Plate of plate heat exchangers

Abstract

The present invention discloses an improve plate for plate heat exchangers (PHE) which its parameters are tailor-made to be utilized in industrial operation comprising various set of at least one first fluid and at least one second fluid having different physical and chemical characteristics and hence requires different two or more sets of PHE-related parameters. The invention also discloses a method of using and manufacturing the same.

1 . A plate of a plate heat exchanger that comprises a Heat Transfer/Transition Zone (HTZ), said HTZ comprises all plate area through which Fluid  1  is in indirect contact with Fluid  2 , said HTZ comprises Segments S(n−1), S(n), S(n+1), n being an integer number, wherein adjacent segments share a common Intermediate Line (IML),
 and wherein said HTZ comprises: 
 a at least one Standard Segment consisting of the following three members: (i) a High Wavy Zone (HWZ); (ii) one or more border lines (IML) with adjacent segments or adjacent non-heat-transfer members including gaskets, inlets and outlets; and (iii) one or more Transfer Zones or Transition Zones (TZ) interconnecting the HWZ to the IMLs; and 
 b) optionally, Nonstandard Segments denoted for segments consisting of one or two of the following: (i) a Low Wavy Zone (LWZ); (ii) a High Wavy Zone (HWZ); (iii) one or more border lines (IML) with adjacent segments or adjacent non-heat-transfer members including gaskets, inlets and outlets; and (iv) one or more Transfer Zones or Transition Zones (TZ) interconnecting the HWZ to the IMLs, 
 wherein:
 HWZ comprises high waves of alternating peak lines and valley lines in which each adjacent peak-valley-peak (P′-V′-P′) forms a flow path for a fluid flowing in an interspace above the plate and in which each adjacent valley-peak-valley (V″-P″-V″) forms a flow path for the fluid flowing in the interspace under the plate; 
 peak lines and valley lines are directed to any predefined orientation, including being substantially parallel, substantially perpendicular and in at least one portion oriented to different directions from at least one other portion; 
 peak lines can take any shape, including shapes selected from a group consisting of straight line, zigzag, curved line, polygonal shapes, at least partially curved shapes; 
 adjacent peak and valley lines are evenly spaced with a predefined peak-to-peak Wavelength (a) and/or arbitrarily spaced; 
 high waves are oriented in any predefined orientation to the North and/or to the IML; 
 HWZs are provided both as support between adjacent plates and for guiding the fluids along a segment at a predefined angle towards an IML, wherein said support along lines of abutment provide an increased ability of a stack if plates to withstand pressure and thus use of thinner metal sheet thickness; 
 HWZ length is varied from short length, providing for high pressure drop and high heat transfer coefficient, and longer length, providing for low pressure drop and lower heat transfer coefficient; 
 an area of the IML together with the two transition zones adjacent to it is denoted as an Obstacle Zone (ObZ) at least partially blocking the flow above and/or below the plate; 
 unblocked cross-section of a flow path in the IML is denoted as a Window; 
 obstacle's height plus window's height equals the drawing depth b′=b″; and 
 IMLs shape in a segmentation surface, is selected from a group consisting of a straight line at constant height, zigzag, and curved line, wherein, at least one portion of the IML is optionally oriented differently compared to a second portion of the IML, including vertical inclination, homogenously tilted inclination and heterogenous inclination. 
 
 
     
     
         2 . The plate of  claim 1 , wherein on the transition zones (TZ) interconnecting HWZ and IML, the portion connecting a peak or valley to the IML rises in an angle ranging from a steep angle substantially up to about 90 degrees, to about 5 degrees. 
     
     
         3 . The plate of  claim 1 , wherein segment S(n) is interconnectable with an adjacent segment S(n−1) and/or S(n+1), and the adjacent segment shares a mutual IML, IML(n/n+1) and IML(n/n−1) are either identical or different. 
     
     
         4 . The plate of  claim 3 , wherein for each IML(n/n+1) and IML(n/n−1), at least one first TZ is either identical or different from at least one second TZ. 
     
     
         5 . The plate of  claim 3 , wherein the HWZ of segment S(n) comprises waves which are at any angle relative to IML(n/n+1), including substantially parallel to the North, and the angle for the waves of the HWZ of adjacent segment S(n+1) is either identical or different from the angle of segment S(n). 
     
     
         6 . The plate of  claim 1 , wherein the segments either have identical or different wavelengths (a, a i ). 
     
