ULTRASONIC PEST CONTROL DEVICE AND METHOD FOR CONSTRUCTING THE SAME

The field of the present invention is ultrasonic transmitters and, more particularly, ultrasonic pest control devices and methods for constructing the same.

It is well known that pest infestation is a primary cause of damage to stored materials and foodstuffs each year, and that damage resulting from pest infestation causes the agricultural and food and beverages industries, both in this country and worldwide, to suffer substantial losses each year. In addition, it is well known that many pests, including rodents, insects, and birds, find ultrasonic sound waves of certain frequencies to be disturbing or unpleasant, and that under the right conditions ultrasonic sound waves may be used to drive pests away from a given area. For this reason, numerous electronic and mechanical ultrasonic pest control devices have been developed as a means for driving pests away from food and materials storage facilities. However, these prior devices have not proven to be as reliable, economical to manufacture, and capable of ready adaptation to a broad range of environments as is desirable.

For example, those skilled in the art will appreciate that electronic ultrasonic pest control devices are prone to damage and disfunction at preferred output intensities. More specifically, it has been found that to drive pests away from a given area it is preferable to bathe the area in ultrasonic waves having a magnitude of at least 100 db, and that, while some electronic devices are capable of bathing small areas in ultrasonic waves of sufficient magnitude, these devices simply will not withstand operation at output intensities sufficient to cover large areas.

With respect to non-electronic ultrasonic pest control devices, those skilled in the art will appreciate that the issue is not operability or reliability, as numerous ultrasonic whistles have been developed and are capable of producing ultrasonic outputs in the magnitude ranges suggested above. Instead, the issues are cost, ease of manufacture, and ease of customization to a given area or volume of interest. As shown in United States Patent No. 3,138,138, issued to Quittner (hereinafter the "Quittner patent"), and in United States Patent No. 3,277,861, issued to Moe (hereinafter the "Moe patent"), conventional ultrasonic "whistle based" devices generally comprise a source of compressed fluid (air in most cases), an internal tubing network, a valve assembly, and one or more ultrasonic whistles. In use, the compressed fluid source delivers fluid under pressure to the tubing network, the tubing network conveys the fluid to the whistle or whistles, and the valve assembly provides a means for controlling the volume of the fluid which is delivered to the whistle or whistles from the tubing network. Although the assembly of these devices is relatively simple and straight forward, it will be noted that difficulties may arise in customizing these devices to treat areas of varying sizes and dimensions or to rid an area of multiple types of pests. For example, the devices disclosed in the Quittner and Moe patents must be modified substantially to direct sound waves bi-directionally or multi-directionally. Further, it will be noted that the bonding or welding of the tubes comprising the ultrasonic pest control devices of the prior art is a labor intensive and time consuming process.

Accordingly, a need exists for an improved ultrasonic transmitter, and in particular, a need exists for an improved ultrasonic pest control device, which may be readily manufactured or modified to meet the needs of a given area of pest infestation.

FR-A-1 131 551 discloses an ultrasonic device comprising two blocks which, when coupled together, form therebetween an ultrasonic whistle in fluid communication with a manifold and an acoustic horn.

Accordingly, it is an object of the present invention to provide an improved ultrasonic pest control device and methods for constructing the same.

The present invention is directed to an improved ultrasonic pest control device according to Claim 1, and to methods for constructing the same according to Claim 5. To this end, an ultrasonic pest control device embodying a form of the present invention comprises a plurality of blocks which, when coupled together, form at least one ultrasonic whistle in fluid communication with a manifold and an acoustic horn. Importantly, by varying the number of ultrasonic whistles formed between the blocks, it is possible to substantially increase or decrease the intensity of the ultrasonic waves produced by the device. Thus, the ultrasonic pest control device of the present invention may be readily adapted to drive pests from either a large or small area. Further, if the dimensions of the ultrasonic whistles are varied, the ultrasonic waves generated by the respective ultrasonic whistles will vary in frequency and will interact to form an ultrasonic wave having a modulated frequency or, stated differently, a sound having a polychromatic content. This may be advantageous, as it has been found that, if pests are exposed over long periods of time to ultrasonic waves of a single frequency, the pests will often adapt or develop a deafness immunity to ultrasonic waves of that frequency. In contrast, when pests are exposed to ultrasonic waves of different frequencies, the pests are less likely to adapt or acquire deafness immunity. Finally, as will be set forth more fully below, it may be noted that by changing the shape of the blocks, and also by providing additional ultrasonic whistles, the ultrasonic pest control device of the present invention may be altered to provide for bidirectional or even multidirectional transmission. Accordingly, an ultrasonic pest control device in accordance with the present invention may be readily adapted to meet not only the requirements of areas varying in size, but also the requirements of areas varying in shape.

