Results 1 to 6 of 6
Thread: Orifice Plates
-
17-07-2002, 11:47 AM #1
Senior Poster
- Join Date
- Feb 2001
- Location
- Doncaster, England
- Posts
- 199
- Rep Power
- 25
Orifice Plates
Can anyone give me some information on orifice plates, as a metering device, please?
Tony
-
17-07-2002, 03:19 PM #2
regular poster
- Join Date
- Mar 2001
- Location
- Derby, England
- Age
- 58
- Posts
- 86
- Rep Power
- 24
Tony
What info are you looking for specifically? Let me know and I'll try and help you out.
Frosty
-
17-07-2002, 07:31 PM #3
Senior Poster
- Join Date
- Feb 2001
- Location
- Doncaster, England
- Posts
- 199
- Rep Power
- 25
Any info really. Its just that I've never come across them.
What sort of systems would use them?
Why they would be used, as opposed to other metering devices?
How do they work- is it just like a capilliary tube?Tony
-
17-07-2002, 10:23 PM #4
VIP Poster
- Join Date
- Jun 2001
- Location
- N.Ireland
- Age
- 50
- Posts
- 1,630
- Rep Power
- 24
Tony, oriface plates can be used in replacement for electronic expansion valves on flooded systems. Usually used to meter liquid to evaporators in pairs, each equiped with a solinoide valve. One off pulse/bleed solinoid to keep the flow in the system moving and one on pulse/main to feed the main liquid to the evaporator and in some cases to over-feed the evaporator for liquid subcooling purposes. Switching of the main valve/oriface plate is by High Pressure Float switch, Low Pressure Float Switch or on the degree of liquid subcooling accross a heat exchanger, as in a Low Pressure Receiver System.
Other aplications for an oriface are oil metering on simple oil return lines from separators or small fixed load refrigeration coils where a means of separating liquid, such as an accumulator has been fitted (oil coolers and refrigerant purgers).
I hope this is of some help, post again if you require any clarification or just more information.
Regards. Andy.If you can't fix it leave it that no one else will:rolleyes:
-
18-07-2002, 01:43 AM #5
Moderator
- Join Date
- Mar 2001
- Location
- St. Louis, MO
- Posts
- 509
- Rep Power
- 24
The short tube orifices, aka, "plug" orifices, used in the majority of residential a/c and heat pump systems are essentially orifice plates. They are a precisely formed hole for refrigerant to flow thru. The flow equation for an orifice is:
m = C<sub>f</sub> * A * (2 * g<sub>c</sub> * <FONT FACE="Symbol">r</font> * <FONT FACE="Symbol">D</font>p)<sup>1/2</sup>
where:
m = refrigerant flow, lb<sub>m</sub>/sec
C<sub>f</sub> = flow coefficient
A = area of orifice, ft<sup>2</sup>
g<sub>c</sub> = gravitational conversion factor, 32.174 lb<sub>m</sub>-ft/lb<sub>f</sub>-sec<sup>2</sup>
<FONT FACE="Symbol">r</font> = refrigerant density, lb<sub>m</sub>/ft<sup>3</sup>
<FONT FACE="Symbol">D</font>p = pressure drop across the orifice, lb<sub>f</sub>/ft<sup>2</sup>Last edited by Prof Sporlan; 20-07-2002 at 03:27 AM.
Prof Sporlan
-
18-07-2002, 09:51 PM #6
Senior Poster
- Join Date
- Feb 2001
- Location
- Doncaster, England
- Posts
- 199
- Rep Power
- 25
Thanks Andy and Prof Sporlan.
Your help and information is much appreciated.Tony
Similar Threads
-
MP66 & Compressor Overheating
By Intermez in forum Technical DiscussionsReplies: 111Last Post: 13-04-2010, 08:58 PM -
Cold plates
By Peter_1 in forum CommercialReplies: 1Last Post: 10-05-2006, 07:52 PM -
Eutectic plates
By Temprite in forum CommercialReplies: 12Last Post: 31-05-2005, 12:13 PM -
superheat with the wrong orifice
By superheat in forum Air ConditioningReplies: 9Last Post: 25-10-2002, 08:54 PM -
Orifice
By reggie in forum FundamentalsReplies: 13Last Post: 11-10-2002, 10:56 AM
