US3530822A

US3530822A - Apparatus for coating the interior of pipes

Info

Publication number: US3530822A
Application number: US507990A
Authority: US
Inventors: Gerardo Di Mura
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-11-23
Filing date: 1965-11-23
Publication date: 1970-09-29
Anticipated expiration: 1987-09-29

Description

United States Patent Continuatidn in-part 0f Ser. No. 463,600, June 14, 1965, abandoned [45] Patented Sept. 29, 1970 [S4] APPARATUS FOR COATING THE INTERIOR OF 1,909,733 5/1933 Thwaits l37/267X 2,091,544 8/1937 Hitz ll8/306X 2,167,268 7/1939 Sanger 242/54X 2,664,911 l/l954 Thompson et a]. l37/574X 2,758,917 8/1956 Popp 1l8/306X 2,819,188 l/l958 Metheny et al. ll8/6l2X 3,022,765 2/1962 Xenis 118/2 3,222,704 12/1965 Ciaccio 15/1043 Primary Examiner.lohn P. McIntosh ArrorneyFrederick W. Padden ABSTRACT: Apparatus is disclosed for spraying in a single operation the interior of a relatively long section of a gas main with a sealing compound by connecting a relatively light, flexible snake line to a nozzle attached to a hose at a first one of the two extremities of the gas main section and drawing the snake line from an opening at the first gas main extremity through the interior of the main to an opening in the gas main at the second extremity while the sealing compound is pumped through the hose and is sprayed out of the nozzle in a plurality of discrete angles into contact with the interior of the gas main. Reel means, multiorifice-angled nozzle and plural gas main saddle arrangements are disclosed for facilitating the spraying operation.

Patented Sept. 29, 1970 Sheet INVENTOR. GERARDO DIMURA A T TOR/V5) Patented Sept. 29, 1970 Sheet 2 of 8 INVENTOR. GERARDO D/MURA A T TORNE V Patentd Sept. 29, 1970 3,530,822

Sheet 3 018 TRANSPARENT n nvoow 2/3 I T I ACCESSORY HOLDER LOCK 32 s/vmr POR r HOLE RUBBER GAS/(5T PIPE 3/ F M Q7 \\I\J\V/ 700045 ASSEMBLY 30 P/PE a;

ACCESSORY HOLDER L OCK INVENTOR.

GERARDO D/MURA A r TOR-IVE) Patented Sept. 29, 1 970 3,530,822

Sheet i of 8 FIG. 4B

GASKET I 1 W11 H 4/ INVENTOR.

GER/I R00 D/MURA e A TTOR/VEV Patented Sept. 29, 1970 Shet M QM mm o I R Patented Sept. 29, 1970 Sheet 9 mituwt. 0236mm INVENTOR. GERARDO DIMURA ATTORNEY Patented Sept. 29,

7 bra Sheet MbbvG NEE whom Gm Hukk IN VEN TOR GERA R00 D/MURA 9 ATTORNEY Patented Sept. 29,1970

POWER SOURCE TANK 70/ PULLEV PULLEY CHAMBER A H\ BAFFLE PLATE 804 CHAMBER B FIG 8B PULLEV aoa PULLE) 803-2 SHAFT SHAFT 805-! 805-2 IMPELL ERS & IMPELL [R5 806-! 806-2 REsEm O/R T TANK 70/ BAFF'LE PLATE e04 INVENTOR GE RA R00 DIMURA ATTORNEY APPARATUS FOR COATING THE INTERIOR OF PIPES This application is a continuation-in-part of Ser. No. 463,600 filed June 14, 1965, now abandoned.

