US1984125A - Method of making culverts - Google Patents

Description

1934- J. R. FREEZE ETAL 8 METHOD OF MAKING CULVERTS Original Filed Oct. '7, 1931 INVENTORS,

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ATTORNEYS,

Patented Dec. 11, 1934 UNITED STATES PATENT OFFICE i, METHOD OF MAKING CULVISE'IS application October 7, 1931, Serial No.

567,461. Divided and this application June 2, 1933, Serial No. 674,057

'lClaims.

This application is a division of application Serial No. 567,461 filed October 7, 1931.

Our invention relates to the manufacture of corrugated metal culverts having erosion and corrosion resisting linings, and to methods of making the same.

Corrugatedsteel or iron culverts (usually galevanized) are of great value in the arts because of their great strength and relatively light weight and small bulk as compared to brick, concrete or tile culverts. When subjected to excessive loads, corrugated metal culverts will distortin shape to conform best to load conditions. This is not possible with concrete or tile culverts,

-.and is no doubt one of the reasons which enable the use of a corrugated metal for culvert purposes. g

The zone of weakness in a metal corrugated culvert is in the invert or lower section of the culvert, particularly along what may be termed the base thereof. Gravity fiow of water and whatever soil, dirt or abrasive matter it carries, is along the base of a culvert.

In U. 8. Patent No. 1,652,703, dated December 13, 1927,.to Allerton S. Cushman, is shown and described a culvert having a paving oi asphaltic material in the basethereof, which forms a level floor along the base of the culvert and protects the sides ordinarily by a fairly thin film of the bitumen. According to the Cushman patent, asphalt while fluid is placed into a culvert section which is then held level while the asphalt hardens. The asphalt flows to the center of the base line of the culvert and fills the corrugations, forming a pool along the center line. This, when hard, forms a level floor in the culvert. The culvert iseither dipped into molten bitumen or sprayed internally with it, in the process of manufacture, as a mode of placing the bitumen in the culvert. Where it is desired to have the corrugations filled, toan extent greater than a single collected pool inv the base of the culvert will do, there will'haIve to be subsequent dippings or sprayings with the culvert tilted slightly at an angle to its position during the first dipping or spraying. y a

This re-dippins or spraying and subsequent hardening is a somewhat cumbersome method of procedure. Also, where a series oi clippings are made, the more extended corrugationfilling or fioor in the culvert is not smooth and round, but has one or more angles where the several coatings or fillings join.

It is an object oi our invention to provide for a way oi filling the corrugations of a corrugated culvert to whatever depth and to whatever width of sector of the culvert is desired, by a simpler method of application and with enhanced results.

Thus it is our object to make the filling separate.from the culvert and arrange to have it inserted and bound in place later. This has an advantage in practice, since it avoids the necessity of a series of treatments by filling, heating and cooling, and requires simpler equipment at the culvert factory.

We have illustrated in the drawing an example of our invention, and will describe the same in full. In the claims that follow, we setiorth the essentials making up our invention, and we here refer to the claims without further discussion oi possible variations or modifications of our invention.

In the drawing:'

Figure 1 is .a perspective view oi a piece oi molded culvert filling, showing its shape before it is placed into the culvert.

Figure 2 is a perspective, partly broken away,

metal culvert at 1. At 2 is illustrated a typical filling for the culvert. This is a molded product having a top surface which is smooth and cylindrical, and a bottom surface 3 which is corrugated exactly to correspond to the interior corrugations of a culvert into which it is to be placed. The lateral margins 4 may be tapered so as to avoid any abrupt shoulder when the lining is inserted in the culvert. The ends oi the sections may be made smooth, to make butt joints with the fillings of adjoining sections, or may be made specially to establish a different style of joint. As a material for the lining we use preferably a fiber reinforced bituminous compound, which, when cold, is flexible and limp, and will have a shape such as shown in Fig. 1, before it is placed into the culvert.

In the simplest practice the metal sections are made up at the culvert factory, and the filling made up at a factory where there is proper equipment for making molding compounds and molding them. When theculverts are to be lined or filled, the lining is inserted in place, the culvert section heated externally so as to soften the 'contacting surface of the lining, and the outside of the culvert then cooled or permitted to cool. The result of the heating will be tobond the lining to the culvert, which will be permanent except for a reheating.

We have also found in actual practice if we place ordinary burlap between the interior floor of the culvert and the asphalt lining, a better bond between the culvert section and insert filling is provided, particularly in cold temperatures, and in addition if the culvert section is subjected to rough usage before or during installation, the asphalt cake will remain intact and firmly bonded to the culvert. Again, if this burlap layer is attached to the asphalt lining at the factory and the unit is roughly handled while being shipped or transported to the place of use, the asphalt cake will remain as a unit and will not be broken or rendered unfit for use.

