|Publication number||US3846618 A|
|Publication date||Nov 5, 1974|
|Filing date||Mar 9, 1972|
|Priority date||Mar 9, 1972|
|Also published as||CA987716A1, DE2311922A1, US3841911|
|Publication number||US 3846618 A, US 3846618A, US-A-3846618, US3846618 A, US3846618A|
|Original Assignee||Air Knife Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (20), Referenced by (3), Classifications (22)|
|External Links: USPTO, USPTO Assignment, Espacenet|
PATENTEDHOV 5 I974 lia ll llulll SHEET 2 0F 3 PATENTEDHU :914. 3,846,618
SHEET 30? 3 EXTERNAL A\ $2. S LJPPLY 2O such a problem is the entanglement of waste material about the axle of'a caster such as are used on carts and the like in textile mills.
Heretofore, the removal of such textile waste material has conventionally been accomplished through the use of a knife or other sharp-edged instrument. At least two difficulties are introduced by such an attempt at removal, namely difficulty in gaining access to the textile waste material wrapped about a caster axle or the like and damage to the apparatus from which the textile waste material is being removed. The latter difficulty is particularly important with removal of textile waste material from bobbins, spools or the like.
The present invention overcomes the difficulties and deficiencies of prior methods and apparatus from removing heat degradable textile waste material by use of a flowing stream of heated air which may readily penetrate into confined spaces and remove the waste material therefrom and-which does not damage the apparatus from which the tenaciously adhered heat degradable textile waste material is being removed.
It is an object of this invention to protect an electrical resistance heater used to heat a flowing stream of air to an elevated temperature against premature failure otherwise possibly occurring by coordinating the electrical energization of the heater with the delivery of a flowing stream of air therethrough to be directed against waste material to be removed. In realizing this object of the present invention, operative interconnection with both the means by which the flowing stream of air is delivered and the electrical resistance heater is established and energization of the electrical heater in the absence of delivery of air is substantially precluded.
A further object of this invention is to provide, in a method of removing tenaciously adhered heat degradable textile waste material, for the self-limiting of the temperatures attained by an electrical resistance heater. In accomplishing this object of the present invention, a flowing stream of air at a predetermined volume rate of flow is delivered to and through an electrical resistance heater having a positive temperature coefficient resistance element. Due to the variance in the resistance of the heater with temperature, the wattage of power consumed by the heater and thus the temperature attained by the heater have a tendency towards self-limitation. As the temperature of the heater rises and the wattage of power consumed is reduced, an equilibrium is reached which, with flow rates as provided by this invention, precludes destructive heating of the resistance element.
Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIG. 1 is a perspective view of a first embodiment of apparatus in accordance with this invention;
FIG. 2 is an elevation view of the apparatus of FIG. 1 with a coverplate removed to reveal components of the apparatus mounted within a housing;
FIG. 3 is an elevation view, partially in section, taken generally as indicated by the line 3-3 in FIG. 2',
FIG. 4 is a plan view, partially in section, through a portion of the apparatus of FIG. 1 taken generally as indicated by the line 4-4 in FIG. 1;
FIG. 5 is an enlarged elevation view, in section, through a portion of the apparatus shown in FIG. 4, taken generally as indicated by the line 5-5 in that figure;
FIG. 6 is a section view taken generally as indicated by the line 6-6 in FIG. 5;
FIG. 7 is an enlarged elevation view, in section, taken generally as indicated by the line 7-7 in FIG. 4;
FIG. 8 is a sectional view taken as indicated by the line 8-8 in FIG. 7;
FIG. 9 is a schematic drawing of the apparatus of FIG. 1;
FIG. 10 is a view similar to FIG. 1, showing a second embodiment of the apparatus of this invention;
FIG. 11 is a detail view showing a pressure responsive electrical switch means incorporated in the apparatus of FIG. 10; and
FIG. 12 is a schematic diagram similar to FIG. 9 and showing the apparatus of FIG. 10.
While first and second embodiments of apparatus in accordance with this invention have been illustrated in the accompanying drawings and will be described in detail in the disclosure which follows, it is to be understood at the outset that the illustration and disclosure of preferred embodiments of this invention are to be construed broadly and not to be taken as limiting upon the scope of apparatus and methods as contemplated by this invention.
Referring now broadly to the accompanying drawings, the embodiment illustrated in FIGS. 1-9 is particularly intended for use in circumstances where electrical power is readily available at locations where the removal of tenaciously adhered heat degradable textile waste material is to be performed and incorporates an air compressor as a means for delivering a flowing stream of air. The second embodiment of apparatus in accordance with this invention, as illustrated in FIGS. 10-12, is particularly contemplated as useful in circumstances where a central supply of compressed air is readily available at locations where the removal of tenaciously adhered heat degradable textile waste material is to be performed. The embodiment of apparatus in accordance with this invention illustrated in FIGS. 10-12 is arranged for connection with such a factory air supply, as will be brought out more fully hereinafter. The disclosure which follows will be directed first to the embodiment'of FIGS. 1-9 and will then turn to the embodiment of FIGS. 10-12.