This invention relates to the sealing of pipe joints in a piping system, and in particular to the sealing of a large number of joints in a single operation.

lt is well known that the conversion from so-called manufactured" gas to natural gas by many public utilities has been accompanied by serious leakage problems in gas piping systems because of the dehydrating action of natural gas on the packing or caulking in the joints between adjacent, contiguous sections of pipe. A number of arrangements have been proposed to solve this problem, one of the best known being the method of spraying the internal surface of a piping system with a sealing compound, as described in G. E. Hitz Pat. No. 2,091,544, issued Aug. 31, 1937, and C. P. Xenis Pat. No. 3,022,765, issued Feb. 27, 1962.

ln a typical arrangement for spray coating the interior of a selected length of underground gas main, the opposite extremities of the selected length are exposed by excavations, and a hole is drilledin the main at each exposed extremity. A gland is positioned over each hole to prevent the leakage of gas during the coating operation so that gas service is not interrupted, and a snake line is passed through the gland at one extremity of the pipe and urged through the pipe to the,other extremity. When the snake line reaches the opposite extremity, a nozzle and hose are secured to the end of the snake line, after which the snake line is withdrawn toward its original point of entry, carrying with it the nozzle and hose. While the snake line is being withdrawn, a sealing compound is forced through the hose and nozzle under pressure to coat the interior of the main. When the hose has been drawn through the entire selected length of gas main, the snake line and hose are disconnected, and the hose is then pulled out of the gas main back to its original point of entry. If desired, the spraying operation may be repeated while the hose is being withdrawn.

Because of equipment limitations, the sealing of pipe joints by the spray coating method has been an expensive, time-consuming operation. For example, with available snake line equipment, a typical length of gas main to be sprayed at one time has been limited to approximately 300 feet and has required four or more operators. Therefore, the excavations must be made at approximately 300-foot intervals, and all of the snake line and spraying equipment must be disconnected and moved to the next pair of excavations after spray coating each SOD-foot section of gas main. As a result of the substantial amount of time and labor required to make numerous excavations and to move and adjust the spray coating equipment, public utilities have incurred large expenses in order to prevent gas leakage.

In order to reduce the time and expense required by the conventional spray coating technique, it is an object of the present invention to provide an improved spray coating arrangement by means of which the interior of gas main sections as long as 500 to 900 feet may be spray coated in a single operation by only two men. By spray coating relatively long sections of gas main in a single operation, significant economies are realized, both by reducing the number of excavations, and by reducing the amount of time spent in disconnecting and moving the snake line and spraying equipment from one pair of excavations to the next.

One of the features of this invention by which a relatively long section of gas main is spray coated in a single operation is a relatively light, flexible snake line which easily passes over obstructions and around curved portions of the gas main without imposing undue strain on the power source that controls the movement of the snake line. However, it was found that with conventional reels onto which snake lines of common large sizes are ordinarily rewound automatically without difficulty, the snake line employed in practicing this invention is too light and flexible to be rewound automatically. Since automatic rewinding is necessary in order to conserve time, the present invention provides a so-called reel guide, which, when incorporated in a conventional reel, guides the snake line onto the reel so that the rewinding is performed automatically.

Since it is desirable to maintain an uninterrupted flow of gas during the entire spray coating operation, the arrangement provided by the present invention also prevents the leakage of gas in a manner that permits rapid performance of the spray coating operation. This is accomplished by covering the opening in the pipe at each extremity with a unique set of pipe saddles during the spray coating operation. Each pipe saddle is 0 provided with a mechanism that permits the saddle to be quickly connected or disconnected to the gas main, and each saddle is also provided with an entry port adapted to permit either the snake line or the hose to pass through the port without loss of gas. Further, in order to minimize the time required to connect the hose to the snake line, the opening in the gas main at which the hose is to be inserted is provided with a saddle having a transparent, gas-tight window. This window permits a workman at the extremity of the gas main section toward which the snake line is being urged to detect immediately the arrival of the snake line, so that the operator of the snake line equipment may be signaled to stop the snake line in order to permit rapid connection of the nozzle and hose to the snake line. In this manner, the present invention avoids wasted motion and lost time in connecting the snake line and nozzle.

Because relatively long sections of pipe can be spray coated by the arrangement provided by this invention, it is important that the sealing compound be applied uniformly and consistently to the entire interior of the gas main in order to avoid the expense of repeating the coating operation. To accomplish this, the present arrangement includes a nozzle through which the sealing compound is simultaneously sprayed in several different directions while the hose is drawn through the gas main. Specifically, the nozzle is provided with at least three sets of spray orifices: a first set for directing the coating material to meet the interior of the gas main at an acute angle and in advance of the direction in which the nozzle is being drawn; a second set for directing the coating material to meet the interior of the gas main at a right angle and perpendicular to the direction in which the nozzle is being drawn; and a third set for directing the coating material to meet the interior of the gas main at an acute angle and in a direction opposite to that in which the nozzle is being drawn. Since the caulking between joints may be facing in various directions because of factors such as curvature of the main, variations in design, and the like, the provision of various spraying angles ensures that the joints will be thoroughly coated in a single operation regardless of the various directions in which the caulkings face.

