WO2012169915A1

WO2012169915A1 - Heat exchanger tube

Info

Publication number: WO2012169915A1
Application number: PCT/PL2012/000044
Authority: WO
Inventors: Mariusz KUŹMA
Original assignee: AIC Sp zoo
Current assignee: AIC Sp zoo
Priority date: 2011-06-10
Filing date: 2012-06-06
Publication date: 2012-12-13
Anticipated expiration: 2013-12-10
Also published as: PL395219A1; EP2718653A1; PL220684B1

Abstract

The heat exchanger tube is fitted with a coaxially positioned inner element to increase the heat exchange surface area and/or agitate the agent flowing through, namely a resilient insert (2) formed out of a rectangular plate into a bushing, with three-face fins (3) shaped outwards, triangular in cross-section, with centrally pointing apexes and the opposite sides touching on the inner wall of the tube body (1), where the surface sections (4) between the fins (3) form the inner cylindrical surface of the insert. Preferably, the fins (3) have additional ribbing formed by deflecting notched sections (5) and/or embossing (6).

Description

Heat exchanger tube

The invention concerns a heat exchanger tube fitted with inserts, which increase the heat exchange surface and/or trigger turbulence of the agent flowing through.

Known from the patent specification WO 02/21056 Al is a heat exchanger tube, particularly designed for the Stirling cooler, which contains an inner cylindrical insert fitted coaxially, composed of a large number of V-shaped corrugated ring fins formed in a plate, the inner and/or outer edges of which are permanently connected to the ring.

Also known from patent specification WO 01/63197A1 is a heat exchanger tube fitted with an inner element of multi-surface side walls in the 'U' or 'V shapes, arcs or trapezium-shaped teeth, made of a flexible plate the end sides of which are mutually connected. The element is fitted coaxially inside the tube body, its outer edges contacting the inner surface of the tube body.

The purpose of this invention is to develop such a tube structure as to ensure increased heat exchange coefficient compared to the known solutions, increased strength parameters, and wear-and-tear resilience while being easy to produce.

The heat exchanger tube according to the invention, fitted with a coaxially positioned inner element to increase the heat exchange surface area and/or agitate the agent flowing through is characterised in that the element is a resilient insert formed out of a rectangular plate into a bushing, with three-face fins shaped outwards, triangular in cross-section, with centrally-pointing apexes and the opposite sides touching on the inner wall of the tube body, where the surface sections between the fins form the inner cylindrical surface of the insert.

The insert may be a single-piece unit or be composed of two, or any larger number of pieces.

The tube may be of any shape, particularly circular, oval, or polygonal. The fin walls may be flat and/or oval, their curvature of any desired radius.

Preferably, the fins have additional ribbing formed on their surfaces by deflecting notched sections of any shape and/or by embossing in any shape.

Preferably, the fin walls touching on the inner wall of the tube body are permanently connected to it.

Preferably, the minimum height of the fin in cross-section is no less than ½ of the inner radius of the tube body.

The number of fins depends on the shape and size of the tube body.

Preferably, the insert and the tube body are made of stainless steel.

In addition, a pipe or rod may be placed axially in the tube, circular, oval, or polygonal in cross-section.

The triangular shape of the fins, their entire wall connected to the inner wall of the tube body, because of the contact surface enlarged compared to other known solutions increases the heat exchange

coefficient substantially and improves the strength parameters, which allows using tubes of thinner walls. The shape further ensures even distribution of the surfaces of heat exchange over the tube circumference. The surface sections between individual fins ensure additional receipt of heat from the agent flowing in the tube. Moreover, the insert with the fins shaped in this way has a centrally formed cylindrical wall formed by the converging surfaces in between the fins, which increases stability of the tube. The resilience of the insert guarantees good contact with the inner tube wall and pertains substantially to the spontaneous formation of its internal cylindrical wall.

Exemplary embodiments of the invention are illustrated on the drawings, where:

Fig. 1 shows the tube in the axonometric projection,

Fig. 2 shows the tube with the insert drawn out,

Fig. 3 shows the tube with a two-piece insert, .

