StoreX
Series
STX_V078.doc
51
CMa,
23.11.2009
An exhaust channels the surplus amount of gas to a defined point. The exhaust
is usually connected to the slightly under-pressurized exhaust system of the
building. The flow regulator is combined with a visual flow indicator and a scale
calibrated in l/min.
Open Loop System
The Open Loop System uses a more ntelligent system that limits gas flow to the
actual required amount. This solution is suitable for mid-accuracy applications
where the incubation chamber has to be filled with a specific gas or where a gas
has to displaced. In applications where a certain concentration has to be
maintained pre-mixed gases may be used. The advantage of this solution over
the continuous flow solution is its lower gas consumption while still maintaining
low costs.
The picture below explains the functioning of this system. At the gas inlet a
pressure limiter and a flow limiter protect the system from inlet pressure
fluctuations. This also makes the system relatively insensitive to the amount of
input pressure.
The actual gas flow is controlled by a solenoid. The solenoid is controlled by the
main CPU. By sensing both, glass door switch and Gate switch, the CPU knows
when there is a user access or when the Gate is opened and reacts accordingly.
In fact the CPU holds three values that represent the gas needed to add. The
standby value maintains the gas concentration when there is no access and
compensates for minor leakages of the incubation chamber. The Gate Access
Value compensates the gas loss caused by a Gate access while the User Access
Constant allows recovery after opening the glass door. The CPU internally
calculates the actual amount of gas needed in a specific situation. Since this
system limits the gas consumption to a fairly low level the exhaust does not have
to be connected in most cases.
Pressure
Limiter
Gas Inlet
Flow Limiter
Incubation
Chamber
Main CPU
Exhaust
Flow Regulator
Gate Switch
Glass Door Switch
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
