US1327268A - Method of sealing crevices in rock formations - Google Patents

Description

G. W. CHRISTIANS. METHOD OF 'SEAL ING CREVICES IN ROCK FORMATIONS.

APPLICATION FILED JUNE 9. I919.

Patented Jan. 6, 1920;

i E rarns r'rn GEORGE W. CHRISTIANS, OF CHAT'IANOOGA, TENNESSEE.

- METHOD OF SEALING CREVICES IN ROCK-FORMATIONS.

Specification of Letters Patent.

Patented J an. 6, 192%.

Application filed June 9, 1919. Serial No. 302,795;

cool, through a suitably heated pipe into the rock containing the crevices or cavities.

' After reaching the rock formation, the sealing material sure and then becomes cool and practically solid, thus filling the crevices and effectually sealing said crevices against the passage of water and the like.

I have found from practical operations that a number of different materials, such as sulfur, asphalt or coal tar pitch, may be a used, but I believe that unadulterated asphalt'is the best [material for the process.

It has heretofore been proposed'to introduce bitumen, pitch and sulfur into'creviced rock for the purpose of sealing the interstices but the method of introducing such materials is essentially diflerent from my process and it has never been used to commercial advantage.

Cement has also been used prior to my invention'for filling rock crevices and it may be of assistance at this stage to point out the advantages of my method over the cement grouting method. First, my method can-be successfully employed, for sealing crevices or a cave of considerable size, through which water is flowing at relatively high velocity, without loss of material by washing. In grouting, great quantities of cement are oftenwashed away and wasted before a closure is effected and then it is frequently impossible to determine whether the crevice is sealed or whether the drilled holehas be-' untll a high resisting pressurehas been enters the crevices under presand is strong enough reached a definite assurance'is obtained that all spaces adjacent to the pi e line are filled. Grouting can only be effective at one point at a time and when the introduction of the cement at this point is finished, a new hole must be drilled. Third, with my method, after the Work is completed at any particular hole, the pipe together with a portion of the heating means are left embedded in the sealing material, so that if it is considered desirable at some future time (several years later if necessary) more material may be forced into the same hole' by merely making the proper connections with the pipe and heating means. :lhen after'heating for a few minutes, additional material may be introduced, the same as if the .original operation had never been halted. When grouting, on

the other hand, a stoppage of only a few minutes allows the cement to set in the hole and consequently no more cement can be inserted. Owing to this solidifying of the cement, a new hole must be drilled if it is de- I sired to continue the work.

Before proceeding with a detail description of the process, it may be well to mention some practical observations had during recent successful demonstrations of my method. It has been found in practice that pitch and asphalt are very poor conductors of heat and this fact very greatly assists the operation. In my process, an electrical conducting wire extends through the pipe for the purpose of maintaining the material in heat ed condition during its passage through the pipe, and the asphalt or pitch which sur-' rounds the wire, efiectually insulates the a wire from the pipe, both electrically and' thermally, so that while the pipe may be cold yet very little heat is required to maintain a fluid passage adjacent the wire. As soon as the sealing material leaves the pipe and touches the Water in the crevicethe surface of the material hardens into .a tough skin, but the heat conductivity is so poor, that the interior of the material remains hot I and fluid. The hardened skin forms a tough sack which clings to the opening in the pipe to resist the pressure of p a considerable velocity of water or the like,

but the inside of the sack and a connection between the'opening in the pipe and the inside of the sack remains fluid as long as a continuous flow is maintained, so that the sack can be expanded indefinitely, unless obstructed, with very little pressure. This enmelting point, such as unadulterated asphalt, may be successfully used.

With a view of more clearly setting forth the invention, reference may be had to the accompanying drawing,which illustrates a .part of theapparatus forming the subject matter of an application filed of even date herewith and bearingSerial Number 302,796.

In the drawing: Figure 1 is a diagrammatic view of the apparatus illustrating the manner of introducing the heated sealing material into the rock crevices under pressure. I

Fig. 2 1s a detail vlew of the materlal conductin pipe.

In tile drawing 1 represents a supply tank -or reservoir in which the hot sealing ma terial such as pitch or asphalt is stored. A pipe 2 connects this tank with a heating chamber 3 in.which the material is kept heated by means of suitable burners 4. A .pump 5 is located in the. heating chamber and is maintained in heated conditionby being submerged in the sealing material contained in the chamber 3. The pum is driven from a suitable power means not shown) through the medium of the belt 6 and it is adapted to draw the hot material from the chamber 3 and force the same with considerable pressure into the pipe 7. 'The pipe 7 is provided with a suitable pressure gage 8 and located within the pipe is a heating wire 9, which is connected to an electric supply line wire 10; One end of the wire is connected by a suitable yielding device, such as a coil spring 11, to a fixed or stationary point" 12, and the other end of the wire is fixed to a terminal of connector 29 which bears against. an insulated plug 13, carried,

by one arm of a cross-shaped pipe fitting 14.. The spring 11 maintains the wire 9 taut in the pipe 7 The other wire 15 of the supply line is in electrical connection with the pipe 7.

A second pipe-16 is connected to the fitting 14 and is extended down into, a previously drilled hole 17, which communicates with the crevices or cracks 18 that are to be filled or sealed. The pipe 16 is made up of anumber of sections 19 connected together by couplings 20 and it carries at its lower end a point 21; As will be seen from the drawing, the sections of the pipe 16, which are adjacent the crevices 18 are provided With a series of apertures 22 and located between the adjacent ends of the pipe sections 19 are insulating washers. 23, which aid in maintaining an electric circuit through the pipe 16. This wire 24 is connected at its lower end 25 to the point 21 and its upper portion extends with a free lit through an which has its upper end fixed to a stationary support 28,- and this spring tends to maintain the wire 24 taut and out of electrical connection with the inner surface of the pipe 16. An electric conducting wire 29 connects the wires 9 and 24 together, so that v the electric current from the line wire 10 passes through the Wires 9, 29 and 24 in the I order named to the point 25, then along the pipes 16 and 7 back to the line wire 15. It will-be understood thatthe wires 9 and 24 are highly heated by the electric current and that they maintain the interiors of the pipes .7 and 16 in heated condition, so that sealing material passing through said pipes will be kept in heated condition until it passes out through the apertures' inthe pipe 16.

