US2744792A - Apparatus for conveying comminuted materials - Google Patents

Description

y 1956 J. 5. FINN APPARATUS FOR CONVEYING COMMINUTED MATERIALS INVENTOR.

JOHN S. FIN/V ATTORNEY Filed March '7, 1952 awn? AH \SFRSM MES:

States Patent APPARATUS FOR CONVEYING COMMIINUTED MATERIALS John S. Finn, Burlingame, Calif., assignor, by mesne assignments, to William H. Mead, akland, Calif. I

Application March 7, 1952, Serial No. 275,360.

3 Claims. (Cl. 302-14) This invention relates to a method and an apparatus for moving granular materials from one location to another. More specifically the invention relates to a method and an apparatus for picking up granular material in afluid stream, conveying the material to another location, and depositing it there. Still more specifically, the invention relates particularly to a pickup nozzle for such an apparatus.

Suppose, for example, that there has been a sand-blasting operation and that the sand has accumulated on the floor. With this invention the sand can be picked .up ofl the floor in a strong suction current, conveyed to a separation tank, separated out of the suction current, and deposited in a reservoir. The invention saves or replaces hand labor, and provides a less expensive and more efiicient way of moving granular material. I

Important problems have been solved by this invention, and one instance where the invention has proved-invaluable will be related to give some idea of its importance. Mo st ships and submarines have tanks which must periodically be sandblasted. These include ,fuel

storage tanks, ballast tanks, cargo tanks used for the trans portation of edible oils, and many other types.

such tank, often located at the bow of a cargo ship, is wedge-shaped and there is no appreciable fiatfloor or place to walk around inside it. high, twenty feet long, twenty feet across at the;rear,

Many of these tanks are diflicult to work in; for example,.one

It is E about thirty feet cult to un-plug the duct, but this had to be done before operation could be resumed. This plugging also tended to overload the vacuum pump and otherwise-damage the device. p

The present invention solves this problem by a novel The complete apparatus includes a strong vacuum pump which produces a low pressure condition in a ductlsysterm. The granular material is drawn into the system at the nozzle, where a current of water impinges with]. it. The wet material is carried in a high-velocity stream into a cyclone separator, wherethe solid material is centrifugally thrown out of the air. vThe wet sand maythen be passed out into a storage vessel in the open atmosphere, through a series of valves.

In the drawings: 1

Fig. l is a view in elevation and partly in section of an apparatus embodying the principles of the invention,

some parts being shown diagrammatically.

Fig. 2 is aside view in elevation and in. section of a nozzle.embodying the principles of this invention and;

through which the granular material is picked up. v

Fig. 3 is a bottom plan view of the nozzle shown in I Fig. 2.

Fig. 4 is a view in section throughthe nozzle, along the line IYIV in Fig. 2.

Fig. 5 is a view in end elevation of the nozzle looking at Fig. 2 from the right hand end.

Fig. 6 is a top plan view of the cyclone separator, some 5 parts beingbroken away and shownin section.

and it narrows to a point at the front. Periodicallyall] these different types of tanks have to be cleaned, and open a separation station, which is preferably adjacentthe I location where the granular material is to be deposited.

sandblasting has been the preferred cleaning method. As the operator starts at the bottom and works up the walls,

the sand accumulates in the bottom of the tanlo.

When he has finished, a large quantity of sand has. ac-

cumulated there, and it must all be removed before any]- liquid can be stored in the tank. Z J Her'etofore it has taken eighty man-days to remove the sand from such a tank. Twenty men, working full,

; trifugal force may be produced by whirling the air stream time with shovels and a bucket line, have taken'four The method ofv the invention begins with the'impor-h tant step of drawing the granular material into a high velocity suction stream, while at the same time impinging a stream of water on the granular material at the point i where the material is drawn into the stream. This step is what prevents plugging of the suction duct.

The wet granular material is then conveyed by a swiftly.

moving suction current, under low pressure conditions, to

Then the granular-.material is removed from the air,

preferably by centrifugal force with or without a simultaneous lowering of velocity of the air stream.' The cenaround in a circle or by a violentchange in direction Once the granular material has been separated out, the

. air stream is conveyed away from the separation station.

the abrasive is removed from the air stream. Then the abrasive is transferred to the desired location in the outer air without affecting the vacuum conditions in the conveying system or at the separator.

