Measuring device comprising a heating device

Abstract

The invention relates to a measuring device comprising heating means, intended to be arranged externally at the skin of a vehicle that can be moved in an atrocious climate environment under icy climate conditions, the measuring device corresponding to a body formed by a post carrying a tube closed at one end, the heating device is intended to be housed within the tube and comprises at least one heating wire wound within the body of the tube in a bridged coil winding defined by the presence of a bridge (P), corresponding to a portion of the heating wire, overlapping along the axis of the tube with a predetermined number of coils at the end of the coil winding located near the open end (12) of the tube, the overlapping coils are uniformly spaced at a predetermined pitch associated with the overlap region.

Description

Technical Field

[0001] The invention relates to a measuring device comprising a heating device, the measuring device being intended to be arranged on the skin of a vehicle outside the vehicle, the vehicle being able to move in a severe climatic environment associated with icing climatic conditions, the measuring device corresponding to a body formed by a column carrying a tube closed at one end, the heating device being intended to be housed inside the tube and comprising at least one heating wire wound inside the body of the tube.

[0002] The invention also relates to an aircraft comprising such a measuring device.

[0003] The invention relates to the field of heating of measuring devices intended to be arranged at the skin of a vehicle capable of moving in severe climatic environments associated with icing conditions, more particularly supercooled water icing conditions or crystal icing conditions. Background Art

[0004] Such equipment corresponds, for example, to civil or military aviation measurement equipment, which comprises flush parts or accessories emerging from the aircraft skin (i.e. it is located outside the aircraft). According to another example, such equipment is ground measurement equipment used in the military, scientific or meteorological fields, in particular for measurements in polar cold environments.

[0005] The attachment or flush component is, for example, a probe which can measure, in particular, various aerodynamic parameters of the airflow around the aircraft, such as the total pressure, static pressure, temperature or angle of incidence of the airflow, in particular near the aircraft skin. The total pressure in relation to the static pressure is used to determine the local velocity of the airflow near the probe and ultimately the airspeed and the altitude of the aircraft carrying the probe.

[0006] Other probes are used, for example, to measure the local angle of incidence of the airflow. The incidence probe may include movable appendages intended to orient themselves along the airflow axis around the probe. The orientation of the probe is used to determine the angle of incidence of the airflow.

[0007] Other incident probes can be equipped with fixed accessories that are equipped with multiple pressure measuring connections. The pressure difference measured between the pressure measuring connections is also used to determine the incident angle of the airflow around the probe.

[0008] During high altitude flights, the aircraft may encounter icing conditions.

[0009] Specifically, ice may form on the skin and accessories of the aircraft. The presence of ice is particularly problematic for pneumatic probes, through which the profile of the pneumatic probe may be changed and its pressure interface holes may be blocked. In other words, the presence of ice can distort the total pressure measurement of the probe and may render it inoperable in certain climatic conditions.

[0010] One solution to prevent ice formation is to heat the attachment. Currently, in most cases, heating is done by one or more heating wires wrapped around and embedded in the attachment, with heating being done by the Joule effect. For example, to preheat a total pressure probe, several hundred watts of power are required.

[0011] More precisely, this type of probe is formed by a rod supporting a tube called a pitot tube which is closed at one end, or alternatively, this type of probe is a pitot-static probe.

[0012] The probe is heated by one or more heating wires forming a heating resistor which is wound (i.e. formed in the form of a coil) in the probe body, i.e. in both the mast and the pitot tube 10. The pitot tube 10 is formed as a coil. Figure 1 As shown. This Pitot tube 10 has an open end 12 that allows the total atmospheric pressure to be measured. In addition, according to an embodiment, this tube optionally has an inner tube 14 located inside a total tube 16. The space 18 between the two tubes 14 and 16 is intended to insert a heating wire.

