Table of Contents
Cloud Condensation Nuclei Counter (CCNC)
Manufacturer: Droplet Measurement Technologies
Description
Continuous flow, single supersaturation instrument that used a longitudinal thermal gradient to measure cloud condensation nuclei.
Mounting Location
Interial (19“ Rack)
Air Sampling Location
Aerosol Inlet
Instrument Requirements
Power: 15 Amps at 28 Volts DC [Source: Don Collins]
Weigth: 28 Kg [Source: Don Collins]
Size: width - 17 inch. Height - 30 inch. Depth - 12 inch. [Source: Don Collins]
Data Collection
Data is stored in the C:\CCN data directory. All files are saved as .csv files. While data can be stored in the CCNC while being collected, data should be moved out of the CNCC computer with the use of an external usb drive or through the use of remote desktop.
A separate computer can be connected to the CCNC through remote desktop. To connect, the IP address of the CCNC must be known. Additionally, the connection also requires a username and password, which is stated by the manual to be “CCN\Administrator” and “password”, respectively.
Performance Checks
Periodic Leak test performed on the CCNC to check the rate of leaking.
In order to perform the leak test, a vacuum pump and a stopwatch are required.
- Connect the vacuum pump to whichever air port you desire to test. Secure tightly to prevent any leaking from the pump.
- Use the vacuum pump to exert 10 inches of mercury (approximately 339 millibars) and start the stopwatch.
- After 10 minutes have elapsed, check the time and the pressure reading on the vacuum pump.
- For this laboratory, the acceptable limit is 1 inch of mercury every 10 minutes.
| Date | CCNC Model | S/N | Test point | Time | Pressure Change (inches of mercury) |
|---|---|---|---|---|---|
| June 7, 2017 | 100 | 076 | Inlet | 00:12:33 | 10” to 9.6“ |
| June 7, 2017 | 100 | 076 | Inlet | 00:12:13 | 10” to 9.7“ |
| June 7, 2017 | 100 | 076 | Exhaust | 00:12:03 | 10” to 8“ |
| June 8, 2017 | 100 | 076 | Exhaust | 00:10:02 | 10” to 8.2“ |
| June 8, 2017 | 200 | 024 | Inlet A | 00:10:04 | 10” to 9.5“ |
| June 8, 2017 | 200 | 024 | Inlet A | 00:10:27 | 10” to 9.7“ |
| June 8, 2017 | 200 | 024 | Inlet B | 00:01:56 | 10” to 1.0“ |
| June 8, 2017 | 200 | 024 | Inlet B | 00:01:55 | 10” to 1.0“ |
| June 8, 2017 | 200 | 024 | Exhaust | 00:10:01 | 10” to 8.7“ |
| June 8, 2017 | 200 | 024 | Exhaust | 00:10:02 | 10” to 8.5“ |
Troubleshooting
- June 19, 2017: CCNC Optic was found to be extremely flooded and fogged up with condensation. Various steps were taken to solve the problem. The optic diffuser was removed and water inside the optic chamber was removed with compressed air. Additionally, the water line going from the optic to the water trap was found to be full of water. The line was cleared with air. Finally, the optic water pump was set to 2 second activation interval instead of 16 seconds. The CCNC was then set to run with the water supply pump shut off for 30 minutes.
Picture
See picture on Droplet Measurement Technologies Web site.
