RU2250611C2 - Bird repelling method - Google Patents

Abstract

FIELD: agriculture, in particular, methods for repelling of birds from national economy objects.

SUBSTANCE: method involves attaching at least one acoustic whistle to rockets grain stabilizer, said rockets grain being launched towards stock of birds and being adapted for burning in vibrational mode. Geometric sizes of whistles provide for required amplitude-frequency characteristics of sound. During flying of said device, approach air stream passes through whistles and periodically generates acoustic signals simulating cries of predatory birds and attracting additional attention of birds to be repelled to silhouette of device during the entire period of flight. Cries of various predatory birds may be simulated through selection of whistles with predetermined geometric sizes.

EFFECT: increased efficiency and simplified method.

4 dwg

Description

The present invention relates to deterrents and devices for protecting birds from airfields, agricultural land, warehouses and architectural monuments. It is known that the most effective deterrents for birds are those that combine optical and acoustic effects when using (Zvonov B.M., Shevyakov B.C. Control of bird behavior at some economically important objects. Methodical recommendations).

A known method of scaring birds (patent No. 2140151), which consists in the fact that to the powder canal, which generates sound vibrations simulating the screams of birds during the vibrational mode of combustion, they attach a flight stabilizer and run towards the accumulation of birds, scaring them with artificial distress screams generated a burning saber, as well as a fire torch, an approaching silhouette and an additional noise clap in the immediate vicinity of the birds.

The increased efficiency of the known method is achieved by the simplicity of the design used and the combination of the most frightening optical and acoustic effects on birds in one device.

Due to the fact that when the checkers are burned according to the known method, the silhouette of the entire device with a torch and stabilizer flies directionally to a distance of about 1 km, one operator with binoculars can control the ornithological situation at the airport day and night and in any weather.

However, the actual deterrent effect of the known method can be increased while maintaining all its advantages.

A powder checker providing the required flight range and an acoustic signal with the required characteristics, according to the known method, cannot generate an acoustic signal for longer than 1 second. The rest of the flight time (about a minute before the powder cracker is triggered in the immediate vicinity of the birds) the entire assembly does not generate frightening sounds or screams of distress.

According to the proposed method, an acoustic whistle (figure 2) or several whistles of different designs and capacities are installed on the stabilizer next to or in front of the powder checker (figure 1). The whistles generate acoustic signals during the flight of the device by the incoming air flow and attract additional attention of birds to the repelling device.

The increased efficiency of the proposed method is achieved not only by the fact that the acoustic whistle periodically attracts additional attention of birds throughout the flight, but also by the fact that, as will be shown below, it generates sounds imitating the cries of birds of prey, for example, a wide-winged falcon.

It is known (Collection “Acoustic Coagulation of Particles.” M .: State publication of Chemical Literature, 1961, Research Institute for Industrial and Sanitary Cleaning of Gases NIIOGAZ) that the speed of an air stream passing through a whistle should correspond to an odd number of half-periods of sound emitted by a whistle. Only in this case the whistle emits a sound, “whistles”.

This feature of the whistle can be easily checked by increasing the speed of the jet. Starting at a certain speed, you can hear the first very weak whistle, which then completely stops when the jet speed continues to increase. Then, with a further increase in jet velocity, a sound of the same frequency appears again, but much more intense. With a further increase in jet velocity, this sound again stops completely, etc.

This means that the whistles that are installed on the flying device according to the proposed method will generate sound (or will not) depending on the flight speed (speed of the incoming air flow) in different parts of the trajectory. In this case, it is necessary to select for the sections of the flight path of the device and flight speeds different designs of whistles to affect specific types of birds.

In any case, a device that spontaneously “squeals” in flight sounds like a living flying threat to birds and is effective.

For the “police” whistle (Fig. 2) from the work of H.V. St. Clair (“Coagulation of particles of smoke, fog and dust by sound waves”, collection “Acoustic coagulation of particles”, M. State publication of the Chemical literature, 1961 , Research Institute for Industrial and Sanitary Cleaning of Gases NIIOGAZ) we give some of its characteristics.

Air flow through the whistle is 0.002 m ³ / s; sound pressure level 110 dB; acoustic power 1.13 W; efficiency 13%.

The following characteristics give the same characteristics for a whistle operating at a frequency of 3900 Hz: flow rate 0.000375 m ³ / s, sound pressure 100 dB, acoustic power 0.118 W, efficiency 28%

These figures are not only important for the application of whistles by the proposed method, but also allow us to estimate the flight speed at which they will generate acoustic signals.

For example, according to the known air flow through the whistle of 0.002 m ³ / s, knowing the nozzle area of the “police” whistle is 113.88 10 ^-6 m ² , it is easy to calculate the air flow rate at which such an amount of air passes through this area in a second.

