US3729054A - Rejuvenation of wells and other ground-water collecting devices - Google Patents

Abstract

A drilled well of deficient performance due to accumulation of scales on the water-intake parts of its well pipe is rejuvenated at low cost by inserting a cleaning pipe of smaller diameter through the well pipe to supply concurrently to the water-intake parts an aqueous solution of a harmless washing agent and highpressure air, which produce a cooperatively combined agitation action by which the scales are chemically dissolved, loosened, and washed off and can be subsequently removed by pumping through the well pipe. The air and solution are delivered from respective supply pumps and supplied through a mixer to the cleaning pipe to be ejected with high energy through a vaned turbine wheel at the lower end of the cleaning pipe.

Description

United States Patent [191 Yokoyama 1 REJUVENATION OF WELLS AND OTHER GROUND-WATER COLLECTING DEVICES [75] lnventor: Kashimi Yokoyama, Hiroshima,

Japan [73] Assignee: Suiri Kogyo Kahushiki Kaisha, Hiroshima, Japan [22] Filed: Mar. 23, 1971 [21] Appl. No.: 127,124

[30] Foreign Application Priority Data Dec. 28, 1970 Japan ..45/119633 [52 us. Cl ..166/312 [51] ..E2lb 21/00 [58] Field of Search ..166/312, 305 R, 222, 166/223, 67

[56] References Cited UNITED STATES PATENTS 2,768,694 10/1956 Moll .,l66/312 X 2,740,476 4/1956 DAudiffret ..166/305 R 2,126,575 8/1938 Renney ..166/305 R X [1 1] 3,72%,054 45] Apr. 24, 1973 Primary ExaminerRobert L. Wolfe AtmrneyHolman & Stern l 5 7 ABSTRACT A drilled well of deficient performance due to accumulation of scales on the water-intake parts of its well pipe is rejuvenated at low cost by inserting a cleaning pipe of smaller diameter through the well pipe to supply concurrently to the water-intake parts an aqueous solution of a harmless washing agent and highpressure air, which produce a cooperatively combined agitation action by which the scales are chemically dissolved, loosened, and washed off and can be subsequently removed by pumping through the well pipe. The air and solution are delivered from respective supplypumps and supplied through a mixer to the cleaning pipe to be ejected with high energy through a vaned turbine wheel at the lower end of the cleaning pipe.

3 Claims, 13 Drawing Figures Patented April 24, 1973 5 Sheets-Sheet 1 FIG.

Patented April 24, 1973 3,729,054

5 Sheets-Sheet 2 Patented April 24, 1973 3,729,054

5 Sheets- Swat 5 FIG-7(0) FIG.7(b)

Patented April 24,1973 3,729,054

5 Sheets-Sheet 4 FIGBW TO PUMP ooooo oooo o 1 WATER Patented April 24, 1 973 5 Sheets-Sheet .5

F I G. lO(b) REJUVENATION OF WELLS AND OTHER GROUND-WATER COLLECTING DEVICES BACKGROUND OF THE INVENTION This invention relates generally to wells and more particularly to a new and advanced process and apparatus for rejuvenating or reconditioning wells and other devices for obtaining ground water which are deficient in performance because of accumulation of scales on their water-intake parts. The invention is particularly effective and useful in rejuvenating water wells for obtaining potable water, industrial water, and water from springs such as hot springs and cold mineral-water springs.

Among the facilities known from the past for obtaining water from water sources for water pipeline service in cities, towns, and villages and in enterprises of various kinds and sizes, the most widely used facilities for obtaining ground water and intermediate infiltration water and river-bed water have been drilled wells (known also as bores, borings, tube wells, and bore-hole wells) and dug wells each lined with a sunken casing such as a so-called Hume concrete pipe with a perforated bottom part or adrilled well pipe provided with a strainer at its lower end.

As is known, the operation including that of these wells in obtaining water comprises collecting the source water flowing underground, pumping this water as collected into a reservoir once, and purifying this water by a chemical solution treatment, chlorine pretreatment, or any of various filtration methods to remove iron, manganese, turbidity, and various kinds of coagulated impurities thereby to render the water into clear potable water or industrial water.

Since it has not been possible to carry out underground this purification and treatment of the source water, scales due to impurities contained in the source water are deposited and accumulate on the water-intake parts of these facilities for obtaining source water and in closely neighboring regions, whereby the performances of these facilities, which entail high manufacturing and installation costs, drop year by year. The present state of the art is such that these facilities must for this reason be abandoned or reinstalled at high cost after only a relatively short time of a few years to ten years or somewhat more.

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above described difficulty by utilizing certain findings I have made as described hereinafter.

More specifically, an object of the invention is to provide a simple and low-cost process for removing accumulated scales as described above whereby devices for obtaining ground water of lowered performance due to scales can be economically rejunevated.

