CA1250926A - Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof - Google Patents
Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereofInfo
- Publication number
- CA1250926A CA1250926A CA000494950A CA494950A CA1250926A CA 1250926 A CA1250926 A CA 1250926A CA 000494950 A CA000494950 A CA 000494950A CA 494950 A CA494950 A CA 494950A CA 1250926 A CA1250926 A CA 1250926A
- Authority
- CA
- Canada
- Prior art keywords
- diaphragm
- ice
- frequency
- vibration
- warning system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
- B64D15/00—De-icing or preventing icing on exterior surfaces of aircraft
- B64D15/20—Means for detecting icing or initiating de-icing
Abstract
ABSTRACT
The ice warning system comprises a diaphragm {2}
into vibration at one of its frequencies of resonance by a piezoelectric cell (3). The diaphragm (2) is thermi-cally coupled to a metallic plate (4) alternately cooled and heated respectively below and above the ambient temperature (Tu) by peltier elements (8) connected to a reversible DC current generator (11). A microprocessor (12) measures the variation of the resonance frequency caused by a deposit of ice on the diaphragm (2) during the cooling or heating periods and delivers an alarm signal whenever any variation of the frequency reaches and/or exceeds a predetermined value. The microprocessor (12) controls also the period, the magnitude and the direction of flow of the current from the current generator (11) in dependence on the ambient tempera-ture and the temperature of the diaphragm. The ice warning system is preferably utilized in the aeronauti-cal field for signaling the likelihood of natural ice formation on the engines and the wings of aircrafts.
The ice warning system comprises a diaphragm {2}
into vibration at one of its frequencies of resonance by a piezoelectric cell (3). The diaphragm (2) is thermi-cally coupled to a metallic plate (4) alternately cooled and heated respectively below and above the ambient temperature (Tu) by peltier elements (8) connected to a reversible DC current generator (11). A microprocessor (12) measures the variation of the resonance frequency caused by a deposit of ice on the diaphragm (2) during the cooling or heating periods and delivers an alarm signal whenever any variation of the frequency reaches and/or exceeds a predetermined value. The microprocessor (12) controls also the period, the magnitude and the direction of flow of the current from the current generator (11) in dependence on the ambient tempera-ture and the temperature of the diaphragm. The ice warning system is preferably utilized in the aeronauti-cal field for signaling the likelihood of natural ice formation on the engines and the wings of aircrafts.
Description
~O~J~ f 7~
23~4-258 The present inventlon relates to a process for detectiny the likelihood of natural ice formatiorl on -the surface oE a vehicle, to a warning system for carrying the process and to a utilization thereof.
The process comprises the steps of: positioniny a diaphragm having a fundamental resonant frequency and harrnonic frequencies on the surface of said vehicle which is exposed to ambient temperature and to natural ice formation, exciting said diaphragm at one of said frequencies of resonance, alternately cooling and heating said diaphragm such that its temperature falls below and rises above, respectively, the temperature of said surface in accordance with a predetermined repetitious cycle to artificially create and then melt an accretion of ice when the ambient temperature is near or below the freezing point, measuring any variation in said one resonant frequency of vi-bration of the diaphragm during said step of alternately and repetitiously cooling and heating the diaphragm, signaling an alarm whenever said variation reaches and/or exceeds a predeter-mined value.
The ice warning system comprises a transducer adapted to be secured to said vehicle, said transducer comprising a diaphragm, and a vibration exciting means, .said diaphragm being responsive to said vibration exciting means for vibrating at one of its frequencies of resonance, said vibration exciting means genera-ting a vibration having a frequency equal to said frequency of resonance of said diaphragm, means for measuring the ambient 0~
temperature in the vicinity of said vehicle, means -thermall~
coupled to said diaphragm for alternately cooling and heating said diaphragm respectively below and above said ambient tempera-ture, said alternate cooling and heating occurriny in a predetermined, -la-¢3'~
repetitious cycle which is operable, under conditions where natural ice formation is likely co occur, to artificially create an accretion of ice on said dia-phragm during said cycle, frequency measuring rrleans coupled to said vibration exciting means for rneasuring any variation in the resonant frequeny of said dia-phragm, and means responsive to said frequency measuring means for signaling an alarm if the variation in the resonant frequency of the diaphragm reaches and/or exceeds a predetermined value.
The invention has a broad field of applications, more particularly but not exclusively in the aeronautical field, for example for detecting the likelihood of build up of ice on or in the engines and the wings of an airplane, which is normally a problem difficult to solve. The invention has also an application in the filed of ground and surfaces vehicles which are submit-ted to natural ice formation. The detection of ice formation is generally effected by an indirect method.
That is by measuring the air moisture and the ambient temperature. However, such a method cannot detect and measure the presence and the likelihood of a deposit of ice.
The diaphragm of the present invention is set into vibration at one of its frequencies of resonance, these frequencies of resonance being dependent on the mass and the stiffness of the diagram so that any deposit of ice on the diaphragm will change the frequency of resonance of the latter and the measurement of the variation in the frequency of resonance provides an indication of the amount of the accretion of ice. Moreover, the diaphragm is alternately submitted to variations of temperature which facilitates the detection of any artificially created deposit of ice on the diaphragm when the ambient temperature is near the freezing point and the detection of ice crystals when the ambient temperature is below the freezing point. An alarm indicating that natural ice formation is likely to occur is released when the variation of the fre~uency ok resonance reaches a predetermined value.