In a preferred form, the ultrasonic pest control device of the present invention comprises a plurality of blocks which are capable of mating, e.g., in a tongue and groove fashion, and which have a plurality of cuts formed therein. The cuts comprise various portions of at least one ultrasonic whistle, and when the blocks are mated, the cuts combine to form the at least one ultrasonic whistle. Further, at least one block of the plurality has a manifold formed therein, and at least one block of the plurality has an acoustic horn formed therein. The acoustic horn is capable of fluid communication with one of the cuts forming the at least one ultrasonic whistle, and the manifold is capable of fluid communication with at least another of the cuts forming the ultrasonic whistle. As indicated above, and explained in still further detail below, by varying the shape of the blocks, and/or by providing additional ultrasonic whistles and acoustic horns, bidirectional or even multidirectional transmission of ultrasonic waves may be achieved. chamber region forms a resonating chamber, and the two bounded regions in combination form an ultrasonic whistle. In addition, the manifold region forms a section of a manifold which is open to the settling reservoir, and the horn region forms a section of an acoustic horn which is in fluid communication with the resonating chamber.

The preferred embodiment of the present invention may be modified to treat a large or small area of pest infestation by modifying the number of ultrasonic whistle functional units provided. Also, by varying the dimensions of the resonating chambers of various ultrasonic whistle functional units frequency variation may be achieved. Finally, an ultrasonic pest control device in accordance with a preferred form of the present invention may be readily adapted to provide for bidirectional or multidirectional transmission.

• Fig. 1(a) illustrates an ultrasonic whistle functional unit in accordance with a preferred form of the present invention.
• Fig. 1(b) is a cross-sectional view of an ultrasonic whistle functional unit in accordance with a preferred form of the present invention.
• Fig. 2 is an illustration of an ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 3(a) is an illustration of a manifold block which forms one portion of an ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 3(b) is a top view of a manifold block which forms one portion of an ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 3(c) is a cross-sectional view of a manifold block which forms one portion of an ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 4(a) is an illustration of a horn block which forms one portion of an ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 4(b) is a bottom view of a horn block which forms one portion of an ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 4(c) is a cross-sectional view of a horn block which forms one portion of an ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 4(d) is a top view of a horn block which forms one portion of an ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 5 illustrates a corner mounted ultrasonic transmitter in accordance with a preferred form of the present invention.
• Fig. 6 illustrates the connection of an ultrasonic transmitter in accordance with the present invention to a pressurized fluid source.
• Fig. 7 (a) illustrates the connection of a plurality of ultrasonic transmitters along a common fluid source line.
• Fig. 7 (b) illustrates the connection of a plurality of ultrasonic transmitters to separate fluid source lines.

Turning now to the drawings, Figs. 1(a) and 1(b) provide illustrations of an ultrasonic whistle functional unit 1 in accordance with a preferred form of the present invention. The ultrasonic whistle functional unit 1 comprises a manifold 2, a settling chamber 4, a resonating chamber 6, and an acoustic horn 8. In use, air (or any other compressible fluid) is bled from the manifold 2 into the settling chamber 4. The settling chamber 4 functions as a reservoir and has a nozzle 10 formed at one end. Neither the settling chamber 4 nor the nozzle 10 need conform to any particular shape. However, it is preferred that the walls 12 and 14 of the settling chamber 4 which form the nozzle 10 converge in some fashion such that the air delivered by the nozzle 10 across the gap 16 (between the settling chamber 4 and the resonating chamber 6) will be smoothed to a point of laminar flow. Further, to minimize turbulence within the settling chamber 4, it is preferred that the manifold 2 open into a central, rather than an end, portion of the settling chamber 4.

