Pipe-coating machine



Aug. 22, 1939. G. D. WILLIAMS PIPE-COATING MACHINE 5 Sheets-Sheet l Filed Dec. 14, 1936 ATTORNEY. Aug- 22 1939@ G. D. WILLIAMS 2,170,314 PIPE-COATING MACHINE Filed Dec. 14, 1936 5 Sheets-Sheet 2 Q-Qatg FIE E ATTORNEY. Ii/ i2 54 Aug. 22, 1939. G. D. w|| L.|AMs PIPE-comma MACHINE 5 Sheets-Sheet 3 Filed Dec. 14, 1936 Aug. 22, 1939. G. D. WILLIAMS 2,170,314 PIPE-COATING MACHINE Filed Dec. 14, 1936 5 Sheets-Sheet 4 y my fv @w my Aw my my my my Av Aw my AW AW' 7g /02 /0/ INVENTOR. feo/*ge MOY/@m75 ATTORNEY. Aug. 22, 1939. G. D. WILLIAMS PIPE-COMING MACHINE Filed Dec. 14, 1936 5 Sheets-Sheet 5 ww mw L ww w ATTORNEY. Patented Aug. 22, 1939 I UNITED lSTATES PATENT OFFICE PIPE-COATING MACHINE of California Application December 14, 1936, Serial No. 115,740 6 Claims. This invention relates generally to machines for applying protective coatings to the inner surface of metal pipes or conduits. It has particular application to coating materials which are heated at the time of application, as for example so-called asphaltic or coal tar enamels or like products. It is an object of the present invention to improve upon machines, of the above character in certain respects, including the followingz-To afford a latitude of flexibility and adjustment with respect to the size of pipe being handled by the machine, whereby the machine can be adjusted to suit various requirements; to afford a novel :mechanism for rotating the pipe, whereby large size pipe can be smoothly rotated at suiiicient speed to retain the coating material against the inner walls of the pipe by centrifugal force; to make possible application of molten asphaltlc enamel to form a smooth layer of the requisite thickness, without cracks or porosity; and to afford a superior type of applicator, to deliver the hot asphaltic enamel in the form of a uniform sheet to the inner surface of the pipe, thus making it possible to obtain the type of coating desired. Further features and objects of the invention will appear' from the following description in which the preferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawings. Referring to the drawings: j Fig. 1 is a side elevational view, illustrating diagrammatically a complete machine incorporating the present invention, with a pipe applied to the same. Fig. 2 is a plan view of the right hand portion of the machine illustrated in Fig. 1, but on an enlarged scale, and with the pipe removed. Fig. 3 is a plan view ofthe left hand portion of the machine as shown in Fig. 1, on the same scale as Fig. 2, whereby Figs. 2 and 3, when taken in conjunction with each other, form an enlarged plan view of the complete machine. Fig. 4 is a cross-sectional detail taken along the line 4-4 of Fig. 3. f" ' Fig. 5 is a cross-sectional detail taken along Fig. 8 is a cross-sectional detail taken along the line 8--8 of Fig. 2. Fig. 9 is a detail showing the applicator for the y coating material, and which is carried at the free end of the boom. Fig. 10 is a cross-sectional detail taken along the line IIJ- I0 of Fig. 9. Fig. 11 is a cross-sectio-nal detail taken along the line II-II of Fig. 10. Referring first to Fig. 1,*the invention consists generally of a carriage I0, which operates upon the track II. Extending from the carriage I0 there is a horizontal boom I2, the free end of which carries an applicator I3. By means of suitable feed mechanism the carriage can be advanced along the track at a definite rate, whereby the applicator I3 is advanced longitudinally' within the pipe I4, during application of the coating. The pipe I4 is carried by mechanism whereby it can be spun or revolved at a relatively high speed, during the coating operation. Assurning that the coating material being applied is a coal tar product, which must be heated to an elevated temperature to make it iiuid, the carriage I 0 supports a kettle, which contains a batchof the enamel, and which is maintained at an elevated temperature. From this kettle the iiuld coating material is applied by means of a pump and piping, to the applicator I3. The carriage I'Il which has been illustrated, consists of a frame or body 2|, (Fig. 7) Vhaving flanged wheels 22 which engage the track rails Il. The so-called boom I2, can be conveniently formed from an H-structural beam (Fig. 6) which has its one end portion suitably anchored to the carriage body 2|. The sides of this beam are shown enclosed by the upper and lower cover plates 24, thereby forming two passages 26, extending longitudinally of the boom. As will be presently explained these passages serve to house piping, through which the coating material is supplied to the applicator. In order to more adequately sustain the boom in horizontal position, intermediate points are shown connected to the cables 21 and 28, which connect back to the frame 29, mounted upon the carriage. Also mounted upon the body2l of the carriage, there is a supporting frame work 3|, which serves to carry' a kettle or container 32. Immediately below the kettle 32 there is a suitable form of fire box 33, to which a ilame or hot gases can be applied from a suitable gas or oil burner. For removing molten coating material from the kettle 32, there is a suitable. pump 34, having its inlet connected to the bottom of the kettle through (Figs. 6 and 