GB2540737A

GB2540737A - An anemometer

Info

Publication number: GB2540737A
Application number: GB1511828.4A
Authority: GB
Inventors: Charles Robert Stickland Anthony
Original assignee: GILL INSTR Ltd
Current assignee: GILL INSTR Ltd
Priority date: 2015-07-06
Filing date: 2015-07-06
Publication date: 2017-02-01
Also published as: GB201511828D0

Abstract

An anemometer comprising a planar support 12 which supports a multiplicity of ultrasonic transducers 14, 16, 18, 20, 22, 24. A reflector 26 is spaced from the support and is fixed in position by at least one spacer 28. The ultrasonic transducers are electrically connected to a control and measurement microprocessor and are oriented to send ultrasonic waves towards the reflector and to receive reflections of those waves. The ultrasonic transducers are spaced apart around the spacer, and provide at least three transmitter-receiver pairs whose ultrasound transmission paths are located outwardly of and around the spacer. The invention reduces the effect of wind turbulence caused by the spacer on the measurements. Preferably, there is only one spacer which may be elongate and cylindrical. There may be six ultrasonic transducers, each comprising both an ultrasonic transmitter and receiver. The six transducers may form three pairs of transducers in an equilateral triangle arrangement. The spacing between adjacent transducers may be such that the distance between their vibratory surfaces is greater than the width of the spacer.

Description

An anemometer [0001] The present invention relates to an anemometer comprising a generally planar support which supports a multiplicity of ultrasonic transducers, and a reflector device spaced apart from the support and fixed in position relative to the support by at least one spacer, in which the ultrasonic transducers are electrically connected to a control and measurement microprocessor and are so oriented as to send ultrasonic waves towards the reflector device and to receive reflections of those waves from the reflector device.

[0002] Such an anemometer is disclosed in JPH10132839A. However, in the construction of anemometer disclosed therein, the arrangement of the spacers is such that they will cause turbulence that will adversely affect the readings taken, especially in the measurement of high wind speeds.

[0003] The present invention seeks to provide a remedy.

[0004] Accordingly, the present invention is directed to an anemometer comprising a generally planar support which supports a multiplicity of ultrasonic transducers, and a reflector device spaced apart from the support and fixed in position relative to the support by at least one spacer, in which the ultrasonic transducers are electrically connected to a control and measurement microprocessor and are so oriented as to send ultrasonic waves towards the reflector device and to receive reflections of those waves from the reflector device, characterised in that the ultrasonic transducers are spaced apart around the spacer, to provide at least three transmitter-receiver pairs the transmission paths of which are located outwardly of the spacer and are arranged around the spacer.

[0005] Such an anemometer provides at least two transmitter-receiver pairs the measurements from which are substantially unaffected by wind turbulence caused by the spacer even in high winds, regardless of the wind direction, enabling the anemometer to resolve the wind direction and speed, in other words to measure the wind velocity.

[0006] The support may be generally circular.

[0007] This results in such turbulence as arises being substantially the same in all directions, facilitating a turbulence correction by the microprocessor.

[0008] This is especially so if the reflector device is also circular.

[0009] The transducers may be located adjacent to the periphery of the support.

[0010] This makes full use of the spacing between transducers which is available, thus improving the resolution of measurements made by the anemometer.

[0011] In use, the anemometer may be oriented with the support uppermost, or the reflector device uppermost.

[0012] There may be just one spacer. This keeps turbulence low.

[0013] This is so more especially if there is just one spacer, of circular cross section.

[0014] More especially there may be just one spacer, which may be elongate and cylindrical, of uniform circular cross section, extending between the support and the reflector device.

[0015] There may be six ultrasonic transducers supported on the support.

[0016] These can provide the three pairs of transducers .

[0017] Each ultrasonic transducer may comprise an ultrasonic transmitter/receiver, which can both transmit and receive ultrasonic signals.

[0018] This provides an efficient use of devices, and enables such turbulence as the transducers may cause to be kept relatively low.

[0019] This is especially so if there are six ultrasonic transducers supported on the support in such a fashion as to constitute three pairs of transducers, such that each transducer of each pair is so oriented that it can both transmit signals to and receive signals from the other of that pair, in each case by way of reflection from the reflector device.

[0020] The respective three mid-points between the two transducers of those three pairs may lie on the apices of an imaginary equilateral triangle with the spacer or the spacers located at the centre of that triangle.

[0021] This may result in the transmission paths of the transmitter-receiver pairs being equiangularly positioned around the spacer, so that microprocessor can interpret the signals from the different pairs in the same way.

[0022] This is especially so if the respective three mid-points between two adjacent transducers of adjacent pairs of those three pairs of transducers also lie on the apices of an imaginary equilateral triangle.

[0023] The spacing between such adjacent transducers may be such that the distance between their respective vibratory surfaces is greater than width of the spacer or the combined width of the spacers.

