US3817061A

US3817061A - Heated roll deposit cleaning apparatus

Info

Publication number: US3817061A
Application number: US00289409A
Authority: US
Inventors: A Bruner
Original assignee: Monsanto Co
Current assignee: Monsanto Co
Priority date: 1970-11-12
Filing date: 1972-09-15
Publication date: 1974-06-18
Anticipated expiration: 1991-06-18

Abstract

Steam is jetted against the circumferential path of contact of yarn on a roll heated to above 100*C. This greatly reduces buildup of yarn spin-finish and ''''monomer'''' on the hot roll, thus reducing the frequency at which the process must be interrupted for cleaning the roll.

Description

[ 1 June 18, 11974 [56] References Cited UNITED STATES PATENTS 2,129,274 9/1938 Hartmann et al. 611/205 E X 2,533,103 12/1950 Givens et al. (18/205 E X Primary Examiner-Harvey C. Hornsby Assistant Examiner-Philip R. Coe

[57] ABSTRACT Steam is jetted against the circumferential path of contact of yarn on a roll heated to above 100C This greatly reduces buildup of yarn spin-finish and monomet" on the hot roll, thus reducing the frequency. at which the process must be interrupted for cleaning the roll.

4 Claims, 1 Drawing Figure APPARATUS Inventor: Albert H. Bruner, Pensacola. Fla.

Assignee: Monsanto Qornpany, St. Louis, Mo.

Sept. 15, 1972 Appl. No: 289,409

Related US. Application Data Continuation-impart of Ser No 88,592, Nov. 1970, abandoned.

68/205 E, 118/70 1nt.11)06c 1/08, D06c 7/02 Field of Search.......l..... 118/70; 68/205 E, 5 E, 68/5 D; 8/1493, 151.2

Unite States Patent [19] Burner HEATED ROLL DEPOSIT CLEANING [22] Filed:

1 HEATED ROLL DEPOSIT CLEANING APPARATUS This application is a continuation-in-part of copending application Ser. No. 88,592, filed Nov. 12, 1970, and now abandoned.

The invention relates to reducing buildup of deposits on a heated roll contacting a yarn.

A number of processes involve treatment of a moving yarn with heat for various reasons. Virtually all yarns are coated with a liquid spin-finish composition prior to the heat treatment in order to lubricate the filaments, reduce static, etc. The liquid finish compositions are typically aqueous emulsions of oils, dispersants, emulsitiers, and the like. When such a coated yarn contacts a roll heated to above 100C, a deposit builds up on the roll in the circumferential path or track of the yarn on the roll. The deposit changes the coefficient of fric tion between the yarn and roll, and to some extent reduces the heat transfer from the roll to the yarn. This deposit includes partially degraded components of the finish composition. The deposit may also include various partially degraded oligomers (commonly referred to as monomers") related to the polymer from which the yarn is formed, such as nylon, polyester, acrylics, etc.

According to the present invention, the rate of buildup of this undesirable deposit is substantially reduced by jetting a fluid hotter than 100C. against the path or track of the yarn on the roll, thus reducing the frequency at which the process must beint'errupted to clean the roll.

One principal object of the invention is to provide apparatus for reducing the rate of buildup of the undesirable deposit on a rotating heated roll.

A further object is to provide apparatus of the above character wherein the rate of buildup is reduced by jetting a fluid stream at a temperature greater than 100C. against the path of yarn contact on the roll.

Other objects will in part appear hereinafter and will in part be obvious from the following description in conjunction with the accompanying drawing, wherein the single FIGURE is a perspective view, partially schematic and partially broken away, of the preferred embodiment of the invention.

The FIGURE shows the invention as used in the drawing of a continuous filament yarn such as nylon 66. As illustrated in this context, yam is fed from schematically illustrated yarn supply 22 to pass in several wraps about feed roll 24 and its associated separator roll 26. Yarn 20 has on its surface a conventional spinfinish of the usual oils, antistatic agents, emulsifiers, etc. Supply 22 can be a conventional package of spun yarn, or can be a spinning position, in. which case the spin-finish is applied. by finish roll 23 shortly after the filaments solidify. Feed roll 24 is driven at a given surface velocity by motor 28. Yarn 20 next passes through a slot in insulated chamber and in a plurality of wraps about draw roll 32 and its associated separator roll 34. Draw roll 32 is driven at a surface velocity higher than that of feed roll 24 by motor 36, to draw the yarn. Yarn 20 next passes out of chamber 30 and is wound or otherwise collected by yarn takeup' device 38.

Roll 32 is heated to above 100C, for example by internal heaters energized through electrical leads 40. Tube 42 extends axially parallel to the axisof roll 32, and is positioned between roll 32 and separator roll 34.

Tube 42 extends through the right or rear wall of chamber 30, and is mounted for reciprocation parallel to the axis of roll 32. Slowly rotating cam 44 in cooperation with spring 46 reciprocates tube 42 at a rate of a few cycles (e.g., 5) per minute. A source 48 supplies the heated fluid (preferably steam) under pressure through flexible tube 50 to the interior'of tube 42.

