US3257150A - Arrangement for conveying solids in a stream of fluid - Google Patents

Description

June 21, 1966 T. B. WALSH 3,257,150

ARRANGEMENT FOR CONVEYING SOLIDS IN A STREAM OF FLUID Filed May 21, 1964 2 Sheets-Sheet 1 l I E [0 lpl 3 I I U V I!) In I 0| 1 I0 i,,} o

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THOMAS B. WAL 5H A T TO/PNE V June 21, 1966 T. B. WALSH 3,257,150

ARRANGEMENT FOR CONVEYING SOLIDS IN A STREAM 0F FLUID Filed May 21, 1964 2 Sheets-Sheet 2 FIG- 3 FIG 4 EVV INVENTOR. THOMAS B. WALSH BY WM.

ATTOPNEV United States Patent This application is a continuation in part of application No. 252,719 filed January 21, l963,'and now abandoned. The present invention relates to solid materials such as gravel, coke, catalysts, grain, copra and the like which may be conveyed by entraining them in a stream of gaseous or liquid fluid. Such a stream is produced by vacuum, or sucking the fluid at substantial'speeds through tubular conduits with the aid of pumps or blowers; and at the intended place of deposit, the speed of the stream is reduced by interposing a container of increased crosssectional area into the conduit so that the fluid loses its ability to carry the solids and the solids settle on the floor of the container. In arrangements of this kind it has usually been necessary to shut down operation whenever the container providedfor the collection of the conveyed material became filled to capacity, so that the container might be emptied and/ or a new container be moved into its'place. Such shut-downs in the operation of the apparatus are undesirable because they mean a loss of time in which neither the equipment nor some of the attending personnel are fully employed. Further, in the transport of heavy material such as here disclosed, if the system stops for any reason it cannot be restarted without cleaning out the entire conveying line. Thus, in the case of suction conveyors, it is necessary to keep a careful check upon the condition of the sedimentation container so that operation of the arrangement may be transferred to another container before the operating container is fully filled as otherwise some of the entrained solids might reach and damage the impellers of the pump or blower, or cause a shut-down of the system.

It is an object of my invention to provide an arrangement for conveying solids by a stream of fluid to a desired place, which may be operated uninterruptedly and without change in the line negative pressure.

'More specifically, it is an object of my invention to provide a conveying arrangement, of the type referred to, wherein the solids may be removed from the place of sedimentation without interrupting operation of the conveying process or employing vacuum-maintaining discharge valves.

Yet another object of the invention is to provide a suction-type conveying arrangement of the type referred to, which may be operated continually without endangering the impellers of the pump or blower, or substantially reducing the line negative pressure.

An additional object is to provide a recovery unit for solids conveyed by streams of fluid, that is of compact construction so that it may readily be mounted upon a vehicle for movement to intended places of use.

Further objects are to provide a construction of maximum simplicity, economy and ease of assembly'and disassembly, also such further objects, advantages and capabilities as will fully appear and as are inherently possessed by the device and invention described herein.

The invention further resides in the combination, construction and arrangement of parts illustrated in the accompanying drawings, and while there is shown therein a preferred embodiment thereof, it is to be understood that the same is illustrative of the invention and that the invention is capable of modification and change and comprehends other details of construction without departing from the spirit thereof or the scope of the appended claims.

In the drawings:

FIGURE 1 is a schematic plan view of a conveyingarrangement embodying my invention;

FIGURE 2 is a section taken along line 22 of FIG= URE 1 viewed in the direction of the arrows associated with said line;

FIGURE 3 is a section taken along line 3-3 of FIG- URE 2 and viewed in the direction of the arrows associated with said line; and

FIGURE 4 is a section through one of the components of the arrangement of my invention, taken along line g 44 of FIGURE 2.

