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An Audit of the Vacuumsystem
Jim Atkins
Atkins Inc
John CallawayBE K
TApPIQ oo e reaOlc6S BortiQ
ABTCPTAPPIPapetMachineALidils20iJ5 Wet End
Introduction
The basic fundamentals of vacuum
terminologyDifferent kinds of vacuum generatingequipmentReview some aspects of propersystem designExamine vacuum requirements forvarious elements of the papermachine
TAPPIPapetMachineALidils20iJ5 Wet End
Atmospheric Pressure
There is no such thing as vacuum
only the absence of pressure
TAPPIPapetMachineALidils20iJ5 Wet End
Gauge Vs Absolute44 7psia
POSITIVE
PRESSURE
ATMOSPHERICOjnHg
VACUUM 14 7 psia
PRISSURE
10inHgvACUUM 9 pia
NEGATivE
PRESSURE
inHgVACUUM 4 9psia
29 92 irl H9VACUUM 0 0 psia
Figure 1
TAPPIPapetMachineALidils20iJ5 Wet End
30psig
O opsig
143 psig
Vacuum Terms
Standard Cubic Feet Per Minute SCFM thevolume of air under standard conditions of 60oF
and one atmosphere of pressure 29 0 Hg or
100kPa
Actual Cubic Feet Per Minute ACFM the volume
of air under the actual vacuum conditions at 60oF
and 50 relative humidity and 60oF seal water
temperatureTAPPI recommendations and supplier specs are
reported as ACFM
TAPPIPapetMachineALidils20iJ5 Wet
End
Vacuum Terms
Air is a gas and all gases increase in volume
expand when the pressure is reduced and
decrease in volume contract when the pressureis increased
This property of a gas is known as Boyle s law
Pressure x Volume constant
For a fixed amount of gas at a fixed temperature
TAPPIPapetMachineALidils20iJ5 Wet End
The Relationship Between VolumeAnd Pressure
A BASKETBALL @ ATMOSPHERE HAS A DIAMETER
OF ONE FOOT
A BASKETBALL @ 8 INCHES HgV HAS A DIAMETER
of 1 14 feet
A BASKETBALL @15 INCHES HgV HAS A DIAMETER
of 1 26 feet
A BASKETBALL @ 22 INCHES HgV HAS A DIAMETER
of 1 55feet
TAPPIPapetMachineALidils20iJ5 Wet End
GAUGE VS ABSOLUTE
lip is Pressure Absolute0 inH 9
ATMOSPHERI C VACUUM 143 ps 2f1 92 n H 9
PR ESS LJRE
10 nH9
VN ULJM 9 8 PsI
ZOin ijgN EGATIVE
VACUUM 4 9 P Il
P RESS U RE
2fJ fl2 ln HgVACUUM O Opsla
TAPPIPapetMachineALidils20iJ5 Wet End
OlrrHg
Example 1
118
0I
TAPPIPapetMachineALidils20iJ5 Wet End
14 HgV
I
VACUUM SUCTION TUBE
designed for 4 000 cfm @ 14 HgV
What is the volume of air
entering the suction tube
VACUUM PUMP
Example 1
P V P2 V2d
P VV2 1 1
P2
V30 18 1 40002
30 14
V 2 3 000cfm
TAPPIPapetMachineALidils20iJ5 Wet
End
18 Ha
ClJI
TAPPIPapetMachineALidils20iJ5 Wet End
14 Hob
ClJI
VACulTM SUCTION TUBE
tIe ig l j for4 QQO flri@14 Jgo
What is the volume of air
entering the suction tube
VACUUM PUMP
cuum Generating Equipment
10 RING VACUUM PUMPS
a nstant volume device but variable vacuum
CENTRIFUGAL EXHAUSTERS
a variable volume device but constant vacuum
TAPPIPapetMachineALidils20iJ5 Wet End
Liquid Ring Pump Curves
TAPPIPapetMachineALidils20iJ5 Wet End
Manufacturer s specs are
based on actual cubic feet perminute of air ACFM at sea
level 100 kPa or 29 9 Hg
ACFM is determined at 60oF50 relative humidity and
60oF seal water Not mill
conditions
Pump supplier can correct
actual mill conditions
Temperature is more
important as vacuum getshigher May be 15 20
decrease in capacityl
Liquid Ring Pump Curves
TAPPIPapetMachineALidils20iJ5 Wet End
But that s not alii
Might need to correct for altitude
if your mill is not at sea level
Suppose a mill needs 2280
ACFM @20 Hg Mill is 3000
above sea level air tempentering pump is 11 OaF and
seal water is gOoF
Calculated actual required value
is 2680 ACFM @ 22 3 Hg
Liquid Ring Pump Curves
