EP0338222B1 - Device for coating the inside of cylindrical hollow bodies - Google Patents

Description

The invention relates to a device for coating the inner surfaces of cylindrical hollow bodies with a rotary head for distributing the coating material under the effect of centrifugal force, the coating material leaving the rotary head through openings pointing radially outward.

A device of the type mentioned at the beginning is shown, for example, in the publication US Pat. No. 3,044,441. The device is intended for coating with a material consisting of two components. The device shows a rotating spray head that can be driven by an air motor. It can be adjusted in the longitudinal direction of the cavity to be coated with the aid of a stationary electrical drive device and cannot be used anywhere. A device for spraying a liquid coating composition onto the inner wall of a tubular workpiece with the aid of compressed air is shown in the document CH-A-571 365. In this, a coating composition jet, which is initially directed in the axial direction of the workpiece, is sprayed by a perpendicularly rotating air jet to form a spray cone deflected in the radial direction. This type of coating is only possible with material within an advantageous viscosity range. The coating according to CH-A-541 365 cannot be used to coat internal pipe threads with conventional lubricating grease.

AT-PS 383 053 describes a device for applying coatings to the inner surfaces of preferably cylindrical hollow bodies, in particular lubricating and / or anti-corrosion greases on the inner surfaces of screwed sockets with a rotating body which can be inserted into the hollow body to be coated and which has a drive is connected to rotate about an axis parallel to the axis of the hollow body to be coated. The known device shows a closed rotary body with a cavity in which a feed line for the coating agent opens. Through a radially outward-pointing outlet slot provided in the peripheral surface of the rotary body, the coating agent leaves the rotary body under the action of centrifugal force and strikes the inner surface of the hollow body to be coated which surrounds it. The rotating body is held adjustable at least in the direction of its axis of rotation and possibly also transversely to it. An electric motor, which is equipped with a transmission gear, serves to drive the rotating body and can be moved with the rotary body itself on a fixedly arranged carriage in the longitudinal direction of the rotational axis of rotation. With the known device, the inner surfaces of sleeves can be coated, which are attached to pipes mounted on the floor. After the coating has been finished, however, it is necessary to protect the inner surfaces in order to prevent the coated surfaces from being subsequently contaminated again by the accumulation of dust. Contaminated grease is not suitable for the proper lubrication of threads and can lead to costly defects when the pipes prepared in this way are screwed together. This can only be remedied by additional measures in the form of protective caps which are placed or screwed onto the ends of the hollow bodies after the coating process. This involves considerable additional costs. Another possibility is to carry out the coating process immediately before joining the hollow bodies, for example pipes on a drilling rig, with which an earth hole is to be lined. However, a device according to the Austrian patent specification is completely unsuitable for use on a derrick. That is why, for example, the internal threads of the pipe sockets could only be greased on site by hand. The fat was applied with a fat brush, whereby uneven and too thick layers of fat could not be avoided. The disadvantages caused by this are considerable. If the application is too thin, the interlocking threads can seize. If the layers of fat are too thick, grease is squeezed out of the threads during the screwing process. It falls down the pipe string and gradually leads to the accumulation of large quantities at the lower end of the pipe string. Sensitive measuring devices, which are lowered to the lower end after the completion of the strand, are not able to function properly due to the contamination to work. Excessive grease in the threads also hampers a proper test procedure to check the gas tightness of the pipe connection. Leakage gas produced in very small quantities is prevented from flowing out by an excessively thick layer of grease between the threads and cannot be detected by the sensors of the measuring devices. A gas tightness is simulated, which is often not available. The consequences can be serious. Escaping leakage gas can collect in underground caverns and possibly lead to explosion accidents. The material required for greasing is usually in a container, the lid of which is removed and not put back on after every greasing process. Dust, partly mixed with larger particles, can contaminate the uppermost layers of fat again and again.

The object of the invention is to provide a device according to the generic term mentioned above, with which the difficulties mentioned can be eliminated. In particular, the device should be suitable for use on a derrick, i. H. it must be handy and able to work reliably. At the same time, it must comply with the safety regulations that apply to operation at the derrick.

The invention as a solution to this problem is characterized in that the rotary head is driven by a compressed air motor and can be moved in the longitudinal direction of the hollow body to be coated by at least one compressed air operated actuating cylinder, in that the rotary head is arranged with the compressed air motor within a housing which has detachable connections for flexible supply lines of a supply unit for compressed air and the coating material is connected and that the compressed air motor carries the rotary head at the free end of its drive shaft and is attached with its end remote from the rotary head to a lifting carriage which is guided on guide rods inside the housing, one inside the housing adjustable stop plate for the lifting carriage is arranged.

