US3816027A - Eductor jet pump and method - Google Patents

Abstract

An eductor jet pump including a venturi throat mounted at the input end of a discharge line into which a high velocity fluid jet nozzle is directed. Hydraulic cylinders and a hydraulic control circuit provide for relative movement of the jet nozzle toward or away from the venturi throat for either pulsating operation by regular cycling of the nozzle portion, for specific control of efficiency by nozzle position, or for closing the venturi throat to prevent backflow.

Description

O United States Patent 11 1 1111 3,816,027 Miscovich [451 Jun 11, 1974 [54] EDUCTOR JET PUMP AND METHOD 1,133,601 3 1915 Wood 417/183 1,671,564 5/1928 Andrews.. 417/184 X [75] Inventor: mm Orange Cahf- 2,608,157 11/1952 Conery 417/82 73 Assignee; Marcona Corporation, San 2,933,105 4/1960 Jer1nan.... 91/216 B Francisco Calif 3,043,107 7/1962 Ma aus 417/184 x 3,093,088 6/1963 Ventress.. 417/54 [22] Filed: Sept. 20, 1973 ,472,026 10/1969 Conabee.. 91/462 X [2]] App] NO 398 981 3,598,504 8/1971 Siravo 417/184 R l t d Us, A li ti D t Primary Examiner-Carlton R. Croyle [63] Continuation of $61. No. 181,017, Sept. 16, 1971, ExammerRlchard Gluck abandoned.

[57] ABSTRACT [52] US. Cl 417/184, 417/191, 302/15 n or jet pump including a venturi throat [51] Int. Cl F04f 5/48, 865g 53/30 m unted a h input end of a discharge line into [58] Field of Search 91/462, 218, 216 B; i h a high velocity flui jet nozzle is directed. Hy- 417/183, 184, 76, 82, 170, 191, 188; 302/57, draulic cylinders and a hydraulic control circuit pro- 15 vide for relative movement of the jet nozzle toward or away from the venturi throat for either pulsating oper- [56] References Cited ation by regular cycling of the nozzle portion, for spe- UNITED STATES PATENTS cific control of efficiency by nozzle position, or for H7 808 8 87 l Pangbam 91/218 closing the venturi throat to prevent backflow. 466:213 12/1891 6 Claims, 4 Drawing Figures Beard 417/183 I ELASTOMERIC 1 LINING EDUCTOR JET PUMP AND METHOD This is a continuation, of application Ser. No. 181,017 filed Sept. 16, 1971, now abandoned.

This invention relates to eductor jet pumps and to methods of their operation in which a high velocity fluid is passed through a venturi throat to create a lifting force for material in the vicinity of the throat opening. In one particular application, the eductor jet pump finds use in the dewatering of settled slurries over a wide range of elevations such as is encountered in the progressive loading and dewatering of supernatant liquids from settled mineral ore slurries aboard ships. The following particular description will be set forth in connection with such slurry dewatering. However, it should be understood that the eductor jet pump of the present invention will find many other uses, including that of a variable metering device, or a solids or slurry pump and the like.

In the loading of pulpable slurries of mineral ores aboard ships or into other vessels, it is required that the suspending liquid be progressively eliminated before or in the course of transporting such material from the point of loading to destination. As the liquid is removed from the freshly loaded material, its volume may be restored by additional slurry and liquid, a compact economically transportable mass is obtained which is not free flowing so that vessel stability is obtained.

The present invention finds particular use in the ship loading of ore or mineral solids in slurrified form in which the iron ore is of a magnetic type which has been crushed, milled and beneficated to produce discrete particulate solids, the bulk of which may have a size ranging down from 100 mesh. The dry specific gravity of the ore may be of the order of 4.5 and the settling rate in water as a suspending liquid is relatively high. Typically, such ore solids are pulped with water to form pumpable slurries which contain at least 60 percent and up to 80 percent solids. The present eductor jet pump permits the elimination or removal of supernatant water from such settled slurries after they have been loaded into holds.

