DE102009059108A1 - Electrode with cooling tube for a plasma cutting device - Google Patents

Abstract

Plasma electrode for a cutting device, which consists of an electrode body with an axial, central receptacle for an electrode core which is disposed on the end face, a coolant flow in the axial direction flowing through at least one radially outer annular gap in the interior of the electrode body, and a radially inner liquid channel through an exchangeable one Cooling tube is formed, which is positioned by one or more stops on the electrode body and whose front end, which is closest to the electrode core, engages in the annular recess of the electrode body, in which the coolant flow is deflected, at least one stop being formed on the inside of the electrode body.

Description

Field of the invention

The invention relates to a spacer for the cooling tube of an electrode of a plasma cutting device.

State of the art

Plasma cutters are used to separate all electrically conductive materials. The plasma cutter consists for example of an inverter, a handpiece, a ground cable, a power supply line and a compressed air supply line.

• • Hervorragende Eignung im dünnen und mittleren Baustahlbereich (bis 30 mm)
• • Schneiden hochfester Baustähle mit geringer Wärmeeinbringung
• • Hohe Schneidgeschwindigkeiten
• • Sehr gute Automatisierbarkeit.

The following points have proven to be significant advantages in plasma cutting:

• • Excellent suitability in thin and medium structural steel area (up to 30 mm)
• • Cutting high strength structural steels with low heat input
• • High cutting speeds
• • Very good automation.

A plasma is an electrically conductive gas in which an arc is ignited almost exclusively with high-frequency ignition and is pinched at the outlet by an insulated, usually water-cooled, copper nozzle. The high energy density melts the metal. The molten metal is blown away by a gas jet, creating the kerf.

The electrode of a plasma cutting apparatus has an elongate hollow body with an open end and a closed end. It is preferably formed of copper, but other materials such as copper and silver alloys are possible. In the lower part of the electrode, a cylindrical insert made of a material with high thermionic emissivity is pressed into a bore in the center. This material represents the electrode core and is preferably made of z. Hafnium, zirconium or tungsten.

It is thus already known from the state of the art that the cooling liquid is conducted to the lower end of the electrode via a cooling tube lying in the electrode. Due to the circulating liquid, sufficient cooling of the electrode takes place.

The internal cooling tube requires a relatively fixed position relative to the electrode in order to make good use of the characteristic of the circulating cooling flow. This is an important point in terms of increasing the life of the electrode.

From the prior art, a certain positioning of the cooling tube relative to the electrode body is already known.

The EP 2 082 622 shows an internal, cylindrically shaped cooling tube that has a predetermined position relative to the electrode body. This is achieved by a radially projecting shoulder on the peripheral surface of the cooling tube in conjunction with a mating stop on the electrode housing side. The cooling tube is thus held in the upper region and so selectively positioned relative to the electrode body.

However, this embodiment is very expensive and expensive to produce. Due to the heel on the peripheral surface of the cooling tube and the required stop on the electrode body side accurate positioning is difficult.

Subject of the invention

The invention is therefore based on the task of a simple and universal stop for the cooling tube ready.

To solve the problem, the invention is characterized by the technical teaching of claim 1.

The solution of the problem is achieved by the technical teaching of claim. 1

An essential feature of the invention is that at least one axial stop for the cooling tube is formed on the inside of the electrode body.

Although the invention also provides for the arrangement of a plurality of stops, the simpler description will be described only for the arrangement of a single stop closer. However, this is not intended to limit the scope of disclosure of the invention. Thus, if the following description refers to a single attack, it is to be understood as "one or more attacks".

In a first preferred embodiment, the electrode body has a central bore in the lower region, which accommodates an electrode core. The electrode core extends in the direction of the interior of the electrode body and is held by a cylindrically shaped receptacle in the electrode body. To ensure better cooling of the electrode, the receptacle of the electrode core is surrounded by an annular recess in the interior of the electrode body, in which the cooling liquid can circulate. This allows a Good heat dissipation and thus extends the life of the electrode.

