Best Practices include:
than housekeeping. However, there are many
* Buy more trash cans, empty regularly
examples illustrating how a clean mill generally
* Clean excess grease following
operates better and more safely. This is truly a
management and mill culture issue.
routine lubrication
* Clean grease and slime from handrails for
I first published my "Earplug Theory" about
safe use
10 years ago. It suggests a correlation between
paper mill operating efficiencies and the num* Consider it unacceptable to clutter floors
and catwalks
ber of discarded earplugs between the paper
* Repair/replace broken lighting-cleaner,
machine and parking lot:
better lighting allows better audits
More earplugs = poor housekeeping =
lower efficiencies.
EQUIPMENT IDENTIFICATION
This theory applies to the vacuum system
Accurate labeling of process piping and
because generally the vacuum pumps are in the
equipment is essential. Physical identification
basement and/or outside the mill. Therefore,
of piping and equipment with easy-to-read
vacuum pumps are out of the normal line of
labeling is necessary (Fig. 3.) Also, process
sight for operators and likely never in the path
drawings and DCS schematics need to show
of a mill tour group. Since vacuum pumps don't
the same information. However, as mills age
usually require a lot of daily attention, they seem

NOVEMBER/DECEMBER 2017

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Table of Contents for the Digital Edition of Paper360 - November/December 2017

Setpoint
Over the Wire
Rebuilds and Conversions
Proud to be a Papermaker
The New Cascades
Operational Data Helps Mills Meet Challenges
Papermaking Best Practices with Vacuum-Dewatering Systems: Part 2
TAPPI Library is an Industry Resource
Managing the Decline of Graphic Paper Demand
TAPPI Journal Summaries
2017 PPI Awards Finalists
TAPPI News
ASPI News
Index of Advertisers
Paper360 - November/December 2017 - Intro
Paper360 - November/December 2017 - cover1
Paper360 - November/December 2017 - cover2
Paper360 - November/December 2017 - 3
Paper360 - November/December 2017 - 4
Paper360 - November/December 2017 - 5
Paper360 - November/December 2017 - Setpoint
Paper360 - November/December 2017 - 7
Paper360 - November/December 2017 - Over the Wire
Paper360 - November/December 2017 - 9
Paper360 - November/December 2017 - 10
Paper360 - November/December 2017 - 11
Paper360 - November/December 2017 - Rebuilds and Conversions
Paper360 - November/December 2017 - 13
Paper360 - November/December 2017 - 14
Paper360 - November/December 2017 - 15
Paper360 - November/December 2017 - 16
Paper360 - November/December 2017 - 17
Paper360 - November/December 2017 - 18
Paper360 - November/December 2017 - 19
Paper360 - November/December 2017 - 20
Paper360 - November/December 2017 - 21
Paper360 - November/December 2017 - 22
Paper360 - November/December 2017 - 23
Paper360 - November/December 2017 - Proud to be a Papermaker
Paper360 - November/December 2017 - 25
Paper360 - November/December 2017 - 26
Paper360 - November/December 2017 - 27
Paper360 - November/December 2017 - 28
Paper360 - November/December 2017 - 29
Paper360 - November/December 2017 - The New Cascades
Paper360 - November/December 2017 - 31
Paper360 - November/December 2017 - 32
Paper360 - November/December 2017 - 33
Paper360 - November/December 2017 - Operational Data Helps Mills Meet Challenges
Paper360 - November/December 2017 - 35
Paper360 - November/December 2017 - 36
Paper360 - November/December 2017 - 37
Paper360 - November/December 2017 - Papermaking Best Practices with Vacuum-Dewatering Systems: Part 2
Paper360 - November/December 2017 - 39
Paper360 - November/December 2017 - Managing the Decline of Graphic Paper Demand
Paper360 - November/December 2017 - 41
Paper360 - November/December 2017 - TAPPI Journal Summaries
Paper360 - November/December 2017 - 43
Paper360 - November/December 2017 - 44
Paper360 - November/December 2017 - 45
Paper360 - November/December 2017 - 2017 PPI Awards Finalists
Paper360 - November/December 2017 - 47
Paper360 - November/December 2017 - TAPPI News
Paper360 - November/December 2017 - ASPI News
Paper360 - November/December 2017 - Index of Advertisers
Paper360 - November/December 2017 - cover3
Paper360 - November/December 2017 - cover4
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