Question: When was the first evaporator patented?
About the article "Maple syrup", section "Modern era".

Candidate passages:
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. 
  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.  
Around the time of the American Civil War, syrup makers started using large, flat sheet metal pans as they were more efficient for boiling than heavy, rounded iron kettles, because of a greater surface area for evaporation.
Around this time, cane sugar replaced maple sugar as the dominant sweetener in the US; as a result, producers focused marketing efforts on maple syrup.
The first evaporator, used to heat and concentrate sap, was patented in 1858.
In 1872, an evaporator was developed that featured two pans and a metal arch or firebox, which greatly decreased boiling time.
Around 1900, producers bent the tin that formed the bottom of a pan into a series of flues, which increased the heated surface area of the pan and again decreased boiling time.
Some producers also added a finishing pan, a separate batch evaporator, as a final stage in the evaporation process.
Buckets began to be replaced with plastic bags, which allowed people to see at a distance how much sap had been collected.
Syrup producers also began using tractors to haul vats of sap from the trees being tapped (the sugarbush) to the evaporator.
Some producers adopted motor-powered tappers and metal tubing systems to convey sap from the tree to a central collection container, but these techniques were not widely used.
Heating methods also diversified: modern producers use wood, oil, natural gas, propane, or steam to evaporate sap.
Modern filtration methods were perfected to prevent contamination of the syrup.
A large number of technological changes took place during the 1970s.
Plastic tubing systems that had been experimental since the early part of the century were perfected, and the sap came directly from the tree to the evaporator house.
Vacuum pumps were added to the tubing systems, and preheaters were developed to recycle heat lost in the steam.
Producers developed reverse-osmosis machines to take a portion of water out of the sap before it was boiled, increasing processing efficiency.
Improvements in tubing and vacuum pumps, new filtering techniques, "supercharged" preheaters, and better storage containers have since been developed.
Research continues on pest control and improved woodlot management.
In 2009, researchers at the University of Vermont unveiled a new type of tap that prevents backflow of sap into the tree, reducing bacterial contamination and preventing the tree from attempting to heal the bore hole.
Experiments show that it may be possible to use saplings in a plantation instead of mature trees dramatically boosting productivity per acre.
Augmented by the thermal environment of the spacecraft, the water evaporator and 8 Watt electric heater will maintain water temperature at 60±5 °F (15.5±3 °C).
The water supply for the evaporator is contained in a rubber bladder supported by a ring in the canister immediately above the lower dome.
When water temperature exceeds the nominal 60 °F, a ground command actuates a timing circuit operating a valve.
As a result of the ambient pressure inside the canister, water is forced from the bladder through the valve and into the evaporator.
Internal heat loads are transferred through a heat exchanger to the evaporator and are dissipated in evaporating the water. 
This type of evaporator is generally made of long tubes ( in length) which are surrounded by steam jackets.
The uniform distribution of the solution is important when using this type of evaporator.
The solution enters and gains velocity as it flows downward.
This gain in velocity is attributed to the vapor being evolved against the heating medium, which flows downward as well.
This evaporator is usually applied to highly viscous solutions, so it is frequently used in the chemical, food, and fermentation industries.