9). pipe 36, and its outlet connected to the discharge pipe 31. Pipe 31 extends through the lower compartment 26 of the boom (Fig. 6) to finally connect with the tting 38, at the free end of the boom. (Fig. 9). Fitting 33 is connected through the cross-fitting 39, to the final discharge pipe 40, and also to the return pipe 4|, which extends back through the boom through the upper passage 26. On the carriage, pipe 4| connects with the bottom of the kettle 32 (Fig. 7). The connection to pipe fitting 39 is controlled by a suitable valve (Fig. 9) whereby supply of the. coating material to the applicator i3, can be turned on and oi. Likewise a valve 44 in pipe line 4| is provided, whereby during periods when valve 43 is open to supply coating material to the applicator I3, valve 44 can be closed, to reduce the rate of return of the material back to the kettle. These two valves are preferably connected for unison operation, by means of a sliding connecting rod 45. To prevent loss of heat and undue cooling of the hot liquid coating material, the inner Walls of the passages 26 are shown covered with suitable heat insulating material 46 Pump 34 can be of the positive displacement type, driven by suitable means such as an electric motor 41, and is also positioned in the re box, whereby it is heated. To maintain the coating material being circulated through pipes 31 and 4I at a desired elevated temperature, suitable electrical heating elements 50 are disposed along the length of structure l2 and within the compartments 26. The means for moving the carriage l0 at a controlled rate, makes use of an endless chain 5| (Figs. 3 and 5). This chain extends longitudinally between the track rails l l, and the upper and lower runs of the chain are supported within suitable structural channels 52 and 53. These channels are carried by suitable brackets 54, which in turn are carried by the foundation of the machine. They may be provided with wood liners 56, to minimize friction. That end of the chain which is remote from the pipe I4, is shown engaged over a sprocket 51 (Figs. 3 and 4), which in turn is provided. with a suitable mounting 58, to a part of the machine foundation. A supplemental idler sprocket 59 is also provided, in order to more adequately guide the lower run through the lower supporting channel 53. The other end of the endless chain 5| engages a similar sprocket 6|, which is mounted upon the drive shaft 62. Through suitable mechanical drive elements, shaft 62 is driven by the electric motor 63. The elements of this drive means need not be described in detail, except to note that it includes a speed reducing gear train 64, and a reversing clutch 66, whereby for one position of this clutch shaft 62 is rotated in one direction at a relatively slow rate, While for the other position of the clutch shaft 62 is reversed and driven at a much faster rate. The gear train 64 is preferably of the type enabling a graduated control over the speed with which the shaft 62 is driven. The lower side of the carriage body 2| is provided with a depending bracket 1| (Fig. 7) which is attached to the upper run of the endless chain 5|. Therefore the carriage moves together with this endless chain, at a relatively slow rate in one direction, corresponding to the direction of movement While coating material is being applied to the pipe, and at a relatively -greater rateV of speed in the opposite direction to remove the boom and tatpplicator from the pipe, after a coating operaion. 14, which carry the rollers or wheels 16 and 11. These rollers are provided with resilient rubber treads, to minimize noise and vibration. sired the bearings for these rollers can be positioned at different points along the beams 14, in order to accommodate pipes of widely varying diameters. The rollers 11 are connected to be driven by an electric motor 18, through a suitable two-speed driving gear 19. Briefly, this drive gear includes a drive chain 80, directly connecting the shafts 8| of rollers 11, for unison rotation. The motor 18 connects through counter shafts 82 and 83, to drive two loose sprockets 84 and 85, on one of the shafts 8|.- Sprocket 84 is driven at a relatively high speed, while sprocket 85 is driven at a slow speed. Clutch element 86 serves to clutch either one of these driven sprockets, with the corresponding shaft 8 whereby the rollers 11 are driven at a relatively high speed, or at a slow speed, depending upon the position of the clutch element. When a pipe section resting upon rollers is rotated, it tends to creep in a longitudinal direction. Also, if the speed of rotation is suicient, it tends to chatter and bounce upon the supporting rollers. In order to avoid longitudinal creepage, rollers 9| and 92 are provided, for engaging the ends of the pipe. Roller 9| is shown journalled upon a suitable supporting bracket 93, which in turn can be permanently mounted to a fixed part of the machine. Roller 92 is shown carried by the journal bracket 94, which is slidably carried by the guide track 96. A fluid pressure actuator 91 has its operating rod 98 connected to the journal bracket 94. Therefore by means of pneumatic pressure applied to the actuator 91, roller 92 can be retracted to facilitate removal and application of pipe, or advanced to engage the