US3325222A

US3325222A - Method and apparatus for pumping mixtures of liquids and large solid bodies

Info

Publication number: US3325222A
Application number: US523197A
Authority: US
Inventors: George F Round; Kruyer Jan
Original assignee: Alberta Research Council
Current assignee: Alberta Research Council
Priority date: 1966-01-26
Filing date: 1966-01-26
Publication date: 1967-06-13
Anticipated expiration: 1984-06-13

Description

June 1957 s. F. ROUND ETAL METHOD AND APPARATUS FOR PUMPING MIXTURES OF LIQUIDS AND LARGE SOLID BODIES 5 Sheets-Sheet 1 Filed Jan. 26, 1966 June 13, 1967 METHOD AND APPARATUS FOR PUMPING MIXTURES OF LIQUIDS AND LARGE SOLID BODIES Filed Jan. 26, 1966 5 Sheets-Sheet 2 F. ROUND ETAL 3,325,222

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METHOD AND APPARATUS FOR PUMPING MIXTURES OF LIQUIDS AND LARGE SOLID BODIES Filed Jan. 26, 1966 5 Sheets-Sheet 5 so ac 100 W I, Wafer inpui. /min.

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United States Patent METli-IUD AND APPARATUS FOR PUMPING MIXTURES 0F LIQUlDd AND LARGE SOLID BQDIES George F. Round and Jan Kruyer, Edmonton, Alberta,

Canada, assignors, by mesne assignments, to the Research Council of Alberta, Edmonton, Alberta, Canada, a body corporate Filed Jan. 26, 1966. Ser. No. 523,197 3 Claims. (Cl. 302-14) ABSTRACT (IF THE DISCLGfiURE A manner of imparting energy to a liquid stream carrying solid objects in a pipeline wherein liquid is withdrawn from the stream at one location and injected under pressure in the form of jets into the stream at another location upstream of the first location; each jet has a peripheral velocity component with respect to the stream and a direction of flow substantially the same a that of the stream whereby a swirling motion is imparted to the stream to stabilize the objects being carried therein.

The pipeline transmission in a liquid carrier of relatively large solid objects, that is, objects of generally cylindrical or spherical form having a diameter at least as great as half the internal pipeline diameter, requires energy which must be derived from the carried liquid. The conventional manner of imparting energy to a liquid flowing in a pipeline is by means of a centrifugal or positive displacement type pump. These pumps, while they do permit passage through them of liquids and slurries of liquids and particles of relatively small dimensions, do not permit the direct transmission of large objects.

It is an object of thi invention to provide a method and device for imparting energy to a flowing liquid stream carrying solid objects in a pipeline while permitting such objects to pass through such device.

The invention resides in a method of imparting energy to a liquid stream carrying solid objects in a pipeline which comprises withdrawing liquid from said stream at one location, and injecting under pressure a plurality of jets of said withdrawn liquid into said stream at another location upstream of said first location.

The invention also resides in a device for imparting energy to a liquid stream carrying solid objects in a pipeline which comprises a tank surrounding a section of said pipeline, a plurality of liquid injection tubes each extending into said pipeline section, said pipeline section having a plurality of liquid discharge opening downstream of said tubes and communicating with said tank, said tank having a liquid outlet leading therefrom.

The invention will be described with reference to the accompany drawings, in which FIGURE 1 is a side elevation, partly in section, of a device in accordance with the invention,

FIGURE 2 is an end elevation.

FIGURE 3 is a plot of the results of an object velocity test in an example of the method of the invention, and

FIGURES 4, 5 and 6 are plots of results obtained in the operation of a device in accordance with the invention.

Referring to FIGURES 1 and 2 of the drawing, 10 is a pipeline for transportation of objects, such as the spherical object indicated at 11, in a flowing carrier stream liquid.

A tank 12 surrounds a section 13 of the pipeline which extends through end walls 14 of the tank.

A plurality (two as shown) of tubes 15 extend into the pipeline section 13, each said tube extending through a wall of the tank and having an outlet 16 in the pipeline.

3,325,222 Patented June 13, 1967 The outlets 16 are, as shown, diametrically opposed to each other.

A pump 17 has its outlet connected to the tubes 15 and its suction side connected to a liquid discharge outlet 18 in the tank. Liquid discharge from the pipeline into the tank is provided by means of a plurality of holes 19 in the pipeline section 13 located downstream of the jet outlets 16.

Each tube 15 has a tangential relation to the pipeline section 13 but its axis has an angular relation to the pipeline axis (see FIGURE 2) whereby the radial angle of injection through outlet 16 with the pipeline axis is approximately zero. The tangential angle is not of critical importance and may be 15 to 45.

In operation, liquid entering the pipeline section 13 is withdrawn from section 13 via discharge holes 19 and reinjected into the pipeline section in the form of high energy jets through outlets 16, by means of pump 17. Some of this injected liquid will leave the device through holes 19 and is reinjected. This latter portion or internal circulation of liquid is desirable only to a minor extent, that is, not substantially more than 20% 0f the reinjected liquid.

