AU2011361284A1 - Steam drier - Google Patents

Description

STEAM DRIER

FIELD OF THE INVENTION

The invention relates to the steam drier defined in the preamble of claim 1.

BACKGROUND OF THE INVENTION

Known from publication US 6, 415, 527 is a steam drier commonly used especially for continuous drying of ore concentrate, i.e. to remove water, before feeding the concentrate into a smelting furnace. The steam drier includes a rotatable elongated cylindrical drum. Pro^¬ vided in the interior space within the drum is a set of heating elements supported on the drum to rotate along with it. Each heating element is formed as a self-supporting structure, being detachable and re^¬ placeable as one assembly. Each heating element has its own steam circulation separate from the steam circulation of the other heating elements. The formation of a steam line from separate heating elements, each with its own steam circulation, is advantageous because, if a leak appears within the element, the feed of steam to the defective element can be disconnected and, at the same time, the steam drying can be continued without in- terruption at a bit lower drying capacity. When one wishes to change the heating element, it can be detached as an individual assembly and quickly replaced with a functioning element. Each heating element includes a pair of straight first longitudinal pipes supported in parallel to each other at a distance from each other. The first longitudinal pipes extend in the longitudinal direction of the drum. Furthermore, the heating element includes a pair of curved end pipes extending substantially trans- versely relative to the first longitudinal pipes in the vicinity of the ends of the first longitudinal pipes. The end pipes connect the first longitudinal pipes rigidly to each other so that the first longitu- dinal pipes are provided in flow connection to each other through the end pipes in order to allow the flow of steam within the heating element.

In addition to the end pipes that extend between the ends of the heating element, the known heating element includes transversal curved intermediate pipes provid^¬ ed along the length of the heating element at a dis^¬ tance from each other to extend between the first longitudinal pipes. The curvature of the intermediate pipes corresponds to the curvature of the end pipes. The intermediate pipes and the first longitudinal pipes are fastened to each other so that a flow con^¬ nection is provided between them in order to allow the flow of steam. The intermediate pipes are transverse because, from the wear resistance standpoint, the in^¬ tention has been that they should be parallel to the movement of the material to be dried and the material would not resist rotation of the element. A problem in the known structure of the heating ele^¬ ment is the very large number of weld connection lines, which makes the manufacturing costs higher. The large number of curved intermediate pipes also causes additional costs because each intermediate pipe must be bent to a suitable curvature. A number of apertures that corresponds to the large number of intermediate pipes must correspondingly be provided on the longitu^¬ dinal pipes in order to enable the flow connection. OBJECTIVE OF THE INVENTION An objective of the invention is to eliminate the drawbacks referred to above.

Especially, an objective of the invention is to dis- close a steam drier wherein the manufacturing costs of the heating elements are substantially lower than be^¬ fore .

SUMMARY OF THE INVENTION

The steam drier according to the invention is characterized by what has been presented in claim 1.

The steam drier according to the invention includes a rotatable elongated drum and a set of heating elements provided in the interior space within the drum and supported on the drum in order to rotate along with the drum. Each heating element includes a pair of straight first longitudinal pipes supported in paral^¬ lel to each other at a distance from each other. The first longitudinal pipes extend in the longitudinal direction of the drum. Furthermore, the heating ele^¬ ment includes a pair of end pipes extending substan^¬ tially transversely relative to the first longitudinal pipes in the vicinity of the ends of the first longi- tudinal pipes. The end pipes connect the first longi^¬ tudinal pipes rigidly to each other. The first longi^¬ tudinal pipes are provided in flow connection to each other through the end pipes in order to allow the flow of steam within the heating element.

According to the invention the heating element includes a set of straight second longitudinal pipes provided in parallel to the first longitudinal pipes, the second longitudinal pipes being fastened to the end pipes by each end so that each two adjacent second longitudinal pipes are disposed at a distance from each other and the second longitudinal pipes are pro^¬ vided in flow connection with the end pipes.

