US2715384A

US2715384A - Ultrasonic device

Info

Publication number: US2715384A
Application number: US348183A
Authority: US
Inventors: Carl L Meng
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-04-13
Filing date: 1953-04-13
Publication date: 1955-08-16
Anticipated expiration: 1972-08-16

Description

Aug. 16, 1955 Filed April 15, 1953 c. L. MENG ULTRASONIC DEVICE 2 Sheets-Sheet l IN VEN TOR.

CARL. l MENG BY V"- ATTORNEYS Aug. 16, 1955 Filed April 13, 1953 c. L. MENG ULTRASONIC DEVICE 2 Sheets-Sheet 2 I INVENTOR.

CARL L MENG [MGM ATTORNEYS United States Patent ULTRASONIC DEVICE Carl L. Meng, Phoenix, Ariz.

Application April 13, 1953, Serial No. 348,183

4 Claims. (Cl. 116137) An object of my invention is to provide an ultrasonic device which is an improvement over the device shown in my copending application, Serial No. 211,148, filed February 15, 1951. In the present case, the nozzles for the compressed air are spaced apart and extend from a ring-shaped manifold that has a circumference substantially equal to the circumference of the circular row of radially-extending fins that are arranged around the periphery of the rotor. In order to obtain the highest possible frequency for the air stream, there must be the greatest possible number of fins on the rotor. The sac and shape of the fins will be governed largely by the facilities for cutting them into or attaching them to the rim of the disc. The factor of erosion by the compressed air jets will also affect their design.

The device which is described herein is for the purpose of generating ultrasonic waves for as many practical uses as is possible. The method used to produce the waves is the interruption of jets of compressed an by fins on the periphery of a disc. It is planned to use a (1180 having a diameter of about five feet four inches. The disc will be rotated at about 3600 revolutions per minute and it will have a peripheral speed of about 1000 feet per second. The diameter and rotational speed of the disc are both limited, because of the tendency to rupture under stresses due to centrifugal force.

The intensity or energy of the wave is derived from the pulse of air which travels past the interrupting fin. The uses of ultrasonic treatment which are considered advantageous, generally require high intensity. Therefore it is desirable that the largest possible volume of air shall pass through the opening between two adjacent fins during the very slight interval between interruptions. This requires that the width of the fins be as much smaller than the width of the space between adjacent fins as design will permit. A greater volume of air passes through the passageways with a production of a greater wave energy.

Practical considerations fix the allowable pressure of the compressed air or gas which is delivered to the orifice of the nozzle. Manufacturers of compressed air machinery recommend the use of a maximum pressure not to exceed 125 pounds per square inch. An orifice diameter of inch for the nozzle will deliver 7.9 cubic feet per minute under this pressure and the velocity of the corresponding jet of air will be approximately 738 feet per second. Since the maximum air pressure, and therefore jet velocity is limited, the peripheral speed, and the dimensions of the fins and passageways between the fins are likewise limited. The fins do not completely obstruct the direct flow of the air stream.

Other objects and advantages will appear in the following specification, and the novel features of the device will be particularly pointed out in the appended claims.

My invention is illustrated in the accompanying drawing forming a part of this application, in which:

Figure l is a top plan view of the device;

Figure 2 is a transverse section taken along the line II-II of Figure 1; 1

Figure 3 is an enlarged view of the dot dash circled portion III in Figure 2;

Figure 4 is a vertical section taken along the line IV-IV of Figure 3;

Figure 5 is a view similar to Figure 3, but of a modified form of the device;

Figure 6 is a vertical section taken along the line VIVI of Figure 5 Figure 7 is a view similar to Figure 3, but of another modified form of the invention; and

Figure 8 is a top plan view of Figure 7.

While I have shown only the preferred form of my invention, it should be understood that various changes or modifications may be made within the scope of the appended claims without departing from the spirit and scope of the invention.

In carrying out my invention, I provide a frame indicated generally at A for supporting a motor B. The frame in turn is placed abouve a trough C that has two

sides

1 and 2 and a bottom 3. A liquid 4 or other substance, that is to be treated by the ultrasonic waves, is flowed through the trough C. I do not wish to be confined to any particular use for the ultrasonic waves, since my invention is to provide an ultrasonic device whose waves can be used for any desired purpose.

The motor B has a depending shaft 5 and this shaft supports a disc D. The disc is made of material having a high tensile strength and the diameter of the disc is approximately 5 4". The thickness of the disc will vary, decreasing from the center toward the periphery. At the periphery of the disc I provide a plurality of radially extending fins E and in a disc of the size mentioned, there are approximately 1700 fins arranged around the disc periphery.

