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Static Electricity: Understanding, Controlling, Applying, First Edition.Günter Lüttgens, Sylvia Lüttgens, and Wolfgang Schubert.© 2017 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2017 by Wiley-VCH Verlag GmbH & Co. KGaA.

aabsorption method 84active corona 97act with relevant experience 219–220additive‐depleted surface 50–51adhesion of an insert on a variable

base 227–229adhesive bonding‐blocking 226–227adhesive replacement 226adiabatic compression and shock

waves 11aerials 94aerosol 234–236, 239–240air boundary layers 242alcohol cup 173antistatic 45antistatic packaging 182application of liquid media 234–236application of water, use of charging

during 236asymmetrical rubbing 24ATEX certification 240atmosphere exchange 236

bback discharge 160balun 94bang effect 144, 156basics of fire and explosion

danger triangle 2exothermic reaction of fuel 1explosion‐endangered areas and

permissible equipment 7explosive atmosphere

limits with combustible dusts 6

limits with flammable liquids 3–6metal dusts 6

flammable liquids 15–18fuel 2heat 2–3

vs. oxygen 3hybrid mixtures 6–7ignition sources

adiabatic compression and shock waves 11

cathodic protection 10chemical reactions 11electrical apparatus 10electromagnetic field 10electromagnetic radiation 10flames and hot gases 9hot surfaces 9ionizing radiation 10lightning 10mechanically generated sparks 10static electricity 10ultrasonics 11

inerting process 3minimum ignition energy 11–15oxygen 3permissible equipment 7–9

big storage tanks, two explosions 189–192

bipolar charge layers 124blocking effect 230blocking of newspapers 226blow trunk 190breakdown voltage of a discharge

gap 267Brownian molecular movement 28

Index

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Index278

brush discharges 97–98, 104–108, 162bulk materials 52, 74–75, 130, 132burning handkerchief does not burn

up 174

ccapacitance 38, 259–261

charge decay measurements 79–81coaxial cable/cylinder

capacitance 260conductive sphere in space 260measurement 77–78permittivity value 78–79plate capacitor 261rod (wire) across a conductive

area 259series of single capacitors 261shunt of single capacitors 261sphere across a conductive area 260

capacitive current limit 136capacitive hygrometer 86capacitor 38, 135carbon fiber brush 136carriers 19cast film process 230cathodic protection 10charge 263–264. see also targeted use

of chargescaused by separating

process 149–150conservation 223, 225decay measurements 79–81dissipation 20of electron beam 263mass charge density 264measurement 54–56moved charge 263relaxation with liquids 30–31surface charge density 263–264volume charge density 264

charge decay measuring device QUMAT®‐528 80

charge‐emitting discharge electrode 114

chargingbars 223behavior 41

by gases 31–33of liquids 28–31of particles

many 152–153single 150–152

by separation 160chemical reactions 11chill roll 230–231circular frequency 258classification for flammable

liquids 5–6clean surfaces 128climate 81–82coating machine 237–241coating process 241–243coaxial cable/cylinder capacitance 260“CombiCleaner” operating

principle 128–129combustible organic dusts 6composite materials 125–127conductance 269conductive layers 125, 126conductive sphere in space 260conductive surfaces 135conductivity 30, 51, 269cone discharges 98contact and separation 120core dummy charge 232–233corona discharges 96–97, 104,

161–162corona effect 114corona systems 248–251Coulomb forces 144, 224Coulomb meter 66–67cracks 193current density 240current limiter 134

ddanger triangle 2“decanting” of gasoline

vapors 171–172description of demonstration

experimentscharges caused by separating

process 149–150charging by separation 160

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Index 279

charging of particlesmany 152–153single 150–152

dissipating properties 157–158electric induction

basic experiment 153–154chimes 154–155isolated conductive

parts 155–157electrostatic charging of a

person 158–159electrostatic force effects 144–145

electrical field lines 148electroscope 147–148hovering pipes 146–147rolling pipes 145–146

electrotechnical ideas 139explosion tube 142–144field meter 57, 142fire and explosion dangers

burning handkerchief does not burn up 174

“decanting” of gasoline vapors 171–172

effects with large surfaces 168–169extinguishing with

water 173–174flash point 168inflaming solid

combustibles 174–175oxygen demand 172–173progressive flame front 170–171rich mixture 169–170

gas dischargesbrush discharges 162corona discharges 161–162evidence of ion wind 163–164ignition by brush