An advantage of the invention is that, compared with the conventional known heating element, the number of weld connections in the heating element according to the invention is substantially smaller. Holes do not have to be made on the first longitudinal pipes except in the area of the end pipes. The second longitudinal pipes are straight so they need not be bent. The manu^¬ facture includes fewer work stages than before and the manufacturing costs are cheap.

In one embodiment of the steam drier the heating element includes a set of curved stiffening members arranged to extend transversely relative to the first and the second longitudinal pipes and fastened at a distance from each other along the length of the heating element. In one embodiment of the steam drier a set of heating elements is provided on a support structure adapted to bind said heating elements to each other to form a self- supporting package. In one embodiment of the steam drier the heating element includes intermediate pipes in parallel to the end pipes extending substantially transversely relative to the first longitudinal pipes. The intermediate pipes are fastened by the ends to the first longitudinal pipes so that the first longitudinal pipes are provided in flow connection to each other through the intermediate pipes .

In one embodiment of the steam drier the end pipes are curved. In one embodiment of the steam drier the end pipes are straight .

In one embodiment of the steam drier the end pipes are V-shaped.

LIST OF FIGURES

In the following the invention will be described in detail with an example embodiment, referring to the accompanying drawing in which

Fig. 1 schematically presents partial cross section of one embodiment of the steam drier according to the in^¬ vention,

Fig. 2 presents section II-II,

Fig. 3 presents a heating element of a first embodi^¬ ment of the invention, and

Fig. 4 presents section IV-IV from Fig. 3,

Fig. 5a presents cross section of an embodiment corre^¬ sponding to Fig. 4 where the end pipes of the heating element are straight,

Fig. 5b presents cross section of an embodiment corre^¬ sponding to Fig. 4 where the end pipes of the heating element are V-shaped.

Fig. 6 presents an embodiment where heating elements of different sizes are assembled together to form a self-supporting package, and Fig. 7 presents a heating element of a second embodi^¬ ment of the invention. DETAILED DESCRIPTION OF THE INVENTION

Fig. 1 schematically presents a steam drier.

The steam drier includes an elongated cylidrical drum 1. Fastened to the circumference of the drum 1 are two bearer rings 10. The drum 1 lies on rolls 11 supported on the bearer rings 10. The drum 1 is rotat^¬ ed by rotating means 12.

As shown in Fig. 2, provided within the drum 1 is a set of heating elements 2. The heating elements 2 are supported on the drum 1 by braces 13 fastened to the drum 1, so that the heating elements 2 rotate along with the drum 1. The radius of curvature of the curved heating elements 2 increases in moving from the center of the drum 1 toward the circumference.

Fig. 3 and 4 show one of the heating elements 2. The heating element 2 includes a pair of straight first longitudinal pipes 3 and 4 supported in parallel to each other at a distance A from each other. The first longitudinal pipes 3 and 4 extend in the longitudinal direction of the drum 1.

Furthermore, the heating element 2 includes a pair of curved end pipes 5, 6 extending substantially trans^¬ versely relative to the first longitudinal pipes 3, 4 in the vicinity of the ends of the first longitudinal pipes. The curved end pipes 5, 6 connect the first longitudinal pipes 3 and 4 rigidly to each other. The radius of curvature of the end pipes 5, 6 determines the curvature of the element. The first longitudinal pipes 3 and 4 are provided in flow connection to each other through the end pipes 5 and 6 so that the steam and condensate are able to flow within the heating el^¬ ement 2.

The heating element 2 includes a set of straight se- cond longitudinal pipes 7 provided adjacently in par^¬ allel to the first longitudinal pipes 3, 4. The second longitudinal pipes 7 are fastened by each end to the end pipes 5, 6 so that each two adjacent second longi^¬ tudinal pipes are disposed at a distance B from each other and the second longitudinal pipes 7 are provided in flow connection with the end pipes 5, 6. In addition, the heating element 2 includes a set of curved stiffening members 8 arranged to extend transversely relative to the first and the second longitudinal pipes and fastened at a distance L from each other along the length of the heating element.

