AU6090190A

AU6090190A - Process for automatically sealing in thermally sprayed surfaces

Info

Publication number: AU6090190A
Application number: AU60901/90A
Authority: AU
Inventors: Johann Stocker
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 1989-08-10
Filing date: 1990-08-10
Publication date: 1991-02-14
Anticipated expiration: 2010-08-10
Also published as: ATE121801T1; PT94962A; DE4024586A1; EP0412510B1; AU630998B2; EP0412510A1; BR9003932A; DE59008957D1

Abstract

A process for the automatic melting of thermally sprayed surfaces is proposed, in which the disadvantages of known processes of this type (manual and semiautomatic melting) are overcome. This is achieved by a method in which a parameter relevant for the melting process is measured using a non-contact sensor system on a part of the area which has just been subjected to the melting process by a melting burner and, starting from this measured value, the amount, which in fact may be dependent on the material thickness, type and form, is suitably controlled.

Description

COMMONWEALTH OF AUSTRALI' 89/68-AU

PATENTS ACT 1952 DECLARATION IN SUPPORT OF CONVENTION OR NON-CONVENTION APPLICATION FOR A PATENT

In support of the Application made for a patent for an invention Insert title of invention. entitled: Process for automatically sealing in thermally sprayed surfaces We, Dr. Wolfgang Nauth Insert full name(s) and address(es) of declarant(s) being the appli- -We (Senior Coroorate Counsel) cant(s) or person(s) authorized to sign on behalf of an applicant Dr. Gerhard Schaefer company. (General Patent Counsel) Linde Aktiengesellschaft, of Abraham-Lincoln-Strasse 21, D-6200 Wiesbaden, Federal Republic of Germany Cross out whichever of paragraphs do solemnly and sincerely declare as follows:- l(a) or 1(b) does not apply

1(a) relates to application made 1. the appliant by individual(s) We re l(b) relates to application made or(b) rm authorized by LINDE AKTIENGESELLSCHAFT by company; insert name of applicant company.

Cross out whichever of pragraphs the for the patent to make this declaration on behalf. 2ta) or 2(b) does not apply 21a) relates to application made 2. c ctlur of th .e.ntion by Inventor(s) We arc 2(t) relates to application made or(b) Johann STOCKER, of Mfinchner Torweg 13, by company(s) or person(s) who D-8031 Gilching, Fed. Republic of Germany are not inventor(s); insert full nne(s) and addres(es) of inven. <OT.

is the actual of the invention and the facts upon which the i entitled to make the application are as follows

State manner in which applicant(s) The applicant is entitled to make the derive title from Inventor(s) application on the bases of the employee's inventions law, whereby the applicant would, if a patent were granted upon an application made by the said actual inventor, be entitled to have the patent assigned to it. Crou out paragraphs 3 and 4 3. The basic application.. as defined by Section 141 of the ct "r made for, non-convention applications. iFo convention applications, in on the naert basic country(s) followed Linde Aktiengesellschaft by date(s) and basic applicant(s). in Germany on the August..l .1989 by Linde Aktiengesellschaft in on the

4 The basic application.. referred to in paragraph 3 of this Declaration J*a were the first applicationS....... madein a Convention country in respect of the invention the subject of the application Insert place and date of signature Declared atH riegels- this 22nd dayof November, 1990 kreuth LINDE AKTIENGE ELLSCHAFT Signature of declarant(s) (no aitestation required)

Note Inittal all alterations ppa. ppa. Dr. Nauth Dr. Schae er DAVIE-S COLLISON. MELBOURNE and CANBERRA.

