U.S. patent number 3,635,762 [Application Number 05/073,994] was granted by the patent office on 1972-01-18 for ultrasonic cleaning of a web of film.
This patent grant is currently assigned to Eastman Kodak Company. Invention is credited to Jerry Carmen, Howard F. Ott.
United States Patent |
3,635,762 |
Ott , et al. |
January 18, 1972 |
ULTRASONIC CLEANING OF A WEB OF FILM
Abstract
Dirt particles are cleaned from a web of flexible material, such
as photographic film or paper, by applying ultrasonic vibrations to
a web in a direction transversely of the web while applying a
solvent liquid to the web. The liquid can be applied by immersion
of the web and ultrasonically vibrating apparatus in a pool, or by
spraying the liquid onto the web as it passes over the apparatus in
air. Vibrations are imparted by passing the web between a pair of
shoulders defining a circular channel for the films.
Inventors: |
Ott; Howard F. (Victor, NY),
Carmen; Jerry (Spencerport, NY) |
Assignee: |
Eastman Kodak Company
(Rochester, NY)
|
Family
ID: |
22117060 |
Appl.
No.: |
05/073,994 |
Filed: |
September 21, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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879680 |
Nov 25, 1969 |
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Current U.S.
Class: |
134/1; 15/94;
134/9; 134/184; 15/100; 134/64R; 355/30 |
Current CPC
Class: |
B08B
7/028 (20130101); B08B 3/123 (20130101) |
Current International
Class: |
B08B
3/12 (20060101); B08b 007/02 () |
Field of
Search: |
;134/1,6,9,15-17,64,122,184 ;15/94,100 ;355/15,30 ;68/3SS |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Wolk; Morris O.
Assistant Examiner: Zatarga; Joseph T.
Parent Case Text
This application is a continuation-in-part of our application, Ser.
No. 879,680 filed Nov. 25, 1969.
Claims
We claim:
1. A method of cleaning dirt particles from a web of flexible
material comprising moving said web in a direction lengthwise
thereof, contacting at least one edge of said moving web with a
solid ultrasonically vibrating abutment, and ultrasonically
vibrating said contacting abutment in a direction transversely
across the width of said moving web while simultaneously applying a
volatile liquid solvent to said moving web at the location of
contact with the ultrasonically vibrating abutment.
2. A method in accordance with claim 1 wherein said liquid is
applied by immersing said web in a pool thereof.
3. A method in accordance with claim 1 wherein said liquid is
applied by spraying onto at least one surface of said web.
4. A method in accordance with claim 1 wherein said liquid is
applied by spraying onto both surfaces of said web.
5. A method in accordance with claim 1 wherein said liquid is
applied by rotating a liquid-laden roller in contact with a surface
of said web.
6. Apparatus for cleaning dirt particles from a web of flexible
material by applying ultrasonic vibrations to said web in a
direction transversely across the width thereof comprising, in
combination: a longitudinally extending ultrasonically vibratable
device having abutment means extending transversely from a side
surface thereof; mechanism for advancing a web to be cleaned in a
lengthwise direction transversely across said device with at least
one edge of said web contacting said abutment means; means for
ultrasonically vibrating said device in a direction longitudinally
thereof to impart ultrasonic vibrations to said advancing web
through said contacting abutment means in a direction transversely
across the width of said advancing web; and, means for
simultaneously applying a volatile liquid solvent to said advancing
web at the location of contact with said ultrasonically vibrating
abutment means.
7. Apparatus in accordance with claim 6 wherein said liquid
applying means is a tank containing a pool of said liquid, and
wherein said abutment means is immersed in said pool whereby said
web is immersed in said liquid.
8. Apparatus in accordance with claim 6 wherein said liquid
applying means comprises means for spraying said liquid on said
web.
9. Apparatus in accordance with claim 6 wherein said liquid
applying means comprises a roller engaging a surface of said web,
and means for conveying liquid to said roller and thence to said
web.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel method of and apparatus
for ultrasonically cleaning dirt from a web of flexible material
such as photographic film or paper.
During the manufacture of webs of photographic film or paper, it is
important that dirt particles be prevented from accumulating on a
web because such particles will adversely affect the quality when
photographic emulsions are coated over such particles. Moreover, if
dirt particles should accumulate on the top of the finished web
(before or after exposure and development) the quality of the
photographs may be impaired, and the film may be scratched as it
passes through a projector.
Dirt particles can accumulate from the ambient atmosphere, or can
result from slitting and punching operations normally employed
during the manufacture of photographic film and paper.
2. The prior Art
In the past, photographic film has been cleaned by immersing it in
a liquid bath, which is then subjected to ultrasonic vibrations,
cleaning being accomplished by cavitation of the liquid. (See U.S.
Pat. Nos. 2,967,119 and 3,422,479.) This requires the introduction
of bulky equipment into the production line for the cleaning
operation. Moreover, cavitation does not do as thorough a job as
desired.
SUMMARY OF THE INVENTION
In our copending application, Ser. No. 879,680 we have described
the ultrasonic dry cleaning of a web by passing it in a dry
condition over an ultrasonic horn having shoulders which impart
vibrations to the edges of the web. This is especially advantageous
for cleaning webs of materials which may be harmed by volatile
liquid solvents ordinarily used for cleaning baths.
We have now found that the principles of our copending application
can be employed to good advantage by applying a volatile liquid to
a web during ultrasonic vibration thereof, where the web material
will not be harmed by contact with the liquid. Moreover, the
efficiency of the operation is improved by increasing the mass of
dirt particles by wetting them so that they will be jarred off the
web. Additionally, the particles shaken off are readily transported
away from the web in the washing liquid.
