US3006607A

US3006607A - Method and apparatus for introducing lines through conduits

Info

Publication number: US3006607A
Application number: US848119A
Authority: US
Inventors: James C Hamrick
Original assignee: Jet Line Products Inc
Current assignee: Jet Line Products Inc
Priority date: 1959-10-22
Filing date: 1959-10-22
Publication date: 1961-10-31
Anticipated expiration: 1978-10-31
Also published as: DE1150729B; GB885138A; FR1268872A

Description

Oct. 31, 1961 J HAMRlcK 3,006,607

METHOD AND APPARATUS FOR INTRODUCING LINES THROUGH CONDUITS Filed Oct. 22, 1959 C Q H \O INVENTOR JAMEs C. HAMEJCK ATTORNEYS United States Patent 3,006,607 METHOD AND APPARATUS FOR INTRODUCING LKNES THROUGH CONDUITS James C. Hamrick, Charlotte, N.C., assignor to Jet Line Products, Inc, Charlotte, N.C., a corporation of North Carolina Filed Oct. 22, 1959, Ser. No. 848,119 7 Claims. (Cl. 254-1344) This invention relates to a method and apparatus for introducing a guide line through a conduit, the guide line thereafter being connected to a relatively rigid line or similar elongated article-such as an electrical cable or conductor, a lengthy thermosensitive element, etc.- for drawing the relatively rigid line or similar elongated article within the conduit by pulling on the guide line.

Previous attempts to pass a guide line through a conduit have included the use of fluid pressure to force a projectile through the conduit, the projectile having one end of the guide line attached to its trailing end and the fluid pressure being continuously applied against the rear end of the projectile to thrust it forwardly. The frictional resistance encountered between the projectile, its attached line and the conduit increases markedly as the projectile is thrust through the conduit because of the increasing frictional drag of the line as more of it is pulled into the conduit. The projectile itself is relatively heavy, thereby presenting considerable weight which must be overcome by the fluid pressure before forward movement of the projectile is effected.

It has also been proposed to introduce a guide line through a conduit by providing a projectile which is adapted to form a seal with the internal wall surface of the conduit, wherein a reel of line is housed within the projectile with its longitudinal axis transversely disposed to the longitudinal extent of the projectile and the conduit. Fluid pressure is then continuously applied against the rear end of the projectile to push it forwardly. As the projectile moves forwardly, the line from the reel is payed out in the conduit. This practice is relatively slow and ineficient because the conduit rnust be leak-proof and of substantially uniform diameter throughout its length. The projectile must be of a particular size \m'th respect to the conduit through which it is to be passed to insure a good seal therebetween. Moreover, the frictional resistance created by such a device requires a substantially unlimited source of fluid pressure to enable the projectile to pass completely through the conduit.

in co-pending United States patent application Serial Number 674,930 filed July 29, 1957, now US. Patent 2,930,584 issued March 29, 1960, there is disclosed a self-propelled cartridge projectile which is utilized in introducing an attached guide line through a conduit. While the method and apparatus disclosed in the aforesaid application are eminently satisfactory for introducing a guide line through a conduit, diificulties are encountered Where the conduit possesses a relatively small internal diameter of the order of /2 or Under such conditions, the compulsory size limitations placed on the cartridge projectile to enable it to pass freely within the conduit unduly restrict the quantity of gaseous pressure it may hold and which serves as its propellant. Accordingly, all of the gaseous pressure may be dissipated from the cartridge projectile before it has completed its journey through the conduit.

In all of the above-noted approaches, some form of rigid, relatively heavy projectile is employed as a carrier to introduce the guide line through a conduit. A conduit having one or more angular bends therein creates special problems which, although overcome to some extent, restrict the instances where such approaches may be successfully employed. In many cases, a sharp angular bend in a conduit will prevent conventional procedures for introducing a guide line through the conduit from accomplishing the desired results. The sharp angular bend may cause the line-carrying projectile to become wedged in the conduit whereupon measures must be taken to extricate the projectile from the conduit resulting in prolonged delays before the introduction of the guide line through the conduit may be accomplished.

It is an object of the present invention to provide an improved method of introducing a guide line through a conduit by utilizing a package containing a supply of line which has an outer diameter smaller than the internal diameter of the conduit and which may be blown through the conduit by fluid pressure, to cause the line to be payed off from the package and laid in the conduit as the package moves therethrough. The improved method contemplates the application of a jet of fluid pressure of a relatively high magnitude against the package to thrust the package rapidly forward, the package thereafter passing through the conduit on its forward momentum built up by the jet of fluid pressure. In addition, a continuous application of fluid pressure at a lower magnitude against the package could be employed to blow the package through the conduit.

It is another object of this invention to provide a method of introducing a guide line through a conduit having one or more angular bends therein by utilizing a flexible package containing a supply of line which has an outer diameter smaller than the internal diameter of the conduit, directing fluid pressure against the package to propel it through the conduit, and flexing the package to substantially conform to each angular bend in the conduit as it passes therethrough, while paying out line from the package as it moves through the conduit.