discharges 162–163propagating brush

discharges 164–167spark discharges 160–161super brush discharges 163

ignition voltage 159–160preliminary remarks 140–141static voltmeter 141Van de Graaff generator 142–143

visualization 139dew point hygrometry 83–84dielectric strength 117–118direct charge 232dirty discharge electrodes 135discharge electrodes 114discharges, gas 89

avoidable 103–111brush discharge 97–98cone discharges 98consequences of 102corona discharge 96–97electrostatic 90–94mechanisms of 89–90propagating brush

discharge 98–102spark discharge 94–95traces caused by gas 102–103

discharges without electrodes 94discharging charged

surfaces 118–119granules and similar

particles 129–133material webs

behavior of composite materials 125–127

bipolar layers of equal field strength 124

double‐sided discharging 123–124

electric potential 123friction 120nonporous materials 122optimal discharging setup 120,

121optimal placement of discharge

bars 122rerolling process 120–121single‐sided discharging 123static electric shocks 119triboelectric effect 120

other objects 127–129sheets 127–128

discharging granules 129–133discharging of sheets 127–128disruptive discharge 117dissipating property 41, 157–158

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Index280

drying 236–237of fast moving substrates 236–237

dust explosion 130

eeffects with large surfaces 168–169electrical apparatus 10electrical breakdown 90electrical charge 230

coverage 117, 118electrical field lines 148, 235electrical resistance 45electric field 33–36electric induction 156, 224, 225

basic experiment 153–154chimes 154–155image charge 37–38isolated conductive parts 155–157specification of 36–37

electric induction field meter 67electroadhesion 247–248electromagnetic field 10electromagnetic radiation 10electrometer amplifier 54electron density 247electron work function 21electroscope 147–148electrostatic application 223electrostatic charging

with fluids 75–76of liquids 28–30

charge relaxation with liquids 30–31charging by gases 31–33

of a person 158–159of powdery bulk materials 74–75

electrostatic discharge 89, 180electrostatic disturbances prevention

alternating current voltage 114charge‐emitting discharge

electrode 114clean and corroded points 115dielectric strength 117–118discharging charged surfaces 113,

118–119granules and similar

particles 129–133material webs 119–127

other objects 127–129sheets 127–128

empty space 115field line concentration 116–117intentionally charging surfaces 113ionizing electrodes 114passive ionizer 116potential hazards posed by discharge

electrodes 134–136electrostatic effect 236electrostatic force effects 144–145

electrical field lines 148electroscope 147–148hovering pipes 146–147rolling pipes 145–146

electrostatic ignitions, doubts withburst of a glass pipe 218–219fire in a polyethylene

drum 213–215fire in a solvent cleaning

area 215–217electrostatic safety measures 44electrostatic separation 245electrostatic shock 111electrostatic voltmeters 53–54electro‐technical explosion

protection 178energy W of a capacitance 255–256“equipment protection levels”

(EPLs) 8–9equipotential lines 34equipotential surface 34evidence of ion wind 163–164explosion 1

disaster near Bitburg 190–192in a floating roof tank followed by

fire 189–190in a mixing silo for plastic

granules 202in a railcar bulk container 192–193during rotational molding 201–202

explosion dangers, fire andburning handkerchief does not burn

up 174“decanting” of gasoline

vapors 171–172effects with large surfaces 168–169

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Index 281

extinguishing with water 173–174flash point 168inflaming solid

combustibles 174–175oxygen demand 172–173progressive flame front 170–171rich mixture 169–170

explosion range 4explosion tube 142–144explosive atmosphere

limits with combustible dusts 6limits with flammable liquids 3–6metal dusts 6

extinguishing with water 173–174

fFaraday cage 55Faraday pail 55feeder bowls 133fiberglass fabric 169field

field of point charge 256field of rod (wire) charge 257homogeneous field between plane

plates 256lines 33, 34meter 142permittivity 257strength (see field)

fire 1fire extinguishing installation 189–191fixing coverings 227fixing of thin materials 226flames and hot gases 9flammable liquids 15–18flash point 4, 168fluida 20flux density 257force 262

between 2 point charges 262free‐falling objects 55–56frequency

circular frequency 258wavelength 258

frictional electrification 22fuel 2fuel/oxygen mixture 1–2

ggas discharges 89

avoidable 103–111brush discharges 97–98, 162cone discharges 98consequences of 102corona discharges 96–97, 161–162electrostatic 90–94evidence of ion wind 163–164ignition by brush

