WO1987003693A2

WO1987003693A2 - Process and sensor for measuring the direction and strength of fluid currents

Info

Publication number: WO1987003693A2
Application number: PCT/DE1986/000499
Authority: WO
Inventors: Roland Sommer
Original assignee: Roland Sommer
Priority date: 1985-12-09
Filing date: 1986-12-08
Publication date: 1987-06-18
Also published as: WO1987003693A3; EP0252100A1

Abstract

A process is used to determine the direction, the static and the dynamic pressure or the speed of a current on the basis of measured values of pressure or of differential pressures with the help of a new sensor having measuring chambers provided with rectangular or slot-shaped openings arranged along an arc of a circle or along the periphery of a circle. Under the influence of the current, dynamic pressure may build up in these chambers, which contain measuring instruments to determine the pressure in the measuring chamber and/or the differential pressure between two measuring chambers or pressure measuring ducts arranged in the back portion of each measuring chamber. These pressure measuring ducts leave the sensor separately or together with other pressure measuring ducts coming from other measuring chambers. The sensor is basically built in the form of a disk, and two perpendicular disks or sector-shaped disks arranged at the top of a body exposed to a current help to cover a wide solid angle.

Description

Probe and method for measuring fluid flows in terms of direction and strength

The invention relates to a probe for measuring fluid flows, and a method is specified with which fluid flows can be measured with respect to direction and strength, the probe being usable.

Many measuring devices for measuring fluid flows, in particular wind measuring devices, are already known. The areas of application for flowmeters include all areas in which currents play a role, e.g. meteorology, aviation, shipping, motor vehicles, wind tunnel measurements, etc. In particular in the case of aircraft, helicopters or other missiles, the direction of the air flow to and around the missile must be as well as the strength of the flow and thus the speed can be measured. Even if the measurement problems are different from one another in detail, the basic requirement for the flow measuring device is that this measuring device disturbs the flow to be measured as little as possible should. In addition, the presence of moving parts in a measuring device is undesirable since the moving parts usually cause particularly strong disturbances in the flow and are generally not free from inertia and hysteresis effects. So far, difficulties have arisen in this respect when the direction of a flow should be measured. On the other hand, if inertia and hysteresis effects were to be reduced in rotating parts of flowmeters, the bearings of the rotating parts had to be improved, which in turn either increased the weight of the measuring probe or made the measuring probe mechanically sensitive to shocks, shocks, vibrations etc. However, neither heavy nor mechanically sensitive measuring probes can be used in rough operation on ships or in aircraft.

The measuring probes used to date are based on the principles of the long-known pressure probe for measuring the static pressure, the Pitot tube, with which the sum of the dynamic pressure and static pressure is measured, and the Pitot tube according to Prandtl. This latter pitot tube is essentially a

Pitot tube in combination with a pressure probe required for measuring the static pressure and allows the determination of the dynamic pressure. Knowing the dynamic pressure, the speed, that is to say the journey in the case of aircraft, can be determined.

The conventional measuring devices, which are based on these principles, have various disadvantages, among other things the angle measuring range is relatively small in the case of pitot tubes. Good measuring accuracy can only be achieved with pitot tubes at blowing angles of up to 10 °. However, if an aircraft slides, for example, in strong air currents, so that a precise knowledge of the flow conditions would be particularly important, then the conventional pitot tubes often fail because they are blown too obliquely. Furthermore, the determination of the static pressure difficult because air movements can falsify a given height compensation, apart from the fact that such height compensations are expensive anyway.

Although there is a strong need, particularly in aeronautics, for a probe that does not experience these difficulties, there are similar problems in shipping and many other areas.

The object of the invention is to provide a probe for measuring the direction and / or the strength of a gaseous or liquid flow, which has no moving parts, can be aerodynamically designed so that it does not disturb the flow to be measured itself, and a wide one Has measuring range for the blowing angle / and with which either dynamic pressures can be measured directly without additionally having to determine the static pressure, or with which static pressures themselves can also be measured, if this is desired.

The invention is also intended to provide a method with which fluid flows can be measured with respect to direction and strength, it being possible in particular to use the probe according to the invention.

This object is achieved by a probe which contains two or more measuring chambers with rectangular or slit-shaped openings which (at least with their corner points) are arranged essentially along an arc or along the periphery of a circle, in which, under the influence of Flow in each case can form dynamic pressures, with measuring devices for determining the pressure in the measuring chamber and / or for determining differential pressures between two measuring chambers being provided in a rear region of each measuring chamber, or pressure measuring lines terminating separately or after being combined with other pressure measuring lines from other measuring chambers chambers are led out of the probe.

Particularly preferred embodiments of the probe according to the invention are specified in claims 2 to 32.

Particularly preferred is an embodiment of the probe according to the invention, which contains four measuring chambers, each of which is designed in the shape of a sector of a circle with acute angles of 45 and is arranged so as to abut one another so that they form a circular sector-shaped disk, and four further measuring chambers of the same type in the same arrangement are perpendicular to the first Four measuring chambers are arranged, the line of intersection running through the axes of symmetry of the two measuring chamber arrangements. Pressure measuring lines from the eight measuring chambers are led out towards the pointed parts of the measuring chambers and are located in a tube, which preferably serves as a holder for the probe.

In another preferred embodiment of the invention, the probe contains at least two measuring chambers which are open to the outside and have the same effective dynamic pressure measuring opening, which are axially symmetrical so that their measuring openings

tions in opposite directions, wherein measuring devices for determining the pressures in the measuring chambers and / or the differential pressure between the measuring chambers are provided in the rear parts of the measuring chambers.

In a preferred embodiment of the invention, four measuring chambers are provided, two of which are arranged axially symmetrically opposite one another and the other two likewise axially symmetrically opposite one another are arranged essentially at right angles to the first pair of measuring chambers, all four dynamic pressure measuring openings being equidistant from the common axis of symmetry .

As a result, the probe has two pairs of measuring chambers crossed at right angles, with which the flow is detected in directions that are perpendicular to one another. Although this rectangular arrangement for measuring the flow is a preferred embodiment, a different measurement characteristic can be achieved with an arrangement of two pairs of measuring chambers, which are arranged at a different angle, if this should be desired. It should be noted that a third pair of measuring chambers can also be provided at a further angle if other measuring characteristics are desired.

In a further preferred embodiment, each measuring chamber is subdivided into a plurality of subchambers, each of which has an outward-facing dynamic pressure measuring opening, and in each subchamber a measuring device is provided for determining the pressure and / or the differential pressure with respect to the subchamber axially symmetrically opposite it. It is particularly preferred that the probe has a plurality of - at least in the outer part - sector-shaped sub-chambers, which are arranged with their side faces abutting so that the end points of the side faces lie on a circle, and each form two or more sub-chambers a measuring chamber. From these subchambers, the pressure measuring lines are brought together to form a common pressure measuring line which is that of the common measuring chamber.