Per second of time: 0.002 m ³ = 13.88 · 10 ^-6 m ² × V.

The desired value (air flow rate) V = 17.6 m / s. The flight speed at which the entire device according to the proposed method will generate an additional acoustic signal from the “police” whistle should be a multiple of 17.6 m / s.

For another whistle, the same calculation gives:

With a nozzle area (3 by 11 mm) of 33 · 10 ^-6 m and a flow rate of 0,000375 m / s.

Per second of time: 0,000375 m ³ = 33 · 10 ^-6 m ² × V;

The desired value (air flow rate) V = 11.36 m.

The flight speed at which the entire device with RDBK will generate an additional acoustic signal from the second whistle should be a multiple of 11.36 m / s.

This means that when additional whistles are installed on a flying device, for example, “police” and “reduced” (the second of those considered), the device will work as follows.

At startup, the device takes off at a speed greater than 100 m / s, in about 1 second it picks up a maximum speed of about 200 m / s and then flies towards the flock of birds as a freely abandoned body. For the first second of flight, the device generates a sound signal simulating a cry of distress of birds. Birds, having heard such a signal, usually do not immediately fly away, and the alarmed quickly rise into the air to understand what is happening. At this time, a flying device approaches them (birds see a flight stabilizer with a colored torch). Due to air resistance and as it approaches birds, the device loses speed from 200 m / s to almost 1 m / s, then when approaching the surface of the earth the speed of the device increases again. At the same time, reaching speeds that are multiples of 17.6 m / s and 11.36 m / s, it periodically generates acoustic signals at frequencies, for example, 2900 Hz and 3900 Hz, attracting attention and simulating a live threat to birds with a moving silhouette in combined with an imitation of a scream, such as a wide-winged falcon. 3, asterisks indicate the flight paths of the device at which the acoustic whistle generates these signals.

Birds, having heard the first signal from a powder cannon and taking off, usually make circles over the place from which they took off or over the place from which the distress cry was heard (Fig. 3). At the same time, part of the bird flock may be (and turns out to be) next to the device flying and periodically whistling like a falcon and is more afraid of others. For black bird species that respond to danger with the whole flock, this is enough. The birds, frightened more than others, carry away the whole flock.

Further, in the immediate vicinity of individuals still hesitating to flee, a clapper of smoke powder, which also has a flying device, is noisy and abruptly triggered (with the rapid formation of a white smoke cloud).

According to the proposed method, depending on the specific type of bird, simple acoustic whistles, similar to those already described, cartridge cartridges, as well as home-made wooden whistles, familiar to everyone from childhood, can be installed on the flight stabilizer of a deterrent device.

Figure 4 shows for comparison the recorded and processed acoustic signal generated by the whistle and the cry of the wide-winged falcon (from the page htth: //www.math.sunysb.edu/tony/birds).

Comparison shows that the acoustic signal generated during the flight is very close to the shout of a wide-winged falcon by the nature of the change and frequency characteristics.

From the already cited collection “Acoustic Coagulation of Particles” it is known that the natural frequency (and other characteristics) of a sound in a whistle, like a resonator, depends on its volume and geometric dimensions.

Given the information shown in figure 4, this means that by selecting certain geometrical sizes of the whistle and providing the required flight speed of the device with a whistle, it was possible to imitate the cry of a wide-winged falcon. As we have seen, this cry (as well as its artificial imitation) is effective, for example, in urban conditions for dispersing pigeons (sizars).

Even a slight change in the internal geometry of the whistle leads to a change in its acoustic characteristics and a noticeable (by pigeons) decrease in its effectiveness.

On the other hand, according to the proposed method, it remains possible to simulate screams and other birds of prey by changing the geometry of the whistle and the flight speed characteristics of the device with a whistle (htth: //www.math.sunysb.edu/tony/birds).

Since the device, with a whistle selected for a certain bird species, flies and periodically throughout the flight simulates a scream, for example, of a wide-winged falcon, by changing its speed characteristics it is possible to achieve intervals between simulated cries close to the intervals of falcon's cries, which is important for performing the task of increasing the effectiveness of the scare method.

Claims (1)

A method of scaring away birds, namely, that a flight stabilizer with one or several whistles is attached to the powder canal burning in vibration mode and launched in the direction of the accumulation of birds, frightening them with an artificial distress call generated by a burning checker, and periodic acoustic signals generated acoustic whistles, as well as a fire torch, an approaching silhouette and an additional noise clap in the immediate vicinity of birds, characterized in that in flight by acoustic whistles with selected geometrical characteristics imitate the cries of birds of prey, for example, a wide-winged falcon, and due to this, they increase the repellent effect.

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