[0024] Such a construction reduces such turbulence as affects measurements from such adjacent transducers.

[0025] Examples of anemometers each embodying the present invention will now be described in greater detail with reference to the accompanying drawings, in which: [0026] Figure 1 is an elevational view of one example of an anemometer which embodies the present invention; [0027] Figure 2 is a cross-section of the anemometer shown in Figure 1 taken in the plane indicated by the line II-II in that Figure; [0028] Figure 3 is an isometric view of the anemometer shown in Figures 1 and 2, from above and to one side; [0029] Figure 4 shows electronic circuitry of the anemometer shown in Figures 1 to 3; [0030] Figures 5 and 6 show respective further embodiments of the present invention, diagrammatically; [0031] Figure 7 is an elevational view of a modified form of the anemometer shown in Figures 1 to 3, also embodying the present invention; and [0032] Figure 8 is a cross-sectional view of the anemometer shown in Figure 7 taken in the plane indicated by the line VIII-VIII in that Figure.

[0033] The anemometer 10 shown in Figures 1 to 3 comprises a generally circular planar support 12 on an upper generally planar main face of which are mounted six part-spherical ultrasonic transducers 14, 16, 18, 20, 22 and 24. A generally circular reflector disc 26 is secured to the support 12 by a spacer in the form of a cylindrical pillar 28 which is of uniform circular cross-section.

[0034] Each of the six ultrasonic transducers both transmit and receive ultrasonic waves when the anemometer is in use.

[0035] The support 12 and the reflector disc 26 are of the same general thickness, and their edges are rounded to reduce turbulence when the anemometer is placed in high winds .

[0036] Ultrasonic transducers 16 and 18 constitute a first pair of transducers, ultrasonic transducers 20 and 22 constitute a second such pair, and ultrasonic transducers 24 and 14 a third pair. The transducer of each pair has the central perpendicular of its planar vibratory surface 27 at an angle of 45° to the upper main horizontal face of the circular support 12, directly towards the other transducer of that pair as viewed from above, so that an ultrasonic signal transmitted from that transducer is reflected off the underside of the reflector disc 26 towards the other ultrasonic transducer of the pair.

[0037] The perpendicular bisectors of the three respective lines joining the two transducers of each of the three pairs of transducers pass through the central axis of the pillar 28. These three lines lie on an imaginary equilateral triangle the centre of which coincides with the central axis of the pillar 28. As a result, the midpoints of these three lines lie on the apices of an imaginary equilateral triangle, as do the midpoints of the three lines which join adjacent transducers of adjacent pairs. Thus, the midpoint between transducers 16 and 18, the midpoint between transducers 20 and 22, and the midpoint between transducers 24 and 14 lie on the respective apices of an imaginary equilateral triangle. Also, the midpoint between transducers 14 and 16, the midpoint between transducers 18 and 20, and the midpoint between transducers 22 and 24 also lie on the respective apices of an imaginary equilateral triangle.

[0038] The spacing between the vibratory surfaces of ultrasonic transducers 14 and 16, and also the spacing between the vibratory surfaces of the ultrasonic transducers 18 and 20, and also the spacing between the vibratory surfaces of the ultrasonic transducers 22 and 24, is greater than the cross-sectional diameter of the pillar 28 .

[0039] The spacing between the transducers of any pair is the same as the spacing between the transducers of each other pair. The spacing between adjacent transducers of any two adjacent pairs is the same as the spacing between adjacent transducers of either of the other two adjacent pairs.

[0040] The electronic circuitry shown in Figure 4 indicates quite simply that each transducer 14, 16, 18, 20, 22 and 24 is electrically connected to a control and measurement microprocessor 30 of the anemometer shown in Figures 1 to 3, so that the latter can send signals to and receive signals from all the transducers.

[0041] When the anemometer shown in Figures 1 to 4 is in use, with the anemometer fixed on a post (not shown) with its support disc 12 and reflector disc 26 oriented horizontally and with the reflector disc 26 uppermost, the microprocessor 30 causes each transducer 14 to 24 in turn to transmit an ultrasonic signal, and to measure the time it takes for that signal to be reflected from the reflector disc 26 to the other transducer of the pair. Since the electronic conversion of these times to an indication of wind speed and direction will be readily apparent to a person skilled in the art of anemometers from the illustrated construction, it will not be described in detail. This conversion is effected by the microprocessor 30.

[0042] Numerous variations and modifications to the anemometer illustrated in Figures 1 to 4 may occur to the reader without taking the resulting construction outside the scope of the present invention. Two such modifications are shown respectively in Figures 5 to 6. In these modifications, there are only three transducers 34, 36 and 38 seated within the support 12 so that their vibratory surfaces 27 are flush with the upper main surface of the support 12. This ensures that substantially no turbulence is created by these transducers. They are located on the apices of an imaginary equilateral triangle. In these constructions, transducers 34 and 36 constitute a first transmitter-receiver pair (between which signals may pass from transducer 34 to transducer 36, as well as from transducer 36 to transducer 34), transducers 36 and 38 a second pair (signals again being passable between them in both directions), and transducers 38 and 34 a third pair (signals again being passable between them in both directions) .