It is possible to assign individual subchambers to two adjacent measuring chambers at the same time, as a result of which the measuring chambers can partially overlap.

It should be noted that the number of sub-chambers has an influence on the measuring accuracy. The narrower the partial chambers and the more partial chambers thus form a measuring chamber, the more accurate the measurement result. This fact will be clarified later using an exemplary embodiment.

Good measurement results are obtained with the preferred embodiment of the probe according to the invention, which contains eight subchambers which are combined to form four measuring chambers, each with three subchambers. It is advantageous to design this probe in the form of a circular cylindrical disk, along the outer edge of which the measuring openings of the partial chambers or the measuring chambers are evenly distributed.

It should be noted, however, that flow-related modifications of the probe are also possible. For example, the top or bottom of the probe can be pulled out to a tip. However, only the effective dynamic pressure openings of the measuring chambers or partial chambers are decisive for the measurement results themselves. The method for measuring fluid flows with respect to direction and strength according to the invention is characterized in that the pressures are measured in at least two directions of a plane, which are set under the influence of the flow in measuring chambers with dynamic pressure measuring openings which are at fixed angles to one another. and the direction of the flow or dynamic pressure components are determined from differences in measured pressure values and / or the total pressure (dynamic pressure plus static pressure) is determined from sums of measured pressure values and / or from measured pressure values which are measured in measuring chambers which are so averted from the direction of flow, that the flow in them does not build up a dynamic pressure, the static pressure is determined and / or the flow velocity is determined by mathematical processing of pressure measurements or differences thereof.

Further advantageous embodiments of this method according to the invention are specified in claims 34 to 43.

The invention also provides a method for measuring the direction and / or the strength of a gaseous or liquid flow, which consists in that the dynamic pressure of the flow is measured in at least one measuring chamber system - which can consist of several subchambers - the second Chamber system with the same effective dynamic pressure opening is axially symmetrical, in which the pressure that arises is also measured as a reference pressure (which serves as a static reference pressure, for example), and the pressure difference determined or measured directly therefrom between the two chamber systems is obtained as a first reference variable , and in a third chamber system rotated by preferably 90 against both the first and the second chamber system with the same effective dynamic pressure opening, to which a fourth chamber system with the same effective dynamic pressure opening lies axially symmetrically, the dynamic pressure is measured and the difference to that in d em four th chamber system measured reference pressure (which serves approximately as a static pressure) is determined or measured directly, which provides a second reference variable, and determines the direction of the flow from the comparison of the two reference variables and / or the strength of the flow from the sum of the squares of the two Reference quantities is determined.

If all four chamber systems are each formed - at least in their outer part - in the shape of a sector of a circle and arranged so that their dynamic pressure openings lie in a plane on a circle, the first reference variable signal is a sine curve as a function of the incident angle and the second reference variable signal is dependent on the Approach angle in good approximation a cosine curve. The two reference quantity signals can be processed electronically according to the known standardization in an analog computer which analyzes the sine signal and the cosine signal according to size and sign in order to correctly determine the angle of attack. The analog computer preferably forms the arc tan value of the quotient from the sine signal and the cosine signal, which is a direct measure of the incident angle.

The two reference variable signals can also be electronically squared and summed individually, a measure of the strength of the flow being obtained. This value is independent of the direction of the flow. The invention can be better explained by means of exemplary embodiments. A description of exemplary embodiments follows with the aid of the attached drawings.

The drawings show:

FIG. 1 shows a section through a probe according to an embodiment of the invention,

FIG. 2 shows a schematic illustration of a section through a probe according to another embodiment of the invention,

FIG. 3 shows a schematic view of a section through a probe in accordance with yet another embodiment of the invention,

FIG. 4 shows a schematic representation of a section through a probe according to yet another embodiment of the invention,

FIG. 5 shows a perspective view of the essential components of a probe according to the embodiment shown in FIG. 3,

FIG. 6 shows a perspective view of a probe according to the embodiment shown in FIGS. 3 and 5,

FIG. 7 shows a schematic illustration to explain yet another embodiment of a probe according to the invention,

8 shows measured values as a function of the blowing angle, which are obtained with the probe according to the embodiment in FIG. 7,

FIG. 9 shows a schematic illustration of a different measuring chamber arrangement than that shown in FIG. 7,

FIG. 10 measurement values obtained with this measuring chamber arrangement, FIG. 11 shows a measuring chamber arrangement of a probe according to another embodiment of the invention;

Figure 12 is a schematic representation of the probe shown in Figure 11 with pressure measuring devices;

13 shows the profile a) of the pressure difference between the two measuring chambers shown in FIG. 12, which supply a sine signal, b) of the pressure difference between the two other measuring chambers shown in FIG. 12, which supply a cosine signal, and c) of the squared and summed pressure difference signals in Dependence on the inflow angle;

FIG. 14 measured values in comparison to values theoretically determined by simulation in accordance with the sine curve or cosine curve in FIGS. 13 and

Figure 15 is a block diagram of a 360 ° probe for wind measurement.

Figure 1 shows the front part of a probe according to the invention in section. Two measuring chambers 1 and 2 with rectangular slot openings are each in. Floor plan shaped like a sector of a circle and are arranged next to each other and with one side wall abutting each other so that their openings lie along an arc. The sectional view shown in Figure 1 corresponds to a section through the measuring chambers 1 and 2 along the longitudinal direction of the slot-shaped openings. The thickness of the measuring chambers, i.e. the expansion perpendicular to the plane of the paper is the same everywhere in the front part of the measuring chambers. The fluid flow impinging on the probe from the front thus meets rectangular or slit-shaped openings.

For manufacturing reasons in particular, it will make sense to choose the thickness of the measuring chambers the same everywhere over their entire area, so that the measuring chambers are disk-shaped hollow chambers.

Measuring devices for determining the pressure in the measuring chamber and / or for determining the differential pressure between the measuring chambers 1 and 2 are provided in the rear region of the measuring chambers 1 and 2. In the example shown in FIG. 1, pressure measuring lines 11, 13 and 12, 14 are shown only schematically, which end in a rear area corresponding to measuring chamber 1 or 2 and are led out of the measuring chamber to the rear. Via the measuring lines 11 and 12, the pressures p ₁ which arise under the influence of the impinging flow, in measuring chamber 1 and p ₂ in measuring chamber 2, are measured directly, while the pressure measuring lines 13 and 14 are brought together to form a connecting line 15 with which the Pressures p ₁ and p ₂ resulting pressure is measured. This resulting pressure corresponds to an addition of the pressures p ₁ and p ₂ at a blowing angle of ± 45 °. From the pressures p ₁ and p ₂ , which are tapped via the pressure measuring lines 11 and 12, the difference is formed, which is a continuous function depending on the blowing angle α. More precisely, this pressure difference is a measure of the component of the blowing angle, which is created by projecting the blowing direction onto the plane of the measuring chambers. In practice (eg when flying on airplanes) this component would correspond to the vertical or horizontal component of the incident angle, which depends on the position of the measuring probe.

