Cover device for a drainage apparatus for a papermaking machine

Abstract

A cover device (10) is disclosed for use in a dewatering shoe or other drainage device of a papermaking machine. The cover device (10) includes a plate (12) of expanded metal which defines a plurality of elongate holes (14, 15, 16, 17, 18, 19, 20 and 21) for the passage therethrough of water as indicated by the arrow (22) removed from a web W disposed on a dewatering screen (24) moving in a machine direction MD relative to the cover device (10). The arrangement is such that the dewatering screen (24) is disposed between the web W and the cover device (10) so that the water (22) is removed from the web W through the dewatering screen (24) and then through the elongate holes (14 to 21).

Claims

1. A cover device for a dewatering shoe of a papermaking machine, said cover device comprising: a plate of expanded metal defining a plurality of elongate holes with an elongate cross-section for the passage therethrough of water removed from a web disposed on a dewatering screen moving relative to the cover device with the dewatering screen being disposed between the web and the plate of expanded metal so that the water is removed from the web through the dewatering screen and then through said elongate holes; a first row of holes of said plurality of elongate holes, each hole of said first row having a first common longitudinal axis; a second row of holes of said plurality of elongate holes, each hole of said second row having a second common longitudinal axis; said first and second common longitudinal axes being disposed spaced and parallel relative to each other; said plate of expanded metal including: a metal bridge disposed between each hole of said first row of holes and an adjacent hole of said first row of holes; a metal connector is disposed between each hole of said first row of holes and an adjacent hole of said second row of holes; said bridge being disposed at a first distance relative to the dewatering screen moving relative to the cover device; said connector disposed adjacent to said bridge being disposed at a second distance relative to the dewatering screen moving relative to the cover device; and said second distance being greater than said first distance so that the dewatering screen slides over and is supported by said bridges during movement of the dewatering screen while moving relative to the cover device.

2. A cover device as set forth in claim 1 wherein said plate has a leading edge and a trailing edge, said leading edge and said trailing edge being disposed parallel and spaced relative to each other.

3. A cover device as set forth in claim 2 wherein said leading edge and said trailing edge are disposed parallel relative to a cross machine direction of the dewatering screen when moving relative to the cover device.

4. A cover device as set forth in claim 3 wherein said common longitudinal axes of said rows of holes are disposed parallel relative to said cross machine direction.

5. A cover device as set forth in claim 3 wherein said common longitudinal axes of said rows of holes are disposed normal relative to said cross machine direction.

6. A cover device as set forth in claim 3 wherein said common longitudinal axes of said rows of holes are disposed at an angle within a range 35 to 55 degrees relative to said cross machine direction.

7. A cover device as set forth in claim 1 wherein a metal bridge is disposed between each hole of said first row of holes and an adjacent hole of said first row of holes.

8. A cover device as set forth in claim 1 wherein a metal connector is disposed between each hole of said first row and an adjacent hole of said second row.

9. A cover device as set forth in claim 1 wherein a first column of bridges being disposed parallel and spaced relative to a second column of bridges; and a column of connectors being disposed parallel and spaced relative to said first and second column of bridges, said column of connectors being disposed between said first column of bridges and said second column of bridges.

10. A cover device as set forth in claim 1 wherein said plate is fabricated from stainless steel.

11. A cover device as set forth in claim 1 wherein said plate is fabricated from stainless steel and coated with ceramic material.