The nozzle 10 focuses the laminar flow of air against a knife-edge 18. As the laminar air flow engages the knife-edge 18, turbulence is produced within the air flow, and a polychromic source of sound is thereby generated.

As will be appreciated by those skilled in the art, when turbulent fluid flow occurs at or near an open end of a resonating column filled with a compressible fluid, a displacement standing wave will be produced within the column. Further, the frequency (f) of the standing wave produced may be calculated in accordance with equation (1):$$\text{f = (1/4)(}\mathit{\text{v}}\text{/}\mathit{\text{l}}\text{);}$$ where (v) represents the velocity at which the displacement standing wave travels within the fluid, and (l) represents the length of the resonating column. It follows that the turbulence produced at the opening 20 to resonating chamber 6 may be used to create displacement standing waves within the resonating chamber 6, and that the frequencies of the standing waves produced will vary as the dimensions of the resonating chamber 6 are varied. In the preferred form standing waves of a single frequency are not produced. Instead, a large number of standing waves having frequencies which fall within a given band are produced. For example, it is presently preferred that the ultrasonic whistle functional units 1 comprising the ultrasonic transmitter 22 (shown in Fig. 2) of the present invention generate standing waves having frequencies which fall within a band centered at approximately 28 kHz, as ultrasonic waves in the 28 kHz range have been found to be particularly effective in driving rats from a given area. To produce such waves it is presently preferred that the resonating chamber 6 measure approximately 3,048 mm (0.12 inches) in length L, 1,524 mm (0.06 inches) in width W, and 2,54 mm (0.10 inches) in height H. It should be noted however that it is not intended to limit the scope of the present invention to any particular frequency or to any particular application, as it is believed that the general concept of the invention may be implemented at any of a number of frequencies, that the concept of the invention may be used to rid a given area of any of a number of pests, including (for example) other rodents, insects, and birds, and that the general concept of the invention may prove to be advantageous in many other ultrasonic applications.

Finally, the resonating cavity 6 and its associated knife-edge 18 are coupled through the fluid medium (air) to the acoustic horn 8. The acoustic horn 8 acts as an impedance matching device which efficiently transfers the acoustic energy generated by the displacement standing waves to the surrounding environment. Although the acoustic horn 8 depicted in the drawings has a conical shape or profile, it may be advantageous to alter the shape of the acoustic horn 8. For example, it may be desirable to utilize an acoustic horn 8 having an exponential shape or profile.

Turning now to Fig. 2, in a preferred form the ultrasonic transmitter 22 of the present invention comprises a pair of blocks 24 and 26 which are capable of mating in a tongue and groove fashion, and which have a plurality of cuts 28, 30, 32, and 34 (shown in Figs. 3(a)-(c), and 4(a)-(d)) formed therein. The cuts 28, 30, 32, and 34 comprise various portions of at least one ultrasonic whistle functional unit 1, and when the blocks 24 and 26 are mated, the cuts 28, 30, 32, and 34 combine to form the at least one ultrasonic whistle functional unit 1.

More specifically, as shown in Figs. 3(a)-(c), and 4(a)-4(d), in a preferred form the ultrasonic transmitter of the present invention comprises a manifold block 24 and a horn block 26. The manifold block 24 has a hole 36 comprising a manifold 2 formed therein. The hole 36 is formed in one side S1 of the manifold block 24 and extends inwardly beneath the upper face F1 of the manifold block 24. The upper face F1 of the manifold block 24 comprises two surfaces 38 and 40 separated by a channel 42. Notably, in the preferred form one surface 38 is elevated above the other surface 40, and a plurality of parallel, arcuate cuts or slots 28, are formed in the less elevated surface 40. The arcuate cuts 28 are spaced equidistantly from one another and extend downwardly through the manifold block 24 to the hole 36. Accordingly, fluid communication is achieved between the arcuate cuts 28 and the manifold hole 36.