The probe shown in FIG. 1 can thus be used to determine the total pressure and the blowing angle for flows which strike from the front in a range of ± 45 °.

In a front area, i.e. near the periphery of the circular arc, partitions 21 and 22 are provided which extend a small distance into the interior of the measuring chambers. Such partitions increase the measuring accuracy. The more partition walls are provided within a measuring chamber, the better the measuring accuracy is increased. On the other hand, the provision of too many partition walls can lead to easier soiling of the measuring chamber opening, which then on the other hand falsifies the measurement. In practice, the specialist will find the right number of partitions through testing, depending on the application.

Figure 2 shows a schematic view of a further embodiment of the probe according to the invention in section. The angle measuring range in which the probe can be used is indicated by arrows and is ± 45 °. The fluid flow is referred to as "WIND" in the figure. In the embodiment shown, the probe is a circular disk, from which the measuring chambers 3, 4, 5 and 6 occupy two sector sections. The measuring chambers 3, 4, 5 and 6 are themselves designed in the shape of a sector of a circle and have an acute angle of 45. The chambers 3 and 4 are diametrically opposite to the chambers 5 and 6 and indeed symmetrically to the measuring range of the blowing angle. In the measuring chamber 3, the pressure is p _1, in the measuring chamber 4, the pressure p _2, p in the measuring chamber 5, the pressure in the measuring chamber ₃ and p 6 the pressure. ₄ The pressure difference p ₁ , p ₂ is established in a connecting line 16 by a pressure-related connection of the chambers 3 and 4, while the pressure difference p ₃ , p _{4 is} established in a connecting line 17 by pressure-connecting the chambers 5 and 6. The connecting lines 16 and 17 are brought together in a pressure chamber, in which the pressure difference from the two pressure differences p ₁ , p ₂ and p ₃ , p ₄ is accordingly established. A connecting line 18 opens into this pressure chamber, from which the resulting pressure can be tapped.

From the theory of the flows around a cylinder or a circle it follows that the pressure tapped in the connecting line 18 is the prevailing static

Pressure P _stat is when the blowing angle is ≤ ± 45 °.

In this embodiment of the probe according to the invention, the static pressure can therefore be measured, which plays an essential role as a barometric pressure when flying.

Figure 3 shows yet another embodiment of the probe according to the invention in section. Four sector-shaped measuring chambers 3, 2, 1 and 5, each with an acute angle of 45 °, are arranged so that their slot-like openings lie on a semicircle. The measuring range of this probe includes a blowing angle of ± 45 ° with respect to the axis of symmetry. At any angle within the measuring range of ± 45 °, the effective dynamic pressure area for the flow (ie the projection of the area of the chamber openings) is: Circular diameter of the probe multiplied by the disk thickness of the measuring chamber height. This effective storage area is therefore the same for all inflow angles within the measuring range.

Since the effective stowage area of the probe thus always remains constant within the permissible blowing angle of ± 45 °, the partial pressures p ₁ measured in the segment-shaped or circular sector-shaped measuring chambers of 45 ° are obtained in measuring chamber 3, p ₂ in measuring chamber 2, p ₃ in measuring chamber 1 and p ₄ in measuring chamber 5 a constant dynamic pressure as a function of the respective blowing strength of the flow. The total pressure P _tot is therefore equal to the sum of the four pressures measured in the measuring chambers 3, 2, 1 and 5.

P _tot = P ₁ + P ₂ + _P3 + P ₄ .

With the probe according to FIG. 3, it is thus possible to measure the total pressure, which is the sum of the dynamic pressure and the static pressure, within a large inflow angle.

By measuring the differential pressure between the measuring chambers 2 and 3 on the one hand and 1 and 5 on the other hand, ie the measuring chamber pairs which are mirror images of each other with respect to the axis of symmetry, it is possible to determine the exact blowing angle α, as was described in connection with FIG. 1. With the probe shown in FIG. 3, however, the dynamic pressure can also be measured directly using another method, in the following way:

If the flow strikes the probe from the front, it generates pressures in the measuring chambers ₃ , ₂ , ₁ and 5, which have been designated p ₁ , p ₂ , p ₃ and p ₄ in the drawing. Each of these partial pressures is made up of static pressure and a dynamic pressure component. If the blowing angle is greater than zero, ie the flow does not coincide with the axis of symmetry of the probe, every dynamic pressure component that is present in p ₁ , p ₂ , p ₃ or p ₄ other than the static pressure is different. Since the measuring range of the probe for this type of measurement is ± 22.5 ° to the axis of symmetry of the probe - as will be explained in more detail below - the pressure p _{2 is} greater than the pressure p ₁ and the pressure pi is greater than p ₄ . By forming the difference p ₂ minus p ₁ or p ₃ minus p ₄ , a pressure difference is obtained which corresponds to the pressure difference of the dynamic pressure components in the chambers 2 and 3. The static pressure stands out during subtraction. In the same way, the difference p ₃ minus p ₄ provides the difference of the dynamic pressure components of the measuring chambers 1 and 5.

If the differences of the _dynamic pressure _components p ₁ minus p ₂ and p ₃ minus p ₄ obtained in the manner described above are now added, a _dynamic pressure _component p _{jam is} obtained which corresponds to the total _dynamic pressure which is in the chambers _3, _2, ₁ and 5 is generated is proportional.

If the measuring range is now limited to the blowing angle of ± 22.5 ° to the axis of symmetry of the probe, this is the total dynamic pressure component created by summation p _accumulation over the entire measuring range of the probe is proportional to the dynamic pressure, which is the sum of the dynamic pressure components of the pressures p ₁ , p ₂ , p ₃ and p ₄ . The limitation to the blowing angle of ± 22.5 ° to the axis of symmetry of the probe is necessary because at larger angles in one of the chambers 3 or 5 no back pressure is built up, so that the corresponding difference p ₂ minus p ₁ or p ₃ minus p _{4 would} only contain the dynamic pressure component of the pressure p ₂ or p ₃ .

On the other hand, it is shown that with a restriction to the blowing angle of ± 22.5 °, the dynamic pressure can be measured with this embodiment of the probe without the static pressure being additionally measured. This also allows the speed of the flow (the "ride" on airplanes) to be determined. This gives the very important advantage that no more height errors occur or have to be corrected.