According to the present invention, briefly summarized, there is provided a process for removing such scales which is characterized by the steps of supplying concurrently an aqueous solution of a harmless washing agent and air at a high pressure to and through the water-intake parts of the water-obtaining device thereby to cause disintegration, loosening, and washing off of the scales by the cooperatively combined agitation action of the solution and air and thereafter operating the device to pump and remove water containing the scales thus washed off.

According to this invention in another aspect thereof, there is provided an apparatus for carrying out the above stated process, this apparatus being characterized by the combination of first and second pumps for delivery, respectively, of the wash solution and the high-pressure air, mixing means for mixing the solution and air thus delivered to produce a mixture thereof, a pipe connected at one end to the mixing means and functioning to supply the mixture into the water-obtaining device, and ejection means connected to the other end of the pipe and operating to eject the mixture with great energy against the water-intake parts thereby to cause the disintegration, loosening, and washing off of the scales.

The nature, principle, details, and utility of the invention will be more clearly apparent from the following detailed description with respect to preferred embodiments of the invention when read in conjunction with-the accompanying drawings, in which the same or equivalent parts are designated by the same reference numerals and characters.

I BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a diagrammatic elevation showing the essential parts and organization of a drilled well for obtaining ground water;

FIGS. 2 and 3 are, respectively, a fragmentary elevation and a sectional plan view indicating the state of deposition of scales on the water-intake parts at the lower part of the well pipe of the well shown in FIG. 1;

FIGS. 4, 5 and 6 are views similar to FIGS. 1, 2, and 3, respectively, indicating the disintegration and washing off of scales around the outer periphery of a well pipe by the cooperatively combined agitation of an aqueous solution and high-pressure air in accordance I with the invention;

FIGS. 7(a) and 7(b) are, respectively, a diagrammatic elevation and a fragmentary plan view indicating the state of deposition of scales around a gallery or adit extending horizontally from a dug well;

FIGS. 8(a) and 8(b) are respectively a diagrammatic elevation and a fragmentary plan view indicating the state of deposition of scales on the bottom periphery of a dug well,

FIG. 9 is a diagrammatic elevation, partly in section and with parts cut away, illustrating a specific example of apparatus according to the invention for carrying out the process thereof; and

FIGS. 10(a) and 10(b) are, respectively, a relatively enlarged elevation in vertical section and a plan view of a vaned turbine wheel rotatably supported on the lower end of the pipe for supplying the wash solution and high-pressure air.

DETAILED DESCRIPTION As a result of observations of actual phenomena in the development of the present invention, 1 have verified that the cause of the coagulation, deposition and accumulation of scale on the outer periphery of a well pipe is as follows.

When the quantity of the source water passing through a strainer 3 at the bottom end part of a drilled well pipe I, for example, as shown in FIG. 1 decreases, the dynamic water-level drop on the suction side of pump 4 as indicated by curve 7 due to a water-level drop 6 cause a substantial lowering of the pump performance, and the concentration of impurity substances in the source water existing stagmently around the outer periphery of the strainer pipe 3 progressively increases, the impurities adhering and accumulating with the highest concentration thereof around the outer periphery of the well pipe and becoming progressively less concentrated in the radially outward direction with a conical distribution pattern as indicated in FIGS. 1, 2, and 3.

In accordance with the present invention, a waterobtaining device in the above described state of contamination by scales is rejuvenated in the manner described hereinbelow with respect to a drilled well constituting a specific example.

The conventional pump 4 is disconnected from the upper end of the well pipe 1, and a combination of a pump 8 for supplying an aqueous solution ofa harmless washing agent and an air-supplying device 9 for supplying air at high pressure is installed for intercoupled operation at the upper end of the well pipe I as illustrated by one example as shown in FIG. 4, and a pipe 10 is inserted through the well pipe 1 to supply the wash solution and high-pressure air to the bottom end ofthe well pipe I.

As a result, the oxygen within the high-pressure air and the solution produce a cooperatively combined agitation action by which the deposited scale 5 is disintegrated and washed off.

Thereafter, the conventional pump 4 is reconnected to the upper end of the well pipe 1 and operated for a period sufficient to pump out all contaminated water resulting from the above described rejuvenation process. The well thus reconditioned can then be operated in the ordinary manner with a performance higher than that prior to the rejuvenation process.

In accordance with this invention, there is further provided an apparatus for carrying out the above described process. In a specific example of the apparatus, as illustrated in FIGS. 9 and 10, the aforementioned pipe 10 is provided at its lower end with a vaned wheel 25 rotatably supported by the pipe 10 in a manner permitting free rotation of the wheel about a vertical axis. The lower end of the pipe 10 communicates with the interior of the wheel 25 through a central inlet port at the upper part of the wheel. The interior of the wheel is provided with vanes 25a and has a peripheral outlet opening 26. The maximum diameter of the vaned wheel is less than the inner diameter ofa well pipe 1 which is to be cleared, and means (not shown) are provided to center the wheel 25 with respect to the axis of the well pipe 1 thereby to prevent contact therebetween.

