DE102010053231A1 - Magnetic sensor arrangement useful for height detection on burner, preferably autogenous burner, comprises at least one magnetic coil and a magnetic flow guide means, which is arranged between lower burner end and magnet coil - Google Patents

Abstract

Magnetic sensor arrangement for height detection on a burner, preferably an autogenous burner comprising a cutting- or a welding tool, preferably a cutting nozzle (1) and a heating nozzle (2) attachable to a burner head (3), comprises at least one magnetic coil and a magnetic flow guide means, which is arranged between a lower burner end and at least one magnet coil. The burner exhibits no ferromagnetic properties. The sensor arrangement is attachable as a separate subassembly directly on the burner. Magnetic sensor arrangement for height detection on a burner, preferably an autogenous burner comprising a cutting- or a welding tool, preferably a cutting nozzle (1) and a heating nozzle (2) attachable to a burner head (3), comprises at least one magnetic coil and a magnetic flow guide means, which is arranged between a lower burner end and at least one magnet coil. The burner exhibits no ferromagnetic properties. The sensor arrangement is attachable as a separate subassembly directly on the burner. At least one magnetic coil (7) with a coil core (8) or at least one coil carrier is attachable above the cutting- or welding tool to a burner shaft. The magnetic flux guiding means is formed as a hollow polar cap of ferromagnetic material, which is connected to the coil core or at least one coil carrier of the magnet coil and which is further designed so that a burner section is laterally enclosed at least between the magnetic coil and the lower burner end and is tapered downward.

Description

The invention relates to a magnetic sensor arrangement for detecting the height of a burner, in particular an autogenous burner, according to the preamble of claim 1.

In general, according to the prior art, a sensor system is connected to a burner, in particular an autogenous burner, as a tool in order to position it as accurately as possible at a defined distance above the workpiece for the thermal processing of metals for the machining process. For this purpose, the actual distance between the workpiece and the tool is determined with the sensor arrangement, which is connected to the tool, to form from the corresponding distance information a reference variable for a distance control.

There are a variety of magnetic sensor assemblies for height detection on a burner of the prior art, which differ from capacitive sensor assemblies by a lower sensitivity to foreign influences such as slag spray that occur when working with a cutting torch and can lead to a pulse-like falsification of the distance information. Also magnetic sensor assemblies are insensitive to water vapor and water splashes that can occur during a cutting process.

In a known magnetic sensor arrangement of the type mentioned, the sensor arrangement is a magnet system which is arranged concentrically with at least four coils around the outer end of a gas nozzle of a welding torch, wherein in each case a coil pair of two opposing coils is excited by a high-frequency alternating current and in a second Coil pair with two opposing coils, a current is induced which includes distance information ( DE 37 23 844 A1 ). Specifically, such a sensor consists of a soft magnetic ring with four magnetic yokes as magnetic flux guide means between the lower end formed as a pole shoes through the coils wound on the yokes, a magnetic field is generated over the workpiece whose field component is substantially in the plane of the workpiece. As a measure of the distance of the gas nozzle or the tool on the workpiece, the degree of magnetic coupling between the magnetic yokes or coils is evaluated. The problem is the design of the pole pieces at the lower ends of the magnetic yokes, which must be brought as close to the workpiece and thus are exposed to the influences of the cutting process. Worn pole pieces are to be replaced as wear parts and aligned after assembly.

The latter disadvantages also apply to inductive sensor arrangements, each with a sensor ring arranged closely above the workpiece for inductive distance measurement between the workpiece and the tool ( DE 199 19 485 A1 . DE 27 26 648 A . GB 840 275 ). The sensor ring, which can be designed as a loop of a copper conductor and surrounds the tool, is relatively bulky. With the sensor ring or the loop or winding of a coil, a distance signal is formed, which depends on the magnetic coupling between the sensor ring or the coil and the workpiece. For this purpose, two sensor rings can be arranged one above the other.

In another non-generic magnetic sensor arrangement on a burner, the burner head and at least one of the cutting or welding tools contains ferromagnetic material and forms at least part of the sensor body ( DE 103 32 422 B4 ). In particular, coils of the sensor arrangement are arranged on the burner head. The ferromagnetic material in the burner head and at least one of the cutting or welding tools conducts the magnetic flux between a lower burner end and the coils. The sensor body is thus formed by the burner head itself and the sensor tip, ie in particular a cutting and heating nozzle and a retaining ring which surrounds the nozzle cap-shaped, to bring the magnetic field generated with him to the workpiece surface. It is therefore not a separate, outside the burner head to be arranged sensor body, as proposed in the other prior art, may be required. However, it is disadvantageous that the ferromagnetic material required for performing the sensor function of at least one of the cutting or welding tools is not optimal for cutting and for the life of the cutting tools, which is why burners and cutting tools generally consist of copper or brass. On the other hand, conventional burners and cutting tools made of brass or copper can not be readily retrofitted with a sensor arrangement according to the principle of this known sensor arrangement, but the burner head and at least one of the cutting and welding tools would be replaced by those of ferromagnetic material.