Figure 4 shows a further improved embodiment of the probe according to the invention in section. In this probe, six measuring chambers 1, 2, 3, 4, 5 and 6 are provided, each of which is in the form of a sector of a circle with an acute angle of 45 °, and these measuring chambers each abut the adjacent measuring chamber with their side edges, so that the whole Probe covers a sector sector of 270 °. In the rear part of the probe, which is not used as a measuring chamber, pressure lines are led out of the measuring chambers. These pressure lines run in a tube that also serves as a holder for the probe.

The measuring range of the fluid flow, here again referred to as "WIND", is ± 45 ° to the axis of symmetry of the probe. Under the influence of the flow, the corresponding pressure p ₁ , p ₂ , p ₃ , p ₄ , p ₅ and P ₆ prevail in the chambers ₁ , ₂ , ₃ , ₄ , ₅ and _6, respectively. The static pressure P _stat can be determined via the measuring chamber pairs 3, 4 and 5, 6 in the same way as has been described in connection with FIG. For this purpose, the differential pressure of the measuring chambers 3 and 4 is merged via the pressure connection line 16 with the differential pressure between the measuring chambers 5 and 6 via the pressure connection line 17, where the differential pressure which arises can be tapped off as a static pressure via the connection line 18.

The measuring chambers 1 and 2 serve on the one hand as a storage chamber (pitot tube) and are connected to one another in terms of pressure for this purpose. The connecting line 15 is also led out of the back of the probe. In addition, the measuring chambers 1 and 2 serve to determine the inflow angle α, more precisely, the component of the inflow angle in the plane of the measuring chambers. For this purpose, the pressure lines 11 from the measuring chamber 1 and 12 are led out of the measuring chamber 2 directly from the measuring chambers in order to be able to determine the pressure difference, as has been described in connection with FIG. 1.

It is of course also possible to determine the total pressure as the sum of the pressures p ₁ , p ₂ , p ₃ and p ₅ , as has been described in connection with FIG. 3.

In any case, this embodiment of the probe enables the total pressure, the dynamic pressure, the static pressure and the inflow angle α to be determined simultaneously with the same probe. The measuring range of the probe with an incident angle of ± 45 ° is extremely large compared to the prior art.

It should be noted that by combining the two pressures measured at the same location, namely dynamic pressure and static pressure, it is possible for the first time to measure the actual flow conditions at a specific location. In aircraft, for example, the speed, the ambient pressure and the direction of flow can be determined at the same time.

The previously described embodiments of the probe according to the invention each comprise only sector-shaped measuring chambers which lie in one plane. With probes of this type, as has already been mentioned several times, only the conditions in one plane, for example the horizontal or vertical plane, can be determined. The for the A particularly advantageous embodiment of the probe according to the invention therefore has, in addition to the disk-shaped measuring chamber arrangement of the first level, a second disk-shaped measuring chamber arrangement which is arranged at right angles to the first measuring chamber arrangement, the line of intersection running through the axes of symmetry of the two disk-shaped measuring chamber arrangements. In this way it is possible to carry out the same measurements which can be carried out in one plane as described, in addition in the plane perpendicular thereto, so that the entire solid angle of ± 45 ° to the axis of symmetry of the probe is detected by the measurement becomes.

A probe of this type for measurement in the spatial blowing angle range is shown schematically in FIG. 5. This probe shown there has an arrangement of four measuring chambers 1, 2, 3 and 5 in the horizontal and in the vertical direction, as shown in section in FIG. 3. The pressures p ₁ , p ₂ , p ₃ and p ₄ indicated in FIG. 5 prevail in the measuring chambers 3, 2, 1 and 5, respectively, according to the numbering in FIG. 3.

By combining these two measuring chamber arrangements, which are perpendicular to each other along their axes of symmetry, a probe is obtained which delivers a constant dynamic pressure as a measured variable both in the vertical and in the horizontal plane within ± 45 ° of the axis of symmetry.

By measuring the differential pressures between the pairs of measuring chambers, which lie on both sides of the axis of symmetry and abut each other on the axis of symmetry, it is possible to determine the blowing angle both within the two planes and consequently in the corresponding space to determine the angular range.

In an analogous manner, a spatially measuring probe can be obtained in that six measuring chambers 1, 2, 3, 4, 5 and 6, which are designed in the shape of a circular sector and are arranged so as to abut one another, as shown in FIG. 4, with six more measuring chambers of the same type are combined in the same arrangement at right angles to one another, the cutting line running through the axes of symmetry of the two circular sector-shaped disks. The construction corresponds to that of the probe which is shown in FIG. 5, the front part of the probe being formed by a larger spherical cap.

Such spatially measuring probes are used in a variety of ways in flight technology. On the one hand, they can be used as pitot tubes like a Pitot tube for measuring aircraft speed. Furthermore, the slip of an aircraft, which plays a strong role in side gliding, can be detected with such probes. It even becomes possible to measure the angle at which an aircraft moves in a slip-like manner, for which purpose the pressure difference measurement p ₂ , p ₁ , is carried out, and also to measure travel at the same time, which is possible by determining the dynamic pressure.

It is also possible to measure the angle of attack precisely. In this way the stall point can be detected when the current threatens to break off and a stall warning can be given.

By combining measuring pressures p ₁ to p ₆ in the two mutually perpendicular planes and the measurement the resulting differential pressures make it possible to record circular and swirled flows within a given flow direction. The solid angle range of ± 45 ° that can be detected is extremely high.

Basically, it should be noted that the probe can be held in a fluid flow to be measured, but that it can also be attached to missiles and is thus moved through fluid media. This does not change the measuring principle.

However, a very important field of application of the probe according to the invention lies primarily in its. Use as a measuring probe on missiles: It can be used to measure travel without the need to measure static pressure or reference pressure. Until now, it was necessary to perform barometric compensation for every measurement of the dynamic pressure in order to determine the travel (i.e. the speed V). Good devices often have compensation from the altimeter, but an error caused by air currents is always possible and likely.

The blowing angle or the angle of the missile stimulating the flow can be measured simply by pressure differences. The measurement of travel (v) and angle (α) is possible in two planes over a large measuring angle. While in the Prandtl pitot tube currently used for aircraft for the measurement of dynamic pressure and static pressure for travel measurement via dynamic pressure, taking into account the static pressure, a measuring angle range of ± 15 ° was available, the probe according to the invention offers a measuring angle range of ± 45 °. In any case, jam nozzles only measure accurately in angular ranges of ± 10 ° high error sources at larger measuring angles. The probe according to the invention can also be used as a measuring probe for barometric or static pressure, ie replace a conventional pressure probe for measuring the static pressure from a rounded tube with ring slots (either the configuration shown in FIG. 2 is used for this, or the pressure in one or more measuring chambers, which are located at the rear end of the measuring probe, opposite to the flow, which is essentially equal to the static pressure).

In summary, the main application of the probe according to the invention results as an angle and travel meter for aircraft and also for ships and possibly land vehicles.

