Advanced Belt Winding

Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
Adv
vance
ed Be
elt Winding
g for Tissu
ue
Executtive Summ
mary
The perfo
ormance of a high-speed
h
tisssue machine depends greaatly on the peerformance off the dry end. At
the dry en
nd, the sheet is
i transferred from the crep
ping blade to the winding n
nip on the reeel. There are
different demands
d
on the
t dry end an
nd equipmentt used dependding on the tyype of tissue b
being produceed on
the machiine.
Valmet offfers a wide raange of differeent reel types; the latest of these is the A
Advantage™ So
oftReel B which
winds thee tissue roll on
n a belt.
Winding on the belt reesults in gentleer winding, im
mproving thee control of th
he winding prrocess and
enabling production
p
off large diametter parent rollls while keepiing a uniform
m caliper throu
ughout the en
ntire
roll. The belt
b together with
w blow boxxes also impro
oves sheet con
ntrol before tthe winding n
nip and reducces the
length of free
f sheet draaw in the dry end.
e
Advantagge SoftReel B is
i a valuable tool for produ
ucing and presserving high qquality tissuee paper properrties
such as hiigh bulk, softn
ness and calip
per, while min
nimizing brokke and improvving the prod
duction efficieency
of convertting operation
ns. This givess a competitivve advantage tto premium tiissue and tow
wel producers.
© Valmet
Page |
1
Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
Introdu
uction
The perfo
ormance of a high-speed
h
tisssue machine depends greaatly on the peerformance off the dry end. At
the dry en
nd, the sheet is
i transferred from the crep
ping blade to the winding n
nip on the reeel. There are
different demands
d
on the
t dry end an
nd equipmentt used dependding on the tyype of tissue b
being produceed on
the machiine.
A prerequ
uisite for efficient operation
n is productio
on of paper off the correct p
properties on
n the tissue
machine. Another is paassing these properties
p
on to the converrted end prod
duct. It is a kn
nown fact thatt the
a such as hiigh softness, bbulk and low tensile strenggth, the more
more delicate the tissuee properties are,
difficult th
hey are to pro
oduce efficien
ntly.
Valmet haas developed multiple typees of reels for producing vaarious types oof tissue at diff
fferent machin
ne
speeds. Th
he Advantagee SoftReel B em
mploys a com
mpletely new ttissue windin
ng technologyy and is the neew
member of
o the reel fam
mily.
With Advvantage SoftReel B, the B sttands for Beltt. In this new ttissue windin
ng technologyy, a belt replacces
the reel drrum found in
n conventionaal winding sysstems. Windin
ng with a beltt allows tissuee makers a
competitivve advantage.
This innovative system
m gives produccers and convverters of prem
mium tissue aand towel graades a compettitive
edge in an
n industry wh
here greater effficiency and minimum
m
brooke directly aaffect the prod
ductivity.
The ch
hallenges of winding premium quality tissue
Winding of tissue prod
ducts at high speeds
s
is challlenging. The difficulty inccreases when rrunning prod
ducts
ulk and low teensile strength
h. The initial winding on th
he reel spool and the contrrol of the lineear
of high bu
load are critical operatiions, which when
w
perform
med properly, m
minimize wasste on the roll.
Diffeerent types off reels offer tisssue
makkers a wide ran
nge of options for
prod
ducing variou
us types of tisssues
at diifferent machiine speeds
(Figu
ure 1).
The standard reell for a dry crepe
ue machine is a reel with
tissu
pivoting arm with
h a hydraulic
loading system. T
The most advaanced
of th
he standard reeels utilize a liinear
loading system wiith CWA (Ceenter
Win
nd Assistance)). All of these reels
are bbased on wind
ding on the reeel
drum
m.
Figure 1. Valmet provide
es different reelss for different winding
w
challengges.
© Valmet
Page |
2
Published September
S
30, 20
014
In recent years,
y
the tisssue industry
has deman
nded improveed control of
the windin
ng process to enable
producingg large diameter parent
rolls whilee achieving un
niform
caliper thrroughout the whole roll.
In response to this dem
mand, Valmett
developed
d a new reel, the
t belted
reel, which is based on winding on
a belt insttead of the reeel drum
(Figure 2).
Advanced Belt
B Winding for T
Tissue
Figure 2. The Advantaage SoftReel B foor tissue incorpo
orates a belted rreel
for gen
ntle winding.
Windin
ng princip
ple
One of the benefits of the
t belted reel technology, compared too conventionaal winding, is the fact that iit
permits producing largge parent rollss of uniform caliper
c
througghout the rolll (Figure 3). A
As mentioned
d
placing the reeel drum in
earlier, rep
conventio
onal winding systems
s
with
a belt is what
w
makes the difference.