New in the invention is now that the cooling tube is spaced by a stop in the annular recess on the side of the electrode. This allows a good circulation of the cooling liquid in the lower region of the electrode body.

Thus, the invention provides to displace the axial movement of the cooling tube limiting stop in the inside of the electrode body and that in the vicinity of the end face of the electrode body. The stop is thus laid in the circumferential annular recess in the vicinity of the end face of the electrode body inside.

The stop is thus located on the electrode side and may preferably be formed as a rectangular or round, extending in the axial direction tooth. It is crucial that the size of the stop largely does not affect the flow of the cooling liquid. The front end side of the cooling tube is now on the front side of the dipping into the cooling liquid, pointing in the axial direction tooth.

In order to achieve a good quality of the electrode together with the stop, in a preferred embodiment the electrode can be produced by a pressing process. By means of the pressing process, the special design of the electrode can be produced without cutting, together with the axially aligned stop, thus reducing the need for costly, post-machining machining. It is also possible to attach the stop for the cooling tube in a second process to the electrode body.

Instead of a pressing process, the tooth-shaped stop can also be achieved by a machining of the annular recess on the inside of the electrode body. In this case, an axially aligned end mill moves into the central inner bore of the electrode body and mills the bottom of the annular recess in the circumferential direction progressively by a circumferential angle of z. B. 355 degrees, so that remains in the remaining angular range of 5 degrees of the tooth-shaped stop as material increase.

In a further embodiment, a plurality of stops or stop teeth are present in the annular recess on the electrode body, which position the cooling tube on the front side stop limiting with respect to the electrode.

Instead of the formation of one or more axially directed attacks can also be provided that the stop is not located on the bottom of the annular recess in the electrode body, but instead on the side walls of the annular recess, which then in a radial direction in the interior of the annular recess protruding tooth results.

All the above-described embodiments relate to the fact that the stop is made of one piece material from the material of the electrode body out. The invention is not limited thereto. It may be provided in a development that the (axial or radial) stop is anchored as a stop screw or stop pin anchored in the material of the electrode body. Such an anchoring can be made detachable or non-detachable. It can be designed as gluing, welding, drilling or screwing. In this case, such a stop also consist of a different material than the material of the electrode body.

Finally, it is provided in a further embodiment that the stop is arranged on a ring which is inserted or pressed into the annular, circumferential recess in the electrode body or fixed in some other way. Of course, the ring can also be fixed in this recess by means of clamping means in order to avoid strike-off or flushing with the cooling liquid.

In the following the invention will be explained in more detail with reference to drawings showing only one embodiment. Here are from the drawings and their description further features essential to the invention and advantages of the invention.

Show it:

1 : Schematic representation of a plasma electrode with an end stop on the electrode body

2 : Schematic representation of a plasma electrode with a radial stop on the inner wall of the electrode body

3 : Schematic representation of a plasma electrode with a radial stop on the outer wall of the electrode body

4 : Schematic representation of a plasma electrode with a radial, end stop on the inner wall of the electrode body

5 : Schematic representation of a plasma electrode with a radial, end stop on the outer wall of the electrode body

6 : View of the central inner bore of the electrode body in the direction of arrow VI in 1 with a stop for a cooling tube

7 : Perspective view of a ring with a stop for a cooling tube

8th : Representation of a modified version of a ring with two radial, internal stops

1 shows a plasma electrode 1 consisting essentially of an electrode body 2 and a cooling tube 3 consists. The plasma electrode 1 can be interchangeably fixed by press fitting in a cathode block to a burner, not shown here.

The elongated, axially extending electrode body 2 is made in a preferred embodiment of copper. However, materials such as silver or copper alloys are also possible.

The electrode body 2 has an open and a closed end, with the closed end located in the lower area.