Figure 6 shows a perspective view of a probe according to the invention for spatial measurement, which is housed in a housing with low flow resistance. It has a spherical cap shape on the front.

If, however, more chambers are to be used for the measurement, as corresponds, for example, to the probe according to FIG. 4 or if the last two chambers not used in FIG. 4 are also to be used for the measurement of the static pressure, the shape of the housing of the probe must be used be modified accordingly. In the case of a circular disk-shaped probe, the holder of the probe must of course be led out of the measuring plane. It is clear to the person skilled in the art that care must be taken to ensure that the flow resistance of the probe against the flow to be measured is low. Figure 7 finally shows schematically the cross section of a circular disk-shaped probe with several circular sector-shaped measuring chambers 1, 3, 5 and 7, which are not butted but arranged with gaps so that their measuring openings are arranged along the periphery of a circle. Under the influence of a flow of compressed forms in this probe in the measuring chamber 1 p _1, in the measuring chamber 3, the pressure p _2, p in the measuring chamber 5, the pressure in the measuring chamber ₃ and 7, the pressure P ₄ from. If the blowing angle changes by 360 °, the pressure differences p ₃ minus p ₁ and _p4 minus P _{2 change} continuously and thus allow a conclusion to be drawn about the blowing angle during measurement.

FIG. 8 shows curves of sizes p ₃ minus p ₁ obtained by computer simulation; p ₄ minus p ₂ and the sum of the squares of these quantities. In the present case the curves are pure sine or cosine curves, consequently the third curve is a straight line.

The example of FIGS. 7 and 8 is intended to show that the design of the probe according to the invention is not only limited to the embodiments described in FIGS. 1 to 4, but that the measuring chamber arrangement can be modified in accordance with the measuring purpose. In this way, the measuring range of the blowing angle, the pressure conditions of interest, etc. can be changed, or the probe can be modified if certain blowing angle ranges are blocked or disturbed.

Although in all exemplary embodiments the measuring chambers have a plan of a circular sector with an acute angle of 45 °, it is expressly noted that this Principle of operation of the probe is not limited to this shape of the measuring chambers. Rather, measuring chambers can also be used whose front part (ie in the region of the periphery of the circular arc) is sector-shaped, the sector section corresponding to an angle other than 45 °.

In addition, the rectangular or slit-shaped openings of the measuring chambers can deviate from the circular arc shape, e.g. be straight, but the corner points of the measuring chamber openings lie on a circular arc, so that the sector configuration remains "essentially" preserved.

FIG. 9 schematically shows the cross section of a circular disk-shaped probe with a plurality of measuring chamber-shaped measuring chambers 1, 3 and 5, which are not butted but are arranged with gaps such that their measuring openings are arranged along the periphery of a circle. Under the influence of a flow of compressed forms in this probe in the measuring chamber 1 p _1, in the measuring chamber 3, the pressure p ₂ and in the measuring chamber 5, the pressure p ₃ of. If the direction of flow coincides with the axis of symmetry of the probe, the pressure p ₂ in the measuring chamber 3 has its maximum. In this case the pressure difference p ₃ - p ₁ is zero.

The change in the pressure p ₂ in the measuring chamber 3 as a function of the blowing angle α has a sinusoidal shape, as can be seen from FIG. 10. The course of the pressure difference is also shown in FIG. p ₃ - p ₁ depending on the angle of attack. These curves were also obtained through computer simulation, The third curve shows the course of the size

This size is proportional to the velocity v of the flow relative to the probe. This type of determination of the speed v can be carried out within a range of 180, as can be seen from FIG. 10. In Figure 10, this value is constant over the range α = 90 ° to 270 °.

With a probe according to this embodiment, the speed (or the "run") can thus be determined without the static pressure having to be determined in any other way.

The measuring chamber arrangement of a probe according to the invention shown in FIG. 11 consists of eight partial chambers 1, 2, 3, 4, 5, 6, 7 and 8, of which the partial chambers 1, 2 and 3 form the measuring chamber 31, the partial chambers 3, 4 and 5 form the measuring chamber 32, the partial chambers 5, 6 and 7 form the measuring chamber 33 and the partial chambers 7, 8 and 1 form the measuring chamber 34. The measuring chamber 31 lies axially symmetrically opposite the measuring chamber 33 assigned to it and forms with it a first pair of measuring chambers, to which the pair of measuring chambers formed from the measuring chambers 32 and 34 is arranged at right angles. The partial chambers are each sector-shaped and abut one another with their side faces in such a way that the end points 43 of the equally long side faces lie on a circle.

In the illustrated embodiment, each sub-chamber has an outer opening which is part of a cylinder wall. It should be noted that the opening could also be designed as a straight connection between the end points 43 (the probe plan being a polygon), since the only thing that is important for the measurement is the effective chamber opening, which determines the dynamic pressure caused by the flow to be measured. Measuring devices 44 are provided in a rear part of each partial chamber so that the dynamic pressure measurement is influenced as little as possible. For example, they can each consist of an open tube or an open pressure line, the measuring opening of which is located in the partial chamber, while the other end is guided to a measuring device located outside the probe. However, the pressure in the sub-chamber which arises under the influence of the flow can also be measured directly in the sub-chamber and passed out of the probe as an electrical signal and further processed there electronically.

As shown in FIG. 12, open pressure lines are provided as measuring devices and are led out of the partial chambers. The pressure lines of the subchambers 1, 2 and 3 are brought together to form a common pressure line 45 which is connected via a measuring device for differential pressures 46 to a pressure line 47, to which the pressure pipes from the subchambers 5, 6 and 7 are brought together. In this way, the measuring chamber 31 is connected in terms of pressure to the measuring chamber 33 via the pressure line 45, the measuring device 46 and the pressure line 47.

If, as shown in FIG. 12, a flow strikes the probe so that a back pressure builds up in the subchambers of the measuring chamber 33, then this back pressure can be measured in the measuring device 46 as a pressure difference compared to that from the subchambers 1, 2 and 3 existing measuring chamber 31, in which the reference pressure prevails, can be determined. In the example shown, the measuring device 46 consists of a combination of two subminiature NTC resistors, ie a resistance element with negative temperature characteristics, which are arranged one behind the other in the direction of flow. If the dynamic pressure of the pressure line 47 balances itself out via the resistor combination, the flow against the first resistor is cooled more than the other. The resistors are parts of a bridge circuit in which the NTC resistors are used for voltage division, so that the pressure difference between the two measuring chambers 33 and 31 is determined from the changes in resistance.

If the probe shown in FIG. 12 is rotated about its axis of symmetry against the flow by the angle α, the bridge circuit (referred to in FIG. 12 as "bridge amplifier") delivers a sinusoidal curve as a function of the incident angle. If the pressure difference between the measuring chambers 32 and 34, which are formed from the subchambers 2, 3 and 4 or 7, 8 and 1, is measured at the same time in an analogous manner, the pressure difference signal has a cosine curve as a function of the inflow angle α.