For the paast 60 years, tiissue paper
and towell grades of low
w density and
d
low tensile strength havve been
wound in the same wayy as "flatgrade" pap
per of high deensity and
high tensiile strength. That
T is to say
both typess of paper havve been fed
into a nip consisting off a reel drum
and the paarent roll.
Figure 3. The belted reeel provides more uniform wind
ding during the
windin
ng process, preseerving caliper thhroughout the rroll.
The inden
ntation caused
d by the nip lo
oad in the casse of "flat-gradde" paper of h
high density iis small and teends
not to varry much in sizze as the diam
meter of the paarent roll incrreases. Conseqquently, thesee parent rolls can
be wound
d with an acceeptable uniforrm caliper thrroughout the rroll (Figure 44, next page).
Using thiss conventionaal technology for winding premium
p
tisssue and towel grades does n
not produce tthe
same good
d results as when
w
winding high-density paper becausse the indentaation caused b
by the nip loaad is
larger than with high-d
density paper and becomess even larger aas the diameter of the pareent roll increaases
(Figure 5,, next page).
When low
w-density pap
per such as tisssue and towell grades are feed into a nip cconsisting of a reel drum aand
the parentt roll, the lenggth of contactt, "A" of the parent roll bein
ng wound beccomes longerr as the diameeter of
the roll in
ncreases, makiing it difficultt to control th
he wound-in ttension in thee roll. Conseq
quently, these
parent rollls are not of uniform
u
calip
per throughou
ut the roll, wh
hich limits thee diameter and the speed aat
which theey can be wou
und, but also unwound
u
in converting
c
lin
nes (Figure 6,, next page).
© Valmet
Page |
3
Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
Fiigure 4. Winding
g high density paper
p
on conven
ntional winding ssystem – little oor no indentation
n.
Fiigure 5. Winding
g low density pa
aper such as tisssue on conventioonal winding syystem - drum ind
dents into paren
nt roll.
Fiigure 6. Geomettry of indentatio
on for low density paper. Tensioon decreases whhen roll is largerr than reel drum
m.
© Valmet
Page |
4
Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
How th
he belted
d reel worrks
Replacingg the reel drum
m with a belt changes the physical
p
naturre of the nip. Instead of a rround, hardsurfaced reel
r drum and
d parent roll, the
t belted reeel technology enables the tiissue and tow
wel grades to m
meet
a flat, softt-surfaced belt in the nip.
In other words,
w
the len
ngth of contacct
A is alwayys shorter than the arc B
even as th
he diameter off the roll
increases. When the tisssue exits the
nip the sh
heet is elongatted and thus
tension is generated inside the roll.
The resultt is consistentt control of th
he
wound-in
n tension. And
d this is why
the belted
d reel is able to
o produce
uniform large parent ro
olls of
premium tissue and tow
wel grades – at
a
high speed
ds (Figure 7).
The nip pressure
p
again
nst the belt is
significan
ntly lower than
n the nip
pressure in
i a conventio
onal reel. Thiss
reduction
n preserves thee caliper of th
he
sheet duriing winding. Figure
F
8
compares the nip presssure for a
conventio
onal reel and the
t belted reeel
with a typ
pical indentatiion setting.
Figu
ure 7. With belt w
winding A is alw
ways less than B
B, which results iin
increeased wound-inn tension throug
ghout the roll.
Figure 8. Nip pressure in a conventionall reel vs. the beltted reel. Belted winding provide
des a better startt, with only 1/5 of
the nip pressure required
d by convention
nal reels. Lower nip
n pressure preeserves bulk.
A good start of a new
n
roll
Using beltted reel techn
nology in the tissue
t
machin
ne reduces brooke when threading and tu
urning up tisssue of
low-tensille strength. Compared to conventional
c
winding,
w
its n
nip is soft and
d forgiving ratther than hard
d and
© Valmet
Page |
5
Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
uncontrolllable, which often
o
causes sheet
s
breaks at
a turnups andd contributess to low operaating machinee
efficiency. The belt nip
p is soft and it deflects if, fo
or instance, th
he core surfacee is not perfecct.
The belted
d reel allows producing
p
large pareent rolls of miinimal caliperr
variation throughout th
he roll. This
means pap
per of consisttent caliper is
fed into th
he machines in
i converting
operation
ns, which translates into
better con
ntrol of these operations.
