Audting the vacuum system

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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

Basic Fundamentals OfVacuum Systems 1 0


Atmospheric Pressure

There is no such thing as vacuum

only the absence of pressure


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


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


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


s Law

P1 V P2V2


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


OlrrHg

Example 1

118

0I


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


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


Liquid Ring Pump Curves




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



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



But that s still not alii

What is the condition of thevacuum pump

Boroscope

Orifice testing

Liquid Ring Vacuum Pump


Liquid Ring Vacuum Pump

CHAMBEREXPANDING

ROTOR OFFCENTER

CHAMBERCOMPRESSING

AIRIN

ROTATION

TAPPIPapetMachineALidils20iJ5 Wei End

uum System Installation 2 0


Typical Installation

PRESS

FORMER

o

t1TAPPIPapetMachineALidils20iJ5 Wet End

ical Vacuum Pump Arrangement

TAPPIPapetMachineALidits20iJ5 Wet 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


Sump Exhaust Velocities

1 500 FPM

1 500 FPM

8 000 FPM

3 500 FPM

Baffle Plate

6Q9 angle

3 500 FPM


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


se The Seal Water For Felt Showers


Clean Warm Waterto Felt Showersor Recovery

Cascade Seal Water

TemperatureControl Cool

Elm

flWater

IT HotWater

Seal Water Header

TC

rm

11l0


circulated Through Cooling Tower

Seal Water Header

I I

ib1iMNc


JI

CoolingTower

6

LevelControl

cuum Generating Equipment

10 RING VACUUM PUMPS

constant volume device

CENTRIFUGAL EXHAUSTED

a variable volume device but constant vacuum


Centrifugal Exhauster



0

0

i li



f t tPra itilg

l Q CouchgiI yp

Automatic Valves

Overload

SafElguarclSyStem

Il

Ehauster

ExhaustHl2at

Figure 11 Water Discharge


DrivE

TAPPI Technical InformationSheets 3 0

TIS0502 01 VacuumFactors0TIS 0404 27 Felt Conditioning


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


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

Vacuum Augmented DrainageElements 4 0


cuum Applications on the PM

0


cuum Drainage Element Installation

CcintrolVilyp

Vacuum

Jail1l912

E1ement

SlopE


7

Improper Installation

Vacuum Drainage Element

Vacuum header

Control Valve

fl ure13m


Field Examples


Field

Examples

TAPPI Paper MachineALidit

Fix Installation

Vacuum Drainage Element

Vacuum header

Control Valve


Drainage Element Header Piping

iguJe44

Vacuum Header

Slopeiii Drip

LegConnection PointFrQrn

VacLlum DrainageUnitSeal

Pol


Improper Header Piping

Vacuum Header

Slope

Connection Point FromVacuum Drainage Units

DripLeg

SealPot


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


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

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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

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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

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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

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TAPPIPapei MachineALidits2iJiJ5 Wet End

f JRW J Vf UU I I

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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

uum Piping Examples 5 0

I What do you see wrong I


What is Wrong with the PipingPRESS

FORMERJu

Q

I I

j t

r p


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

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lJI


Another Way to Correct

PRESS

FORMER i

L JLoc 0 a

o

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IlII

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IT IT ITI I I I

t l t 1 I J t li l l t 1 1r1


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


An Audit of the Vacuumsystem

Jim Atkins

Atkins Inc

John CallawayBE K

TApPIQ oo e reaOlc6S BortiQ

ABTCPTAPPIPapetMachineALidils20iJ5 Wet End

Audting the vacuum system

Engineering

Transcript of Audting the vacuum system