US3080014A

US3080014A - Suppression of objectionable noise in rotating machinery

Info

Publication number: US3080014A
Application number: US858279A
Authority: US
Inventors: Carl B Dahl
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1959-12-08
Filing date: 1959-12-08
Publication date: 1963-03-05
Anticipated expiration: 1980-03-05

Description

United States 3,080,014 SUPPRESSION OF OBJECTIONABLE NOISE IN ROTATING MACHENERY Carl B. Dahl, Rockton, Ill., assignor to Beioit Iron Works,

l Beloit, Wis., a corporation of Wisconsin Filed Dec. 8, 1959. Ser. No. 858,279 7 Claims. (Cl. 181-33) 'or surfaces which pass another member such as a mating roll, in close proximity thereto producing objectionable noise. The iirst roll rotates at a given speed at or above the critical speed at which noise is generated, and hasits grooves at substantially uniform spacing generating noise inthe zone of proximity to the other member. The noisecommences at the critical speed and becomes louder as the speed is increased. The grooves are normally parallel to the axis of the roll. The present improvement positions the grooves at a particular or critical angle so that the objectionable noise is substantially eliminated. This angle is substantially equal to the arctan of the speed of movement of the surface of the roll in feet per minute .divided by 33,600 or one half the speed of sound in feet per minute. The term arctan is used in the usual trigonometric sense indicating the angle whose tangent is the quantity set forth.

Accordingly, an object of the invention is to provide an improved roll structure with grooves in the surface wherein noise generated by the grooves passing in contact or momentary proximity to another member will be substantially eliminated by positioning the grooves at an angle so that each sound wave train originating at the impact or near impact of the groove with thev other member generates a wave train which is displaced by one half wave length or less from the wave train generated by the adjacent groove.

'i Another object of the invention is to provide an improved grooved roll construction for use in machines such as paper Winders with the grooves critically arranged to substantially eliminate objectionable noise generated by the grooves.

"Other objects and advantages will become more apparent with the teaching of the principles of the invention in connection with the disclosure of the preferred embodiments in the speciiication, claims andfdrawings, in which:

FIGURE l is a fragmentary sectional view taken at right angles to the axis of a grooved roll embodying the principles of the present invention;

' FIGURE 2 is a fragmentary plan view of the surface of the roll showing the arrangement of the grooves;

' FIGURE 3 isa fragmentary sectional view showing a grooved roll rotating in close proximity to a iixed member; and

FIGURE 4 is a fragmentary elevational view illustrating the nip of two adjacent rolls with one of the rolls having a herringbone groove configuration thereon.

As shown on the drawings: i

As illustrated in FIGURES l and 2, a portion of a rotating rotor nor roll 10 is shown having an outer surface 11v with grooves or recesses 12 formed therein. The grooves are substantially equally spaced from each other and the roll 1 0 rotates adjacent another member r13 such as a roll with a cylindrical outer surface 14. This arrangement brings the grooves 12 into momentary proxim- The critical angle, as herein used, is defined as thel g 16 with grooves 17 therein.

groove is in proximate relationship to the edge will be.

Y wave train originating in the impact or near impact .of the:

ity to the roll 13 and at rotational speeds above the critical speed of the roll 10, noise will be generated.

In accordance with the present invention the grooves are angled with respect to the axis of the roll at a critical angle which causes the wave train generated between each groove and the roll 13 to be one half a wave length or less away from the Wave train generated at the adjacent groove. This obtains self-cancelling of the noise of each sound wave train originating in the impact or near impact of the groove with the adjacent member 13.

groove angle at which the noise of the roll is cancelled or eliminated.

FIGURE 3 illustrates another form of mechanism wherein a rotor or roll 15 has a cylindrical outer surfacerotates past a fixed member 18 having an edge 19 in close proximity to the roll surface 16 so that a sound wave train is generated as each groove passes the edge 19. For convenience of reference the zone wherein the referred to as the proximity zone.

The proximity zone is substantially at the' nip between the two rolls 10 and 13 of FIGURE 1.

