As part of C960 MFC Gas Mixing software the calibrations for each mass flow controller are supplied for specific gas.  Each mass flow controller has accuracy of 0.2% of full scale, or 0.8% of reading, whichever is greater.  The software provides a checking function for the set gas mixture.  This function looks for errors in the requested gas mixture.  The software will not execute the gas mixture in presence of errors.

Gas supplied to the chamber is sub-sampled for analysis by the gas analyzer. To control elevated target gas, the solenoid valve is attached to the outlet of a gas tank containing a high concentration of the target gas. When the concentration of the target gas falls below a user-defined threshold, a signal from the gas analyzer causes the A350 Gas Concentration Controller to open and target gas enters the gas stream and a mixing volume and combines with the major gas before entering the chamber. When target gas concentration in the chamber reaches the user-defined threshold, the solenoid valve is closed.

The same principal is used to regulate the target gas at sub-atmospheric levels in that target gas-free mixture is bled into the major gas stream if the target gas is exceeded.

The flow rate of target gas, entering the system can be controlled by a flow monitor and controller upstream of the solenoid valve. The concentration of the target gas can then be regulated slowly, or more rapidly, when it differs from the threshold level.

G400 Gas Mixing Systems

Key Features:

• Combine up to 9 gases using Qubit’s Mass Flow Controllers.
• Mass Flow Controller Ranges from 0.5 SCCM to +200 SLM.
• Mass Flow Controller accuracy 0.2 % full scale or 0.8% of reading.
• Multiple Alternate Gases may be used with each controller.
• 13 Different gas flow calibrations stored per controller.
• pure or mixed gases used as input gas.
• manual or software control of mixing.
• PC interface provided for software control.

Software:

• Combine 2 to 9 gases automatically.
• Instantaneous provision of required mixture with a mouse click.
• No calibration input required.Intuitive command structure.
• Automated flow implementation based on ratio and total flow.
• Error messages prevent selection out of range.
• Implement one gas mixture and queue the next.
• Store and retrieve settings.

Set up screen for 4 gas mixing system:

References:

• Charilaos Yiotis and Yiannis Manetas. Sinks for photosynthetic electron flow in green petioles and pedicels of Zantedeschia aethiopica: evidence for innately high photorespiration and cyclic electron flow rates. PLANTA Vol 232, Number 2, p523-531 (2010).

 The G262 Blow Off Valve is used to maintain a constant backpressure on the mass flow controllers and a Pressure Regulator, this results in providing a constant pressure to the common manifold. The Blow Off Pressure would be set somewhere above the Pressure Regulator’s level and a small amount of gas would be constantly blowing off or wasted. One would set the total mass flow controller  flow rate slightly above the total common manifold flow rates to maintain the G262 Blow Off and Pressure Regulator’s settings.

Mass Flow Controllers (MFC) are constant mass flow devices which will maintain a constant flow rate against changing or high backpressure. To set a constant flow through a device one can connect the output of one or more MFC directly to the device. If you want to set a flow rate to several devices, then you either utilize a MFC on each device or set up a manifold that delivers gas to several devices. Using multiple MFCs allows one to change the composition of the supply gas to a common manifold. If one is utilizing a common manifold and using needle valves or rotameters to set the flow through each device, a constant pressure is required at the manifold. The gas coming into the common manifold (a constant flow rate from one or more MFC) must be converted to a constant pressure behind each rotameter, otherwise if you change one rotameter, then all rotameters would be affected. G262 Blow Off Valve is used to achieve this constant pressure.

Specifications:

• display (characters, type): numbers, PSI, Kpa
• size (h/w/l) cm: 9.5/9.0/14.5
• weight (g): 450
• materials: aluminum base, plastic (black)

The G261 pressure regulator and gauge is essential in  accurate control of system gas pressure.  It ensures that flow rates set in the gas exchange system remain constant throughout experiments. Although Qubit’s software accounts for any variations in flow rate, setting and maintaining system pressure guarantees that sufficient gas is supplied to all sample chambers at the desired flow rate.

The G261 precision gas pressure regulator has a range of 0 to 15 psi. It may be used downstream of our high volume pumps or to regulate pressure downstream of a compressed gas source.

Specifications:

• display (characters, type): numbers, PSI, Kpa
• size (h/w/l) cm: 9.5/9.0/14.5
• weight (g): 450
• materials: aluminum base, plastic (black)

GENERAL FEATURES

• Oilless diaphragm unit
• Provides up to 32 L/min
• Motor Mounted
• Rugged construction/low maintenance
• Regulators included (up to 60 PSI)
• Carrying Handle
• Rubber Feet
• Mounted ON/OFF switch

Specifications:

• Motor Type:  Shaded Pole
• RPM (50 Hz): 1275
• Power Source:  230VAC (60Hz)
• HP:  1/8
• kW:  0.09
• Net Weight (kg):  7.3

GENERAL FEATURES

• Oil less diaphragm unit
• Provides up to 32 L/min
• Motor Mounted
• Rugged construction/low maintenance
• Regulators included (up to 60 PSI)
• Carrying Handle
• Rubber Feet
• Mounted ON/OFF switch

Specifications:

• Motor Type: Shaded Pole
• RPM (60 Hz):  1575
• Power Source:  115VAC (60Hz)
• HP: 1/8
• kW:  0.09
• Net Weight (kg): 7.3

Qubit Systems’ G900 DC Gas Pump provides total gas flow rates of up to 10 litres per minute at a system pressure of 5 psi. It may be used to provide gas to allow excellent control of flow to individual chambers via any of our gas flow controllers and monitors.

The G900 DC Gas Pump speed is varied by a front mounted potentiometer. Luer connectors provide easy connection of gas lines.

A power supply, tubing and a filter come with the G900 pump.

Lower volume pumps are available on request   Contact QUBIT with your specific request.

The P651 AC Gas Pump is used to provide gas through a gas exchange system at a measurable flow rate. The maximum unrestricted flow generated by the pump is approximately 4 LPM (at ~400mA). A potentiometer allows accurate control of pump speed with reduced risk of accidental alterations.

The P651 Gas Pump is extremely lightweight and has a compact design. Input and output gas ports are fitted with Luer-Lock connectors for easy attachment to the gas exchange system.

An adapter is supplied for use with an AC source, but the pump can be used in remote locations with the Qubit Systems’ A247 Battery Pack.

Specifications:

• power supply 12V, 1.25A
• size (h/w/l) cm 5.8/12.8/13.1
• weight (g) 500
• materials plastic (tan, black)

NOTE: THIS IS NOT A SUBMERSIBLE PUMP

The G265 Gas Flow Controller and Monitor is a cost-effective way to track continuous flow rates, within the range of 200 to 2 000 mL/min. Gas may be supplied to the unit’s stainless steel luer input port from either a pump or pressurized source.

The Flow monitor of the G265 is individually calibrated and measures the mass flow of gas.  Specific calibration values are provided for each unit.  The flow of gas can be controlled by adjusting it  manually with a stainless steel needle valve on the fornt of the instrument.

To monitor the flow of gas G265 needs to be used with a data acquisition interface (i.e. C410 LabPro,  C610 LabQuest Mini or other) and software such as C950 Customized Gas Exchange Software, C901 Logger Pro Software, or any other data acquisition software that accepts a 0 – 5 V analog signal.

Specifications:

• power supply: 12V DC, 500mA
• size (h/w/l) cm: 5.7/13.0/13.2
• weight (g): 420
• materials: plastic (tan, black)
• operating conditions (temp, RH) <25 PSI
• warranty: 1years