An additional feature of this system is the maintenance of the sealing compound in a homogeneous condition at all times. This is accomplished by storing the sealing compound in a tank whose interior is divided into chambers separated from one another by baffle plates which allow sealing compound to pass between chambers but prevents surging and foaming of the compound. Within each chamber there is provided an agitator mechanism that is kept in continuous motion, thereby continuously mixing the sealing compound and maintaining a homogeneous solution.

The invention will be fully understood from the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic drawing illustrating a longitudinal view of a selected section of an underground gas main, partly in section, together with apparatus embodying the novel principles of this invention;

FIG. 2 is a front elevation view of the pipe saddles of this invention;

FlG. 3A is a side elevation, partially in section, of a pipe saddle fitted with a detachable transparent window;

FIG. 3B is a plan view, partially in section, of a pipe saddle of this invention;

FIGS. 4A and 4B respectively illustrate a plan view and a side elevation view, partially in section, of a gasket holder adapted to be fitted to the pipe saddle of this invention;

FIGS. 5A and 5B are respective plan and side elevations, partially in section, of the spray nozzle of this invention;

FIG. 6 is a perspective view of a reel for automatically rewinding a light, flexible snake line of the type employed in this invention;

FIG. 7 is a schematic diagram of pumping equipment em ployed in the apparatus shown in FIG. 1; and

FIGS. 8A and 8B are plan and elevation views, respectively, of the agitator mechanism for continuously mixing sealing compound.

Turning first to FIG. 1, excavations 16-1 and 16-2 are made to expose the extremities of a relatively long section of buried gas main 17; for example, this invention is designed to spray coat in a single operation of section on the order of 500 to 900 feet in length, although shorter lengths may also be spray coated if desired. Gas main 17 is characterized by a number of joints 18 that are to be coated by the apparatus of this invention in order to prevent and close leaks in the caulking of these joints. A hole is drilled into the gas main at each exposed extremity, and saddles 14 and 15 are secured to the gas main over each hole to prevent the leakage of gas from these holes so that uninterrupted gas service may be supplied to customers during the spray coating operation. Adjacent to one excavation, say excavation 16-1, a so-called rodding machine 10 is positioned, where the rodding machine contains a reel 100 on which there is wound or coiled a relatively light, flexible snake line 101 or rod. For example, snake line 101 may be a A" steel wire, and reel 100, as explained below in connection with the detailed description of FIG. 6, is especially adapted to rewind this kind of light, flexible snake line automatically.

Snake line 101 is unwound from reel 100 by means of a suitable power source, not shown in the drawing, which may be a conventional gasoline engine contained within rodding machine 10. As snake line 101 is unwound from reel 100, snake line 101 is led out of rodding machine 10 and into gas main 17 through saddle 14. As described below, saddle 14 is provided with an entry port having an appropriate gland that prevents leakage of gas but permits passage of snake line 101 in either direction through gas main 17. The light weight and flexibility of snake line 101 permit it to pass easily over obstructions and through bends in the gas main section, so that the snake line may be urged relatively quickly to the opposite extremity exposed at excavation 16-2.

