CO2 set up

Carbon dioxide (CO₂) has long been used as an attractant in mosquito traps. Traditionally, the CO₂ has been in the form of solid dry ice. However, supply of dry ice on a regular basis, particularly in remote regions, may not be possible. This can be overcome by utilising CO₂ from gas cylinders and having the gas flow controlled by a Regulator in conjunction with a Microregulator.

Microregulator & couplings	Brass Adapter	Hose Connecter	Regulator
Food Grade CO₂ Cylinder (This is a large "G" size cylinder, but the smaller "E" or "D" sizes are lighter and more portable).	Silicon Tubing 5mm internal diameter	Teflon Tape	Tools (wrench, knife, bucket, measuring cylinder)

	1. Remove outlet connection from the Regulator. Note this is held in by Loctite* and requires considerable force to break the seal. Unscrew nut anticlockwise. (Loctite is a liquid applied to threads in order to lock the screw/bolt/nut in place).
	2. Wrap 4-5 layers of Teflon Tape around the thread of the Brass Adapter. This provides for a better gas seal. (Teflon Tape, also known as Plumber's tape, can be purchased from any hardware store).
	3. Screw the Brass Adapter with teflon tape into the outlet of the Regulator and tighten firmly.
	4. Connect Microregulator to the Brass Adapter. Note the order and direction of the brass locking washers. Note also that the direction of the arrow on the Microregulator (which can't be seen in this image) must be pointing away from the locking washers - the arrow must point to the hose connector for proper gas flow.
	4a. Place conical brass locking washer into the Microregulator, narrow side in (this is the only way it will go).
	4b. Place ring brass locking washer next in line, ensuring the narrowest end is closest to the Microregulator.
	4c. Screw nut on, but not tightly.
	4d. Insert the non-barbed end of the Brass Adapter into the nut. This will be loose until the nut is tightened, which deforms the brass locking washers thereby permanently locking the Microregulator onto the Brass Adapter. Tighten nut.
	5a. Connect Microregulator to the Hose Connector, ensuring that brass locking washers are placed in the same order and direction as above. Note from this angle, the arrow on the Microregulator should not be seen.
	5b. The Microregulator viewed from the opposite side to 5a, indicating that the arrow is pointing to the Hose Connector and hence the Microregulator is positioned correctly.

The aim of calibrating the Microregulator/Regulator set-up is to establish a CO₂ flow rate of 300mls/minute. Ideally this should be done before the start of each season and at least once during the season.

	1. Attach Microregulator/Regulator set-up to the gas cylinder and tighten firmly.
	2. Attach the required length of hose to the Hose Connector on the Microregulator. (You may wish to put a cable tie on the hose to hold it more securely).
	3. Fill bucket with water, and completely fill the cylinder with water, right to the top. (Note you can use anything container that can hold at least 300mls).
	4. Place hand across the top of the cylinder, invert and place into bucket, ensuring no air enters the cylinder.
	5. Turn gas on at bottle. Note only the right gauge should register.
	6. Turn Regulator on and adjust until left gauge reads 100 kPa. Adjust Microregulator down to minimum flow rate by turning adjusting dial clockwise.
	7. Place the other end of the hose up into the cylinder and allow gas to bubble into the cylinder. Time the period for the gas to displace 300mls of water - the aim is for 1 minute. Increase gas flow by adjusting Microregulator valve anticlockwise. Refill cylinder and repeat this step until desired flow rate is achieved. This may take several attempts.
	8. Place some tape over the Microregulator valve to prevent accidental adjustment.

Microregulator Cat. no.: B-SS4 Price/unit: $96.60	Brass Adapter Cat. no.: B-4-TA-1-4RT Price/unit: $3.10	Hose Connecter Cat. no.: B-4-HC-A-401 price per unit: $6.40	Regulator Part no.: 301681 Price/unit:$134.56
Suppliers: Swagelok Eastern Australia Unit4/105a Vanessa Street Kingsgrove NSW 2208 Phone: (61)(2) 9554 4040 Fax: (61)(2) 9554 4030 or: Brisbane Valve & Fittings 12 Thompson St BOWEN HILLS QLD 4006 Ph: 07 3252 8900	Suppliers: Swagelok Eastern Australia Unit4/105a Vanessa Street Kingsgrove NSW 2208 Phone: (61)(2) 9554 4040 Fax: (61)(2) 9554 4030 or: Brisbane Valve & Fittings 12 Thompson St BOWEN HILLS QLD 4006 Ph: 07 3252 8900	Suppliers: Swagelok Eastern Australia Unit4/105a Vanessa Street Kingsgrove NSW 2208 Phone: (61)(2) 9554 4040 Fax: (61)(2) 9554 4030 or: Brisbane Valve & Fittings 12 Thompson St BOWEN HILLS QLD 4006 Ph: 07 3252 8900	Supplier: BOC Gases Australia Fax: 132427 Ph: 131262 (also for Gas Cylinders)

	1. Place motor unit/catch bucket into position, with CO₂ set-up. Ensure cylinder is secure in its position.
	2. Attach hose to chain around 10-15cm above the motor unit. Turn on Cylinder and Regulator (adjust Regulator to 100kPa) and catch those mossies! (Tips: Place a bin lid over the motor to stop rain wetting captured mossies, grease chain with vaseline to hinder ants).