end of the pipe, and thus prevent longitudinal creepage of the pipe as it rotates. In order to enable rotation of the pipe at high speed, without chattering, flexible endless cables |0| are provided (Figs. 1, 2 and 8) which engage the end portions of the pipe. Each exible cable |0| engages a pair of sheaves |02 and |013, which can be mounted between the adjacent structural beams 14. One of these sheaves, as for example sheave |02, can have a xed journalled connection to the beams 14, while the journal for the other sheave |03, is shown connected to the operating rod |04 of the fluid pressure actuator |06. Thus by pneumatic pressure applied through the actuator |06, each sheave |03 can be urged outwardly to yieldably tension the associated endless cable |0I, and thus firmly hold down the adjacent end portion of the pipe, while at the same time enabling rotation of the pipe at high speed. By releasing the tension upon cables |0I, they can be readily disengaged from the ends of the pipe. The details of the applicator I3 can be best understood by reference to Figs. 9 to 11 inclusive. It is in the form of a box made of sheet metal, with its lower walls |01 and |08 inclined toward each other V-fashion. The end Walls |09 are secured to the lower walls |01 and |08, and are also attached to the ends of a top wall I.' A baiile wall ||2 extends between the end walls |09, and is adjustably attached to the top wall III by bolts II3. The bailie I I2 in eiect divides the interior of the box into two compartments II4 and'I I5, whichy are in communication'below the lower edge II6 of the bailie II2. Compartment II4 is provided with an inlet opening II1, connecting with the supply pipe 40. From compartment II5 coa-ting material may be naily discharged over a lip or weir II8, which is in` the form 'of a plate extending between the end walls -I 09, and adjustably attached to the lower walls |01. It should be noted particularly that lip I I8 is at an elevation above the lower edge II6 of baiile II2, In order to better distribute the relatively viscous coating material as it is introduced into compartment II4, through inlet II'I, a plurality coating material ows downwardly and under the baffle |I2. it is finally discharged as a uniform sheet over the entire length of lip II8. The lower part of the applicator box can be provided with a removable plug |22, to facilitate drainage. Also carried by the applicator, there is a depending exible curtain |23. made of suitable material such as leather or heavy cloth. When the applicator is in operative position with respect to the pipe I4, the lower edge of the curtain |23 is in close proximity to the pipe. The purpose of this curtain is to interrupt swirling air currents which are set up during operation of the machine, due to rapid rotation of the pipe. With this curtain itis possible to maintain a' uniform sheet of coating material being discharged over the lip IIB. Otherwise the sheet of coating material might be occasionally or continually interrupted by air currents, to the detriment of the coating being applied. Operation of the complete machinev can now be reviewed as followsz-A pipe to be coated is placed upon the rollers I6 and TI, and the holddown cable IIII is applied to the end of the same. At this time the carriage III is at its far position from the pipe, so that the boom I2 does not interfere with the handling of the pipe. Kettle 32 contains a proper charge of coating material, such as a coal tar enamel. and this material is at a proper temperature to be applied. Also pipes 31 and 4I have been heated and are maintained at a suitable elevatedtemperature, by the elec` trical heating unit 50. The pump 34 is maintained in operation, and the valve 43 and 44 are turned in such direction that although coating material is not supplied to the applicator I3, it is continuously circulated through the pipes 31 and 4I. Assuming that the pipe being handled is made of ordinary sheet steel. which is generally not vperfectly cylindrical, and which (particularly in the larger sizes) tends to spring or give in a lateral direction, a suitable re-inforcement should be supplied. as for example collapsible stiffening rings |26, which can be applied to the ends of the pipe. The carriage I0 is now moved towards the pipe I4, until the applicator I3 is positioned at appproximately the point erated to supply the coating material to the applicator I3, and clutch 66 is operated to progress the carriage I0 at a definite rate towards the pipe. The rate of advancement of the carriage is so correlated with the speed of rotation of the pipe, that in effect a ribbon coating material is applied spirally. The coating material has sufcient viscosity vthat while it spreads to a slight extent upon the inner surface of the pipe, it can be retained as a coating` of considerable depth. After the entire interior of the pipe has cen coated, the supply of coating material to applicator I3 is interrupted, and by reversing the position of clutch 66. the carriage is rapidly moved in an opposite direction to retract the boom I2 and the applicator I3. Rotation of the pipe may be continued for a time, to insure a proper setting of the coating. 