CA1071270A - Discharge device - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The invention finds application in the discharge of refuse material from a vacuum conveying system, while the vacuum in the system is maintained during discharge. The refuse material has heavier and lighter fractions, the lighter fractions comprising fibrous material. The device includes a terminal material-receiving room attached to the conveying system, and an elongate material-compressing chamber aligned with and at one end in open communication with the material-receiving room; the chamber having a material-discharge port at the other end. A material propelling and compact-ing member moves portions of the material from the room into the compression chamber, and means associated with the compression chamber cause the material to form a plug which substantially seals the discharge port against penetration of air into the system while the plug is being discharged through the port,

Description

~ 07~L~zq The present invention refers to a discharge device for use in connection with the discharge of refuse material for example, household garbage, containing specifically heavier and lighter fractions, said lighter fractions comprising fibrous material, from a vacuum transport system, in particular a discharge device which, during discharge, permits a state of vacuum to be maintained in the system.
This application is a division of Canadian application serial number 163,487 filed February 12, 1973.

A problem in the discharge of material from a vacuum transport system has been the maintenance of a state of vacuum even under those periods when material separated from the conveying air stream is discharged from the system. Attempts have been made to solve this problem by various types o sluice valves. Such valves, however, have been subjected to repeatedly recurring interruptions of operation due to -penetration of dischargedmaterial into various parts of the valve mechanism. These valves also have been an expensive addition to the system without performing any function other than to discharge the conveyed material with the vacuum in the system maintained. For example, it has not been possible to use them for feeding the conveyed material into some kind of receiver such as containers, trucks, bags or the like.
Quite unexpectedly it has been discovered that in spite of its extremely unhomogeneous composition ordinary household garbage and similar refuse may be compressed to form a tight plug which even during more or less continuous discharge prevents air from penetrating through the discharge opening to an extent disturbing or removing the state of 30 vacuum. The primary object of the present invention is a device for discharging loose unhomogeneous material such as ` household garbage from a vacuum conveying system with the state of vacuum maintained by means of a plug of the discharged material formed in the discharge opening.
Garbage and similar mixed material, such as certain types of industrial refuse, comprise as a rule a comparatively high percentage of fibrous material the recovery of which for renewed use is an important task in respect to the menacing fibre shortage in the world. The fibrous material in garbage to the greatest part comprises loose paper or wrapping paper released from its contents, such paper during suction-transport being in-clined to follow with the air stream at higher velocity and sub-stantially separate from the heavier material components.
According to this invention there is provided a device for discharging refuse material from a vacuum conveying system, while the vacuum in the system is maintained during discharge, comprising in combination; (a) a material receiving chamber for connection to said system; (b) an elongate material compressing chamber having a first end and a second end, said material com-pressing chamber being aligned with said material receiving cham-ber and adjacent said first end forming an unrestricted continua-t1on of said material receiving chamber, and at said first endbeing in open communication with said material receiving chamber;
(c) means defining a discharge port at said second end of said material compressing chamber; (d) a material propelling member movable within said chamber to move portions of the material from said material receiving chamber into said material compressing chamber; and (e) means associated with said material compressing chamber for transversely compressing said material, said means being laterally movable between a first position in alignment with the internal wall surface of said material compressing chamber be-yond the reach of said member permitting free material movementthrough said material compressing chamber under the action of ~071'~70 said member and a second position restricting the cross-sectional area of said material compressing chamber and compressively com-pacting and arresting the movement of the portion of the material positioned within the reach of said laterally movable means.
While, unavoidably, a part of the loose fibre material will be entangled in the heavy material fraction, a very simple arrangement embodying the present invention may enable up to 80~
of the total fibrous material forming part of e.g. normal house-hold garbage to be separately discharged. The remaining fibrous material following with the heavy material will in such a case not necessitate any additional separation measures. In very -specific cases, however, means may be provided enabling the per-centage of loose paper in the collected and conveyed material to be increased at the expense of the proportion of heavy compact fibrous material discharged together with the heavy material.
For example, at positions where fibrous refuse is produced in particularly great amounts and possibly in packed, tied or bound condition, specific fibre material introduction openings may be combined with means for subdividing the agglomerated fibrous mat-erial into pieces which are inclined to follow with the air stream rather than to behave as heavy fraction material.
The invention will be further understood from the follow-ing description by way of example with reference to the accompany-ing drawings, in which:-Figure 1 is a schematic perspective view of a self-sealing discharge device;
Figures 2 - 5 are schematic sections of four other such discharge devices, Figures 2 and 5 illustrating embodiments of this invention; and Figure 6 is a schematic representation of a terminal .