The present invention has for its object, while avoiding the disadvantages of the prior art magnetic sensor assemblies, a sensor assembly to a conventional burner of non-ferromagnetic material, ie retrofit from brass or copper uncomplicated to a compact unit. The sensor arrangement should therefore can also be retrofitted to already in operation burners. This should also be an improved replacement of existing sensor arrangements for height detection possible.

This object is achieved with a magnetic sensor arrangement for height detection on a burner with the features of claim 1.

Due to the fact that the sensor arrangement can be attached directly to the burner as a self-contained assembly, a replacement of burner components by those of the sensor arrangement is eliminated. The unit of the burner with the sensor assembly may be compact because of the direct attachment of the sensor assembly to the burner. For attachment to any burner - without ferromagnetic material - the brewing assembly of the sensor assembly can be flexibly designed for suitable mechanical mounting variants.

More particularly, the inventive sensor arrangement on the burner is characterized in that the at least one magnetic coil of the sensor arrangement with a coil core or at least one coil carrier above the cutting or welding tool on a burner shaft is attachable after the solenoid, in particular with the coil core on the Burner shaft is pushed, and that the magnetic flux guide means are formed as a hollow pole cap, which is connectable to the coil core or the at least one coil carrier of the magnetic coil, and which is further adapted to form a burner section at least between the magnet coil and the lower burner end side includes and tapers down. The lateral confinement of this burner section may preferably be practically complete except for a small portion between the lower end of the pole cap and the lower end of the heating nozzle.

The sensor assembly is in particular simply mounted to the burner by the at least one solenoid is pushed with the coil core from below onto the burner shaft and is attached thereto, after which the hollow pole cap is attached from below to the magnetic coil and is connected to the magnetic coil.

Advantageously, the retrofittable sensor arrangement is functionally independent of the burner. The assembly according to the invention of the magnetic coil, the coil core or the at least one coil carrier and the polar cap is easy to manufacture and assemble. The burner, with which the assembly of the sensor arrangement is integrated, is not to be modified except, if appropriate, with a mounting element for the sensor arrangement.

Therefore, the burner can maintain its favorable cutting properties and a life remains unimpaired.

The tapered hollow pole cap forms a good magnetic conductor between the magnetic coil and the lower burner end from which the magnetic field extends to the surface of the workpiece. The taper realizes a close bundling of the magnetic field to a precise distance measurement. The influence of the magnetic field by the distance between the lower burner end and the lower end of the pole cap and the workpiece surface is detected by evaluating an electrical signal from the at least one magnetic coil according to one of the known measuring methods.

As a measuring method, the known methods such as pulse induction measurement, transforming method and active power method can be used. With the active power method after the DE 38 14 131 C2 a field loss resistance is measured as a function of the lower burner end or here the lower end of the pole cap of the workpiece surface.

The coil according to claim 2 preferably comprises the coil core of ferromagnetic material, to which the pole cap is attached in order to guide the magnetic flux generated in the coil largely lossless or the lower, tapered Polkappenende or the lower burner end.

In an assembly variant according to claim 3, the magnetic coil is attached to the at least one coil carrier made of non-ferromagnetic material on the burner shaft and the pole cap is in the at least one coil carrier, d. H. inserted under these and connected to the bobbin. The magnetic coil is then outside with respect to the bobbin. The pole cap is slightly longer for this mounting variant than for the mounting method according to claim 2 and the magnetic coupling between the magnet coil and pole cap is slightly less, but less dependent on mechanical assembly tolerances.

The pole cap made of ferromagnetic material preferably tapers so strongly according to claim 4 that it bears against the lower burner end in a form-fitting manner laterally. With this form-fitting prevents slag splash in the operation of the burner penetrate into a space between the polar cap and burner and contaminate the burner.

For a compact design of the magnetic sensor arrangement with good magnetic flux line, the pole cap according to claim 5 in Formed substantially geometrically similar to the portion of the burner, which it includes laterally, optionally with a small gap. The gap allows differential thermal expansion of the pole cap and the burner and reduced heat transfer between these parts.

In a simple shaping of the pole cap according to claim 6, this is similar to the burner section, which it includes, formed with an upper cylindrical portion and a lower conical portion. The indications "upper", "lower" refer to the normal operating position of the burner.

In the embodiment according to claim 2, wherein the pole cap is attached to the spool core, the connection between the spool core and the pole cap according to claim 7 advantageously with a bayonet closure, parts of which are respectively arranged on the bobbin and the pole cap. The bayonet lock allows a quick removal of the polar cap and thus a quick access to the nozzles of the burner.