It is another object of this invention to provide apparatus for introducing a guide line through a conduit wherein the apparatus comprises a lightweight line package having a smaller outer diameter than the internal diameter of the conduit, a source of fluid pressure, and means for directing the fluid pressure against the rear end of the line package for freely thrusting it through the conduit, the line being payed out from the package as it moves through the conduit.

Another object of the present invention is to provide a method and apparatus for introducing a guide line through a conduit which completely eliminates the possibility that the conduit may become permanently blocked by the instrumentality employed as the line carrier. One impressive advantage of the flexible lightweight line package as employed in the present instance over conventional procedures resides in the fact that permanent blockage of the conduit, where a line carrier has become wedged in a constricted portion of the conduit and all etforts to dislodge it have failed, cannot occur. Should the line package become temporarily wedged in the conduit, more line may be removed from the package by pulling on the end extending from the conduit until the wedged condition is relieved.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIGURE 1 is a schematic view showing a conduit extending through a building, wherein a line package is being passed through the conduit in accordance with the present invention;

FIGURE 2 is a greatly enlarged fragmentary longitudinal sectional view of the line package traveling through the conduit, taken along line 22 in FIGURE 1; and

FIGURE 3 is a greatly enlarged sectional view of a conduit having an angular bend therein, the line package being shown in elevation as it passes through the bend.

Referring more specifically to the drawings, FIGURE 1 schematically illustrates the present method and apparatus for introducing a guide line through a conduit. Thus, in FIGURE 1 a conduit C extends throughout a building, the conduit C having angular bends therein at various locations along its extent and being interrupted at one or more places for receiving junction boxes I.

In practicing the improved method, a line package is employed as the medium for introducinga guide line through the conduit. The line package comprises a casing or wrapping 11 of suitable material, such as paper or plastic, the casing 11 having an elongated substantially cylindrical shape. A supply of pliable line L is wound in an elongated cylindrical roll 12 which fits snugly within the casing 11. The cylindrical roll 12 of line L is preferably wound so that the line L may be unwound from its center outwardly. In this manner, the outer diameter of the line package 10 and substantial frictional engagement between the cylindrical roll 12 and the casing 11 are maintained as the line L is dispensed from the line package 10 as subsequently described.

The line package 10 is flexible in nature, such flexibility being enhanced by means in the form of one or more score lines 13 provided in the casing 11 medially of its ends and eachsuch score line 13 serving as a weakened portion on the casing 11. A suitable source of fluid pressure which may be in the form of a portable container 14 of compressed gas preferably having a magnitude of 300 pounds per square inch (as shown in FIGURE 1) communicates with one end of the conduit C by means of flexible tubing 15. The supply of fluid pressure to one end of the conduit C is controlled by suitable means, such as a manually operable valve 16.

In practicing the method, one end of the line L is withdrawn from the cylindrical roll 12 and secured to a point located outside of the conduit C. The line package 10 is then inserted in one end of the conduit C and the flexible tubing 15 is positioned with its outlet end disposed in the .conduit C behind the rear end of the line package 10.

Upon opening the valve 16, the line package 10 is subjected to a jet of fluid pressure from the portable container 14. It will be observed that a major portion of the fluid pressure impinges upon the rear end of the line package 10, while a proportionally smaller amount is permitted to pass beyond the line package 10 in the space between the conduit C and the line package 10. The lightweight line package 10 is immediately thrust forward in the conduit C by the impact of the fluid pressure against its rear end. In this connection, it will be noted that the line package 10 although having an outer diameter which is smaller than the internal diameter of the conduit C, possesses a cross-sectional area which substantially fills the conduit C. The initial forward thrust imparted to the line package 10 by the fluid pressure builds up forward momentum enabling the line package 10 to travel through the conduit C and out of its opposite end. As the line package 10 moves through the conduit, the line L is unwound from the cylindrical roll 12 and payed out in the conduit C. Since the line L is unwound from the center of the cylindrical roll 12 outwardly, the outer diameter of the cylindrical roll 12 is unchanged, thereby maintaining the same cross-sectional dimensions for the line package 10 as it travels through the conduit C.

Although the line package 10 possesses considerable flexibility, this flexibility is enhanced by the one or more score lines 13 located along its longitudinal extent. Preferably, the outer casing or wrapping 11 of the line package 10 is broken along each score line 13 before the line package 10 is inserted within the conduit C to increase the flexibility of the line package 10, thereby enabling it to better negotiate sharp angular bends in the conduit C, as illustrated in FIGURE 3. The line package 10, upon encountering an angular bend in the conduit C, flexes to conform with the bend as it passes therethrough.

