US3374766A - External pipe and tube coating apparatus - Google Patents

Description

March 196 8 J. w. WEAVER ETAL 3,374,766

EXTERNAL PIPE AND TUBE COATING APPARATUS Filed July 25, 1962 F/G. a

IN VENTORS JA CK w 1454 1/5? United States Patent Ofi ice 3,374,766 Patented Mar. 26, 1968 3,374,766 EXTERNAL PIPE AND TUBE COATING APPARATUS Jack W. Weaver, P.O. Box 1584 74101, and Barney L.

'Weaver, Jr., 5765 E. 30th Place 74114, both of Tulsa,

Okla.

Filed July 25, 1962, Ser. No. 212,401 5 Claims. (Cl. 118-6) This invention pertains to a novel apparatus for applying a coating of amterial, preferably of a thixotropic material, or the like, including resinous materials and high solid coatings, to the exterior surface of a pipe or tube. Heretofore in applying an exterior coating, other than cementitious materials, to a pipe or tube it has been generally necessary to use either a spraying technique, pour and wrap, or a spirally movable applicator going continuously around the pipe to wipe on the coating material, such as coal tar products and the like.

Throughout this application it is to be understood that the word thixotropic material means any material which lowers its viscosity under high sheer stress. For example, a container of coal tar epoxy in its static or quiescent condition has high viscosity. Upon adequate agitation of the thixotropic material, its viscosity is lowered sufliciently for application. The present invention employs linear motion between the pipe and the applicator to provide the necessary high sheer stress in the coating material within the applicator to obtain an optimum viscosity. A gauge means determines the thickness of the layer of coating material for a given linear velocity of the pipe or work piece. As the coated pipe emerges from the applicator gauge, elimination of the high sheer stress restores the coated material to its static or quiescent condition.

In none of the methods available is it possible to actually apply a single layer of coating material to a surface with said single layer of coating material being of the desired thickness. While spraying and wiping methods did put on several layers of coating material in a cut'andtry application, there has been no known method of using a single application of a final predetermined thickness other than merely applying multiple single applications or filmsor a mass layer which was controlled merely by the convolute wiping of the material until the approximate thickness was reached.

It is therefore an object of the present invention to employ a novel means for applying a linear controlled thickness layer of coating material to the exterior surface of a pipe or tube.

A further object of the invention is to provide a novel means of more rapidly applying a coating material of a predetermined final thickness layer in a single application.

Another feature or advantage of the invention is to apply linearly a single layer of coating material having a more uniform thickness, particularly when utilizing thixotropic materials.

Another advantage or object is to competitively be able to utilize more expensive and better coating materials because of the labor savings of the overall cost of the job.

A further benefit or advantage is to more readilyapply a thin or a thick layer utilizing a linear applicator technique with an adjustable thickness gauge to obtain the desired thickness of the coating with one linear pass of the applicator over the pipe to be coated.

The invention contemplates an elongated sleeve preferably having a flexible portion for example, rubber-like or other expandable material, with said sleeve fitting completely around the pipe to be coated. The pipe to be coated is positioned relative to the center of the coating sleeve or applicator to permit relative linear motion between the sleeve and the pipe. The coating material is fed into an enlarged portion of the applicator sleeve and as the pipe, for example, moves toward the opposite or smaller diameter or final gauging end of the sleeve, the bulk coating material applied to the pipe is gradually reduced in thickness as the pipe moves, in one form of the invention, until the pipe emerges from the final pneumatic controlled thickness gauge terminal portion of the sleeve at the desired dimension. The thickness gauges, in their various variable forms, may be pneumatically adjustable to compensate for variations in application techniques, or compensated for changes in viscosity or ambient temperatures, and other variables while working the material.

Various advantages, features, or objects of the invention have been set forth, yet it is to be understood that other objects, features and advantages may become apparent to those skilled in the art. It is to be understood that variations, changes, modifications and alterations may be made in the device as presented herein without departing from the basic concept of the invention. The form of the invention presented herein is to be considered as illustrative only and is not to be considered as limitations of the invention, as the basic concepts of the invention may be carried out in many ways, as indicated in the following specifications and drawings.

In the drawings:

FIGURE 1 is a side view, partially broken away, showing one form of the sleeve applicator being used in the process of coating a section of pipe.

FIGURE 2 is a front view of the device substantially as presented along lines 22 in FIGURE 1, with certain of the apparatus, such as the stand, trough and compressor being omitted for sake of clarity.