Heretofore, eductor jet pumps have been used for removing such supernatant liquids but they have not been entirely satisfactory due to the high pumping heads that are often required when pumping from deep within the holds and the change in head which results from the change in level of supernatant water during successive cycles of loading. That is to say, initially dewatering takes place from deeper portions within the hold of the ship, while at later stages of loading, the pump operates at more elevated positions. Present pumps do not account for the change in efficiency due to this change in the pumping head. Furthermore, when pumping against a high head from deep within a vessel, the pump is subject to back flooding of the entire head standing in the discharge line when the same is turned off. Such flooding can result in substantial inefficiencies since a considerable volume of water is relaesed back into the freshly dewatered slurry. There is, therefore, a need for a new and improved eductor jet pump for use in the removal of supernatant liquids from settled slurries.

In general, it is an object of the present invention to provide an eductor jet pump and method which will overcome the limitations and disadvantages by the foregoing use of a variable relationship between throat and a high velocity fluit jet.

Another object is to provide an eductor jet pump and method of the above character which facilitates the eliminating of settled supernatant liquid from previously suspended slurries.

Another object of the invention is to provide an eductor jet pump and method of the above character which will facilitate cyclic loading and dewatering of ore slurries to insure solidified non-shifting cargo during transit.

Another object of the invention is to provide an eductor jet of the above character in which the venturi throat cross section is variable during operation and which can be shut off completely to prevent back flow.

Another object of the invention is to provide an eductor jet pump and method of the above character in which the efficiency is variable and may be adjusted to suit the operation at various elevations.

Another object of the invention is to provide an eductor jet pump and method of the above character in which venturi throat cross section is varied regularly over a given cycle interval to provide pulsating operation.

The eductor jet pump and method of the present invention are particularly suitable for the dewatering of settled slurries in ships holds and includes a discharge line terminating at its outer end in a jet nozzle which is directed into the throat. The nozzle is mounted for reciprocal movement towards and away from the throat to allow metering of the intake flow or to permit closure with the nozzle to shut the section flow off entirely. A hydraulic circuit is provided through the action of suitable cylinders to control the position of the jet with respect to the throat. Such position may be adjusted to a fixed position to control metering of flow through the throat or may be set for cyclic operation in which the jet is moved toward and away from the throat through a given number of strokes per minute to thereby provide pulsating operation. These and other objects and features of the invention will become apparent from the following description and claims when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view partially broken away of an eductor jet pump constructed in accordance with the present invention, the hydraulic control circuit of which is shown schematically.

FIG. 2 is a cross-sectional view taken along the lines 22 of FIG. 1.

FIG. 3 is a cross-sectional view taken along the lines 33 of FIG. 1.

FIG. 4 is a top plan view partially broken away of another embodiment of an eductor jet pump constructed in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description will be given in connection with the installation of an eductor jet pump and its use aboard ship, particularly for the dewatering of supernatant liquid from settled slurries. Typically, mineral slurries of this type settle rapidly and into a lower zone wherein the solids are in direct physical contact overlaid with the zone in which the solids are still in the process of settling and the third or upper zone which is essentially quiescent and clarified liquid from which the solids are removed. Eventually a wall defined plane of demarcation develops between the settling and settled zones and the upper zone of essentially clear liquid. The present invention contemplates removing of the suspending liquid by lowering the eductor jet pump of the present invention into the clarified supernatant liquid and pumping the same off, after which additional slurry may be pumped in and progressively dewatered in the same manner.

Accordingly, referring to FIGS. 1 through 3 there is shown an eductor jet pump of the present invention which includes a discharge line mounted on the suitable support structure such as bulkhead (not shown). The discharge line is of relatively large diameter and is connected by a swivel union (not shown) to a discharge conduit leading overboard. The other end of the discharge line may be supported by a hoisting davit provided on the upper deck having a block and line connected to a pad eye at the outer end of the discharge line. The lower end of the discharge line terminates in means forming a venturi throat 12 which preferably is bell-shaped in a continuous annular curve.