Further features that advantageously shape the subject matter of the invention are specified in the subclaims.

The device can be placed by hand on the free end of a pipe sleeve and operated by operating a switch be set. After the limit switch has responded, it is removed by hand. The speeds and the feed speed as well as the supply of the quantities of the coating material can be controlled by means of suitable pneumatically acting control elements, for example throttle valves, so that the layer thickness can be adapted to the respective requirements which are determined by the pipes. The associated storage container for the grease remains closed and thus protected against the ingress of dust. The use of compressed air as work equipment and only pneumatically acting control elements excludes any risk of explosion. It is therefore suitable for use on drilling rigs. It is also characterized by a technically simple training. To coat, for example, the internal thread of a pipe sleeve with grease, the device with the centering sleeve is placed on a pipe sleeve. The compressed air motor is started by the operating switch and at the same time the coating material, for example threaded grease, is fed via the supply line and the associated rigid end part to the rotating head rotating at high speeds. Through small openings, not shown, in the jacket of the rotary head, the grease emerges radially from the rotary head under the action of centrifugal force and finely coats all threads, since the motor with the rotary head is simultaneously fed through the actuation of the actuating cylinder. As soon as the rotary head has reached its outer end position, the air motor is switched off by a limit switch, which can work, for example, depending on the time. At the same time, the feed is ended. The piston in the cylinder is pushed into its starting position under the action of a counter pressure, since it is designed to be double-acting, with the lifting slide, the drive motor attached to it and with the rotary head. The coating process is finished and the device can be lifted off the pipe sleeve.

In the drawing is an embodiment of the invention shown schematically and explained below.

Fig. 1

die Gesamtansicht der Vorrichtung mit der Versorgungseinheit,

Fig. 2

einen Längsschnitt durch die Vorrichtung,

Fig. 3

einen weiteren Längsschnitt senkrecht zu dem Schnitt gemäß Fig. 2,

Fig. 4

einen weiteren Längsschnitt unter einem Winkel von etwa 30° zur Darstellung gemäß Fig. 2,

Fig. 5

die Draufsicht auf die anschlußseitige Stirnseite des Vorrichtungsgehäuses,

Fig. 6

einen Querschnitt durch die Vorrichtung gemäß Fig. 3 oberhalb der Führungszylinder in ihrer obersten Einstellung,

Fig. 7

einen Querschnitt durch die Vorrichtung gemäß Fig. 4 und

Fig. 8

eine Schaltungsanordnung für das Inbetriebsetzen, Abschalten und Regeln des Arbeitsablaufs einer Vorrichtung.

Show it:

Fig. 1

the overall view of the device with the supply unit,

Fig. 2

a longitudinal section through the device,

Fig. 3

2 shows a further longitudinal section perpendicular to the section according to FIG. 2,

Fig. 4

2 shows a further longitudinal section at an angle of approximately 30 ° to the representation according to FIG. 2,

Fig. 5

the top view of the connection-side end face of the device housing,

Fig. 6

3 shows a cross section through the device according to FIG. 3 above the guide cylinder in its uppermost setting,

Fig. 7

a cross section through the device of FIG. 4 and

Fig. 8

a circuit arrangement for commissioning, switching off and controlling the workflow of a device.

The entire device consists of the coating device 1 and the supply unit 2. The device for coating is surrounded by a housing 3, which has a connection 4 for the supply lines combined in a strand 5 is provided. A centering sleeve 6 is arranged on the end of the housing opposite the connection 4 for the supply lines, with which the coating device can be placed on a pipe sleeve 7 of a pipe 8. The supply line 5 leads to the supply unit 2, consisting of a pneumatic control system 9 and a container 10 for the supply of coating material and the pressing device with which the coating material is conveyed via the supply line 5 to the coating device.

In the housing 3, a lifting carriage 11 is arranged to be movable in the longitudinal direction of the housing. It carries guide sleeves 12a and 12b which are firmly connected to the lifting slide by means of screws 13. The guide sleeves and the slide are penetrated by guide rods 14a, 14b, on which the lifting slide with its guide sleeves can slide and is guided. The guide rods are screwed to the front housing covers 15 and 16. For this purpose, they are provided with threads 17 at their ends. Screw nuts 18 are used for fixing. The housing cover 15 on the connection side is provided with openings 19 for this purpose, while the housing cover 16 is equipped with threaded bushings 20 on the opposite side. This ensures easy installation.

At least one actuating cylinder 21, which is fastened to the connection-side housing cover 15 by means of a screw nut 22 and a threaded attachment 23, is used to drive the slide. The free end of the piston rod 24 which can be extended from the cylinder is fixedly connected to the lifting slide by means of a screw nut 25 and a threaded shoulder 26.