FIGURE 3 is a partial end view of a break-open or split type sleeve coupling for over-the-ditch operation.

Referring to the drawings, there is shown in FIGURE 1 a portion of a representative section of pipe 20 longitudinally disposed within a sleeve or applicator means 30 which applicator is carried longitudinally or axially of the pipe by a supporting structure 22 having a yoke including a base portion 23 and two opposed side portions 24, with each side portion having a U-shaped journal or hearing 25. A flat annular ring 26 preferably made of metal or other rigid material has a pair of pinions 27 and 28, respectively, secured on opposite sides thereof and disposed radially to engage their respective U-shaped bearings 25. The applicator sleeve is preferably, or at least in the form shown, an elongated flexible envelope or sleeve 3%, which has a larger diameter at the leading annular end 32 than at the gauge terminal exit end 34 which has a terminal peripheral end 38 which is the final portion of the applicator sleeve which touches the coating as the pipe to be coated moves through or relative to the applicator.

A flexible annular flange 40 is secured to the leading annular edge 32 and the flexible enlarged portion of the sleeve or applicator means 30 end has a radial inner and outer diameter substantially the same as the annular ring 26. The sleeve or applicator means 30 has a tapered portion which runs substantially from the annular end 32 to the area substantially at point 44 which is an approximate dimension or distance between the terminal peripheral end 38 and leading annular end 32. From the point 44 to the terminal end, the present showing represents the flexible sleeve as being basically cylindrical and of the same radial dimensions when in a static condition or when there is no relative motion between the pipe to be coated and the coating applicator.

The sleeve or applicator means 30 has the terminal peripheral end 38 disposed through the annular ring 26 so that the flange 40 is ultimately engaged with the annucertain material for coating the outer surface of pipe of smaller dimensions, generally in the' range of 1 to 3 or 4 inches. On pipe running from 4 to 12 inches in the outside diameter, the flexible sleeve material would preferably be of a. greater thickness or less flexible material to maintain its proper or desired shape and compressional characteristics during operation.

Ordinarily, in the arrangement shown, the supporting structure 22 not only includes the yoke with the side portions 24 and base portion 23, but a vertically disposed screw 46 which is secured to the base portion 23 of the yoke and is threadedly coupled with a stanchion 47 carried on a base 48. Collecting pan 50 is shown merely positioned lower than the sleeve or applicator means 30, but in actual operation the collecting'pan would preferably be a trough which would be located between the base portion 23 of the yoke and the annular flange of the sleeve 40. A liquid pump 52 has one end connected by a tube 53 with the pan 50 or trough for collecting or scavenging the residue coating material and pumping same through the riser pipe 55 which terminates in an outlet 56 to fill the reservoir 58. The outlet from the reservoir 58 is controlled by the spigot 60 having a control valve 61 which controls the flow of material on to the upper surface of the pipe 20 immediately adjacent the leading annular end 32 and the annular flange 40.

As the pipe 20 is moved to the left the coating material will build up on the upper surface thereof and flow down both sides of the pipe by gravity into the lower sleeve reservoir area 63. Upon movement of the pipe to be coated, to the left, as indicated by arrow 64, the thixotropic coating material will be urged from the reservoir cone portion 67 between the normally cylindrical portion' 66 of the sleeve, which is roughly between the terminal peripheral end 38 and the point 44 adjacent the cone portion 67 of the sleeve 30 and the pipe, toward the peripheral end 38 of the applicator sleeve 30. After the coating material flows in an annular layer between the cylindrical portion 66 and the rigid pipe, the flexible cylindrical portion 66 ordinarily will bulge outwardly :in annular form from adjacent the apex end of the cone portion 67 to a point farther to the left on the cylindrical portion 66, and tapers down to the inner dimension of the pneumatic or thickness control 70. The bulge which 7 is represented by a dotted line is indicated by reference numeral 68. This condition takes place substantially along the entire sleeve of flexible applicator material up to the gauge 70, and acts as a squeegee eifect to use the resilience of the flexible cone to tend to force the coating material out toward the reservoir area 63, while the coating material completely fills the area of bulge 68.

When in use, and under predetermined conditions with a coating material of a predetermined viscosity, the coating material will be deposited on the pipe and as the pipe leaves the terminal end 38 the coating material remaining on the pipe will be of the desired outside diameter.