The invention will be described further by way of example and with reference to the accompanying drawings.
Figure 1 illustrates schematically the principle of the invention, Figure 2 and 3 show respectively a second and a third embodiment of the transducer of Figure 1.
The ice warning system comprises a transducer 1 with a metallic diaphragm 2 on the internal side of which is secured a piezoelectric cell 3. The application of an alternating voltage to the terminals of the piezoelec-tric cell sets the latter into vibration and this vibration is transmitted to the diaphragm. The diaphragm
23~4-258 The present inventlon relates to a process for detectiny the likelihood of natural ice formatiorl on -the surface oE a vehicle, to a warning system for carrying the process and to a utilization thereof.
The process comprises the steps of: positioniny a diaphragm having a fundamental resonant frequency and harrnonic frequencies on the surface of said vehicle which is exposed to ambient temperature and to natural ice formation, exciting said diaphragm at one of said frequencies of resonance, alternately cooling and heating said diaphragm such that its temperature falls below and rises above, respectively, the temperature of said surface in accordance with a predetermined repetitious cycle to artificially create and then melt an accretion of ice when the ambient temperature is near or below the freezing point, measuring any variation in said one resonant frequency of vi-bration of the diaphragm during said step of alternately and repetitiously cooling and heating the diaphragm, signaling an alarm whenever said variation reaches and/or exceeds a predeter-mined value.
The ice warning system comprises a transducer adapted to be secured to said vehicle, said transducer comprising a diaphragm, and a vibration exciting means, .said diaphragm being responsive to said vibration exciting means for vibrating at one of its frequencies of resonance, said vibration exciting means genera-ting a vibration having a frequency equal to said frequency of resonance of said diaphragm, means for measuring the ambient 0~
temperature in the vicinity of said vehicle, means -thermall~
coupled to said diaphragm for alternately cooling and heating said diaphragm respectively below and above said ambient tempera-ture, said alternate cooling and heating occurriny in a predetermined, -la-¢3'~
repetitious cycle which is operable, under conditions where natural ice formation is likely co occur, to artificially create an accretion of ice on said dia-phragm during said cycle, frequency measuring rrleans coupled to said vibration exciting means for rneasuring any variation in the resonant frequeny of said dia-phragm, and means responsive to said frequency measuring means for signaling an alarm if the variation in the resonant frequency of the diaphragm reaches and/or exceeds a predetermined value.
The invention has a broad field of applications, more particularly but not exclusively in the aeronautical field, for example for detecting the likelihood of build up of ice on or in the engines and the wings of an airplane, which is normally a problem difficult to solve. The invention has also an application in the filed of ground and surfaces vehicles which are submit-ted to natural ice formation. The detection of ice formation is generally effected by an indirect method.
That is by measuring the air moisture and the ambient temperature. However, such a method cannot detect and measure the presence and the likelihood of a deposit of ice.
The diaphragm of the present invention is set into vibration at one of its frequencies of resonance, these frequencies of resonance being dependent on the mass and the stiffness of the diagram so that any deposit of ice on the diaphragm will change the frequency of resonance of the latter and the measurement of the variation in the frequency of resonance provides an indication of the amount of the accretion of ice. Moreover, the diaphragm is alternately submitted to variations of temperature which facilitates the detection of any artificially created deposit of ice on the diaphragm when the ambient temperature is near the freezing point and the detection of ice crystals when the ambient temperature is below the freezing point. An alarm indicating that natural ice formation is likely to occur is released when the variation of the fre~uency ok resonance reaches a predetermined value.
The invention will be described further by way of example and with reference to the accompanying drawings.
Figure 1 illustrates schematically the principle of the invention, Figure 2 and 3 show respectively a second and a third embodiment of the transducer of Figure 1.
The ice warning system comprises a transducer 1 with a metallic diaphragm 2 on the internal side of which is secured a piezoelectric cell 3. The application of an alternating voltage to the terminals of the piezoelec-tric cell sets the latter into vibration and this vibration is transmitted to the diaphragm. The diaphragm
2 with the piezoelectric cell 3 is mounted to a metallic plate 4 lying on an insulator ring 6. The internal face of the ring 6 is closed by a ribbed heat sink 7. Peltier elements 8, thermically coupled to the heat sink 7 and to the metallic plate 4, are disposed within the insula-tor ring 6 between the heat sink 7 and the metallic plate 4. The diaphragm 2 which lies upon the metallic plate 4 is also thermically coupled to this plate 4. The diaphragm 2 together with the piezoelectric cell 3 is the frequency determining element of an oscillator 9 to which it is connected by leads 10. One of these leads is directly connected to the diaphragm 2 and the other lead is connected to the lower internal side of the cell
3. The Peltier elements 8 are connected to a DC current generator 11 the polarity of which is capable to be reversed. Finally, the oscillator 9 and the DC current 'f~
generator 11 are connected to a microprocessor 1Z which measures any variation in the frequency of the oscilla~
tor g and controls the period, the magnitude and the direction of current flow of the current generator 11.
A temperature sensing probe 13 ~or rneasuriny the ambient temperature Tu (illustrated schematicall~) is connected to the microprocessor 12. Another temperature probe 14 for measuring the temperature of the diaphragm 2 is also connected to the microprocessor 12. The latter delivers to its output an alarm signal whenever ice accretion on the diaphragm is present or likely to occur. The ice warning system operates as follows.
