Drying and gas or vapor contact with solids – Apparatus – Rotary drums or receptacles
Patent
1986-02-21
1987-08-18
Makay, Albert J.
Drying and gas or vapor contact with solids
Apparatus
Rotary drums or receptacles
34122, 34123, F26B 1308
Patent
active
046867775
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
This invention relates to improvements in paper web dryers, and is more particularly concerned with preventing sheet flutter in such dryers.
Paper web dryers receive freshly formed paper sheet web from a paper making machine on a porous belt, commonly referred to as a dryer felt. The dryer felt is trained to travel over a series of heated dryer rolls. These rolls may be arranged in a vertical stack or in an alternately offset horizontal arrangement wherein the web-carrying felt travels in a generally serpentine dryer path. In either arrangement, the paper web carried by the felt runs in contact with the perimeter of alternate rolls while the felt runs in contact with the perimeters of the remaining rolls.
In a free span between dryer rolls where the still wet web has travelled in contact with a dryer roll perimeter and the felt runs tangentially toward the perimeter of the next succeeding dryer roll, the web is susceptible to damage from sheet flutter due to the air frictionally drawn into tangent pocket defined by the next succeeding roll perimeter and the felt. That is, since the felt is porous, the air drawn into and substantially trapped in the on-running tangent pocket tends to push through the felt toward the web carried on the outside of the free span there is a tendency to flutter and dislodge the wet web from the felt with damaging results. This condition is especially aggravated at high processing speeds in the drying of maximum width paper webs. The drawn in air tends to be trapped in the tangent pocket.
It is to the alleviation of this problem that the present invention is directed.
An important object of the present invention is to alleviate the problem of sheet flutter in high speed paper sheet web dryers.
Another object of the invention is to provide a new and improved method of and means for vacuuming frictionally indrawn air from on-running tangent pockets in high speed paper web dryers.
In accordance with the principles of the present invention, there is provided for high speed dryers wherein a felt carries a paper sheet web over dryer rolls and the felt forms an on-running tangent pocket with the perimeter of a dryer roll and into which pocket air is frictionally drawn by the on-running roll perimeter and felt tending to cause sheet flutter, a vacuum device comprising an elongate hollow manifold for extending longitudinally within the pocket parallel to the felt and web; and opening means substantially throughout the length of the manifold for vacuuming the air from the pocket into the manifold, and thereby avoiding the sheet flutter.
The present invention also provides a new and improved method of avoiding sheet flutter in high speed dryers.
Other objects, features and advantages of the present invention will be readily apparent from the following description of a representative embodiment thereof, taken in conjunction with the accompanying drawing, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts embodied in the disclosure, and in which:
FIG. 1 is a fragmentary side elevational view of a high speed dryer embodying the invention;
FIG. 2 is an enlarged fragmentary elevational detail view taken substantially along the line II--II in FIG. 1;
FIG. 3 is a sectional detail view taken substantially along the line III--III in FIG. 2;
FIG. 4 is a fragmental elevational detailed view, partially broken away and in section of a vacuum device functionally similar to the vacuum device in FIG. 2, but somewhat simplified in structure; and
FIG. 5 is a sectional detail view taken substantially along the line V--V in FIG. 4.
By way of illustration, there is shown in FIG. 1 a horizontal high speed paper web dryer 5 wherein a paper making felt 7 carrying a paper sheet web 8 from a paper making machine, and travels in a serpentine drying path over heated dryer rolls 9, the construction and operation of which is well known. These dryer rolls are generally steam heated and as the web carrying felt progresses through the dryer,
REFERENCES:
patent: 4190964 (1980-03-01), Schiel
patent: 4202113 (1980-05-01), Kankaanpaa
patent: 4359827 (1982-11-01), Thomas
patent: 4359828 (1982-11-01), Thomas
patent: 4441263 (1984-04-01), Vedenpaa
patent: 4502231 (1985-03-01), Fissmann et al.
patent: 4516330 (1985-05-01), Eskelinen et al.
patent: 4566946 (1986-01-01), Koponen et al.
patent: 4628618 (1986-12-01), Virta et al.
Archer David J.
Beloit Corporation
Campbell Raymond W.
Makay Albert J.
Mathews Gerald A.
LandOfFree
Preventing sheet flutter in paper web dryers does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Preventing sheet flutter in paper web dryers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Preventing sheet flutter in paper web dryers will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1109721