Naturally, the characteristics of the flexible sleeve material will be considered and will have enough inherent compressional or resistive force to compress the coating material to the desired thickness.

While the sleeve or applicator means 30 has definite material characteristics for a particular viscosity and speed of linear motion of the application, there are many factors which would cause these conditions to change. When this is the case, a pressure controllable gauging means is used to establish or determine the ultimate thickness of the coating material supplied. 7

A coating material thickness gauge control 71) is shown 4 in one form as an'inflatable element which is somewhat oval in cross section, or may be said to have a flattened circular cross section and is positioned on the outside of the sleeve within the confines of the terminal peripheral end. A compressor 72 having a pressure gauge 74 is shown coupled to a valve 76 so that the pressure in the thickness gauge control 70 maybe varied to expand or compress the terminal exit end 34 of the sleeve 30 per 56 to obtain the desired thickness of final coating material for the particular operating conditions. In some instances, the thickness gauge control is secured, vulcanized or the like to the outer surface of the sleeve adjacent the terminal end 38 so that the cross-sectional shape ofthe thickness gauge control is pre-established; Naturally, the dimension of the thickness gauge control may be varied since the material from whichrit is made is resilient and may yield to both internal pressure from the coating ma:

terial and external gauge control pressures. While one thickness gauge control is shown in FIGURE 1, it is to be understood that several thickness gauge controls generally of the same type as 70 may be employed side by side on the outside of the sleeve. When this is done, ordinarily the gauges would be employed to provide a greater compressive force on the sleeve in definite axial areas so that the gauge means would progressively be used to thin out the coating material by the squeegee action to obtain a better control or more uniform thickness by permitting the last of the controls to be used to act upon a smaller thickness change. For example, if the job of coating permits a sleeve to be used without a special thickness gauge control 70, then the end result of pipe coating thickness is correct for a given relative coating speed for the particular viscosity of the coating. Normally, either with or without the use of the thickness gauge control 70, the terminal peripheral end 38 is'in engagement with the outer surface of the pipe to be coated when there is no relative motion between the applicator and the pipe. If the coating material to be employed has a high viscosity and would require appreciable pressure for a change of the coating thickness, then this can be controlled by (1) increasing the pressure in the pneumatic gauge, (2) increasing the thickness of the sleeve material, or (3) decreasing the relative speed between the sleeve and the pipe, or a combination of any of the three methods set forth.

Whilethe thickness gauge 70 has been shown merely as a tubular member, and internal pressure therein determines the thickness of the coating material, the thickness gauge may have an additional restrictive means not necessarily flexible, on the outside thereof so that'the fluid pressure within the thickness gauge may be more eifective under certain conditions. 7

While one form of sleeve or applicator'means is shown as being flexible, it is to be understood that the sleeve may be made also of metal, fiber, or other rigid material and have merely a terminal end sect-ion of 2 to 8 inches in axial length which would be of resilient or expandable material and of suitable dimensions for receiving a gauge means such as 70 or the like. One arrangement of the device has been made with a cone portion 67 of aluminum with the flange also being of aluminum and with a small cylindrical section extending axially in the area of bulge 68. A flexible sleeve having a certain resilient characteristic was employed on the terminal end.

While a closed or continuous circular portion of the sleeve is presented herein, in FIGURE 1, it is to be understood that in over-the-ditch operations where the pipe may be a line of one or more miles in length,'without a break therein, a split or break open sleeve (and gauge means) may be utilized having edges 84 and 85 substantially parallel with each other the length of the sleeve, and with an O-ring 86 utilized in between the edges as shown in FIGURE 3. In one arrangement a flexible bead also was used along the edge 84 in lieu of the O-ring. With the break open type arrangement, a linear projection of rubber 88 was used down the edge of the split in the sleeve and had clamps 89 pivoted to 90 with a tongue portion fitting in a complemental slot 92 for locking the sleeve in place for oVer-the-ditc application. With the latter arrangement the break-open sleeve can be put on or removed anywhere along the pipe. In the latter case, a break-open clamp with adjustment means was used to tighten a band on the outside for compression of the terminal end of the sleeve 38 to act as a removable thickness or gauge control 70.

