Production and Delivery of CO2 for Instrumental Insemination
|Pressure regulators that are intended for compressed air operation are also OK for use with CO2. They may be purchased new from pneumatics supply houses or as in my case I scrounged a second hand one from a local packaging machine manufacturer. The one illustrated at right has a plastic body, but is almost identical to the diecast metal one that is of Norgren manufacture.|
|Woulff's Bottles, developed by a British chemist, Peter Woulfe in 1767, who used a bottle with two separate necks (f or ff in spelling seem to be both used). Also known as bubble bottles, they can be used as a delivery rate monitor and to remove any unwanted contaminants from the carbon dioxide itself by use of suitable liquids in the body of the bottle. The direction of flow is indicated by the arrows. Bubble rate always seems to be stated at one per second, but the actual delivery rate at that frequency will depend on the diameter of the tubing at the point the bubble forms.|
Final rate limiters... Small flow rate limiters or adjusters
are available from aquarium suppliers and are intended to regulate the
amount of oxygenation bubbles in a fish tank. Made of plastic these
are inexpensive. The one illustrated at right has a base 19.5 mm
x 24.5 mm and 5 mm diameter nipples. Regulation is achieved
by a tapered needle that can be inserted or withdrawn by the action of
the knurled cap which engages the threaded portion of the valve body.
If a piece of soft plastic tubing is used in parts of the system a
crude, but effective, method of regulating the bubble rate is to
place a carpenter's "G" clamp ("C" cramp) in such
a way as to flatten the plastic tube. This is similar in action to a
"Mohr clip" that can be used on rubber tubing in the
The triple bank version shown at left can be pulled to pieces and any number can be banked together. These valves can be stuck down to a flat surface using double sided sticky pads.
The CO2 gas may be transported around your
bench top, using soft plastic tubing that is also available from
aquarium suppliers and is only a few pennies or cents per metre.
The aquarium suppliers reference it a 6 mm tubing, because they use the external dimension, the bore is a nominal 4 mm diameter and will fit on the nipples and adaptors illustrated on this page.
The plastic tube can be joined together and angles
negotiated by small plastic adaptors and "T" pieces. These
are also available from the aquarium supply shops. The package that they come in is illustrated at right and a close up of the individual items is shown below
Written...24 October 2001, Revised... 31 December 2001, Revised... 13 August 2003, Additions... 11 October 2003,