- -~071'~70 station of a pneumatic garbage conveying system with material discharge performed in two steps.
Devices according to this invention are primarily intend-ed to be used in the discharge of household garbage and similar loose material consisting of or comprising fibrous material from a vacuum conveying system to containers or vehicles for removal of the material to, for example, a destruction station. Any kind of material can be treated which can be compressed to a sealing plug under considerable reduction of the volume of the loose material. Household garbage corresponds to this condition provided it contains at least a normal percentage fibrous mater-ial alone or in addition to other soft wet components such as kitchen refuse. A separately collected light-weight fraction of household garbage is particularly suited for this kind of self-sealing discharge.
Figure 1 shows a device which comprises a combined mat-erial receiving room and compression chamber 1 having rectangular cross-section, a piston 2 reciprocating therein and a garbage supplying device comprising a hopper 4, the bottom opening 3 of which coincides with an introduction opening on the upper side of the material receiving room 1. In a way not shown, hopper 4 at its upper end is sealingly connected to a vacuum conveying system, said hopper, for example, forming the lower end of a device, e.g. a cyclone, for the separation of conveyed material from the conveying air. A restricted outlet 5 of circular cross-section forms a continuation of chamber 1.
Obviously, compression chamber 1 and piston 2 might have cylindrical shape. Preferably, piston 2 is provided with a check valve or similar device (not shown) permitting air to .: ~
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~07~Z70 penetrate, during the return stroke of the piston 2, into the space formed between the plug of material under discharge and the piston as otherwise the plug might be sucked back into the compression chamber.
The piston rod 6 of piston 2 extends, suitably through a gasket (not shown), through an aperture 7 in the -4a-10~ 70 rear wall of chamher 1, ~hereby air is prevented from penetrating into the system even if the piston is not in completely sealing contact with the wall of the chamber.
The conveyed material discharged from the conveying system falls down into hopper 4 and, while piston 2 is retracted, also into the combined material receiving room and compression chamber. During the compressing stroke of piston 2 towards the right in Figure 1, the material is compacted into the restricted outlet 5 to form there a plug preventing air from penetrating into the system in spite of the fact that vacuum is prevailing there.
During the initial phase of the operation of the vacuum conveying system before a material plug has been formed in outlet 5, piston 2 should be in a position past opening 3 and slightly extending into the adjoining portion of the compression chamber. In this position the piston will counteract inhalation of air from outlet 5 to a degree sufficient to permit the state of vacuum in the system to be maintained. With the piston maintained in this position the suction conveying system should be operated until a sufficient supply of material has collected upon the piston in hopper 4.
Prior to starting operation of the piston to permit the material collected thereon to fall down into the receiving room and to be compressed in the compressing chamber the suction thr~ugh the discharge device will suitably be temporarily interrupted by the closing of a valve in the line connecting the discharge device with the suction machinery.
During su~ temporary shut-down the piston is caused to perform a couple of working strokes permitting the material previously collected on the piston to fall down into the ~0~71Z70 receiving chamber and to be compacted as previously described in the restricted outlet 5 to form an initial plug. Thereafter the state of vacuum in the discharge device may be restored again and operation may continue without interruption as long as a com-pacted plug of material is maintained in outlet 5. -The port opening of the outlet 5 has an area correspond-ing to the degree of compression achievable in the material so that the restricted outlet portion 5 is continuously maintained filled with the tightly compacted plug of material which during continued compacting of additionally supplied material will be discharged in successive portions through the port of the outlet.
The above-described procedure of temporarily interrupting the state of vacuum in the discharge device may be undesirable and can be avoided by specific arrangements provided in order to pre-vent air from penetrating through the outlet port prior to forma-tion of a permanent plug of material therein. In Figures 2 - 5 there are shown various devices serving this purpose.
The embodiment of the invention shown in Figure 2 com-prises a compression chamber 11 in which a piston 12 is movable and which is extended by a restriction chamber 15 the passage through which is restricted by a sleeve or cuff 16 of impermeable pliable material. The sleeve 16 forms the inner boundary wall of an annular, outwardly closed pressure chamber 17 that may be fill-ed with pressure fluid through an inlet 19. The pressure expands the sleeve 16 to compress the material within to form a plug which, in cooperation with the pliable wall of the sleeve, prevents air from penetrating into the system. About the sleeve 16, ribs 18 extend in continuation of the compression chamber 11 to prevent the sleeve from bulging outwardly.
The device shown in Figure 2 may be modified so that ~` .