The direction of flow of the jets is substantially the same as that of the main stream to impart momentum thereto. Each jet ha two velocity components, one axial and one peripheral. The relative magnitude of these components depends upon the size of the angle of jet relative to the axis of the pipeline. Ideally, and as previously indicated, there is substantially no radial velocity component since such a component in this type of device could only result in wasted energy due to turbulence created by the interaction and mixing of the high speed jets. In practice, a small radial component exists since the injection tubes have a finite radial angle. The centrifugal action on the liquid of the peripheral component opposes this radial action. In this specification and claims, this finite radial angle is regarded as within the scope of the expression the radial angle of injection with the pipeline axis is substantially zero, or the equivalent thereof.

Since there is a peripheral component, a swirling motion is imparted to the main liquid stream. The purpose of this swirling motion is twofold: firstly, to create a pressure distribution across the radius of the pipeline such that pressure increases outwardly and reaches a maximum at the inner wall surface of the pipeline, and secondly, to cause the solid object being transported to spin about its longitudinal axis and thus stabilize itself for smoother passage through the device. Generally speaking, the solid object will have the shape of a sphere or a cylinder to facilitate such spinning action.

A device is accordance with the invention has been subjected to a number of experimental tests.

In one such test, the exit holes 18 were located at different distances downstream from the jet outlets 16. FIG- URE 3 is a plot of the velocity attained by a inch diameter polyethylene sphere in a one inch internal diameter pipeline as a function of the distance between the injection points 16 and the exit holes 18 for various values of W the mass fiow rate of injected liquid in pounds per minute. The density ratio of the sphere to the carrier liquid (water) was 0.92. The tangential angle of injection and diameters of injection tubes were maintained constant at 15 and inch, respectively, throughout these tests. It will be observed that the velocity attained by the sphere approaches asymptotically a particular value as the distance between injection and discharge increases, regardless of the liquid injection rate W In some tests, the discharge holes were located opposite the injection jets and slightly upstream from them. In each case, although the efliciency may be said to be increased, the device prevented the sphere from passing. In effect, to have passed through the device, the sphere would have had to have travelled from a region of low to a region of high pressure.

The test results illustrated in FIGURES 4, and 6 a were obtained with the device set at a fixed injectiondischarge distance of 1 inches.

FIGURE 4 is a plot of the amount of internal circulation of liquid, that is, lost energy as a function of the rate of liquid input W at three different tangential injection tube angles, and 45. W as indicated in FIGURE 1, is the mass flow rate in pounds of liquid flowing per minute in the pipeline after passing the holes 18. It will be observed from FIGURE 4 that the amount of internal circulation intially falls off rapidly with increasing rate of liquid input W In addition, as the injection angle is decreased the amount of liquid internally circulating decreases.

FIGURE 5 shows the same functions as FIGURE 4, except that the tangential angle of injection was fixed at 15 and the diameter of the tubes was varied from 0.25

inch to 0.5 inch. There is a decrease of internal circulation with increase in rate of water injection and decrease of diameter of injection tube.

FIGURE 6 is a plot of percentage efficiency of total energy of the system as a function of W It is complimentary to FIGURE 5 in that as the amount of internal circulation decreases the total energy efiiciency of the system would be expected to rise. The plot of FIGURE 6 is based on the following formula,

where In the tests, the longitudinal distances between the pressure points were P to P 12%"; P to P 1"; P to P 18 /2. It can be seen that, in the tests conducted, the most favourable configuration at the maximum flow rate of 140 lbs/min. gives a total energy efficiency of 16%.

Such an efficiency, while acceptable, is subject to considerable improvement.

We claim:

1. A method of imparting energy to a liquid stream carrying solid objects in a pipeline which comprises withdrawing liquid from said stream at one location only in the form of a plurality of circumferentially spaced outlets and injecting under pressure a plurality of jets of said withdrawn liquid into said stream at another location spaced upstream of said first location, each of said jets having a peripheral velocity component with respect to said stream and a direction of flow substantially the same as that of said stream and having substantially no radial velocity component whereby a swirling motion is imparted to said stream.

2. A device for imparting energy to a liquid stream carrying solid objects in a pipeline which comprises a plurality of liquid injection tubes each having an outlet in said pipeline, each said tube having an axis in tangential relation to said pipeline and in angular relation to the axis of said pipeline, each said tube having a radial angle of injection with said pipeline axis of approximately zero, a tank surrounding a section of said pipeline, said pipeline section having a plurality of circumferentially spaced liquid discharge openings downstream of said tube outlets and communicating with said tank, said tank having a liquid outlet leading therefrom and being otherwise imperf orate, and a pump having a suction side connected to said tank outlet and an outlet connected to said tubes.

3. A device for imparting energy to a liquid stream carrying solid objects in a pipeline which comprises a tank surrounding a section of said pipeline, a plurality of liquid injection tubes each having an outlet in said pipeline section, each said tube having an axis in tangential relation to said pipeline and in angular relation to the axis of said pipeline and a radial angle of injection with said pipeline axis of approximately zero, said pipeline section having a plurality of circumferentially spaced liquid discharge openings downstream of said tube outlets and communicating with said tank, said tank having a liquid outlet leading therefrom and being otherwise imperforate, and a pump having a suction side connected to said tank outlet and an outlet connected to said tubes.

References Cited 7 UNITED STATES PATENTS 7 2,811,393 10/1957 Little 30214 3,038,760 6/1962 Crooke 302-14 3,205,016 9/1965 Panning 302-23 ANDRES H. NIELSEN, Primary Examiner.