In accomplishing this method, the main problemitha t up until that blocked oi the suction duct completely,.

and then the device ceased to operate. It was then difii- When-the material is separated out from the air stream, it is. dropped and collected in an atmosphere whichis still under lowrpressure conditions. Thenext important current. This may be accomplished by transferring the collected material into an enclosed area which may be. isolated from the collection area, isolating this enclosed area, raising the pressure therein to substantially atmospheric, and finally transferring the material out into the open air. Preferably this is done by dropping the collected material ,into an intermediate. collecting zone, iso-= lating, the intermediate zone, introducing airthereto, and. then dropping the material out'of. the intermediateg'zone'f into the open atmosphere. Then the isolated area is re Patented May 8, 1956 joined to the collection area and a vacuum induced therein? by the air stream; The-velocity oftheair" streamis suflicient to restore the vacuum instantaneously without substantial disruption.

The" advantages'of the above descrilied method are" (3?): iv separating and unloading unit 30 between the" nozzle 2'0 and the pump unit'l'tl; where the granular material 15 isremoved from the air stream and subse quently transferred to the atmosphere; A conduit 1-1 conveys'tlie granular material 15 in ahigh-velocity, low pressure stream from thc-nozzle'20 to the unit 30; and a conduit 12 conveys the air from" the unit 30' to'the' pump unit 10. The unit 30 may be locat'ed as far as 300 feetfiom thepump' andas'far as 100 feet from the nozzle-20':

So far as the blower-unit 10is concerned, anysuitable" means" of producing"; a' vacuum may be" used and for that reason it is not' illustrated in detaill Preferably the motor (not'shown') will be about 10-HE P; and he capable of producing a vacuum of 12 to 15 inches of mercury and move about 325 cubic feet of air per minute; Tfieremaybe a'filterunit 13 adjacent the blower'10, to remove from the air stream any'solids-which" mayhavebeen carried out of' the separator 30.

The nozzle (see Figs: 2 to 5) preferably comprises a tube 21 with an" open cylindrical upper end22' connected to the*conduit'11 and aflattened open lower end or: mouth" 23- by which the material 15 can be sucked in even when only'a smallamount of 'abrasive' remains on" the floor: Preferably the nozzle interior is coated with arubber *liner'24 to prevent the abrasive': 15" from wearing out the tube 21".

The nozzle 20'' is'supplied with" awatersuppl-y tub'e 25havinga fitting 26 at its upperend to which'a water ho's e'- 27"i's"securedi The tube 25' may be rounda-t the which opensdirectly into' the. primary tube" 21 adjacent the'mouth 23; For a'nozzle 20. three. inches'in' diameter zit-22, the diameter'ofthe fitting-maybe about A" of an'inch; andthe' fitting 2 6' may lie'about eighteeninches" fromthe mouth23; A' suitable mouth 23*may be about G'inclieswidie by /8 inch high; and the end 28 maybe about tl1'e*same=width; /8" of an inch high andlie about 1 inchesfromtlie mouth" 23. Thisair stream impinges with. the incoming" material t. 23" adjacent the mouth 22. andl'teeps"v it" from packing together:

The nozzle" 20 'is'" a very: important" element in: this combination. Prior: to its use; thepump 10wou1d"b'ea come overloaded when too much abrasive was" sucked in; andon many 'occasions'the: duct 11" became" completelypluggedwith sand; and the whole operation had 'to'. be stopped untilthe" duct 11. could be cleaned. out? The" provision of a; supply -ofwater through-the Hose 27 and the tube 255 eliminates: this plugging and choking; and assures" a' rapid; evenflow" of" sand or other" material through the duct 11 to the separating; and. unloading; unit"30.i

