US2559864A

US2559864A - Production of high frequency waves in a liquid medium

Info

Publication number: US2559864A
Application number: US27093A
Authority: US
Inventors: Firth Francis George
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-03-24
Filing date: 1948-05-14
Publication date: 1951-07-10
Anticipated expiration: 1968-07-10

Description

F. G. FIRTH July 10-, 1951 PRODUCTION OF HIGH-FREQUENCY WAVES IN A LIQUID MEDIUM Filed May 14, 1948 a I i i i i i n I l INVENTOR W ATTORNEYS Fumcbi Gen Y @mfiwmafm @WM Patented July 10, 1951 PRODUCTION OF HIGH FREQUENCY WAVES IN A LIQUID MEDIUM Francis George Firth, New York, N. Y.

Application May 14, 1948, Serial No. 27,093 In Australia March 24, 1948 6 Claims. (Cl. 116-137 This invention relates tlxthe production of high frequency waves in a. liquid medium, and has for its object the provision of a novel device or system for setting up within a liquid medium waves or vibrations of high frequency.

In a number of commercial fields the application of intense agitation techniques has proven to be of great value. These fields include amongst others chemical manufacturing, emulsiflcation of fluids, mixing, textile cleaning and sterilization. The amount of energy that can be employed with mechanical mixing under normal conditions is very limited, and the agitation is necessarily localised around the impeller or like agitating element in the treating vessel.

The amount of energy that can be developed in such applications can be increased considerably by suitable techniques that employ frequencies of agitations covering the sound spectrum up to very high frequencies. The range of frequencies might be expected to cover, say, 50 cycles per second to 1 mega-cycle per second. For instance, one may refer to the sound spectrum covering frequencies up to say 15,000 cycles, and the ultrasonic range from 15,000 cycles per second upwards.

The present invention contemplates an hydraulic system or device for transforming the energy of a high velocity fluid jet into an intermittent high frequency form 'capable of performing work, and, as will become apparent hereinafter, a system or device which is practical, relatively simple, safe to use, capable of large power inputs, of high efliciency, and suitable for commercial applications involving liquid, or liquidgaseous phases.

In accordance with the invention I utilize a high-energy, high velocity liquid jet and arrange for a controlled small volume of air or an appropriate gas to be admitted into the liquid jet which is directed against a re-action member capable of vibrating at high frequency. The air or gas, being compressible, introduces the factor of intermittency into the otherwise constant pressure of the liquid jet. The liquid impinging on the member causes it to extend, while the entrained gas permits it to recover. Thus, the combined effect of the jet of liquid and entrained gas is to vibrate the member at high frequency, and the re-action member transmits the high frequency waves to the body of liquid to be treated.

The invention will be more readily understood from the following description, relating to certain typical embodiments, aided by reference to the accompanying diagrammatic drawings. It is, however, to be understood that the following description and the drawings are merely by way of example and that various modifications, refinements and/or additionsas would readily occur to those versed in the art after reading this 2 specification, may be incorporated without departing from the spirit and scope of the invention.

In Figure 1 a driven hydraulic pump l is shown connected at the output side to a pipe 2 that 4 of the pipe 2 is located concentrically with the apex A of a flexible diaphragm 5. The diaphragm may advantageously be of the shape of a right cone with a base 3,31. The diaphragm is connected at its perimeter with, a container vessel 0.

Spaced radially and circumferentially around the apex point A, but below it, are a plurality of holes I in the diaphragm which permit free passage of fluids, gases and solids from the interior of the diaphragm to the container vessel. A relatively small diameter tube 8 is connected to the interior of the pipe 2 at the low pressure point of the Venturi constriction, in much the same manner as a water aspirator, which is a well-known vacuum device, for withdrawing gases or liquids from a' system.

The action of the device of Figure 1 is as follows:

The driven hydraulic pump I is supplied with a liquid through an inlet pipe 9, and the liquid is forced at a high pressure through the outlet pipe 2 past the Venturi constriction 3 to the outlet nozzle 4. The resulting high pressure liquid stream will impinge on the diaphragm 5 at the apex A. The diaphragm is supported rigidly at the base 331, and since it is composed of a suitable flexible material, it will tend to extend itself away from the direction of the force from the jet.

Air is drawn through a throttling valve into the tube 8, and admitted in regulated volume to the liquid flowing through the outlet pipe 2, and will appear as intermittent bubbles of air in the liquid stream. This will cause an effect of intermittency to appear in the force of the liquid jet, and the diaphragm will recover intermittently to a less stressed condition.

Thus, the diaphragm will tend to vibrate at a rate that will be dependent on a number of factors including:

(a) The natural period of vibration of the diaphragm system,

(b) The liquid jet pressure,

(c) The amount of air or gas admitted to the fluid moving system,

(d) The geometry of the system.