With the abovedescribed apparatus my method is carried out as follows: A suitable sealing material, which is fluid when heated but nearly solid and extremely viscous when cool, is placed in thevreservoir 1. A number of different materials such as sulfur, asphalt or coal tar pitch may be employed but it is necessary that the material have a moderately low melting point, that it be an insulator of electricity, and that it be not absolutely solid and non-fluid'when cohled. Unadulterated as halt is probably the most practical material It may be desirable to vary the consistency of the ma' terial so that when cooled it may be made more or lessfiliid. -With asphalt, this can be done-by the addition of a small percentage of crude oil. The character of the ma terial used depends upon the conditions encountered. It is necessary that the material bestifi enough to resist any pressure tending to push it out of the crevice (such as the head water of a dam) but it must be fluid enough so that a moderate hydraulic pressure will force it the necessary distance into the crevice or crevices.

'through the apertures in the pipe 16, the

material acquires .a thick skin, and the heated material passing from the pipe enters this skin and maintains the interior of the skin in hot fluid condition while the skin is being expanded by the pressure on the materials After the crevices are filled, the electric current is cut oil and the material is permitted to cool and solidify. Then the fitting 14 is disconnected from the pipe 16 that various changes,

.of any depth.

and connected to another pipe which is used in operating on a second hole.

The operation of filling a crevice may be continuous or intermittent and as many stoppages may occur as" are desirable. When shut down, the electric current is cut off and the material in the pipe line is in substantially solid condition. When starting up again, the current is turned on and in a few minutes the material in the pipe line will be heated and liquefied and ready to be pumped.

The pipe lines can be made of One inch extra heavy pipe, cut in five foot lengths with a coupling containing a, lava insulating washer between each length of pipe. The pump may be located at any convenient place and the material piped for any reasonable distance to the opening of the drill hole and down the hole to the crevices. Where the pipe line passes through the crevices or porous formation, it is preferably perforated at 22 with three-quarter inch holes at three inch centers so that the material can flow out into the opening. The hot Wire passing down through the pipe maintains a fluid passage so that the pressure is equalized throughout its whole length, and one material is free to expand at the points of least resistance. Where it is necessary to change the direction of the pipe line, suitable insulating fittings 14, a connector for the wires 29 and strong and 2-7 to keep the wire taut, must be provided.

The holes down which the pipe line runs may be drilled with diamond or shot core drills or with churn type drills, and need only be two inches in diameter, and can be For waterproofing the foundation of a dam, they should be spaced at regular intervals at such a distance that the material expanded into a crevice from one. will meet the asphalt expanded from the 'next, and so make a complete seal. The holes may be drilled at twelve foot centers and the material pumped into them one after another.

, While I have described the most essential details of-my method, it will be understood that the steps of the method need not be followed in the order named. I am aware modifications and differentiations may be made inthe method without departing from the spirit of the invention as outlined in the followmg claims.

What I claim and desire to secure by Letters Patent is 1. The method of sealing crevices in fissured rock formations consisting in extending a conduit to the place where a. crevice occurs, forcing a material which is fluid when heated but nearly solid when cool,

tension springs 11 through said conduit and into said crevice, generating heat within the conduit, and utilizing the heat generated forv maintaining the material in heated condition during its passage through said conduit and into said crevice.

2. A method of sealing a crevice under ground, which consists in drilling a hole to the place where the crevice occurs, placing a conduit having a perforated wall in said hole with the perforations adjacent said crevice, forcing a, material which is fluid when heated and nearly solid when cool, through said conduit and perforations, and into saidcrcvice, generating heat within the conduit, and utilizing the heat generated for maintaining the material in fluid and heated condition during its travel through said conduit and perforations and into said crevice.

3. A method of sealing crevices in fissured rock formations, winch conslsts in extend in a pipe provided with apertures into the a rock formation and arranging the perforations adjacent said crevices, introducing a material, which is fluid when heated and nearly solid when cool, under pressure through said pipe and perforations into said crevices. generating heat Within the. pipe, and utilizing the heat generated for maintaining the materialin heated fluid condition during its travelthrough said pipe and perforations into said crevices.

4. A method of sealing a crevice in a fissured rock formation, consisting in drilling a hole through the rock tosaid crevice, inserting a pipe having a perforated portion into said hole and arranging the perforations of the pipe adjacent the crevice, forcing under pressure a material, which is fluid when heated and nearly solid when cool, through said pipe and perforations into said crevice, generating heat within the pipe, and utilizing the heat generated for maintaining said material in fluid condition during its' passage through the pipe and perforations into said crevice. I

5. A method of sealing interstices in under ground'formations, which consists in drilling a hole to the point Where the inter stices occur," inserting a perforated pipe'into said hole and arranging the perforations of the pipe adjacent said interstices, forcing asphalt in fluid condition and under pressure through said pipe and perforations and into said interstices, generating heat within the pipe, utilizlng'the, eat generated for mainta ning the asphalt in heated condition until it is lodged in said interstices, and permitting the asphalt to 0001.

In testimony whereof I have hereunto affixed my signature. v GEORGE W. CHRISTIANS.

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