Evaporator

Abstract

The present invention comprises an apparatus and method for evaporating a liquid to produce a product liquid and a vapor. Liquid is evaporated under the influence of a heat transfer medium in a heat exchanger comprised of a bank of tube plates formed from corrugated sheets. Vapor produced is separated from product liquid by a vapor collector which causes vapor to flow upward and into the collector from a downward-flowing product liquid and vapor stream. Backsplash entrainment into the vapor collector is prevented by an anti-backsplash device disposed between the vapor collector and a reservoir into which product liquid flows.

1 . An evaporator for evaporating a liquid, comprising:
 a. a housing;   b. a heat exchanger for transferring heat from a heat transfer medium to the liquid and producing a vapor and a product liquid;   c. a vapor collector disposed substantially within the housing and including a vapor inlet having a downward-facing portion; and   d. wherein the vapor produced by the heat exchanger flows downwardly past an upper portion of the vapor collector and upwardly into the vapor inlet.   
     
     
         2 . The evaporator of  claim 1  wherein the heat exchanger includes a liquid inlet, an outlet for product liquid and vapor, and a bank of tube plates with each tube plate including a pair of corrugated sheets secured together wherein each corrugated sheet includes a series of alternating concave and convex segments with adjacent segments being generally mirror images of each other, and wherein the corrugated sheets comprising each tube plate are disposed such that each concave segment of one sheet faces a concave segment of the other sheet, and wherein each convex segment of one sheet contacts or lies closely adjacent a convex segment of the other sheet and wherein the tube plates are spaced apart and spacing the tube plates includes bracing the tube plates with two or more plates with each plate having openings shaped to generally conform to the tube plates and thereby adapted to retain the shape of each tube plate when exposed to pressure. 
     
     
         3 . The evaporator of  claim 1  comprising a reservoir disposed below the vapor collector to receive the product liquid, and an anti-splash device disposed between the vapor collector and the reservoir for preventing backsplash of product liquid from a surface of the product liquid in the reservoir into the vapor collector. 
     
     
         4 . The evaporator of  claim 3  wherein the heat exchanger includes a liquid inlet, an outlet for product liquid and vapor, and a bank of tube plates with each tube plate including a pair of corrugated sheets secured together wherein each corrugated sheet includes a series of alternating concave and convex segments with adjacent segments being generally mirror images of each other, and wherein the corrugated sheets comprising each tube plate are disposed such that each concave segment of one sheet faces a concave segment of the other sheet, and wherein each convex segment of one sheet contacts or lies closely adjacent a convex segment of the other sheet 
     
     
         5 . The evaporator of  claim 1  wherein the heat exchanger comprises a plurality of tube plates with each tube plate being adapted to receive the liquid; and, wherein the tube plates are spaced apart to form a series of passageways for permitting the heat transfer medium to flow there between. 
     
     
         6 . The evaporator of  claim 5  wherein each tube plate includes a pair of corrugated sheets secured together so as to form a series of elongated tubes oriented vertically therein. 
     
     
         7 . The evaporator of  claim 1  wherein the vapor collector includes a duct that extends transversely below the heat exchanger. 
     
     
         8 . The evaporator of  claim 1  wherein a source of reduced pressure is operatively connected to the vapor collector for maintaining a fluid pressure within the vapor collector less than a fluid pressure within the heat exchanger. 
     
     
         9 . The evaporator of  claim 1  wherein the evaporator includes a series of modules with each module including at least a heat exchanger. 
     
     
         10 . The evaporator of  claim 9  wherein the modules are stacked one above another in a generally vertical arrangement. 
     
     
         11 . An evaporator for evaporating a liquid, comprising:
 a. a housing;   b. a heat exchanger for evaporating a portion of the liquid and generating a product liquid and a vapor;   c. a vapor outlet disposed below at least a portion of the heat exchanger for permitting vapor to exit the housing;   d. a reservoir disposed below the vapor outlet to receive the product liquid; and,   e. an anti-splash device disposed between the vapor outlet and the reservoir for preventing backsplash of product liquid from a surface of the product liquid in the reservoir into the vapor outlet.   
     
