Ch. 12 Ch. 12 Filter Installation Leak Testing Filter Installation Leak Testing

HEPA test HEPA test

Manufacturer's factory and packed Manufacturer's factory and packed OKOK

Unpacked and fitted into the filter housingsUnpacked and fitted into the filter housings maybe damage maybe damage

Leakage problems Leakage problems – casingcasing– housinghousing

Testing : artificial test aerosol Testing : artificial test aerosol

Leakage areas in a HEPA filter

A - filter paper-to-case cement area C- gasketD - frame joints. B - filter paper (often at the paper fold)

Gasket leaks from filters inserted down from ceiling

Gasket and casing leaks from filter inserted up from cleanroom

Figure 12.4 Filter-housing gel seal method

Artificial Smoke and Particle Test Artificial Smoke and Particle Test

Cold-generated oilsCold-generated oils– Di-octyl phthalate (DOP)Di-octyl phthalate (DOP) 鄰苯二甲酸二辛酯鄰苯二甲酸二辛酯

oily liquid, potentially toxic effects, no longer used oily liquid, potentially toxic effects, no longer used

– Di-octylsebacate (DOS)Di-octylsebacate (DOS) 葵二酸二辛酯葵二酸二辛酯常用常用

– poly alpha olefin (PAO)poly alpha olefin (PAO) 聚烯茎油 聚烯茎油 常用常用

Cold-generated oil Test Cold-generated oil Test

Laskin nozzleair (high pressure)

oil

Air+oil particle

0.5 m

Air pump

Hot generated smokesHot generated smokes

Evaporation chamber

inert gas: CO2

oil

oil smoke

aerosol

condense

vaporize

0.3 m

Hot oil smoke generator

Semiconductor manufacturing Semiconductor manufacturing

'outgassing' 'outgassing'

chemical products harmful to filter chemical products harmful to filter

使用使用 Polystyrene Latex Spheres (PLSs)Polystyrene Latex Spheres (PLSs)

聚苯乙烯乳膠球聚苯乙烯乳膠球 (0.1 ~ 1(0.1 ~ 1m)m)

Apparatus for Measuring Smoke Apparatus for Measuring Smoke PenetrationPenetration

PhotometerPhotometer 光度計光度計– 28 1/min (1 ft3/min) of airbor28 1/min (1 ft3/min) of airbor

ne particles ne particles – particles refract the light particles refract the light – electrical signalelectrical signal– concentration: between 0.00concentration: between 0.00

01 μg/1 and 100 μg/1. 01 μg/1 and 100 μg/1.

Single particle countSingle particle countersers– sample a volume of aisample a volume of ai

r and this is collected r and this is collected in a set timein a set time

Methods of Testing Filters and Methods of Testing Filters and Filter HousingsFilter Housings

Scanning methodsScanning methods– a probe with a photometer, or single particle a probe with a photometer, or single particle

counter, counter, – Scan speed : not more than 5cm/sScan speed : not more than 5cm/s– leaks : media, filter case, its housing leaks : media, filter case, its housing – The most common leaks: The most common leaks:

around the periphery of the filteraround the periphery of the filter

the casing-to-housing seal, the casing-to-housing seal,

the casing jointsthe casing joints

Repair of leaksRepair of leaks

Filter media leak Filter media leak – at the fold of the paper at the fold of the paper – repaired on site with repaired on site with

silicon silicon

replacedreplaced