'l If desired the speed of rotation can now be decreased, by changing the setting of clutch 86. When the coating has properly set or hardened, further rotation is interrupted, endless cables IIlI are removed, the end thrust roller 92 retracted, and the pipe removed, to make place for a new pipe to be coated, During the coating operation the speed of rotation must of course be such as to retain the coating material, under centrifugal force, on the' Likewise rotation inner surfaces ofthe pipe. must be relatively smooth, without chattering, in order to insure a smooth application. Hold-down cables IIJI insure smooth Vspinning or rotation at the requisite speed, and the features of the applicator described, make possible application of an uninterrupted sheet of the coating material, so that the nal coating is a continuous and impervious protective layer. that the applicator may progress in either direction, during a coating operation, by suitable modication of the driving means for the carriage. I claim: 1. In a machine of the character described, rollers adapted to rotatably engage the lower segmental portion of a pipe section, with the axis of the pipe in horizontal position, an endless cable engaging over the upper side of the pipe, and spaced sheaves engaging said cable and serving to tension the same to hold down the pipe upon the pulleys, one of said sheaves being movable to enable release and removal of said cable. 2. In a pipe coating machine of the character described, means for rotatably supporting a pipe in horizontal position, a horizontal track extending parallel to the axis of the pipe, a carriage operating -on the track, a boom mounted on the carriage, the free end of the boom being movable into the pipe 'by movement of the carriage, an applicator carried by the free e'nd of the boom, a kettle for containing coating material mounted upon the carriage, means for heating said kettle, 'a pump having itsinlet connected to the kettle, a pipeserving to connect the discharge side of the pump to said applicator, and a return pipe having one end of the same connected to said discharge `pipe near said applicator, and extending back to said kettle. 3. In a machine of 4the character described, an applicator for coating material comprising a ybox having an inlet opening and also a horizontal lip over which the coating material is discharged, and a wall dividing vthe interior of the box in two connecting compartments, one compartment receiving the coating material from the inlet opening and the second compartment delivering the coating material over the discharge lip, said wall having a lower edge terminating at a level bellow It will be evident the level of the lip, the compartments being in communication below said wall. 4. In a machine of lthe character described, an applicator for coating material comprising a box having an inlet opening, and also having a horizontal lip over which the coating material is discharged, a Wall serving to divide the interior of the box into two connecting compartments, one compartment receiving the coating material from the inlet opening, and the second compartment delivering the coating material over the discharge lip, said wall having a lower edge terminating at a level below the level of the lip, the compartments being in communication below said edge, and means including baille elements mounted in the first compartment and serving to laterally distribute viscous material introduced through said inlet. 5. In a machine of the character described, rollers serving to rotatably support a section of pipe in a horizontal position, endless cables looped over said pipe, and means serving to tension said cables and also serving to hold the pipe down upon the rollers without interfering with rotation of the pipe, said last means including sheaves disposed below the axis of said pipe and over which said cables are entrained. 6. In a pipe coating machine of the character described, means for rotatably supporting a pipe in a horizontal position, a horizontal track disposed exterior of the pipe and extending parallel to the axis ofv the pipe, a carriage operating on the track, a :boom mounted upon the carriage, the free end of the boom being movable into one end of the pipe by movement of the carriage, a coating material applicator mounted upon the free end of the boom, a container for coating material mounted upon the carriage, means mounted upon the carriage for heating the coating material, piping extending from the container along the boom to the applicator and also extending from the applicator back to the container, a pair of valves associated with the piping, one valve located near the applicator and the other located near the carriage, and common means for simultaneously opening and closing said valves `Whereby coating material can be delivered to said applicator or can be circulated through said piping back to the container. GEORGE D. WILLIAMS.



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Cited By (3)

    Publication numberPublication dateAssigneeTitle
    US-3024130-AMarch 06, 1962Dresser IndProcess of bonding a bituminous enamel protective coating to a suitable base such asmetallic pipes and pipe couplings
    US-3878815-AApril 22, 1975Pont A MoussonConstant-flow spray-gun coating machine
    US-4704985-ANovember 10, 1987Nordson CorporationSpray gun mover