A high velocity input line 14 is provided for supplying fluid, such as a liquid, and includes a jet nozzle 16 at its lower end directed coaxially into the venturi throat in an operating position proximate thereto. Suitable means are provided for supporting the input line in substantially parallel relation to the discharge line and for moving the lower portion thereof so that the nozzle 16 can be brought towards and away from the venturi throat 12. Such means takes the form of a series of yokes 18, 20 rigidly attached to the discharge line and carrying bushed guides 22, 24 thereon for receiving the moveable portion 25 of the input line. An additional yoke 26 is attached to the input line at a position such that an extension thereof in the form of a guide shoe 27 rides on the discharge pipe immediately above the venturi nozzle to aid in preventing gross rotation of the members about each other. The lower end of the input line is U-shaped so that the nozzle 16 is directed in coaxial relationship toward the venturi throat. As shown in FIGS. 1 and 3, a plurality of straightening vanes 29 are mounted to extend radially from the input line walls to aid in reducing vortex formation and resulting turbulence and thereby increase the efficiency of the jet.

A resilient lining 28 is provided on the interior walls of the venturi throat. Preferably such lining is elastomeric and may be constructed of a suitable rubber-like formulation such as one of the urethane rubbers. The exterior of the nozzle is so sized that with respect to the throat, that when the nozzle is brought up into the throat, sealing contact is made with the elastomeric lining to thereby close the throat as a check valve to seal the same against backwash in the reverse direction down the discharg line.

Actuator means are provided at the upper end of the input line for varying and controlling the position of the nozzle either at some selected location or for reciprocating the same during the operation of the eductor. Such means takes the form of a bell 30 mounted at the upper end of the input line section 25 and forming a cylinder. The portion 25 of the input line between the bell and nozzle is thus moveable being supported for reciprocating motion in guides 22, 24. A fixed portion 32 of input line 14 is supported on discharge line 10 by a suitable double yoke support 34 and extends downwardly into the cylinder formed by the bell. The bell is provided with a pair of spaced seals 36, 38 which engage the side wall of the downwardly extending fixed portion of input line. The input line carries a fixed position piston 40 which together with the bell defines a volume of a double acting cylinder together with the seals 36, 38. The ends of the cylinder are provided with hydraulic inlets 42, 44 so that the cylinder and the associated lower end of the discharge of the input line may be given up or down by application of hydraulic pressure difference on an appropriate side of the piston 40.

able portion 25 of the input line and the associated noz zle and consists of a parallel circuit including in one branch a four-way hydraulic valve 45 having opera tional outputs 46, 48 connected to the inlets 42, 44 on each side of the cylinder and a drain or relief line 49 passed through a metering valve 50 which partially controls the speed of movement of the apparatus. Screw adjustable limit stops 52, 54 are carried on the cylinder and actuate a level control 61a on an auto valve 51 forming the other branch of the circuit, and indicate the desired extremes of limited travel of the cylinder up or down, as indicated by the dotted outline 59 showing the uppermost or closed position. The stops serve to operate the auto valve and thereby reverse the pressure distribution and the direction of travel of the moveable input line at each extreme. Fluid pressure to the auto valve is supplied through a takeoff line and a main shut-off valve 60 from the high pressure input line Means are provided for sensing the nature of the material flowing in the discharge line and for overriding the hydraulic control circuits to thereby close the venturi throat on the occurrence of certain predetermined conditions. Such means consists of suitable sensors 61, 62 mounted on the discharge line. Sensor 61 is responsive to flow in the discharge line and operates upon cessation of the flow to energize the solenoid 68 on valve 45 to close the throat and prevent backwash. Sensor 62 senses solids content, as in the case of magnetic iron ore by measuring changes in the magnetic field. When the ore solids content becomes too great, sensor 62 energizes the second solenoid 64 on valve 45 to close the nozzle in the throat. When the discharge line is closed completely, high pressure water is the only element introduced into the discharge line and acts to force any obstruction of high solids load out.

Together, the actuator means and the control circuit serve to permit continuous control of the nozzle throat opening during the operation of the eductor.