The resonance frequency of the diaphragm 2 together with the piezoelectric cell 3 is given by the relationship:
_ ~ t where ~ = pulsation = 2~ frequency f = elastic constant m = mass With regard to the preceding formula there are two different cases: a) the case in which the diaphragm is set into vibration at its fundamental frequency of resonance and b) the case in which the diaphragm is set into vibration at a higher harmonic such that the surface of the vibrating diaphragm comprises a certain number of nodes and antinodes. In the first case, if a layer of ice builds up on the diaphragm, the total mass m of the diaphragm and the piezoelectric cell increases due to the accretion of ice, and in accordance with the above formula, the frequency of the oscillator 9 decrea-ses. In the second case, the layer of ice which builds up on the diaphragm 2 increases its stiffness thus increasing the value of f. This effect predominates upon the one corresponding to the increase of the mass m so that the frequency of the oscillator 9 increases. This second case is particularly interesting because it has been ascertained that a deposit of ice only on the diaphragm leads to an increase of the frequency of the oscillator, while a deposit of other elements like water, oil or dirt leads always to a decrease of the frequency due to the increase of the mass m. Thus the invention distinguishes between the build up of ice always (except in case a) indicated by an increase of the frequency of the oscillator 9 and the presence of other elements like water, oil or dirt always indicated by a decrease of the oscillator's frequency. Any varia-tion in the frequency of the oscillator 9 is measured by the microprocessor 12 and, if it reaches and/or exceeds a predetermined value, the circuit 12 delivers at its output an alarm signal signaling the likelihood of natural ice formation on the vehicle when the ambient tmperature is near the freezing point or of ice crystals adhering to a warm surface when the ambient temperature is below the freezing point. The resonance frequency of the diaphragm is preferably between 1 and 20 kHz.
The DC current generator 11 is connected to the Peltier elements and generates a current having a period, magnitude and direction of flow determined by the microprocessor 12 as a function of measurements of the ambient temperature by the probe 13 and the temperature of the diaphragm measured by the probe 14. For a given direction of flow of the current of the generator 11, the Peltier elements cool the diaphragm 2 to a few degrees below the ambient temperature Tu and, if this ambient temperature is in the neighbourhood of the freezing point, a layer of ice may build up on the diaphragm which decreases or increases the frequency of the oscillator 9 as described previously. After a period of time, the polarity or the direction of flow of the current of the generator 11 is reversed and the Peltier ~ ~r~63 elements heat the diaphragm 2 to a few degrees above the ambient temperature in order to cause the ice previously formed to melt. The alternation of the cooling and heating phases may be periodic, the duration of these phases being in the order of a few tens of seconds. ~his provides for a periodical repetition of the measurement of the frequency of the oscillator. The transducer 1 is of relatively small dimensions so that its thermal inertia is small and the phases of cooling and heating of the diaphragm practically intantaneously follow the inversions of the direction of current flow from the DC
generator 11. The preceding shows that the device according to the invention gives a direct indication of the presence of a layer of artificially created ice on the diaphragm so that it can deliver an alarm before the occurence of a natural deposit of ice.
In practice, and more particularly in the aeronautical field, it may occur at very low temperatures of e.g.
-20C or -40C, if the air craft is flying through a cloud of ice or supercooled water droplets, that ice builds up not on the coolest parts of the aircraft like the wings but in the vicinity of the warmer engines parts. In this case, an ice warning system according to the invention which is mounted in this area may become covered by a layer of ice not during the cooling phase of the diaphragm by the Peltier elements but instead during the heating phase. However, in all cases, the frequency of the oscillator 9 decreases if the diaphragm is excited into vibration at its fundamental frequency of resonance and the frequency of the oscillator 9 increases if the diaphragm is excited into vibration at a higher harmonics.
As mentioned in the introduction, the ice warning system according to the invention is more particularly although not exclusively, utilized in the aeronautical field. In this case, a certain number of ice warning systems like the one descrlbed above are arranged on the engines or in the vicinity thereof and on the wings of the aircraft. It is possible to associate one microprocessor to each trans~
ducer or, on the contrary, to provide one single central microprocessor for all transducers. If an alarm is released, the power of the engines may be increased in order to prevent any building up of natural ice on the engines and the de-icing system in the wings and the 1n engines may be switched on to the same purpose. It is clear that if the ambient temperature rises above a determined value for which no risk of natural ice formation exists, the system is preferably switched off automatically by the microprocessor.
In Figure 1, the diaphragm is excited into vibration by a piezoelectric cell 3. Figure 2 shows that the diaphragm may also be excited into vibration electrodynamically by an inductive device 15 secured to the plate 4, connected to the oscillator 9 and having a gap with respect to the diaphragm 2 which must be of a magnetic material. Figure 3 shows a further embodiment of the device which sets the diaphragm into vibration. In this case, a magneto-strictive element 16 is secured to the diaphragm 2, this element being set into vibration by a coil 17 connected to the oscillator 9. The mechanical vibrations produced in the magnetostrictive element 16 are transmitted to the diaphragm 2 with the same frequency.
It would also be possible to heat the diaphragm by a current of relatively strong intensity or by a hot gas delivered by a system of pipes to the transducers. A
similar system of pipes in which cooling gas or liyuids are flowing could be used for cooling the diaphragm.
generator 11 are connected to a microprocessor 1Z which measures any variation in the frequency of the oscilla~
tor g and controls the period, the magnitude and the direction of current flow of the current generator 11.