Relative Volume of Paper (%)
The be
enefits off large parent rollss
160
0
140
0
1.44xx
120
0
100
0
2.76x
80
0
1.92x
60
0
40
0
20
0
00
0
A convertting plant that handles largge
72
100
120
diameter rolls enjoys greater
Roll Diameter (inches)
efficiency than one han
ndling smallerr
Figu
ure 9. The relativve volume of pap
aper increases drramatically as th
he
rolls. For example, the broke each
roll diameter
d
increaases.
parent rolll generates deecreases,
which, of course, increases overall efficiency (Figgure 9).
meter of the parent
p
rolls prroduced on a tissue machin
ne is increased from 100 to
o 120 inches, the
If the diam
amount of tissue paperr on each pareent roll will in
ncrease by 44%
% (1.44 timess), and therefo
ore larger rollls
benefit no
ot only tissue making but also
a convertin
ng operations..
Note: Thee belted reel iss capable of winding
w
up to 140" diameteer with excelleent winding rresult, but thiss
large diam
meter would require
r
speciaal designs for buildings
b
andd roll handling, instead forr the example
shown in Figure 9 we have
h
used 1200" diameter fo
or the comparrison.
Less parent roll ha
andling to converting
g plant
If a conveerting plant un
nwound 30,0000 tpy of pareent rolls in diaameters of 1220 inches (30000 mm) insteaad of
100 inches (2500 mm),, it would unw
wind 30% few
wer parent rollls, or approxiimately 6,000 fewer parentt rolls
h
lead
ding to logisticcs savings (claamp truck cossts, labor saviings, etc.).
each year would need handling
Waste//broke redu
uction
Each pareent roll has tw
wo types of waaste, strip wasste generated bby moving th
he parent reel and core wasste
which is the paper left on the core att the end of th
he reel. Depen
nding on how
w the parent rreel is moved and
handled, strip
s
waste caan be anywherre between 0%
% (handled byy an automatiic guided veh
hicle) to 3-5%
(handled by
b a clamp truck). Core waaste is typically 2 to 3%. Foor a 30,000 tpy converting operation,
reducing the
t number of
o rolls to be unwound
u
each
h year by 30%
% means reducing the amount of strip an
nd
core wastee by 600 tpy, or converselyy 600 tons mo
ore of convert ed product.
Furtherm
more a more co
onsistent wind
d throughoutt the parent rooll means there is more useeable paper
towards th
he core which
h can reduce the
t core wastee even furtherr.
© Valmet
Page |
6
Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
Reductiion in the number
n
of parent roll cores req
quired
Every tim
me a parent rolll core goes th
hrough the tisssue machine and converting process it suffers wear aand
tear. By deecreasing the amount of paarent roll han
ndling by 30%
% there will bee 30% less cyccles on each parent
roll core saving
s
approxximately 30% on replacemeent parent reeel core costs p
per year. A typ
pical 102 inch
h
(2.5m) wiide parent rolll core cost is approximatel
a
ly $ 75/ core. IIn our examp
ple of 6000 few
wer parent ro
olls a
savings off 600 cores peer year can be realized, assu
uming that a ccore can be reeused 10 timees (cycles).
Greaterr converting line prod
ductivity
Parent rolll changes con
ntribute betw
ween 5% to 12%
% time efficieency loss on a converting liine. Larger
diameter parent
p
rolls will
w mean morre running tim
me between reeel changes, d
driving uptim
me and producctivity
on the con
nverting line. In our 30,0000 tpy examplee, assuming itt takes approxximately five minutes to ch
hange
a parent roll
r and there are 6,000 few
wer parent rolll changes per year, there w
will be an addiitional 500 ho
ours
of additional convertin
ng capacity orr 1,760 tpy of converted prooduct (Figuree 10).
Sav
vings
Rolls/Cores
Less parent
p
roll hand
dling
30
0%
-6000 rolls
Brroke reduction
30
0%
Core reduction
30
0%
Increased efficienccy
Tottal savings and
pro
oductivity gain
ns
T
Tons/year
Saving/G
Gain $/year
-600
-600 cores
+1760
$,$$$,$$$
Figure 10.
1 Worksheet for
f savings and gains
g
achieved with belted reelling at a 30,0000 tpy converting plant by unwind
ding
120" ra
ather than 100" diameter paren
nt rolls.
The be
enefits for convertting opera
ations off consiste
ent calipe
er controll
during the wind
ding proccess.
Minimizin
ng caliper varriation througgh a parent ro
oll is critical foor high-speed
d operation off a convertingg line.
Caliper vaariation throu
ughout a parent roll will caause convertedd product rolll diameter an
nd density to vvary
which in turn
t
creates productivity
p
isssues.
Equipmen
nt such as logg saws and higgh-speed wrap
ppers are set tto process rollls of a certain
n diameter. As the
caliper deecreases throu
ugh a parent roll
r the converrted product diameter can
n decrease and
d the rolls beccome
soft causin
ng issues at th
he log saws (lo
ong and shortt rolls) and w
wrappers (soft and loose packs).