` ~071270 the sleeve or cuff 16 forms the inner boundary of a space which is open to the surrounding atmosphere within ribs 18. In this case the sleeve should be made from pliable but comparatively deformation-resistant material which normally constitutes a restriction of the discharge passage for the material to such an e~tent that a sealing plug of material is formed therein.
Referring again to Figure 2, a continuation of the re-stricted passage 15 is formed by a section 20 having the same cross-sectional shape as the compression chamber 11. The mater-ial discharged from the compacting section 15 will expand in thesection 20 whereby its discharge from the discharge duct is facili-tated. During an initial phase of operation when a plug ~f mat-erial has not yet been formed within sleeve 16, the outlet port of passage section 20 may be closed by a lid 21 pivotally journall-ed adjacent said port and adapted to form a vacuum seal for the entire system during this phase of operation, said lid being open-ed under the action of the material fed forward or by other means after formation of the sealing plug within sleeve 16 and pene-tration of the previously compacted material into passage section 20.
Depending on the kind of material conveyed, an arrange-ment according to Figure 2 or its modification mentioned above may also be used in such a way that the sealing plug of material is formed within section 20 by compacting material fed forward against lid 21, and after formation of a sufficiently compacted and sufficiently long plug, lid 21 is opened for continued dis-charge of the plug of material with the state of vacuum maintain-ed. In this case, sleeve 16 in the first place serves the pur-pose of preventing previously fed material from being sucked backward during the return stroke of piston 12. In this case, the sleeve suitably consists of a material which, under the sucking ~ ~:

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107~Z70 action produced by the retraction oE the piston, expands in-wardly and thereby steadily squeezes the material enclosed within the sleeve.
The device shown in Figure 3 comprises a cylindrical compression chamber 30 with a piston 31 movable therein. The outlet opening of the compression chamber is adapted to be clos-ed by means of a lid 32 against which, during an initial phase of operation, a garbage plug is formed. When the plug has been formed with sufficient tightness and lid 32 is opened, the vacuum seal is subsequently maintained by the plug of material under discharge. A rearward movement of previously fed material, for example under the action of the return movement of piston 31, is counteracted by points or prongs 33 extending inwardly from the wall of the compression chamber. The points not only retain the material in the forward portion of the compression chamber but also act to facilitate the formation of a plug by restricting the free passage area of the duct.
The device shown in Figure 4 comprises a fully cylindri-cal compression chamber without any restriction which is only provided with a lid 41 for preliminary sealing of the system un-til the material plug has been formed in the outlet. In this case the material must have a comparatively high friction against the wall of the compression chamber and comparatively high content of sealing enhancing components such as fibrous material, and the chamber between the forward dead point of piston 42 and the outlet port at lid 41 must have such a length that a sufficiently long and sufficiently solid material plug is formed which will not disintegrate prior to having passed through the discharge port and which aLl the time offers a sufficiently strong resis-tance to discharge to enable the plug to be continuously built-up .