The-unit30lincludes a1cyclone'31 (see Fig, 6) where the wet" solid material is unloaded from" the" suction stream: Preferably the. cyclone. 31 comprises a sub stantially' annular chamber; 32" much larger in cross;

section than the conduits 11 or 12 and located between the substantially cylindrical outer" wall' 33* of" the unit 30 and a cylindrical wall 34 which depends from the closed top of the unit 30. Preferably the outer wall 33 flares out toward its lower end so that the wet material will be more easily thrown out from the air stream into the hopper 40 below; Preferably the cyclone 31 and the surfaces adjacent to it are lined with rubber 35 to" protect them from the wearing 'action" of" abrasive. The air stream from the duct 11' preferably enters the cyclone 31: tangentially thereto through: the opening 36;. and the. wet. solid. particles; are: thrown i out: against the outwardly slopingvwalls. 33. Anyv remaining wet granular material is' thrown out" when the suction" stream passes down out of the annular ch'arnb'err32, is whipped sharply around the depending cylindrical wall 34, and up into the cylindrical outlet chamber 37. Finally, the air stream, with the granular material all removed, ,passes througlithe outlet opening 38 at'the top of' the' chamber ST'andinto' the" duct 12; and the material tallsihtbthe" hopper 40.

The-next step is'to get the wet solid materialoutot" thereclaimer' 30' into the atmosphere-without substantially affecting the'vacuurn-inthe cyclone 31 andin' the ducts" 11 and'12. After being shaken out of the air stream in the cyclone 31, the material falls into'anupper hopper 40" which" preferably has sloping side walls 41, anddown toward an opening" 42- through the bottom" of thehopperAi). A-valve43controls the passage of the material from'tlre-npper'hopper 4010 alower'hoppei'45f This enables" the upper' hopper 4010 be" maintained" at" avacuum and enablestlie l'ower hopper 4'5"to be alter-- nated between vacuum pressure (when thevalve 43"is" open) and atmospheric pressure (when the valve'43is' closed):

The intermediate valve 43'- may -be time-controlled" by a timer 46; and-maybe operated by airpr'essure' from a compressor47. Thetimerswitch' 46 may periodically energize or do -energizea' solenoid (not shown) that controls the aircircuit that operates 'tlr'e'valve 43. The intervals are setfor optimum" performance with the" material concerned, usually about 1'5 seconds open followecl by 15' seconds 1 closed;

Materialentering the'hopper 45 falls downtheslbpiirg walls 48 toward the opening- 49', where an unloader VaIve-S'Gat'the bottom of the'lbwer'hopper 45 maybe gravity operated; a counterbalz'ince- 51' beingsecured to" it. The counterbalance 51may'be" set toopen the valve when the'pressure on' the valve 50"is equivalent-to about one" pound of sand"at"atmospheric' pressure. as the chamber 45" is under a vacuum, the weight of: the wet sand" will not open" the valve" 50; but when the valve 43 is closed; air maypass through a; conduit (not shown) into the hopper 45; and'lwhenrthe vacuum" is broken; the valve' 50" willI-be opened. it material has accumulated on it;

Operation- In operation the powerful pump 10' exerts"a" consider= able suction force through the ducts 12. and" 11 and on-the-nozzle' 20: The source of water'is' turned on to" deliverwater'to the-nozzle'2'0; via'theihose 27, fitting, 26$ and tube 252 Thenozzle 20 may then; be inserted inf-the dry'solid' comminutedmaterial 15 which is'to be moved-I As the material 15"is suckedin th'roughith'e mouth23, it i'srnet by/a stream" of water: comingrtlironglr; the? tube 25.. The" water mixes with the material 15*" adfacent the'mouth' 23 to' wet'it" down" and"tlierehyprevent it from blocking the". duct 11" and" overloading the motor '10l The/Wet material 15 is conveyed at"considerable-veloc= ityfromi the nozzle 20tl1rough'. the duct 11 and into. the cyclone; 31 througlr the" tangential opening; 36:" The air" streamwhirls around the" annularchamlien 32, and the solidmaterial is'thrown out against theoutwardly sloping? walls 33 and down into the hopper 40. Simultaneously there is a decrease in the velocity of the air stream, and this aids the separation action. Any granular material which remains is cast out of the suction stream when the air stream Whips down below the wall 34, up-into the cylindrical chamber 37, and out the opening 38 into the duct 12.

