Placement of fluids in ground by pulse-injection

• US 8,166,992 B2
• Filed: 09/25/2007
• Issued: 05/01/2012
• Est. Priority Date: 09/25/2006
• Status: Active Grant

• Current Assignee: Wavefront Reservoir Technologies Ltd.
• Original Assignee: Wavefront Reservoir Technologies Ltd.
• Inventors: Samaroo, Mahendra
• Primary Examiner(s): Lee, Kevin
• Application Number:
  US12/441,942
• Publication Number:
  US 20100065124A1
• Time in Patent Office: 1,680 Days
• Field of Search: 137/269, 137/565.01, 137/624.13, 137/1
• US Class Current: 137/1
• CPC Class Codes: B09C 1/002 involving in-situ ground water treatment
• CPC Class Codes: B09C 1/02 Extraction using liquids, e.g. washing, leaching , flotation
• CPC Class Codes: E21B 37/00 Methods or apparatus for cleaning boreholes or wells E21B21/00 takes precedence
• CPC Class Codes: F16K 31/041 for rotating valves F16K31/055 takes precedence
• CPC Class Codes: Y10T 137/0318 Processes
• CPC Class Codes: Y10T 137/5109 Convertible
• CPC Class Codes: Y10T 137/85978 With pump
• CPC Class Codes: Y10T 137/86405 Repeating cycle

Abstract

For use when injecting remediation liquid via an injection-well into contaminated groundwater, in the ground. The injection equipment includes a pulse-generator, which has an upstream chamber and a downstream chamber, linked by a pulse-conduit and a bypass conduit. The pulse-conduit includes a pulse-port, which opens and closes cyclically. The pulse-port is formed by the interaction of two apertures, one in the motorised rotor, the other in the stator. The rotor and stator may be formed as two facing plates held slightly apart, or as two cylinders one inside the other. The pulse-generator is located at the ground surface and can be adjusted as to pulse frequency, pulse amplitude, pulse rise-time, and as the the differential pressure between the upstream-chamber and the downstream chamber.

Claims

1. An operable fluid-injector, which is operable in combination with a body of ground and an injection-well located in the body of ground, wherein:

the injection-well is so arranged as to conduct a flow of fluid down an in-ground pipe of the injection-well, and to inject the fluid therefrom out into the ground formation around the injection-well;

the fluid-injector is located at the ground surface;

the fluid-injector is effective, when operated, to increase the concentration of the injected fluid in groundwater in the formation around the injection-well;

the fluid-injector includes a pulse-generator, for superimposing pulses onto the flow of fluid down the in-ground pipe;

the pulse-generator is mounted at ground surface level;

the pulse-generator includes a housing, in which is mounted an electric motor, having a rotating drive-shaft;

the pulse-generator includes a rotor, which is drive-coupled to the drive-shaft, and a stator;

the housing defines an upstream-chamber, which has an inlet-port for receiving fluid from a supply reservoir;

the housing defines a downstream-chamber, which has an outlet-port for conveying fluid to the in-ground pipe;

the housing includes a pulse-conduit, containing an openable and closable pulse-port;

the pulse-conduit is structured for conveying fluid, when open, from the upstream-chamber to the downstream-chamber;

the rotor is provided with a rotor-aperture, and the stator is provided with a stator-aperture;

the rotor-aperture and the stator-aperture are so arranged that, as the rotor rotates, the rotor-aperture cyclically covers and uncovers the stator-aperture;

the pulse-port of the pulse-conduit is fully open when the rotor-aperture fully overlies the stator-aperture, is partially open when a portion of the rotor-aperture overlies a portion of the stator-aperture, and is closed when no portion of the rotor-aperture overlies any portion of the stator-aperture;

whereby, insofar as the upstream-chamber at a higher pressure than the downstream-chamber, and insofar as the motor rotates, a pulse comprising a pressurised pulse-volume of liquid passes from the upstream-chamber to the downstream-chamber, through the pulse-conduit, when the pulse-port is open.

2. The fluid-injector of claim 1, wherein:

the housing includes a bypass-conduit, which is structured for conveying fluid from the upstream-chamber to the downstream-chamber, separately from the pulse-conduit;

the pulse-generator is so arranged that;

(a) when the pulse-port is closed, the upstream-chamber is in fluid-conveying communication with the downstream-chamber only via the bypass-conduit; and

(b) when the pulse-port is open, the upstream-chamber is in fluid-conveying communication with the downstream-chamber via the bypass-conduit and additionally via the pulse-conduit.

3. The fluid-injector of claim 1, wherein:

the apertures that form the pulse-port are surrounded, when the pulse-port is fully closed, by respective marginal areas;

the marginal areas thereof include respective small-gap-areas;

each small-gap-area constitutes a complete unbroken encirclement of its respective aperture;

over the whole small-gap-area, respective surfaces of the rotor and the stator lie in face-to-face opposition, with a gap therebetween; and

at no point around the complete unbroken annular encirclement of the aperture is the gap larger than a hundred microns.

4. The fluid-injector of claim 1, wherein:

the housing includes a bypass-conduit, which is structured for conveying fluid from the upstream-chamber to the downstream-chamber, separately from the pulse-conduit;

the pulse-generator includes a first choke and a second choke;

the first choke is assemblable into a choke-receptacle, having a through-hole of an area CA1 sq.cm, which defines the smallest fluid-conveying cross-sectional area of the bypass-conduit between the upstream-chamber and the downstream-chamber;

the choke and choke receptacle are so structured that the receptacle can be opened and the first choke removed, and replaced by the second choke; and

the second choke has a through-hole area of CA2 sq.cm, CA2 being not equal to CA1.