[0043] In the modification shown in Figure 5, above each transducer on the reflector disc 26, there is a shallow protuberance 40 having reflective surfaces 42 and 44 angled to reflect ultrasonic waves emanating upwardly from the transducer it is situated above, to the other two transducers.

[0044] In the modification shown in Figure 6, these reflective surfaces 42 and 44 are such as to reflect ultrasonic waves emanating upwardly from the transducer that the protuberance 40 is situated above, towards the other two protuberances .

[0045] In the modified anemometer shown in Figures 7 and 8, the ultrasonic transducers 14 and 16 are replaced by one single ultrasonic transducer 50, the ultrasonic transducers 18 and 20 are replaced by one single ultrasonic transducer 52, and the ultrasonic transducers 22 and 24 are replaced by on single ultrasonic transducer 54. The transducers 50, 52 and 54 are provided with respective vibratory surfaces 56 each of which transmits a wide enough beam of ultrasound for the ultrasound to reach the vibratory surfaces 5 6 of both the other two transducers after the ultrasound has been reflected by the reflector disc 26, the vibratory surface 56 of each transducer 5 0, 52 and 5 4 also being sensitive to receive ultrasound from the vibratory surfaces of the other two transducers after it has been reflected by the reflector disc 26.

[0046] Instead of the vibratory surfaces 56 each being able to transmit a wide beam of ultrasound, and to receive ultrasound within a wide angle, the vibratory surface 56 of each transducer 50, 52 and 54 may be so formed that the strength of transmission of ultrasound from the surface and the sensitivity of the surface to received ultrasound as a function of angle about the surface in polar co-ordinates are both in the form of two lobes with maximum values in the respective directions of the other two transducers via reflection from the reflector disc 26.

[0047] Such a modification operates by the microprocessor 30 causing the issuance of an ultrasonic signal from each transducer 50, 52 and 54 in turn, with the microprocessor 30 being used to measure the respective times taken for the signal to reach the other two transducers, the wind speed and direction being determined from these measurements.

Claims

Claims:

1. An anemometer comprising a generally planar support which supports a multiplicity of ultrasonic transducers, and a reflector device spaced apart from the support and fixed in position relative to the support by at least one spacer, in which the ultrasonic transducers are electrically connected to a control and measurement microprocessor and are so oriented as to send ultrasonic waves towards the reflector device and to receive reflections of those waves from the reflector device, characterised in that the ultrasonic transducers are spaced apart around the spacer, to provide at least three transmitter-receiver pairs the transmission paths of which are located outwardly of the spacer and are arranged around the spacer.

2. An anemometer according to claim 1, in which the support is circular.

3. An anemometer according to claim 2, in which the reflector device is also circular.

4. An anemometer according to any preceding claim, in which the transducers are located adjacent to the periphery of the support.

5. An anemometer according to any preceding claim, in which the anemometer is oriented with the support uppermost when in use.

6. An anemometer according to any one of claims 1 to 4, in which the anemometer is oriented with the reflector device uppermost when in use.

7. An anemometer according to any preceding claim, in which there is only one spacer.

8. An anemometer according to claim 7, in which the spacer is of circular cross section.

9. An anemometer according to claim 8, in which the spacer is elongate and cylindrical, of uniform circular cross section, extending between the support and the reflector device.

10. An anemometer according to any preceding claim, in which there are six ultrasonic transducers supported on the support.

11. An anemometer according to any preceding claim, in which each ultrasonic transducer comprises an ultrasonic transmitter/receiver, which can both transmit and receive ultrasonic signals .

12. An anemometer according to claim 11 read as appended to claim 10, in which six ultrasonic transducers are supported on the support in such a fashion as to constitute three pairs of transducers, such that each transducer of each pair is so oriented that it can both transmit signals to and receive signals from the other of that pair, in each case by way of reflection from the reflector device.

13. An anemometer according to claim 12, in which the respective three mid-points between the two transducers of those three pairs lie on the apices of an imaginary equilateral triangle with the spacer or the spacers located at the centre of that triangle.

14. An anemometer according to claim 13, in which the respective three mid-points between two adjacent transducers of adjacent pairs of those three pairs of transducers also lie on the apices of an imaginary equilateral triangle.

15. An anemometer according to claim 14, in which the spacing between such adjacent transducers is such that the distance between their respective vibratory surfaces is greater than the width of the spacer or the combined width of the spacers.

16. An anemometer substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 4, or Figure 5, or Figure 6, or Figures 7 and 8 of the accompanying drawings .