[0013] To make the heating wire, an electrical conductor (i.e. a core) consisting of an iron-nickel alloy is generally used, which is coated with an electrically insulating but not thermally insulating mineral insulator such as aluminum oxide or magnesium oxide. The insulator itself is coated with a nickel, nickel-chromium or chromium-nickel-incoat sheath enabling the wire to be brazed to the probe body. In other words, this heating wire corresponds to a metal-sheathed coaxial wire or, alternatively, to a shielded helical wire. The shaping (hereinafter also referred to as "winding") of the heating wire in the pitot tube 10, whether or not with an inner tube 12, is complex, the purpose of which is to provide a high-density heat evenly distributed along the wall of the tube 10, which is of very small dimensions (compared to the possibility of forming the heating wire), in particular as close as possible to its open end 12, which is most critical for anti-icing and de-icing, especially in supercooled water.

[0014] In other words, the manner in which the heating element, typically a metal sheathed coaxial heating wire, is shaped (ie, "wound") in the tube 10 of a pitot or pitot-static pressure probe affects the de-icing capability, particularly the sub-cooled water de-icing capability.

[0015] Figure 2 and Figure 3 Shows the current heating wire shaping scheme, Figure 2 and Figure 3 They represent the prior art upper pin winding and the back-and-forth winding as disclosed in patent EP 3 173 797 B1 respectively.

[0016] Figure 2 Based on the use of Figure 1 The upper pin winding of the pin 20 positioned along the radial axis of the inner tube 14 is shown to keep the figure simple. Figure 2The inner tube 14 is not shown in the figure. To form the upper pin winding, the heating wire is first bent in the middle to form a loop 22, and then the loop 22 is connected to the pin 20. Then, the "double wire" corresponding to the two branches of the loop 22 is simply wound on the pin 20 with a predetermined spacing and a predetermined length in a single thickness. Figure 1 On the inner tube 14 and the winding template shown in FIG. 1 , the winding (ie, coiling) is performed in a direction from the front facing the open end 12 of the pitot tube to the rear of the probe.

[0017] However, the pin-up winding is not optimal, mainly because of the ring 22 around the pin 20, the diameter of which forces the second two-wire coil 24 around which the heating wire is wound to move back. Due to the initial shaping of the ring 22, this offset creates gaps 26 between the coils of the heating wire, the surface area of ​​which is too large compared to the surface area directly heated. As a result, the heating wire density is lower than the density on the rest of the coil winding, and it is precisely at the open end 12 of the probe that the maximum power needs to be provided. This technical limitation is now compensated by ensuring that the entire coil winding has enough power to transfer the power forward by thermal conduction, but with the disadvantage that the nose of the pitot tube will overheat in ground or non-icing conditions. In addition, such gaps 26 may be conducive to corrosion, because the gaps may be filled with pollutants from the environment of the vehicle on which the measuring equipment including the tube 10 is arranged.

[0018] As an alternative, Figure 3 Another prior art solution corresponding to the back-and-forth winding disclosed in patent EP 3 173 797 B1 is shown. This back-and-forth winding consists in: the heating wire is in the form of a single wire (rather than as previously referred to in Figure 2 The double wire form for the upper pin winding described above) is placed on the template and then on the inner tube 14 (to keep the figure simple, Figure 3 The coil is wound over the probe (not shown) in a first "going" direction from the rear to the front 12 of the probe. Then, once the open end 12 is reached, winding continues over (i.e., coaxially) the initial coil winding in the same rotational direction but in a second "returning" direction from the front 12 to the rear of the probe, the second "returning" direction being opposite to the first "going" direction (i.e., reverse direction) from the rear to the front 12 of the probe.

[0019] In other words, this "back and forth" winding will inevitably result in the superposition of two layers 28 and 30 (thickness) of coil windings, such as Figure 3 As shown in the cross section below the dashed line, this reduces the efficiency of the heating wire in transferring heat by conduction. In fact, a central heat accumulation zone is formed between the two thicknesses of the wire, and since the wire is not in direct contact with the heat exchange zone, such entanglement may, under predetermined conditions, unfavorably lead to an increase in temperature, which may shorten the service life of the probe, wherein the increased temperature is higher than or very close to the melting point of the solder that keeps the wire assembled to the probe body.