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(12) PATENT ABSTRACT (11) Document No. AU-A-60901/90 (19) AUSTRALIAN PATENT OFFICE

(54) Title PROCESS FOR AUTOMATICALLY SEALING IN THERMALLY SPRAYED SURFACES International Patent Classification(s) 5 (51) B05D 003/08 C23C 004/18 (21) Application No. 60901/90 (22) Application Date 10.08.90 Priority Data (31) Number (32) Date (33) Country 3926420 10.08.89 DE FEDERAL REPUBLIC OF GERMANY 4024586 02.08.90 DE FEDERAL REPUBLIC OF GERMANY (43) Publication Date: 14.02.91 (71) Applicant(s) LINDE AKTIENGESELLSCHAFT (72) Inventor(s) JOHANN STOCKER (74) Attorney or Agent DAVIES COLLISON, 1 Little Collins Street, MELBOURNE VIC 3000 (57) Claim 1. A process for automatically sealing in a thermally sprayed surface on a workpiece, characterized in that a value which is relevant to the sealing-in process is measured by means of a non-contacting sensor mechanism on at least part of the area of the workpiece which is being subjected to the sealing-in process by means of a sealing in burner, the rate of advance which may be dependent on the thickness, type and shape of the workpiece being controlled in a suitable manner as a result of this measured value.

19.A sealing-in installation for carrying out the process according to one of claims 9 to 18, i.e. for rotationally symmetrical workpieces, characterized by a clamping device for the workpiece by means of which it can be set in rotation about its main axis, a carriage which can be displaced in the direc- tion of advance and provided with fastening means or a supporting arm on which the sealing-in burner and the sensor mechanism can be fastened,

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(11)60901/90 -2- a controllable drive motor for.this carriage, which displaces the carriage at speed values that can be fed to it and a control unit connected to the sensor mechanism and the drive motor for the carriage in order to regu- late the advance.

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COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

i NAME ADDRESS OF APPLICANT: i~j ii Linde Aktiengesellschaft Abraham-Lincoln-Strasse 21 D-6200 Wiesbaden :ii Federal Republic of Germany

NAME(S) OF INVENTOR(S): i .i Johann STOCKER

il ADDRESS FOR SERVICE:

DAVIES COLLISON Patent Attorneys i 1 Little Collins Street, Melbourne, 3000.

I11 COMPLETE SPECIFICATION FOR THE INVENTION ENTITLED: 1 Process for automatically sealing in thermally sprayed surfaces

The following statement is a full description of this invention, including the best method of performing it known to me/us:- first apP 4he lation made in a Convention country in respect ot tne Itsl v (he first applcation of the application day of November, 1990 H8llriegels- this 22nd 'A at kreuth LINDE AKTIENGESELLSCHAFT net plcendaDeclared

Signatare of declaant(s) (no a e e altestation required) ppa.N h S r Dr Nauth Dr. Schae er DAVIES ('OLLISON. MELBOURNE and eANBERRA.

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The present invention relates to a process for automatically sealing in a thermally sprayed surface on a workpiece.

With thermally sprayed surfaces, it is to some extent pos- sible to improve or modify the properties of the applied coatings by a subsequent operation, called sealing in. This operation consists in heating the so-called self-fluxing plead. material, constituted by self-fluxing spraying powders, o 10 above its solidus point temperature until it is sealed in. ataf By metallurgic reaction this operation results in an a integral bonding between the spraying material and the sub- strate, similar to hard soldering. The thus obtained o coatings are homogeneous, gas-tight and liquid-tight. Depending on the material uped, the required operating tem- perature ranges between 1020 and 1200 0 C.

o* In principle, two sealing-in processes are known: t

Firstly, it is known to carry out the sealing-in process o° manually, i.e. all manipulations,process management and process control are carried out by the sealing operator. The so-called "wet shine" a phenomenon which occurs above a certain heating point of the sprayed-on layer and which gives the impression that the workpiece is wet forms the criterion for judging the sealing-in process. However, this process places a heavy strain on sealing personnel because of the heat and the high level of attention and alertness.

Secondly, there are mechanized processes which operate on the basis that the sealing operator determines process para- meters (rate of feed, distance of sealing burner, etc.) beforehand and that these parameters are firmly set on a sealing-in installation for a certain type or workplace before the sealing-in installation carries out the sealing in process automatically but without any kind of individual inspection of the evolving sealing-in process. This again requires the presence of the sealing operator.

Consequently, the known processes present considerable dis- advantages.

The object of the present invention is, therefore, to pro- 4i vide a sealing-in process which avoids these disadvantages, which is capable of being automated to a great extent, which operates flawlessly, which is simple to use, sturdy and economically justifiable.