By making the rolls with the grooves set at an angle to the axis, and making or orienting the groove angle at a critical angle or at an angle greater than this critical angle, so that the wave trains are one half wave length or less apart, the noise generated is self-cancelling butthe loss of performance is zero or negligible. Where side thrust or reduced traction, such as in paper rewinder respect to the roll axis and in accordance with the present' principles the angle of the groove, or in other words, of?

the groove axis as indicated by the lines 21for the grooves 12, is measured with respect to the line 20 of the proximity" The angle 0 indicates the angle of the grooves and' is positioned so that the angle is equal to the arctan of the speed of movement of the surface of the roll divided by one half the speed of sound. The grooves are angled -so that sound wave trains from adjacent grooves, such as from the adjacent grooves numbered 12 in FIGURE 2, are spaced substantially one half wave length apart so that the sound wave trains originating from the grooves' at the proximity zone 20 will be self-cancelling. For example, if the speed of surface of movement of the roll,

as may be indicated by the directional arrow 22, is measl'V ured in feet per minute, the arctan is obtained by vdividing by 33,600. v an angle with respect to'the roll axis such that the laxial distance between adjacent grooves is equal to no more than one half a wave length of a sound to be suppressed with the sound being the result of a given surface'speed' of the roll with the grooves `spaced a given `distance apart.

f In further illustration of the principle, the frequency of the principal objectionable noise,

f =g cycles/second where:

S=surface speed in feet per second a=peripheral spacing of recesses in feet.

To obtain self-cancelling of such noise each sound In this instance the roll' In some mechaf In other words the grooves extend at groovel or recess fboundary, is associated with a substan-` tially equal wave length train which is displaced by one half wave length or less. Thus by inclining the grooves which are normally parallel to the axis of the roll, lat a critical particular angle d, relative to the line of'co-ntact where:

A-=the wave length vof the objectionable noise generated by a groove passing an adjacent object. c=speed of sound.

=arctan of surface speed divided lby one half the speed of sound.

Thus for a roll or rotor which has a given surface speed?, the grooves must be oriented at an angle which is at or greater than the critical angle which is equal to the arctan of the surface speed in feet per minute divided by 33,600. The critical angle also may be ter-med as equal to the arctan of the surface speed divided by one half the speed of sound, preferably in the environment or location where the rotor is to be used, as of course is determined 4by the condition of surrounding atmosphere.

It will `be understood that while the angle used is preferably substantially at the critical angle or slightly greater so as to cancel noise and yet not orient the groove at such a sharp angle as to adversely alfect the normal funci tion of the groove, angles greater than the critical angle may -be employed for noise cancellation.

The above principles are equally applicable to machines wherein the member in close proximity' to the roll is at an angle to the roll as aforementioned, and are applicable to other types of machinery and other forms of paper machinery such as the Jordan type rener.

In paper machine winders of the type currently used the Winder speeds require angles, dependent on the predetermined speed, inthe range of 9-13 As; illustrated in FIGURE 4, in some instances the side thrust or reduced traction may become .a problemv due to placing the grooves at an angle. In these instancesy the grooves may be reversed on the two halves of the drum surface' to forml a chevron or herringbone pattern. Asillustrated in FIGUREv 4, a roll 23 meeting another roll 24 has the grooves 2-5 on one half of the roll set at an angle with the angle of the grooves 26 on the other half of the roll.. The grooves are at an equal angle with respect to the roll axis. but meet in a V-joint.

The drawings and specification present a detailed disclosure of the preferred embodiments of the invention, Iand it is to be understood that the invention is not limited to the specific for-ms disclosed, but covers all modifications, chan-ges and alternative constructions and methods falling within the scope of the principles taught by the invention. f'

I claim as my invention: j

1. A sound suppressing means in rotating machinery comprising, a rotary roll having equally spaced grooves in its surface, said grooves extending generally axially but at an angle with respect to the axis, said angle being such that the axial distance between adjacentgrooves is equal to one half a wave length of a sound to be suppressed, saidsound being the result ofV r11-givenk surface speed of the roll with the grooves spaced a given distance apart.

