Question: During what year was the idea of the evaporator first conceived?
About the article "Maple syrup", section "Modern era".

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  Heidolph Rotary Evaporators can be seen in newly released blockbusters such as the 2012 comedy "The 5 Year Engagement" and 2012 epic comic based movie "The Avengers" during the lab scene on the ship.
Heidolph Laborota evaporator and Modular concept shaker was shown several times in the 2009 Sci- Fi movie, Splice.
The evaporator can be seen in the lab scene when Sarah Polley is doing research.
In "Avatar", a 2009 American epic science fiction film, the Heidolph rotary evaporator is used in one of their many laboratories.
The rotary evaporator can be seen in the "I Am Legend" movie, in the basement of Will Smith’s protected home lab.  
A falling film evaporator is an industrial device to concentrate solutions, especially with heat sensitive components.
The evaporator is a special type of heat exchanger.  
A rotary evaporator (or rotavap/rotovap) is a device used in chemical laboratories for the efficient and gentle removal of solvents from samples by evaporation.
When referenced in the chemistry research literature, description of the use of this technique and equipment may include the phrase "rotary evaporator", though use is often rather signaled by other language (e.g., "the sample was evaporated under reduced pressure").
Rotary evaporators are also used in molecular cooking for the preparation of distillates and extracts.
A simple rotary evaporator system was invented by Lyman C. Craig.
It was first commercialized by the Swiss company Büchi in 1957.
Other common evaporator brands are Heidolph, LabTech, Stuart, Hydrion Scientific, SENCO, IKA and EYELA.
In research the most common form is the 1L bench-top unit, whereas large scale (e.g., 20L-50L) versions are used in pilot plants in commercial chemical operations. 
An evaporator is a device used to turn the liquid form of a chemical into its gaseous form.
The liquid is evaporated, or vaporized, into a gas. 
Expansion valves are flow-restricting devices that cause a pressure drop of the working fluid.
The valve needle remains open during steady state operation.
The size of the opening or the position of the needle is related to the pressure and temperature of the evaporator.
There are three main parts of the expansion valve that regulate the position of the needle.
A sensor bulb, at the end of the evaporator, monitors the temperature change of the evaporator.
This change in temperature creates a change in pressure on the diaphragm.
For example, if the temperature in the evaporator increases, the pressure in the diaphragm increases causing the needle to lower.
Lowering the needle allows more of the working fluid into the evaporator to absorb heat.
The pressure at the inlet of the evaporator affects the position of the needle and prevents the working fluid from flowing back into the compressor.
Since the pressure before the valve is higher than the pressure after the valve, the working fluid naturally flows into the evaporator.
The pressure at the inlet of the evaporator acts on the diaphragm.
There is also a spring providing a constant pressure closing the valve needle.
The spring constantly restricts the amount of working fluid entering the evaporator.
The pressure spring can be adjusted to increase or decrease pressure based on temperature needs.
The pressure created by the spring acts on the opening of the valve.
When the pressure of the sensor bulb acting on the diaphragm is greater than the combined pressure of the evaporator and spring, the valve opens to increase the flow rate of the working fluid.
An increase of flow rate lowers the temperature of the evaporator and allows for more heat absorption.