Patent ID: 8691054

Claim:
A multi stage flash cross tube evaporator, comprising: an evaporator shell formed substantially by a shell bottom, a shell roof, a left side wall, a right side wall, a front wall and an end wall; wherein the shell bottom and shell roof are substantially of rectangular shape and arranged substantially in a horizontal position, while the left side wall, the right side wall, the front wall and the end wall are also substantially of rectangular shape and are arranged substantially in a vertical position; and wherein the multi stage flash cross tube evaporator comprising further a horizontal tier partition, substantially extending from the left side wall to the right side wall and from the front wall to the end wall and being arranged substantially in a horizontal position in between the shell bottom and shell roof, dividing the evaporator shell internally into a top tier and a bottom tier; and wherein each tier comprising a plurality of first partition walls being arranged substantially vertically and in parallel to the front wall and end wall and extending from the left side wall to the right side wall and in vertical direction in the top tier from the shell roof to the horizontal tier partition below and in the bottom tier from the shell bottom to the horizontal tier partition above, dividing each tier into a plurality of flash stages, with a first flash stage located in each tier next to the front wall, a last flash stage located in each tier next to the end wall and a plurality of intermediate flash stages in each tier located in between the first flash stage and the last flash stage; and wherein means are provided to feed a heated solution in parallel into the first flash stage of each tier; and wherein openings are cut into the first partition walls to allow the solution to pass in each tier from one flash stage to the next; and wherein means are provided to discharge the remaining concentrated solution from the last flash stage of each tier; and wherein tube bundles are installed in all flash stases to condense the vapor released from the solution, wherein each tube bundle comprises a plurality of straight tubes substantially extending across the flash stages from the left side wall to the right side wall, being fixed on each end in tube sheets; and wherein the tube bundle in at least one flash stage of each tier comprising: a first tube bundle pass and a second tube bundle pass; and wherein means are provided to feed a first part of a coolant into the tubes of the first tube bundle pass from one end of the tube bundle; and wherein further means are provided to feed a second part of the coolant into the tubes of the second tube bundle pass from the opposite end of the tube bundle, so that the second part of a coolant would be conveyed through the tubes of the second tube bundle pass in a opposite direction to the direction the first part of the coolant is conveyed through the tubes of the first tube bundle pass.