US2779105A

US2779105A - Hot air dryer

Info

Publication number: US2779105A
Application number: US373242A
Authority: US
Inventors: Arthur L Park
Original assignee: Saco Lowell Shops
Current assignee: Saco Lowell Shops
Priority date: 1953-08-10
Filing date: 1953-08-10
Publication date: 1957-01-29
Anticipated expiration: 1974-01-29

Description

Jan. 29, 1957 A. L. PARK 2,779,105

HOT AIR DRYER Filed Aug. 10. 1953 P 35 INVENTOR.

ATTORNEV Unit nor Am DRYER Application August 10, 1953, Serial No. 373,242

(Ilairns. (Cl. 34-455) This invention relates to hot air dryers and more particularly to a novel hot air dryer especially suitable for use in drying an extended sheet of sized textile yarns as in a slasher.

In the drying of textile yarns such as cotton or Wool, particularly in a so-called wet splitting slasher, it is desirable to keep the several thousand individual yarns of the yarn sheet separated from one another as much as possible, and particularly so in the initial stages of drying the sized yarns to a non-tacky condition. Various complicated means have been proposed for achieving this result, but the most practical approach to the problem has been by the use of a hot air type of dryer which would allow some vertical separation of the yarn sheet as well as the horizontal separation common to both hot air and cylinder dryers. Such use of vertical separation made possible by the use of a hot air dryer has greatly aided in keeping separate the individual yarns while the size coating was dried to give a superior yarn less subject to breaking and shedding in the loom.

As slasher speeds and capacities increased, however, the use of hot air dryers began to present a problem due to the tendency of such dryers to condense the yarn sheet laterally, especially at the outer edges, causing the yarns to come in contact with one another. This effect resulted not only in substantially slower drying of the yarns but, more important, caused the yarns to stick together with resultant problems in the loom. Fine yarns under low tensions, especially with the higher dryer air velocities necessary to secure high production rates, were particularly susceptible to twisting around each other, with the yarn sheet sometimes assuming a rope-like appearance at the edge portions.

Thus, heretofore, the dryer air velocities have been limited by the amount of lateral condensation of the yarn sheet which could be tolerated. This has required that the size of the hot air dryer be increased in order to achieve desirable high dryer speeds and capacities, and the resultant high speed, high capacity dryers have become too large for use in many locations.

Accordingly, it is an object of the present invention to provide a novel high capacity hot air dryer of reduced size as compared to heretofore known dryers having similar capacities.

A particular feature of my novel dryer is its ability to dry separated yarn sheets without any lateral condensation whatsoever or with a degree of lateral expansion if.

so desired.

It is a further feature of my novel dryer that it may readily be adjusted according to the nature of the yarn sheet to be dried and its speed of travel.

For the purpose of explaining a preferred embodiment of my invention, reference is made to the following detailed description, together with the accompanying drawings, in which:

; Fig. 1 is a somewhat diagrammatic plan view of the novel dryer of my invention;

rates Patent 2,779,105 Patented Jan. 29, 1957 head end (not shown) being provided for moving the extended yarn sheet S through the dryer.

A pair of plenum chambers are mounted horizontally in said enclosure with their working faces opposed, and provide the air distributing means for the dryer, the upper plenum chamber 10 of said pair being mounted adjacent the top of said enclosure and the lower plenum chamber 12 of said pair being mounted below in opposed spaced relation from upper plenum chamber lit, the space between the plenum chambers thus forming a horizontal passage for the extended sheet of yarns S. Both of said plenum chambers are spaced from the sides of said enclosure and preferably from the output end thereof.