According to the invention, this object is achieved in that a value which is relevant to the sealing-in process is measured by means of a non-contacting sensor mechanism on at Sleast part of the area of the workpiece which is being sub- jected to the sealing-in process by means of a sealing-in Sburner, the rate of advance which may be dependent on the .thickness, type and shape of the workpiece being con- Sitrolled in a suitable manner as a result of this measured value.

An appropriate and advantageous value which is measured as

being relevant to the sealing-in process is the temperature i in the sealing-in range. It is measured by means of a pyro- meter, i.e. by means of a non-contacting temperature measuring device.

A likewise advantageous alternative consists in measuring the increased reflectivity of the surface area which has just been treated, the so-called wet shine, as the value which is relevant to the sealing-in process, by means of a reflected light detector.

By means of the process according to the invention, there is proposed a procedure which can be automated, with all the elements required for this purpose being provided, and which provides a sealing-in process that is individually con- trolled for each distinct workpiece.

To carry out the process with a pyrometer, the optical range thereof within the sealing-in zone is advantageously envisaged to be of a distance greater than 30 cm, while the pyrometer must be calibrated to a temperature range which is suitable for the sealing-in process, and while optionally a shield to guard the pyrometer against heat may be provided.

When a reflected light detector is used as the sensor mecha- Snism, the reflected light detector can be advantageously S arranged, on the one hand, perpendicularly above the surface to be measured, with the result that, in accordance with the principle of reflection, reflected light will fall back into the detector, whereby the advance rate is controlled in association with the emergence of the wet shine and the resulting control signal.

S, 20 On the other hand, it is also possible to employ the reflec- i ted light detetor by disposing it at a slight angle above the surface to be measured, with the result that initially, j with the surface being dull, diffuse reflected light is incident in the light detector and, upon emergence of the wet shine, this diffuse reflected light decreases, whereby the advance rate is controlled in association with the resultant control signal.

In principle, there are several options as regards the move- ments or sequence of motions for the workpiece, the sealing in burner and the sensor mechanism. First of all, there is a fundamental difference between substantially planar, flat workpieces and more or less round, at least approximately rotationally symmetrical workpieces.

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In the case of planar workpieces, a first advantageous coor- dination of movements consists in moving the sensor mecha- nism and the sealing-in burner periodically above the sur- face to be treated, the sealing-in burner and the sensor mechanism being moved in parallel, i.e. with the same orien- tation and with identical sequence of motions, with the advance being superimposed on the cyclic movement. SiI I Another favourable variant is to give the sensor mechanism Sand the sealing-in burner a parallel orientation while the S 10 workpiece is moved cyclically and treated as it advances.

i' In the case of rotationally symmetrical workpieces, it is advantageous to set the workpiece in rotation about its main j axis and to orient the sensor mechanism and the sealing-in S burner in such a manner that they treat or scan the same 15 cylindrical surface circle and the advance is parallel to 1 the workpiece axis.

,Further advantageous embodiments, which are however more expensive, consist in rapid periodic scanning of the work- piece by the sensor mechanism, resulting in continually updated surface images which are utilized to control the advance, or in providing a plurality of sensor mechanisms adjacent or above one another, thus creating a delicate con- trol signal on the basis of which the advance is determined.

SIf workpieces are not perfectly flat or cylindrical, an S 25 advantageous manner of carrying out the process consists in moving the burner such that the distance between workpiece and burner remains constant. In this way, all surface areas of the workpiece are subjected in similar fashion to the burner flame and to thermal energy.

In a further, improved variant embodiment, the speed of the processing movement, e.g. the rotational speed, is varied as a function of the shape of the workpiece, namely such that each part of the workpiece will pass the flame at a constant speed.

I A fuel gas and oxygen gas burner, preferably operating with i acetylene and oxygen, is advantageously used for the sealing in process according to the present invention. Acetylene- i oxygen operation in particular provides the possibility to regulate a flame with a neutral to reducing action and at the same time with high heat output, in order to obtain, for Sexample by means of a reducing flame, an oxide-free surface S10 in the sealing-in phase. fti

In a further advantageous development, the burner is S equipped with means to regulate the amount of gas, which can be controlled as a function of the given geometry of the Sworkpiece, the temperature of the workpiece or the sealing condition.