A transparent section or window in saddle 15 at the opposite extremity of the gas main section exposed at excavation l62 enables an operator at excavation l62 to detect immediately the arrival of the snake line and to signal the operator at the rodding machine to stop unwinding the snake line. Signaling may be accomplished by conventional radio equipment. The transparent window is then removed and replaced by a suitable gland designed to allow the passage of hose 12 in either direction through gas main 17. After making the connection between snake line 101 and nozzle 13, the operator at excavation l62 signals the operator at excavation 16-1 to start the power source to rewind snake line 101 automatically onto reel 100 in order to draw nozzle 13 and hose 12 through the gas main. When the rewinding of snake line 101 starts, the operator at excavation l62 simultaneously starts unreeling hose 12 carried by truck 11 on a suitable hose reel shown in FIG. 7, and turns on the pumping equipment also carried on truck 11 and shown in FIG. 7 so that the sealing compound stored in truck 11 is sprayed on the interior surfaces of gas main 17 to coat the packing of joints 18. After nozzle 13 reaches saddle 14 at excavation 16-1, rodding machine 10 and the pumping equipment on truck 11 are turned off, snake line 101 is disconnected from nozzle 13, and the operator at excavation 16-2 reels in the hose and nozzle. If desired, during the reeling in of the hose and nozzle the pumping equipment may be turned on in order to repeat the spraying operation. Rodding machine 10 and truck 11 are then moved to the next pair of excavations to repeat the entire spray coating operation.

Referring next to FIGS. 2, 3A, 33, 4A, and 48, these drawings illustrate the features of the saddles of this invention. As shown in FIG. 3A, a saddle is secured to a pipe 31 by releasing a suitable toggle assembly 30 so that the saddle may be positioned around the pipe with the entry port of the saddle centered over the hole in the pipe, after which the saddle is secured in place by moving toggle assembly 30 to its locked position.

As shown in FIG. 2, at the excavation where the snake line is introduced into the gas main, for example, excavation 161 in FIG. 1, saddle 20 is provided with a gland 201; for example, a flexible gasket pierced in the center to permit passage of the snake line while preventing the leakage of gas. At the excavation where the hose and nozzle are introduced into the gas main, for example, excavation 16-2 in FIG. 1, saddle 21 is provided with an accessory holder lock 32 illustrated in FIG. 3A comprising a number of projections 211 spaced about the entry port, each projection having a groove or socket 212. The accessory holder lock is designed to accommodate a detachable transparent window device 213 shown in FIGS. 2 and 3A, and a detachable gland device 40 shown in FIGS. 4A and 48. Transparent window 213 may be constructed of a transparent material such as lucite, and is provided with lugs or teeth 214 designed to engage in gripping relationship with the corresponding grooves 212 of projections 211. Insertion of sighting device 213 is accomplished by rotating device 213 to engage lugs 214 in grooves 212, and removal is accomplished by rotating 213 to disengage lugs 214 from grooves 212. In addition, if desired, sighting device 213 may include a source of illumination 215 such as a conventional battery-bulb com bination 31.

In the spray coating operation, when the snake line is sighted within the gas main through window 213, window 213 is removed from saddle 21, the nozzle and hose are connected to the snake line, and gland device 40, which may be retained on the hose until the connection is made, is secured to saddle 21 by engaging lugs 41 of device 40 in grooves 212. In this fashion, except for the relatively brief time required to connect the snake line and the nozzle, gas is prevented from leaking out of the main, thereby permitting service to be maintained without interruption during the spraying operation.

If desired, the above-described

saddles

20 and 21 may be constructed of any one ofa number of materials such as metal or leather with suitable fastening means for securing the saddles to the exterior of the gas main. Further, saddle 21 may be provided with a permanently installed transparent section instead of a detachable window, in which case the presence of the snake line within the gas main may be sighted more easily by utilizing an exterior source of illumination such as a flashlight. In the event that saddle 21 is provided with a permanently installed transparent section, it is necessary to provide an additional saddle 20 which will accommodate a suitable gland at excavation l62 so that when saddle 21 is removed to permit connection and entry of the hose, saddle 21 may be replaced by saddle 20 to prevent the leakage of gas while the hose passes through the gas main in either direction.

With reference to the spray nozzle of this invention, this component is illustrated in FIGS. 5A and 58. At one end of the nozzle is a ring 51 for securing the nozzle to the snake line, while at the other end of the nozzle is a suitable hose coupler 52 which is inserted into the hose to secure the nozzle to the hose. Coating material that is pumped through the hose into the interior chamber 54 of the nozzle is forced out through a series of

holes

53a, 53b, 530 to spray the interior of the gas main. The holes are relatively small, being on the order of number 60 drill or 0.04 inch, and each series of holes extends around the entire nozzle so that no matter how the position of the nozzle varies as it is being drawn through the gas main, coating material will be sprayed onto the interior of the main and the caulking between joints.