12. A cover device for a dewatering shoe of a papermaking machine, said cover device comprising: a plate of expanded metal defining a plurality of elongate holes with an elongate cross-section for the passage therethrough of water removed from a web disposed on a dewatering screen moving relative to the cover device with the dewatering screen being disposed between the web and the plate of expanded metal so that the water is removed from the web through the dewatering screen and then through said elongate holes; a first row of holes of said plurality of elongate holes, each hole of said first row having a first common longitudinal axis; a second row of holes of said plurality of elongate holes, each hole of said second row having a second common longitudinal axis; said first and second common longitudinal axes being disposed spaced and parallel relative to each other; said plate has a leading edge and a trailing edge, said leading edge and said trailing edge being disposed parallel and spaced relative to each other; said leading edge and said trailing edge are disposed parallel relative to a cross machine direction of the dewatering screen when moving relative to the cover device; said common longitudinal axes of said rows of holes are disposed at an angle within a range 35 to 95 degrees relative to said cross machine direction; a metal bridge is disposed between each hole of said first row of holes and an adjacent hole of said first row of holes; a first column of bridges being disposed parallel and spaced relative to a second column of bridges; a metal connector is disposed between each hole of said first row holes and an adjacent hole of said second row of holes; a column of connectors being disposed parallel and spaced relative to said first and second column of bridges, said column of connectors being disposed between said first column of bridges and said second column of bridges; each bridge is disposed at a first distance relative to the dewatering screen moving relative to the cover device; each adjacent connector is disposed at a second distance relative to the dewatering screen moving relative to the cover device; said second distance being greater than said first distance so that the dewatering screen slides over and is supported by said bridges during movement of the dewatering screen while moving relative to the cover device; and said plate is fabricated from stainless steel and coated with ceramic material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of a cover device according to the present invention for a dewatering shoe of a papermaking machine;

(2) FIG. 2 is a side elevational view of the cover device shown in FIG. 1;

(3) FIG. 3 is a perspective view of a cover device according to an alternative embodiment of the present invention;

(4) FIG. 4 is a perspective view of a cover device according to another embodiment of the present invention;

(5) FIG. 5 is an enlarged sectional view taken on the line 5-5 of FIG. 4;

(6) FIG. 6 is a perspective view of a cover device according to a preferred embodiment of the present invention; and

(7) FIG. 7 is a top plan view of the cover device shown in FIG. 6.

(8) Similar reference characters refer to similar parts throughout the various views and embodiments of the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

(9) FIG. 1 is a perspective view of a cover device generally designated 10 for use in a dewatering shoe or other drainage device of a papermaking machine. As shown in FIG. 1, the cover device 10 includes a plate 12 of expanded metal which defines a plurality of elongate holes 14, 15, 16, 17, 18, 19, 20 and 21 for the passage therethrough of water as indicated by the arrow 22 removed from a web W disposed on a dewatering screen 24 moving in a machine direction as indicated by the arrow MD relative to the cover device 10. The arrangement is such that the dewatering screen 24 is disposed between the web W and the cover device 10 so that the water 22 is removed from the web W through the dewatering screen 24 and then through the elongate holes 14 to 21. A first row generally designated 26 of holes 14 to 17 of the plurality of elongate holes 14 to 21 is arranged such that each hole such as hole 14 of the first row 26 has a first common longitudinal axis 28. A second row generally designated 30 of holes 18 to 21 of the plurality of elongate holes 14 to 21 is arranged such that each hole such as hole 18 of the second row 30 has a second common longitudinal axis 32. Also, the first and second common longitudinal axes 28 and 32 are disposed spaced and parallel relative to each other.

(10) FIG. 2 is a side elevational view of the cover device 10. As shown in FIG. 2, the plate 12 has a leading edge 34 and a trailing edge 36. The leading edge 34 and the trailing edge 36 are disposed parallel and spaced relative to each other. Also, the leading edge 34 and the trailing edge 36 are disposed parallel relative to a cross machine direction as indicated by the arrow CD shown in FIG. 1 of the dewatering screen 24 when moving as indicated by the arrow MD relative to the cover device 10.

(11) Additionally, the common longitudinal axes 28 and 32 of the rows of holes 14 to 17 and 18 to 21 respectively are disposed parallel relative to the cross machine direction CD as shown in FIG. 1.

(12) FIG. 3 is a perspective view of a cover device generally designated 10a according to an alternative embodiment of the present invention. As shown in FIG. 3, the common longitudinal axes 28a and 32a of the first and second rows 26a and 30a respectively of holes 14a to 17a and 18a to 21a respectively are disposed normal that is 90 degrees relative to the cross machine direction CD.

(13) FIG. 4 is a perspective view of a cover device generally designated 10b according to another embodiment of the present invention. As shown in FIG. 4, the common longitudinal axes 28b and 32b of the first and second rows 26b and 30b respectively of holes 14b to 17b and 18b to 21b respectively are disposed at an angle A which is within a range 35 to 55 degrees and more specifically, 45 degrees relative to the cross machine direction CD. In FIG. 4, the dewatering screen 24 and web W have been removed for clarity.

