jasonsun
10-05-2007, 04:45 AM
hello, I am a new guy from China. My England colleage told me the forum was really well-known in refrigeration.
I have a question about the test method for filter filtration capability in ASHRAE Standard(ANSI/ASHRAE63.2-1996). In the segment 6.1, it says:"After the pump is started and the flow rate adjusted, the contaminant is added at the beginning of the three-minute flowing cycle.This length of time is sufficient to carry the contaminant to the filter under test.At the end of the three-minute period,record the pressure drop, stop the pump, and immedieately OPEN THE VENT VALVE.The permits air to enter the test apparatus and the lines to drain for one minute.At the end of this time,close the vent valve and restart the pump."
my question is why the vent valve shall be opened? to permit air into lines make sense?
Very appriciate for your reply.
I have a question about the test method for filter filtration capability in ASHRAE Standard(ANSI/ASHRAE63.2-1996). In the segment 6.1, it says:"After the pump is started and the flow rate adjusted, the contaminant is added at the beginning of the three-minute flowing cycle.This length of time is sufficient to carry the contaminant to the filter under test.At the end of the three-minute period,record the pressure drop, stop the pump, and immedieately OPEN THE VENT VALVE.The permits air to enter the test apparatus and the lines to drain for one minute.At the end of this time,close the vent valve and restart the pump."
my question is why the vent valve shall be opened? to permit air into lines make sense?
Very appriciate for your reply.