WO2003057596A1

WO2003057596A1 - A flow divider for controlling discharge in a vacuum refuse collection system

Info

Publication number: WO2003057596A1
Application number: PCT/SE2003/000006
Authority: WO
Inventors: Kjell-Åke NORLENIUS; Tomas Norlenius
Original assignee: Envac Centralsug Ab
Priority date: 2002-01-09
Filing date: 2003-01-07
Publication date: 2003-07-17
Also published as: DE60304554D1; AU2003201789A1; DK1465823T3; PT1465823E; ATE323040T1; EP1465823B1; ES2262968T3; SE0200041D0; EP1465823A1

Abstract

During emptying of a temporary storage space (1) of a vacuum refuse collection system (10), the flow of a volume of a paper fraction (9) accumulated in the storage space is loosened by dividing it into separate streams. This division of the flow causes discharge of the accumulated paper fraction to be distributed over a slightly longer time, to further suppress any tendency to blockage in the passage of the paper fraction through a discharge valve (2).

Description

TITLE: A flow divider for controlling discharge in a vacuum refuse collection system.

TECHNICAL FIELD

The present invention relates generally to specific fractions of waste or refuse that are being collected for recycling and more specifically relates to the discharge of a paper fraction that has been accumulated in a temporary storage space provided upstream of a discharge valve in a vacuum operated refuse collection system.

BACKGROUND In recent years, recycling of various fractions of refuse has become more and more common, primarily for environmental reasons, such as reduction of pollution and preservation of natural resources, but also in combination with strict economical considerations. One of the fractions being well suited for recycling is the paper fraction. Paper fractions are being collected for recycling both in residential and in office areas. In residential areas the collected paper fraction largely consists of i.e. newspapers or magazines that can be processed to recover fiber of a lower quality than that recovered from the paper fraction of commercial waste collected in office areas.

Collection of the paper fraction for recycling may be performed in various ways, including simply accumulating bags or bundles of paper outside residential buildings and manually throwing the bags or bundles onto a truck. Alternatively, the paper may be accumulated in specific containers at central collection sites from where the containers are lifted onto special trucks and are then transported to a site for further processing.

However, a more sophisticated method is employed in buildings and residential areas being provided with vacuum operated refuse collection systems. In such systems the collection of sorted fractions of waste is performed through the existing refuse disposal chutes in a building or through additional outdoors disposal chutes. In the so called stationary vacuum systems having a central collection station the sorted fractions of waste are directed to separate containers by means of a controlled diverter valve.

All of the described methods of handling sorted fractions of refuse in vacuum operated refuse collection systems, have a common problem that is specifically related to the collection of the paper fraction for recycling. Specifically, paper accumulated upstream of a discharge valve positioned at the lower end of a disposal chute of a stationary vacuum system has a strong tendency to block the passage through the discharge valve and/or to forming plugs that cause blockage in other parts of the system.

SUMMARY

The invention overcomes the above problems in an efficient and satisfactory manner.

A general object of the invention is to provide an improved method of discharging an accumu- lated refuse fraction, such as a paper fraction, from a temporary storage space upstream of a discharge valve in a vacuum operated refuse collection system. In particular, it is an object of the invention to provide a solution to the blockage problem normally occurring during emptying of such a fraction through the discharge valve.

Briefly, the above object is achieved by dividing the flow of the paper fraction. Specifically, the flow of the paper fraction is divided upstream of the discharge valve during discharge thereof. Thus, the flow of the paper fraction is broken up into separate streams and is loosened during emptying, to thereby secure unblocked discharge. At the same time this division of the flow causes the discharge of the fraction accumulated above the flow divider to be distributed over a slightly longer time, thereby further suppressing the tendency to blockage of the passage through the discharge valve.

In an embodiment of the invention, the flow of the accumulated paper fraction is mechanically divided without any blocking thereof, to thereby provide a cost effective method of efficiently discharging the accumulated paper fraction.