In accordance with my invention I provide two alternate paths for the solids-conveying stream of fluid produced by a pump or blower, each passing through a sedimentation tank or compartment of its own, and I provide control means for selectively passing the stream through one of said tanks while preventing its passage through the other. In this manner it is possible to empty, or otherwise recondition, a filled sedimentation tank while the conveying process continues through the other, and to resume operation through the former tank once the latter has been filled and requires reconditioning. Thus, it is not necessary to interrupt the operation of the conveying arrangement of the invention when a sedimentation tank is filled to capacity, and in the case of conveying arrangements of the suction-type, there is no danger that solids entrained in the stream will reach and damage the impellers of the pump or blower since all fluid reaching the blower is filtered and the process is continued uninterruptedly by re-routi-ng the solids-carrying stream a safe time before the solids accumulating in one or the other sedimentation tanks have reached a dangerous level.

The arrangement of my invention comprises an elongated rectangular tank 10, that is divided into two adjacently located compartments 12a and 12b by a longitudinally extending center partition 14. At one end of said compartments a cross-wall 16 forms a chamber 18 that extends transversely across the tank 10 and with which both the compartments 12a and 12b communicate through apertures 20a and 20b respectively. Connected to the opposite ends of both said compartments by means of ,two branch pipes 26a and 26b with corresponding closure valves 27a and 27b and a common speed reduction chamber 24, is a conveyance conduit 22 provided with an intake nozzle 28 which may be of the fish-tail type as shown. Material from a heap of granular solids indicated at 30 may be drawn into the nozzle, and through conduit 22, chamber 24 and branch pipes 26a or 26b into the compartments 12a or 12b, as the case may be, by the action of a rotary blower 32 whose intake end is connected to the chamber 18 by a conduit 33. The apertures 20a and 20b are provided with a slide or other suitable valveindicated at 34 (see FIGURES 1 and 2) which is of such construction as to cover one of said apertures when it opens the other and vice versa, so that when one of said apertures is open, the other one is normally closed, except just prior to the re-routing to reduce the pressure in the unused tank. The valve 34 is so constructed that while one aperture. is open the other aperture may be opened slightly without substantial closing of the open aperture. Operation of the rotary blower 32, therefore, draws air and solids from the heap 30 through either compartment 12a or compartment 12b, depending upon the position of slide valve 34. The bottom of compartments 12a and 12b may be formed into hoppers 36a and 36b respectively (FIGURE 3), that are normally closed but which may be opened in-. dividually by manipulation of slide valves indicated at 38a and 38b in FIGURES 2 and 3. On the side of the compartments 12a and 12b, the openings 20a and 20b in cross-wall 16 may be covered by suitable filters 40a and 3 40b respectively, which may have the form of nylonwalled frames.

When it is desired to remove a heap of solids such as shown at 30 in FIGURE 1, the blower 32 is set into operation to establish and maintain a substantial negative pressure in the line to draw air and entrained solids into the nozzle 28 at substantial speeds. While operation at speeds which will pick up and entrain solids are con templated, it is to be understood that speeds which would cause damage or distintegration of the solids in any particular instances are not to be used. Speeds are to be consistent with the integrity of the products carried. Likewise, where a product may be damaged in the picking up, the product may be introduced into the stream in any other suitable manner. Within the conduit 22 the air stream carries the entrained solids to the chamber 24, and depending on whether the aperture a or the aperture 20b is open and the corresponding valve 27a or 27b, the air stream carries the solids along branch pipe 26a through open valve 27a, into compartment 12a, or along branch pipe 261) through open valve 27b, into compartment 12b. Since in either branch pipe a change of direction occurs in the advance of the air stream, it may be desirable to slow down to some degree the rapid advance of the entrained solids to reduce the wear on the walls of the branch pipes and/or to prevent disintegration of the conveyed solids at this point. For this reason interposition of chamber 24 between conduit 22 and the branch pipes 26a and 26b is advisable. In said chamber the speed of the air stream drops due to the greater lumen of said chamber as compared with conduit 22.