This sine curve and this cosine curve are shown in FIG. These curves were theoretically obtained by simulation of the dynamic pressure to be expected on the basis of geometric considerations of the effective dynamic pressure measuring openings, ie the effective effective openings of the measuring openings 20, 20 ', 20 ", etc. FIG. 14 shows a comparison of this kind theoretically Simulation of determined values with actually measured values practically measured on a model. It can already be seen from FIG. 14 that the measured values can be in good agreement with the theoretically expected values.

The model on which the measured values of FIG. 14 were measured was a probe with eight subchambers, as shown in FIG. 11. A higher accuracy and better adjustment to the sinusoidal or cosine-shaped course can be achieved if the number of subchambers is increased.

The sensitivity, however, depends on the opening angle of the measuring chamber. If the measuring chambers are subdivided into several subchambers, this means that combining more subchambers, which means an increase in the effective dynamic pressure measuring area, leads to an increase in sensitivity, while combining fewer subchambers to one measuring chamber, which corresponds to a reduction in the effective dynamic pressure measuring area, leads to a reduction in sensitivity.

The choice of the total number of subchambers, the choice of how many subchambers are combined to form a measuring chamber, the choice of the opening angle of a measuring chamber, the shape of the dynamic pressure measuring opening, the influence of edge effects of the dynamic pressure measuring opening etc. are determined in practice by the person skilled in the art.

FIG. 15 shows a block diagram for a probe according to the invention, which measures wind flows by direction and strength over 360 °. This probe can, for example, also be the probe shown in FIG. 4, completed by two chambers to form a circle, in which the holder is made correspondingly thin or the pressure lines out of the plane of the disc protruding atus of the probe are led out.

The measuring chamber arrangement, the actual sensor, is located in the wind flow. The pressure measuring lines of the subchambers of each measuring chamber are led out of the sensor as the only pressure line, as shown in FIG. 12 with the reference symbols 45 and 47. The pressure difference between two opposite measuring chambers supplies the sine signal, while the pressure difference between the other two opposite measuring chambers and arranged at right angles to the first pair of measuring chambers provides a cosine signal. The sine signal is input into an operational amplifier sine OP and the cosine signal into an operational amplifier cosine OP. The outputs of these operational amplifiers are connected to the inputs of an analog computer which generates the respective arc tan value of the quotient from the sine signal and the cosine signal and outputs it to a wind direction display device such as a compass. The inflow angle α can be read directly on the wind direction indicator.

The sine signal and the cosine signal are further given to squaring circuits "Sinus ² " and "Cosinus ² ", each of which squares the signals, and the outputs of these two squaring circuits are summed in a power amplifier. The resulting output signal is a measure of the wind strength and is independent of the direction. The course of this signal as a function of the incident angle is shown as the third curve in FIG. 13 (curve c).

A flow measuring probe, which analyzes and measures flows over 360 ° according to direction and strength, as shown in FIG. 15, has many possible uses in shipping, aviation, etc., as can easily be seen from the properties described.

INTERNATIONAL APPLICATION PUBLISHED AFTER THE INTERNATIONAL COOPERATION AGREEMENT IN THE PATENT AREA (PCT)

(51) International patent classification. (11) International publication number: WO 87/03 G01P 5/14 A3 (43) Internationales

Release DATE: June 18, 1987 (June 18

(21) International file number: PCT / DE86 / 00499 (81) Destination countries: AT (European patent), BE European patent), CH (European patent),

(22) International filing date: (European patent), FR (European patent),

December 8, 1986 (December 8, 1986) (European patent), IT (European patent), LU (European patent), NL (European patent SE (European patent).

(31) Priority reference number: P 35 43 431.7 P 36 04 335.4 Published

With international research report.

(32) Priority dates: December 9, 1985 (Dec. 9, 1985) February 12, 1986 (Feb. 12, 1986) Approved for expiry of claims changes

Deadline. Publication will be repeated if change

(33) Priority country: DE arrive.

(88) Publication date of international searches

(71) (72) Applicant and inventor: SOMMER, Roland [DE / ^Judgment: 16 July 1987 (16.07. DE]; Kronthaler Weg 15, D-6231 Schwalbach am Taunus (DE).

(74) Lawyer: SCHÜLER, Helga; Kaiserstrasse 69, D-6000 Frankfurt / Main 1 (DE).

(54) Title: PROCESS AND SENSOR FOR MEASURING THE DIRECT.ION AND STRENGTH OF FLUID C RENTS

(54) Name: PROBE AND METHOD FOR MEASURING FLUID FLOWS REGARDING DIRECTION AND STRENGTH

(57) Abstract

A process is used to determine the direction, the static and the dynamic pressure or the speed of a current on the basis of measured values of pressure or of differential presures with the help of a new sensor having measuring chambers provided with rectangular or slot -shaped openings arranged along an arc of a circle or along the periphery of a circle. Under the influence of the current, dynamic pressure may build up in these chambers, which contain measuring instruments to determine the pressure in the measuring chamber and / or the differential pressure between two measuring chambers or pressure measuring ducts arranged in the back portion of each measuring chamber. These pressure measuring ducts leave the sensor separately or together with other pressure measuring ducts coming from other measuring chambers. The sensor is basically built in the form of a disk, and two perpendicular disks or sector-shaped disks arranged at the top of a body exposed to a current help to cover a wide solid angle.

(57) Summary

Method for determining the direction of a flow, the static pressure, the dynamic pressure or the speed of the flow from measured pressure values or differences from measured pressure values by means of a new probe with measuring chambers with rectangular or slit-shaped openings which essentially lie along an arc or along the periphery of a circle are arranged in which under the influence of the stagnation in each case backpressures can form and the measuring devices contain a rear region of each measuring chamber for determining the pressure in the measuring chamber and / or for determining differential pressures between two measuring chambers or pressure measuring lines, which separate or after merging are led out of the probe with other pressure measuring lines from other measuring chambers. The probe has a disk-shaped base construction, with two rectangular disks or circular sector disks, which are arranged in the dome of a flow body, being able to detect a wide solid angle.

Claims

1. A probe for measuring fluid flows, characterized in that it has two or more measuring chambers (1,2,3,4,5,6) with rectangular or slit-shaped openings which are arranged essentially along an arc or along the periphery of a circle , in which backpressures can develop under the influence of the flow, and that measuring devices for determining the pressure in the measuring chamber and / or for determining differential pressures between two measuring chambers or pressure measuring lines (11, 12 , 13, 14), which are led out of the probe separately or after merging with other pressure measuring lines from other measuring chambers.