The degree of curve in cross section of the lining pieces can be as desired. If the entire interior of the culvert is to be lined, there will preferably be two half cylinders or multiple sections of the lining used, depending on the diameter of the culvert.

A simple factory equipment can be used, such as a conveyor, a material holder to use in inserting the lining and dropping it into place with the corrugations thereon meshing with those in the culvert, and a heater over which the conveyor carries the culvert section with lining in place, and finally, a water spray for chilling the outside of the culvert to prevent dislodgment or slipping of the lining and to save time in holding the completed article until cooled down in the atmosphere.

Any convenient mode, however, of heating up the culvert section after the lining is in place will serve.

The thickness of the filling can be controlled as desired, and tapered 01'1" to the sides away from the center with consequent saving of material where easy conditions of use are to be met.

With a molded top surface, it is evident that the exact type of surface, level, curve, etc., that is desired can be provided.

Our invention should be distinguished from instances where it has been suggested to mold within a pipe section some filling material, or to insert within the invert of a pipe section, some level fiow sustaining fioor, which is of metal, ceramic material, or otherwise formed.

As material for the filling pieces, the chief requisites are that they be heat plastic, of high adhesiveness. and flexible at room temperature so that it will adapt itself to any particular shape of culvert to be lined. The bituminous ingredient should not be short or brittle in nature, so as to allow for contraction and expansion, and also for distortion under load of the culvert in which it is placed.

In order to insure against trapping of air between the lining and the inner culvert wall, it is advisable to rock the culvert in a direction circumferential of the culvert section, or to shake or jar the culvert when his being heated for bonding the lining in place. It is advantageous to heat the culvert first on its lowestpart, thus allowing any entrapped air to escape up the sides before the bonding takes place. It furthermore is helpful in avoiding entrapment of air if the corrugae tions of the lining are made somewhat higher than would correspond to the corrugations of the metal culvert.

In spite of the cost of molding, the lining of culverts as we have described, is more economical than the former methods employed, as well as the product being one of enhanced value and greater accuracy. The only heating of the filling material sufiicient to melt it is done prior to molding. The heating of the culvert section is brief, and purposely kept down to just sufiicient to establish a bond with the lining. There is no necessity for re-dipping for a second filling.

While our culverts may be dipped after the lining is in place, this is not necessary. In case dipping. is done, however, the molded linings will preserve their form better than the linings as provided for in the process described in said Cushman patent.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent, is:

1. A method of filling the corrugations of a corrugated sheet metal culvert, which consists in forming the culvert section, molding a heatplastic filling therefor having on its one face corrugations to match the corrugations of the culvert section, placing the filling section in the culvert in meshing position as to corrugations. and applying heat to the outside of the culvert sufiicient to melt the contacting surface of the filling, wherefore it will bond with the culvert interior.

2. A method of filling the corrugations of a corrugated sheet metal culvert, which consists in forming the culvert section, molding a heat- 5 plastic filling therefor having on its one face corrugations to match the corrugations of the culvert section, placing the filling section in the culvert in meshing position as to corrugations, and applying heat to the outside of the culvert sufiicient to melt the contacting surface of the filling, wherefore it will bond with the culvert interior, and subsequently cooling the culvert section, as by a suitable spray.

3.A method of filling the corrugations of a 1 corrugated sheet metal culvert, which consists in forming. the culvert section, molding a heatplastic filling therefor having on its one face corrugations to match the corrugations of the culvert section, placing the filling section in the culvert in meshing position as to corrugations, and applying heat to the outside of the culvert sufiicient to melt the contacting surface of the filling, wherefore it will bond with the culvert interior, and jarring the culvert section during interior, and producing a reciprocating movement in a circumferential direction of the cul vert section during the heating, for the purpose described.

5. A method of filling the corrugations of a corrugated sheet metal culvert, which consists in forming the culvert section, molding a heatplastic filling therefor having. on its one face corrugations to match the corrugations oi the culvert section, attaching burlap to said filling, placing the filling section in the culvert in mesh= ing position as to corrugations, and applying heat to the outside of the culvert sumcient to melt the contacting surface of the filling, wherefore it will bond with the culvert interior.

6. A method of filling the of-a corrugated sheet metal culvert, which consists in forming the culvert section, placing burlap on the interior fioor thereof, molding a heat-plastic 75 the culvert section, separately molding a heat filling therefor having on its one face corrugations to match the corrugations of the culvert section, placing the filling section in the culvert in meshing position as to corrugations, and applying heat to the outside of the culvert sufficient to melt the contacting surface of the filling, wherefore it will bond with the culvert interior.

7. A method of producing a paved corrugated sheet metal culvert, which consists informing plastic filling therefor having on one of its faces corrugations substantially corresponding to the corrugations of the culvert section, placing the filling in the culvert section in meshing position as to corrugations, and bonding the filling to the culvert section.

JONATHAN ROY FREEZE. RALPH W. SHAR'ILE.

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