[0020] In the non-butt-jointed portion of the double winding (i.e. according to two superimposed layers), the two thicknesses 28 and 30 do not overlap over the entire surface. However, it is difficult to ensure that the inner coil winding 30 of smaller diameter is well pressed against the wall and dissipates heat well. Therefore, this solution, although locally effective at the open end 12 of the tube 10, is not very effective in terms of overall efficiency and also leads to an increased risk of overheating on the ground.

[0021] In conclusion, Figure 3 This "back and forth" winding shown in the text proposes to reduce the gap 26 of the upper pin winding by a "double winding" corresponding to the coaxial superposition of the winding wires, but thereby creates a heat "overdensity" that may be harmful to the service life of the heating wire and, more importantly, does not allow the power required for deicing to be optimized by creating areas without direct heat exchange with the area to be heated.

[0022] Another prior art solution (not shown) is to use a portion of non-self-regulating bi-material heating wire on the first coil of the coil winding at the nose of the pitot tube to avoid loss of local heating capacity when conditions at the nose are severe, since in more traditional configurations the resistance of the heating wire decreases with temperature. However, the use of bi-material heating wire is expensive and presents risks in terms of reliability, particularly since the heating wire may break at the junction of the two materials forming the wire. Summary of the invention

[0023] Therefore, the purpose of the present invention is to overcome the disadvantages of the above-mentioned prior art by proposing a new solution for shaping the heating wire (i.e. a new type of winding) so as to integrate an optimal length of heating wire into the small space provided by the tube 10. This is done by seeking to position the heating wire with the highest density towards the front of the measuring device, i.e. near the open end 12 of the tube, so as to ensure that the maximum heat is provided to the nose of the measuring device, which is the part most susceptible to exposure to adverse outdoor climatic conditions, such as supercooled water freezing climatic conditions or crystal freezing climatic conditions.

[0024] To this end, the present invention relates to a measuring device comprising a heating device, the measuring device being intended to be arranged on the skin of a vehicle outside the vehicle, the vehicle being able to move in a harsh climatic environment associated with icing climatic conditions, the measuring device corresponding to a body formed by a column supporting a tube closed at one end, the heating device being intended to be housed inside the tube and comprising at least one heating wire wound inside the body of the tube, the coil winding of the heating wire being a bridged reciprocating coil winding defined by the presence of a bridging member, the bridging member being a portion of the heating wire, overlapping along the axis of the tube with a predetermined number of coils at the end of the coil winding located near the open end of the tube, the overlapping coils being evenly spaced at a predetermined spacing associated with the overlapping area.

[0025] This "bridge wrap" proposed according to the invention serves to increase the heating density at the front open end of the tube, which is a critical area for probe anti-icing or de-icing in supercooled water icing conditions and also on a smaller scale in crystallizing icing conditions.

[0026] In other words, the principle of the invention therefore consists in eliminating the initial forming ring of the pin and pin-up winding so that the winding coils can be arranged evenly spaced, while at the same time, in the zone of heat exchange with the zone to be heated, the return path of the wire is parallel to the axis of rotation of the winding in order to limit overlap and thus limit heat losses.

[0027] The bridge of the bridge winding according to the invention is used to obtain a "back and forth" winding almost with a single thickness, instead of with a double thickness as in the above-mentioned prior art related to the back and forth winding as disclosed in patent EP 3 173 797 B1. In fact, the only double thickness zone according to the invention is limited to the overlapping zone and its surface area is limited to the contact surface between the wire of the bridge and the coil overlapped (i.e. bridged) by the bridge, so that the heat generation associated with the reduced contact surface is negligible in terms of heat losses.