A drive motor 27 operated with compressed air is attached to the slide 11 and carries a rotary head 29 at the free end of its drive shaft 28, which has the shape of an open on one side Vessel shows in which the free end 30 of the supply line 31 extends for the coating material. This part of the supply line is rigid and is held and supported at a constant distance from the drive motor 27. The supply line 31 in the area between the lifting carriage and the connection-side end of the housing can be designed as a flexible hose in order to be able to follow the movement of the lifting carriage.
A screw coupling, not shown, provides the connection between the rigid free end 30 of the supply line and the flexible tubular part 31. At the same time, the supply line is thereby firmly connected to the lifting slide. A similar screw connection 34 is provided for the attachment of the flexible supply line 35 with the drive motor.

The drive motor 27 leaves the interior of the housing 3 through the feed together with the rotary head 29 through an opening 36 in the housing cover 16. The centering sleeve 6 is flanged to this and fastened with the aid of screws 37 which engage in threaded bushings 38 of the housing cover 16.

The connection-side housing cover 15 is held by tabs 75 fastened to the housing 3. The motor 27 is fastened to the lifting slide 11 with the aid of a holding block 73. The mounting screws are labeled 74. To limit the stroke of the lifting carriage 11, a stop plate 71 is provided within the housing, which can be adjusted in the longitudinal direction of the housing with the aid of a threaded spindle 72. For this purpose, a cross handle 172 is provided at the outer end of the threaded spindle. With its inner end, the threaded spindle is mounted on a ball 173 in a bore in the housing cover 16.

To change the viscosity of the coating material, for example To be able to reduce grease, the device can additionally be provided with a heater 70 which can be placed, for example, on the connection-side end face. The coating material passes the heater on its way to the rotary head and is heated.

For handling, the housing 3 is equipped with handles 103, which can be screwed on, for example. With their help, the device can be plugged onto a pipe sleeve, the thread of which is to be sprayed with grease, for example.

Compressed air passes from a compressor 40 (not shown in more detail) via a connection 41 and the supply lines 41a, 41b and 41c (FIG. 8) to the two consumers, namely to the drive motor 27 and to the actuating cylinder 21. In the supply line 41 there is a maintenance unit for air conditioning, consisting of a filter 42, a pressure reducer 43 and an oiler 44 used. 45 shows a pipe coupling seen in the direction of flow behind the maintenance unit.

Control lines 46 branch off from the supply lines for a manually operable operating switch 47 (2/3 directional valve) with a start button 147 and a shuttle valve 48 in the supply lines 41a and 49 for a limit switch 50 for decommissioning the device. The limit switch 50 is provided with a swivel lever 51 which, when the slide stroke ends, strikes the stop plate or against which the piston rod 21c of the actuating piston 21d (FIG. 8) moves at the end of its advance and thus actuates the limit switch 50. A control line 52 for actuating a valve 53 branches off from the supply line 41b for advancing the actuating piston, which valve releases the supply of the coating material to the rotary head 29. 54 is a pump for the coating material and 55 its reservoir.

The cross section of the supply line 41b for the advance of the actuating piston 21d can be shut off or shut off by a shuttle valve 56. closable. The valve is controlled via a control line 57 which branches off from the supply line 41a of the drive motor. A throttle 58 for volume control and a downstream buffer 59 are inserted into this control line, as a result of which the switching movement of the spring-loaded valve 56 is delayed. Throttles for regulating the volume and thus the speed of the movements of the actuating piston 21d are inserted into the supply lines 41b and 41c. They have the reference numbers 60 and 61.

Before the device is started up, operating pressure is present via the supply line 41a upstream of the shuttle valve 48, via the supply line 41b upstream of the shut-off valve 56 and via the supply line 41c in the actuating cylinder 21 at the rear of the actuating piston 21d. By actuating the operating switch 47, the shuttle valve 48 is switched through, so that the drive motor 27 is started. Due to the time delay elements, throttle 58 and buffer 59, the shut-off valve 56 is switched somewhat delayed. The compressed air enters the actuating cylinder 21 and acts on the front of the piston 21d. Due to the difference in area of the piston, it is moved in the feed direction. The compressed air from the rear of the actuating piston is pressed back into the supply line 41. The flow rate is limited by the throttle 61.