TAPPIPapetMachineALidils20iJ5 Wet End
But that s still not alii
What is the condition of thevacuum pump
Boroscope
Orifice testing
Liquid Ring Vacuum Pump
CHAMBEREXPANDING
ROTOR OFFCENTER
CHAMBERCOMPRESSING
AIRIN
ROTATION
TAPPIPapetMachineALidils20iJ5 Wei End
Below Ground Discharge
li T4i I llT T i i tf i rlTI TI IT TI IT TI IT IT TI IT
1 1m 1 l rn 1 l rn l I n l rn l I
0
nh iy y i rru js C Yi i w
s iyj L it ji i f
7 1Yfl f Vf4c
i1 t4ziE fI lXti NiU X AiC c wy
TAPPIPapetMachineALidils20iJ5 Wet End
Sump Exhaust Velocities
1 500 FPM
1 500 FPM
8 000 FPM
3 500 FPM
Baffle Plate
6Q9 angle
3 500 FPM
TAPPIPapetMachineALidils20iJ5 Wet End
Water Conservation
mp the water from the vacuum trench sump toine white water storage tank
seal water for felt showers
Cascade seal water
Recirculated water through cooling tower
TAPPIPapetMachineALidils20iJ5 Wet End
se The Seal Water For Felt Showers
TAPPIPapetMachineALidils20iJ5 Wet End
Clean Warm Waterto Felt Showersor Recovery
Cascade Seal Water
TemperatureControl Cool
Elm
flWater
IT HotWater
Seal Water Header
TC
rm
11l0
TAPPIPapetMachineALidils20iJ5 Wet End
circulated Through Cooling Tower
Seal Water Header
I I
ib1iMNc
TAPPIPapetMachineALidils20iJ5 Wet End
JI
CoolingTower
6
LevelControl
cuum Generating Equipment
10 RING VACUUM PUMPS
constant volume device
CENTRIFUGAL EXHAUSTED
a variable volume device but constant vacuum
TAPPIPapetMachineALidils20iJ5 Wet End
Centrifugal Exhauster
f t tPra itilg
l Q CouchgiI yp
Automatic Valves
Overload
SafElguarclSyStem
Il
Ehauster
ExhaustHl2at
Figure 11 Water Discharge
TAPPIPapetMachineALidils20iJ5 Wet End
DrivE
TAPPI Technical InformationSheets 3 0
TIS0502 01 VacuumFactors0TIS 0404 27 Felt Conditioning
TAPPIPapetMachineALidils20iJ5 Wet End
T IP Vacuum Recommendations
TAPPI TIP Vacuum Recommendations are based
on empirical data collected from paper mills and
equipment suppliersThey should be used as a starting pointThey are NOT absolute rules for vacuum
application You may find that you need more or
even less vacuum for your particular grade of paperand paper machine
TAPPIPapetMachineALidils20iJ5 Wet End
Example of Information Sheet
T
GRADESBASIS lEIGliT 1 mr LOII VRCWH 1
3000 FT GSM FPn t1Pf1 Jits Wf N IN
LtlOO lNfriJljAllllAlINGlINE BOrlmt11 11lIN 1 I
Nil IfOIiW 1
lO l Il 1 161 2J U 28DS I WI 1 I 1 U 81i lI1 111 10 100 102 H 1 3111 11 1O ijij 1000 oW 1 S16 108 lOi 116 1 112 3 t 16
e
llS OI Q
1 1 581 3 la1 3 31 31 8
3 3u
ClIIIlWlTIIlG IEIlllln S IOO IOe l7Ei 2500 1S2 l 26 3 1 5 38 a I 5 511
8lEfWHO JJlFTSfI PFl EP3IRRD L2Q 300 ISo m 1500 457 5 15 B 2 15 3a I a s 90PAC AulNSPfCIRUIE5 25 100 41 103 2000 610 n 1 2 1 5 215 Q i S 36
fUlp 750 229 S 15 oa 2 3 15 9a n
TAPPIPapetMachineALidils2iJiJ5 Wet End
LOIJ VAC 3
CFIVI5 T
l 35 IiI 3I
1 2 3
I 3 5 5
cuum Drainage Element Installation
CcintrolVilyp
Vacuum
Jail1l912
E1ement
SlopE
TAPPIPapetMachineALidils20iJ5 Wet End
7
Improper Installation
Vacuum Drainage Element
Vacuum header
Control Valve
fl ure13m
TAPPIPapetMachineALidils20iJ5 Wet End
Fix Installation
Vacuum Drainage Element
Vacuum header
Control Valve
TAPPIPapetMachineALidils20iJ5 Wet End
Drainage Element Header Piping
iguJe44
Vacuum Header
Slopeiii Drip
LegConnection PointFrQrn
VacLlum DrainageUnitSeal
Pol
TAPPIPapetMachineALidils20iJ5 Wet End
Improper Header Piping
Vacuum Header
Slope
Connection Point FromVacuum Drainage Units
DripLeg
SealPot
TAPPIPapetMachineALidils20iJ5 Wet End
acuum Pipe Sizing