     
         12 . The evaporator of  claim 11  wherein the heat exchanger includes a liquid inlet, an outlet for the product liquid and vapor, and a bank of tube plates with each tube plate including a pair of corrugated sheets secured together wherein each corrugated sheet includes a series of alternating concave and convex segments with adjacent segments being generally mirror images of each other, and wherein the corrugated sheets comprising each tube plate are disposed such that each concave segment of one sheet faces a concave segment of the other sheet, and wherein each convex segment of one sheet contacts or lies closely adjacent a convex segment of the other sheet. 
     
     
         13 . The evaporator of  claim 11  including a vapor collector disposed generally between the heat exchanger and the reservoir and including a vapor inlet having a downward-facing portion. 
     
     
         14 . The evaporator of  claim 11  including a vapor collector extending transversely within the housing and between the heat exchanger and the reservoir and wherein the vapor collector includes a vapor inlet including a downward facing portion. 
     
     
         15 . The evaporator of  claim 11  wherein the anti-splash device comprises a series of spaced-apart plates. 
     
     
         16 . The evaporator of  claim 15  wherein the plates are disposed in a parallel relationship and slightly angled with respect to the general direction of product liquid flow. 
     
     
         17 . The evaporator of  claim 11  wherein the anti-splash device comprises a mesh structure. 
     
     
         18 . The evaporator of  claim 11  wherein the vapor outlet forms a part of a vapor collector disposed substantially within the housing and above the anti-splash device. 
     
     
         19 . The evaporator of  claim 18  wherein the vapor collector includes a vapor inlet having a downward-facing portion and communicating fluidly with the vapor outlet. 
     
     
         20 . An evaporator for evaporating a liquid, comprising:
 a. a housing;   b. a heat exchanger to evaporate a portion of a liquid to produce a product liquid and a vapor;   c. a vapor outlet disposed below a substantial portion of the heat exchanger;   d. wherein the heat exchanger includes:
 i) a liquid inlet; 
 ii) an outlet for product liquid and vapor; 
 iii) a bank of spaced-apart tube plates with each tube plate including a pair of corrugated sheets secured together; 
 iv) each corrugated sheet including a series of alternating concave and convex segments with adjacent segments being generally mirror images of each other; 
 v) wherein the corrugated sheets are disposed such that each concave segment of one sheet faces a concave segment of the other sheet, wherein each convex segment of one sheet contacts or lies closely adjacent a convex segment of the other sheet; and 
   vi) wherein the heat exchanger includes one or more vertically spaced-apart horizontal plates, each plate having one or more openings for receiving the tube plates.   
     
     
         21 . The evaporator of  claim 20  including a vapor collector disposed substantially within the housing and including a vapor inlet having a downward-facing portion. 
     
     
         22 . The evaporator of  claim 20  comprising a reservoir disposed below the vapor outlet to receive the product liquid and an anti-splash device disposed between the vapor outlet and the reservoir for preventing backsplash of product liquid from a surface of the product liquid in the reservoir into the vapor outlet. 
     
     
         23 . The evaporator of  claim 20  including a vapor collector including a vapor inlet having a downward-facing portion and the vapor collector disposed substantially within the housing, a reservoir disposed below the vapor collector to receive the product liquid, and an anti-splash device disposed between the vapor collector and the reservoir for preventing backsplash of product liquid from a surface of the product liquid in the reservoir into the vapor collector. 
     
     
         24 . The evaporator of  claim 20  wherein the inlet is disposed at a top portion of the heat exchanger and the outlet is disposed at a bottom portion of the heat exchanger; and, wherein the elongated tubes extend between the top and bottom portions. 
     
     
         25 . The evaporator of  claim 20  including at least a pair of spaced apart plates with each plate having a series of openings therein for receiving the tube plates, and wherein the openings within the plates maintain the tube plates in spaced apart relationship so as to define passageways between the tube plates for permitting the heat transfer medium to flow. 
     