In another embodiment of the invention the division of the flow is accomplished by extending a single flow divider into the temporary storage space at a position upstream of the discharge valve. During emptying, said flow divider has the effect of loosening the accumulated volume of the fraction by dividing it. This provides a simple and inexpensive method of significantly enhancing secure discharge of the accumulated fraction. In a further embodiment of the invention the single flow divider is extended into the storage space approximately through a centre line of the storage space, thereby securing that the flow is divided without any blocking thereof by the flow divider.

In a further embodiment of the invention, the flow divider is linearly extended into the storage space through a wall surrounding the latter and in a direction being transversal to the direction of flow through the storage space. This provides for an effective breaking up and thereby loosening of the flow of the fraction and simultaneously presents a practical as well as functional method.

In an embodiment where the invention is employed in a storage space having a substantially circular cross section, the flow divider is preferably extended along a diameter of the space. To be fully effective, the flow divider is extended from a retracted position outside the storage space to an active position extending across at least a major portion of the space.

In a further embodiment of the invention, the extended flow divider is retracted from the storage space before the discharge valve is closed after discharge of the paper therethrough. This will secure that any refuse that might get stuck on the divider during emptying is discharged before closing the valve.

Another object of the invention is to provide an improved temporary storage space of a vacuum refuse collection system permitting very effective discharge of an accumulated fraction therefrom and thereby presenting a solution to the problem of avoiding blockage in the system. In accordance with the invention, this is accomplished by means of a single flow divider being extendable into the storage space and retractable therefrom to secure unblocked discharge of an accumulated fraction in accordance with the basic principles of the invention.

These and further objects of the invention are met by the invention as defined in the appended patent claims.

The present invention provides essential advantages over the state of the art by considerably reducing the risk of blockage occurring at the discharge valve as well as in other parts of the system during discharge and by thus allowing the accumulation of larger amounts the fraction in the storage volume before risking blockage.

Other advantages offered by the present invention will be readily appreciated upon reading the below detailed description of embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and further objects and advantages thereof, may best be understood by making reference to the following description taken together with the accompanying drawings, in which:

Fig. 1A is a partial side view illustrating a first embodiment of the temporary storage space according to invention, with portions of the wall of the storage space cut away to illustrate the flow divider;

Fig. IB illustrates the temporary storage space in a cross section taken along the line A-A

Fig. 2A is a partially sectioned side view of a portion of a discharge chute containing the storage space illustrated in fig. 1 , with the flow divider illustrated in its inactive retracted position prior to emptying;

Fig. 2B is a side view corresponding to fig. 2A, illustrating the flow divider extended to its active position immediately prior to emptying;

Fig. 2C is a side view corresponding to fig. 2A, illustrating the extended flow divider during emptying;

Fig. 3 illustrates a second embodiment of a temporary storage space according to the invention, in a cross section similar to that of fig. IB;

Fig. 4A illustrates a third embodiment of a temporary storage space according to the invention, in a cross section similar to that of fig. IB; Fig. 4B illustrates the flow divider of the temporary storage space of fig. 4A, in a cross section taken along the line B-B in fig. 4A;

Fig. 5 illustrates a fourth embodiment of a temporary storage space and flow divider according to the invention, in a partial longitudinal section; and

Fig. 6 illustrates a fifth embodiment of a temporary storage space and flow divider according to the invention, in a partial longitudinal section similar to that of fig. 5.

DETAILED DESCRIPTION OF EMBODIMENTS

The basic principles of the invention shall now be described by means of a first embodiment thereof, illustrated in figs. 1A-B and 2A-C. In fig. 1 A is illustrated a lower portion of an injection chute 12 of a stationary vacuum refuse collection system 10. Said chute 12 has closeable inlets or insertion openings 4 (one is schematically illustrated in figs. 2A-C) on each story of a building 6, 7 that is likewise schematically illustrated in figs. 2A-C. Through the openings 4, refuse or waste may be inserted into the chute 12. At its lower end, the chute 12 is connected to an underground transport pipe 11 through a discharge valve 2. The discharge valve 2 is opened and closed at regular or controlled intervals for emptying the chute 12. Refuse that is introduced into the transport pipe 11 by opening the discharge valve 2 is conveyed by means of subatmospheric pressure through the transport pipe 11 and into a container that is normally arranged in a collecting central that will not be illustrated or described in detail herein. However, for further details regarding the general design of such a system, reference can be made i.e. to our earlier Swedish Patent Application 0102249-0.