The holes or orifices in each

group

53a, 53b, 530 are offset from one another in the manner shown in FIG. 5A to provide thorough spraying, and each group of orifices communicates with the interior chamber 54 at a different angle as shown in FIG. 5B. Thus each orifice in group 53a communicates with chamber 54 at an angle such that coating material is sprayed in the direction toward which the nozzle is being drawn by ring 51 through the gas main to contact the interior of the gas main at an acute angle measured in a clockwise sense from the pipe wall. For example, the axis of each orifice in group 53a intersects the longitudinal axis of the nozzle at an acute angle on the order of 70 so that theoretically the coating material will contact the interior of the gas main at approximately the same angle. Similarly, each orifice in group 53b communicates with chamber 54 at an angle such that coating material is sprayed in a direction perpendicular to the direction in which the nozzle is being drawn to contact the interior of the gas main at an angle of 90. Thus the axis of each orifice in group 53b intersects the longitudinal axis of the nozzle at a right angle. Finally, each orifice in group 53c communicates with chamber 54 at an angle such that coating material is sprayed in a direction opposite to that in which the nozzle is being drawn. For example, the axis of each orifice in group 53c intersects the longitudinal axis of the nozzle at an oblique angle on the order of 1 so that the coating material will meet the interior of the gas main at an acute angle on the order of 70 measured in a counterclockwise sense from the pipe wall. In this fashion, no matter how the caulking between joints faces the interior of the gas main, coating material will be effectively sprayed on it. Further, because the orifices in groups 53:: and 53c direct the coating material to meet the interior surface of the gas main at equal but oppositely oriented angles, the nozzle of this invention produces a uniform coating regardless of the direction in which the hose is drawn through the gas main while coating material is being sprayed. Also, it is apparent that additional groups of orifices may be provided, each group of orifices having axes oriented at a desired angle with respect to the longitudinal axis of the nozzle.

Turning now to FIG. 6, this drawing illustrates the improved reel structure for automatically rewinding a relatively light, flexible snake line of the type employed in this invention. The original portion of the reel structure is shown by dashed lines, while the structural elements provided by this invention are shown by solid lines. In prior applications of rodding machine 10, in which a snake line of ordinary weight and flexibility is employed, such a snake line is sufficiently rigid to coil itself automatically around the connected peripheries of vertically positioned, circular inner and

outer coiling elements

62a and 62b as the line is drawn in by a portable engine within machine 10 (not shown). Elements 62a and 6211 are shown in the drawing in generally dashed lines, but in fact the elements have thickness rather than just line thinness. However, it was discovered thata snake line sufficiently light and flexible to be useful in the present invention by being able to be urged through a section of gas main 500 feet or longer, was also too light and flexible to coil itself automatically around

elements

62a and 62b, thereby preventing a rapid spray coating operation by causing frequent stoppages to rewind the snake line on the reel manually. A solution to this problem was found by securing one end of each of a plurality of longitudinal guide members to different points of the inner circular member 62a and fastening together at a common point 64 the other end of each guide member, common point 64 being located relative to member 62a in the direction of the incoming snake line, and approximately on a line or axis passing through the central portion of circular members 620 and 62b. For example, if desired, four guide members 63-1, 63-2, 63-3, 63-4, which may be constructed of 0.5 inch metal rods, may be secured at points spaced apart at 90 intervals on inner circular member 62a. The guide members are directed from the inner circular member 62a toward the incoming snake line is made to slide along one or more of the guide members toward the circular members as the line is pulled in. Alternatively, the same result may be obtained by bending two relatively long metal rods into a semicircular or other curved shape and securing each rod at two different points, for example, diametrically opposite points on circular member 62a, with the central portions of the two rods being fastened to one another at common point 64.