In the lower area, the electrode body 2 an inwardly extending receptacle 5 on. In the middle of the electrode body 2 is a hole 8th present and serves to accommodate the electrode core 9 , The hole 8th can be designed either as a blind hole or through hole.

The electrode core 9 is pressed in a preferred embodiment. Here, the invention is not limited to a press fit. It is also a soldering, welding or other connection technology possible. The recording 5 for the electrode core 9 is in the interior of the electrode body 2 formed radially and forms a part with the electrode body 2 out.

The electrode core 9 is designed as an insert and consists of a material with high thermionic emissivity. For this purpose, z. As hafnium, zirconium or tungsten can be used. The electrode core extends axially from the lower end through the bore 5 in the direction of the interior of the electrode body 2 ,

In the interior of the electrode body 2 extends the axial absorption 5 , wherein an annular recess 6 between the recording 5 and the housing wall of the electrode body 2 formed. The annular recess 6 serves for better circulation of the cooling liquid and thus allows a more effective heat dissipation away from the electrode.

The into the central center bore of the electrode body 2 used cooling tube 3 is thin-walled, hollow, cylindrical and preferably exchangeable.

Due to its diameter, the cooling tube forms 3 in its interior a fluid channel 4 out. The outer diameter of the cooling tube 3 is formed so that it returns a reflux of the cooling liquid between the inner wall of the electrode body 2 and the outer wall of the cooling tube 3 is made possible by a radial annular gap. Thus, a circulation of the cooling liquid takes place within the electrode body 2 instead of.

Due to the design of the cooling tube 3 the coolant is passing through the fluid channel 4 initiated and meets the electrode core 8th as well as the recording 5 with its inner surface 7 , Thereafter, the cooling liquid flows along the receptacle 5 in the annular recess 6 and is due to the formation of the electrode body 2 deflected into the radially outer annular space.

The circulation or deflection of the cooling liquid in the annular recess 6 requires some axial positioning of the cooling tube 3 opposite the electrode body 2 , This is inventively by at least one stop 10 achieved in the annular recess of the electrode body 2 located. According to the 6 is a stop 10 on the bottom of the annular recess 6 drawn, with more attacks 10 ' may be present, which are therefore drawn by dashed lines.

In a preferred embodiment, the stop 10 formed as an axial, rectangular elevation and spaced, due to its design and position, the cooling tube 3 in the lower region of the electrode body 2 , The stop 10 is therefore on the bottom-side end face of the annular recess 6 from the material of the electrode body 2 educated. The cooling tube is then with its front face on this stop 10 on.

Next to the rectangular shape of the stop 10 should be claimed for the present invention any other form, the side of the electrode body 2 is trained.

2 shows a second embodiment of the plasma electrode. Here, the same reference numerals as in 1 ,

New to this embodiment is that the stop 10a on the radial outside of the annular recess 6 of the electrode body 2 located. The stop 10a is thus directed radially inward with its longitudinal extent.

In 3 a third embodiment is shown. Here is the stop 10b on the radial inside of the annular recess 6 of the electrode body 2 , The stop 10b is thus directed with its longitudinal extent radially outward.

Crucial in all embodiments is that the number of attacks 10 . 10 ' . 10a . 10b . 10c not limited to one, as can multiple attacks 10 . 10 ' . 10a . 10b . 10c distance limiting for the cooling pipe 3 in the electrode body 2 in its circumferential annulus 6 be arranged.

4 shows a schematic representation of a plasma electrode 1 with an axial stop at the front 10c on the outer surface of the receptacle 5 of the electrode body 2 , Hiebei becomes the stop 10c both from the front side of the electrode body and from the inner wall of the recording 5 educated.

5 shows a schematic representation of a plasma electrode 1 with an axial stop at the front 10d on the electrode body 2 , Hiebei becomes the stop 10d both from the front side of the electrode body and from the outer wall of the recording 5 educated.

