Qubit’s Gas Control Systems operate to maintain a preset concentration of a gas such as CO2 or O2 in a chamber by injecting a known volume of the gas according to preset threshold levels. The system may employ up to two Mass Flow Controllers (MFC) for injection of selected gases. For example the system can control the levels of 13CO2 and 12CO2 in a chamber. The gas is re-circulated through the chamber, the system monitors the level of total gas of interest (i.e. CO2) and maintains it between user-defined limits (above ambient) by injecting 13CO2 and12CO2 at preset ratios.
Key component of the Gas Control System is the A360 Gas Control Module.
The Gas Control Module (A360) controls a subsampling pump which samples the gas from the chamber and carries it via a flow monitor at a preset flow rate to a gas analyzer (for example Q-S151 CO2 analyzer) . The analog signal from the gas analyzer and the Flow Monitor (Q-G266) are collected by the Gas Control Module and if the target gas concentration is below the preset levels the Gas Control Module turns on the MFCs for injection of the target gases into the chamber. The gas injected into the chamber is mixed by fans and measured periodically when the subsampling pump is activated. The output of the gas analyzer and the flow monitor are logged by a data acquisition interface and software.
The Gas Control Module (A360) calculates the gas injection period from the differntial between the upper threshold and the actual gas concentration measured by the gas analyzer. The design of the system avoids the possibility of overshooting the target gas concentration as may occur in systems that employ sollenoid controllers rather than mass flow controllers to inject gases.
Components of the Gas Control System:
- Gas Control Module (A360)
- Gas Analyzer (for example Q-S151)
- Gas Pump (Q-P651)
- Flow Monitor (Q-G266)
- Mass Flow Controler 1 (for example 13CO2)
- Mass Flow Controller 2 (for example 12CO2) (optional)
- Data Acquisition Interface
- Data Acquisition Software
Sample of Data Collected:
Qubit Systems can customize your Gas Control System to your specifications. Please contact us for details.