Thus, the present invention provides considerable flexibility in operation by permitting most efficient use at variable levels by moving the relative position of the nozzle to the throat to control the amount of throat opening. When pumping maximum depths the throat nozzle opening is narrowed to restrict the amount of material taken in and thereby develop a higher pumping head. In cyclic loading operations in which slurries are successively loaded and dewatered, the eductor is higher at the end of the loading cycle and the pumping head reduced. At that time the throat can be opened up to take up the maximum volume. When the nozzle is in completely closed position, it compresses against the rubber lining 28 of the throat and makes a completely tight seal. By using such a lining it is also possible to reduce the possibility of a rock holding the nozzle in partially opened position. Of course, at the end of each loading cycle, the throat is closed and the eductor moved up out of the way from the receiving vessel so that additional slurry can be pumped in. Thus, the adjustable feature of the present eductor allows use of maximum efficiency of the venturi throat opening which corresponds to various elevations and the volume of liquid decreases as the nozzle closes the throat area. And, the eductor lift does not stall as it would if the nozzle were used in a fixed single position. Additionally, by shutting off the eductor, backflooding of the standing head in the discharge line back is completely prevented.

In addition to the using of the adjustable throat feature, the present invention can also be operated in a reciprocating mode in which the nozzle is moved toward and away from the throat over a predetermined distance and during a predetermined cycle time to vary the rate in amount of eduction for supply to the liquid charge being educted. In that mode of operation, the adjustable limit stops 52, 56 on the moveable portion 14 of the intake line serve to drive the operating lever 51a on the auto valve 51. By adjusting metering valve 50, the rate of movement of the intake line may be adjusted to determine the number of cyles per minute which are used. Generally, repeat time in the range of about 1 to 5 seconds for each complete cycle is found satisfactory. When so arranged, the jet automatically reciprocates and in each cycle gulps in a load of liquid which then moves up the throat and is pushed out of the discharge line. Meanwhile the eductor retracts to pick up another load and proceeds continually to discharge the liquid in a series of pulsations. Such operation is expected to be most useful in pumping slurries with the present eductor.

Referring now to FIG. 4, there is shown an alternative embodiment of the invention utilizing a pair of double acting cylinders 80, 82 mounted on each side of the fixed portion 84 of the input high pressure line and having actuating arms 86, 88 extending downwardly to connect to a suitable flange 90 carried on the moveable portion 92 of the input line which is sealed to the fixed portion for sliding movement by suitable single packing 94. This arrangement facilitates construction of the present invention utilizing conventionally available components.

An additional feature illustrated in FIG. 4 concerns the lateral position control of the nozzle. At the lower end of the bell 12 forming the venturi. throat there is provided an outwardly extending annular rim 96 having guide holes therein. The end of the input line immediately beneath the nozzle is provided with an annular flange 98 carrying guide rods 99, 100 mounted in alignment with the guide holes in the rim 96 and in alignment with the desired movement of the nozzle toward the venturi. In this way, forces subjected to the eductor during its operation will be unable to carry the nozzle too far out of misalignment and thereby either hinder its ability to seat into closure if desired or impair its efficiency by lateral mispositioning. The foregoing embodiments illustrate operation in which the throatnozzle relationship is determined by movement of the nozzle and portions of the associated fluid supply. It is obvious that the discharge line could, alternatively, be constructed to move relative to a fixed nozzle by interchanging certain parts between the respective lines. Accordingly, any procedure for rapidly adjusting the relative positions of the throat and nozzle should be comprehended within the scope of the present invention.

While there has been disclosed herein certain specific embodiments in order to illustrate the carrying out of the present invention, it should be understood that they are to be taken in the illustrative sense, as many changes and adaptations of the present invention will occur to those skilled in the art to which it pertains. For example, while there has been shown the use of a hydraulic system for controlling the inlet line 14 position driven from the high pressure line supply itself, a separate hydraulic circuit could be used and even operate on a different media such as oil. In fact, it even is possible to use mechanical actuators with some loss in ease of operation. Many other applications of the invention besides dewatering of slurries will suggest themselves to those skilled in the art. For example, the eductor jet pump of the present invention should find direct application as a proportioning device in which an additive is to be mixed with a slurry or liquid as in fire fighting applications. Also, the use of air, air-liquid mixtures, or other gas and gas-liquid mixtures could be used in the high pressure jet supply where the additional buoyancy created was required to obtain satisfactory lift. Accordingly, the invention should be construed broadly, and should only be limited by the scope of the appended claims.