A temperature sensing probe 13 ~or rneasuriny the ambient temperature Tu (illustrated schematicall~) is connected to the microprocessor 12. Another temperature probe 14 for measuring the temperature of the diaphragm 2 is also connected to the microprocessor 12. The latter delivers to its output an alarm signal whenever ice accretion on the diaphragm is present or likely to occur. The ice warning system operates as follows.
The resonance frequency of the diaphragm 2 together with the piezoelectric cell 3 is given by the relationship:
_ ~ t where ~ = pulsation = 2~ frequency f = elastic constant m = mass With regard to the preceding formula there are two different cases: a) the case in which the diaphragm is set into vibration at its fundamental frequency of resonance and b) the case in which the diaphragm is set into vibration at a higher harmonic such that the surface of the vibrating diaphragm comprises a certain number of nodes and antinodes. In the first case, if a layer of ice builds up on the diaphragm, the total mass m of the diaphragm and the piezoelectric cell increases due to the accretion of ice, and in accordance with the above formula, the frequency of the oscillator 9 decrea-ses. In the second case, the layer of ice which builds up on the diaphragm 2 increases its stiffness thus increasing the value of f. This effect predominates upon the one corresponding to the increase of the mass m so that the frequency of the oscillator 9 increases. This second case is particularly interesting because it has been ascertained that a deposit of ice only on the diaphragm leads to an increase of the frequency of the oscillator, while a deposit of other elements like water, oil or dirt leads always to a decrease of the frequency due to the increase of the mass m. Thus the invention distinguishes between the build up of ice always (except in case a) indicated by an increase of the frequency of the oscillator 9 and the presence of other elements like water, oil or dirt always indicated by a decrease of the oscillator's frequency. Any varia-tion in the frequency of the oscillator 9 is measured by the microprocessor 12 and, if it reaches and/or exceeds a predetermined value, the circuit 12 delivers at its output an alarm signal signaling the likelihood of natural ice formation on the vehicle when the ambient tmperature is near the freezing point or of ice crystals adhering to a warm surface when the ambient temperature is below the freezing point. The resonance frequency of the diaphragm is preferably between 1 and 20 kHz.
The DC current generator 11 is connected to the Peltier elements and generates a current having a period, magnitude and direction of flow determined by the microprocessor 12 as a function of measurements of the ambient temperature by the probe 13 and the temperature of the diaphragm measured by the probe 14. For a given direction of flow of the current of the generator 11, the Peltier elements cool the diaphragm 2 to a few degrees below the ambient temperature Tu and, if this ambient temperature is in the neighbourhood of the freezing point, a layer of ice may build up on the diaphragm which decreases or increases the frequency of the oscillator 9 as described previously. After a period of time, the polarity or the direction of flow of the current of the generator 11 is reversed and the Peltier ~ ~r~63 elements heat the diaphragm 2 to a few degrees above the ambient temperature in order to cause the ice previously formed to melt. The alternation of the cooling and heating phases may be periodic, the duration of these phases being in the order of a few tens of seconds. ~his provides for a periodical repetition of the measurement of the frequency of the oscillator. The transducer 1 is of relatively small dimensions so that its thermal inertia is small and the phases of cooling and heating of the diaphragm practically intantaneously follow the inversions of the direction of current flow from the DC
generator 11. The preceding shows that the device according to the invention gives a direct indication of the presence of a layer of artificially created ice on the diaphragm so that it can deliver an alarm before the occurence of a natural deposit of ice.
In practice, and more particularly in the aeronautical field, it may occur at very low temperatures of e.g.
-20C or -40C, if the air craft is flying through a cloud of ice or supercooled water droplets, that ice builds up not on the coolest parts of the aircraft like the wings but in the vicinity of the warmer engines parts. In this case, an ice warning system according to the invention which is mounted in this area may become covered by a layer of ice not during the cooling phase of the diaphragm by the Peltier elements but instead during the heating phase. However, in all cases, the frequency of the oscillator 9 decreases if the diaphragm is excited into vibration at its fundamental frequency of resonance and the frequency of the oscillator 9 increases if the diaphragm is excited into vibration at a higher harmonics.
As mentioned in the introduction, the ice warning system according to the invention is more particularly although not exclusively, utilized in the aeronautical field. In this case, a certain number of ice warning systems like the one descrlbed above are arranged on the engines or in the vicinity thereof and on the wings of the aircraft. It is possible to associate one microprocessor to each trans~
ducer or, on the contrary, to provide one single central microprocessor for all transducers. If an alarm is released, the power of the engines may be increased in order to prevent any building up of natural ice on the engines and the de-icing system in the wings and the 1n engines may be switched on to the same purpose. It is clear that if the ambient temperature rises above a determined value for which no risk of natural ice formation exists, the system is preferably switched off automatically by the microprocessor.
In Figure 1, the diaphragm is excited into vibration by a piezoelectric cell 3. Figure 2 shows that the diaphragm may also be excited into vibration electrodynamically by an inductive device 15 secured to the plate 4, connected to the oscillator 9 and having a gap with respect to the diaphragm 2 which must be of a magnetic material. Figure 3 shows a further embodiment of the device which sets the diaphragm into vibration. In this case, a magneto-strictive element 16 is secured to the diaphragm 2, this element being set into vibration by a coil 17 connected to the oscillator 9. The mechanical vibrations produced in the magnetostrictive element 16 are transmitted to the diaphragm 2 with the same frequency.
