DK143472B - ROWS FOR USE IN A HEAT EXCHANGE - Google Patents

Description

(19) DENMARK

| J | red PUBLICATION WRITING (11) 143472 B

DIRECTORATE OF PATENT AND TRADEMARKET

(21) Application No. 2813/73 (51) presently C.3 F 28 F 1/42 (22) Submission date 22 · May 1973 // B 21 C 37/20 (24) Running day 22 May 1973 (41) Aim. available Nov. 24; 1973 (44) Posted Aug 24 1981 (86) International application no. - (86) International filing day - (85) Continuation day - (62) Master application no. **

(30) Priority 23 · May 1972, 6671/72, SE

(71) Applicant AGA HEATING AB, 412 85 Goeteborg, SE.

(72) Inventor Helge Jonae son, SE.

(74) Clerk of the International Patent Office.

(54) Pipe for use 1 a heat exchanger.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a tube intended for use in a heat exchanger, such as a conventional heat exchanger type heat exchanger, which serves to pass through one fluid, which tube has helical indentations in the tube wall so as to form a helical channel on the outside of the tube. the inside of the tube a corresponding helical bead.

The object of the present invention is to provide a tube of simple and stable structure which enables an increase in the efficiency of the heat transfer from one fluid to the other, so as to provide a specific heat transfer effect r can perform the heat exchanger with smaller dimensions than has hitherto been possible.

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To achieve this, the tube according to the invention is peculiar in that its exterior has three or more gutter-shaped impressions extending helically round, and a corresponding number of gutter-like impressions extending helical left, the impressions extending helical-right with the same increase as the indentations extending helically to the left, and the increment of the indents substantially exceeding the diameter of the tube, so as to form on the outside of the tube a checkered or square pattern of impressions, which on the inside of the tube is matched by a checkered or square pattern of one another intersecting beads.

With this arrangement, a pipe is obtained by simple means to meet the requirements, the design according to the invention giving the pipe a greater strength against external pressure and by bending retaining its cross-section, and that, through the passage of fluid through the pipe, an increased turbulent flow along the pipe wall and thus an increase in the heat transfer number, which means that for the same effect one can produce the heat exchanger with a smaller transition surface.

The invention will be explained in more detail below with reference to the drawing, in which fig. 1 is a perspective view; FIG. 2 is a side view and FIG. 3 is a cross-section of a pipe according to the invention with a checkered or square pattern; FIG. 4 is an axial section and FIG. 5 is a top view of a pipe package consisting of three coils wound close to each other in the right-hand direction; FIG. 6 is an axial section and FIG. 7 is a top plan view of a tube package consisting of three telescopically interposed or closely wound tubes which are wound alternately right round and left round, and FIG. 8 and 9 illustrate the basic structure of a tool for making helical extending impressions in a pipe drawn through the tool.

The tube of FIG. 1-3 are formed with four gutter-shaped indentations 10, which are successively spaced apart and extending helically round, and four gutter-shaped impressions 11 having the same distance and extending helical-left. The intersecting impressions 10 and 11 together form a checkered or square pattern.

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The pitch of the impressions substantially exceeds the diameter of the tube, so that the substantially rhombic fields of the checkered pattern are given substantially the same axial and peripheral extent. The checkered or square pattern of intersecting impressions 10 and 11 on the outside of the tube is matched by a checkered or square pattern of beads on the inside of the tube. These beads, when passing a fluid through the tube, cause the fluid to be forced into an increased turbulent flow at the tube wall, thereby increasing the heat transfer rate so that for the same effect the heat exchanger with a smaller heat transfer surface can be performed.

FIG. 4 and 5 show a pipe package consisting of three pipe coils 12, 13 and 14, which are wound close together in such a way as to provide a cross-section of a triangle of the tubes. The pipe package is tightly enclosed by an inner wall cylinder 15 and an outer wall cylinder 16. It is assumed that the pipe spirals are connected in parallel for flow through the tubes from top to bottom, and that the rewinding fluid flows from below upwards through the annular space enclosed between the cylinder walls. , and for the most part filled out by the pipe package. The intersecting impressions in the tubes define bedding channels of sufficient flow area for the rewinding fluid.

At the heat exchanger of FIG. 6 and 7, the tube package consists of three telescopically interposed or retracted tube coils 17, 18 and 19, which are alternately wound right round and left round. Here, too, the indentations in the exterior of the tubes define sufficient flow channels for the fluid which rewinds the tubes.

The FIG. 8 and 9 are advantageous for generating indentations in the tube wall which form a four-screw. In a retainer 20, four radially directed bolts 21, which are at their inner end, are arranged at their inner end with a fork 22 in which a roller 23 is mounted rotatably. The bolts 21 are fixed by nuts 24 and 25 in such positions that the plane through the periphery of the respective rollers forms an acute angle with the common plane through the axes of the four bolts. The tool is mounted for rotation about the axis of the ring 20. By pulling a tube through the tool along the axis, the four rollers 23 press four smoothly extending helical impressions into the tube wall, which impressions on the inside of the tube are matched by four helical beads. One