I claim:

1. Eductor jet pump apparatus for removing liquids or liquid suspended material from a pool thereof, comprising a discharge line having one open end thereof adapted to be lowered into said pool, bell means forming a venturi throat at said one end of the discharge line and defining an inlet opening at the lower end thereof for receiving material directly from said pool, a highvelocity liquid input line having upper and lower portions, said upper portion having one end thereof adapted to be connected to a source of liquid under pressure, means forming an upwardly directed jet nozzle at the end of the lower portion of said input line, guide means for carrying said input line in parallel alignment alongside said discharge line said guide means serving to align the nozzle in operating position proximate the end of said discharge line and directed into said venturi throat, said guide means being constructed and arranged to permit said lower portion and said jet nozzle to move in opposite directions towards and away from said throat and in axial alignment therewith to thereby vary the effective area of said inlet opening exposed to said pool, means interconnecting said upper and lower portions for movement relative to each other and forming a seal therebetween, hydraulic actuator means mechanically connected between said upper and lower portions of said high-velocity input line for positively moving said lower portion and said jet nozzle relative to said throat during operation of the jet pump to thereby regulate the efficiency of said eductor, and means for controlling said hydraulic actuator means so that the relative position of said nozzle and throat is selectively maintained in accordance with the setting of the control means.

2. An eductor jet pump as in claim 1, in which said venturi throat is provided with an elastomeric lining to provide a closure seat for said jet nozzle, and in which the outer configuration of said jet-nozzle is adapted to engage said elastomeric lining to form a seal.

3. An eductor jet pump as in claim 1, in which said hydraulic actuator means for moving said jet nozzle includes a double-acting hydraulic cylinder, and a fourway auto valve having operational outputs connected to each side of said cylinder, said auto valve including sensing means for determining the limits of travel of said hydraulic cylinder means to thereby reverse its direction of motion at each limit of travel.

4. An eductor jet pump, as in claim 1, in which said actuator means include means for repeatedly cycling said nozzle between a partially opened and more fully opened positions.

5. An eductor jet pump apparatus for removing liquids or other material from a pool thereof, a discharge line having an open end thereof adapted to be lowered into said pool, bell means forming a venturi throat at said end of said discharge line defining an inlet opening at the lower end thereof, a high-velocity fluid input line, including an upwardly directed jet nozzle formed at a remote end thereof, means mounting said highvelocity fluid input line relative to said discharge line such that said jet nozzle is aligned in an operating position proximate and directed into said venturi throat, means for moving said jet nozzle relative to said throat for varying the position of said jet nozzle with respect to said throat and thereby the effective area of said inlet opening exposed to said pool for regulating the efficiency of said eductor, at least one guide rod, means for supporting said guide rod on one of said venturi throat bell and jet nozzle, and means carried on the other of said throat and jet venturi nozzle for slidably guiding said guide rod to prevent lateral motion thereof as the venturi throat and jet nozzle are relatively moved toward and away from each other.

6. Eductor jet pump apparatus for removing liquids or other materials from a pool thereof, comprising a discharge line having an open end thereof adapted to be lowered into said pool, bell means forming a venturi throat at said lower open end of said discharge line and defining an inlet opening exposed to said pool, a liquid input line having an upper portion adapted to be connected to a source of liquid under pressure and a lower portion mounted for movement relative to said discharge line, an upwardly directed jet nozzle formed at the lower end of said lower portion, means carrying said liquid input line such that the said jet nozzle is aligned in an operating position proximate and directed to said venturi throat, means for moving said jet nozzle and throat relative to each other during operation of the same for varying the position of said jet nozzle with respect to said throat and thereby varying the effective area of said inlet opening for regulating the efficiency of said eductor jet pump, said means for moving said jet nozzle including a double-acting hydraulic actuator concentrically disposed about a movable portion of said high-velocity liquid input line, said actuator being connected between the movable portion and a fixed portion of said liquid input line said actuator including a piston carried on one of said portions of said input line.

