6 Old Ways to Generate Vapor Versus 1 New Way!

Generating vapor is a perfect example of how technology development in one are can benefit multiple industries. By combing the accuracy and digital performance of modern mass flow metering and control technology, alongside temperature control you can control the properties of vapor as never before.

Vapor production has always been a necessary, but complex and expensive process. There have been multiple methods employed to achieve the dispersion of liquid into a gas phase. The variety of methods used is a reflection of the bespoke approach taken by many to compensate for the lack of awareness of a commercially viable solution. Some of the examples that we have come across:

1. Dew-point generator (bubbler system)
2. Mixed-flow Generator
3. Static method of humidity generation
4. Two-pressure process
5. Two-temperature process
6. Saturated salt solutions

Each of these methods have been developed to control the concentration (volume per volume) of liquid in gas to achieve the desired end result.

What is the end goal?

There are many industries that need or would benefit from vapor generation to achieve their end goal. We have been talking to biomedical researches, technical fabric manufacturers, glass coating companies, catalysis research & development, graphene research & development and bulk food packaging machine manufacturers.

There are, as always, a few common themes among each of the people that we speak to. In application development the drive is always to increase or decrease something, it could be ; cost, waste, yield or raw materials. Almost anything associated with an application will either have an increase or decrease requirement.

How do we achieve our goal?

Multiple factors can be improved by installing a Bronkhorst® Controlled Evaporating Mixing system (CEM) or Vapor Deliver Module (VDM) in your installation, these include:

• Speed of response to process changes
• Reduced raw materials costs
• Accurate temperature control
• Quick turnaround on substrate
• Choice of parts per million, parts per billion, mole or concentration output conditions.

How does the Bronkhorst Controlled Evaporating Mixing system (CEM) or Vapor Delivery Module (VDM) system achieve these things?

Vapor is generated through the addition of a liquid into a gaseous stream, usually under temperature. We add control to each of the inputs, thereby acquiring control of the output. If we take the first example from the list at the beginning of this blog, Dew-point generation, then we can see:

• Evaporation of the fluid can cause concentration changes in vapor
• Differences in back pressure created by changing fluid levels
• Flow rate changes with fluid level resulting in changing process conditions
• Variations in thermostat accuracy can add temperature variations to the fluid
• High energy consumption from heating a fluid bed

By removing those sources of variation from the input, combining liquid flow control with a Coriolis mass flow meter (MFM) and gas flow control with thermal by-pass mass flow controller (MFC) with a temperature controlled flow path you can better predict the conditions of the resultant vapor. Once an output has been achieved with a known input combination, it can be replicated repeatably.

For example, in the picture below we know that the input conditions entered will achieve the desired process conditions, that level of control is not available in the other process.

With direct control of the liquid and gas flows into a temperature controlled flow path it is easy to change the input conditions and predict consistent process conditions. The Coriolis liquid mass flow meter and thermal by-pass gas flow controller are directly linked to a 3-way mixing valve on top of a temperature controlled flow path. By passing the liquid and gas through the valve orifice the combined flow is aerosolized before being heated and this ensures complete vaporization of the liquid in the gas stream.

Taking this a stage further, if you have a specific composition in mind then check out our online free to use database called Fluidat, go to www.fluidat.com register and you can check out yourself what is possible.

Looking at the 6 old ways and 1 new, the innovation and thought that has gone into the original and still used old methods of vapor generation is clear. However the beauty of society is that we can learn from one another when another technology is available.