In such a system 10 that is schematically illustrated in figs. 2A-C, the lowermost portion of the chute 12, situated immediately upstream of a discharge valve 2, is employed as a temporary storage space 1 for refuse 9. In other words, refuse that is inserted into the chute 12 during the time between the emptying phases of the chute 12, is accumulated above the discharge valve 2 and is temporarily stored in said space 1.

In line with the above mentioned presently increasing demand for recycling, chutes 12 of this kind of collection systems 10 are also being used for collecting different fractions of refuse 9. This is done either by installing separate chutes 12 for different fractions or by collecting different fractions at separate times, such as on separate days of the week, in one and the same chute 12.

To enhance the emptying of chutes 12 wherein a paper fraction is collected, a single flow divider 3 - the advantageous effect of which will be discussed further below - is provided in the storage space 1 above the discharge valve 2. In the illustrated embodiment the flow divider consists of a piston rod 3 of a fluid cylinder 5 that is attached to the wall 1 A of the storage space 1, in this embodiment equal to the wall of the actual chute 12. The fluid cylinder 5 is attached to the chute wall 1A in any appropriate way, such as by means of the schematically illustrated bolts 5B and fixed end plate 5 A (fig. 1A). The piston rod/flow divider 3 is extendable and retractable through an opening IB in the wall 1A.

In view of the above, it is clear that the flow divider 3 is supported by the wall 1 A outside the storage space 1 and is extendable in a linear movement through the wall 1A and into the storage space 1. The fluid cylinder 5 and thereby the flow divider 3 are arranged substantially horizontally. More specifically, in the illustrated embodiment the flow divider 3 is arranged to be extendable and retractable in a direction L being generally transversal to a direction of flow F through the vertical storage space 1.

The temporary storage space 1 is illustrated having a circular cross section (fig. IB). In such an embodiment the flow divider 3 is preferably extendable and retractable in the direction L being substantially perpendicular to a centre line C of the storage space 1 and essentially coinciding with a diameter D of the storage space 1. In figs. 1A and IB, the flow divider 3 is illustrated in its extended position with an outer free end 3 A thereof being spaced from the wall 1A of the storage space 1. However, the invention is not restricted to the illustrated positioning of the free end 3 A of the flow divider 3, or specifically to its illustrated spacing from the wall 1A in the extended condition. Depending upon the conditions of the specific application the length of the flow divider 3 or the degree of extension thereof may be varied. Presently, it is regarded that for the paper fraction the best effect is achieved when the flow divider 3 in its extended position spans at least half of the diameter D of the storage space 1, and preferably spans between 60% and 95%, even more preferably between 80% and 90%, of the diameter. However, the exact portion of the diameter of the storage space 1 that the flow divider 3 spans in its extended position will be determined for each specific case, based on factors such as the amount of paper normally accumulated in a chute prior to emptying, the geometry of the storage space and/or the composition of the collected fraction.

1. The purpose of the flow divider 3 is to loosen up the flow of the paper fraction 9 by dividing the flow during emptying, and it shall not block the flow or any portion thereof, as will be discussed further below. In order to secure this, the flow divider 3 shall be designed to occupy only a limited portion of the cross section of the storage space 1 when in its extended position. In the illustrated embodiment where the flow divider 3 is a piston rod of a fluid cylinder 5, the flow divider 3 occupies a very small portion of the cross section of the storage space 1. Since the single flow divider in its extended position projects into the storage space approximately through a centre line C thereof, the paper fraction will be properly divided, without risking any blocking of the flow.

The operation of the flow divider 3 will now be described with specific reference to figs. 2A- C. Fig. 2A illustrates the situation during insertion of paper 9 into the chute 12 through the insertion openings 4 and accumulation thereof in the storage space 1. During the major part of this accumulation phase, the flow divider 3 is in its retracted position in the cylinder 5, withdrawn from the storage space 1. The main reason for maintaining the flow divider 3 in its retracted position during substantially the full accumulation phase, is to protect the flow divider 3 from bundles of paper 9 that may fall from great height, such as in high rise buildings. For the same reason, the flow divider 3 will be retracted so that it is completely withdrawn from the storage space 1 during accumulation.