A burner provided with means for controlling the burner and Si the flame, which is thus monitored with respect to gas j supply, temperature and flame, allows the integration of i safety elements such as, for example, automatic switch- off in the event of malfunctioning of the burner.

In a variant of the invention which should be indicated specifically, all the essential process parameters are S entered into a central programmable computer and control unit, these values being transformed by said unit into a suitable sealing-in procedure which is also monitored and i controlled by said central unit.

Advantageously, this computer and control unit automatically records all essential data.

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A sealing-in installation for carrying out the process according to the invention for rotationally symmetrical workpieces comprises S- a means for clamping the workpiece by means of which it can be set in rotation about its main axis, I a carriage which can be displaced in the direction of advance and provided with fastening means or a supporting arm on which the sealing-in burner and the sensor mecha- i nism can be fastened, a controllable drive motor for this carriage, which dis- places the carriage at speed values that can be fed to it, a control unit connected to the sensor mechanism and the drive motor for the carriage in order to regulate the advance.

Advantageously, there is provided a central, programmable computer and control unit which is connected to the drive motor for the carriage, the burner, the sensor mechanism and Sthe rotary motor, into which unit the data relevant to the j 20 procedure can be entered and which determines the data rele- Svant to the procedure and controls the procedure.

The carriage may advantageously also be designed to be dis- placeable transversely to the direction of advance, because this provides an additional degree of freedom of movement for the burner and the sensor mechanism, which results in an improved guidance of these elements in relation to the workpiece surface, especially in the case of non-cylindrical workpieces.

It is also advantageous to so design the sealing-in instal- lation that the sealing-in burner can be moved forwards and backwards and that its flame orientation is different from the 900 orientation relative to the workpiece axis and has a slightly inclined orientation. The workpiece area subjected to the flame is moved slightly by a forward or backward movement, which may result in an optimum design of the sealing-in process, for example owing to the fact that later heat development which is no longer detected by the sensor mechanism is prevented.

The thermal stress on the entire installation can be reduced by the arrangement of heat shields in the region under and to the sides of the clamped in workpiece.

The process according to the invention will be explained in S greater detail hereinbelow by way of example with reference 10 to diagrammatic drawings.

Fig. 1 shows an arrangement for sealing in a thermally sprayed-on surface on a shaft 1 (rotationally symmetrical!). A reflected light detector 2 and a sealing-in burner 3 with its fuel gas and oxygen supply acetylene and oxy- gen) are arranged above the cylindrical surface of the work- piece 1, at the same height and facing each other, i.e. in this case offset by 1800. The reflected light detector 2 is connected to a control unit 5 which processes the output signal of the reflected light detector 2. The control unit is further connected to an advance motor 6 which drives the feed carriage 8 via a transmission element 7. Both the 1, sealing-in burner 3 and the reflected light detector 2 are mounted on the feed carriage 8. The lines 9 indicate the zone in which the wet shine occurs.

In order to carry out the process according to the invention, the workpiece 1 is set into rotation and the sealing- in burner 3 is actuated. Thus, the cylindrical surface circle disposed underneath the direction of action of the burner 3 is heated, as a result of which the wet shine phenomenon occurs after a certain temperature (slightly exceeding 1000 0 C) is reached. The increase in reflected light is then recorded at the reflected light detector 2 which is arranged on the opposite side of the shaft 1 above the surface of the latter, it is converted into a correspon- ding signal and transmitted to the control unit 5. As a function of its programming, the control unit triggers the actuation of the advance motor at a certain signal value and at a certain basic speed, which depends essentially on the dimensions of the workpiece (approximately 4 to 20 cm/min for a workpiece diameter of about 6 cm). Thus, the feed car- riage 8 is set into motion via the transmission element 7, and the burner 3 and the reflected light detector 2 are dis- placed together along the surface to be treated. The reflec- ted light detector 2 continuously monitors whether a 09r$

S suitable workpiece temperature is reached, as this is asso- ciated with the occurrence of the wet shine. When the amount o~ ,15 of reflected light decreases, the control unit ensures that o s the rate of advance is reduced.