The horn block 26 has an acoustic horn 44 formed in its upper face F2 and a plurality of cuts 30-34 formed in its lower face F3. The lower face F3 of horn block 26, which is shaped to fit tightly against the upper face F1 of the manifold block 24 in a tongue and groove fashion, comprises two surfaces 46 and 48 separated by a raised tongue 50. The surface 48, which fits against the less elevated surface 40 of the manifold block 24, when the blocks 24 and 26 are coupled together, has a primary arcuate cut 30 and a plurality of secondary arcuate cuts 32 formed therein. The primary arcuate cut 30 is disposed adjacent the raised tongue 50 and extends through the horn block 26 to a base portion 52 of the acoustic horn 44. The secondary arcuate cuts 32 are equidistantly spaced and intersect the primary cut 30 at one end 54. In addition, the secondary arcuate cuts 32 are spaced and dimensioned such that they correspond to the arcuate cuts 28 formed in the manifold block 24. Thus, when the blocks 24 and 26 are coupled together, the respective arcuate cuts 28 and 32 combine to form the settling chambers 4 of a plurality of ultrasonic whistle functional units 1. Finally, a plurality of arcuate cuts 34 are also formed in the raised tongue 50. The arcuate cuts 34 located in the raised tongue 50 are collinear with and have the same width as the secondary arcuate cuts 32 formed in the surface 48. Thus, when the raised tongue 50 is received by the channel 42 (i.e. when the blocks 24 and 26 are coupled together), the arcuate cuts 34 disposed in the raised tongue 50 form the resonating chambers 6 of a plurality of ultrasonic whistle functional units 1. In addition, the edges 56 of the arcuate cuts 34 which border the primary arcuate cut 30 form the knife-edges 18 of a plurality of ultrasonic whistle functional units 1.

In the presently preferred form, the manifold block 24 and the horn block 26 are constructed from aluminum, and the blocks are coupled together using screws 45 or by other conventional means (i.e. using bolts, glue, etc.). However, those skilled in the art will recognize that blocks 24 and 26 may be constructed from a vast number of other materials, including other metals and plastic resins. Further, the shaping of the blocks and the formation of the cuts are presently performed by conventional means. More specifically, the arcuate cuts 28, 30, 32, and 34 may be formed using a conventional radial saw having a 38,1 mm (1.5") blade radius, the acoustic horn 44 is formed using conventional scooping techniques, and the raised tongue 50 and channel 42 are formed using conventional machine tools. Finally, it should be noted that it is not intended to limit the shape of the blocks to any particular shape, as it is clear that the blocks may be formed in any of a vast number of shapes, and that the blocks may be combined in a vast number of ways. For example, the corner mounted unit 58, which is illustrated in Fig. 5, may be readily combined with other corner mounted units to produce a semi-cylindrical unit, and so on.

In the above described embodiment it is presently preferred to provide five (5) ultrasonic whistle functional units 1 within each ultrasonic transmitter 22, and it is preferred to operate each ultrasonic transmitter 22 at a pressure between 13,79 (2 psi) and 48,265 kPa (7 psi) and a fluid (air) flow rate of approximately 0,1132668 m³/min (4 ft³/min). At these operating parameters, the ultrasonic transmitter 22 of the present invention is capable of bathing a hemisphere having a radius of 30,48 m (100 ft) in ultrasonic waves having a magnitude of at least 100 db. Further, as shown in Fig. 6, a conventional low pressure fluid (air) pump 90, such as the Whisper 500, manufactured by Second Nature Inc. of Oakland, New Jersey, may be used to drive the ultrasonic transmitter 22 at the preferred operating parameters. The fluid pump 90 serves as a pressurized fluid source and may be coupled to the ultrasonic transmitter 22 by conventional means. For example, it is presently preferred to provide a threaded fitting 92 at the opening 94 of the manifold 2 (shown in Fig. 2), such that a rubber or plastic hose 96 may be readily coupled at one end 98 to the ultrasonic transmitter 22, and it is preferable to attach the other end 100 of the hose 96 to the fluid pump 90 in a similar fashion.

Finally, it will be appreciated that the ultrasonic transmitter 22 of the present invention is modular in nature. Thus, numerous devices 22 may be provided along a common line 102 as shown in Fig 7 (a), or along separate lines 104 and 105 as shown in Fig. 7 (b). The modular construction provides for a maximization of overall system efficiency, because it provides a simple and effective means for addressing acoustic obstructions, such as walls etc., within a given structure.