- Glass bubbler systems have been widely used across manufacturing and research processes to generate vapor streams.
- Compared to glass bubblers, Controlled Evaporation Mixers, or CEMs, improve process accuracy, repeatability, and control.
- In addition to improving vapor generation and control capabilities, CEM Vapor Generation Systems offer remote access, data logging, and analytical tracking.
Vapor streams for manufacturing processes and research purposes are often created using a glass bubbler system. There are many household items that can create a bubbler system, but an advanced bubbler will cost thousands of dollars. When using corrosion resistant tubing, bubblers do offer the advantage of being able to vaporize very corrosive fluids. And while it does offer this advantage, it also has a list of disadvantages in comparison to vapor generation systems that rely on a Controlled Evaporation Mixer, or CEM.
Traditional Glass Bubbler System Diagram
What is Controlled Evaporation Mixing?
The CEM System is a vapor delivery system that is useful for both atmospheric and vacuum processes. This type of vapor generation system relies on a (Thermal or Coriolis) liquid flow controller, a mass flow controller for carrier gas, and a temperature control, mixing, and evaporation device, or CEM.
Features:
- accurate control of the gas/liquid mixture
- fast response
- high reproducibility
- very stable vapor flow
- flexible selection of gas/liquid ratio
- lower working temperature than conventional systems
- control via Vapor Generation System Controller
Bubbler vs CEM Vapor Generation System
Advantages of a Controlled Evaporation Mixing (CEM) System vs Bubblers:
The advantages of using a CEM instead of a traditional bubbler system are clear. Using a CEM system will save you money, increase operational efficiency, increase accuracy, and increase reproducibility.
- fast evaporation precursor only short period of time at higher temperature
- well-suited for less stable precursors
- pressure and temperature in piping are of no importance
- precursor dosing via liquid flow controller
- precursor in a container at low temperature
Components of a CEM Vapor Generation System
(CEM) Evaporator
The Controlled Evaporator Mixer (CEM) is an all-in-one vaporizer, mixing chamber, and vapor control device. It’s the most critical component in a Vapor Generation System.
- accurate control of gas/liquid mixtures
- fast response
- high reproducibility
- very stable vapor flow
EL-Flow Select
The EL-FLOW Select is a thermal mass flow meter for gases. It offers a modular design that allows the control valve to be removed or replaced with ease. Thus, it improves process flexibility.
- high accuracy
- fast response, excellent repeatability
- optional multi fluid / multi range functionality
- virtually pressure and temperature independent
- compact design
Mini CORI-FLOW
The Mini CORI-FLOW offers a sensor that relies on Coriolis technology to measure flow rates. Contrary to many other Coriolis flow meters on the market, the mini CORI-FLOW Series offers integrated PID control and close-coupled control valves or pumps, thus constituting very compact, cost and space-saving, precise Coriolis Mass Flow Controllers for low flow liquid and gas regulation.
- high accuracy, excellent repeatability
- fast response
- independent of fluid properties
- additional density and temperature output
- compact, rugged (IP65) design
- optional ATEX approval Cat.3, Zone 2
CEM Vapor Generation Controller
The CEM Vapor Generation Controller connects all the above components and allows users to control each component as a single, integrated system. Available in rack-mounted or desktop models, our Vapor Generation Systems enable superior control of vapor streams and offers functions such as totalizer, continuous operation, heat tracing, and more. Best of all, it’s ethernet enabled so protocols such as Modbus can be used for remote access and analytical tracking.