The

plenum chambers

10 and 12 are identical in construction and include a generally rectangular enclosure having horizontal working surfaces forming upper and lower surfaces of the passage through which the sheet of yarns passes. The working surfaces of said chambers have a plurality of transversely extending horizontally spaced members 14 forming a plurality of louvres 16 extending transversely of the dryer, the louvres forming openings through which the drying air is distributed over the extent of the yarn sheet S, such an air distributing means providing a smooth non-turbulent air flow which is most effective in its drying action of the yarns passing between and spaced from said surfaces. In order to provide generally uniform air flow within the plenum chamber itself so that each louvre 16 is provided with air at substantially the same pressure, the top and bottom of said chambers are constructed close together at the end opposite the input end of such chamber.

The pair of plenum chambers are provided with a heater and blower 18 having

output ducts

20 and 22 to

plenum chambers

10 and 12, respectively, and a return duct 24 from the end of the yarn passage back to said heater and blower to provide heated air to said plenum chambers and to exhaust the air from the yarn input end of the yarn passage, thus providing a flow of air countercurrent to and along the direction of movement of said yarn sheet. Further means are provided for continuously exhausting moisture laden air from said dryer and for intake of fresh air. Accordingly, an exhaust duct 26 is provided connected to the yarn passage return duct 24, said duct being provided with a damper 28 which may be operated by any suitable means, not shown. When such exhaust damper is open to allow air to be exhausted from the dryer, fresh air is drawn into said dryer through opening 6 therein. The blowers of said heater and blower mechanism are well understood by those skilled in the art and may be driven by any suitable means herein shown as an electric motor 30.

According to my invention, to prevent lateral condensation of the yarn sheet as it passes through the dryer, I have provided air deflecting means at the sides of the yarn passage spaced outwardly from the sheet of yarns, such air deflecting means acting to displace laterally outwardly the yarns near the outer edges of the yarn sheet, thus enabling me to use high dryer air velocities and so reduce the physical size vof a dryer'of a given capacity.

A simple and effective air deflecting means may be provided by a plurality of bafiie plates 32 mounted within the enclosure 2 at the sides of the yarn passage outside of the side surfaces of

plenum chambers

10 and 12, the surfaces of such baffle plates being generally vertical with their inner edges 34 displaced forwardly from their outer edges 36 toward the flow of air created by heater and blower 1% through the yarn passage. For example, if the air flow is countercurrent to the direction of movement of the sheet of yarn, as is preferred, the inner edges 34 will be displaced toward the yarn output opening 6 in enclosure 2.

Since the optimum angle of displacement of the baffle plates 32 and the optimum spacing of their inner edges 34 from the outer edges of the yarn sheet S will be determined by the nature of the yarn sheet to be dried and the operating characteristics of the dryer, 1 have provided a bafiie plate adjusting means (Fig. 3) in which said baffie plates are mounted, said means comprising a pair of relatively movable angle irons, with the base webs 45 in stacked position, the inner upstanding web 37 of the inner angle iron and the outer upstanding web 38 of the outer angle iron having slots 4% and 42, respectively, adapted to receive a baffle plate 32. A slot 44 is provided in each of the base webs 45 of said angle irons to permit relative adjustment of the slots 4%) and 42 to a desired displaced relation, at which said angle irons may be locked by a machine screw 46 which also serves to mount said angle irons on said enclosure 2.

in operation, with a sheet of yarns S being moved through the passage between the opposing working faces of

plenum chambers

10 and 12 as by a conventional slasher head end, the baffle plates 32 are adjusted at say a displacement angle of 45 to the longitudinal axis of the yarn sheet with their inner edges an inch or two from the outer edge of the yarn sheet near the input end of the dryer. The edge of the yarn sheet along the entire extent of the baffle plates will then expand from its normally condensed condition and the lateral spacing of the individual yarns from one another may be maintained or even increased somewhat during the passage of the yarn sheet through my novel hot air dryer.