FIG. 7 illustrates in detail the pumping equipment and hose reel which are ordinarily carried on a vehicle such as the truck 11 shown in FIG. 1. Sealing compound is carried within reservoir tank 701, tank 701 being filled preparatory to spraying by first attaching quick connecting coupler 704 to the source or vessel (not shown) from which sealing compound is to be obtained. Sealing compound is transferred to tank 701 by opening shut-off

valves

74, 70, and 73, and closing shut-off

valves

72, and 76, and control valve 71, following which variable speed motor 78 is actuated to drive pump 77. This configuration of opened and closed valves establishes a path for the sealing compound to be forced into tank 701 by way of valve 74, filter or strainer 706, transparent sight glass 79, pump 77, valve and valve 73. After tank 701 has been filled, motor 78 is shut off,

valves

70 and 74 are closed, and coupler 74 is disconnected from the sealing compound source. Valve 73 remains in the open condition during both filling of tank 701 with sealing compound and removal of sealing compound from tank 701 during the spraying of pipe interiors, valve 73 ordinarily being shut off to disconnect tank 701 from the remainder of the pumping equipment only during maintenance or repair of the pumping system.

Sealing compound is forced out of tank 701 during a spray coating operation by opening

valves

72, 71, and 76, and actuating motor 78 to drive pump 77, it being understood that

valves

70 and 74 are closed during the spray coating operation. Pump 77 causes sealing compound to be delivered from tank 701 to hose 12, through the duct path established by

valves

73 and 72, filter 76, sight glass 79, and

valves

71 and 76, the sealing compound pressure and flow rate being respectively measured by pressure gauges PGl, PGZ and flow meter FMl. Of course it is understood that prior to the delivery of sealing compound to hose 12, a suitable length of hose 12 and its associated nozzle have been unwound from hose reel 702 and positioned within the pipe to be spray coated in the manner described above.

The pressure at which it is desired to pump sealing compound through hose 12 is controlled both by varying the speed of motor 78 and by adjusting control valve 71. Pressure gauge P61 is ordinarily positioned to enable the operator of the pumping equipment to make an initial adjustment of pressure at the start of a spray coating operation, while pressure gauge PG2 is positioned to enable the operator to observe the pressure during the spray coating operation. The rate at which the sealing compound is flowing through hose 12 is measured by flow meter FMl, and by communicating with the operator sta tioned with the rodding equipment at the opposite extremity of the pipe to determine the rate at which hose 12 is being drawn through the pipe, the operator at the pumping equipment can calculate the amount of sealing compound being sprayed onto the interior of the pipe wall.

A conventional relief valve 75 is provided within a relief path leading back to tank 701 either directly or via valve 73, or as shown, both relief path arrangements may be employed. Filter 76 is of well known construction and removes impurities from the sealing compound by a double filtering action, once during the loading of sealing compound into tank 701 and again during removal of sealing compound in the spray coating operation. Visual observation of the flow of sealing compound is provided by transparent sight glass 79, which may be a section of transparent plastic pipe interposed at a suitable observation point within the system, for example, at a point within the duct between filter 76 and pump 77.

In order to maintain a homogeneous, well mixed sealing compound at all times, and in order to prevent freezing of the sealing compound during periods of low temperatures, the sealing compound is continuously agitated within as shown in FIGS. 8A and 8B, the interior of tank 701 is divided into chambers A and B by a vertical baffle plate 804 in which there are a number of openings, in order to minimize foaming and surging of the sealing compound within the tank. Within each chamber A, B there is respectively positioned a rotatable shaft 805-1, 805-2 onto which there are secured a number of impellers 806-1, 806-2. During an entire days spray coating operations, shafts 805-1, 805-2 are continuously rotated by means of a portable power source 800, for example, a conventional gasoline engine. Power is delivered to turn shafts 805-1, 805-2 by way of speed reducer 801 and drive belt 802 to pulleys 803-1, 803-2 attached to extensions of shafts 805-1, 805-2 exterior to tank 701. The continuous rotation of shafts 805-1, 805-2 causes impellers 806-1, 806-2 to agitate the sealing compound, thereby to maintain the compound in a thoroughly mixed condition at all times, as well as to prevent freezing of the compound.