     
         7 . The plate of  claim 1 , wherein a phase shift is provided between adjacent segments, S(n) and S(n+1), by shifting one of the adjacent segments with respect to the second segment by a phase shift offset (PH), which is positive or negative, leftward or rightward with respect to the flow direction, at an absolute value greater than or equal to 0 (i.e., no shift), lower than or equal to the wavelength a, or any other predefined value, in such a case a fluid flowing from a flow path in one HWZ towards the IML passes an obstacle and continues into the facing flow path in the second HWZ on the other side of the IML, either with or without a change in flow direction,
 wherein obstacle V′P′V′ provides two triangular windows, with a left Saddle Point (M) and a right saddle point (M) lying on IML(n/n+1) with the left window tracing the line P′(n)MP′(n+1) from left to right, and the right window tracing the line P′(n+1)MP′(n) from left to right, such that fluid flowing above the plate in flow path P′(n)V′(n)P′(n) splits into two flow paths in S(n+1), one to the left and one to the right, providing, by means of micro-channels, increased mixing as well as a left vortex and a right vortex respectively.   
     
     
         8 . The plate of  claim 7 , wherein said windows are of height b/2. 
     
     
         9 . The plate of  claim 7 , wherein phase shift offsets (PH) is 0, i.e., non phase shifted. 
     
     
         10 . The plate of  claim 7 , wherein phase shift offsets (PH) between adjacent segments are either identical or different. 
     
     
         11 . The plate of  claim 7 , wherein the phase shift offset (PH) between adjacent segments is constant and is about a/2 between segment S(n) and segment S(n+1). 
     
     
         12 . The plate of  claim 1 , wherein HWZ of segment S(n) comprises waves which are at any angle relative to IML(n/n+1), including substantially parallel to the North, and the angle for the waves of the HWZ of adjacent segment S(n+1) is either identical or different from the angle of segment S(n). 
     
     
         13 . The plate of  claim 1 , wherein flow is guided towards an obstacle line (IML) between adjacent segments, wherein flow direction of an arriving fluid meets the IML at any angle. 
     
     
         14 . The plate of  claim 13 , wherein flow paths in HWZs of two adjacent segments either guide the flow in an identical direction or in a different direction, in which case additional vorticity is provided due to the change in flow direction upon passing the IML. 
     
     
         15 . The plate of  claim 1 , having a geometry that provides an uninterrupted continuous helical flow in which the fluid does not need to accelerate from zero along the path, so pressure drop is due mainly to friction loss of the fluid and the walls, which results in an increased heat transfer coefficient and a reduced pressure drop. 
     
     
         16 . The plate of  claim 1 , wherein IML is drawn beyond the mid-plate height b/2 so as to block as much cross-section as possible for both flow paths above and below the plate, the IML thereby arcs in the segmentation surface above and below mid-plate height b/2 with points lying on flow path walls at height approximately b/2. 
     
     
         17 . The plate of  claim 1 , wherein said IML is substantially parallel to the plate XY plane at a constant height, h(Ob1)+h(Ob2)=b′=b″, and h(win1)+h(win2)=b′=b″, wherein h(Ob1) is height of an obstacle blocking flow above the plate, h(Ob2) is height of an obstacle blocking flow above the plate, h(win1) is height of a window for flow above the plate and h(win2) is height of a window for flow below the plate. 
     
     
         18 . The plate of  claim 1 , wherein the distance between HWZs of two adjacent segments is as short as about the plate thickness b, i.e., the obstacle zone width between said segments equals the sum of lengths of the TZs which it comprises,
 wherein since support between plates is not needed in such small distances, an Extra Low Wavy Zone (ELWZ) or Extra Low Wavy Area (ELWA) can be inserted in between said two TZs; said ELWZ is in a nonstandard segment S(n) now lying between standard segments S(n−1) and S(n+1);   said ELWZ is characterized by waves that take any shape, wavelength, direction and amplitude while lying between the peak plane and valley plane; ELWA waves are either evenly spaced or irregularly spaced, leaving any vertical space, also denoted as window, between said ELWZ low peaks and the peak plane, or between said ELWZ high valleys and valley plane;   waves in said ELWZ are either identical in direction and/or amplitude or different from one another in direction and/or amplitude; an x-y center plane around which said waves oscillate is either constant in height or varying in any direction; when said center of oscillation decreases or increases along said segment, a change in cross-section is provided along said segment; in areas where said center of oscillation is lower along z axis, fluid flowing above said plate has a larger cross-section and fluid flowing below said plate has a smaller cross-section;   in areas where said center of oscillation is lower along z axis, fluid flowing above said plate has a higher cross-section and fluid flowing below said plate has a larger cross-section;   ELWZ comprises protrusions rising to peak plane height b and depressions falling to valley plane height 0 taking any shape; said protrusions and depressions in said ELWZ provide extra support; when ELWZ waves have LP lines and HV lines taking a zigzag form, such points of support are found on said lines in every second change of angle; peak points in one peak line and valley points in an adjacent valley line lie on the same line when projected onto the valley plane, and approximately straight lines connecting said peak point of support and an adjacent valley point of support provide extra support for said ELWZ; and   ELWZ amplitude is either identical along the segment S(n) or changing along said segment.   
     
