[V8] Another AC question

Scott Phillips Scottp at ippe.com
Sat Jul 19 19:01:14 PDT 2008


a orifice tube is exactly what it sounds like. It is a restriction point
that is placed in front of the evaporator. On one side of the O tube is
"high pressure" , the other is low pressure. The change in pressure is
akin to you puckering up and whistling. Inside your mouth, is high
pressure, your lips is the orifice and then beyond is low
pressure...notice when you whistle like that your lips get cold? .. same
deal with the AC system, the compressor.. compresses the Freon and the
orifice tube "releases" that pressure in the form of "cold".. that cold
is a thermal transfer. The cold is transferred to the aluminum of the
evaporator where air passes by it and (1st law of thermal
dynamics..entropy) becomes cold.. further down that line is the suction
side of the AC compressor that starts the process over again.. 

Hope that sheds some light on it for you. You may find things out there
called a varying venture orifice tube.. they are supposed to be better
in a hotter climate (to replace the orifice tube); from what the AC guys
I talk to say about them, none have given me enough reason to put one in
the car.

Oh yeah!..Be sure to put it back in, in the right direction!.. 

Good Luck


-----Original Message-----
From: Ed Kellock [mailto:ekellock at gmail.com] 
Sent: Saturday, July 19, 2008 8:23 PM
To: Scott Phillips
Subject: RE: [V8] Another AC question

Cool.  I was thinking orifice tube for some reason even though I have no
idea what it is.  But it just sounded right.  Strange.


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