In accordance with the invention, these factors are adjusted to cause the diaphragm to vibrate at high frequency, which throughout this specification and the appended claims means a frequency of not less than 50 cycles per second. Any or all of these factors can be changed at will with suitable apparatus and the amount of hydraulic energy that it is possible to dissipate is very large. This dissipation of energy will be partly used in moving the diaphragm ABBi.

Thus, any body of liquid held in the container 6.

above the diaphragm will be subjected to vibrations due to the movement of the diaphragm.

It is to be understood that the foregoing embodiment of the invention is only one method of application. The holes I are unnecessary for the operation of the device, if a sealed oil. container vessel is required. Furthermore, the hydraulic liquid can be recirculated by collecting the liquid after it falls from the inner surface of the diaphragm, and by introducing it through inlet pipe 9.

Instead of air being introduced through the tube 8, other gases may be used, as for example, an inert gas suciras argon, a gas for carbonation of water such as carbon dioxide, or any other desired gas.

If it is required that two materials be intimate- 1y mixed, another side tube may be connected to the Venturi constriction, at a place close to the gas tube 8, in such a way that another liquid, gas or solid can be mixed with the pumped liquid. Such an arrangement might be desirable in a chemical precipitation reaction for example, or in connection with the emuisification or dispersion in a liquid medium.

It is to be clearly understood that the diaphragm itself does not necessarily have to be a flexible element in the moving system. The diaphragm can be rigid and supported at the base 13,131 by a flexible member, such as a ring R (Figure 2) between the base and main rigid support.

According to another modification, the diaphragm may be supported at the base in a rigid fashion by the container 6 which is in itself rigidly supported at the end away from the base, and a flexible section let into it, as for example, a ciroumferentially corrugated zone C (Figure 3) somewhere between the support and the base.

The diaphragm does not necessarily have to be of the shape of a right cone, but can be of other appropriate geometric shapes, or of a planar surface, without departing from the spirit of the invention.

An example of the application of a device as before described to a practical usage may be as follows:

Presently available commercial and domestic machines for washing or cleaning fabrics use methods of agitation of the cleaning fluid of a mechanical nature, so that the fluid is moved through the fabrics by means of a mechanically operated paddle mechanism, or by moving the fabrics through the fluid by a rotating drum. Although such mechanisms are to a certain extent eifective they are in fact of very low efllciency due primarily to the waste of mechanical power which moves both the fluid and fabrics simultaneously.

By placing the fabrics in a vessel such as the container 6 in the aforementioned devices and covering them with a washing or cleaning liquid, the diaphragm ABBl can be caused to move at a high frequency by operating the hydraulic pump and admitting a controlled volume of atmospheric air to the tube 8.

The liquid in the container can be recirculated through the pump and returned to the system through holes in the diaphragm. For this purpose the outlet pipe 2 should be sealed within the base of the diaphragm system, and the air pipe 8 be brought out to a point where air is available.

Thus, the movement of the diaphragm will cause the body of liquid above it to move at a high rate of speed through the fabrics, causing a cleaning action without the abrasion to the fabrics that is inevitable with a conventional washing machine. The efliciency of the process is also enhanced by the higher circulating frequencies provided, and by better power conversion.

I claim:

1. A device for producing high frequency vibrations in a liquid medium comprising a container for the medium, a reaction member capable of vibrating at high frequency positioned within the container, means for directing against said reaction member a high velocity jet of liquid, and means for introducing a gas into said liquid jet.

2. A device for producing high frequency vibrations in a liquid medium comprising a container for the medium, a reaction member capable of vibrating at high frequency positioned within the container, and means for vibrating said reaction member at high frequency by directing against it a high velocity jet of liquid and compressible gas.

3. A device for producing high frequency vibrations in a liquid medium comprising a container for the medium, a reaction member capable of vibration positioned within the container, means for directing a high velocity liquid jet against one side of said member, and means for introducing intermittent bubbles of gas into the liquid jet whereby the reaction member is caused to vibrate at high frequency as the liquid jet and entrained gas bubbles impinge against it.

4. A device for producing high frequency vibrations in a liquid medium comprising a container for the medium, a diaphragm positioned within the container and capable of vibrating at high frequency, and means for directing against said diaphragm a jet of incompressible liquid containing a compressible gas.

5. A device according to claim 4 in which the diaphragm is a conical member of flexible material.

6. A device according to claim 4 in which the diaphragm is a rigid conical member flexibly supported within the container.

FRANCIS GEORGE FIRTH.

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

UNITED STATES PATENTS Number Name Date 899,820 Abbott, Jr Sept. 29, 1908 1,445,096 McKerahan Feb. 13, 1923 1,475,385 Hecht et al Nov. 27, 1923