In another programming variant, for example, an advance step is triggered upon the emergence of the wet shine, which cor- responds substantially to the width that can be treated by the burner flame at any one time.

Fig. 2 shows the overall construction of another variant of a sealing-in installation according to the invention. A workpiece 10 which is rotationally symmetrical, but not cylindrical and which tapers in longitudinal direction 5 towards its centre is clamped by means of a clamping device 11, consisting of a clamping carriage 12, a locating pin 13 with a clamping arbor 14 and an opposing arbor 15. As a result of the clamping force, the workpiece can be set into rotation via the arbor 15 by means of an adjustable drive mechanism disposed in the housing 16. Parallel to the axis of rotation and arranged at a lower level than the latter, there is provided a rail 17 on which is disposed a carriage 18 with a supporting arm 19 mounted thereon. A sealing-in burner 20 as well as a pyrometer 21 for the non-contacting measurement of the surface temperature are fastened to the supporting arm 19, both of these components being oriented i toward the cylindrical surface of the rotationally symme- I trical workpiece while being offset by about 90 A motor l in association with a drive shaft 26, rollers 27 and 5 V-belts 28 ensures the movement of the supporting arm 19 parallel to the axis of rotation 30. By way of the connec- i ting line 31 between the advance motor 25 and a central Scomputer and control unit 33 as well as by way of additional i signal lines 32, all the essential process data and para- meters and all necessary control signals between the various components and the central computer and control unit 33 are transmitted. In the example under discussion, the computer i and control unit is so designed that all sequences, move- ments and parameters can be entered and adjustments in advance rate and rotation as well as monitoring functions i can be performed.

In this regard, Fig. 3 shows a diagram of the connections that exist in the device to be described below.

The following data must be entered for a specified sequence i 20 of motions:

S- starting point, trajectory, end point rotational speed for the working spindle parameters for the adjustment of advance in longitudinal I direction corresponding to the temperature signal

As the rotational speed, positioning and adjustment of iadvance are dependent on the workpiece, it must be possible for the operating personnel to change these parameters. As far as the sequence of motions is concerned, this can be done in the so-called teach-in process, i.e. by travelling over the envisaged trajectory while recording the essential coordinate points, or alternatively by means of a purely theoretical determination and subsequent entry of the coor- dinates. As regards the advance temperature adjustment, the

_I I i following parameters in particular must be programmed in: required temperature lower and upper limit temperature for alarm signals as well as the values determining the control performance.

These data are advantageously called up automatically by the operator by means of a menu-operated program. The installa- tion according to the invention must basically allow the following operating conditions: o 0

De. 10 a) manual operation S° b) teach-in entry of coordinates c) entry of computed coordinates o d) entry of parameters i 0 0 e) test run and f) automatic operation corresponding to current data.

In more detail: 6 04

In manual operation individual functions such as, for example, actuation of the burner, rotation of the working spindle or displacement of the advance carriage or certain burner settings can be performed. The teach-in process can be utilized to particular advantage with this manual opera- S tion, because in this way the empirically obtained informa- tion of the manual sealing-in process can be used to program the ulterior operating procedure. This concerns the rota- tional speed, the burner distance, the burner position, in other words the movement path of the burner in general, and possibly also the inclined positioning of the burner and the distance of the pyrometer. On the other hand, in the general entry state, the entry of all data through figures is possible, for example with the aid of an existing diagram, thus providing an alternative to the teach-in process. In test mode, it is possible to first perform a test run for a t

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I sealing-in process which may be followed, if necessary after Ssome corrections, by purely automatic operation.

A possible production procedure is as follows:

a flame-sprayed workpiece is clamped in

the rotational movement is started the burner is moved to a starting point and ignited upon passage thereof burner and pyrometer are moved to the starting point for the sealing-in process the surface temperature is measured even during the heating-up phase and the advance is started when the Srequired temperature is reached the advance is adjusted in accordance with the invention i and moves along the predetermined path of the burner tip upon reaching the end position of the sealing-in process, the burner is withdrawn from the workpiece and optionally extinguished., S- finally, the burner is returned to the starting position, while the workpiece is exchanged manually or by means of a workpiece exchanging device either beforehand, at the same time or afterwards.

