Straight pipe model. Orifice model. * Please refer to Page 3~7 Reference Material for the theoretical formulas used here. Qa/Qw=(ηw/ηa) (P1+P2)/(2 P2)

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1 Air lek test equivlent to IX7nd IX8 In order to perform quntittive tests Fig. shows the reltionship between ir lek mount nd wter lek mount. Wter lek mount cn be converted into ir lek mount. By performing n ir lek test ccommodting wter lek llownce equivlent to IX7 nd IX8, qulity control using ir lek mount (numericl is possible, nd there is better chnce of preventing wterproof defective products from leking out to customers. A wter lek mount with no hrmful effect IX7 nd IX8 re designted s Ingress of wter in quntities cusing hrmful effects shll not be possible. There is need to determine the wter lek mount (permissible mount which hs no hrmful effect. If this vlue is stipulted, wterproof tests within ir lek tests will be possible. Below is n introduction on how ir converted mount is found presuming two types of lek hol e models (orifice nd stright pipe nd ssuming wter lek permissible mount of 0.09 ml/30 minutes. Stright pipe model According to the Hgen oiseuille lw, /w=(w/ (+/( Viscosity coefficient w= sec 0 = sec 0 Upwrd pressure. 0 bs Orifice model According to the orifice flow formul (JIS876- /w= ε ρw/ρ (ε:expnsion compenstion coefficient If the below is the cse; upwrd pressure. 0 bs downwrd pressure.0 0 bs (bsolute pressure reference Wter density ρw=997kg/m 3 t Downwrd pressure.0 0 bs Air density ρ=.kg/m 3 t Averge pressure.06 0 bs /w=8.0 If the permissible limit of wter lek mount (w ws ssumed to be 0.09mL/30 minutes (w= 0 - m 3 /s, the ir volume flow rte would be = m 3 /s. The ir lek mount would then be found by multiplying the then /w=ε 8.3=8.3 (Assuming tht nd re close then ε JISZ876- If the permissible limit of wter lek mount (w ws ssumed to be 0.09mL/30 minutes, from w= 0 - m 3 /s, the ir volume flow rte would be =. 0-9 m 3 /s. The ir lek mount would then be found by multiplying the verge verge pressure, therefore m 3 /s (Δ=9.8k. pressure, therefore. 0 - m 3 /s (Δ=9.8k Averge pressure.06 0 bs * lese refer to ge 3~7 eference Mteril for the theoreticl formuls used here.

2 Mesurement vlue with n ir lek tester presuming n IX7-equivlent test is performed. Compred with the stright pipe model, the orifice model uses conditions whereby ir leks nd wter leks could esily occur, therefore the orifice model ir lek mount nd wter lek mount rtio of /w=8 is pplied nd the reltionship between ir/wter lek mounts is shown in the below figure. Fig. eltionship between ir lek mount nd wter lek mount

3 eference Mteril efer to FUKUDA Technicl Mnul.6~9 Lekge of Gs or Fluid (Viscous Flow Lekge is phenomenon which occurs when fluid such s ir, wter, or oil psses through n unintended opening such s smll hole. A resultnt lek volume differs ccording to the difference of pressure cross the opening; nd reltes with the ese of fluid flow through the opening; conductnce. This cn be expressed by the following eqution. = C ( (. Where is lek volume, represents the difference between two pressures, nd C is conductnce. When lekge is the subjective problem, the ese of fluid flow (C depends on vriety of fctors, including the configurtion of the opening, length, etc. It is therefore difficult to pply one type of eqution to ll cses. In this section, n explntion is given using generl ppliction equtions. Theoreticl Eqution of Lek Volume As representtive theoreticl eqution to explin the behvior of fluids pssing through very nrrow opening, the Hgn-oiseuille Lw is often used. According to this lw if the opening is so smll tht the flow of fluid is within rnge of viscous flow (lminr flow, nd the rtio of the hole length vs. the hole dimeter is lrge enough, the following eqution cn be pplied; π ( (. Where is the volumetric flow of outlet side pressure (tmospheric pressure converted from compressible fluid such s ir. However, if is negtive, the lek volume is expressed in terms of the stte of tmospheric pressure. The in the denomintor in eqution. is replced with. With volumetric flow rte W representing non-compressive fluid such s wter, oil, etc. the following eqution is pplied; W π ( 8W (.3 : Volumetric flow rte of compressive fluid (ir under pressure w : Volumetric flow rte of non-compressive fluid (ml/s : rimry (test pressure (when negtive pressure, tmospheric pressure ( : Secondry (test pressure (when negtive pressure, test pressure ( : dius of the opening (cm l : Length of the opening (cm : Viscosity of compressive fluid ( s : Viscosity of non-compressive fluid ( s w (ml/s l in-hole of dius Fig.. Theoretic Model of Lekge The reltionship of volumetric flow rte influenced by the difference between gseous fluid nd liquid, nd between two pressures with the sme test piece is shown in Tble.3. efer to equtions. nd.. 3