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107~;~70 from the inner end by additionally supplied material with the state of compactness and thereby the sealing action maintained.
However, in order to obtain a compression of the material against the wall of the compression chamber 40 it may be advantageous to provide on the forward end of piston 42 an element, for example in the form of a cone 43, which acts on the material instead of a restriction of the compression chamber in the direction towards the outlet as described by reference to Figures 1 to 3.
The embodiment of this invention shown in Figure 5 com-prises a cylindrical compression chamber S0 and a piston 51 mov-able therein. In this embodiment, the necessary preliminary sealing of the outlet preventing air from penetrating and causing a plug of sealing material to form can be obtained by moving a disk 52 laterally transversely of the compression chamber 50.
When a sufficiently compact and sufficiently long material plug has been formed behind the disk 52, the disk is moved out of the compression chamber 50 with the aid of a piston and cylinder , device 53, of, for example, pneumatic or hydraulic type. The ~' previously formed material plug forms a sufficient seal against ~ ~
20 the penetration of air through the inlet as well as through the ' ' slot through which the disk 52 extends,. Lateral compression of a previously formed material plug, e.g. during interruptions of ' the operation of the piston 51, can also be effected by lateral ~;
movement of the disk 52 into the compression chamber 50 to a , position such as that shown in Figure 5.
In the device shown in Figure 5, generally no lid is required for closing the outlet port of the compression chamber.
However, such a lid may also be provided in this embodiment, in particular for use in operating conditions in which a solid _ g _ :

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material plug has previously been formed in the compression chamber and an insertion of the disk into the compression chamber, for example during an interruption of operation, is not possible.
Whereas the propelling means for the material in the compression chamber has been described above as a recip-rocating piston or plunger, it is of course possible to de-sign the propelling member in the form of a feed screw extend-ing along the bottom of the material receiving room, i.e., in Figure 1 below the hopper 4, and into the adjoining portion of the compression chamber in close proximity to the wall thereof.
The means, above exemplified as a pivotable lid, for temporarily sealing the material outlet may alternatively be in the form of a solid closure plug of some air-impervious .

10~71'~70 material ha~in~ approximately the sam~ coefficient of friction as a garbage plug to be formed in the compression chamber, such closure plug heing inserted from the outside into the outlet of the compression chamber to serve initially as a seal preventing air from penetrating into the system and as a retainer during formation of the sealing garbage plug which subsequently pushes the closure plug out of the compression chamber.
While various embodiments of a discharge device comprising means for causing the discharged material to form a self-sealing plug in a discharge port have been described in connection with systems for collection and vacuum convey-ance of mixed materials as exemplified by household garbage, the present invention is equally useful in the discharge of refuse material substantially comprising light-weight, highly compressible matter, such as paper refuse coming from specific waste paper collecting systems operating on the vacuum suction principle. The discharge device is used to particular advantage in connection with garbage collecting and conveying systems incorporating discharge means permitting a lighter fraction of the mixed garbage materia~ substantially comprising fibrous material to be discharged separately from the rest of the material, the self-sealing discharge device of the present invention being used in the light-fraction discharge portion of such systems.
In the system schematically shown in Figure 6, mixed material, for example garbage from a conventional collecting system tnot shown~ comprising introduction chutes and connectingconduits, is supplied to a collecting conduit 101 which, via a separating arrangement comprising first and ' ~07,Z70 second separators 102 and 103, is connected to an air outlet 104 leading via a fines separator or filter 105 to the suction side of a syction machine unit 106 from which the air, from which the conveyed material ha6 been removed in separators 102 and 103 and which has been cleaned in the filter 105, is discharged to the atmosphere.
In similar, previously known sy~tems the separation of all the material conveyed in the air ~tream has been performed in a unitary separator, frequently of cyclone type, the material outlet of which was connected to a device for discharging the conveyed material with the ~ubatmospheric pressure maintained in the conduit system. In this case there unavoidably occurred a mixture between the various material fractions so that the material discharged from the system comprised both heavy material such a~ metal and glass articles, and light material such as paper and plastic.
In the system shown in Figure 6 there is obtained a subdivision of the material into two fractions of which the secondarily collected fraction mainly, i.e.
apart from a certain content of plastic material, consists of fibrous material suitable for renewed use. For this purpose, a conduit 110 is branched-off from the substantially straight collecting conduit 101 to feed said first separator, the heavier fraction material conveyed by the air stream along the bottom of the collecting conduit 101 entering into said conduit 110 under the action of gravity whereas the air-borne light material fraction follows with the main stream of the conveying air through the extension of collecting condui t 101 beyond the branching point. The 3~ heavy material from branch conduit 1]0 enters into a ~07~Z70 receiving chaTnber lll having a bottom opening to which a compactor 112 is ccnnected. A reciprocating piston or a conveyor screw forming the propelling element of the compactor feeds the received heavy material in the direction of and through an outlet port into a conveying container, which is attached to the outlet port of the compactor in an air-tight manner and which after filling i8 replaced by an empty container.
When the heavy material enters into chamber 111 a further part of the light-weight material i~ released which, together with the partial air stream pa6sing through conduit 110 and separator 102, is again introduced into the collecting conduit 101 via a return conduit 114. The collecting conduit Lol terminates in the lighter fraction material separator ;~
103, which here i~ schematically illu~trated as a cyclone connected to air outlet 104 at the upper end and an air-tight material discharge sluice 120 at the lower end.
Due to the preceding separation of the heavy material in the first separator 102, the cyclone used for the separation of the light-weight material may be less robust than would otherwise be necessary and its construction can be particularly adapted to the specific character of the residual light material fraction. The reduction in cost obtained thereby and the increase in the effectiveness of separation ~ill to a certain extent balance the increase in co~t caused by the incorporation of the heavy material separator 102 into the system.
It may be mentioned tha~ the discharge of the light-weiqht material through g1uice 120 does not re4uire an equally complicated and bulky arrangement as 30" required for vacuum-tight discharge of the heavy material.