Since the necessary reduction in the speed of the air stream depends upon the nature of the solids entrained therein, i.e. their size, specific weight, shape, etc., it is preferable to employ a slow-down chamber whose lumen is adjustable. Such a chamber is shown in FIGURE 4. In said figure the side wall of the chamber is formed by an open shell 42 of flexible material, such as steel, whose longitudinal edge areas 44 and 46 overlap and may be fastened to each other in different positions of overlap by suitable screw means indicated at 48. Hence, when said edge areas overlap to a greater degree as shown in phantom lines in FIGURE 4, the lumen of the chamber is smaller and there will be a lesser reduction in the speed of the air stream passing therethrough. To provide an air tight seal between the overlapping edge areas 44 and 46 of shell 42, a rubber lining may be provided on the outer surface of the inner edge 44 as shown at 50 in FIGURE 4. Plates 51 and 52 of adequate size to form proper end walls for any condition of adjustment of chamber 24 may suitably be clamped to the shell 42.

In use, the blower 32 is set into motion with one of the apertures in cross-wall 16 open and the other closed. Let it be assumed that aperture 20a is open, valve 27a is open and that aperture 20b is closed and a substantial negative pressure has been established and is' maintained in the line. As a result thereof, air and solids are drawn into nozzle 28, travel along conduit 22 at considerable speed are slowed down in chamber :24 and pass through branch line 26a and valve 27a into compartment 12a. In compartment 12a the air stream slows down due to the large transverse width of the compartment as compared with the lumen of branch line 26a, to a degree where it is no longer capable of maintaining the solids in suspension, and in consequence thereof the solids drop and accumulate in the hopper 36a as shown in FIGURES 2 and 3. The air delivered to the compartment 12a is drawn through filter a and opening 20a into chamber 18, and from there through tube 33 into the suction end of the blower 32.

As soon as the solids deposited in compartment 12a reach a pre-determined level, and long before there is any danger that some of the solids might pass through the aperture 20a in the transverse wall 16, the valve 34 is actuated first partially to open aperture 20b in advance of any substantial closure of aperture 20a. Chamber 12!) prior thereto was at atmospheric pressure with valve 27b closed, aperture 2012 closed and dumping slide 38b closed. In order not to cause any substantial change in the line negative pressure, it is necessary to bring the chamber 12b to approximately the negative pressure of the line. Since common chamber 18 is always at the negative line pressure by the action of blower 32, the partial opening of the aperture 2% to the extent required will quickly bring about the uniformity of negative pressure. This is accomplished in a matter of seconds. It is to be understood that the common chamber 18 must be of sufficient size to enable the establishment of the operating negative pressure in the non-operating empty compartment 121; without the loss of any appreciable negative pressure in the operating compartment 12a. Thereupon the valve 201) is fully opened and the valve 20:: is simultaneously closed and also simultaneously the valve 27 b is opened and the valve 27a is closed. The air stream and solids drawn into the nozzle'28 and advancing along tube 22 will be delivered through branch conduit 26b and'valve 27b into compartment 12b, where the deceleration will cause the deposit of the solids into the hopper 36b. Owing to the closing of valves 27a and 20a, no part of the conveyed solids will now reach compartment 12a. The change-over from compartment 12a to 1212 is thus accomplished without any consequential change or drop in the negative line pressure, maintaining peak efficiency continuously. When the solids deposited in chamber 12b reach the pre-determined level, then the empty chamber 12a is returned to service by reversing the procedure.

After the valves 2% and 27b have been opened and the valves 20a and 27a have been closed, as stated above, the dumping slide 38a at the bottom of the loaded compartment 12a may be actuated to unload the contents of the compartment onto the ground or into a truck or railroad car or any other suitable receptacle that may be positioned underneath. This will result in compartment 12a being brought to atmospheric pressure, but due to the closure of aperture 20a and valve 27a the actuation of the slide 38a remains without adverse affect upon the negative pressure in the line and the intake of air and solids through the nozzle 28 and into compartment 12b. After dumping the slide 38a is closed. Although gravity unloading by dumping is shown, it is to be understood that any suitable method of unloading may be used including the use of positive pressures. The apparatus of the invention continues its performance at peak efficiency until compartment 12b is filled, whereupon the reconditioned compartment 12a will commence a new operation cycle by appropriate manipulation of the slide valve 34 while compartment 121) is cut out of operation and may be emptied. The change from one compartment to another isaccomplished without any appreciable reduction or diminution of the negative pressure or vacuum in the line and accomplishes continuous operation.