The gauge control 70 or collar controls the dimension of the outer end of the flexible sleeve which in turn determines the thickness of the material applied for a given relative speed and viscosity. The tapered reservoir portion of the sleeve must be full at all times adjacent the cylindrical area and outlet end. The squeegee action of the applicator when in use allows coating material to expand the resilient sleeve so that the coating material is agitated within the sleeve in a type or kind of linear rolling action to thoroughly wet the pipe surface to achieve an adequate bond of the coating material to the pipe.

It may not be necessary to have the variable collar at the rear end of the sleeve at all times in order to maintain the particular coating thickness. It may be necessary to use the sleeve as is shown without an outside collar since the rear of the sleeve may be of such dimensions, for certain diameter of pipe that the variable collar would not be required. The inherent characteristics of the sleeve, per se, would be selected for the uniformity of a particular material having a certain viscosity.

The flexible sleeve basically will flex and slide over the outside surface of the pipe, including projections or indentations which vary from the nominal dimension of the pipe. The flexible sleeve material may be made of any suitable flexible substance, for example, urethane material has been extensively used as well as natural and synthetic rubbers. Other thermosetting and thermoplastic materials or other material that :will be and are being developed may be satisfactorily used in the construction of the sleeve. The sleeve may be made of one of several different materials, including flexible plastics, fibers, and the like. The controlled coating thickness is applied on the pipe Without runs or sags in the material and is brought about with this device by several features, including the formulation of the material. Certain characteristics are important such as the viscosity of the material, the temperature of the coating, the mixture of materials, the solvent condition of the coating material, if any, and the reaction or setting time, which is frequently referred to as the curing time. The relative speed of application of the coating on to the pipe is a factor that is considered when using the invention. The characteristics of the sleeve facilitate in determining the coating thickness.

The coating thickness is uniform because the gauge end of the flexible sleeve exerts inward pressure all around the annular layer of coating material, equally. The equally applied annular pressure on the coating material uniformly centers the sleeve on the pipe and provides a thickness of coating that is uniform. This equally inward annular pressure is important in conjunction with the linearly movable annular layer applicator, since any variation in the outside diameter of the pipe would alter the pressure accordingly in the pressure gauge means, and accordingly the sleeve on the :high spot area would move outwardly until the pressure, annularly, is balanced. The converse is true for a low spot. Consequently, the inherent characteristics of the device, particularly adjacent the final peripheral edge 38, automatically varies the coating thickness to compensate for deviation in the surface irregularities of the pipe. The uniformity of layer thickness is virtually constant.

The coating device or apparatus may be used overthe-d-itch, in the yard, or in the shop, in one of the various forms shown.

One form of the invention employs a drive means or feeding arrangement for feeding lengths or sections of pipe to be coated to the coating material applicator. Any form of conventional or convenient roller rack or table may be used to align and guide the pipe from a feeding source to the pipe support and pipe feeding arrangement. One form represented is shown having a plurality of feed rollers disposed as a part of or on a pipe supporting structure and feeding means, including a base or bases 100, with support bars 101 vertically positioned thereon carrying rollers, certain of which may be fee-d rollers 102 positioned to carry or at least friotionally engage the pipe or pipes to be coated and feed same through the coating material applicator. A drive motor or drive means 104 is operatively coupled by drive shafts 103 and 103' to the several feed rollers 102 and 102, which feed rollers are merely representative of a workpiece or pipe carrying and pipe feeding arrangement. Naturally the feed rollers, or guide rollers, or suitable guide means may be employed to adjustably axially align the pipe with the applicator longitudinal axis by lacing rollers in a Vaform, or any other conventional method, and may be adjustably movable up or down or left or right. A speed control is shown connected or coupled to the drive means 104 for varying or adjustably controlling the rate of feed of the pipe through the applicator by the motor or feed means. The linear rate of feed, such as feet per minute of pipe through the applicator for a given layer thickness, will be determined by the characteristics of the coating material employed for the particular coating job.

The coating material is fed at a controlled rate to the upper surface of the pipe so that the coating material will be relatively moved within the applicator to be fed to the applicator gauge means for disposition on the pipe. One or several feed control means for the coating material may be appropriately positioned and controlled to regulate the rate of flow of the coating material to the applicator.

While the workpiece feed means is shown as rollers feeding pipe sections through the applicator, it is to be understood that in long sections of pipe or pipe line, as in over-the-ditch coating, the pipe would be elevated sufliciently to permit the applicator to be carried by and used with a movable cart or truck, and the truck or cart may or may not also carry the source of coating material or at least its coupling.