[0028] According to further advantageous aspects of the invention, the measuring device comprises one or more of the following features, taken alone or in all technically possible combinations:

[0029] - According to a first configuration, the bridge is located on the overlapping coils in the radial direction from the inside to the outside of the tube and is an external bridge;

[0030] - According to a second configuration, the bridge is located below the overlapping coils in the radial direction from the inside to the outside of the tube and is an internal bridge;

[0031] - each coil forming the coil winding is wound in the same direction and the winding diameter is approximately equal from one coil to another;

[0032] - the predetermined number of coils and / or the spacing of the coils is predetermined according to the heat density required to de-ice the open end of the tube and according to the predetermined vehicle mission;

[0033] - The coils overlapping the bridge are butt-jointed;

[0034] - the measuring device has a recess in the tube, the recess being configured to receive the bridge;

[0035] the measuring device is a pitot probe or a pitot-static probe, the tube corresponds to a pitot tube, the recess being provided at the total tube of the pitot tube to accommodate the external bridge according to the first configuration;

[0036] The measuring device is a pitot probe or a pitot-static probe, the tube corresponds to a pitot tube, the pitot tube also comprising an inner tube, the groove being formed at the inner tube of the pitot tube to accommodate the internal bridge according to the second configuration.

[0037] The invention also relates to an aircraft comprising a measuring device including a heating device as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] These characteristics and advantages of the invention will become more apparent on reading the following description given purely as a non-limiting example and with reference to the accompanying drawings, in which:

[0039] Figure 1 is a schematic cross-sectional view of a measuring device corresponding to a pitot pressure probe according to the present invention;

[0040] Figure 2 and Figure 3 Shown for heating Figure 1 The above-mentioned prior art solutions of the measuring device will not be described in detail below;

[0041] Figure 4 Schematic diagrams of two embodiments of bridge winding according to the present invention. DETAILED DESCRIPTION

[0042] In the following description, the expression "substantially equal to" refers to an equal relationship within plus or minus 10%, preferably within plus or minus 5%.

[0043] In the following the term "coil" refers to each turn of a heating wire forming a coil winding according to the invention.

[0044] Figure 4 are schematic diagrams of two embodiments 32 and 34 of a bridge-type winding of a heating device of a measuring device according to the invention, the measuring device being intended to be arranged outside a vehicle, at the skin of the vehicle, which vehicle can be moved in a severe climatic environment associated with icy climatic conditions, corresponding to a device supported by a support as described above Figure 1 The body is formed by a stem of a tube 10 shown in FIG. 1 , which is closed at one end.

[0045] Intended to be housed inside said tube 10 , the heating means comprise at least one heating wire wound inside the body of the tube 10 .

[0046] More specifically, for both embodiments (i.e., configurations) 32 and 34, the coil winding of the heating wire is a bridged reciprocating coil winding defined by the presence of a bridge member P, which corresponds to a portion of the heating wire, overlapping a predetermined number of coils at the end of the coil winding located near the open end 12 of the tube 10 along the axis 36 of the tube, and the overlapping coils are evenly spaced at a predetermined spacing associated with the overlap area.

[0047] It should also be noted that each end of the bridge is used to form a coil.

[0048] According to another additional optional aspect, the predetermined number of overlapping coils is strictly less than the total number of coils minus 1. According to another additional optional aspect, advantageously, in terms of thermal crowding, since hot spots are limited and the contact area between the heating wire and the tube 10 is maximized, for both embodiments (i.e., configurations) 32 and 34, each coil forming the coil winding is wound in the same direction (i.e., preferably from the front 12 to the rear, or alternatively from the rear to the front 12), and the winding diameter D is substantially equal from one coil to another.

[0049] Furthermore, the predetermined number of coils and / or the spacing of the coils is predetermined, for example four coils for the first configuration 32 and seven coils for the second configuration 34, depending on the heat density required for deicing the open end 12 of the tube 10 and according to the intended vehicle mission, in particular taking into account, for example, the geographical area of ​​the mission and the associated climate, and also the type of measurement equipment considered. According to another example, the overlapping coils are butt-jointed on the first centimeter of winding close to the open end 12, and there are ten butt-jointed coils.