The fins may be of various shapes and in Figures 3 and 4, I show the fins E on a larger scale. Figure 4 illustrates an end view of the fins and it will be seen that they are wedge-shaped in cross section with the wider surface facing upwardly. The fins are spaced from each other to form tapered air passageways which are as wide as possible with respect to the width of the fins E so that the flow of the air stream through the passageways will not be obstructed to too great an extent. The narrower part of each passageway is at the point where the air enters the passageway.

Referring to Figures 1 and 2, it will be seen that I provide a ring-shaped conduit P which has an air pipe 7 communicating therewith. The air pipe is in communication with a source of compressed air, not shown, and therefore the ring-shaped conduit F will be filled with compressed air under a desired pressure, such as 125 pounds per square inch.

The ring-shaped conduit has about thirty nozzles G depending therefrom and spaced equal distances one from another, as illustrated in Figures 1 and 2. I do not wish to be limited to any exact number of nozzles. The ring-shaped conduit is placed directly above the circular row of fins E so that the depending nozzles G will have their orifices direct their air streams downwardly against the fins, and the air passageways 6, the air streams being interrupted as the fins pass thereby, and the air streams flowing through the air passageways 6 formed between adjacent fins, when these passageways momentarily register with the air streams. Figure 4 illustrates one of the nozzles G on a larger scale and the outlet end of this nozzle is placed above the circular row of fins E so as to give a clearance of approximately .060".

The disc is preferably rotated at a speed of 3600 revolutions per minute and therefore the peripheral speed of the disc will be about one thousand feet per second.

ice

' substance, in the trough C.

The opening in each nozzle is about one-sixteenth of an inch, and with an air pressure of 125 pounds per square inch, a volume of air amounting to 7.9 cubic feet per minute will be delivered from each nozzle. The velocity of the air stream issuing from each nozzle will be approximately 738 feet per second. Each of the thirty air streams is interrupted by the rapidly moving fins E and since there are 1700 fins on the periphery of the disc, the waves created by the rotating disc and the air interrupting fins will be in the ultrasonic zone 'of 100,000 or more waves per second. When 1700 fins are mounted on a disc rotating 3600 revolutions per minute, the air stream from one nozzle will be interrupted 102,000 times per second. With thirty nozzles thecombined interruptions will be 3,060,000 per second.

These ultrasonic waves can be directed against any object desired, and only by way of one example, I have shown these waves directed against the fluid 4, or other It is obvious that the waves can be used for any purpose desired.

In Figure 2 I show the circular ring F supported by rods 8, or other suitable supporting means, and these rods are suspended from the under side of the frame A. I do not wish to be confined to any particular circular ring supporting means, nor to any particular type of frame A that supports the electric motor B.

' The width of the air passageways 6 is made as large as possible with respect to the width of the Wedge-shaped fins E. I found that a greater volume of air passes throughthe passageways and produces a greater wave energy when this is true. The shapes of the fins may be varied and I have shown two modified forms of fins in Figures to 8, inclusive.

In Figures 5 and 6, I show the disc D1 provided with 'a plurality of cylindrical shaped fins E1. There are preferably 1700 of these rod-shaped fins placed around the periphery of the disc D1 and extending radially therefrom. Each fin is preferably .040" in diameter and the space between two adjacent fins is prefereably .080". The fins or rods E1 will interrupt the stream of air from the nozzle G in the same manner as the fins E. The passageway in the nozzle G has a diameter of .080.

Another modified form of fin is illustrated in Figures 7 and 8. Here the disc D2 carries a thin ring-shaped member 9 at its outer edge. The ring-shaped member is secured to the disc by a ring-shaped support 10 and rivets 11 or other suitable fastening means secures the support to the disc.

In Figure 8, I show the ring-shaped member 9 provided with a plurality of fins E2 on its outer edge that are in the shape of saw teeth. The air passages between the teeth E2 are V-shaped in plan view. Air will flow from the nozzles G and the air streams will be interrupted by the saw shaped fins E2 as the latter are rapidly moved past the air streams. The ring 9 in reality provides a thin serrated projection for the outer edge of the disc D2.

The uses for which this ultrasonic device can be used for are many. It can be used for the sterilization of liquids such as water, milk and other liquid foods. The medium to be sterilized may be placed in a container and disposed directly under the disc D, rather than flowed through the trough C. To obtain the best results, the container may be of a hollow cylindrical shape inasmuch as the waves will form a cylindrical curtain below the disc.

The temperature of the medium may be controlled by coils, not shown, placed in the wall of the container. In order to reduce losses in the wave energy due to reflection from the liquid surface, a floating metal or plastic membrane may be placed on the surface of the medium being treated. If the upper surface of this membrane is made rough, there will be less energy reflected away.