In the installation of the conduit C during construction work, it is likely that one or more crimped places K (FIGURE 3) will be formed thereon by the striking of a rigid object, such as a tool, against the conduit C. The crimp K creates a reduced internal diameter portion for the conduit C where it is located and may seriously impede or actually stop a conventional rigid line-carrying projectile from completing its journey through the conduit C. In the present instance, the highly flexible line package 10 may conform to the crimp .K for passing through the reduced internal diameter portion of the conduit C caused thereby. There may be occasions when the crimp K is extremely severe. Under such conditions, a rigid projectile is apt to become hopelessly wedged in the conduit C. On the other hand, the line package 10 while it may be temporarily lodged in the conduit C because of the impediment created by the crimp K, can always be dislodged or removed. To dislodge the line package 10, an operator may pull on the line L extending from the end of the conduit C through which the line package 10 entered to remove additional line from the cylindrical roll 12. The operator continues to remove line from the cylindrical roll 12 in this manner until the line package 19 can be blown past the impediment by a jet of fluid pressuref Under the Worst possible constricted condition in the conduit C, it may be necessary to withdraw all of the line L from the line package 10 in the manner indicated to remove the line package It from the conduit C. Regardless of the nature of angular bends and crimps K in the conduit C, the line package 10 used in the present method cannot became permanently lodged therein.

It has been determined that a source of fluid pressure having a relatively high magnitude is capable of thrusting the line package 10 through a relatively long conduit C by directing a jet of such pressure against the rear end of the line package 10, rather than directing a continuous stream of fluid pressure thereagainst. The momentum initially built up in the line package 10 by the sudden impact of the jet of fluid pressure is normally suflicient to thrust the line package 1!) completely through the conduit C. Of course, the present invention also contemplates the use of a fluid pressure source having a somewhat lesser magnitude in which fluid pressure is continuously applied against the rear end of the line package 10 until it has completed its journey through the conduit C. The lightweight line package 10 is propelled through the conduit C at a high rate of speed, enabling it to jump across interruptions in the conduit C created by junction boxes I.

In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim:

1. The method of introducing a pliable line through a conduit having at least one angular bend therein comprisrng the steps of directing fluid pressure against a flexible line package having an outer diameter less than the internal diameter of the conduit, blowing the line package freely through the conduit by the fluid pressure, guiding the line package past all angular bends in the conduit by flexing the line package to substantially conform to the shape of each such angular bend as it moves therethrough, and paying out line from the line package in response to the movement of the line package through the conduit.

2. The method of introducing a pliable line through a conduit having at least one angular bend therein comprising the steps of directing a jet of fluid pressure against the rear end of a flexible line package having an outer diameter less than the internal diameter of the conduit to induce rapid forward movement of therline package, passing the line package through the conduit by the forward momentum built up by the jet of fluid pressure, guiding the line package past all angular bends in the conduit by flexing the line package to substantially conform to the shape of each such angular bend at is moves therethrough, and paying out line from the line package in response to the movement of the line package through the conduit.

3. The method of passing a flexible line carrier through a conduit having at least one angular bend therein, wherein the line carrier has an outer diameter less than the internal diameter of the conduit, comprising the steps of directing fluid pressure against the line carrier, blowing the line carrier freely through the conduit by the fluid pressure and guiding the line carrier past all angular bends in the conduit by flexing the line carrier to substantially conform to the shape of each such angular bend as it moves therethrough.

4. Apparatus for introducing a line through a conduit comprising an elongated line package having a casing with an outer diameter less than the internal diameter of the conduit and a supply of line wound in a cylindrical roll fitting snugly within said casings, said casing and said cylindrical roll of line being flexible throughout their longitudinal extents, a source of fluid pressure, means for directing fluid pressure from said source against said package to propel said package through the conduit, and said line being unwound from the cylindrical roll and payed out in the conduit in response to the movement of said package through the conduit.

5. Apparatus for introducing a line through a conduit comprising an elongated cylindrical line package having a cylindrical casing with an outer diameter less than the internal diameter of the conduit and a supply of line wound in a cylindrical roll fitting snugly Within said cylindrical casing, said cylindrical casing and said cylindrical roll of line being flexible throughout their longitudinal extents to provide flexibility for said line package along its entire length, a source of fluid pressure, means for directing fluid pressure from said source against said package to propel said package through the conduit, said line being unwound from the cylindrical roll and payed out in the conduit in response to the movement of said package through the conduit, and said package flexing at any point along its length to conform to irregularities in the conduit for moving therethrough,

6. Apparatus for introducing a line through a conduit comprising an elongated cylindrical line package having an outer diameter less than the internal diameter of the conduit and a supply of line wound in a cylindrical roll fitting snugly therewithin, means on said package providing a weakened portion medially of its ends, a source of fluid pressure, means for directing fluid pressure from said source against said package to propel said package through the conduit, said line being unwound from the cylindrical roll and payed out in the conduit in response to the movement of said package through the conduit and said package bending in the area of said means providing the weakened portion thereon for passing through an angular bend in the conduit.

7. Apparatus for introducing a line through a conduit comprising a supply of line wound in an elongated roll having an outer diameter less than the internal diameter of the conduit, said elongated roll being flexible throughout its longitudinal extent, a source of fluid pressure, means for directing fluid pressure from said source against said elongated roll to propel said elongated roll through the conduit, and said line being unwound from said elongated roll and payed out in the conduit in response to the movement of said elongated roll through the conduit.

References Cited in the tile of this patent UNITED STATES PATENTS 252,956 Loane Ian. 31, 1882 395,881 Cunningham Jan. 8, 1889 1,072,969 McCreary Sept. 9, 1913 2,470,338 Chilton May 17, 1949 2,822,146 Ridgers et a1. Feb. 4, 1958