US3451434A

US3451434A - Nonuniform wall pipe

Info

Publication number: US3451434A
Application number: US499600A
Authority: US
Inventors: Eugene C Bauer Jr
Original assignee: EUGENE C BAUER JR
Current assignee: EUGENE C BAUER JR
Priority date: 1965-10-21
Filing date: 1965-10-21
Publication date: 1969-06-24
Anticipated expiration: 1986-06-24

Description

June 24, 1969 E. c. BAUER, JR 3,451,434

NONUN IFORM WALL PIPE Filed Oct. 21, 1965 Jwarze/ k @erce C United States Patent 3,451,434 NONUNIFORM WALL PIPE Eugene C. Bauer, Jr., 729 Cumberland Ave., Park Ridge, 1]]. 60068 Filed Oct. 21, 1965, Ser. No. 499,600 Int. Cl. F16] 9/02, 57/00 US. Cl. 138-172 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to pipe having superior service characteristics and more particularly to ferrous pipe having an increased thickness over a portion of the circumference so as to increase its wear resistance.

The generating utility industry has long been faced with the problem of removing highly abrasive material or aggregate such 'as' slag, from coal burners to a refuse area. This slag is the residue or cinders of the unburned coal which is collected from the furnaces, in some instances is, crushed, and is then transported in a water carrier through'pipes formed of numerous pipe sections tothe'refus'e' site. Since the slag is generally in discrete pieces ofa size and specific gravity whereby it is not actually suspended"in' the water carrier, the slag is transported through the pipe so that it is in fairly continuous contact with the bottom segment of the pipe circumference. The characteristics oftheslag particles or pieces are such that the contact .with the lower pipe inner wall tends to wear or erode that portion of the pipe much more rapidly. than therernaining inner wall circumference. Consequently, this segment of the pipe wall wears out long before the other wall segment is worn.

Heretofore, it has been the practice in the industry to estimate or measure the wear in concentric-walled pipe, i.e., a pipe having a constant thickness wall around the entire circumference, and to rotate the pipe during service so as to position the upper Wall segment at the bottom where the greatest wear occurs. It will be readily appreciated that where the pipe length is substantial, for example, several miles in length, this service rotation requires appreciable labor with attendant high costs.

A similar problem exists in other pipe applications where a fluid carrier transports an aggregate. For example, it has been found desirable in some situations to pump concrete through pipe sections wherein the cementitious matrix carries an aggregate of stone. In dredging operations, pipe sections may be used to transport sand and gravel with a water carrier. An air or other gas carrier may also be used in pumping sand through pipe sections within a foundry; or air may be used to carry away the metal chips from machine tool operations.

Accordingly, it is an object of this invention to provide a pipe section having a wall construction wherein the outer wall shape is substantially circular in cross-section and the inner wall shape cross-section is nonuniform or nonsymmetrical so that the lower circumferential portion of the pipe wall is of substantially greater thickness than the remainder of the pipe wall.

It is another object of this invention to provide a pipe section having a nonuniform wall thickness in which the thinnest wall circumferential or arcuate segment is located 3,451,434 Patented June 24, 1969 ice near the top of the pipe section and which gradually and continuously increases in thickness along the circumference to the bottom circumferential or arcuate segment which has the greatest thickness.

It is still another object of the present invention to provide a pipe section of the above-described type wherein the thinnest wall circumferential segment encompasses an approximately arc and the bottom circumferential segment of greatest wall thickness also encompasses an approximately 120 arc.

It is yet another object of the present invention to provide a pipe section of the above-described type wherein the wall thickness is substantially symmetrical about a vertical center line.

For a better understanding of the invention together with other further objects thereof, reference should now be made to the following detailed description which is to be read in conjunction with the accompanying drawing in which:

FIGURE 1 is a perspective view of a pipe section constructed in accordance with the present invention;

FIGURE 2 is a side elevation view of the pipe section shown in FIGURE 1;

FIGURE 3 is a cross-sectional view of the pipe shown in FIGURE 1; and

FIGURE 4 is a side elevation view showing a transition pipe section for connecting a concentric-walled pipe a wall cross-sectional thickness which is nonuniform. Theouter wall shape 26 is substantially circular. The inner wall shape 28 is irregular or nonsymmetrical about a horizontal transverse axis so that the wall 30 thickness varies from the thinnest circumferential wall segment 32 at the top of the pipe section to the thickest wall segment 34 at'the bottom of the pipe. The intermediate segments 36 form a continuous wall surface which joins the seg-'

ments

32, 34 to form a smooth inner pipe section wall free of sharp changes which Would interfere with mixture.

flow. In this regard, it is to be noted that the

segments

32 and 34 are not constant in thickness but vary somewhat so as to provide a continuous curve around the entire nonuniform periphery. The pipe section 20 is preferably formed symmetrically about the vertical center-line 38. It should also be noted that the pipe section is preferably constructed of a ferrous or other substantially wear resistant material.

