US2622306A - Strand blower - Google Patents

Description

Dec. 23, 1952 M. c. ANDERSON 2,622,306

STRAND BLOWER Filed April 25, 1950 FE CL- IN V EN TOR. Mme/s 6 7 :o/v.

ymwm Patented Dec. 23, 1952 UNITED STATES PATENT OFFICE 3 Claims. 7 (01. 28-715) The present invention relates to blowing means for the pneumatic deposition of fibers, filaments, strands, yarn, and the like. By pneumatic I mean to include all fluids and particularly gases such as air. The invention will be disclosed in connection with the latter. Further, hereafter in the specification and claims, the term strand will be taken generically to include all such products, for example, as those just mentioned, whether twisted or untwisted, staple or continuous, or of one or many ends.

While blowers are known in the art, I am aware of none that has the advantageous features of the present invention, particularly in combination.

One object of the invention is to provide blowing means operable at a greatly reduced air pressure without a sacrifice of capacity of the blowing means or in the rate of processing the strands.

Another object is to provide blowing means that quickly dissipates the force of the air so that the fiber or strand deposition may be more readily controlled.

' A further object is to provide blowing means that is very simple in construction, highly efficient, and unusually minute in size so that it is readily used in conjunction with other processes with a minimum of inconvenience or interference.

More specific objects and advantages are apparent from the following description which merely discloses and illustrates the invention and is not intended to limit the claims.

The invention is blowing means comprising a body having a bore therethrough and means lateral to the bore for the admission of fluids.

V In the drawings:

Figure 1 is a vertical, longitudinal cross-section of one form of the present invention;

Figure 2 is a side elevation, partially in section, of apparatus using the present invention to reinforce glass fiber mats or bats; and

Figure 3 is a schematic drawing illustrating use of the present invention to reinforce paper.

Referring to Figure 1, in this form of the invention l represents a blower comprising an elongated body which may be cylindrical, hexagonal or other polygonal, cross-sectional configuration. A central bore or tube ll extends longitudinally and at l2 has its smallest diameter so "as to form a throat or restriction at that point. A recess or cavity I3 on one side of the blower communicates with the bore through a small tube I4. The recess is threaded to engage a tube fitting l5 which thereby couples tubing IE to the blower ID. The fitting l5 has a slot I! for the passage of air orother fluids. The entrance [8 andexit [9 t theblowerare preferably flared.

iii

In operation, a strand is threaded through the bore II and air for example is admitted under pressure from the tubing I6 through the lance tube l4. Thereafter the force of the expanding air and resulting turbulence pulls the strand through the blower and continues to support the strand until the force becomes dissipated at some point beyond the exit of the blower.

I have found that if a'bore having a restriction at the entrance end is used instead or a straightbore, the blower may be operated at an ap leciably lower air pressure with a resulting turbulence within the blower that is usually met only when much higher pressures are used. For example, blowers of the present invention are very satisfactorily operable at pressures of only 20 to 30 pounds per square inch whereas customarily pressures of to pounds per square inch are used to obtain the same turbulence and process the same amount of strand. Also, there is an increase in efiiciency of operation with the present blower without a sacrifice in the rate at which the strands are processed.

These advantages are thought to be due in part to the increase in velocity imparted to the air passing through the entrance [8 by the restriction I2 in accordance with Bernoullis theorem. This effect alone can be realized by directing the air into the blower through the same entrance as that used by the strand. However, in the present invention, this effect is magnified by positioning the entrance of the lance tube M to the bore immediately after the restriction so that as the air speeds through the tube l4 and out the blower, a partial vacuum is formed within the bore between the restriction l2 and the point where the tube l4 reaches the bore. Thus the air thereby induced through the entrance I8 acts in conjunction with the supplied air and is thought to result in a decrease in the pressure normally required for the latter. For best results the sides of the restriction should gradually slope outwardly until the major diameter of the bore is reached so as toform a venturi-like construction. It has als'o'been found advisable to maintain the diameter of the bore substantially constant after the restriction [2 in order not to create downstream disturbances that destroy the pattern of flow.

The angle of lance tube [4 with the boreis critical to the operation of the blower. If the angle is less than about 10 degrees or more than about 60 degrees, the blower is substantially inoperable. The desired angle is about 30 degrees to 50 degrees since at this angle the air jet appears to grasp more readily the strandsand more 3 forcibly pull them through the blower. The preferred angle is about 35 to 45 degrees because for one thing more strand is processed for the unit amount of air used at such an angle.

I have further found that the force of the expanding air is quickly dissipated if the exit of the blower is flared. A quick dissipation is desirable because the overall operation can then be confined to a relatively mall area and the deposition of the strand more easily controlled. The latter desideratum is particularly important when the blower is used to form mats as hereafter described because then it is most essential that the strands fall freely in controlled, even, overlapping loops that are uniformly distributed to provide tensile strength in all directions parallel to the face of the mat.

While not as critical as at the exit, the operation of the blower is improved if the entrance is also flared. This not only allows the blower to be easily threaded but minimizes frictional resistance to the flow of the strand and induced air through the bore II. In both cases it is preferred to use a flare having a curved surface. This construction further minimizes frictional resistance to the flow and prevents excessive turbulence. Accordingly, there are less disturbances to the desired pattern of flow. All these advantages are best realized when the curved surface is one having approximately a 90 degree arc. For instance, in this case, the force is found to be dissipated within 12 to 14 inches from the end of the blower.