2. Probe according to claim 1, characterized in that the measuring chambers (1, 2, 3, 4, 5, 6) are formed at least in their outer area near the circular arc or the circular periphery and there their inner cavity has a uniform thickness.

3. Probe according to claim 1 or 2, d a d u r c h g e k e n e z e i c h n e t that two measuring chambers (1, 2, ...) with their side walls abut each other at the ends of their rectangular or slit-shaped openings.

4. A probe according to claim 2 or 3, characterized in that the measuring chambers (1, 2, ...) are circular sector-shaped discs with an acute angle of preferably 45 °, which form a circular disc or one or more sector sections (e) of a circular disc .

5. A probe according to claim 4, characterized in that two adjacent measuring chambers (3, 4) are pressure-connected to each other in their rear area and the two measuring chambers (5, 6) diametrically opposite these measuring chambers are also pressure-connected to each other and the two connecting lines (16 , 17) are brought together to make the resulting pressure (p _stat ) measurable.

6. Probe according to claim 5, characterized in that between the two pairs of measuring chambers (3, 4; 5, 6) a further pair of measuring chambers (1,2) is provided, each of which measuring chamber has a separate pressure measuring output in the form of pressure measuring lines ( 11, 12) for measuring the pressure difference between these measuring chambers outside the chambers, or that a measuring device is provided for directly measuring the pressure difference between the two additional measuring chambers (1, 2).

7. Probe according to claim 5, d a d u r c h g e k e n n z e i c h n e t that between the two pairs of measuring chambers (3, 4; 5, 6) another pair of measuring chambers

(1,2) is provided in its rear area are connected to each other in terms of pressure, and that the connecting line (15) is led out of the measuring chambers in order to measure the resulting pressure as a total pressure, the additional pair of measuring chambers (1, 2) being used together as a pitot tube.

8. A probe according to claim 6 and 7, characterized in that the measuring chambers of the additional pair of measuring chambers (1, 2) both have pressure measuring lines (11, 12) led out separately from the chambers and are also connected to one another in terms of pressure and the common connecting line (15) from the Measuring chambers is led out.

9. A probe according to claim 1 or 2, characterized in that it is a circular disc and contains at least in its outer regions circular sector-shaped measuring chambers (1,3,5,7), which are not all abutting, but are arranged with gaps so that their measuring openings are arranged on or along the periphery of the circle.

10. A probe according to claim 1 or 2, d a d u r c h g e k e n e z e i c h n e t that it is a circular disc and contains at least in its outer areas circular sector-shaped measuring chambers, at least some of which are connected in terms of pressure to another or more others in their rear areas facing away from the peripheral area.

11. Probe according to one of claims 1 to 4, characterized in that it contains four measuring chambers (1,2,3,5), which are circular sector-shaped and are arranged so as to abut one another so that they form a circular sector-shaped disk, and four further essentially contains similar measuring chambers in the same arrangement, which are perpendicular to the first four Measuring chambers are arranged, the line of intersection running through the axes of symmetry of the two circular sector-shaped disks and pressure measuring lines being led out of the eight measuring chambers towards the rear in the direction of the pointed parts of the measuring chambers.

12. A probe according to any one of claims 1 to 4, characterized in that it contains six measuring chambers (1,2,3,4,5,6) which are designed in the shape of a sector of a circle and are arranged so as to abut one another so that they form a sector-shaped disk, and contains six further essentially identical measuring chambers in the same arrangement, which are arranged at right angles to the first six measuring chambers, the intersection line running through the axes of symmetry of the two circular sector-shaped disks and pressure measuring lines (11, 12, ..) from the twelve measuring chambers directly and / or as connecting lines (15, 16, 17, ...) selected measuring chambers are led out of one another towards the rear in the direction of the pointed parts of the measuring chambers.

13. A probe according to any one of claims 11 or 12, that the pressure measuring lines led out of the measuring chambers are accommodated in a tube designed as a holder for the probe.

14. A probe according to claim 13, d a d u r c h g e k e n n z e i c h n e t that it is encapsulated in a housing with low flow resistance, which has a spherical cap shape on the front.

15. A probe according to claim 1 or 10, characterized in that it contains at least two outwardly open measuring chambers (31, 33) with the same effective dynamic pressure measuring opening (20), which are axially symmetrical so that their measuring openings point in opposite directions, and measuring device lines (44) for determining the pressures in the measuring chambers and / or for determining the differential pressure between the measuring chambers are provided in the rear parts of the measuring chambers.

16. A probe according to claim 15, characterized in that four measuring chambers (31,32,33,34) are provided, two of which are arranged axially symmetrically opposite one another and the other two, also axially symmetrically opposite one another, essentially at right angles the first pair of measuring chambers are arranged, with all four dynamic pressure measuring openings (20) being equidistant from the common axis of symmetry.

17. A probe according to claim 15 or 16, characterized in that each measuring chamber (31,32,33, 34) is divided into several partial chambers (1,2,3,4, ..), each of which has an outward-facing dynamic pressure measuring opening ( 20, 20 ', 20 "), and in each sub-chamber a measuring device (44) is provided for determining the pressure and / or the differential pressure with respect to the sub-chamber opposite it axially-symmetrically.

18. A probe according to claim 17, which also includes a plurality of sector-shaped partial chambers (1, 2, 3, 4, 5,...) With their

Side faces are arranged so that the end points (33) of the side faces lie on a circle, and two or more partial chambers (1, 2, 3) each form a measuring chamber (31), pressure measuring lines (44) from these partial chambers forming a common one Pressure measuring line (45; 47) of the measuring chamber (31; 33) are brought together.

19. A probe according to claim 18, characterized in that individual subchambers (1; 3; 5; 7) simultaneously have parts of two different measuring chambers (31, 34; 31, 32; ..), whereby the measuring chambers partially overlap.

20. A probe according to claim 19, which also includes eight subchambers which are connected to four measuring chambers, each with three subchambers.

21. A probe according to any one of claims 15 to 20, so that it has the shape of a circular cylindrical disk, along the outer edge of which the measuring openings (20, 20 ', 20 ") of the partial chambers or measuring chambers are uniformly distributed.

22. A probe according to claim 21, d a d u r c h g e k e n n z e i c h n e t that a further circular cylindrical disk with measuring openings evenly distributed along its edge is provided by partial chambers perpendicular to the former and running through the center thereof to detect a solid angle.

23. A probe according to claim 21 or 22, characterized in that three identical circular cylindrical disks with partial chambers are combined at right angles to one another and with a common center to form an all-round space probe, the partial chambers being used at least twice for the measurements at the intersection points of the disks, ie each belong to at least two measuring chambers.

24. Probe according to one of claims 15 to 23, characterized in that the measuring devices comprise open tubes, the measuring openings of which are located in the rear part of a measuring chamber or a partial chamber and the other end of which is connected to a mechanical differential pressure gauge the other side of which the opposite measuring chamber or partial chamber is connected.