discharges 162–163mechanisms of 89–90propagating brush

discharges 98–102, 164–167spark discharges 94–95, 160–161super brush discharges 163traces caused by gas 102–103

gasification process with wood 174–175

gas stream 246glass fiber fabric, impregnation

of 186–187Globally Harmonized System

(GHS) 5gravure printing 237–241grounded emitter 93guard ring circuit 47–49

hhair hygrometer 84Helmholtz double‐layer effect 38homogeneous field between plane

plates 256hose filter 208–209hot surfaces 9hovering pipes 146–147humidity 81hybrid mixtures 6–7hygrometers 86–87

iignitability of brush discharges 109ignition by brush

discharges 162–163ignition caused by cone

discharges 212–213ignition of dust 165–166

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Index282

ignitions due to brush dischargesfilling pipe blocked with sulfur

leading to ignition of methanol 187–188

ignition caused by an antistatic PE bag 182–183

impregnation of a glass fiber fabric 186–187

ion exchanger resin in toluene 188–189

PE liner slipping out of paper bag 181–182

pouring flaked product into an agitator vessel 180–181

pumping polluted toluene 185–186shaking fine dust out of a PE

bag 183–185two explosions in big storage

tanks 189–192ignition sources 2, 9–11, 178

adiabatic compression and shock waves 11

cathodic protection 10chemical reactions 11electrical apparatus 10electromagnetic field 10electromagnetic radiation 10flames and hot gases 9hot surfaces 9ionizing radiation 10lightning 10mechanically generated sparks 10static electricity 10ultrasonics 11

ignition voltage 159–160image charge 37–38impedance

of a capacitance 271of a inductance 271–273

impression roller 237indirect charge 233–234inductance, of an air coil 259induction electric field meters 56–58induction field meter 56inerting process 3inflaming

a dust heap 175

solid combustibles 174–175ink particles 239in‐mold‐decoration (IMD) 232–234in‐mold‐labeling (IML) 232–234intermediate layers 227investigation, strategy of 177–178

general approach 179hasty consequence 179–180ignition sources 178–179

ion exchanger resin in toluene 188–189

ionization 89–91ionizing electrodes 114ionizing radiation 10ions 89–91ion wind 97

kKasuga Denki KSD System 61–62Kirchhoff ’s junction rule 266Kirchhoff ’s loop rule 266

llaminar air boundary layers 234laminar airflow 234–237laminar airflow boundary layer 236leakage current 240leakage resistance 269Lewis acidic surfaces 119Lewis base surface 119Lichtenberg discharges 98lightning 10lithium‐chloride hygrometer 85–86lower explosion limit 4

mmass charge density 264material separation 246maximum allowable capacitance 104maximum allowed surface area 105measurement methods. see also

metrologyelectrical resistance 45realization of resistance

measurements 46–49measuring area E‐field meter 64measuring area piezo sensor 65

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Index 283

mechanically generated sparks (MGSs) 10

mechanism of charging 19metallic dust 6metrology

additive‐depleted surface 50–51applications of induction electric field

meters 65–67bulk materials 52capacitance 77–81conductivity of liquids 51discharge capacity 71–73electrostatic charges in chemical

production 76–77electrostatic charging of powdery

bulk materials 74–75electrostatic charging with

fluids 75–76electrostatic safety measures 44electrostatics/electrical

engineering 44–45electrostatic voltmeters 53–54errors when measuring field

strength 58–61Faraday pail 54–56induction electric field

meters 56–58measurement methods

electrical resistance 45realization of resistance

measurements 46–49protective textile clothing 68–71surface charge on moving webs 68test procedure for paper 73–74themes around air

humidity 81–87types of electric field

meters 61–65use of insulating material in

endangered areas 52walking test 41–43

microampere meter 161micronizer jet mill, ignition in a 200minimum ignition energy

(MIE) 11–15miraculous earthing clamp 212modified ball electrode 67

modified induction electric field meter 66moved charge 263mutual binding effect 99

nn‐hexane 207–208

ooil application 234oil suction granules 168, 169one‐electrode discharges 95opposite‐ and similar‐poled

charges 224Optical‐Web‐Tension‐Profile‐

Scanner 244oxygen 3oxygen demand 172–173

ppaper ribbon 230particle mist 241–243passive corona 97passive discharge electrode 136passive ionizer 116, 240permittivity 257permittivity value 78–79Perspex® tube 142Picoampere meter 67pinch effect 91pipe ionization 131plasma 92plate capacitor 261polluted toluene pumping 185–186potential 264powder heap discharge 98. see also

cone dischargesprint cylinder 237progressive flame front 170–171propagating brush discharges 98–100,