Although this invention has been described in terms of spraying relatively long sections of underground gas main, it is to be understood that the present invention may be used for spraying the interiors of other kinds of piping systems. It is to be further understood that numerous modifications of the arrangement of the present invention may be devised by those skilled in the art without departing from the spirit and scope of the invention.

lclaim:

1. Apparatus for spraying in a single operation the interior of a relatively long section of gas main with a selected sealing compound to prevent and close leaks in the caulking between joints in said section, wherein at each of the two extremities of said section an opening is made in said gas main to gain access to said interior, which comprises:

means positioned at a first one of said extremities for automatically urging a snake line into and out of the interior of said gas main through said opening, wherein said snake line is sufficiently light and flexible to pass over obstructions and around curves in said section of gas main to reach the second one of said extremities locatable 500 feet distant from the first one of said extremities, and wherein said urging means includes reel means for automatically unwindling and rewinding said snake line for said automatic urging without manual assistance;

said reel means including an inner circular member about which said snake line is wound and unwound, a plurality of longitudinal guide members for said snake line and each of said guide members having one of its ends secured to an individual segment of said circular member, said guide members having respective second ends fastened together at a common point located relative to said inner circular member in a direction of an incoming of said snake line to said reel means and approximate to an axis passing through a central portion of said circular member, said guide members being effective in guiding the unwinding and rewinding of said snake line with minimal snake line tangling;

hose means terminated in a nozzle means positioned at the second one of said extremities, wherein said nozzle means is adapted to be connected to said snake line after said snake line has been automatically urged from said first extremity to said second extremity so that said hose means and said nozzle means are drawn through the interior of said gas main as said snake line is automatically rewound upon said reel means, and wherein said sealing compound is forced through said hose means and continuously sprayed out of a plurality of orifices in said nozzle means to contact the interior of said gas main simultaneously at a plurality of selected angles while said hose means and nozzle means are drawn through the interior of said gas main;

a first saddle means detachably secured to said first extremity of said gas main for preventing the leakage of gas from said opening at said first extremity while permitting said snake line to pass in and out of said gas main through said opening at said first extremity; and

a second saddle means detachably secured to said second extremity of said gas main for preventing the leakage of gas from said opening at said second extremity while permitting said hose to pass in and out of said gas main through said opening at said second extremity, wherein said second saddle means is provided with a transparent section which is positioned over said opening at said second extremity so that said snake line may be immediately detected by visual inspection through said transparent section upon the arrival of said snake line at said second extremity. 2. In a system for spraying in a single operation the interior of a relatively long section of gas main with a sealing compound to prevent and close leaks in the caulking between joints in said section, wherein at each of the two extremities of said section an opening is made in said gas main to gain access to said interior, and comprising:

means positioned at a first one of said extremities for urging a relatively light, flexible snake line into and out of the interior of said main through said opening thereat, to reach the second one of said extremities, and wherein said urging means includes reel means for automatically unwinding and rewinding said line; hose means terminated in a nozzle means and positioned at the second one of said extremities, wherein said nozzle means is adapted to be connected to said line after said line has been urged from said first extremity to said second extremity so that said hose means and said nozzle means are drawable through the interior of said main as said line is rewound upon said reel means, and wherein said sealing compound is forceable through said hose means and for continuously spraying out of said nozzle means to contact the interior of said main at a plurality of angles while said hose means is drawn through the interior of said main; and wherein said reel means comprises:

a first circular member having a first selected diameter: a second circular member having a second selected diameter smaller than said first selected diameter; means for rigidly connecting said first circular member to said second circular member in a vertical position so that said snake line can be coiled around the connected peripheries of said first and second circular members; and

a plurality of guide members, one end of each of said plurality of guide members being secured to a different one of a corresponding plurality of points on said second circular member, and the other end of each of said plurality of guide members being secured to a common point located on an axis passing through a central position of said first and second circular members so that said snake line is made to slide along one or more of said guide members on its way toward the connected peripheries of said first and second circular members.

3. Apparatus as defined in claim 2 wherein each of said plurality of guide members is formed into a selected curved shape, one end of each of said curved guide members being secured to a point onsaid second circular member, the other end of each of said curved guide members being secured to a diametrically opposite point on said second circular member, and the central portion of each curved guide member is secured to said common point.