5. The fluid-iniector of claim 1, wherein the pulse-generator includes structure that is so configured as to enable adjustment of the frequency at which pulses pass through the outlet-port.

6. The fluid-infector of claim 5, wherein:

the pulse-generator includes an operable motor speed control, which is effective, when operated, to adjust the speed of rotation of the electric motor;

the pulse-frequency adjuster additionally includes a kit comprising either;

(a) the said rotor, with its rotor-aperture, and a second-rotor, having two or more rotor-apertures, the second-rotor being interchangeable with the said rotor in the pulse-generator;

or

(b) the said stator, with its stator-aperture, and a second-stator, having two or more stator-apertures, the second-stator being interchangeable with the said stator in the pulse-generator;

or

(c) both.

7. The fluid-infector of claim 1, including an operable pulse-amplitude-adjuster, which is effective, when operated, to change the amplitude of the pulses.

8. The fluid-infector of claim 1, including an operable pulse-rise-time-adjuster, which is effective, when operated, to change the rise-time of the pulses.

9. The fluid-infector of claim 1, including an operable differential-pressure adjuster, which is effective, when operated, to change the difference between the pressure in the upstream-chamber and the pressure in the downstream-chamber that obtains when the pulse-port is fully closed.

10. The fluid-infector of claim 1, wherein:

the pulse-generator includes an accumulator, having a liquid-storage-volume, which includes the volume of liquid that is in the upstream-chamber and that communicates with the upstream chamber through an accumulator port;

the liquid-conveying cross-sectional area of the accumulator-port is at least as large as the liquid-conveying cross-sectional area of the pulse-port when fully-open;

the accumulator includes a resilience

the resilience has such physical characteristics as to have the capability, during rotation of the rotor, of maintaining liquid in the upstream-chamber at a pressure of at least half the level of pressure that obtains in the upstream-chamber when the pulse-port is partially open but is on the point of closing, as when the pulse-port was fully-closed.

11. The fluid-injector of claim 1, wherein:

the rotor includes a rotor-flat-surface, into which the rotor-aperture is formed;

the stator includes a stator-flat-surface, into which the stator-aperture is formed;

the pulse-generator is so arranged that the stator-flat-surface and the rotor-flat-surface lie in face-to-face opposition, being separated by a gap of not more than a hundred microns.

12. The fluid-injector of claim 11, wherein:

the rotor-plate is rigidly fixed to the drive-shaft, and the drive shaft is guided for rotation by means of a rolling bearing assembly;

the bearing assembly includes two rows of balls, which run in respective inner and outer race-ways;

the two outer race-ways are formed in a single unitary outer race; and

the two inner race-ways are formed in a single unitary inner race.

13. The fluid-injector of claim 12, wherein:

the housing includes a cap and a base, which are held together, during operation, in that respective abutment surfaces of the cap and base are held together by an operable fastening means;

the cap is separable from the base for the purposes of disassembling the pulse-generator, by operating the fastening means, and then separating the abutment surfaces;

the bearing assembly is fixed into the cap;

the manner of mounting of the bearing assembly into the cap, of the drive-shaft into the bearing, and of the rotor-plate to the drive-shaft, is such that, when the cap is removed from the base, the bearing assembly, the drive-shaft, and the rotor-plate remain with the cap;

whereby the drive-shaft and the rotor-plate remain equally firmly secured relative to the cap when the cap is removed from the base as they were secured when the cap was fastened to the base.

14. The fluid-infector of claim 13, wherein:

the drive-shaft includes a flat shoulder, lying at right-angles to the axis of the shaft, against which a flat surface of the rotor-plate can be held by means of an operable rotor-fastener;

the pulse-generator includes a second-rotor-plate, having an equivalent second-flat-surface, and having a different configuration of rotor-aperture from the said rotor-plate;

whereby, when the rotor-fastener is operated, the said rotor-plate can be removed from the shaft, and substituted by the second-rotor-plate.

15. The fluid-infector of claim 1, wherein:

the rotor includes a rotor-cylinder, into which the rotor-aperture is formed;

the stator includes a stator-cylinder, into which the stator-aperture is formed;

the cylinders are configured for relative rotation, one inside the other.

16. The fluid-infector of claim 1, wherein:

the pulse-generator includes structure that is so configured as to enable adjustment of the frequency at which pulses pass through the outlet-port, and includes also;

(a) an operable pulse-amplitude-adjuster, which is effective, when operated, to change the amplitude of the pulses;

(b) an operable pulse-rise-time-adjuster, which is effective, when operated, to change the rise-time of the pulses; and

(c) an operable differential-pressure adjuster, which is effective, when operated, to change the difference between the pressure in the upstream-chamber and the pressure in the downstream-chamber that obtains when the pulse-port is fully closed.

17. The fluid-infector of claim 1, wherein:

groundwater in the body of ground is contaminated with a toxic liquid;

the toxic liquid is amenable to alleviation of its toxicity as by being mixed with a remediation liquid; and

the injected fluid is the remediation liquid.

18. Procedure for using the fluid-infector of claim 16 to inject a fluid into the ground, including:

providing a reservoir of the fluid to be injected;

providing an injection pump, and operating the same to inject the fluid from the reservoir, through the pulse-generator, via the injection-well, down into the ground;

monitoring pressure in the downstream-chamber, and at least after a substantial pressure obtains in the downstream-chamber, operating the electric motor, thereby creating pulses in the fluid being injected;

monitoring pressure in the upstream-chamber and monitoring flowrate of fluid passing into the ground; and

adjusting pulse frequency, pulse-amplitude, pulse-rise-time, and differential-pressure, in such manner as to maximise the amount of fluid delivered into the ground over a period of time.