Fig. 4 shows the resilient insert in an axonometric projection,

Fig. 5 shows the tube in an orthographic projection,

Fig. 6 shows a section of a flat-surface fin,

Fig . 7 shows a section of a fin with additional ribbing in the form of deflected notches,

Fig. 8 shows a section of a fin with additional embossed ribbing,

Figs. 9a, 10a, 11a, and 12a show tubes in an orthographic projection, Figs. 9b, 10b, lib, and 12b show tubes in an orthographic projection with an extra cylindrical axially-positioned inner pipe,

Figs. 9c, 10c, 11c, and 12c show tubes in an orthographic projection with a cylindrical rod positioned axially,

Figs. 9d, lOd, lid, and 12d show tubes in an orthographic projection with an additional polygonal pipe positioned axially,

Figs. 9e, lOe, lie, and 12e show tubes in an orthographic projection with a polygonal rod positioned axially.

Exemplary embodiments of the invention;

in the body of the tube 1 the resilient insert 2 shown on Fig. 4 and Fig. 5 is placed, formed in the shape of a bushing out of a rectangular stainless steel plate, with three-face fins 3 shaped outwards, triangular in cross- section, with centrally pointing apexes and the opposite sides touching on the inner wall of the tube body 1. The surface sections 4 in between the fins 3 form the inner cylindrical surface of the insert 2. The insert 2 may be made up of a single piece, which is shown on Fig. 2, two pieces, as shown on Fig. 3, or any larger number of pieces.

In particular, the tube is circular in shape.

In one of the embodiments the walls of the fins 3 are flat, which is depicted on Figs. lOa-lOe. In other invention embodiments the walls of the fins 3 are oval with the curvatures of different radiuses, as shown on Figs. 9,11,12.

In all cases listed above, in yet another embodiment of the invention, the fin walls are added extra ribbing formed on the surface by deflecting notched sections, as shown on Fig. 7, or by embossing shown on Fig. 8. In one of the embodiments the walls of the fins 3 touching on the inner wall of the tube body 1 are not permanently connected to it, while in another the connection is permanent.

The best effects have been obtained for the height of the fin 3 no less than 1/2 of the inner radius of the tube body 1 in cross-section.

In one of the embodiments a pipe 7, cylindrical in cross-section, runs axialiy inside the tube, which is shown on Figs. 9b, 10b, lib, 12b. In another embodiment the pipe is polygonal in cross-section, as presented on Figs. 9d, lOd, lid, 12d. In yet another embodiment a rod 8, circular in cross-section, is placed axialiy in the tube, which is presented on Figs. 9c, 10c, 11c, 12c, and a further embodiment the rod 8 is polygonal in cross- section, as shown on Figs. 9e, lOe, lie, 12e.

Claims

1. Heat exchanger tube fitted with a coaxially positioned inner element to increase the heat exchange surface area and/or agitate the agent flowing through, characterised in that the element designed to increase the heat exchange surface and/or trigger turbulence is a resilient insert (2) formed out of a rectangular plate into a bushing, with three-face fins (3) shaped outwards, triangular in cross-section, with centrally-pointing apexes and the opposite sides touching on the inner wall of the tube body (1), where the surface sections (4) between the fins (3) form the cylindrical inner surface of the insert (2).

2. The tube as claimed in Claim 1, characterised in that the insert (2) is a single-piece unit or is composed of two, or any larger number of pieces.

3. The tube as claimed in Claim 1, characterised in that the body (1) is cylindrical, oval, or polygonal in cross-section.

4. The tube as claimed in Claim 1, characterised in that the fin (3) walls are flat and/or oval, their curvature of any desired radius.

5. The tubes as claimed in Claims 1 to 4, characterised in that the fins (3) have additional ribbing formed on their surfaces by deflecting notched sections (5) of any shape and/or by embossing (6) in any shape.

6. The tube as claimed in Claims 1 to 5, characterised in that the fin (3) walls touching on the inner wall of the tube body (1) are permanently connected to it.

7. The tube as claimed in Claims 1 to 6, characterised in that the minimum height of the fin (3) in cross-section is no less than ½ of the inner radius of the tube body (1).

8. The tube as claimed in Claims 1 to 7, characterised in that the number of fins (3) depends on the shape and size of the tube body (1).

9. The tube as claimed in Claims 1 to 8, characterised in that it is additionally fitted with a pipe placed axially (7), circular, oval, or polygonal in cross-section.

10. The tube as claimed in Claims 1 to 8, characterised in that it is additionally fitted with a rod placed axially (8), circular, oval, or polygonal in cross-section.

11. The tube as claimed in Claims 1 to 10, characterised in that the insert (2) is made of stainless steel.

12. The tube as claimed in Claims 1 to 11, characterised in that the body (1) is made of stainless steel.