It would also be possible to heat the diaphragm by a current of relatively strong intensity or by a hot gas delivered by a system of pipes to the transducers. A
similar system of pipes in which cooling gas or liyuids are flowing could be used for cooling the diaphragm.
Claims (17)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS;
1. A process for detecting a likelihood of natural ice formation on the surface of a vehicle, more particularly an aircraft, comprising the steps of:
positioning a diaphragm having a fundamental resonant frequency and harmonic frequencies of vibration on a surface of the vehicle which is exposed to ambient temperature and to natural ice formation, exciting said diaphragm at one of said frequencies, alternately cooling and heating said diaphragm such that its temperature falls below and rises above, respectively, the temperature of said surface in accordance with a predetermined repetitious cycle to artificially create and then melt an ac-cretion of ice when the ambient temperature is near or below the freezing point, measuring any variation in said one resonant frequency of vibration of the diaphragm during said step of alternately and repetitiously cooling and heating the diaphragm, signalling an alarm whenever said variation reaches and/or exceeds a predetermined value.
positioning a diaphragm having a fundamental resonant frequency and harmonic frequencies of vibration on a surface of the vehicle which is exposed to ambient temperature and to natural ice formation, exciting said diaphragm at one of said frequencies, alternately cooling and heating said diaphragm such that its temperature falls below and rises above, respectively, the temperature of said surface in accordance with a predetermined repetitious cycle to artificially create and then melt an ac-cretion of ice when the ambient temperature is near or below the freezing point, measuring any variation in said one resonant frequency of vibration of the diaphragm during said step of alternately and repetitiously cooling and heating the diaphragm, signalling an alarm whenever said variation reaches and/or exceeds a predetermined value.
2. The process according to claim 1 further comprising the steps of:
measuring the ambient temperature, measuring the temperature of said diaphragm, controlling said step of alternately cooling and heating in accordance with a cycle the duration of said cycle being dependent on the measured ambient and diaphragm temperature.
measuring the ambient temperature, measuring the temperature of said diaphragm, controlling said step of alternately cooling and heating in accordance with a cycle the duration of said cycle being dependent on the measured ambient and diaphragm temperature.
3. The process according to claim 1 or 2, wherein the step of exciting the diaphragm at its fundamental resonant frequency of vibration produces a decrease in said fundamental resonant frequency in the presence of an accretion of ice.
4. The process according to claim 1 or 2, further comprising the step of exciting the diaphragm into vi-bration at one of its harmonic frequencies wherein the presence of an accretion of ice produces an increase of said harmonic frequency.
5. An ice warning system for carrying out the process of claim 1, comprising:
a transducer adapted to be secured to said vehicle, said transducer comprising a diaphragm, and a vibration exciting means, said diaphragm being responsive to said vibration exciting means for vibrating at one of its frequencies of resonance, said vibration exciting means generating a vibration having a frequency equal to said frequency of resonance of said diaphragm, means for measuring the ambient temperature in the vicinity of said vehicle, means thermally coupled to said diaphragm for alternately cooling and heating said diaphragm respectively below and above said ambient temperature, said alternate cooling and heating occurring in a predetermined, repetitious cycle which is operable, under conditions where natural ice formation is likely to occur, to artificially create an accretion of ice on said diaphragm during said cycle, frequency measuring means coupled to said vibration exciting means for measuring any variation in the resonant frequency of said diaphragm, and means responsive to said frequency measuring means for signalling an alarm if the variation in the resonant frequency of the diaphragm reaches and/or exceeds a predetermined value.
a transducer adapted to be secured to said vehicle, said transducer comprising a diaphragm, and a vibration exciting means, said diaphragm being responsive to said vibration exciting means for vibrating at one of its frequencies of resonance, said vibration exciting means generating a vibration having a frequency equal to said frequency of resonance of said diaphragm, means for measuring the ambient temperature in the vicinity of said vehicle, means thermally coupled to said diaphragm for alternately cooling and heating said diaphragm respectively below and above said ambient temperature, said alternate cooling and heating occurring in a predetermined, repetitious cycle which is operable, under conditions where natural ice formation is likely to occur, to artificially create an accretion of ice on said diaphragm during said cycle, frequency measuring means coupled to said vibration exciting means for measuring any variation in the resonant frequency of said diaphragm, and means responsive to said frequency measuring means for signalling an alarm if the variation in the resonant frequency of the diaphragm reaches and/or exceeds a predetermined value.
6. The ice warning system according to claim 5, wherein said diaphragm has an upper exposed side and a lower protected side and wherein said vibration exciting means includes a piezoelectric cell secured to the lower, protected side of the diaphragm and connected to said vibration exciting means, said diaphragm and said cell being a frequency determining element of said vibration exciting means.
7. The ice warning system of claim 5, wherein said diaphragm has an upper exposed side and a lower protected side and wherein said vibration exciting means includes a magneto-striction transducer secured to the lower, protected side of the diaphragm and connected to said vibration exciting means, said diaphragm and said transducer being a frequency determining element of said vibration exciting means.
8. The ice warning system of claim 5, wherein said diaphragm has an upper exposed side and a lower protected side and wherein said vibration exciting means includes an electro-dynamic transducer secured to the lower,protected side of the diaphragm and connected to said vibration exciting means, said diaphragm and said transducer being a frequency determining element of said vibration exciting means.
-
-
9. The ice warning system according to claim 5, wherein said means for cooling and heating cornprises peltier elements, and further comprising a DC current generator operably connected to said Peltier elements Eor controlling the direction of current flow to said Peltier elements, said direction of current flow being alternately reversed for effecting said cooling and heating.