     
         26 . The evaporator  claim 20  wherein one or more plates interconnect the tube plates and form a unitary structure. 
     
     
         27 . The evaporator of  claim 20  including a pair of vertically spaced-apart horizontal plates with each plate including one or more openings shaped to generally conform to the tube plates and thereby adapted to retain the shape of the tube plates when exposed to pressure. 
     
     
         28 . The evaporator of  claim 20  wherein a first plate is disposed at a top portion of the heat exchanger and is secured to the tube plates and to a wall of the housing; and, wherein a second plate is disposed at a bottom portion of the heat exchanger and is secured to the tube plates and to the wall of the housing, thereby forming a closed space between the first and second plates and within the housing. 
     
     
         29 . The evaporator of  claim 20  wherein the housing includes a heat transfer medium inlet and a heat transfer medium outlet for accommodating the flow of the heat transfer medium within the heat exchanger. 
     
     
         30 . The evaporator of  claim 20  wherein the vapor outlet forms a part of a vapor collector disposed substantially within the housing. 
     
     
         31 . The evaporator of  claim 30  wherein the vapor collector is communicatively connected to the vapor outlet and includes a vapor inlet having a downward-facing portion. 
     
     
         32 . The evaporator of  claim 30  including a reservoir disposed below the vapor collector for receiving the product liquid. 
     
     
         33 . The evaporator of  claim 32  including an anti-splash device disposed between the vapor collector and the reservoir for preventing product liquid from splashing from the reservoir into the vapor outlet. 
     
     
         34 . A method of evaporating a liquid comprising:
 a. flowing the liquid through an evaporator comprising a housing, a heat exchanger, and a vapor collector;   b. heating the liquid by flowing a heat transfer medium through the heat exchanger and producing a product liquid and a vapor; and   c. directing the product liquid and vapor downwardly past an upper portion of the vapor collector and inducing the vapor upwardly into the vapor collector.   
     
     
         35 . The method of  claim 34  wherein inducing the vapor upwardly into the vapor collector includes providing a reduced pressure source to reduce the pressure in the vapor collector and draw the vapor through a downward-facing vapor inlet disposed in the vapor collector. 
     
     
         36 . A method of evaporating a liquid comprising:
 a. flowing the liquid into a heat exchanger;   b. heating the fluid by flowing a heat transfer medium through the heat exchanger and producing a product liquid and a vapor with the product liquid falling into an underlying reservoir;   c. inducing the vapor through a vapor outlet associated with the evaporator; and   d. preventing product liquid backsplash droplets from being entrained with the vapor and entering the vapor outlet.   
     
     
         37 . The method of  claim 36  wherein preventing backsplash droplets from entering the vapor outlet includes deflecting the droplets by an anti-splash device and causing the droplets to settle back into reservoir. 
     
     
         38 . A method of fabricating an evaporator comprising:
 a. constructing a heat exchanger having a bank of spaced-apart tube plates with each tube plate including two corrugated sheets with each sheet having alternating concave and convex segments,   b. securing the two corrugated sheets of each tube plate together by aligning the concave and convex segments and affixing and sealing opposite edges of the two corrugated sheets together such that the convex segments abut or lie in close proximity to each other and the concave segments form tubes for generally containing a product liquid and a vapor;   c. spacing adjacent formed tube plates so as to define passageways there between for permitting a heat transfer medium to move between the tube plates; and,   d. wherein spacing adjacent formed tube plates includes bracing the tube plates with two or more plates with each plate having openings shaped to generally conform to the tube plates and thereby retain the shape of each tube plate when exposed to pressure   
     
     
         39 . The method of  claim 38  including disposing a vapor collector, in the form of a duct transversely below the heat exchanger wherein the duct includes a closed end, open end, and a downward-facing vapor inlet. 
     
     
         40 . The method of  claim 38  including positioning an anti-splashback device below a vapor collector for preventing backsplash droplets of the liquid product from entering the vapor collector which is disposed between the heat exchanger and a reservoir.