The apparatus illustrated in the accompanying drawings and described hereinbefore, does not only permit uninterrupted operation of the conveying process at peak efiiciency, it has the added advantage of constituting a recovery unit for the conveyed solids that is of extraordinary compactness so that it may readily be mounted upon motor driven vehicles and may thus easily be moved to any number of different places of use.

While I have described my invention as comprising a pair of adjacently positioned alternate settling compartments, it will be understood that it may comprise more than two such compartments of which one or some may be cut out of operation while the others collect the solids from the solids-conveying air stream produced by the blower 32 in conjunction with chamber 18. Also, while I have described my invention as employing a stream of gaseous fluid for conveying solids to a desired destination, it will be understood by those skilled in the art that the principles of my invention operate in the same manner when a liquid fluid, such as water, is employed for conveying appropriate solids.

The velocity to be maintained in the line is as high as possible consistent with the size of the material to be moved and the prevention of damage to the line and/or to the material conveyed. Because of the wide variation in the size of material, and the weight of the material, it is impossible to give any real range of velocity. How ever, to provide an example, in connection with the cleaning of filter beds where rock varies in diameter from two to three inches down to fines, the velocity of the material passing through the line ranges from 3,000 to 4,000 feet per minute with a blower having' a capacity of 10,000 cubic feet of air per minute. These are optimum conditions of operation and it will be apparent thatlighter weight materials may be moved at speeds within this range in a negative pressure, with a blowerof smaller capacity. As indicated earlier, any stoppage of the negative line pressure during operation causes the material in transitu to settle in the line. Under such circumstances it is most difficult if not impossible to restart the operation without cleaning out all of the lines and starting afresh. The chances of restarting without cleaning are minimal, and so cannot be relied upon practically.

As stated earlier the cross-sectional area of the substantially identical compartments 12a and 12b is far greater than that of the flexible conduit 22 so that the velocity is reduced to the point where the solidsdrop out. In the variable lumen chamber 24 the velocity is reduced but not to the point where the solids drop out of the fluid.

I claim: I

1. Apparatus for picking up and conveying solids entrained in moving fluids in combination a conveyance conduit for the flow of the fluid with the solids entrained therein under negative pressure, a pair of settling tanks connected in parallel to said conduit each having means for removing solids collected therein, a slow-down chamber of larger cross-sectional area than said conduit interposed between said conduit and said tanks, control means operable to direct the fluid passing through said conduit selectively through either one of said tanks only without material interruption of the operation or change of the negative pressure established in the conduit, blower means for establishing a negative pressure in said conduit, and valve means for re-establishing the line negative pressure in the empty tank just prior to the operative switch over.

2. Apparatus for conveying solids to an intended destination comprisinga conveyance conduit, means for introducing solids into said conduit, power means for producing a vacuum through the conduit and chambers as set forth herein, and a settling unit including a tank having a transverse partition arranged to define a negative pressure chamber at one end of said tank communicating With said vacuum source, a longitudinally extending partition arranged to divide the remaining space of -the tank into two settling chambers each having separate means for removing collected solids therefrom and each communicating with said negative pressure chamber, control means to establish communication between the conveying conduit and one of said settling chambers while cutting off communication with the other settling chamber, and valve means between each of said chambers and said negative pressure chamber to close off negative linelongitudinally extending partition arranged to divide the remaining space of the tank into two settling compartments each having means for removing collected solids therefrom and each communicating at one end with the transverse chamber and with the conveyance conduit at 'the other, valve means controlling the communication of said tanks with said transverse chamber wherein only one settling tank is operable at a time and connected to the source of negative pressure, and switch valve means for connecting the conveyance conduit with the operative tank without appreciable diminution of the vacuum maintained or interrupting the operation.