SWith respect to the method of regulation there is, as can be seen in Fig. 3, a networking of the individual elements of the installation such that the pyrometer provides a tempe- rature signal which is transmitted to the control unit, Swhich in turn computes the necessary advance values from i this value and implements these on the programmed advance Spath. In addition, the computer and control unit is connec- ted to the ignition burner, the sealing-in burner and the burner control means, so that if necessary, in the event of variations from the predetermined required values, it is possible to readjust these elements or to stop the sealing in process. The process according to the invention as well as the associated devices provide numerous possible embodi-

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ments and variations in details. In principle, relatively simple variants of the process according to the invention are just as feasible as the above-described complex network of a wide variety of functional elements with the trans- mission of many measuring signals to a central unit and the control of different elements by the latter. In contrast thereto is the comparatively simple version of the invention according to Fig. 1.

Summarizing, however, it can be stated that, with the proce- dure according to the present invention, the sealing- in process for a coating sprayed onto a workpiece can be automated in various stages of perfection. Good quality results are obtained when the proposed process is carried out expertly, with the automatic procedure taking place very reliably and without constant monitoring by qualified personnel.

Claims

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THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

I 1. A process for automatically sealing in a thermally sprayed surface on a workpiece, characterized in that a value which is relevant to the sealing-in process is measured by means of a non-contacting sensor mechanism on Sat least part of the area of the workpiece which is being subjected to the sealing-in process by means of a sealing in burner, the rate of advance which may be dependent on the thickness, type and shape of the workpiece S 10 being controlled in a suitable manner as a result of this Smeasured value.

2. A process according to claim 1, characterized in that the temperature is measured as the value which is relevant to the sealing-in process, by means of a pyrometer.

3. A process according to claim 1, characterized in that the increased reflectivity of the surface which has just been treated, the so-called wet shine, is measured as the I value which is relevant to the sealing-in process, by means of a reflected light detector.

S 20 4. A process according to claim 2, characterized in that the 1 optical range of the pyrometer covers an area within the i sealing-in zone which is envisaged to be of a distance i greater than 30 cm, while the pyrometer is calibrated to *i a temperature range which is suitable for the sealing-in process, and while optionally a shield to guard the pyro- Smeter against heat may be provided.

5. A process according to claim 3, characterized in that the reflected light detector is arranged above the surface to be measured vertically with the result that, according to the principle of reflection, reflected light falls back into the detector, whereby the advance is controlled in association with the emergence of the wet shine and the resultant control signal.

I.I aiu ana that these parameters are firmly set on a sealing-in installation for a certain type or workpl-ce before the sealing-in installation carries out the sealing

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6. A process according to claim 3, characterized in that the reflected light detector is arranged above the surface to be measured at a slight angle, with the result that ini- tially, with the surface being dull, diffuse reflected light is incident in the light detector and, upon emer- gence of the shine, this diffuse reflected light wet decreases, whereby the advance is controlled in associa- tion with the resultant control signal.

7. A process according to one of claims 1 to 6, character- ized in that the sensor mechanism and the sealing- 0 4 in burner are moved periodically above the surface to be treated, with the sealing-in burner and the sensor mecha- nism being moved in parallel, i.e. with the same orien- tation and with identical sequence of motions, with the advance being superimposed on the cyclic movement.

8. A process according to one of claims 1 to 6, character- ized in that the sensor mechanism and the sealing- in burner are oriented in parallel and the workpiece is moved cyclically and treated as it advances.

9. A process according to one of claims 1 to 6 for rota- tionally symmetrical workpieces, characterized in that i the workpiece is set in rotation about its main axis and the sensor mechanism and the sealing-in burner are oriented such that they treat or scan the same cylindri- ii 25 cal surface circle upon rotation of the workpiece and the advance is parallel to the workpiece axis.

process according to one of claims 1 to 6, character- f ized in that only the sensor mechanism periodically scans the workpiece, which results in continually updated sur- face images which are utiliszed to control the advance. face

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11.A process according to one of claims 1 to 6, character- ized in that a plurality of sensor mechanisms are pro- vided adjacent or above one another, thus creating a delicate control signal on the basis of which the advance is determined.

