Mobilee Air Co
onditiooning Hoses
HDESCRIPTIOON OF TECH NICAL CHALLLENGE

State-of-the-aart MAC hose
es aretested for lea
ak rates in the range of2 – 5 g/a loss
s of refrigerant.

The well-know
wn refrigerant R134a will bee banned as a highly climatee-damaging fluorinatedgreenhouse gas.
gReplacem
ments include R1234yf, whicch, unfortunateely is classifie
ed asextremely flammmable and aalso reacts when heated to formfhighly coorrosive hydroffluoric acid.
R1234yf also is by far moree expensive thhan R134a. Bo
oth of those faactors are prom
mptingmanufacturers to calculate a lower reserv
ve of refrigera
ant for their sysstems, which in turn,increases the leak rate requuirements.
Standard AC hoses consistt of flexible tub
bing with alum
minum connecttors on both ends
etoconnect to othher componen
nts of the AC circuit.
cIn receent times, Inteernal Heat Excchanger (IHX)
hoses push onto the markeet. An IHX hos
se is an AC ho
ose with a buildd-in heat exch
hanger. In theIHX hose, twoo air condition ing lines run in contra flow tot each other exchanging heat between
one inner andd one outer pip
pe. It uses thee cold vapor fro
om the evapoorator to cool th
he hot liquid
before it enters the expans ion device, resulting in incre
eased cooling . The amount of energy
used by the aira conditioningg system can be reduced byy taking advanntage of the inncreasedcooling. This results in incre
eased fuel eco
onomy and reduced emissioons.

In an IHX hose, two air connditioningcflow to eeach otherlines run in contraexchanging heat
hbetween an innerand an outerr pipe and therrefore
need to be teested more inttensively.

Currently, mo
ost AC system s are tested fo
or a leak rate of 2 - 7 g/a of refrigerant coorresponding
to a helium leak rate in the range of 10-5 mbar∙l/s. Mos
st air conditionning componen
nts arecurrently teste
ed for leak rate
es in the orde
er of 10-4 to 10-5 mbar∙l/s, buut leak rate req
quirement mayy
become moree stringent withh the ongoing introduction ofo R1234yf

THE INFICON SOLUTIONNLeak testing standard AC
C hoses in component prooduction
Cllam shell testing

Vaacuum chambber testingThroughput

MediumHigh

Investment

MediumHighLoocalizing methhod

Integral meethod,leak needs to be loocalized later

Integral / Locaalizing

Comparison ofo leak testingg methods for componentcprroduction

LEAK TESTIN G OF COMPONENTS
MOBILE AIR CO NDITIONING HOSES

In a clam sh ell system, small clamps area placed arouund the conne
ectors to betested. The A
AC hose is theen evacuated anda pressurizeed with heliumm. If theconnection iss leaky, the heelium concentrration inside thhe clam shell willw increase.
The Protec PP3000(XL) Hellium Leak Detector is then cconnected to thet clams andddraws a sam ple from the innner volume ofo the clam sheell. If helium iss present in
the sample, iit is then detec
cted by the Wise Technologgy helium senssor inside theProtec P30000(XL). The hig
gh flow of the Protec P30000(XL) offers soome uniquebenefits for cclam shell testing as its high flow allows foor all clam sheells to beaneously. Onlly when a leaktested simulta
k is detected w
will the test sysstem
sequence thrrough the indiv
vidual clams anda locate whiich connectionn is leaking.
AC hoses arre tested with multiplexer cllam shellsystems, allo
owing to locatte the leak if th
he hose isfound leaky in one test seet-up.

With this testting method, the integrity of the hose itsellf is not testedd.

For higher thhroughput, thee complete AC
C hose can be tested in a va
acuum
or this testing process, the hose is sealedd at its ends beforeb
testing.
chamber. Foamber lid is cllosed, vacuumOnce the cha
m pumps pull a vacuum. Thee AC hoseand the chammber are evac
cuated simultaaneously; subssequently the AC hose isbackfilled witth helium. Heelium then hass the opportunnity to migrate outwards anddif a leak is prresent, the INFICON LDS30000 Helium Leeak Detector (which(ishe vacuum pu
valved into th
umps after thee part has beenn filled with heelium) detects
the helium aatoms as they emerge from the AC hose.
With this tessting method, however,
han additional
atesti ng step is required to locateethe leaks in ffaulty subasse
emblies for subsequent repaair.

AC hoses arre tested in vaacuum chambe
ers withhigh throughhput.
Leak testing IHX hoses inn component production
IHX hoses aree typically testted in vacuum
m chamber syystems with aan LDS3000 HeliumH
Leak
Detector . If th
hey have interrnal brazing/ welds,w
the test consists of tw
wo phases:
1. Testing the internal inte
egrity of the hose,hi.e. check if refrigerantt from one tub
be can leakinto the otherotube by oonly charging one line with helium
hand deetecting its miggration intothe otherr.
2. Testing the integrity off the hose to th
he outside, i.e. check if refriggerant may leeak to theb charging bo
oth lines with helium
hand detect the preseence of helium
m in theoutside byvacuum chamber.
cBENEFITS OFO LEAK TES
STING AC HO
OSES WITH TRACERTGAAS


ble measurements for reliab
ble results of leeak testing
Accurate and repeatab
he smallest leaaks
High sensitivity leak te sting to find th
p process to d
detect leaks ea
arly in the prod
duction processs
Multi-step

For more innformation, please visitt us at www
w.inficonautoomotive.comm®

w w w .i n f i c o n .c o mr ea c h u s@ i n f i co n . c o m

Duue to our continuing pprogram of product im
mprovements, speciffications are subject tto change without nootice.
miaj00en-a (1606)©2©2016 INFICON