4. A recovery unit for apparatus for conveying solids entrained in fluids under negative pressure in combination fan means for establishing an operative negative pressure, an elongated tank having a transverse partition to define a chamber extending transversely across said tank adjacent one end thereof and directly communicating with the negative pressure of said fan, a longitudinally extending partition arranged to divide the remaining space of the tank into twb adjacently positioned settling compartments, each of said compartments having means for removing solids collected therein and having means communicating with the common transverse chamber, means at the end of said tank opposite to said chamber for connecting said compartments to a common conveyance conduit, switch means for operatively connecting only one settling compartment to the conveying conduit at a time, and valve means controlling the communication of the transverse common chamber with the settling compartments so that thecommon chamber communication is open inany one settling compartment when the same is operatively connected to the conveying conduit, and valve means operative to permit establishment of the negative pressure from the common chamber just prior to the switching connection to the conveying conduit so as to permit continuous use without appreciable diminution of the vacuum maintained or the continuous operation.

5. A recovery unit for apparatus for conveying solids entrained in fluids :at a relatively high velocity of the order of 3,000 to 4,000 feet per minute, in combination fan means for establishing the operative negative pressure, an elongated tank having a transverse partition arranged to define a common chamber extending transversely across said tank adjacent one end thereof and directly connected to the negative pressure of said fan, a second longitudinally extending partition arranged to divide the remaining space of the tank into two adjacently positioned and substantially equal parallel settling compartments, each of said compartments having individual means operable to remove solids collected therein, said compartments each having a cross-section greatly in excess of the cross-section of the common conduit, valve means for connecting said transverse chamber to each settling compartment to the source of vacuum, means at the opposite end of said tank for connecting both said compartments to a single conveyance conduit, a single flexible conveyance conduit, switch means for connecting one settling compartment at 'a time to the conveyance conduit, filter means in each settling compartment to filter the fluid passing through to the common chamber, and means to connect the empty settling compartment to the common chamber without disrupting or changing the operation of the other just prior to switching the empty compartment to operative engagement with the conveyance. conduit and to accom- .plish the switch without substantial diminution of the vacuum maintained or the continuous operation.

6. A recovery unit for apparatus for the conveyance of solids by, means of fluids at a negative pressure, in combination, a flexible conduit for picking up and conveying solids entrained in a fluid of negative pressure at velocities of the order of 3,000 to 4,000 feet per minute, fan means for establishing and maintaining the operating negative pressure throughout the apparatus, a tank in juxtaposition to said fan means having a transverse partition arranged to define a common chamber extending transversely across said tank, said common chamber directly communicating with the negative pressure of said fan, a second but longitudinally extending partition arranged to divide the remaining space of the tank into two substantially equal adjacent settling compartments each having individual means for removing solids collected therein, said settling compartments having an area greatly in excess of the conduit, valve means controlling the communication between said common chamber and each of said compartments, switch means for connecting said compartments to the conduit line one at a time, means to reduce the pressure in the empty settling compartment just prior to being connected to the conduit to provide continuous operation without appreciable change of the negative pressure established, and means just prior to said switch means for reducing the speed of travel in the conduit line.

7. The continuous method of picking up, conveying and delivering solids in a fluid line com-prising the steps of establishing and maintaining a substantially uniform and constant negative pressure fluid in the conveying line for conveying entrained solids during operation at velocities of the order of 3,000 to 4,000 feet per minute, delivering said fluid and entrained solids to one of a pair of substantially identical chambers at substantially the same negative pressure but at reduced velocity to cause the solids to drop out, filtering the fluid as it leaves the chamber, establishing a common chamberat substantially the same negative pressure which operatively communicates with each of said chambers individually, connecting the fluid line with only one chamber at a time, variably reducing the velocity in the line immediately prior to connecting the conveying line to the chamber but without causing the entrained solids to drop out of the conveying fluid, establishing the negative line pressure in the second chamber from said common chamber just prior to its connection with the conveying line, connecting the said second chamber to the conveying line and common chamber while disconnecting the first chamber from the common chamber and the conveying line, and emptying said first chamber in any conventional manner, said steps producing a continuous operation without any substantial reduction in the conduit negative pressure.