Practice of the method of this invention in a location within a textile plant or the like is facilitated, in the first embodiment of this invention, by mounting the components of the apparatus generally indicated at 20 in or connected with a housing 21 having a handle 22 by which the apparatus may be carried to a location of use. Within the housing 21 is an electrically driven air compressor 24, illustrated as being of the type having two diaphragms oscillated by connection with an electrical motor. The air compressor 24 delivers compressed air into a flexible conduit 25 which extends from within the housing 21. Where a double diaphragm compressor is used, a characteristic flow rate of compressed air delivered from the compressor 24 would be approximately one cubic foot per minute at a pressure of pounds per square inch. Satisfactory operation has been obtained where a single diaphragm compressor was used and approximately four-tenths of a cubic foot per minute was delivered. Thus, it is believed that an appropriate range of volumes of air flow would be upward from at least about four-tenths cubic foot per minute (CFM). The conduit 25 is sized to pass such flows and pressures substantially unimpedingly, so as to make such flows and pressures available for impingement against the waste material to be removed.
In addition to the compressor 24, an electrical cord reel 26 is mounted within the housing 21 to permit a power cord 28 to be withdrawn from the housing 21 and electrically connected with appropriate line source of electrical current. By means of the power cord 28, electrical power is supplied to'the compressor 24 and to other circuit elements of the apparatus 20, under the control of the control means as will be described more fully hereinafter.
Air delivered through the conduit 25 passes to a manipulable handle 29 which mounts an electrical resistance heater means generally indicated at 30. The electrical resistance heater means 30 has a metallic sheath 31 having mounted in one end thereof a ceramic core 32 (FIGS. 7 and 8). The ceramic core 32 has a plurality of longitudinally directed openings extending therethrough,with a resistance wire 34 coiled within each of the passageways. Upon electrical energization of the resistance wire 34, the wire is raised to an elevated temperature for heating the air flowing therethrough.
Preferably, the heater means 30 is arranged with an air flow entering section housed within the handle 29 andwith a heater section which extends forwardly from the handle 29 (FIG. 4). Thus, an operator manipulating the handle 29 so as to direct the flow of air issuing from the apparatus toward textile waste material to be removed is protected against contact with that portion of the heater means 30 which may attain an elevated temperature. At the extreme forward end of the heater means 30, a provision is made for the attachment of a separable flow directing nozzle 35, by means of a compression nut 36 secured thereto, a compression union 38, and a compression nut 39 which is secured to an outlet tube 40 of the heater means 30.
In order to supply electrical current to the heater means30, electrical conductors 41, 42, 43 extend the length of the air conduit 25 and are held in wrapped relation thereto by a spiral wrapping 45 which extends thereabout.
In order to protect the resistance wire 34 of the electrical heater means from premature degradation and melting otherwise possibly occurring from excessive heating thereof, this invention contemplates the inclusion of control means of a particular type and the employment of resistance elements of a particular type. Turning first to the control arrangements, control means are operatively interconnected with the compressor 24 which delivers air and with the electrical resistance heater 35 for coordinating electrical energization of the heater with delivery of the flowing stream of air. As schematically represented in FIG. 9, such a control arrangement includes an electrical switch means 46 electrically connected between the power cord 28 and the compressor 24 and heater 30. By means of a parallel connection of the conductors leading to the heater means 30 and'to the compressor 24, energization of the heater prior to energization of the compressor is not possible. Due to the temperature rise characteristics of the heater as compared to the flow characteristics of the compressor, the heater 30 will not reach an elevated temperature until after such time as the flow of air from the compressor 24 has begun. The electrical circuitry includes a fuse 48 for protecting against excessive current requirements and a pilot light 49 for indicating to an operator that the unit is operatmg.
It has been found desirable to provide for the possibility of varying the flow of current to the heater 30 and thereby varying the temperature at which air is delivered against textile waste material to be removed. To this end, the control circuitry preferably includes means for varying at least one characteristic of the electrical current flowing to the electrical resistance heater. As schematically illustrated in FIG. 9, a variable resistance 50 is inserted in the conductor 42 leading to the heater 30. In preferred practice of this invention, a thyristor circuit is employed to modulate the phase relation of electrical power delivered to the resistance heater in a manner known to persons familiar with such electronic devices. By way of example and not by way of limitation, such circuits are disclosed in Paragraph 9.4.2 of the SCR Manual, Fourth edition, published by the Semi-conductor Products Department of General Electric Company.
In, practicing the method of the present invention in removing tenaciously adhered textile waste material by directing a flowing stream of heated air thereagainst, it has been discovered that both thermoplastic and nonthermoplastic textile waste materials may be removed. Where the removal of thermoplastic textile materials such as polyester yarns and the like is being practiced, it is desirable that the temperature of the heated air be at least about the softening temperature of the textile material. In instances where the textile material includes or consists of non-thermoplastic material, removal has been found to proceed most readily where the air has been heated to a temperature of at least about l,000 F. Accordingly, heating of the air in accordance with this invention preferably follows the latter practice so as to be equally applicable to the removal of. thermoplastic and non-thermoplastic textile waste materials.