10. The ice warning system according to claim 9, further comprising a first probe for measuring the ambient temperature, a second probe for measuring the temperature of said diaphragm, a microprocessor responsive to said first and second probes of controlling the duration, magnitude and direction of flow of current of said DC current generator.
11. The ice warning system according to claim 10 wherein the reversal of direction of current flow is periodic, said microprocessor determining said cycle of cooling and heating in dependence on said ambient temperature and said diaphragm ternperature.
12. Ice warning system according to claim 10, further comprising an oscillator, the frequency of which is determined by the resonant frequency of the transducerfor energizing said vibration exciting means, and wherein said frequency measuring means includes said microprocessor.
13. The ice warning system according to claim 10, wherein said microprocessor is further operable to energize a de-icing system whenever the variation in the resonant frequency reaches and/or exceeds said predtermined value.
14 the ice warning system according to clain 5, wherein claim 5, wherein said diaphragm is responsive to said accretion of ice to deerease its resonant frequeney when excited into vibration at its fundamental frequeney of resonance.
15. The ice warning system according to claim 5, wherein said diaphragm is responsive to said accretion of ice to increase its resonant frequency when excited into vibration at a higher harmonics of its fundamental frequency of resonance.
16. Utilization of a plurality of ice warning systems aeeording to claim 5 for detecting the likelihood of natural iee aecretion on airplanes.
17. Utilization of a plurality of ice warning systems according to elaim 5 for deteeting the likelihood of nature iee accretion on ground vehieles and surfaces.
Priority Applications (8)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH940/84A CH656015A5 (en) | 1984-02-27 | 1984-02-27 | Method of detecting a risk of freezing, warning device for implementing the method and its use |
| US06/607,526 US4570881A (en) | 1984-02-27 | 1984-05-07 | Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof |
| DE8585810476T DE3570777D1 (en) | 1984-02-27 | 1985-10-18 | Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof |
| AT85810476T ATE43731T1 (en) | 1984-02-27 | 1985-10-18 | PROCEDURE FOR DETERMINING THE LIKELIHOOD OF ICE FORMATION, ICE ALERT SYSTEM FOR PERFORMING THE PROCEDURE AND HOW TO USE THE SYSTEM. |
| EP85810476A EP0229858B1 (en) | 1984-02-27 | 1985-10-18 | Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof |
| CA000494950A CA1250926A (en) | 1984-02-27 | 1985-11-08 | Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof |
| SU3976888A SU1521294A3 (en) | 1984-02-27 | 1985-11-25 | Method of detecting of icing on surface and device for warning of ice formation |
| JP60267630A JPS62132148A (en) | 1984-02-27 | 1985-11-29 | Method of detecting possibility of formation of ice and ice alarm device for executing said method and utilization thereof |
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH940/84A CH656015A5 (en) | 1984-02-27 | 1984-02-27 | Method of detecting a risk of freezing, warning device for implementing the method and its use |
| EP85810476A EP0229858B1 (en) | 1984-02-27 | 1985-10-18 | Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof |
| CA000494950A CA1250926A (en) | 1984-02-27 | 1985-11-08 | Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof |
| SU3976888A SU1521294A3 (en) | 1984-02-27 | 1985-11-25 | Method of detecting of icing on surface and device for warning of ice formation |
| JP60267630A JPS62132148A (en) | 1984-02-27 | 1985-11-29 | Method of detecting possibility of formation of ice and ice alarm device for executing said method and utilization thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1250926A true CA1250926A (en) | 1989-03-07 |
Family
ID=27508242
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000494950A Expired CA1250926A (en) | 1984-02-27 | 1985-11-08 | Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4570881A (en) |
| EP (1) | EP0229858B1 (en) |
| JP (1) | JPS62132148A (en) |
| AT (1) | ATE43731T1 (en) |
| CA (1) | CA1250926A (en) |
| CH (1) | CH656015A5 (en) |
| DE (1) | DE3570777D1 (en) |
| SU (1) | SU1521294A3 (en) |
Families Citing this family (40)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1240050A (en) * | 1985-07-04 | 1988-08-02 | Yvon Cote | Microprocessor ice crust thickness measuring apparatus having a new built in release mechanism |
| US4891628A (en) * | 1988-12-29 | 1990-01-02 | Leonard Zuckerman | Environmental matter detection system |
| US5206806A (en) * | 1989-01-10 | 1993-04-27 | Gerardi Joseph J | Smart skin ice detection and de-icing system |
| US5195046A (en) * | 1989-01-10 | 1993-03-16 | Gerardi Joseph J | Method and apparatus for structural integrity monitoring |