As yarn 20 passes around

rolls

32 and 34, it contacts roll 32 in a series of circumferential paths or tracks. Since yarn 20 takes only a partial wrap about roll 32 during each pass, only a portion of each track is contacted by yarn 20 at any given time, but all portions of each track are repetitively brought into and out of contact with the running yarn 20 as roll 32 rotates. Some of the finish and sometimes some monomefi are deposited on these tracks and tend to be degraded by the heat. According to the invention, jet nozzles or orifices 52 are aligned with and direct streams of heated high velocity fluid onto the portions of the yarn tracks which are not in contact with the yarn at that time, vaporizing or otherwise blasting off most of the deposits before they have time to degrade and adhere to roll 32. The stream impinge against roll 32, as opposed to merely being tangent thereto. Nozzles 52 are positioned near but not touching roll 32. For example, the clearance may be about one-eighth to one-fourth inch. In operation a point on the track on the roll surface repetitively and alternately contacts the yarn and is then impinged against by the gaseous stream.

The heated fluid is preferably continuously discharged against roll 32, particularly if the fluid temperature is different from the'temperature of roll 32. This aids in maintaining a constant temperature of roll 32 by avoiding variable thermal loading on the roll.

Use of the invention does not totally eliminate deposits with commonly used finish compositions. However it materially reduces the rate at which deposits build up. This results in two distinct advantages, the first of which is that the heated roll can be run longer between auxiliary cleanings, thus resulting in less machine down time" and greater productivity. The second advantage is that the roll has a longer service life before the surface must be refinished. The auxiliary cleaning process gradually changes the surface finish characteristics, and hence the surface frictional properties of the roll. By reducing the number of times that the roll must be subjected to auxiliary cleaning in a given period of time, the expensive surface refinishing of the roll is required less often.

Of the various heated fluids tested, steam has been found to be the best, and saturated steam is particularly effective. Hot air is considerably less effective, although it does usually provide to some degree the objects and advantages of the invention.

In the preferred embodiment when treating nylon 66 yarn, orifices 52 have diameters of 0.020 inch and have a length of 0.065 inch. Saturated steam is supplied by supply 48 at 260C. and p.s.i.g. to tube 42. Roll 32 is heated to 200C. by the internal electrical heaters, and has a diameter of 6 inches.

Rolls

24 and 32 may be operated at speeds to draw yarn 20 at normal draw ratios, and at speeds up to 5,000 yards per minute. Although the invention is illustrated in the context of usingthe heated roll as a positively driven draw roll, the invention is not limited to this particular use. The heated roll can be an idler roll (driven by the yarn), and

can be used for relaxing, setting, or otherwise heattreating the yarn.

In order to minimize steam consumption and to insure high velocity in the steam impinging on roll 32, the steam orifices are preferably quite small. To clean an area at least as wide as the tracks made on roll 32 by yarn 20 with a narrow jet stream, steam tube 42 and orifices 52 are reciprocated with a component of motion parallel to the axis of roll 32 by cam 44, as noted above. The axial motion of tube 42 required is small, with about one-fourth to one-half inch being normally sufficient. The steam pressure is not particularly critical, although better cleaning is generally obtained at higher pressures and temperatures. Preferably steam at at least V; sonic velocity is used. The temperature of the gaseous stream is generally not critical, and may be between 100C. and 1,000C. or even higher. Advantageously the gas temperature may be the same as the roll temperature. However, this is not essential since the amount of gas required for cleaning is generally less at higher temperatures than at lower ones, and accordingly the amount of heat added to the roll by the gaseous stream or streams will ordinarily not materially affeet the temperature of the roll. That is to say, ordinarily the heat added to the roll by the hot gas will not be sufficient to maintain the roll at the desired temperature, and that separate means will normally be required for heating the roll.

Chamber 30 is provided with an exhaust line 54 for removing the steam. This largely prevents steam from escaping through the slots by which yarn 20 enters and leaves chamber 30, and subsequently condensing on nearby equipment.

By the term thermally stable yarn is meant a yarn which is not melted or degraded to an undesirable degree by contact with the heated roll. The amount of heat transferred to the yarn during each pass of the yarn across the roll is, for a given roll temperature, a function of the contact time between the yarn and the roll. Ordinarily the roll temperature will be lower than the critical yarn temperature at which the yarn melts or degrades, but it may be higher (up to 500C.) if the contact time is correspondingly reduced. Selection of an appropriate roll temperature and contact time for a given yarn is within the scope of one skilled in the art.

I claim:

1. Yarn treating apparatus, comprising a. a rotating roll;

b. means for heating said roll to a temperature above 0. means for supplying yarn to be treated to said roll whereby said yarn contacts said roll in at least one track extending circumferentially around said roll, said yarn containing on its surface a liquid finish;

d. jet means for impinging on said at least one track a fluid heated to above 100C, said jet means being reciprocated in a path having a component of motion parallel to the axis of said roll; and

e. means for collecting said yarn from said roll.

2. The apparatus defined in claim 1, wherein said fluid is steam.

3. The apparatus defined in claim 1, wherein said jet means continuously jets steam against said at least one track.

4. The apparatus defined in claim 1, wherein said roll and said jet means are mounted within an insulated en-

Claims

1. Yarn treating apparatus, comprising a. a rotating roll; b. means for heating said roll to a temperature above 100*C.; c. means for supplying yarn to be treated to said roll whereby said yarn contacts said roll in at least one track extending circumferentially around said roll, said yarn containing on its surface a liquid finish; d. jet means for impinging on said at least one track a fluid heated to above 100*C., said jet means being reciprocated in a path having a component of motion parallel to the axis of said roll; and e. means for collecting said yarn from said roll.

2. The apparatus defined in claim 1, wherein said fluid is steam.

4. The apparatus defined in claim 1, wherein said roll and said jet means are mounted within an insulated enclosure.