Fig. 5a presents an embodiment corresponding to Fig. 4 where the end pipes 5 and 6 (not shown) are straight. Fig. 5b presents an embodiment corresponding to Fig. 4 where the end pipes 5 and 6 (not shown) are V-shaped.

Fig. 6 further presents one embodiment where a plural^¬ ity of heating elements 2 of different sizes according to Fig. 4 are provided on a support structure 9 bind^¬ ing the heating elements 2 to each other to form a self-supporting package 10. The self-supporting package 10 may contain two or more heating elements 2. A similar package 10 can also be formed from the heating elements according to Fig. 5a or Fig. 5b.

Fig. 7 presents yet one embodiment of the heating ele^¬ ment 2 that may be as shown in Fig. 3 and 4 or 3 and 5a or 5b. A difference to the embodiment described above is that in the embodiment of Fig. 7 the heating element 2 may include, in parallel to the end pipes 5 and 6, intermediate pipes 14 extending substantially transversely relative to the first longitudinal pipes 3, 4. The end pipes 5, 6, the stiffening members 8 and the optional intermediate pipes 14 connect the first longitudinal pipes 3 and 4 rigidly to each other. The first longitudinal pipes 3 and 4 are provided in flow connection to each other through the end pipes 5 and 6 and the intermediate pipes 14 so that the steam and condensate are able to flow within the heating element 2.

The invention is not limited merely to the examples of its embodiments referred to above; instead, many vari^¬ ations are possible within the scope of the inventive idea defined by the claims.

Claims (7)

1. A steam drier including a rotatable elongated drum (1) and a set of heating elements (2) provided in the interior space within the drum and supported on the drum in order to rotate along with the drum, each heating element including

- a pair of straight first longitudinal pipes (3, 4) supported in parallel to each other at a dis- tance (A) from each other, the first longitudinal pipes extending in the longitudinal direction of the drum, and

- a pair of end pipes (5, 6) extending sub^¬ stantially transversely relative to the first longitu- dinal pipes in the vicinity of the ends of the first longitudinal pipes, wherein the end pipes connect the first longitudinal pipes rigidly to each other so that the first longitudinal pipes are provided in flow con^¬ nection to each other through the end pipes in order to allow the flow of steam within the heating element, c h a r a c t e r i z e d in that the heating element (2) includes a set of straight second longitudinal pipes (7) provided in parallel to the first longitudinal pipes (3, 4), the second longitudinal pipes being fas- tened by each end to the end pipes (5, 6) so that each two adjacent second longitudinal pipes are disposed at a distance (B) from each other and the second longitu^¬ dinal pipes (7) are provided in flow connection with the end pipes (5, 6) .

2. The steam drier according to claim 1, c h a r a c t e r i z e d in that the heating element (2) includes a set of stiffening members (8) arranged to extend transversely relative to the first and the second lon- gitudinal pipes and fastened at a distance (L) from each other along the length of the heating element.

3. The steam drier according to claim 1 or 2, c h a r a c t e r i z e d in that a set of two or more heating elements (2) is provided on a support structure (9) adapted to bind said heating elements (2) to each oth^¬ er to form a self-supporting package (10) .

4. The steam drier according to any one of claims 1 to

4. c h a r a c t e r i z e d in that the heating element (2) includes, in parallel to the end pipes (5) and

(6), intermediate pipes (14) extending substantially transversely relative to the first longitudinal pipes (3, 4), the intermediate pipes (14) being fastened by the ends to the first longitudinal pipes (3, 4) so that the first longitudinal pipes (3, 4) are provided in flow connection to each other through the intermediate pipes ( 14 ) .

5. The steam drier according to any one of claims 1 to 4, c h a r a c t e r i z e d in that the end pipes (5, 6) are curved.

6. The steam drier according to any one of claims 1 to 4, c h a r a c t e r i z e d in that the end pipes (5, 6) are straight.

7. The steam drier according to any one of claims 1 to 4, c h a r a c t e r i z e d in that the end pipes (5, 6) are V-shaped.