In FIGURE 4 a transition pipe section 40 is shown for connecting the above described nonuniform thickness wall section 20 to a concentrically-walled section. It Will be seen that the upper wall segment 42 is substantially of uniform thickness while the lower wall segment 44 longitudinally increases in thickness along the pipe section.

The pipe section 20 in FIGURES 1 through 3 is typical of the variation in wall thickness. The thinnest circumferential wall segment 32 is fairly constant in thickness over an arcuate portion of approximately 120. In a pipe section having an outside diameter of 9% inches, for example, this thickness will be approximately /2 inch. The symmetrical intermediate wall segments .36 each encompass an arc of approximately 60 and in a pipe of the aforementioned size the wall thickness varies from /2 inch to nearly 2 inches. The bottom circumferential wall segment 34, having the greatest thickness, is nearly constant at a 2 inch thickness.

' It will be apparent to those skilled in the art that the above-described Segments will not be limited to the arcs stated but may vary depending upon several factors, though the lower wall segments will, of course, always be greater in thickness. The relative wall thicknesses will depend, for example, upon the size of the abrasive pieces which are intended to be transported through the pipe in the fluid carrier. The amount in volume or weight of these pieces relative to the volume or weight of fluid will also be a determinant as well as the velocity and quantity of mixture which is pumped through the pipe. These parameters are not intended to be exclusive or necessarily those of greatest significance in designing the pipe sections in accordance with the present invention but are suggestive of the considerations which are involved in constructing a pipe section having the novel and desirable characteristics now described.

The nonuniform wall pipe section, as previously indicated, is intended for use in transporting a mixture comprising an insoluble aggregate in a fluid carrier. Since the fluid flow will not always carry the aggregate in the true suspended sense, these rough abrasive pieces will be sluiced along the bottom segment of the pipe sections and in frequent contact therewith. The abrasive nature of this aggregate will erode or wear the bottom segment of the pipe sections much more rapidly than that portion of the pipe wall which is contacted only by the fluid. Rather than allow a concentrically-walled pipe to erode irregularly, the variable thickness of the walls of the present invention will result in a wall wearing such that the lower segment will be worn-out at substantially the same time as the upper segment. Thus, no service rotation of the pipe will be required. The material and manufacturing costs of a pipe constructed in accordance with the present invention, however, will be competitive with standard uniform wall thickness pipe sections.

While a preferred embodiment of the present invention has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Accordingly, it is the aim of the appended claims to cover all such changes and modifications as wall within the true spirit and scope of the invention.

I claim:

1. A heavy-duty metal pipe section for transporting a mixture comprising an abrasive aggregate and a fluid, said pipe section having a nonuniform thickness wall with the greatest thickness disposed in position to receive the greatest wear from the mixture passing therethrough, said wall having a substantially circular outer surface and an inner surface which is nonsymmetrical about a transverse horizontal axis and substantially symmetrical about a transverse vertical axis, said wall comprising an upper circumferential segment having the least thickness of the wall, a lower circumferential segment having the greatest thickness of the wall, said upper and lower circumferential segments varying slightly in thickness, and intermediate circumferential segments joining said upper and lower segments, said intermediate segments having a constantly increasing thickness from the juncture with said upper circumferential segment to the juncture with said lower circumferential segment so that a continuous metal Wall is formed.

2. A pipe for transporting a mixture comprising an abrasive aggregate and a fluid in accordance with claim 1 wherein said upper circumferential segment encompasses an arc of approximately and said lower circumferential segment encompasses an arc of no more than 120.

3. A pipe for transporting a mixture comprising an abrasive aggregate and a fluid in accordance with claim 1 additionally including an elongated rib integrally mounted in the center of said upper circumferential segment parallel with the longitudinal axis of said pipe section.

References Cited HOUSTON S. BELL, JR., Primary Examiner.

US. Cl. X.R.