Claims (6)

1. Eductor jet pump apparatus for removing liquids or liquid suspended material from a pool thereof, comprising a discharge line having one open end thereof adapted to be lowered into said pool, bell means forming a venturi throat at said one end of the discharge line and defining an inlet opening at the lower end thereof for receiving material directly from said pool, a highvelocity liquid input line having upper and lower portions, said upper portion having one end thereof adapted to be connected to a source of liquid under pressure, means forming an upwardly directed jet nozzle at the end of the lower portion of said input line, guide means for carrying said input line in parallel alignment alongside said discharge line said guide means serving to align the nozzle in operating position proximate the end of said discharge line and directed into said venturi throat, said guide means being constructed and arranged to permit said lower portion and said jet nozzle to move in opposite directions towards and away from said throat and in axial alignment therewith to thereby vary the effective area of said inlet opening exposed to said pool, means interconnecting said upper and lower portions for movement relative to each other and forming a seal therebetween, hydraulic actuator means mechanically connected between said upper and lower portions of said high-velocity input line for positively moving said lower portion and said jet nozzle relative to said throat during operation of the jet pump to thereby regulate the efficiency of said eductor, and means for controlling said hydraulic actuator means so that the relative position of said nozzle and throat is selectively maintained in accordance with the setting of the control means.

2. An eductor jet pump as in claim 1, in which said venturi throat is provided with an elastomeric lining to provide a closure seat for said jet nozzle, and in which the outer configuration of said jet nozzle is adapted to engage said elastomeric lining to form a seal.

3. An eductor jet pump as in claim 1, in which said hydraulic actuator means for moving said jet nozzle includes a double-acting hydraulic cylinder, and a four-way auto valve having operational outputs connected to each side of said cylinder, said auto valve including sensing means for determining the limits of travel of said hydraulic cylinder means to thereby reverse its direction of motion at each limit of travel.

4. An eductor jet pump, as in claim 1, in which said actuator means include means for repeatedly cycling said nozzle between a partially opened and more fully opened positions.

5. An eductor jet pump apparatus for removing liquids or other material from a pool thereof, a discharge line having an open end thereof adapted to be lowered into said pool, bell means forming a venturi throat at said end of said discharge line defining an inlet opening at the lower end thereof, a high-velocity fluid input line, including an upwardly directed jet nozzle formed at a remote end thereof, means mounting said high-velocity fluid input line relative to said discharge line such that said jet nozzle is aligned in an operating position proximate and directed into said venturi throat, means for moving said jet nozzle relative to said throat for varying the position of said jet nozzle with respect to said throat and thereby the effective area of said inlet opening exposed to said pool for regulating the efficiency of said eductor, at least one guide rod, means for supporting said guide rod on one of said venturi throat bell and jet nozzle, and means carried on the other of said throat and jet venturi nozzle for slidably guiding said guide rod to prevent lateral motion thereof as the venturi throat and jet nozzle are relatively moved toward and away from each other.

6. Eductor jet pump apparatus for removing liquids or other materials from a pool thereof, comprising a discharge line havIng an open end thereof adapted to be lowered into said pool, bell means forming a venturi throat at said lower open end of said discharge line and defining an inlet opening exposed to said pool, a liquid input line having an upper portion adapted to be connected to a source of liquid under pressure and a lower portion mounted for movement relative to said discharge line, an upwardly directed jet nozzle formed at the lower end of said lower portion, means carrying said liquid input line such that the said jet nozzle is aligned in an operating position proximate and directed to said venturi throat, means for moving said jet nozzle and throat relative to each other during operation of the same for varying the position of said jet nozzle with respect to said throat and thereby varying the effective area of said inlet opening for regulating the efficiency of said eductor jet pump, said means for moving said jet nozzle including a double-acting hydraulic actuator concentrically disposed about a movable portion of said high-velocity liquid input line, said actuator being connected between the movable portion and a fixed portion of said liquid input line said actuator including a piston carried on one of said portions of said input line.

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