Triple Effect Evaporators

Pan Room #1 and #2 Evaporator Units

I am going to tell you a story that nobody cares about and makes no difference anyway.

In 1961 and 1962 I worked in  #1 and #2 pan rooms. This little story is about the Three Stage Evaporator Units that were in #1 and #2 pan rooms. Originally they were in South America used for making sugar. They were cast iron pieces bolted together to make a ball sitting on a cone like an ice cream cone.

They were disassembled in South America, put on ship and brought to Trona where they were reassembled and made potash, borax and soda ash for the rest of their lives. The only problem was cast iron has to be heated or cooled evenly or it will crack. They had to wash these things out every two weeks and try as they might to avoid it eventually they would have a crack.

There might be a way to weld cast iron now, but in 1920 thru 1960 you would have to find someone to sew cast iron up. In 1960 they were down to one guy in the U.S. and maybe the world who knew how to do it and he was getting old. The cast iron was about 1 ½ “ thick. The old guy would drill a hole on each side of the crack and drive a thing that looked a big staple into holes. He would follow the crack putting a staple every inch or so until the crack ran out.

This man was about 80 years old and they had to send another man in with the old guy to make sure that he didn’t pass out or die. They had already built unit #3 out of steel to solve the cracking problem. They knew that if they didn’t replace the cast iron evaporators soon that they wouldn’t be able to repair them so they started building unit #4 which was big enough to replace both #1 and #2 units. By 1963 unit #4 was operational and the cracking problem was solved.

The picture at the beginning of this post is the triple effect evaporator in Pan Room #1.

Alfred De Ropp Jr., the son for the president of the American Trona Company, was a research Engineer in Trona in 1918. At that time he wrote and article about the evaporators and how they operated. It was published in 1918 in Chemical & Metallurgical Engineering, Volume 19 edited by Eugene Franz Roeber and Howard Coon Parmelee. The Journal is available from Google Book by clicking on the link above.

The tenth edition of the American Fertilizer Handbook published in 1917 mentions the evaporator house (Pan Room) in a short article that was written before the evaporator houses were operational. It says:

“The evaporator house at Trona is a steel structure 109 feet high, and the boilers will have 2,000 horsepower. The spray pond for cooling condenser water is built with reinforced concrete. A reinforced concrete chimney, 150 feet high and 9 feet in diameter in the clear on top, tanks a crystallizing vats, triple effect evaporators and a traveling crane for the evaporating building are features of the equipment.”

Click here to see a Diagram of the Evaporators in Pan House 1 and 2.


Location of Pan Rooms (Photo from SVHS)

Location of Pan Rooms


#1 & #2 Evaporator House (Pan Room)

#1 & #2 Evaporator House (Pan Room)
#3 Pan Room Evaporator

Pan Room #3 Evaporator

One thought on “Pan Room #1 and #2 Evaporator Units

  1. David L. Stevens

    Correct me if I am wrong but it sounds like the evaporators were they key to the whole plant operation. It was the first step that began the chemical extraction process once the lake brine entered the plant.


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