12.A process according to one of claims 1 to 11, character- ized in that the burner is moved such that the distance between workpiece and burner remains constant.

13.A process according to one of claims 1 to 12, character- ized in that the speed of the processing movement, e.g. the rotational speed, is varied as a function of the shape of the workpiece, namely such that a constant passing speed is obtained.

14.A process according to one of claims 1 to 13, character- 15 ized in that fuel gas-oxygen burner, preferably an a acetylene-oxygen burner, is used as the sealing-in burner.

i 15.A process according to claim 14, characterized in that the burner is equipped with means to regulate the amount of gas, which can be controlled as a function of the given geometry of the workpiece, the temperature of the workpiece or the sealing condition.

16.A process according to one of claims 14 to 15, charac- terized in that the burner is equipped with means for i controlling the burner and the flame, and is thus moni- tored with respect to gas supply, temperature and flame.

17.A process according to one of claims 1 to 16, character- ized in that all the essential process parameters are entered into a central programmable computer and control unit, these values being transformed by said unit into a suitable sealing-in procedure which is also monitored and controlled by said central unit.

fundamental difference between substantially planar, flat workpieces and more or less round, at least approximately rotationally symmetrical workpieces.

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18.A process according to claim 17, characterized in that all essential data are recorded by means of the central computer and control unit.

i 19.A sealing-in installation for carrying out the process according to one of claims 9 to 18, i.e. for rotationally I symmetrical workpieces, characterized by I a clamping device for the workpiece by means r of which it can be set in rotation about its main axis, a carriage which can be displaced in the direc- i 10 tion of advance and provided with fastening means or a Ssupporting arm on which the sealing-in burner Sand the sensor mechanism can be fastened, S- a controllable drive motor for this carriage, Swhich displaces the carriage at speed values that can be fed to it and a control unit connected to the sensor mechanism and the drive motor for the carriage in order to regu- late the advance.

installation according to claim 19, characterized by a S 20 central, programmable computer and control unit which is j; connected to the drive motor for the carriage, the burner, I the sensor mechanism and the rotary motor, into which I unit the data relevant to the procedure can be entered and which determines the dependent data relevant to the S 25 procedure and controls the procedure.

S21.An installation according to claim 19 or 20, character- if ized in that the carriage is also designed to be dis- -r placeable transversely to the direction of advance.

22.An installation according to one of claims 19 to 21, characterized in that the sealing-in burner can be moved forwards and backwards and that its flame orientation is different from the 90 orientation relative to the work- piece axis and has a slightly inclind orientation relative to the advance.

.U In a further, improved variant emboament, tne speea or tne processing movement, e.g. the rotational speed, is varied as a function of the shape of the workpiece, namely such

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23.An installation according to one of claims 19 to 22, characterized in that heat shields are arranged in the region under and to the sides of the clamped in workpiece.

24. A process for automatically sealing in a thermally sprayed surface and/or an installation for achieving same substantially as hereinbefore described with reference to the drawings.

The steps, features, compositions and compounds disclosed herein or referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more of said steps or features.

DATED this TENTH day of AUGUST 1990

Linde Aktiengesellschaft

by DAVIES COLLISON Patent Attorneys for the applicant(s)

i I tne u orientation relative to the workpiece axis and has a slightly inclined orientation. The workpiece area subjected to the flame is moved slightly by a forward or backward

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I .L CL k_ t L C r LI Lt: Ittpcu CL UUL Ilg r[I U-y exceeding 10000C) is reached. The increase in reflected light is then recorded at the reflected light detector 2 -q nrr:Yx~-ut-.urF.~urrr~ara)- -OI V~q~i; .i uni wnicn is aisposed a carriage 18 with a supporting arm 19 mounted thereon. A sealing-in burner 20 as well as a pyrometer 21 for the non-contacting measurement of the surface temperature are fastened to the 81 0 ,1 ii U 0 I -U P