In choosing an electrical resistance heater for heating the air in accordance with this invention, the wattage of the electrical resistance heater is determined from a formula in which kilowatts of power required equal the weight of air delivered per hour times 0.24 times the number of degrees F. by which the temperature of the air is raised divided by 3,4l2. It is preferred that the wattage'requirement for the heater be approximated from the formula Kilowatts CFM Temperature Rise Above Ambient/3,000.
In order to further protect the electrical resistance heater in the apparatus of this invention against premature failure otherwise possibly occurring, the material from which the resistance wire 34 is formed is chosen from among those materials which have a positive temperature coefficient of resistance. That is, those materials which have an increasing resistance as the temperature of the material increases. As applied in the apparatus of this invention, such a resistance heater has a selflimiting characteristic in that the increasing resistance of the wire decreases the power required and flowing therethrough thereby reducing the wattage delivered to the flowing stream of air and limiting the upper temperature attained by the air. Preferably, the material from which the coils 34 of the heater are formed exhibits such a characteristic at temperatures of approximately l,200 F. and may be chosen from among alloys of nickel and platinum.
In an operating embodiment constructed in accordance with FIGS. 1-9, and operating within the parameters in described hereinabove, heated air is directed against waste material to be removed by passage from the nozzle means formed by the handle 29, heater 30 and outlet tube 35 with a velocity of at least about 8,000 feet per minute. Such velocities, when within volume and temperature ranges as described hereinabove, does not adversely effect textile apparatus such as bobbins, casters and the like from which tenaciously adhered heat degradable textile waste material is to be removed. However, such velocities, volumes, and temperatures of heated air are effective to entirely remove such residues.
While this invention has been described to this point with reference to the structure illustrated in FIGS. 1-9 which is particularly intended for operation by connection to a source of electrical power, this invention also contemplates an alternative embodiment to be used where an external air supply is available. Such a second embodiment is illustrated in FIGS. -12, where components comparable to those of the first embodiment described hereinabove are identified by same reference characters with the addition of prime notation. The present disclosure will be directed particularly to the distinctions between the embodiments rather than repeating at length the common characteristics thereof.
The apparatus of FIGS. 10-12 includes an air supply conduit 51 provided with an appropriate coupling 52 for attachment with an external air supply such as is conventionally found in textile mills and the like. Air entering the apparatus 20' through the conduit 51 is filtered in a filter 54 and is delivered to a pressure regulator 55 having a manually operable handle 56 extending through the housing 20'. By manipulation of the handle 56, the pressure at which air is delivered to the conduit and thus to the heater means may be selected.
Downstream of the pressure regulator 55 is provided a pressure responsive switch means generally indicated at 58 (FIGS. 11 and 12) which is reponsive to the presence of a flowing stream of air passing through conduit 25 to the heater means 30'. In the presence of the flowing stream of air, an associated electrical contact set 59 is closed to permit energization of the heater 30'. Absent the flowing stream of air, contact set 59 is opened to preclude energization of the electrical heater.
In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only, and not for purposes of limitation.
That which is claimed is: 1. Apparatus comprising: manually portable housing means for enclosing components of the apparatus and having handle means for accommodating ready portability to a location of use, electrical supply conducting means extensible from within said housing means for delivering electrical current through said housing means, elongate flexible air supply conduit means extending from said housing means and connectable with an external supply of pressurized air for delivering through said housing means a flowing stream of air having a predetermined volume rate of flow, manipulable handle means for manual control over the direction of air, elongate flexible air delivery conduit means extending between said housing means and said handle means for conducting the flowing stream of air from said housing means to said handle means in substantially unimpeded flow and for permitting application thereof at locations remote from said housing means, electrical resistance heater means extending from said handle means and interposed in the flow path of said flowing stream of air for heating air to an elevated temperature, electrical delivery conducting means extending between said housing means and said handle means for conducting electrical current to said heater means, means for binding said delivery conducting means and said delivery conduit means together into a single bundle extending between said housing means and said handle means, nozzle means extending from said heater means for directing heated air, and control means mounted within said housing means and operatively interconnected with said conduit means and said conducting means for coordinating delivery of electrical current and air to said heater means and including: air pressure electrical switch means interposed between said supply conduit means and said delivery conduit means for preventing energization of said heater means in the absence of the flowing stream of air and thereby protecting said heater means against failure otherwise possibly occurring due to energization thereof while no air is flowing therethrough, means for adjustably regulating the pressure at which the flowing stream of air is delivered to said electrical heater means and thereby for varying the velocity at which heated air issues from said nozzle means, and means for varying at least one characteristic of the electrical current flowing to said heater means and thereby varying the temperature at which air is delivered through said nozzle means.
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|Citing Patent||Filing date||Publication date||Applicant||Title|
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|U.S. Classification||392/476, 34/201, 392/488, 392/502, 239/133, 392/384|
|International Classification||B05B1/00, F24H3/04, H05B3/58, B05B1/24, D01H11/00, H05B3/54|
|Cooperative Classification||D01H11/005, F24H9/1872, H05B3/58, F24H3/0405, B05B1/24|
|European Classification||F24H9/18B2A, B05B1/24, H05B3/58, D01H11/00B, F24H3/04B|