(14) Those skilled in the art will appreciate that the plate 12b may be formed by welding or otherwise joining together in abutting relationship several sheets of the expanded metal and then cutting the same to provide a leading and trailing edge 34 and 36 respectively as shown in FIG. 2. The plate 12 shown in FIG. 2 can also be bent to conform to the contour of the dewatering shoe 38 shown in FIG. 2. Additionally, although in the preferred embodiment of the present invention, the axes 28b and 32b are shown within a range of 35 to 55 degrees and preferably 45 degrees relative to the CD, any angle of the axes 28b and 32b relative to the cross machine direction CD could be used within the concept of the present invention.

(15) Moreover, as shown in FIG. 4, a metal bridge 40 is disposed between each hole such as 14b of the first row 26b of holes 14b to 17b and an adjacent hole such as 15b of the first row 26b of holes 14b to 17b.

(16) Furthermore, a metal connector 42 is disposed between each hole such as 15b of the first row 26b and an adjacent hole such as 19b of the second row 30b of holes 18b to 21b.

(17) According to the present invention, a first column generally designated 44 of bridges 40, 46, 47, 48 and 49 is disposed parallel and spaced relative to a second column generally designated 50 of bridges 51, 52, 53, 54 and 55. Also, a column generally designated 56 of connectors 42, 58, 59, 60 and 61 is disposed parallel and spaced relative to the first column 44 of bridges 40b, 46b to 49b and the second column 50 of bridges 51 to 55. The column 56 of connectors 42 and 58 to 61 is disposed between the first column 44 of bridges and the second column 50 of bridges.

(18) FIG. 5 is an enlarged sectional view taken on the line 5-5 of FIG. 4. As shown in FIG. 5, each bridge 40, 46 is disposed at a first distance D1 relative to the dewatering screen 24 moving relative to the cover device 10b. Also, each adjacent connector 42, 58 is disposed at a second distance D2 relative to the dewatering screen 24 moving relative to the cover device 10b. The second distance D2 is greater than the first distance D1 so that the dewatering screen 24 slides over and is supported by the bridges 40, 46 during movement of the dewatering screen 24 while moving relative to the cover device 10b.

(19) Preferably, the plate 12b is fabricated from stainless steel.

(20) Additionally, the plate 12b is coated with ceramic material.

(21) FIG. 6 is a perspective view of a cover device generally designated 10c according to a preferred embodiment of the present invention. As shown in FIG. 6, the common longitudinal axes 28c and 32c of the first and second rows 26c and 30c respectively of holes 14c to 17c and 18c to 21c respectively are disposed at an angle Ac which is within a range from 35 to 95 degrees relative to the cross machine direction CD. In FIG. 6, the dewatering screen 24 and web W have been removed for clarity.

(22) According to the preferred embodiment of the present invention as shown in FIG. 6, a first column generally designated 44c of bridges 40c and 47c, is disposed parallel and spaced relative to a second column generally designated 50c of bridges 51c and 53c. As shown in FIG. 6, each column such as column 44c is staggered or offset relative to an adjacent column 50c. The staggering or offset configuration is such that each hole such as hole 14c is staggered or offset relative to a diagonally adjacent hole 18c. Also, a row generally designated 100 of connectors 102, 103 and 104 is disposed parallel and spaced relative to the first row 26c and second row 30c of holes 14c to 17c and 18c to 21c respectively. The diagonal offset has greatly reduced a streaking effect in the resultant web thus resulting in a web having enhanced features when compared with webs formed on prior art arrangements.

(23) FIG. 7 is a top plan view of the cover device 10c shown in FIG. 6. As shown in FIG. 7, the hole 14c is offset or staggered relative to the diagonally adjacent hole 18c of an adjacent row 30c.

(24) In operation of the invention according to the present invention, the cover device 10 is fabricated from a sheet of expanded stainless steel and is coated with a layer of wear resistant ceramic material particularly on the side of the cover 10 coming into contact with the moving dewatering screen 24.

(25) The present invention provides a unique cover device that has many advantages over the prior art arrangements and which greatly reduces the cost of manufacture of such cover device.