[0050] The predetermined number of coils and / or the spacing of the coils is derived in particular from a thermal calculation depending on the required heating density (ie the amount of heat) near the open end 12 and for the measurement task in question, in order to prevent any measurement distortion due to ice formation.

[0051] According to a variant embodiment, the spacing is arranged so that the coils overlapping the bridge are butted, which serves to maximize the heating density close to the open end 12 of the tube 10, which is the most critical zone to be de-iced, in particular to prevent ice from falsifying the measurements made by the measuring device. For example, the overlapping coils are butted on the first centimetre of winding close to the open end 12.

[0052] According to a first configuration 32, the bridge P is an external bridge located at Figure 4 In the example, the butted coils are located on the outer side (ie the term "outer" is to be understood in the radial direction from the inside to the outside of the tube 10).

[0053] To obtain Figure 4The forming method of the first configuration 32 shown in the figure includes a first step of forming the butt joint portion of the heating wire coils, a second step of forming the external point P above these butt joint coils, and a third step of forming the non-butt joint portion of the heating wire.

[0054] According to an optional additional variant, when Figure 1 As shown, when the measuring device is a pitot probe or a pitot-static pressure probe, such a device has a groove in the tube 10, which is configured to accommodate the bridge P. It should be noted that Figure 4 In the figure, for the sake of illustration, the groove suitable for accommodating the external bridge member of the first configuration 32 is not shown, but such a groove would be formed in Figure 1 In the full tube 16 shown in FIG. 1 , to accommodate the external bridge piece P according to the first configuration 32 .

[0055] According to the second configuration 34, the bridge P is an internal bridge located at Figure 4 In the example, the coils are butted together (ie the term "interior" is to be understood in the radial direction from the inside to the outside of the tube 10).

[0056] According to an optional additional variant, when Figure 1 As shown, when the measuring device is a pitot probe or a pitot static pressure probe, the tube 10 corresponds to the pitot tube, and the pitot tube also includes the following Figure 1 and Figure 4 Such a device has a groove 38 in the tube 10 and at the inner tube 14, which groove 38 is configured to accommodate the bridge P. Figure 4 The forming method of the second configuration 34 shown in FIG. 1 includes a first step of preforming the internal bridge P, a second step of inserting the internal bridge P into the dedicated groove 38 of the inner tube 14, and a third step of forming the butt joint of the heating wire coil (as shown in FIG. Figure 4 ), followed by a fourth step of forming the non-jointed portion of the heating wire coil.

[0057] Regardless of configuration 32 or 34, according to Figure 4 In the illustrated embodiment, the bridge wrap includes both non-abutment portions and abutment portions that overlap the bridge.

[0058] Independently of the configuration 32 or 34 , according to an aspect not shown, this assembly is held in place by strong brazing, all cavities and intersections of the components being filled with brazing.

[0059] It should be noted that this bridge-wound heating assembly particularly takes advantage of changes in components near the coil winding. In fact, in the latest probe designs, such components, namely the inner tube 14 and the full tube 16, tend to be thicker and thicker, and the present invention takes advantage of this excess material thickness to accommodate other functions, such as the bridge winding proposed herein, and the optional accommodation groove proposed in addition to accommodating the winding bridge P, for the bridge winding configuration 34 with an internal bridge, which is suitable for integration (i.e., being accommodated) in this excess thickness of the inner tube 14, and for the bridge winding configuration 32 with an external bridge, which is suitable for integration (i.e., being accommodated) in the excess thickness of the full tube 16.

[0060] Independently of the configuration 32 or 34, this bridging allows to obtain a "back and forth" winding of the heating wire in an almost "single thickness".