4. Apparatus as defined in claim 2 wherein said nozzle means includes a plurality of groups of orifices comprising:

a first group of orifices that communicates with said interior chamber at a first selected angle such that said sealing compound contacts the interior of said gas main at a first selected acute angle measured in a clockwise sense from the interior of said gas main;

a second group of orifices that communicates with said interior chamber at a second selected angle such that said sealing compound contacts the interior of said gas main at a right angle; and

a third group of orifices that communicates with said interior chamber at a third selected angle such that said sealing compound contacts the interior of said gas main at a second selected acute angle measured in a counterclockwise sense from the interior of said gas main.

5. Apparatus for spraying in a single operation the interior of a relatively long 500 foot or longer section of gas main with a selected sealing compound to prevent and close leaks in the caulking between joints in said section, wherein at each of the two extremities of said section an opening is made in said gas main to gain access to said interior, which apparatus comprises:

means positioned at a first one of said extremities for automatically urging a snake line into and out of the interior of said gas main through said opening at said first extremity and said 500 foot or longer section of said main wherein said snake line is light and flexible to pass over obstructions and around curves in said 500 foot or longer section of gas main to reach the second one of said extremities, said last-mentioned extremity being 500 foot and more distant from said first extremity, wherein said urging means includes reel means with a guide device arrangement for automatically unwinding and rewinding said snake line for said automatic urging whereby said guide arrangement guides said snake line for a rewinding operation of said snake line:

said reel means including a first circular member having a first selected diameter, a second circular member having a second selected diameter smaller than said first selected diameter, and means for rigidly connecting said first circular member to said second circular member in a vertical position so that said snake line can be coiled around the connected peripheries of said first and second circular members;

said guide device arrangement including a plurality of guide members, one end of each of said plurality of guide members being secured to a different one of a corresponding plurality of points on said second circular member, and the other end of each of said plurality of guide members being secured to a common point located on an axis passing through a central position of said first and second circular members so that said snake line is made to slide along one or more of said guide members on its way toward the connected peripheries of said first and second circular members;

a first saddle means detachably secured at said second extremity to prevent leakage of gas from said opening at said second extremity during said urging of said snake line from said first to said second extremity, said first saddle means comprising means cooperating with said opening at said second extremity for providing for a humanly detectable indication of the arrival of said snake line at said second extremity upon said urging;

hose means terminated in a nozzle and positioned at the second one of said extremities, wherein said nozzle means is adapted to be connected to said snake line after said snake line has been urged from said first extremity to said second extremity so that said hose means and said nozzle are drawn through said first saddle means and the interior 500 or more foot section of said gas main as said snake line is rewound continuously upon said reel means, and wherein said sealing compound is continuously forced through said hose means and continuously sprayed out of a plurality of orifices in said nozzle means to contact said interior 500 and more foot section of said gas main simultaneously at a plurality of selected angles while said hose means and nozzle means are drawn through said interior 500 or more foot section of said gas main;

a second saddle means detachably secured to said first extremity of said gas main for preventing the leakage of gas from said opening at said first extremity while permitting said snake line to pass in and out of said gas main through said openirg at said first extremity; and further tnclu mg a device selective y connected to said first saddle means after the arrival of said snake line at said second extremity upon said urging through said interior 500 and more foot section of said gas main and thereafter cooperating with said hose means for preventing the leakage of gas from said gas main interior for said hose means drawing through said interior 500 and more foot section of said gas main.

6. Apparatus in accordance with claim 5 wherein said first saddle means cooperating with said opening at said second extremity includes a removable transparent section member which is positioned over said opening at said second extremity so that said line may be visually detected; and

a removable gland which replaces said transparent section member after said line is secured to said nozzle means, and which prevents leakage of gas while said hose means is drawn through said gland and said opening at said second extremity.

7. Apparatus in accordance with claim 5 wherein said first saddle means cooperating with said opening at said second extremity includes a transparent section member which is positioned about said opening at said second extremity so that said snake line may be visually detected within the interior of said main,

and further comprising auxiliary saddle means including means for detachably securing said auxiliary saddle means to said gas main at said second extremity after said first saddle means has been removed from said main, and gland means for preventing the leakage of gas while said hose means is drawn through said gland and said opening at said second extremity,

and wherein said auxiliary saddle means replaces said first saddle means after said line is secured to said nozzle means.