The solid material falls down into the hopper .40. During the initial half cycle of operation, the valve 43 is open, the valve 50 is closed, and the hopper 45 is under a vacuum. The material falls into the hopper 45 and builds up over the valve 50. The low pressure inside the hopper 45 enables the counterweight 51 and the air pressure outsideto keep the valve 50 closed.

At the end of the first half cycle (which may be about seconds in a particular case), the timer switch 46 closes the valve 43. The solid material then builds up over the valve 43, with the hopper 40 constantly being kept at a vacuum.

At the same time, a conduit (not shown) conducts air under pressure into the hopper tank 45. When the pressure builds up to a substantially atmospheric level, the weight of the solid material and the air inside overbalance the counterweight 51 and the outside atmosphere and open the valve 50. The material then falls out into a suitable container. When all the material has fallen out, the valve 50 closes automatically. 7

As the end of the second half cycle is approached, the

that the approximately 2 cubic feet of air in the hopper pickup opening and a secondary tube connected with said main tube adjacent said pickup opening; a source of water connected to said secondary tube; a conduit connected to the main tube of said nozzle for conveying therethrough said material; suctions means connected to said conduit to induce the flow of a gaseous current therethrough under relatively low pressure conditions; a separation cyclone connected to said conduit; and valve means for passing the separated material out to the atmosphere without seriously afiecting said suction current.

2. The apparatus of claim 1 in which said nozzle comprises a main tube having one end adapted to be con- 45 do not even cause a noticeable momentary slowing of the air stream. The operation of separation remains unaifected and operates continuously.

What is claimed is:

1. An apparatus for moving granular material from one location to another, comprising a pick-up nozzle adapted to receive said granular material in a gaseous suction current said nozzle having a main tube with a nected to the conduit and having at its opposite end a mouth which is generally flat in cross-section, and a secondary tube extending from an opening inside said main tube and adjacent said mouth and connected at its opposite end to a supply of water, whereby the water will impinge on the granular material as said material is picked up at the mouth of said nozzle, and said material will be thoroughly wet down.

3. An apparatus for moving granular material from one location to another, comprising a pick-up nozzle adapted to receive said granular material in a gaseous suction current, said nozzle having a main tube with a pickup opening and a secondary tube connected with said main tube adjacent said pickup opening; a source of water connected to said secondary tube; a conduit connected to themain tube of said 'nozzle for conveying therethrough said material; suction means connected to said conduit to induce the flow of a gaseous current therethrough under relatively low pressure conditions; means connected to said conduit for separating the wet granular material from the gaseous current; and valve means for passing the separated material out to the atmosphere Without seriously affecting said suction current.

, References Cited in the file of this patent I UNITED STATES PATENTS

Claims (1)

1. AN APPARATUS FOR MOVING GRANULAR MATERIAL FROM ONE LOCATION TO ANOTHER, COMPRISING A PICK-UP NOZZLE ADAPTED TO RECEIVE SAID GRANULAR MATERIAL IN A GASEOUS SUCTION CURRENT SAID NOZZLE HAVING A MAIN TUBE WITH A PICKUP OPENING AND A SECONDARY TUBE CONNECTED WITH SAID MAIN TUBE ADJACENT SAID PICKUP OPENING; A SOURCE OF WATER CONNECTED TO SAID SECONDARY TUBE; A CONDUIT CONNECTED TO THE MAIN TUBE OF SAID NOZZLE FOR CONVEYING THERETHROUGH SAID MATERIAL; SUCTIONS MEANS CONNECTED TO SAID CONDUIT TO INDUCE THE FLOW OF A GASEOUS CURRENT THERETHROUGH UNDER RELATIVELY LOW PRESSURE CONDITIONS; A SEPARATION CYCLONE CONNECTED TO SAID CONDUIT; AND VALVE MEANS FOR PASSING THE SEPARATED MATERIAL OUT TO THE ATMOSPHERE WITHOUT SERIOUSLY AFFECTING SAID SUCTION CURRENT.

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