[0061] The very small surface of the "double thickness" will certainly generate heat losses, but they are negligible, especially considering the fact that the bridge piece P is embedded in the groove 38 of the inner tube 14 or the full tube 16 (that is, the outer tube 16) to recover the heat of the heating wire bridge part for heating the area to be de-iced.

[0062] It should be noted that the windings at the ends may or may not have butted coils, depending on the heat density desired in the zone.

[0063] It will be appreciated by those skilled in the art that the present invention is not limited to the described embodiments nor to the specific examples of the specification, and that the above-described embodiments and modifications can be combined with one another to produce new embodiments of the present invention.

[0064] Therefore, the present invention is Figure 4 The bridge winding shown and proposed allows retention of Figure 3 All the advantages of the prior art "back and forth" winding shown above, but avoiding the congestion and efficiency loss associated with implementing double thickness throughout the "back and forth" winding process. In other words, the present invention can get rid of the double thickness that takes up more space and causes heat dissipation difficulties.

[0065] More precisely, the bridge winding proposed according to the invention allows the highest possible density of heating tape to be brought to the front of the measuring device without the occurrence of empty spaces associated with the pin-up winding according to the prior art.

[0066] The present invention can significantly improve the de-icing performance of a pitot probe or a pitot-static pressure probe, especially in the most critical area (the front end of such a pitot probe or a pitot-static pressure probe), in supercooled water, without affecting the service life of the heating wire due to overheating under less severe conditions, especially when flying on the ground or in high altitude dry air.

Claims

1. A measuring device, comprising a heating device, the measuring device being intended to be arranged outside a vehicle at the skin of the vehicle, the vehicle being movable in a severe climatic environment associated with icy climatic conditions, the measuring device corresponding to a body formed by a pole carrying a tube (10) closed at one end, the heating device being intended to be housed in the tube (10) and comprising at least one heating wire wound in the body of the tube, It is characterized in that The coil winding of the heating wire is a bridged reciprocating coil winding defined by the presence of a bridge (P), the bridge (P) corresponding to a portion of the heating wire, overlapping a predetermined number of coils at the end of the coil winding located near the open end (12) of the tube (10) along the axis (36) of the tube, and the overlapping coils are evenly spaced at a predetermined spacing associated with the overlap area.

2. The measuring device according to claim 1, wherein: In the first configuration (32), the bridge (P) is located on the overlapping coils in the radial direction from the inside to the outside of the tube (10) and is an external bridge.

3. The measuring device according to claim 1, wherein: According to a second configuration (34), the bridge (P) is located below the overlapping coils in the radial direction from the inside to the outside of the tube (10) and is an internal bridge.

4. A measuring device according to any one of the preceding claims, wherein: Each coil forming the coil winding is wound in the same direction, and the winding diameter (D) is approximately equal from one coil to another.

5. The measuring device according to any one of the preceding claims, wherein: The predetermined number of coils and / or the spacing between the coils is predetermined based on the heat density required to de-ice the open end (12) of the tube (10) and based on the intended vehicle mission.

6. The measuring device according to claim 5, wherein: The coils overlapping the bridge are butt-jointed.

7. A measuring device according to any one of the preceding claims, wherein: The measuring device has a recess (38) in the tube (10), the recess being configured to receive the bridge.

8. The measuring device according to claims 2 and 7, wherein: The measuring device is a pitot probe or a pitot-static pressure probe, the tube (10) corresponds to a pitot tube, and a groove is formed at the full tube (16) of the pitot tube (10) to accommodate an external bridge according to a first configuration (32).

9. The measuring device according to claims 3 and 7, wherein: The measuring device is a pitot probe or a pitot-static pressure probe, the tube (10) corresponds to a pitot tube, the pitot tube also includes an inner tube (14), and a groove is provided at the inner tube (14) of the pitot tube (10) to accommodate an internal bridge according to the second configuration (34).

10. An aircraft comprising a measuring device according to any one of claims 1 to 9, the measuring device comprising a heating device.

Images