Thixotropic and high solid coating material generally may be any coating that can be applied linearly to the external surface of the pipe and after application thereto will be free from any appreciable drips, runs or sags and the like.

While the applicator means or sleeve is shown as being truncated with an end feed area for admitting the coating material to the applicator, said applicator may be fed through an opening in the top thereof and the large end of the truncated sleeve may be partially at the lower portion thereof to provide a scavenging trough to be flexibly coupled to feed same by a pump back to the applicator.

From the foregoing it will be seen that with the invention there will be a faster application of coatings, and the application does not necessarily depend upon the diameter of the pipe being coated since this is all considered as being an application, normally of a technical material that is supplied with one passage of the applicator over the pipe. The invention will apply coatings which are either thin films or thick layers and with or without solvents being employed.

The present showing is by way of illustration only and is not to be considered as limitations, since many changes and modifications may be made herein without departing from the spirit of the subjoined claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An apparatus for applying a coating to the exterior surface of a tubular workpiece comprising a sleeve memher adapted to be disposed about and in substantial engagement with said tubular workpiece and formed of a flexible, imperforate material; said sleeve member having a cylindrical body portion including the outlet of said member and a conically configured inlet; means swingably mounting said sleeve member at the inlet and thereof whereby said member may adapt itself to non-axially-linear movement of said workpiece; said outlet being formed of an expandable material, a coating material supply associated with the inlet end of said sleeve whereby to apply coating material to said tubular workpiece; an annulus integral with and co-extensive with the outlet end of said member; fluid pressure means in communication with said annulus to effect uniform pressure and spacing of said outlet and with respect to an emergent coated portion of said workpiece whereby a coating of uniform and predetermined thickness may be produced.

2. Apparatus as in claim 1 wherein said fluid pressure means is adjustable.

3. Apparatus as in claim 2 including means, independent of said fluid pressure means, whereby to control the thickness of the applied coating.

4. Apparatus as in claim 3 wherein said means which are independent of said pressure means include means to vary the linear speed of the workpiece being coated.

5. Apparatus as in claim 1 including means to vary the linear speed of a workpiece passing through said sleeve member whereby to control thickness of an applied coating independent of said fluid pressure means.

References Cited UNITED STATES PATENTS OBrien et al. 118-113 Wilson. Seeley 118-125 Perrault 118-404 Stahl 118-405 X Abbott 118-405 Pharris et al. 118-404 Weekley 118-408 X Dayton 25-38 Gardiner et al. 25-38 Wilson 25-38 Robertson 25-38 FOREIGN PATENTS OTHER REFERENCES German printed application 1,105,106, April 1961.

MORRIS KAPLAN, Primary Examiner.

Claims (1)

1. AN APPARATUS FOR APPLYING A COATING TO THE EXTERIOR SURFACE OF A TUBULAR WORKPIECE COMPRISING A SLEEVE MEMBER ADAPTED TO BE DISPOSED ABOUT AND IN SUBSTANTIAL ENGAGEMENT WITH SAID TUBULAR WORKPIECE AND FORMED OF A FLEXIBLE, IMPERFORATE MATERIAL; SAID SLEEVE MEMBER HAVING A CYLINDRICAL BODY PORTION INCLUDING THE OUTLET OF SAID MEMBER AND A CONICALLY CONFIGURED INLET; MEANS SWINGABLY MOUNTING SAID SLEEVE MEMBER AT THE INLET AN THEREOF WHEREBY SAID MEMBER MAY ADAPT ITSELF TO NON-AXIALLY-LINEAR MOVEMENT OF SAID WORKPIECE; SAID OUTLET BEING FORMED OF AN EXPANDABLE MATERIAL, A COATING MATERIAL SUPPLY ASSOCIATED WITH THE INLET END OF SAID SLEEVE WHEREBY TO APPLY COATING MATERIAL TO SAID TUBULAR WORKPIECE; AN ANNULUS INTEGRAL WITH AND CO-EXTENSIVE WITH THE OUTLET END OF SAID MEMBER; FLUID PRESSURE MEANS IN COMMUNICATION WITH SAID ANNULUS TO EFFECT UNIFORM PRESSURE AND SPACING OF SAID OUTLET AND WITH RESPECT TO AN EMERGENT COATED PORTION OF SAID WORKPIECE WHEREBY A COATING OF UNIFORM AND PREDETERMINED THICKNESS MAY BE PRODUCED.

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