In the variant according to claim 3, is inserted in the pole cap in at least one bobbin, the pole cap can also be advantageously mounted with a bayonet lock on the bobbin according to claim 8 or according to claim 9 by means of a coarse thread.

In order to increase the service life of the pole cap by reducing the adhesion of slag splashes or completely avoided, the surface of the pole cap according to claim 10 is coated corrosion-resistant. In particular, the pole cap according to claim 11 may be chromed thereto.

The invention will be described below with reference to embodiments with six figures, resulting in further details, features and advantages of the invention. Show it:

1 a section of a prior art conventional cutting torch without sensor assembly in a plane in which the vertical center axis is located, cut,

2 the cutting torch according to 1 , but with a part of a first embodiment of the sensor arrangement in a section corresponding 1 .

3 the cutting torch according to the 1 and 2 in the same representation, but with fully assembled first embodiment of the sensor arrangement,

4 the essential components of the first embodiment of the sensor arrangement in the same plane in which the cutting torch and the first embodiment of the sensor arrangement in the 1 - 3 shown in split condition prior to mounting on the cutting torch,

5 the first embodiment of the sensor arrangement in the same schematic representation as in 4 but assembled as mounted on the cutting torch, and

6 a mounted on the cutting torch second embodiment of the sensor assembly in a same sectional plane as in the 1 - 5 ,

According to the figures, matching parts are provided with the same reference numerals.

According to the 1 - 3 and 4 is a cutting nozzle 1 in a cap-like heating nozzle 2 used on a burner head 3 by means of dowel pins 4 . 5 is held. The dowel pins 4 . 5 To do this, use unmarked bayonet grooves in the heating nozzle 2 one. As can be seen protrudes an upper end of the burner head 3 in a tubular burner shaft 6 into it.

In the 1 shown parts of the cutting torch are made of brass or copper.

On the cutting torch according to 1 a sensor arrangement can be retrofitted, whose parts in the 4 and 5 are shown in a dissolved state of the cutting torch.

Thus, the sensor arrangement comprises a cylindrical magnetic coil 7 with a bobbin or coil core 8th inside a cylindrical cavity 9 between flanges 10 . 11 having. The spool core is made of ferromagnetic material.

The sensor assembly is completed by a ferromagnetic Pohlkappe 12 , which are in the assembled state of the sensor arrangement, see also 5 , below the magnetic coil 7 is and is releasably connected to this with a bayonet lock, not shown in the drawing.

The polar cap 12 is geometrically shaped similar to a cap-like heating nozzle 2 but with such a large interior 13 that they are the heating nozzle 2 can include. Thus, the pole cap has an upper, inner and outer cylindrical portion 14 and a lower inside and outside conical section 15 on. She can handle these sections 14 . 15 , as shown, be made in one piece. The conical section 15 has a lower opening 16 through which a lower end of the heating nozzle 2 with the cutting nozzle 1 can pass through, however the heating nozzle 2 with a positive fit inside the opening 6 the polar cap 12 limiting section, which is not indicated in the drawing, but in particular 3 is apparent, is present. For this purpose, the conical section runs 15 the polar cap 12 pointed down to. Furthermore, between the heating nozzle 2 and the polar cap 12 a gap 17 remain free, so that the polar cap does not need to be formed inside exactly the same as the outer wall of the heating nozzle everywhere. In addition, the gap acts 17 favorably thermally insulating.

An assembly of the first embodiment of the sensor arrangement according to 4 on the cutting torch according to 1 - 3 done so that first the magnetic coil 7 with her spool core 8th on the burner shaft 6 is pushed, with the burner head 3 with the heating nozzle 2 and the cutting nozzle 1 from the burner shaft 6 is solved. The coil core 8th becomes permanent at the burner shaft 6 fixed. Then the ferromagnetic pole cap 12 detachable on the spool core 8th be attached, for. B. with a bayonet lock, the parts of the polar cap 12 or the spool core 8th are arranged, which are not shown in the drawing. When attaching the polar cap 12 can the burner head 3 with the heating nozzle 2 and the cutting nozzle 1 again with the burner shaft 6 communicate because of the interior 13 the polar cap 12 so big is that he has the cap-shaped heating nozzle 2 and may include the lower part of the burner head without affecting it.

The second embodiment of the sensor arrangement according to 6 first differs from the first embodiment in that the magnetic coil 19 together with a ferromagnetic coil core not directly on the burner shaft 6 externally adjacent to this is pushed, but by means of a non-ferromagnetic material consisting of coil carrier 20 on which the magnetic coil 19 is attached, indirectly on the shaft 6 is attached. Besides, here is the polar cap 21 made of ferromagnetic material so long or in the drawing high that they under the on the shaft 6 fixed ironless bobbin can grab to the in the solenoid coil 19 can be generated low-loss magnetic flux to the lower end of the pole cap 21 forward. The pole cap extends in this case in a lower part of the bobbin 20 up to about the height of an upper end face of the solenoid 19 , Inside is the polar cap 21 essentially like the polar cap 12 formed the first embodiment, wherein only the cylindrical portion 22 extends higher.