As soon as the piston rod 21c reaches the switching pin 51 of the limit switch 50 and switches it, the cross section of the control line 49 is released. The operating pressure of the control line, in which a throttle 62 acting as a timing element is also arranged, switches the shuttle valve 48 into the blocking position and leads to the venting of the part of the supply line 41a which is between the shuttle valve 48 and the drive motor 27 is through the vent hole of the shuttle valve. At the same time, the control line 57 is vented.
The spring-loaded shut-off valve 56 can thereby close and at the same time vents the part of the supply line 41b located between this valve and the actuating cylinder 21. The operating pressure constantly present in the supply line 41c immediately begins to push the actuating piston 21d back into its starting position. During the feed movement of the actuating piston 21, the operating pressure via the control line 52 ensures that the valve 53 is switched, so that coating material can be pressed from its reservoir 55 via the pump 54 into the feed line 63 to the rotary head of the device, not shown. After the shut-off movement of the valve 56, the control line 52 is also vented via the vent hole of the valve. The valve 53 can thereby switch back into its blocking position and prevent the further supply of coating material to the rotary head.

Claims (19)

1. A device for coating the inner surfaces of hollow cylindrical members, having a rotary head (29) for the distribution of the coating material by the effect of centrifugal force, the coating material leaving the rotary head (29) through radially outwardly directed openings, characterized in that the rotary head (29) is driven by a compressed air motor (27) and can be moved by at least one compressed-air-actuating adjusting cylinder (21) in the longitudinal direction of the hollow member to be coated; the rotary head (29) together with the compressed air motor (27) is disposed inside a casing (3) which is connected to releasable connections (4) for flexible supply lines (31,35) of a supply unit (2) for compressed air and the coating material; and the compressed air motor bears the rotary head at the free end of its driving shaft and is attached by its end remote from the rotary head to a carriage (11) guided on guide rods (14a,14b) inside the casing, an adjustable stop plate (71) for the carriage (11) being disposed inside the casing.
2. An apparatus according to Claim 1, characterized in that the piston rod (24) of the adjusting cylinder (21) is rigidly connected to the carriage, while the adjusting cylinder is rigidly connected to the cover (15) of the casing.
3. An apparatus according to Claim 1 or 2, characterized in that attached to the carriage (11) are guide cylinders (12a,12b) through which the guide rods (14a,14b) extend.
4. An apparatus according to one of Claims 1 to 3, characterized in that the rotary head takes the form of a vessel which is open on one side and into which the free end (30) of the supply line (31) for the coating material extends.
5. An apparatus according to one of Claims 1 to 4, characterized in that the supply line for the coating material is rigid in the zone between the carriage and the rotary head and is screwed to the carriage, and a hose (31) forming part of the supply line which extends to the supply unit is attached to the screwed connection.
6. An apparatus according to one of Claims 1 to 5, characterized in that the whole supply line (35) for the drive motor of the rotary head is disposed inside the casing and takes the form of a hose.
7. An apparatus according to one of Claims 1 to 6, characterized in that the rotary head and the motor can be moved outwards through an opening (36) in the casing cover (16) adjacent said members.
8. An apparatus according to one of Claims 1 to 7, characterized in that flanged to the casing is a centring sleeve (6) by which the device can be placed on a hollow member to be coated.
9. An apparatus according to one of Claims 1 to 8, characterized in that the casing has two handles (103) for respectively fitting the device onto and removing the device from a hollow member.
10. An apparatus according to one of Claims 1 to 9, characterized in that the compressed air supply for the axial advance of the rotary head can be cut off by a limit switch (50).
11. An apparatus according to one of Claims 1 to 10, characterized in that the compressed air supply for the drive motor of the rotary head can be controlled by an adjustable throttle valve (64).
12. An apparatus according to one of Claims 1 to 11, characterized in that the supply unit consists of a compressor (9) and a compressed-air-driven press (10) for the coating material, these two members being attached to a common transportable frame (40).
13. An apparatus according to one of Claims 1 to 12, characterized in that the limit switch used is a timedependent switch.
14. A device according to one or more of Claims 1 to 13, characterized in that all the control members are constructed to act pneumatically.
15. A device according to one or more of Claims 1 to 14, characterized in that the casing is releasably connected to a heater (70) for changing the viscosity of the coating material.
16. A device according to Claim 1, characterized in that the stop plate can be adjusted in the longitudinal direction of the casing (3) by a threaded spindle (72).
17. A device according to one or more of Claims 1 to 16, characterized in that the drive motor is screwed to a retaining block (73) attached by means of retaining screws (74) to the carriage (11).
18. A device according to one or more of Claims 1 to 17, characterized in that the casing cover (15) is attached to the connection side of the casing via retaining straps (75) which are directed radially inwards, starting from the generated surface of the casing.
19. A device according to Claim 18, characterized in that the guide rods (14) engage through both the connection side casing cover (15) and also its retaining straps (75) and are screwed jointly to said elements.

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