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107~Z70 ~s the light-weight material substantially consists of highly compressible fibrous material, the arrangement may be such that, with the aid of a piston or screw, a successively discharged plug of material is formed in the outlet, said plug during discharge effectively preventing air from penetrating into the suction sys-tem. Any of the constructions described above by reference to Figures 1 to 5 may be used to advantage.
Embodiments of the invention such as those described above with reference to Figures 2 and 5 are particularly suited to use in accordance with a method according to an aspect of the invention, the method comprising the steps of receiving the mat-erial in a receiving chamber connected to the system, and alter-nately feeding the material from the receiving chamber to a mat-erlal compressing chamber aligned with and forming at an end which is open to the material receiving chamber an unrestricted continuation of said material receiving chamber and a discharge port at an opposite end, and compressing the material in the mater-ial compressing chamber by moving means laterally between a first position in alignment with the internal wall surface of the mat-erial compressing chamber and a second position restricting thecross-sectional area of the material compressing chamber, the material forming a seal in the material compressing chamber to maintain said vacuum. The means which effects the compression of the material is the sleeve 16 of Figure 2 or the disk 52 of Figure 5.

Claims (2)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A device for discharging refuse material from a vacuum conveying system, while the vacuum in the system is main-tained during discharge, comprising in combination (a) a material receiving chamber for connection to said system; (b) an elongate material compressing chamber having a first end and a second end, said material compressing chamber being aligned with said material receiving chamber and adjacent said first end forming an unrestricted continuation of said material receiving chamber, and at said first end being in open communication with said material receiving chamber; (c) means defining a discharge port at said second end of said material compressing chamber; (d) a material propelling member movable within said chambers to move portions of the material from said material receiving chamber into said material compressing chamber, and (e) means associated with said material compressing chamber for transversely com-pressing said material, said means being laterally movable between a first position in alignment with the internal wall surface of said material compressing chamber beyond the reach of said member permitting free material movement through said material compressing chamber under the action of said member and a second position restricting the cross-sectional area of said material compressing chamber and compressively compacting and arresting the movement of the portion of the material positioned within the reach of said laterally movable means.

2. A method of discharging refuse material from a vacuum conveying system whilst maintaining the vacuum in the system during discharge, comprising the steps of receiving the material in a receiving chamber connected to the system, and alternately feeding the material from the receiving chamber to a material compressing chamber aligned with and forming at an end which is open to the material receiving chamber an unrestricted continua-tion of said material receiving chamber and a discharge port at an opposite end, and transversely compressing the material in the material compressing chamber by moving means laterally between a first position in alignment with the internal wall surface of the material compressing chamber and a second position restricting the cross-sectional area of the material compressing chamber, the material forming a seal in the material compressing chamber to maintain said vacuum.