8. The continuous method of picking up, conveying and delivering solids in a negative pressure fluid line comprising the steps of establishing and maintaining a substantially uniform and constant negative pressure fluid during operation in a portable conveying line of substantial length operating in any direction having a pick-up nozzle, employing the negative pressure fluid in the line to pick up solids through the nozzle and maintain a substantially constant flow of solids-in said line,

delivering the fluid and entrained solids to one of a series of parallel chambers at substantially the same negative pressure but at reduced velocity to cause the entrained solids to drop out of the fluid by gravity in said chamber,

filtering the fluid as it leaves the operative parallel chamber,

establishing in a common chamber substantially the same negative pressure as that of the conveying fluid,

which communicates with each of said parallel chambers in a planned sequence,

connecting the fluid line with only one of said parallel chambers at a time,

establishing the negative line pressure in the next parallel chamber in sequence by communication with the common chamber just prior to the connection with the fluid line, and connecting said next parallel chamber to the fluid line and common chamber while disconnecting the prior parallel chamber from the common chamber and the conveying line without interrupting the operation of the conveying line or substantially changing the negative line pressure. 9. The continuous method of picking up, conveying and delivering solids in a negative pressure fluid line comprising the 'eps of establishing and maintaining a substantially uniform and constant negative pressure fluid during operation in a portable conveying line of substantial length operating in any direction having a pick-up nozzle,

employing the negative pressure fluid in the line to pick up solids through the nozzle and maintain a substantially constant flow of solids in said line,

slowing the speed of the fluid and entrained solids in the line just prior to delivery,

delivering the fluid and entrained solids to one of a series of parallel chambers at substantially the same negative pressure but at reduced velocity to cause the entrained solids to drop out of the fluid by gravity in said chamber,

filtering the fluid as it leaves the operative parallel chamber,

establishing in a common chamber substantially the same negative pressure as that of the conveying fluid which communicates with each of said parallel chambers in a planned sequence,

connecting the fluid line with only one of said parallel chambers at a time,

establishing the negative line pressure in the next parallel chamber in sequence by communication with the common chamber just prior to the connection with the fluid line,

connecting said next parallel chamber to the fluid line and common chamber while disconnecting the prior parallel chamber from the common chamber and the conveying line without interrupting the operation of the conveying line or substantially changing the negative l-ine pressure, and emptying the prior parallel chamber of the solids.

References Cited by the Examiner UNITED STATES PATENTS 1,240,752 9/1917 Middleton 30259 3,106,427 10/1963 Mortimer 302-28 FOREIGN PATENTS 406,145 2/1934 Great Britain.

HUGO O. SCHULZ, Primary Examiner.

ANDRES H. NIELSEN, SAMUEL F. COLEMAN,

Examiners.

Claims (1)

1. APPARATUS FOR PICKING UP AND CONVEYING SOLIDS ENTRAINED IN MOVING FLUIDS IN COMBINATION A CONVEYANCE CONDUIT FOR THE FLOW OF THE FLUID WITH THE SOLIDS ENTRAINED THEREIN UNDER NEGATIVE PRESSURE, A PAIR OF SETTLING TANKS CONNECTED IN PARALLEL TO SAID CONDUIT EACH HAVING MEANS FOR REMOVING SOLIDS COLLECTED THEREIN, A SLOW-DOWN CHAMBER OF LARGER CROSS-SECTIONAL AREA THAN SAID CONDUIT INTERPOSED BETWEEN SAID CONDUIT AND SAID TANKS, CONTROL MEANS OPERABLE TO DIRECT THE FLUID PASSING THROUGH SAID CONDUIT SELECTIVELY THROUGH EITHER ONE OF SAID TANKS ONLY WITHOUT MATERIAL INTERRUPTION OF THE OPERATION OR CHANGE OF THE NEGATIVE PRESSURE ESTABLISHED IN THE CONDUIT, BLOWER MEANS FOR ESTABLISHING A NEGATIVE PRESSURE IN SAID CONDUIT, AND VALVE MEANS FOR RE-ESTABLISHING THE LINE NEGATIVE PRESSURE IN THE EMPTY TANK JUST PRIOR TO THE OPERATIVE SWITCH OVER.

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