4 Tble.3 eltionship between Lek Volume vs. Test ressure nd Viscosity Condition eltive Eqution The rtio of lek volume to the different test pressures towrds the sme gs. x y x y x y Gs The rtio of lek volume to the fixed test pressures towrds different gses. x y y x The rtio of lek volume to the different test pressures towrds different gses. x y y x x y x y The rtio of lek volume to the different test pressures towrds the sme liquid. wx x y x y Fluid The rtio of lek volume to the fixed test pressure towrds different liquids. wx wx The rtio of lek volume to the different test pressures towrds different liquids. wx = wx x y x y Gs/ Liquid The rtio of lek volume to the different x ( x x test pressures towrds different gses nd liquids. x(y y x The rtio of lek volume to the fixed test pressure towrds different gses nd liquids. x x (

5 Viscosity (Viscosity Coefficient Viscosity is one of the importnt fctors when hndling fluid. Different units re used in different fields. Here re some exmples; s = N s m - = kgf s cm - = 0 :oise N:Newton kgf s cm - : Engineering Unit (kgf second per squre centimeter : scl Also, to represent kinemticl viscosity of the fluid, use the eqution; γ= /ρ But ρis the density of the fluid. Some exmples of the viscosity coefficients for ir, wter, brke oil nd gsoline re shown in Tble.. Tble. Viscosity Coefficient of Gses nd Liquids Fluid Temperture Viscosity s Lek te Clcultion Using Vriety of Units of the Viscosity Coefficient (ressure: Absolute ressure ( Clcultion of Lek te in Compressive Fluid Using eqution., volumetric flow rtes of compressive fluid bsed on vriety of clcultions units re summrized in Tble.. Air Wter Brke Oil s s s s s s s s s s Gsoline s b c d Tble. Lek te of Compressive Fluid : (m; l: (m; : ( s;, : ( 3 (m / s : (cm; l: (cm; : ( s;, : ( (ml/ s : (cm; l: (cm; : (kg s/ cm ;, : (kg/ cm (ml/ s : (cm; l: (cm; : (= (ml/ s kg s/cm ;, : (kg/ cm Note: : dius of ipe, l: Length of ipe, : Viscosity of Fluid, : rimry Absolute ressure, : Secondry Absolute ressure

6 ( Clcultion of Lek te in Non-Compressive Fluid Using eqution.3, volumetric flow rtes of non-compressive fluid bsed on vriety of clcultion units re summrized in Tble.6 Tble.6 : (m; l: (m; w : ( s;, : ( Lek te of Non-compressive Fluid 3 (m /s ( w : (cm; l: (cm; w : ( s;, : ( b (ml/s ( w : (m; l: (cm; w : (kg s/cm ;, : (kg/cm c d (ml/s ( w : (cm; l: (cm; : ( kg s/cm ;, : (kg/cm (ml/s 3.80 ( w : dius of ipe, l: Length of ipe, w : Viscosity of Fluid, : rimry Absolute ressure, : Secondry Absolute ressure Lek te Conversion from Air to Liquid Using Tble. nd Tble.3 the lek rtes of wter, gsoline, nd brke oil in reference to ir re clculted, provided tht the sme test piece is used. The temperture of fluid is kept fixed t 0, nd the test pressure is kept t the sme level. The results re s shown Fig..3. Volume - Flow tio Mesuring Temperture : Constnt t 0 Wter Gsoline Brke oil rimry ressure kg/ cm Fig..3 Volumetric Flow te of Fluid eferred to Air 6

7 Clcultion of Orifice model =ε α A ( (-/ρ/ :Air volume flow rte ε:expnsion compenstion coefficient α:flow coefficient A:Are of the hole :Upwrd pressure bs :Downwrd pressure bs ρ:air density 7