f Piping design standard is for velocities of5500 fpm for dry air and for wet air 3500
fpmVacuum pump suppliers have pipe sizingcharts available for flow rate at various pipediameters
Separators on all lines
TAPPIPapetMachineALidils20iJ5 Wet End
Pipe Routing
Vh CH R iI co SEF o HOI UU O 1FSIf o HoLLhJJ O P
I C1Y TFRt C Il i I CF R N
rp Wh CLcLL J I ACII
3 0 1 YIN FR HICoul r H i Jr WaRGXLL i7
I 1011A
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o rOP cL j IT V I SOp Hi
f c LEe l ILLIJ IF W I n 1 1 SOP T SIZlDu lDON DROP FCVO U W NII
cr D PiFC IN Cl 1 Uf2 l ACTO
m N F 1 P LlC hPlV JmTlOO T D hQPQP LE H I G npo O
llf I E IJ lC O M m I fm LEV lI T ACUUl II O I nT CR
rt 1 I 2 0
RI S F 1 L 0 0lW 5 en fU EER i Ih
t
M SCDA1 A
11
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s
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t VER C ONf ilJ V N01 co
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Fir Ir C AUV I1IjI P W I yr
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JESIGNDATA
TYPICAL SI pARATOR D SIGNSOI fFS R SE IC l5 A
j IT1 w
1 CIA NI T PPc m c U Yi
2lH NLNC L3 L Wi Wu LII 0
SEAL TANK POl PITfChEST ICOMPARTMtNI DESIGN DMA11
DFSIN DA A I IT W cl llA DKBROP I Fe T B 0 0 fL W OR WEIR
fCFSC COMPIRT rW U 0 00 r
IJSCU Jo e WElRS iECI F oO crlSF l J lAI I c LO P
N r WV 1 00 1ro CYOL I W U wt HP Cro H
H LLU HE ORO G E SEE m Dln IMllL MT
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CSl EN U r N 11 DRO I OS I Q FlmSIJr DlJrJb C CRC HG I O U E
1 1I1 wLl R LWOC Vc rJRLE T 0 oe0vCRlLoN
1UO AI 01 11
1IKI cmr
nn U
TAPPIPapei MachineALidits2iJiJ5 Wet End
f JRW J Vf UU I I
1C I
00i I17 r
11
1I
TYPICAL S PARATO SYSTEMc r 0 51 C 1
V JM DSI WOrA C1 0 A H
Chlt
Pipe Ro
DROP LEG01 DESIGN PIPIN
IF SHORTSIZED FOR v
02 1 DROP LEG 51COMPARTMENOF DROP LE
03 1 END OF ORO1
04 ELEVATION 0IS L 113EXAMPLE 2D
05 DROP LEGSFOR MAX 45THAN 45 OF
TAPPIPaprrl r
TO vlCuj tONTROLLms
IDR Y PJRrROM 5rFIRM Ii
MANlfDLO NDV UJUM CJI ClI LSS ViGUUI MMIP MP I ilf Nnlf 71 Ollbfl
S5DOfrM li PI lVI TAJR E TRANED W AIL HOIA fJI TP 1 riPEN1 f pnXfify T CONOlflOIIINGSERVI2ES ORU RcLL
lij O fPM 12 Pl rl T PIAII IIYPI3500 FPIf 12 prPt
motWIRF Rr XFS VA IFC ILSFELTCQHOITI 1RS WlIlL
HOXfSI ROLL COU II PICK UPTRANSFLP l JIWM ROLc 5 T j
SEE NOTES1IJSrPIIRMOR
CNOTESSIIS2 JIWATER OUT U
NOlLl NOTE 52
V IF S
IRe LEG IL
NOTSDI DSJ o iOff SEl NWE 0 i
MAX 45 LNl rSS Y LlPPROVWIPR oFEREO i U
VERTICALI tV 4 8F SOR
lJTFRNATE JW or SET I
ir
ernElOTTOMOF
W OR WEIR
o CPt1M XI00 GPM USEING
N DROO LEGyr ACTORltIN
EE Non Dil
OW IS NOTEGvOLUME
HATJ 60 VOVG I ow
Q
eo
rNOTESC1 C51
ENDorPIPFINOTEJj
SIZEAN BE C
AS SE ALGNTH c
MINI C4
LEVEL C5RI
SIGN
Pipe Routingo
Cis
No
traps
I Avoid Pockets In The Pipe Line At All Costs ITAPPIPapetMachineALidils20iJ5 Wet End
Problems Shown in Orange
WN
FORMER
0 tJ o
0
PRESS
Q
H H l fHH H fHTAPPIPapetMachineALidils20iJ5 Wet End
One Way to Correct
PRESS
1
LJ
iJ
o0
t CA
di4Ii
IuW1ijS
lJf
U
I I
lJI
TAPPIPapetMachineALidils20iJ5 Wet End
Another Way to Correct
PRESS
FORMER i
L JLoc 0 a
o
Q fJL 9
jh I
rr u
IlII
H 1 rI
IT IT ITI I I I
t l t 1 I J t li l l t 1 1r1
TAPPIPapetMachineALidils20iJ5 Wet End
ilJmmary of Vacuum Audit
Determine the layout of your vacuum systemDesign capacity of the vacuum pumps
How are they connected
How is the piping run
What is the condition of the pumps
How does you system compare with TAPPI TIP s
Correct for actual operating conditions
Look for common piping and installation problems
TAPPIPapetMachineALidils20iJ5 Wet End