Generate your gas standard from a liquid down to ppb levels
The LiqMix Cascade is a laboratory instrument designed for automatic generation of customized calibration gas mixtures by controlled evaporation of a liquid and future dynamic dilution/mixing with one or several gases. The system can generate a standard gas at different oncentrations down to trace levels in a programmed sequence with high precision, accurate and with full traceability.
Intelligent multi-stage cascade dilution offers very wide range of concentrations from % to ppb levels.
BENEFITS of LiqMix Cascade :
- Creating gas phase standards from a gas, liquid or liquid cocktail mixture
- Wide range of concentrations from % down to ppb generated on-site
- Complies to ISO 6145-7
- LiqMix software does all calculations and devices control even for very complex mixtures
- Build, save, run complex automated sequences of mixing/diluting
- Robust design, simple in use, fully automated operation
- Full automation of the process provides real time-saving for the operator
- Heated lines prevent condensation and maintain the vapors in gas phase till the delivery
- Can communicate with an analyzer via dry contact or TTL
The Windows based software is specially designed for the LiqMix Cascade. It continuously controls MFC's and other components of the system enabling an automatic generation of gas mixtures according to pre-programmed sequence. User defined automatic sequences may be saved and recalled at any time. A built in audit trail function ensures total traceability of each operation. The software controls the temperature set points for the evaporator and the heated lines to ensure that the newly generated gas standard is kept in a gaseous phase up to the delivery point. The LiqMix Cascade can be either remotely controlled, or drive an analyzer
Operation principle of LiqMix Cascade is based on the proven technology of Mass Flow Controllers (MFC) for gas and liquids. MFC are perfectly calibrated by Alytech and traceable to NIST. The system consists of two stages of dilution.
On the first stage a liquid delivered to a vaporizer with precise control by a Coriolis MFC that can handle any type of liquid or liquid mixture and not dependent on ambient conditions (pressure, temperature density, conductivity and viscosity).
The vaporizer is regulated at user-defined temperature. Injected liquid evaporates and diluted by a carrier gas and future trans ferred to a mixing chamber where it can be mixed or diluted again by up to 4 optional gas channels.
All interconnections and outlet line are heated in order to maintain the vapors in gas phase avoiding re-condensation till the delivery point. With a dilution ratio 104 the 100% gas or liquid can be diluted down to hundreds ppm from the 1st stage. If lower concentration is required, a part of the gas/vapor mixture sends to the second stage of the dilution, so-called Cascade. With cascade dilution, the LiqMix can deliver ppb level of components.
Rich remote control functionalities of the software and automated programmed sequences enable full automation by synchronizing the mixer/diluter with a gas chromatograph, pre-concentrator, spectrometer, gas analyzer or other system.
On-site creation of gas standards which are not commercially available in cylinders: siloxanes, BTX (benzene, toluene, xylenes), other organic solvents or liquid mixtures.
The system is used for linearity check and calibration of different detectors, analyzers like GC-PID, GC-PHID, GS-SCD, GC/MS and others application where gas phase standard is required.
Depending on the molar mass of the liquid substance the minimal achievable concentration can vary.
Initial concentration Final concentration Ethanol 100% 50 ppb mol Octane 100% 15 ppb mol Siloxane (D4) 100% 5 ppb mol
To go lower, liquid components can be mixed or diluted. For example, cocktail mixture of 10 solvents (equal parts) will result in approximately 10 times lower final concentration per component. LiqMix Cascade software does proper calculation even for complex mixtures.
1st stage dilution
Number of liquid channels: 1
Liquid MFC Coriolis technology, from 5g/h to 200 g/h FS
Liquids: Pure liquid or a liquid mixture (ex.: water, organic solvents) without precipitation, polymerization or salt formation (for specifics, please contact us)
Liquid flask (optional) should be pressurized by inert gas
Number of gas channels: up to 5
Inlet Gas pressure: stable and regulated within 3-8 bar
Gas compatibility: pure gases, concentrated gas mixtures, most of aggressive and reactive gases (for specifics, contact us)
Dilution ratio of the initial concentration on 1st stage: up to 1:10000
Accuracy: less than 2% all over the scale
2nd stage (Cascade)
Number of gas channels: 1
Dilution ratio of the initial concentration on 2nd stage: up to 1:10000
MFC operation range: 2 to 100% FS
Flow accuracy: ±0.5% of setpoint all over the scale
Repeatability: less than 0.1% of setpoint
Overall dilution ratio of 2 stages: up to 10^8
Heated output line length 1m in standard
Outlet Gas Pressure: atmospheric, higher pressure possible
Connectors: Swagelok 1/8”, other on request
Software: required PC with Windows 7 or higher, Ethernet port communicatio
Operation temperature: 10 – 50°C
Power supply: 90-260Vac, 1,5-4A, 50-60Hz
Dimensions: L x W x H 42x47x46 cm
Weight: approx. 35 kg (depends on configuration)
A fully inert version
compatible with most aggressive gases and active compounds like sulfurs, H2S, ammonia, VOC
A Liquid canister
1L stainless steel flask with support. Includes tubing with a tap and connection fittings