Homogenization and emulsion may be accomplished in the same Way as sterilization. It is possible to give therapeutical treatments with the device, and this can be accomplished by placing the unit over a table designed for the purpose and upon which a patient is placed. The purification of air, and smoke treatment may be undertaken by enclosing the unit in a duct through which the air or smoke passes.

The rotatable disc and air jet arrangement is based on the principle of Savarts wheel. He used a toothed wheel somewhat like a circular saw to study the pitch of musical tones. A card was held against the teeth and the pitch varied as the speed of rotation was changed. The device was used only for the sonic range. In my device, the jet of air replaces the card and the fins replace the teeth. The vibration of the card is replaced by the air pulsations and the number of fins and the speed of the disc are such as to create ultrasonic waves.

My device has a marked advantage over the siren type of Wave generator which likewise uses a method of air blast with an interrupting means to break up the blast into air waves. In the siren device, the ring of openings in the rotating plate greatly weakens the structure of the plate at the very place it needs great strength. The circular row of openings form a ring-shaped portion beyond the openings that is connected to the plate only by the small web-like portions lying between adjacent openings in the row. The mass of that part of the plate lying outside of the ring of openings or holes, exerts the greatest unit of centrifugal force of the entire volume of the plate during its rotation. This stress is entirely carried by the thin webs of metal between adjacent holes and as the speed increases, these Webs tend to rupture and the portion of the plate lying beyond the circular ring of holes is likely to break loose.

Furthermore, when such a siren type of wave generator is used and the plate with the circular row of openings is rotated rapidly with respect to a stationary disc having a similar circular row of openings that register with the first row, the time element when an opening in the plate registers with an opening in the stationary disc or ring is so fleeting that it is practically impossible to force any air through the registering openings. In one siren device, it has been stated that the frequency with which the perforations or openings in the rotating member register with the openings in the stationary member is approximately five hundred thousand per second when the peripheral velocity of the rotor is approximately three thousand feet per second.

The piezoelectric generator can attain a much higher frequency than those devices which use gas or air generated Waves, but the energy output is limited. Piezoelectric effect is an action occurring in certain substances, notably quartz crystals, which when acting as conductors of alternating current, experience alternating tensile and compressive stresses which affect their volumes. A frequency of 100,000 cycles per second can be safely attained with my device. Ultrasonic waves have frequencies above the sonic range, i. e., 20,000 to 500,000,000 vibrations per second (the highest reported yet attained).

Sonoration is a term used by certain investigators and technicians, and refers to subjecting certain media to ultrasonic Wave energy for a specific purpose, such as emulsion, destruction of bacteria, or homogenization.

I claim:

1. In a device for generating ultrasonic waves, a frame, a rotor rotatably supported on said frame, said rotor being rotatable about a central axis and having a circular periphery with a plurality of fins arranged around said periphery of said rotor concentric with the center of said rotor and connected to said rotor and movable therewith, said fins being spaced from each other to define unobstructed air passageways that parallel the rotor axis and also open radially outwardly of said rotor, a ring shaped air conduit having substantially the same diameter as the plurality of concentric fins, rods connected to said frame and supporting said conduit concentric of said axis and adjacent one end of said passageways, a plurality of air nozzles connected to said conduit and having discharge outlets directed in alignment with the said central axis of said rotor and in longitudinal alignment with said passageways adjacent one end thereof, said outlets and said fins being equally radially distant from said central axis and said outlets being axially spaced along said central axis with respect to said passageways, means for rotating said rotor supported on said frame and connected to said rotor, said last named means serving to turn said rotor about said central axis to move said fins laterally across the paths of air emitted from said nozzles and to alternately bring said air passageways into and out of alignment with said paths of air emitted from said nozzles, said passageways all being simultaneously in or out of alignment with said paths of air, means for delivering air under pressure into said conduit for discharge through said nozzles, said means for rotating said rotor being adapted to rotate said rotor at a speed sufficient to produce ultrasonic waves in the air stream delivered from said nozzle, the air stream pulsating at ultrasonic pulsations forming a cylindrical curtain below the rotor that is free to move against the air and against the matter to be treated without any further guidance for the air flow.

2. The combination as set forth in claim 1, in which the nozzles are spaced equal distances from each other, and in which the fins extend radially from the periphery of the rotor and are spaced equal distances apart.

3. The combination as set forth in claim 1, and in which the fins extend radially from the rotor periphery and are cylindrical in shape.

4. The combination as set forth in claim 1, and in which the fins are formed as a series of saw-toothed projections on a ring secured to the rotor, with the projections extending beyond the periphery of the rotor.

References Cited in the file of this patent UNITED STATES PATENTS 2,528,026 Allen Oct. 31, 1950 2,562,545 Gogolick July 31, 1951 2,570,081 Szczeniowski Oct. 2, 1951