2. A sound suppressing means in rotating machinery in accordance with claim l wherein said grooves are formed -by depressions in a cylindrical surface.

3. A sound suppressing means in rotating machinery comprising, a rotary roll having equally spaced grooves in its surface, said grooves extendi-ng generally axially but at an angle with respect to the axis, said angle being lsuch that the axial distance between adjacent grooves is equal to one half a wave length of a sound to be suppressed, said sound being the result of a given surface -speed of the roll with the grooves spaced a given distance apart, said angle being equal to the arctan of said surface speed in feet per minute divided by 33,6010.

Y4. A sound suppressing means in rotating machinery comprising, a rotary roll having equally spaced grooves in its surface, said grooves extending generally axially but at an angle with respect to the axis, said angle being such that the axial distance between adjacent grooves is equal to one half a wave length of a sound to be suppressed, said sound being the result of a given surface speed lof the roll with the grooves spaced a given distance apart, said angle being equal to the arctan of said surface speed divided by one half the speed of sound. f

5.` A sound suppressing means yin rotating machinery comprising, a rotary roll having equally spaced grooves in its surface, said grooves extending in a herringbone pattern to eliminate side thrust on the roll duri-ng rotation and extending generally axially but at an angle with respect to the axis, .said angle being such that the axial distance 'between adjacent grooves is equal to one half a wave length of a sound to be suppressed, said sound being the -result of a given surface speed of the roll with the grooves spaced a given distance apart.

6. A sound suppressing means in' rotating machinery comprising, a rotary roll having equally spaced grooves Vin its surface, and a stationary surface extending axially of the roll and being in close proximity to the roll surface, said grooves extending generally axially but at an angle with respect to the roll axis, said angle being such that the axialdistance between adjacent grooves is equal to one half a wave length of a sound to be'suppressed, said sound being' the result of a given surface speed of the roll With the grooves spaced a given distance apart.A

7. A sound suppressing means in rotating machinery comprising, a rotary roll having equally spaced grooves in its surface, said grooves extending` generally axially but at an anglel with respect to thel roll axis, said angle being such that the axial distance between adjacent grooves is no larger than one halfawave lengthof the sound to'be suppressed, said sound being the result of a given surface speed of the roll with the grooves spaced a given distance' apart. Y

References Cited in the tile of this patent UNITED STATES PATENTSV 1,946,367 Straight Feb. 6, 1934 1,946,838v Coffin Feb. 13., 1934 1,996,418 Hargraves Apr. 2,1935 1,999,988 Anderson Apr. 30, 1935 2,110,471 Petruchkin Mar. 8, 1938v 2,179,579 Morral et al Nov. 14, 1939v 2,245,109 Lapeyrouse June 10, 1941 2,453,240 Malmros Nov. 9, 1948 2,770,279 Harrison Nov. 13, 1956 2,893,487 Dahl et al. July 7, 1959 FOREIGN PATENTS 801,497 Great Britain Sept. 7, 1958 OTHER REFERENCES C.W.E. Walker; The Poweu River ysuenen R011' Silencer, Noise Control, vol 2,V No. 5, September 1956, pages 39-45 and 58. 1

Claims

1. A SOUND SUPPRESSING MEANS IN ROTATING MACHINERY COMPRISING, A ROTARY ROLL HAVING EQUALLY SPACED GROOVES IN ITS SURFACE, SAID GROOVES EXTENDING GENERALLY AXIALLY BUT AT AN ANGLE WITH RESPECT TO THE AXIS, SAID ANGLE BEING SUCH THAT THE AXIAL DISTANCE BETWEEN ADJACENT GROOVES IS EQUAL TO ONE HALF A WAVE LENGTH OF A SOUND TO BE SUPPRESSED, SAID SOUND BEING THE RESULT OF A GIVEN SURFACE SPEED OF THE ROLL WITH THE GROOVES SPACED A GIVEN DISTANCE APART.