Bronkhorst Vapour Flow Controllers

Bronkhorst has a unique and patented ‘CEM’ technology, which stands for Controlled Evaporation Mixing, is developed for accurate vapour flow control. Traditional bubbler systems are often not capable of handling sufficient quantities of liquid with a low vapour pressure, or perform in an imperfect way. Moreover, they cannot instantaneously provide vapour of a mixture of liquids with different vapour pressures. These issues are overcome with Bronkhorst vapour delivery solutions.

Bronkhorst’s evaporation technology is fast, accurate, highly repeatable and efficient.

At room temperature the liquid (precursor fluid for chemical reactions or water for humidification purposes) is drawn from a container with an inert gas blanket, or membrane, and measured by a liquid mass flow meter. The required flow rate is controlled to the setpoint value by a control valve (C) forming an integral part of the patented liquid flow and carrier gas mixing valve (M). The then formed mixture is subsequently led into the evaporator to achieve total evaporation (E).

CEM: Controlled Evaporation Mixing

  1. Fast evaporation
  2. Precursor only short period of time at higher temperature
  3. Well-suited for less stable precursors
  4. Pressure and temperature in piping are of no importance
  5. Precursor dosing via liquid flow controller
  6. Precursor in a container at low temperature



CEM-Technology: Controlled Evaporation Mixing
The CEM-System (Controlled Evaporation and Mixing) is an innovative Liquid Delivery System (LDS) that can be applied for atmospheric or vacuum processes. The vapor generation system consists of a (thermal or Coriolis) liquid flow controller, an MFC for carrier gas and a temperature controlled mixing and evaporation device. The system is suitable for mixing liquid flows of 0,25-1200 g/h resulting in saturated vapor flows of 50 mln/min up to 100 ln/min. This vaporizer system can replace bubblers. New opportunities created with the CEM-system: mixtures can be evaporated and even solids, dissolved in solvents can be vaporised successfully.


  • accurately controlled gas/liquid mixture
  • fast response
  • high reproduceability
  • very stable vapour flow
  • flexible selection of gas/liquid ratio
  • lower working temperature than conventional systems
  • optional control by PC/PLC (RS232/fieldbus)

VDM-Series: Vapour Delivery Modules
Based on the CEM-technology as described above, Bronkhorst designed a new series of Vapour Delivery Modules. These compact sub-systems incorporate the components of the CEM-System and more! Besides gas and liquid flow controllers and the temperature controlled evaporator, the VDM-Series feature integrated power supply with display (1.8” TFT) and control functions. As an option, the unit offers local or remote trace heating temperature control. The compact, ‘plug and work’ module can generate (saturated) vapour flows within the range of 100 mln/min up to 10 ln/min. It can be applied for atmospheric or vacuum processes and is capable of evaporating mixtures and even solids, dissolved in solvents.

Additional features (compared to separate CEM system components)

  • No need for engineering or manufacturing
  • Pre-tested, safe and ready to use
  • Readout/Control panel, incl. 1,8” TFT display, alarm/signaling and counter functions.
  • Integrated fieldbus interface (option)

Vapour Control Applications

  • CVD (Chemical Vapour Deposition), e.g. for hardening, thin film coating or planarization processes
  • Testing/calibration of analyzers with reference gas vapour concentrations
  • Toxic gas effects on protective clothing
  • Analyzers with reference H2O vapour concentrations
  • Humidification of fuels
  • Anaesthetics
  • Sorption experiments or processes in pharma or food applications

Success Stories

Additional information

Weight 3.75 oz
Dimensions 12.40 × 3.15 × 2.37 in