25. Probe according to any one of claims 15 to 23, that the measuring devices comprise open pressure lines, the measuring openings of which are arranged in the rear part of a measuring chamber or a partial chamber and the other ends of which are connected to piezo-crystal pressure probes.

26. Probe according to one of claims 15 to 23, characterized in that the measuring devices comprise open tubes, the measuring openings of which are located in the rear part of a measuring chamber or a partial chamber and the other end with a pressure line (45) to the measuring tube in the opposite associated chamber is connected, temperature-dependent electronic components (46), such as temperature-dependent resistors, semiconductor sensors or barrier elements, are arranged in this pressure line (45, 47), the temperature change of which is electronically recorded and converted into pressure difference values.

27. A probe according to claim 26, characterized in that a combination of two resistors (46) with a negative temperature coefficient (subminiature NTC) is arranged in the pressure line (45, 47), which form part of a bridge circuit in which the NTC Resistors are used as parts of the voltage divider circuit, the pressure difference between two measuring chambers (33 and 31) being determined from the changes in resistance.

28. A probe according to any one of claims 15 to 23, characterized in that the measuring devices for determining the pressures in the measuring chambers and / or the differential pressure between the measuring chamber are arranged outside the probe and are connected to the measuring chambers via rigid or flexible pressure lines, the measuring openings of the pressure lines being located in the rear part of each measuring chamber.

29. Probe according to one of claims 16 to 28, characterized in that the pressure difference between two opposite, assigned measuring chambers is converted into a first electrical analog signal and the pressure difference between two opposite, associated measuring chambers, which are arranged at right angles to the first pair of measuring chambers, is converted into a second electrical analog signal, and two operational amplifiers are provided, to which these signals are each fed, the outputs of which are connected on the one hand to the inputs of an analog computer, which analyzes them for size and sign and feeds the result signal to a direction indicator (compass), and on the other hand, are connected to the inputs of squaring circuits which squared the analog signals, after which the result signals are fed to a summing circuit which sends the sum signal of the squared signals to a flow rate display device leads.

30. A probe as claimed in claim 29, so that the analog computer generates an arc tan function from the input signals.

31. Probe according to one of claims 15 to 23, characterized in that the partial chambers or measuring chambers are closed in their front part with a thin elastic membrane which transmits the pressure without contamination into the interior of the chamber.

32.Sonde according to claim 31, d a d u r c h g e k e n n z e i c h n e t that the interior of the sub-chambers or measuring chambers with an incompressible pressure measuring medium such as e.g. Oil is filled and the pressure measuring device is arranged completely inside the chamber and the measured pressure value is output electrically from the chamber.

33. A method for measuring fluid flows with respect to direction and strength, characterized in that the pressures are measured in at least two directions of a plane, which occur in measuring chambers with dynamic pressure measuring openings, which are at fixed angles to each other, under the influence of the flow, and from differences the direction of the flow or dynamic pressure components are determined from pressure measured values and / or the total pressure (dynamic pressure plus static pressure) is determined from sums of pressure measured values and / or from pressure measured values which are measured in measuring chambers which are so remote from the flow direction that the Flow builds up no back pressure in them, the static pressure is determined and / or the flow rate is determined by mathematical processing of pressure measurements or differences thereof.

34. The method of claim 33, d a d u r c h g e k e nnz e i c h n e t that measuring chambers are used with rectangular or slit-shaped back pressure openings, which are arranged substantially along an arc or along the periphery of a circle.

35. The method according to claim 35, dadurchgeke nnz eichnet that disk-shaped measuring chambers with circular sector-shaped plan, preferably with an acute angle of 45, which are arranged abutting, are used.

36.Procedure according to one of claims 33 to 35, d a d u r c h g e k e n n z e i c h n e t that in addition, the pressures in at least two directions of a second level, which to the first level under a

An angle, preferably a right angle, is measured using measuring chambers with essentially the same structure and the same arrangement as in the first plane and determines the three-dimensional spatial direction of the flow or dynamic pressure components from differences in pressure measurement values of measuring chambers from both planes are and / or from sums of pressure measurements from measuring chambers of one or both levels the total pressure (dynamic pressure plus static pressure) is determined and / or from pressure measurements that are measured in measuring chambers of one or both levels, which are so facing away from the flow direction that the Flow builds up no back pressure in them, the static pressure is determined and / or the flow rate is determined by mathematical processing of pressure measurements or differences thereof.

37. The method as claimed in claim 36, so that the total pressure and the static pressure are used to determine the dynamic pressure and from this the velocity of the flow relative to the measuring location (the measuring chamber arrangement).

38. The method according to claim 33, characterized in that the dynamic pressure of the flow is measured in at least one chamber system, which is opposed axially symmetrically to a second chamber system with the same effective dynamic pressure opening, in which the pressure which is also established is measured as a reference pressure, and from this determined or directly measured pressure difference between the two Chamber systems is obtained as a first reference variable, and the dynamic pressure is measured in a third chamber system, rotated preferably 90 against both the first and the second chamber system, with the same effective dynamic pressure opening, to which a fourth chamber system with the same effective dynamic pressure opening lies axially symmetrically and the difference to the reference pressure measured in the fourth chamber system is determined or measured directly, which supplies a second reference variable, and determines the direction of the flow from the comparison of the two reference variables and / or the strength of the flow from the sum of the squares of the two reference variables is determined.

39. The method according to claim 38, characterized in that all four chamber systems are each formed in the shape of a sector of a circle and are arranged such that their dynamic pressure openings lie in a plane on a circle, and the first reference variable signal as a function of the incident angle is essentially a sinusoidal curve and the second reference variable signal as a function of Inflow angle essentially has a cosine curve.

40. The method of claim 39, so that the two reference quantity signals are processed electronically in an analog computer which calculates the arc tan value from the quotient of the sine signal and the cosine signal, which is a measure of the angle of attack.

41. The method according to claim 39, characterized in that the two reference quantity signals are electronically squared and summed to get a measure of the strength of the flow.

42. The method according to claim 38 or 39, characterized in that each of the four chamber systems each consist of a plurality of individual subchambers, all of which are sector-shaped and arranged abutting one another, with their dynamic pressure measuring openings lying in a plane on a circle, with a plurality of adjoining subchambers Form a chamber system and individual subchambers belong to two chamber systems at the same time.

43. The method according to claim 42, characterized in that there are a total of eight subchambers, each of the four chamber systems consists of three subchambers which are connected to a pressure measuring tube, and the pressure differences of the respectively opposing two chamber systems are measured and processed as the two reference values .

44. Use of the probe according to one of claims 1 to 32 for aircraft, helicopters or other missiles, in particular using a method according to one of claims 33 to 43.