Gas operation for desiccators or incubators
Incubators may be trickle fed with CO? for maintaining pH levels in tissue cultures. Desiccators use the same physical arrangement with industrial dry nitrogen for a dust-free and very low humidity environment within the chamber.
Incubators and desiccators are available with these gas fittings as an optional extra. The inlet is a tube fitting and the outlet a ball valve. This allows for trickling of gas through the chamber. Our catalogue item EDCG is required for this factory installation which must be specified when ordering an incubator or any one of the EDC drying cabinets.
Connection recommendations: An industrial dry nitrogen (or CO?) cylinder should be equipped with a two-stage regulator, with the second stage adjusted so that an outlet tube (immersed in water) would just run a continuous stream of gas. Rather than a needle valve, we recommend the use of a small additional regulator - regulator EM060, without gauge. This regulator should be adjusted to expel about one bubble per second or less. That flow rate to the cabinet (or incubator) is sufficient for maintaining pH or dry atmosphere, depending on use. A 'G' size gas cylinder may last for many months.
It may also be desirable to install a by-pass around the second regulator. This would consist of a two-way valve to supply gas either to the small single stage valve or bypassing that and re-connecting to the line after the small single stage regulator, with a simple "Y" or "T" tube fitting. This bypass would allow purging the cabinet, when required, with a larger dose of gas.
Leak testing: The system operates under very low pressure and leaks may be a problem only because the cylinder remains open. Over months some gas may be lost if the system is not tight between the two-stage regulator and the outlet of the additional small regulator. To test for leaks, make up a few mL of a 10% detergent solution. Work the solution with a small paintbrush to form a bubble solution. Paint the solution onto suspect connections and small leaks will become obvious.