| US5398547A (en) * | 1989-01-10 | 1995-03-21 | Innovative Dynamics, Inc. | Apparatus for measuring ice distribution profiles |
| US5005015A (en) * | 1989-08-07 | 1991-04-02 | General Electric Company | Ice detection system |
| US4996493A (en) * | 1989-08-21 | 1991-02-26 | Monat Seymour M | Instantaneous ice detection system |
| US5140135A (en) * | 1989-09-21 | 1992-08-18 | Rosemount Inc. | Adaptive ice detector circuit |
| US4991283A (en) * | 1989-11-27 | 1991-02-12 | Johnson Gary W | Sensor elements in multilayer ceramic tape structures |
| US5117687A (en) * | 1990-01-11 | 1992-06-02 | Gerardi Joseph J | Omnidirectional aerodynamic sensor |
| US5497100A (en) * | 1994-10-17 | 1996-03-05 | Hughes Aircraft Company | Surface condition sensing system |
| US5629485A (en) * | 1994-12-13 | 1997-05-13 | The B.F. Goodrich Company | Contaminant detection sytem |
| US6052056A (en) * | 1996-04-26 | 2000-04-18 | Icg Technologies, Llc | Substance detection system and method |
| US6560551B1 (en) | 2000-08-18 | 2003-05-06 | Rosemount Aerospace Inc. | Liquid water content measurement apparatus and method |
| US20040024538A1 (en) * | 2000-08-18 | 2004-02-05 | Rosemount Aerospace Inc. | Liquid water content measurement apparatus and method using rate of change of ice accretion |
| US6731225B2 (en) | 2002-02-14 | 2004-05-04 | Lockheed Martin Corporation | Method and apparatus for detecting and measuring thickness of ice on aircraft |
| FR2858595B1 (en) * | 2003-11-18 | 2005-10-14 | Auxitrol Sa | FROTH DETECTION ASSEMBLY FOR MOUNTING ON AIRCRAFT |
| US20050230553A1 (en) * | 2004-03-31 | 2005-10-20 | Rosemount Aerospace Inc. | Ice detector for improved ice detection at near freezing condition |
| US7104502B2 (en) * | 2004-03-31 | 2006-09-12 | Rosemount Aerospace Inc. | Ice detector for improved ice detection at near freezing condition |
| US7370525B1 (en) | 2006-10-31 | 2008-05-13 | Swan International Sensors Pty. Ltd. | Inflight ice detection system |
| US8217554B2 (en) * | 2008-05-28 | 2012-07-10 | Fbs, Inc. | Ultrasonic vibration system and method for removing/avoiding unwanted build-up on structures |
| GB0823121D0 (en) * | 2008-12-18 | 2009-01-28 | Penny & Giles Controls Ltd | Ice detection system |
| GB2475553A (en) * | 2009-11-24 | 2011-05-25 | Qinetiq Ltd | A sensor arrangement for determining the rate of ice formation |
| US9359081B2 (en) * | 2012-06-12 | 2016-06-07 | The Boeing Company | Icing condition detection system |
| US9587872B2 (en) * | 2012-12-03 | 2017-03-07 | Whirlpool Corporation | Refrigerator with thermoelectric device control process for an icemaker |
| DE102013015410A1 (en) * | 2013-09-17 | 2015-03-19 | Valeo Schalter Und Sensoren Gmbh | Method for detecting a blocked state of an ultrasonic sensor Ultrasonic sensor device and motor vehicle |
| US9612163B2 (en) | 2013-10-10 | 2017-04-04 | The Boeing Company | Methods and apparatus for detecting ice formation on aircraft |
| US9429680B2 (en) * | 2014-08-07 | 2016-08-30 | The Boeing Company | Ice crystal icing engine event probability estimation apparatus, system, and method |
| DE102015109151A1 (en) * | 2015-06-10 | 2016-12-15 | Valeo Schalter Und Sensoren Gmbh | Pollution detection device for detecting a dirt coating, driver assistance system, motor vehicle and method for detecting a dirt deposit |
| CN105644791B (en) * | 2015-08-31 | 2018-06-22 | 中国商用飞机有限责任公司 | Icing detection system and the aircraft with the anti-icing system |
| US10295489B2 (en) | 2016-09-12 | 2019-05-21 | Ecolab Usa Inc. | Deposit monitor |
| US10816285B2 (en) * | 2017-02-24 | 2020-10-27 | Ecolab Usa Inc. | Thermoelectric deposit monitor |
| US11953458B2 (en) | 2019-03-14 | 2024-04-09 | Ecolab Usa Inc. | Systems and methods utilizing sensor surface functionalization |
| CN110515140A (en) * | 2019-07-20 | 2019-11-29 | 安徽省艺凌模型设计有限公司 | A kind of Design of Mathematical Model method of hail prediction |
| CN111595386A (en) * | 2020-06-12 | 2020-08-28 | 中国民航大学 | Runway accumulated ice autonomous sensing device |
| CN112360722A (en) * | 2020-11-11 | 2021-02-12 | 青岛万宝压缩机有限公司 | Vibration reduction supporting device, compressor and refrigeration equipment |
| CN112572809B (en) * | 2020-12-17 | 2022-11-22 | 中国航空工业集团公司成都飞机设计研究所 | Hybrid icing detection method suitable for unmanned aerial vehicle platform |
| CN114674213A (en) * | 2021-12-09 | 2022-06-28 | 哈尔滨理工大学 | Road icing detection system based on piezoelectric resonant sensor and detection method thereof |
| WO2023113647A1 (en) * | 2021-12-16 | 2023-06-22 | Общество С Ограниченной Ответственностью "Микролаб" | Method for detecting icing using a thermoelectric sensor |
| CN114476081A (en) * | 2021-12-27 | 2022-05-13 | 武汉航空仪表有限责任公司 | Icing detector with stable performance |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB506843A (en) * | 1938-01-12 | 1939-06-06 | Rudolf Goldschmidt | Means for indicating ice formation |