Although I do not wish to be bound thereby, I believe that the action of the bafiie plates to expand the yarn is due to the Bernoulli efiect, that is, the baffle plates act much as does an airfoil and create a region of reduced pressure along their inner surface behind their inner edge 34. Thus, the angle of displacement from the direction of air flow through the yarn passage between the plenum chambers can be considered as an angle of attack with the baffle plate inner edge 34 as the leading edge. Under such conditions, there will be created a force generally perpendicular to the baffie plate, which force will act to move the yarns near the outer edge of the yarn sheet toward the baffle plate. The angle does not in practice appear to be critical, as I have effectively employed angles from 20 up to 80; Since the effective force created by the baflle plate falls ofi rapidly with distance, however, the leading inner edge 34 of the plate should be quite close to the outer edge of the yarn sheet, say 1 or 2 inches, but in no event more than about 5 inches with dryer air velocities of about 800 F. P. M. The outward displacement of the yarn edge may be increased by decreasing the distance between the baifle plate inner edge 34 and said yarn, but if such distance becomes much less than inch there is danger of the yarns,

being damaged by contact with the bafile plates.

It will be seen that I have provided a novel high capacity hot air'dryer which for the first time makes possible the drying of yarn sheets without any lateral condensation thereof, and one which may readily be adjusted to accommodate almost any conditions. Although I have shown and described herein a preferred embodispirit of my invention and the scope of the appended claims.

I claim:

1. A hot air dryer for continuously drying an extended sheet of yarns passing therethrough comprising air distributing means in opposed spaced relation forming a passage for an extended sheet of yarns moving there-between, blower means for providing a how of air along said sheet of yarns, and a plurality of spaced air deflecting bafile plates at the side of said passage and spaced from said yarn sheet to deflect outwardly said fiow of air near the sides of said passage and displace laterally outwardly the outer edge portions of said yarn sheet, the surface of said baffie plates being generally perpendicular to the surface of said yarn sheet and with their inner edges displaced from their outer edges in a direction toward said flow of air.

2. A dryer as claimed in claim 1 in which said air distributing means includes a pair of plenum chambers each having a working face comprising a plurality of transversely extending spaced members providing a plurality of louvers.

3. A dryer as claimed in claim 1 further having baffle plate adjusting means for adjusting the degree of displacement of said bathe plate edges and the spacing of said inner edges from said yarn sheet to vary the outward lateral displacement of said yarn sheet.

4. A hot air dryer for continuously drying an extended sheet of yarns passing therethrough comprising a pair of plenum chambers with their working faces in opposed spaced parallel relation forming a passage for an extended sheet of yarns moving therebetween, heater and blower means for supplying heated air to said plenum chambers and exhausting air from one end of said passage to provide a flow of air along said passage, and a plurality of spaced air deflecting baffie plates at the sides of said passage and spaced from said yarn sheet to deflect outwardly said flow of air near the sides of said passage and displace laterally outwardly the outer edge portions of said yarn sheet, the surface of said bafiie plates being generally perpendicular to the working faces of said plenum chambers, and with their inner edges displaced from their outer edges in a direction toward said flow of air.

5. A hot air dryer for continuously drying an extended sheet of yarns passing therethrough comprising an insulated enclosure, a pair of plenum chambers mounted within said enclosure with their working faces horizontal and in opposed spaced relation forming a horizontal passage for an extended sheet of yarns moving therebetween, heater and blower means for supplying heated air to said plenum chambers and exhausting air from the yarn inputend of said passage to provide a how of heated air along said sheet of yarns generally countercurrent thereto, a plurality of spaced air deflecting bafiie plates mounted within said enclosure at the sides of said passage and spaced from said yarn sheet to deflect outwardly said countercurrent flow of air near the sides of said passage and displace laterally outwardly the outer edge portions of said yarn sheet, the surface of said baffle plates being generally vertical, and with their inner edges displaced from their outer edges toward said countercurrent flow of air.

References Cited in the tile of this patent UNITED STATES PATENTS 1,737,015 Merrill Nov. 26, 1929 2,083,141 Buck June 8, 1937 2,303,019 Hanson Dec. 22, 1942 2,574,083 Andrews Nov. 6, 1951 2,601,080 Andrews June 17. 1952