After the pole cap from below into the magnetic coil 19 or the coil carrier 20 is pushed, it can be releasably attached to the bobbin on a bayonet lock, not shown, or also not shown thread. Thus, as in the first embodiment, after loosening and removing the pole cap 21 an exchange of the cutting nozzle 1 and / or the heating nozzle 2 unhindered possible, after which the sensor assembly is functional again by re-attaching and securing the pole cap.

The magnetic coil 9 or 19 may comprise a plurality of individual coils, with each of which one of the different methods of inductive distance detection or measurement can be performed, such as pulse induction measurement, measurement according to the transformer principle or active power measurement.

LIST OF REFERENCE NUMBERS

1

cutting nozzle

2

heating nozzle

3

burner head

4

dowel

5

dowel

6

torch sleeve

7

solenoid

8th

Plunger

9

cavity

10

flange

11

flange

12

polar cap

13

inner space

14

cylindrical section

15

conical section

16

opening

17

gap

18

lower burner end

19

solenoid

20

coil carrier

21

polar cap

22

cylindrical section

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3723844 A1 [0004]
• DE 19919485 A1 [0005]
• DE 2726648 A [0005]
• GB 840275 [0005]
• DE 10332422 B4 [0006]
• DE 3814131 C2 [0015]

Claims (11)

Magnetic sensor arrangement for height detection on a burner, in particular an autogenous burner ( 1 - 6 ), one on a burner head ( 3 ) attachable cutting or welding tool, in particular a cutting nozzle ( 1 ) and a heating nozzle ( 2 ), wherein the burner has no ferromagnetic properties and wherein the sensor arrangement comprises at least one magnetic coil and magnetic flux guide means which are arranged between a lower burner end and the at least one magnetic coil, characterized in that the sensor arrangement ( 7 . 8th . 12 respectively. 19 . 20 . 21 ) can be attached directly to the burner as a separate assembly, that for this purpose the at least one magnetic coil ( 7 respectively. 19 ) with a spool core ( 8th ) or at least one coil carrier ( 20 ) above the cutting or welding tool ( 1 . 2 ) on a burner shaft ( 6 ) and that the magnetic flux guide means as a hollow pole cap ( 12 . 21 ) are formed of ferromagnetic material with the coil core ( 8th ) or the at least one coil carrier ( 20 ) of the magnetic coil ( 7 respectively. 19 ) is connectable and which is further adapted to a burner section at least between the magnetic coil ( 7 respectively. 19 ) and the lower burner end ( 18 ) laterally and tapers downwards. Sensor arrangement according to claim 1, characterized in that the coil core ( 8th ) of the magnetic coil ( 7 ) consists of ferromagnetic material and that the polar cap ( 12 ) on the spool core ( 8th ) is attached. Sensor arrangement according to claim 1, characterized in that the magnetic coil ( 19 ) with the at least one coil carrier ( 20 ) of non-ferromagnetic material on the burner shaft ( 6 ) is attachable and that the polar cap ( 12 ) in the at least one coil carrier ( 20 ) is insertable and connectable with this. Sensor arrangement according to one of the preceding claims, characterized in that the pole cap ( 12 . 21 ) at the lower burner end ( 18 ) is present laterally positive. Sensor arrangement according to one of the preceding claims, characterized in that the pole cap ( 12 . 21 ) substantially geometrically similar to the section of the burner ( 1 - 6 ), which it encloses laterally. Sensor arrangement according to claim 5, characterized in that the pole cap ( 12 . 21 ) an upper cylindrical section ( 14 ) and a lower conical section ( 15 ). Sensor arrangement according to one of claims 2, 4-6, characterized in that the coil core ( 8th ) and the polar cap ( 12 ) Have parts of a bayonet closure, so that the pole cap ( 12 ) by means of the bayonet closure on the spool core ( 8th ) is releasably attachable. Sensor arrangement according to one of claims 3-6, characterized in that the at least one coil carrier ( 20 ) and the polar cap ( 21 ) Have parts of a bayonet closure, so that the pole cap ( 21 ) by means of the bayonet closure on the at least one coil carrier ( 20 ) is releasably attachable. Sensor arrangement according to one of claims 3-6, characterized in that the pole cap ( 21 ) by means of a helical thread in the at least one coil carrier ( 20 ) is attachable. Sensor arrangement according to one of the preceding claims, characterized in that the pole cap ( 12 . 21 ) is coated corrosion resistant. Sensor arrangement according to claim 10, characterized in that the pole cap ( 12 . 21 ) is chrome plated.

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