     
         19 . The plate of  claim 1 , wherein waves in said HWZ are asymmetric in shape with respect to an x-y plane of height b/2; cross-section area A 1  for flow paths of a fluid flowing above the plate is different in shape and/or size from cross-section area A 2  for flow paths of a fluid flowing below said plate; said cross-section areas A 1  and A 2  can be identical in shape and or/size or different for different flow paths along the segment,
 wherein when three such plates p 1 , p 2  and p 3  are stacked together, p 2  rotated by 180 degrees about z axis with respect to p 1  and p 3 , flow paths between plates p 2  and p 3  will be equal in cross-section shape to flow paths between plates p 1  and p 2  since each such flow path comprises one said A 1  shape and one said A 2  shape; when three such plates q 1 , q 2  and q 3  are stacked together where q 1  is the lowest of the three and q 3  the highest, where q 2  is rotated by 180 degrees about y axis with respect to q 1  and q 3 , and said three plates are aligned horizontally so that support is provided, each flow path for fluid flowing between plates q 1  and q 2  will comprise of two A 1  shapes and each flow path for fluid flowing between plates q 2  and q 3  will comprise of two A 2  shapes. 
 
     
     
         20 . The plate of  claim 1 , wherein distance waves in said HWZ are asymmetric in shape with respect to an x-y plane of height b/2; cross-section area for a first flow path of a fluid flowing above the plate (P′V′P′) is different in shape and/or size from the cross-section area of a second flow path of a fluid flowing below said plate (V″P″V″) sharing a common wall with said first flow path; said cross-section areas can be identical in shape and or/size or different for different flow paths along the segment;
 wherein when three such plates q 1 , q 2  and q 3  are stacked together where q 1  is the lowest of the three and q 3  the highest, where q 2  is rotated by 180 degrees about y axis with respect to q 1  and q 3 , and said three plates are aligned horizontally so that support is provided, a first flow path for fluid flowing above plate q 1  meets a second flow path of q 2  where said first and said second flow path cross-sections are mirror images of each other and a third flow path for fluid flowing below plate q 3  meets a fourth flow path of q 2  where said third and said forth flow path cross-sections are mirror images of each other. 
 
     
     
         21 . The plate of  claim 20 , wherein adjacent segments are phase-shifted by an offset of absolute value greater than or equal to 0 (no shift), lower than or equal to the wavelength a, or any other predefined value; when said offset between segments S(n) and S(n+1) is equal to about a/2, and the channel q 1  and q 2  has larger cross section than the channel between plates q 2  and q 3 , flow along a flow path of segment S(n) with larger cross section between plates q 1  and q 2  is partly blocked by the shifted smaller cross-section shape in the next segment S(n+1), providing a left window and a right window characterized by a large window height and a high obstacle in both the upper plate q 2  and lower plate q 1 ; flow along a flow path of segment S(n+1) with smaller cross section between q 2  and q 3  is partly blocked by the shifted smaller cross-section shape in segment S(n), providing a left window and a right window characterized by a small window height and a high obstacle in both the upper plate q 3  and lower plate q 2 ; by inserting a nonstandard segment with straight-line IMLs parallel to x-y plane on both sides between two said segments where each IML is of a different height, for the channel with larger cross section between plates q 1  and q 2  results in increased heat transfer for the larger cross-section channel. 
     
     
         22 . A plate heat exchanger comprising three or more symmetric plates according to  claim 1 , wherein a symmetric plate is defined by having flow paths and/or windows, with a shape, size, direction and cross-section area (A 1 ) above the plate, being the same from flow paths and/or windows, with a shape, size, direction and cross-section area (A 1 ) below the plate, wherein:
 when three symmetric plates are stacked together for use in a heat exchanger, with a middle plate shape rotated 180 degrees about the Z axes of the plate plane relatively to the plates above and below, forms a flow channel between a below first symmetric plate and the middle symmetric plate provides an equal shape, size and cross-section area (A 1 +A 1 ), as a flow channel between the middle symmetric plate and the third plate (A 1 +A 1 ), and creating an equal geometrical form to the channels of Fluid  1  and of Fluid  2 .   
     
     
         23 . A plate heat exchanger comprising three or more asymmetric plates according to  claim 1 , wherein an asymmetric plate is defined by having flow paths and/or windows, with a shape, size, direction and cross-section area (A 1 ) above the plate, being different from flow paths and/or windows, with a shape, size, direction and cross-section area (A 2 ) below the plate, wherein:
 when three asymmetric plates are stacked together for use in a heat exchanger, with a middle plate shape rotated 180 degrees about the Y axes of the plate plane, forms a mirror shape plate (relatively to the plates above and below), a flow channel between a below first asymmetric plate and the middle asymmetric plate provides a different shape, size and cross-section area (A 1 +A 1 ), than a flow channel between the middle asymmetric plate and the third plate (A 2 +A 2 ), and creating an unequal geometrical form to the channels of Fluid  1  and Fluid  2 .