| US3240054A (en) * | 1962-12-24 | 1966-03-15 | Gabb Special Products Inc | Ice detector |
| US3276254A (en) * | 1963-10-11 | 1966-10-04 | Rosemount Eng Co Ltd | Ice detection apparatus |
| US3270330A (en) * | 1963-11-04 | 1966-08-30 | Stanley Weinberg | Ice detecting apparatus |
| FR1397208A (en) * | 1963-12-20 | 1965-04-30 | Ice detector | |
| FR1410442A (en) * | 1964-08-12 | 1965-09-10 | Holley Carburetor Co | Icing condition detection device |
| US3341835A (en) * | 1964-11-05 | 1967-09-12 | Rosemount Eng Co Ltd | Ice detector |
| US3541540A (en) * | 1968-07-26 | 1970-11-17 | Rosemount Eng Co Ltd | Ice detectors |
| CH506850A (en) * | 1970-10-17 | 1971-04-30 | Meteolabor Ruppert & Buechler | Device for detecting the freezing of supercooled liquids |
| CA1090441A (en) * | 1976-11-10 | 1980-11-25 | Toshibumi Kamiyama | Frost detector |
| JPS5360293A (en) * | 1976-11-10 | 1978-05-30 | Matsushita Electric Ind Co Ltd | Frost detector |
| US4290299A (en) * | 1978-05-10 | 1981-09-22 | Pozin Mikhail A | Apparatus for continuous temperature measurement of the dew point of flue gases |
| SU762332A1 (en) * | 1979-02-19 | 1983-04-07 | E B Sinitsyn | Vibration-type ioe formation sensor |
| DE2928208C2 (en) * | 1979-07-12 | 1983-10-20 | Apparatebau Gauting Gmbh, 8035 Gauting | Process for detecting the risk of icing and ice warning sensor for carrying out this process |
| JPS5649299A (en) * | 1980-04-24 | 1981-05-02 | Iwasaki Kosei | Extrusion type note |
| US4470123A (en) * | 1982-01-05 | 1984-09-04 | Miami R & D Limited Partnership | Microwave ice accretion meter |
| US4461178A (en) * | 1982-04-02 | 1984-07-24 | The Charles Stark Draper Laboratory, Inc. | Ultrasonic aircraft ice detector using flexural waves |
| NL8202942A (en) * | 1982-07-21 | 1984-02-16 | Tno | Apparatus for determining icing or the like. |
-
1984
- 1984-02-27 CH CH940/84A patent/CH656015A5/en not_active IP Right Cessation
- 1984-05-07 US US06/607,526 patent/US4570881A/en not_active Expired - Lifetime
-
1985
- 1985-10-18 EP EP85810476A patent/EP0229858B1/en not_active Expired
- 1985-10-18 AT AT85810476T patent/ATE43731T1/en not_active IP Right Cessation
- 1985-10-18 DE DE8585810476T patent/DE3570777D1/en not_active Expired
- 1985-11-08 CA CA000494950A patent/CA1250926A/en not_active Expired
- 1985-11-25 SU SU3976888A patent/SU1521294A3/en active
- 1985-11-29 JP JP60267630A patent/JPS62132148A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| US4570881A (en) | 1986-02-18 |
| JPH0556831B2 (en) | 1993-08-20 |
| DE3570777D1 (en) | 1989-07-06 |
| CH656015A5 (en) | 1986-05-30 |
| ATE43731T1 (en) | 1989-06-15 |
| EP0229858B1 (en) | 1989-05-31 |
| JPS62132148A (en) | 1987-06-15 |
| EP0229858A1 (en) | 1987-07-29 |
| SU1521294A3 (en) | 1989-11-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1250926A (en) | Process for detecting the likelihood of ice formation, ice warning system for carrying out the process and utilization thereof | |
| US6560551B1 (en) | Liquid water content measurement apparatus and method | |
| US3986385A (en) | Apparatus for determining the freezing point of a liquid | |
| US9676485B2 (en) | Ice detection system and method | |
| RU2638064C2 (en) | Icing condition detecting system | |
| US3836846A (en) | Ice detection apparatus employing microwave reflectance | |
| US4327286A (en) | Method and apparatus for measuring the risk of ice formation | |
| JP2019059473A (en) | Methods and apparatus for detecting ice formation on aircraft | |
| JP2005145453A (en) | Ice detection assembly installed on airplane | |
| US20140260626A1 (en) | Apparatus and method for detecting obstructions in pipes or channels | |
| US4819480A (en) | Means and techniques useful in detecting ice on aircraft surfaces | |
| US5467944A (en) | Detector for indicating ice formation on the wing of an aircraft | |
| CN102407942A (en) | Ice formation condition detector | |
| US20040024538A1 (en) | Liquid water content measurement apparatus and method using rate of change of ice accretion | |
| Mughal et al. | State of the art review of atmospheric icing sensors | |
| US5187980A (en) | Method and apparatus for acoustic plate mode liquid-solid phase transition detection | |
| GB1249024A (en) | Improvements in or relating to apparatus for determining the freezing point of a liquid | |
| US5575440A (en) | Procedure and devices to determine the severity of icing conditions for an aircraft | |
| EP0723693B1 (en) | Device for indicating ice formation | |
| Li et al. | Detection of water-ice transition using a lead zirconate titanate/brass transducer | |
| US4891628A (en) | Environmental matter detection system | |
| RU162213U1 (en) | THERMOELECTRIC ICE SENSOR | |
| GB2067292A (en) | Ice warning indicator | |
| Weld et al. | Temperature measurement using surface skimming bulk waves | |
| White | Some Results on the Heat Transfer Within Resonant Cavities at Subsonic and Supersonic Mach Numbers |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |