JPH034830B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for drying a moving web, in particular a radiant heater arranged transversely to the moving web, which can be individually controlled to provide a uniform moisture profile. Regarding.

Knneth Ostrow et al., filed on July 6, 1982, entitled Transverse Web Dryer;
As described in U.S. Patent Application No. 395,864, co-pending with the original U.S. patent application of this application, in papermaking processes where continuously moving sheets of paper are being produced, drying is typically carried out using cylindrical steam drums. However, it is known to be uneven from edge to edge. In other words, stripes are formed.
This results in a product of uneven quality. The aforementioned co-pending Ostrow application discloses the benefits of efficient correction of moisture content variations across a paper web and a control system for efficiently carrying out this purpose. More specifically, the control system operates on the individual dryer modules of the transverse web dryer. The invention discloses and claims the details of the dryer unit itself.

The transverse dryer unit was
As suggested by Rauskolb, US Pat. No. 3,293,770. Here, four elongated burner units are arranged across the moving web.
Each burner unit then has an individual manually operated valve control so that the burner can attempt to remove dry or wet streaks across the web. The use of infrared heaters to dry textiles, paper, etc., such as by the use of fused silica radiant surfaces, is suggested in US Pat. No. 3,864,546 by Cahnman as inventor. Here, the heaters can be pivoted about respective axes extending transversely to the direction of displacement of the web in order to prevent overheating of the web. That is, when the web stops, the heater is pivoted upward.

US Pat. No. 3,499,232 issued to Zimmermann as inventor illustrates a dryer having a removable heating unit. Each heating unit has a heating element that has a fused quartz plate at its bottom adjacent to the moving web that it is drying. The heating module or casing has sufficient mounting gaps such that air flows through the gaps and impinges on the moving web to enhance the drying effect.

Research Inc., Minneapolis, Minnesota.
Apparently producing high density radiant heaters for tungsten filament tubular quartz lamps.
A clean quartz window surrounds the lamp to prevent convective cooling of the workpiece or material being cooled by the air cooling of the heater.

Of course, when providing an effective dryer unit, the ambient conditions are very demanding, for example in paper machines. Thus, for example, a large number of dryer modules with low cost, high strength and high efficiency are provided. It is also desirable that the dryer unit be easily mounted across the width of a relatively large web of moving paper in order to provide an overall drying system that is easily serviceable and not subject to failure.
Failure of such equipment is, of course, very serious as it may require the entire process to be shut down in some situations on paper machines.

It is therefore an object of the present invention to provide an improved apparatus for controlling the moisture curve of a moving web.

In accordance with the above objectives, the apparatus includes an elongated structural member having a length in the transverse direction at least as large as the web and forming the primary structural support for the drying apparatus. The support means receives a plurality of dryer modules in side-by-side relationship and removably supports the dryer modules in position across the web for drying the web. The support means is cantilevered from and secured to the structural member. and fixed support means for rotatably supporting at each end a structural member extending toward the web and having therein means for rotating the dryer module away from the web.

FIG. 1 shows a drying apparatus 1 embodying the present invention.
0 and the drying device 10 is configured to move a moving paper sheet or web 1 with a direction of movement indicated by arrow 12.
1.
In the position shown, the dryer unit contained within the apparatus is in close proximity to the moving web 11, e.g. 1 inch (25.4 mm).
less than Virtual Figure 13 shows the device rotated away from the web to quickly remove the heat source and prevent damage to the individual heating elements in the event of a web tear.

As described in the co-pending Ostrow application, the dryer consists of several dryers in side-by-side relationship across the paper so that individual bands or slices of paper can be individually dried. It has individually controlled heater modules. The apparatus 10 includes several drying units 16a-16g with four heater modules or dryer modules per unit.
includes. Of course, the number of units 16 will vary according to the width of the web, and the numbers shown are merely exemplary. Each cover for units 16a-16g has latches 29a, 29b to facilitate access to the dryer module.

At each end of the drying device there is a support means 17 mounted on fixed vertical supports 18a, 18b, respectively.
There are a and 17b. A hydraulic drive system, indicated at 19, is incorporated into each end support 17a, 17b. When these are activated, the virtual diagram 13
The part of the dryer above the paper is rotated away from the paper, as shown in , and then back again and rotated closer to the paper. This rotation takes place around a large diameter elongated structural member in the shape of a circular conduit, shown in phantom at 21. Square shaped members or other equivalents may also be used. The entire pivoted device is cantilevered around this structural member, which serves as the primary structural support for the drying device. Therefore, the ends of the structural members are connected to the end pieces 1
It is supported in bearings in 7a and 17b.

Each hydraulic actuator unit 19 includes a cylinder 22 fixed to an end support at a pivot point 23. The end 24 of the actuator is pivotally connected to the central portion 13 of the drying device. End 26
shows the extended state of the piston.

In addition to serving as the main structural support for the drying device, the hollow structural member 21 also acts as a conduit for electrical wiring within the device.

Cooling air is provided by a forced air blower 27 coupled by a hose 28 to one of the end panels. Actually, the dryer units 16a to 16
Any end panel can be suitably used to introduce air into g. This side-by-side unit forms an enclosed structure that is a continuous main air plenum 30 (see FIG. 4).

FIG. 2 shows the cover 20 of the broken unit 16g and one of the individual heater modules 31,
Another part is shown. These are supported by a pivoting structure and are replaceable to facilitate repair. Hydraulic actuator 19
is pivotally connected at 24 to the end wall 41 of the central section. The same structure is at the opposite end 17a.

The module 31 has a through hole 34 in the structural member 21.
Pairs 32, 33, etc. of electrical conductors extending outwardly from the heater module itself to the
As detailed in the Ostrow application,
Individually powered and controlled. This electrical conductor is suitable since the typical power output of an individual heater module is 24 kilowatts at 480 volts.
It is quite remarkable in size.

Thus, as can be seen, member 21, in addition to its structural support function, also provides an electrical conductor (through hole 34) for supplying energy to the dryer module.
Support and cool.

To insulate the end supports 17a, 17b from heat, the pivoting central section has a plank 42 of insulating material at each end.

Since the central part of the drying device is pivoted, a pair of bearings 36a, 36b are provided at the ends 17a, 17b. The bearing is shown in detail in FIG. 3, where a fixed bearing support is provided by the wall 37 of the end support 17b providing a mounting block 38, onto which a bearing band 39 is fastened. . The bearing itself is sintered brass, for example a typical journal sleeve bearing.

FIG. 4 is a cross-sectional view of the entire drying unit;
It clearly shows how the device is effectively secured to and cantilevered onto the main structural member 21. Furthermore, it allows the dryer modules 31 to be interchangeably supported in side-by-side relationship. In particular, vane-shaped support portions 43 and 44 extend from and are welded to structural member 21. The lower portion 44 has a shelf 46 on which one end of the heater module 31 rests and is supported. Opposing shelf portions 47 are supported by partially cut away spaced apart brackets 48, shown by dashed lines, which are secured to vane brackets 43. These are spaced apart, for example every fourth unit 16. Between the shelf areas 46 and 47,
There is an open space for a quartz lamp heater 51, each of which contains several dryer units 37 acting on the paper directly below it. The quartz lamp heater 51 of the heater module 31 has an axis that coincides with the direction 12 of the moving web (FIG. 1). The lamp is supplied with energy through terminals 52 and 53 connected across heater 51 and electrical conductor 32. A third electrical conductor 35 provides a safety ground connection.

The top of each dryer module is located in the plenum chamber 5.
6 is a recessed plate 54 with a number of holes 55 (see FIG. 2) for admitting air. Air is of course provided by a forced air blower system through the main air plenum 30. Plenum 5
6 has its bottom side formed by a slotted ceramic plank or tile 57, best shown in FIG. It has about the same number of slots as a quartz lamp heater. Slotted ceramic plate 57 is supported within the frame of the dryer module by ceramic interlocking blocks 59 and 61. Both these ceramic blocks and the tiles themselves can be constructed from materials such as alumina.

Furthermore, the air is picked up by the scoops 49 and 50 (see FIG. 4), which direct the air to both ends 5 of the quartz heater 51 as shown by the arrows.
Turn to 1. The end of the lamp 51 must be kept cooler than the main body since it is the most prone to failure. Scotops ensure proper air flow.

A quartz plate 60 closes the bottom of each heater module 31. The quartz plate 60 is actually divided into two parts 60a and 60b, as best shown in FIG. 6, by a slit 65 which occurs in the center line of the plate 60 parallel to the heater element 51. Furthermore,
Since the quartz plate 60 is held only at its ends by U-shaped end pieces 62 and 63 as shown in FIG. 4, a slit 66 (FIG. 6) is formed between the plates of adjacent heater modules. Slits 65 and 66 allow cooling air to escape into the space between sheet material 11 and quartz plate 60 and then exit from the front and rear of module 31 as indicated by the arrows in FIG.

As partially depicted in FIG. 4, an optical coating 64 may be applied to either side of the fused silica plate 60 to reduce or eliminate the amount of visible light. This is for the benefit of nearby workers, who may be adversely affected or bothered by visible light if this optical coating is not present. Although only one centerline slit 65 is shown in the quartz plate, depending on the application, two or more slits with wider or narrower widths may be used to provide the correct air flow and back pressure. Can be done.

The above configuration has several advantages. It allows for the exhaust of cooling air from the quartz lamp and utilizes this exhaust air to provide relatively cool air between the moving web and the heating module. In other words, relatively cool air is provided between the paper and the heater module. This is because air circulation, as shown in FIG. 6, continuously blows moist air through the slits 65 and lateral slits 66 in the quartz plate from the surface of the web 11 being dried. It's to pay.
There is also a protective purpose to keep the web away from hot heaters, thus reducing the risk of fire. The glass plate prevents the paper or web material from striking the heater element, which, depending on its type, may not have high mechanical strength. Finally, back-flow pressure allows the plenum 56 to provide uniform distribution of air to all modules 31.

Depending on the application, for example, if the heating element does not require protection, the glass plate can be completely removed to allow free flow of air from the quartz lamp to the paper sheet.

FIG. 6 shows a cross-section of a heater module having a recessed top plate 54 with holes for admitting air into the plenum 56, where the air is homogenized by the plenum and then passes through the ceramic heater tiles. Flows equally well through all of the slots 58 in 57. Some quartz heater tubes or lamps 51 are offset somewhat from slot 58 and therefore do not receive direct air flow over them. Additionally, this offset prevents radiant energy from being transmitted through the slots to the plenum chamber 56 near the "line of sight". This air, of course, provides cooling for both heater enclosures, which themselves, being quartz, do not absorb much of the radiant energy except in sufficient quantities to still require cooling.

Figures 7 and 8 show another embodiment of the heating element, now designated 51'. As described in conjunction with FIG. 4, air scoops 49 and 50 are used to specifically direct air to cool the ends of the heater elements. Cooling of these parts of the heater element has been found to be important as they are exposed to high temperatures. As shown in FIG. 4, the heater element is capped with a standard box enclosure available from the manufacturer.

However, as shown in FIG.
All but 7 have been removed. These ends are held by clips 68. An electrical conductor 69 protected by an insulating sleeve 71 extends from each end.

Air flows from one air scoop, for example as shown by arrow 72. narrowed flat part 67
It is believed that due to the constriction (constriction) caused by the central portion of the tube 51', a Ben-Lily effect accelerates the air flow rate or air volumetric flow rate. The critical ends of the heating element are thus cooled more effectively. And this is also true, as discussed above, because the ends 67 are now substantially fully exposed to cooling air without the standard end caps. Note that clip 68 covers only a small portion of the surface area of end 67 to provide better cooling.

Another modification made in the embodiment of FIGS. 7 and 8 is that the insulating heater tile 57 (FIG. 6) has been made solid by removing the slot 58, as best shown in FIG. It has been modified to provide a partition wall 57'. This therefore directs substantially the entire flow of air from the plenum 30 (extending across the fully enclosed structure, see FIG. 4) through the air scoops 49 and 50 first to the heater. Flow over end 67 of element 51' and then over the heater element itself.

After that, of course, as mentioned above, the quartz protection plate 60
includes slits 65 and 66 (FIG. 6) to allow cooling air to escape into the gap between paper 11 and plate 60.

Since the tiles 57' are now solid, the plenum chamber 56 shown in FIGS. 4 and 6 may be omitted;
Alternatively, plate 54 can be solid without holes 55.

Thus, in summary, the use of the structural member 21 to support the remainder of the cantilevered drying apparatus provides
The structure of the dryer unit becomes very simple. Moreover, any individual dryer module 31 can be quickly replaced by simply opening one of the covers 20 and removing the electrical connections. Since the individual quartz heat lamps are held by clips at each end, the quartz heat lamps are easily removed when the heater module is outside the frame. Finally, due to the air circulation through the heater module, the remainder of the drying equipment helps to even out the temperature, prevent hot spots, and generally extend the life of all structural parts.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a device embodying the invention, showing its installation on a paper machine. FIG. 2 is an enlarged partially cutaway top view of a portion of FIG. 1; FIG. 3 is a partial cross-sectional view taken along line 3-3 of FIG. Figure 4 is 4 in Figure 2.
FIG. 4 is a cross-sectional view taken along line -4. 5 is a top view of the heater module portion taken along line 5--5 of FIG. 4. FIG. 6 is a partial cross-sectional view taken along line 6--6 of FIG. 4. FIG.
FIG. 7 is a partial perspective view showing another embodiment of the present invention. FIG. 8 is a partial cross-sectional view of another embodiment, but similar to FIG. 4; 10...Drying device, 31...Dryer module, heater module, 21...Structural member, 17
a, 17b... support means, 18a, 18b... fixed vertical support, 30... main air plenum, 56... plenum chamber, 65... slit, 6
6...slit, 57'... partition, 51'... heater element.

Claims (1)

[Scope of Claims] 1. A moving web drying device comprising a plurality of heater modules having at least the same length as the transverse dimension of the web and arranged next to each other for drying the web. an elongate structural member supporting the dryer module, each dryer module having an elongate heater element spaced adjacent and parallel to the web; a solid bulkhead supported by and permeable to thermal radiation of the heater element; an air plenum connected to all of the heater modules; each comprising forced air means for supplying cooling air to the air plenum and an air passageway between the air plenum and the heater element for flowing air from the air plenum to cool the heater element. and at least one opening formed in the septum to direct air from the air plenum across the heater element and into the air between the web and the septum. web drying equipment. 2. The moving web drying apparatus according to claim 1, wherein the opening formed in the partition wall is a slit parallel to the heater element. 3. According to claim 2, the partition wall is held only at both ends thereof, and additional slits are formed to allow air to flow between adjacent heater modules. moving web drying equipment. 4. The heater element has the shape of a glass tube, both ends of which are flat, and electrical conductors extend from both ends, and the heater element further includes a pair of glass tubes fastened to the flat ends. 2. A movement according to claim 1, characterized in that it has a holding clip, and the flat ends of the glass tube and said clip allow the cooling air to flow freely to cool the glass tube. web drying equipment. 5. Claim 1, characterized in that the partition wall is coated with a paint that blocks visible light.
A moving web drying device as described in Section.