118corona needle 164curiosity during outflow of liquid

from a metal pipe 202–204explosion during rotational

molding 201–202explosion in a mixing silo for plastic

granules 202

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Index284

propagating brush discharges (contd.)explosion in a railcar bulk

container 192–193failed attempt to eliminate

electrostatic nuisances 195–197

fire in a spray‐bed dryer 197–200ignition in a micronizer jet

mill 200ignition of dust 165–166metal drum with inner

liner 193–195plastic drum with inner liner 195short circuit of a double‐layer

charge 166–167protective textile clothing

test procedures with electrostatic influence 69–71

triboelectric test procedure 69psychrometer 84–85

qquenching distance 95

rrecombination 114relaxation time 225resistance 267

conductance 269conductivity 269impedance of a capacitance 271impedance of a inductance 271–273leakage resistance 269measurements 46–49resistivity of a conductor 268series 270shunt 270surface resistivity 268volume resistivity 268

resistive/capacitive coupling 134resistive hygrometer 86resistivity of a conductor 268ribbon tacking 230rich mixture 169–170rod (wire) across a conductive

area 259rolling pipes 145–146

ssawtooth sequence 162semiconductive rollers 230separation of pollutants 246series of single capacitors 261series resistance 270short‐circuit effect 92short circuit of a double‐layer

charge 166–167shunt of single capacitors 261shunt resistance 270sliding discharges 100space charge clouds 114spark discharges 94–95, 104, 135,

160–161alternative restrictions on insulating

solid materials 219–220dust removal from pharmaceutical

pills 205–206filling n‐hexane into metal

drums 207–208hose filter 208–209lost and found 211–212miraculous earthing clamp 212powder explosion in a metal

drum 204–205sparks at a throttle valve 206–207water flowing through PVC

hose 210–211spark‐gap transmitters 92sphere across a conductive area 260spray‐bed dryer, fire in a 197–200static electricity 10

basics 19–21capacitance and capacitor 38electric field 33–36electric induction

image charge 37–38specification of 36–37

electrostatic charging of liquids 28–30

charge relaxation with liquids 30–31

charging by gases 31–33electrostatic charging of

solids 21–23surface resistivity 24–28

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influence of surface texture on static charging 28

triboelectric series 24static voltmeters 53–54, 141stoichiometric value 12stored electrical energy 44super brush discharges 98, 104–106,

163supercapacitors 38surface charge density 263–264surface resistance 48surface resistivity 24–28, 48, 268surface texture 28surface treatment with corona

systems 248–251

ttargeted use of charges

adhesion of a melt layer on the chill roll 230–231

adhesion of an insert on a variable base 227–229

adhesive bonding ‐ blocking 226–227

application of liquid media on fast moving webs 234–236

applications 223–225avoiding telescoping when

winding 231–232blocking a number of paper webs or

film webs in one ribbon 229–230

drying of fast moving substrates 236–237

electroadhesion 247–248gravure printing and coating

machine 237–241in‐mold‐labeling‐in‐mold‐

decoration 232–234oil application on metal

sheets 234precipitation of mixed

substances 244–247reduction of particle mist in the

coating process 241–243surface treatment with corona

systems 248–251

use of charging for technical measurement processes 243–244

telescoping 231–232thin laminates 226time constant 266traces caused by gas

discharges 102–103Trek contact voltmeter 64triboelectric series 24, 150triboelectric test procedure 69two‐electrode discharges 94

uultrasonics 11upper explosion limits 4

vVan de Graaff generator 142–143vibratory conveyors 133voltage 265–267

breakdown voltage of a discharge gap 267

in a homogeneous electric field 265Kirchhoff ’s junction rule 266Kirchhoff ’s loop rule 266time constant 266voltage gradient when charging a

capacitor 265voltage gradient when discharging a

capacitor 265voltage/current principle 46voltage gradient

when charging a capacitor 265when discharging a capacitor 265

voltmeters 53–54volume charge density 264volume resistance 46–47volume resistivity 46–47, 268

wWalking Test 41–43wavelength 258web tension profile 243

zzones 7

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