Without meaning to limit the invention, a highly satisfactory embodiment comprises a blower only two inches long and a half inch Wide having a bore inch in diameter. The diameter of the bore at the restriction is '70 mils and that of the lance tube 39 mils. This blower operating at a pressure of only 20 to 30 pounds per square inch handles a glass strand comprising 102 filaments and averaging from approximately 15,000 to 45,000 yards per pound.

While the present blower is easily adaptable for the processing of various kinds of strands such as wool, cotton, rayon, Nylon (polyameric amides), Vinyon (copolymer of vinyl chloride and vinyl acetate), and the like, it'is especially useful in the handling of glass strands. Because of their round, smooth, even surfaces, glass filaments do not catch one upon the other, particularly as compared to wool fibers. Consequently, it is necessary to apply a size or hinder such as a thermosetting resin to the filaments to adhere one to the other and realize some degree of strand integrity. When such strands'are processed through conventional high pressure blowers, they are subjected to a drastic pounding from the shock waves produced by the turbulence. As a result, the size or binder is apt to be jarred loose and broken away from the strands thereby greatly reducing or even destroying the strand integrity. This is especially true when the size or binder is a thermosetting resin, as described, since they tend to be so brittle. In contrast, glass strands are not subjected to such a severe pounding in the low pressure operated blowers of this invention and consequently there is not the danger of destroying strand integrity.

The blower of the present invention may be used in a variety of applications although it is chiefly employed to supply reinforcing strands. Examples of this use are shown in Figures 2 and 3. A

Figure 2 illustrates a conventional method of forming glass fiber mats and bats wherein 20 represents a feeder from which a plurality of streams of molten glass 21 continuously issue. The streams are caught in gaseous blasts issuing from the blower 2'2 and are forcibly drawn and attenuated into fine fibers 23 which pass through the hood 2% and are deposited on a moving conveyor 25. The collection of the fibers may be aided by a suction duct 26 which extracts the blasts of the blower from the hood and attracts the fibers to the conveyor. Thereafter the fiber collection 21 may be sprayed with a binder such as phenol formaldehyde as at 28 which is then polymerized, for example by heat, to impart rigidity and mass integrity to the fibrous product.

It is sometimes desired to reinforce such products by the addition of continuous strands. To this end, the hood 24 has an offset 29 provided with an opening to receive the discharge of a blower 30 representing an embodiment of the present invention. A strand is drawn to the blower from a package 3| and intermixedwith the blower fibers 23 as shown.

Figure 3 illustrates how the present blower may be used to produce reinforced paper. A sheet of paper 32 is advanced from a roll 33 below the instant blower 34. The sheet is preferably coated straight line before it. The distance is very short.

since the expanding force is quickly dissipated. After the force is spent, the unsupported strand is free to fall and double back and forth on itself on the sheet 32 in neat loops or spirals which overlap each other to form an attractive overall pattern. An additional sheet 36, which may be coated or uncoated with an adhesive, is then laid over the mat of fiber loops and the entire assembly passed between heated rolls 3'! and. 38 to compress and seal the three members together in a sandwich construction. Thereafter the reinforced paper may be collected as a roll 39.

Various modifications are possible in such a method. For example, a plurality of blowers 34 may be used in juxtaposed position. Further, they may be oscillated transversely to the direction of travel of the sheet 32 to obtain a more uniform distribution of the loops.

Or instead of reinforcing paper, the blowers may be used just to produce the fibrous mats themselves by catching the loops directly on a moving conveyor, spraying them with a binder and then processing in a manner analogous to that described for the fiber mat or bat-210i Figure 2. Such mats may be used to reinforce plastics, coated fabrics, and the like.

Various other modifications and changes may be made in the invention within the spirit and scope of the appended claims to meet diverse requirements.

I claim:

1. A blower for the deposition of a strand including a pencil-like body having a'longitudinal bore slightly greater in diameter than the diameter of the strand, said bore having a transverse circumferential restriction followed by a gradual widening of the bore to the original diameten-a single tubular opening communicating with the borefrom one side on the downstream-side of the restriction and intersecting the aXis of thebore at an angle of 10 to 60 degrees.

2; A small blower forthe pneumatic deposition of a strand including a rod-like body having a longitudinal bore slightly greater in diameter than the diameter of the strand and a flared exit, said bore being provided with a transverse circumferential restriction near the entrance followed by a gradual widening of the bore to the original diameter, a lateral recess in the body having a single tube communicating with the bore at the point on the downstream side of the restriction where the original bore diameter is first reached and intersecting the axis of the bore in the direction of strand travel at an angle approximating 30 to 50 degrees.

3. A small, compact blower for the pneumatic deposition of a glass strand including a rod-like body having a narrow longitudinal bore and a curved, flared exit, said bore being slightly greater in diameter than the diameter of the strand whereby a relatively closely fitting relation between the body and the strand is obtained, a transverse circumferential restriction at the entrance of the bore followed by a gradual radial widening of the bore to a larger diameter which 20 thereafter remains constant up to the flared exit, a recess in the body laterally disposed to the bore and adaptable to engage gas supplying means, a

MORRIS C. ANDERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,302,790 Modigliani Nov. 24, 1942 2,392,882 Roberts Jan. 15, 1946 2,446,097 Nelson July 27, 1948 FOREIGN PATENTS Number Country Date 512,240 Great Britain Aug. 31, 1939 553,896 Great Britain June 9, 1943 942,822 France Feb. 18, 1949

Images