The pipe 10 with the vaned wheel 25 is inserted into a well pipe I after the pump device 4 has been disconnected, the upper end of the pipe 10 being connected by way of a flexible pipe 27 to a supply device 32 for supplying a wash liquid and high-pressure air. This supply device 32 comprises essentially a high-pressure air pump 33, a wash-liquid supply pump 34, and a mixer 35 connected to the delivery outlets of the air pump 33 and wash-liquid pump 34 and operating to mix the air and wash liquid and to deliver the resulting mixture to the pipe 10 through the flexible pipe 27. The pumps 33 and 34 are powered by respective motive means 330 and 34a.

The apparatus of the above described organization according to the invention is used and operates in the following manner. The pipe 10 is first installed within the well pipe 1 at a depth such that the varied wheel 25 5 is positioned at a level in the neighborhood of the strainer 3. The motive power means 330 and 34a are then started to operate the pumps 33 and 34. Highpressure air delivered by the air pump 33 and the wash liquid delivered by the wash-liquid pump 34 are thereupon mixed within the mixer 35, and the resulting mixture is supplied through the pipe 10 and enters the vaned wheel 25.

The mixture thus supplied into the vaned wheel 25 causes the wheel to rotate at a high speed depending on the kinetic and pressure energy of the mixture itself. The wash liquid mixed up completely with the air, is thereby ejected with great force toward the inner wall surface of the strainer 3 by centrifugal force due to the rotation of the vaned wheel 25 and disintegrates and washes off scale in cooperation with the oxygen within air as described hereinbefore.

This washing operation is preferably carried out as the pipe 10 is reciprocated up and down so that the vaned wheel 25 traverses through the total length of the strainer 3, that is, between levels 28 and 29 indicated in FIG. 9. By this procedure the scale adhering to the strainer and its neighborhood can be throughly removed.

While the invention has been described above with respect to one example of application thereof to a drilled well, its application is not so limited but includes that to a dug well with a casing having a perforated bottom part as illustrated in FIGS. 8(a) and 8(b), in which the accumulation of scales is designated by reference numeral 13. Another example of application of the invention is that to a dug well with a perforated gallery or adit extending horizontally from the lower part thereof through a region in the river bed of a river 12 as shown in FIG. 7(a). In this case, the scale accumulation assumes a distribution as indicated at l 1 in FIG. 7(b).

A well or like water-obtaining facility contaminated by an accumulation of scales can be thus rejuvenated in accordance with the invention at a cost which has been estimated to be from one-third to one-fifth the cost of installing a new facility.

I claim:

1. Apparatus for removing scales adhering to waterintake parts of a ground-water collecting well comprising, in combination, a first pump for delivering an aqueous solution of a harmless washing agent, a second pump for delivering high-pressure air, means for mixing the aqueous solution and air thus delivered to produce a mixture thereof, a pipe connected at one end to said mixing means and extending downward through the well to terminate at the other end near the water-intake part to supply the mixture into the ground-water collecting well, and a vaned turbine wheel rotatably supported on the other end of the pipe for rotation about a vertical axis by the energy of said mixture supplied therein to through the pipe and having a central inlet and a peripheral outlet for flow of the mixture and radial ejection thereof under centrifugal force against the scales, the ejection of the mixture causing disintegration, loosening, and washing off of the scales by the cooperatively combined agitation action of the washing agent and the air and by chemical action of the washing agent against the scales.

2. The apparatus as claimed in claim 1 in which said mixing means includes means for spraying the aqueous solution into the flow of the high pressure air.

3. The apparatus as claimed in claim 1 in which said pipe and hence said turbine wheel are reciprocable up 5 and down along the water-intake part of the well.

Claims (3)

1. Apparatus for removing scales adhering to water-intake parts of a ground-water collecting well comprising, in combination, a first pump for delivering an aqueous solution of a harmless washing agent, a second pump for delivering high-pressure air, means for mixing the aqueous solution and air thus delivered to produce a mixture thereof, a pipe connected at one end to said mixing means and extending downward through the well to terminate at the other end near the water-intake part to supply the mixture into the ground-water collecting well, and a vaned turbine wheel rotatably supported on the other end of the pipe for rotation about a vertical axis by the energy of said mixture supplied therein to through the pipe and having a central inlet and a peripheral outlet for flow of the mixture and radial ejection thereof under centrifugal force against the scales, the ejection of the mixture causing disintegration, loosening, and washing off of the scales by the cooperatively combined agitation action of the washing agent and the air and by chemical action of the washing agent against the scales.

2. The apparatus as claimed in claim 1 in which said mixing means includes means for spraying the aqueous solution into the flow of the high pressure air.

3. The apparatus as claimed in claim 1 in which said pipe and hence said turbine wheel are reciprocable up and down along the water-intake part of the well.

Images