In 6 the electrode body is shown in the plan view of the central center bore. The view shows the central, inner fluid channel 4 , Between the electrode body 2 and the centric, inner receptacle 5 is the annular recess 6 , in a preferred embodiment is in the annular recess 6 in an axial direction in the liquid channel 4 pointing, raised stop 10 educated.

In a further embodiment, several stops 10 in the annular recess 6 shown. In the 6 dashed lines are drawn.

7 shows a ring 11 , which as a further embodiment a stop 10 for the cooling tube 3 should form. The ring 11 has at least one stop tooth 12 and is between the cooling tube 3 and the electrode body 2 used. In the illustrated embodiment are two diametrically opposed stop teeth 12 shown.

When installed, you can use the ring 11 and the stop tooth 12 the cooling tube 3 in alignment with the electrode body 2 be positioned in the axial direction. This allows a circulation of the liquid between the front end side of the cooling tube 3 and the electrode body 2 , wherein the annular recess 6 the direction reversal of the coolant flow accomplished.

8th shows a representation of a ring with two radial, internal attacks.

LIST OF REFERENCE NUMBERS

1

plasma electrode

2

electrode body

3

cooling pipe

4

liquid channel

5

Recording (lower area)

6

recess

7

palm

8th

drilling

9

electrode core

10

attack

11

ring

12

stop tooth

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

• EP 2082622 [0009]

Claims (10)

Plasma electrode ( 1 ) for a cutting device which consists of an electrode body ( 2 ) with an axial, central receptacle ( 5 ) for a front side deputed electrode core ( 8th ), wherein in the interior of the electrode body ( 2 ) flows a cooling liquid flow in the axial direction through at least one radially outer annular gap, and a radially inner liquid channel through an exchangeable cooling tube ( 3 ) formed by one or more stops on the electrode body ( 2 ) and its front, the electrode core ( 9 ) nearest end face in an annular recess ( 6 ) of the electrode body ( 2 ) engages, in which the cooling liquid flow is deflected, characterized in that on the inside of the electrode body ( 2 ) at least one stop ( 10 . 10a - 10d . 12 ) for the cooling tube ( 3 ) is arranged, which with the front end side of the cooling tube ( 3 ) cooperates. Plasma electrode ( 1 ) according to claim 1, characterized in that the at least one stop ( 10 . 10a - 10d . 12 ) the end stop for the cooling tube ( 3 ). Plasma electrode ( 1 ) according to claim 1 or 2, characterized in that the stop ( 10 . 10a - 10d . 12 ) in the recess ( 6 ) of the electrode body ( 2 ) is arranged. Plasma electrode ( 1 ) according to one of claims 1 to 3, characterized in that in the recess ( 6 ) of the electrode body ( 2 ) several attacks ( 10 . 10a - 10d . 12 ) are arranged. Plasma electrode ( 1 ) according to one of claims 1 to 4, characterized in that the at least one stop ( 10 ) at the bottom of the recess ( 6 ) is arranged in the electrode body. Plasma electrode ( 1 ) according to one of claims 1 to 5, characterized in that the at least one stop ( 10 ) at the bottom of the recess ( 6 ) is formed freestanding in the axial direction. Plasma electrode ( 1 ) according to one of claims 1 to 6, characterized in that the at least one stop ( 10 ) at the bottom of the recess ( 6 ) with at least one side surface with the electrode body ( 2 ) connected is. Plasma electrode ( 1 ) according to one of claims 1 to 7, characterized in that the at least one stop ( 10a . 10b . 10c . 10d ) directed with its longitudinal extent radially on the inner or outer wall of the electrode body ( 2 ) is arranged. Plasma electrode ( 1 ) according to one of claims 1 to 8, characterized in that the at least one stop in the form of at least one stop tooth ( 12 ) on a ring ( 11 ) is arranged in the recess ( 6 ) in the electrode body ( 2 ) is inserted. Plasma electrode ( 1 ) according to claim 9, characterized in that the stop tooth ( 12 ) on the ring either axially ( 7 ) or radial ( 8th ) is aligned.

Images