The liquid can be applied, advantageously, by dipping the web below
the surface of a pool, or by spraying the liquid on one or both
surfaces of the web in air, or by wiping a liquid-laden roller
against one or both web surfaces in air.
THE DRAWING
FIG. 1 is an end view, partly broken away, showing apparatus for
transporting a web through a pool of liquid while ultrasonically
vibrating the web;
FIG. 2 is a side elevational view, partly in section, of the
apparatus as seen from the right in FIG. 1;
FIGS. 3, 4 and 5 are side elevational views, partly in vertical
section, of three modified forms of apparatus wherein a web is
transported through a pool of liquid.
FIGS. 6 and 7 are end views of two modified forms of apparatus
wherein liquid is sprayed against a web; and
FIG. 8 is an end view, partly in section, of still another
modification for applying liquid to a web by a rotating roller.
THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, there is shown a nonrotating ultrasonic
horn 11 having two oppositely tapered annular flanges 13 and 15
projecting laterally therefrom at positions spaced longitudinally
from each other, thus forming a pair of opposed circular shoulders
or abutments which define a circular channel C of generally
cylindrical or slightly frustoconical shape therebetween.
The horn is operatively connected to an ultrasonic transducer 17
which may be of the electrostrictive (piezoelectric) or
magnetostrictive types, such as have been described in many United
States patents, for example in U.S. Pat. Nos. 2,748,298 (Calosi et
al.--magnetostrictive); 3,022,814 (Bodine--both types); and
3,328,610 (Jacke et al.--piezoelectric). The major direction of
vibration should be along the longitudinal axis of the horn, as
shown by the double pointed arrow. Of course, the transducer 17
should be clamped in a suitable holding device 19.
The end of horn 11 is of much greater diameter than the main body
of the horn, and dips down into a pool 21 of cleaning liquid in a
vessel 23. This large end permits a substantial length of web of
large area to dip into pool 21 during vibration thereof.
In operation, a web 25 of flexible material, shown as moving
picture film having perforations along one side, is transported
from a source to the ultrasonic horn. Film 25 is bent around the
horn within channel C and is taken up on a motor driven spool 27.
As the film moves continuously through channel C, the transducer 17
is energized to impart back-and-forth vibrations to the flanges 13
and 15 which engage both edges of the film and impart the
vibrations to the film in the film plane, thus shaking off from
both top and bottom surfaces any dirt particles present.
Among suitable liquids for the pool 21 are methyl chloroform,
freons, trichloroethylene, trichloromonofluoromethane,
perchloroethylene, carbon tetrachloride, dichlorodifluoromethane,
dichloromonofluoromethane, monochlorotrifluoroethane, and
dichlorotetrafluoroethane.
The success of our method results from so rapidly accelerating the
web relative to the dirt particles (which have extremely small
inertia) that the particles are torn loose from the web. In one
example, an ultrasonic horn as shown was operated at 20 kHz. with a
longitudinal excursion of 0.001 inch, providing a web acceleration
transversely approximately 40,000 times gravity. Thus the forces
exerted on dirt particles relative to the web were approximately
40,000 times the weights of the particles. This, coupled with the
fact that the force is reversing its direction 20,000 times per
second, explains the ability of our apparatus to rip dirt particles
loose from the web.
In the embodiment of FIG. 3, a nonrotating ultrasonic horn 31
having two flanges is connected to a transducer 33 which projects
through an aperture 34 in a sidewall of a container 35 and is
sealed by a circular mounting plate 37 pressing against a gasket
39. Horn 31 is of smaller diameter than that of FIG. 1, and is
fully immersed in the liquid 41. Mounting plate 37 is clamped
between parts of the transducer by a central bolt 41 which bears
against the outer end of the transducer and is threaded into the
front or horn end of the device.
In FIG. 4 vibrations are imparted to the web by a flexing-type
nonrotating piezoelectric crystal element 43 consisting of two
face-shear plates or two transverse-expander plates secured
together face-to-face in such a manner that a voltage applied to
the electrodes in a known way causes the plates to deform in
opposite directions. Suitable elements are sold under the trade
name "Bimorph" by the Clevite Corporation Piezoelectric Division,
Cleveland, Ohio. Element 43 is mounted on a rigid support 45 and
can be revolved thereon to present new guide surfaces as the old
are worn. Only the lower portion of the element is immersed in
liquid.
FIG. 5 is similar to FIG. 4 except that the element 43 is fully
immersed in liquid.
In FIG. 6 a web 45 is passed over a horn 47 like that of FIG. 3,
but instead of being immersed in a pool of liquid the horn and web
are in the ambient atmosphere such as air, and the under surface of
the web is sprayed with a stream of solvent liquid from a nozzle
49.
FIG. 7 is like FIG. 6, but two liquid sprayers are applied, one to
each surface of the web from nozzles 49 and 51.
In FIG. 8 the web 45 is wiped on its undersurface with a liquid
laden roller 53 having a nap, which dips down into a pool 55 of
liquid. Roller 53 can be motor driven, or can be an idler roller
which is actuated by friction with the web.
In all the devices described above it is to be understood that the
web can be sprayed or flushed with clean solvent after the
vibration treatment. Also liquid can be removed from the web in any
desired way prior to windup, as is well known.
Among the advantages of the various forms of apparatus described
above are:
a. the shear forces on the dirt particles are many times more
effective in removing surface dirt than the forces normal to the
web surface generated in cavitation.
b. the energy is far more efficiently used in directly vibrating
the web transversely than in vibrating the liquid.
c. effective cleaning is obtainable with a small portable unit.
d. the nonrotating flanged devices can be revolved periodically to
present new unworn surfaces to the web.
The invention has been described in detail with particular
reference to preferred embodiments thereof, but it will be
understood that variations and modifications can be effected within
the spirit and scope of the invention.
* * * * *