Sometimees the quick fiix is to add exxtra sheets to compensate
c
ffor this probleem which results in addingg
fibers and
d consequentlyy adding unn
necessary cost to each case of finished prroduct.
The belted
d reel windingg technique reduces
r
this prroblem due too a more conssistent caliperr control duriing
the windin
ng process. On
O the next paage we describ
be how this iss achieved witth an innovatiive and paten
nted
control strategy and measurement technique.
© Valmet
Page |
7
Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
Mecha
anical dessign and control
c
sttrategy
The belted
d reel builds on
o decades off reeling experrience by usin
ng the same p
platform as a cconventional reel
(Figure 11).
Figure 11
1. Belted vs. Con
nventional reel – both use the sa
ame mechanicaal platform.
d reel is equip
pped with lineear primary arms and secoondary carriagges with a cen
nter wind assist, a
The belted
short belt run with a stretcher and guide
g
mechan
nism (Figuress 12 & 13).
Figure 12
2. The belted ree
el design uses a permeable
fabric/be
elt to support th
he winding paren
nt roll
througho
out the building of the roll.
Figure 13. Thhe main componnents of the beltted reel include
the belt, blow
w boxes, stretchher and guide, p
primary arms an
nd
secondary linnear carriages.
d
than that of a convventional reell. As the paren
und
nt roll is wou
The contrrol strategy is completely different
against th
he belt, the con
ntrol algorithm calculates the
t required iindentation oof the parent rroll surface in
nto
the belt. Figure
F
14 (nexxt page) show
ws Valmet's patented strateegy for measu
uring indentattion.
This contrrol strategy reelies on an absolute distancce measurem ent to measurre indentation
n, as well as
measuringg the windingg speed and th
he RPM of thee parent roll, which provid
des the outputt for positioning
the second
dary carriagess. This contro
ol strategy is based
b
on posittion control iinstead of meeasuring the liinear
load betw
ween the paren
nt roll and thee winding surrface.
© Valmet
Page |
8
Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
Measuring linear load with
w load
cells is a well-known
w
teechnology.
In tissue applications
a
th
his
techniquee has several difficulties
d
because th
he measured and
a
controlled
d values are of the same
magnitud
de as friction and
a
hysteresiss between the load cell
and the niip point. Meaasuring the
indentatio
on provides direct
d
feedback of
o the variables required
for contro
ol.
Figure 14
4. Valmet's pateented strategy foor measuring indentation
Dry En
nd equipm
ment for high-spee
h
ed operattion
A state-off-the-art dry end
e incorporaates a belted reel
r as well as a number of components that enhancee the
overall effficiency of tisssue machine operations
o
(F
Figure 15):
•
•
•
•
•
•
Wet
W dust colleectors. Dust collector
c
scrub
bs dust directtly into the waater in the colllector.
Runnability
R
co
omponents. Collects
C
dust directly from
m the surface oof the sheet.
Blow
B
boxes. Sttabilizes the sh
heet on the belt before enttering the win
nding nip.
Water
W
jet turn
nup. For efficiient full width
h turnups at h
high speeds.
Water
W
jet edgee trim. Cuts trim at the dryy end.
Water
W
jet slitter. Splits the sheet into two
o or more rollls.
Figure 15. State-of-the-arrt dry end layout with belted reeel
During th
he past decadee numerous reeels based on Valmet's beltt winding tech
hnology havee been deliverred.
© Valmet
Page |
9
Published September
S
30, 20
014
Advanced Belt
B Winding for T
Tissue
Summary
The belted
d reel technollogy is an exceellent technollogy for windding premium
m tissue and to
owel grades. IIt is a
valuable tool for produ
ucing and presserving high quality
q
tissue paper properrties such as h
high bulk, sofftness
and calipeer, while miniimizing brokee and improving the produuction efficien
ncy of converting operations.
The Advaantage SoftReeel B is capablee of winding large
l
diameteer parent rollss up to 140" diameter, whille
reducing parent
p
roll haandling and th
he number off cores requireed.
The belted
d reel technollogy is a matu
ure technologyy, developed and refined oover a period of more than
n 10
years. Beltted reel windiing technologgy is availablee as an option for all new an
nd existing tissue machinees.
This white paper combine
es technical infformation obtaiined from Valm
met personnel a
and published V
Valmet articless and
papers.
ovides competittive technologie
es and services to the pulp, e
energy and pap
per industries. Valmet's pulp, paper
Valmet pro
and powerr professionals specialize in prrocesses, mac
chinery, equipm
ment, services, paper machine
e clothing and filter
fabrics. Ou
ur offering and experience
e
cov
ver the entire process
p
life cyccle including ne
ew production lilines, rebuilds a
and
services.
We are com
mmitted to mov
ving our custom
mers' performance forward.
© Valmet
Pag
ge |
10