It should be emphasized though, that in its broadest scope the invention also covers embodiments where the flow divider remains in its extended position during the accumulation phase. Such an alternative procedure will not impede the effectiveness of the flow divider 3, but will require a flow divider of a very high strength design in order to withstand the impacts from paper bundles. Such a design will in most cases not be considered due to the considerably increased costs for the high strength design. The flow divider 3 is then extended in the direction E (fig. 2A) in connection with, and preferably just prior to, opening the discharge valve 2 for the emptying phase, see fig. 2B-C. As was mentioned above, opening of the discharge valve 2 will initiate emptying of the storage space 1 by means of the vacuum of the system 10. As the system vacuum is communicated to the storage space 1 and transport air S is supplied, normally through the chute 12 as well as by the discharge valve 2, the accumulated paper 9 is forcefully sucked into the transport pipe 11. In this situation the extended flow divider 3 will have the advantageous effect of dividing the flow of paper 9 to thereby loosen up the accumulated volume of paper by mixing in air in said volume. It is important to emphasize that in this manner the flow of paper 9 is not blocked, but the actual emptying phase is prolonged. By making the paper volume or accumulated body of paper 9 less compact or "looser", the body of paper will be securely emptied without the risk of any blockage or formation of plugs, as is otherwise common when using the conventional techniques. As indicated above, the looser body of paper 9 achieved by means of the invention, will have an increased length and will therefore take slightly longer to discharge from the storage space 1. To exemplify this, the use of the flow divider 3 of the invention has under certain test conditions prolonged an ordinary emptying time of 2-3 seconds (without flow divider) to 5-6 seconds (with extended flow divider).

At the end of the emptying phase, the flow divider 3 is retracted in the direction R (fig. 2A) before the discharge valve 2 is closed. In this way, it is secured that no paper 9 has got stuck on the actual flow divider 3 or between the flow divider 3 and the wall 1A. As soon as the discharge valve 2 has been closed, the chute 12 and the storage space 1 are ready for the next accumulation phase. Normally the flow divider 3 will remain in the retracted position until shortly before the next emptying phase, as was discussed above.

In summary, the provision and operation of the inventive flow divider 3 will secure reliable emptying of the accumulated paper fraction 9, without the risk of blockage and plug formation. The capacity of the storage space 1 is not negatively affected since the discharge of the volume of paper is not blocked, but is only partly delayed in the meaning that the discharge of a specified volume of the fraction is distributed over a slightly longer time. In effect, the use of the invention has the opposite effect, by allowing accumulation of a larger volume of the fraction in the storage space without endangering a secure discharge or emptying. Furthermore, it shall be emphasized that the illustrated distance between the flow divider 3 and the discharge valve 2 as well as the specific design of the illustrated temporary storage space and flow divider, with regard to its shape and length, is only intended to exemplify the invention. In practice such specifications will be chosen based on the conditions of each specific application, such as the geometry of the chute, the expected composition of the collected paper fraction and the design as well as operational parameters of the entire collection system.

Examples of such alternative embodiments that fall within the scope of this invention are illustrated in figs. 3-6. In fig. 3 is illustrated a flow divider 3 and fluid cylinder 5 corre- sponding to those of the first embodiment, but attached to a temporary storage space 101 of a square shape. In this case, the flow divider 3 is extended through a first wall 101 A of the space 101, through the centre line C and towards an opposite wall 101B thereof. This is to exemplify that the principles of the invention may be applied to almost any storage space, irrespective of its cross section shape being circular, square, rectangular or other.

Figs. 4A-B illustrate an alternative embodiment of the flow divider 203 having a triangular cross section. One corner 204 of the triangular shape forms a relatively sharp point and is directed upwardly, opposing the flow direction F in the storage space 1, see fig. 1A. With such a configuration, the flow divider 203 will be strong, withstanding higher impact, but will still perform an excellent division of the flow, without any danger of blocking flow. In the illustrated embodiment the flow divider 203 is attached to the circular storage space of figs. 1A-B, and is likewise extendable and retractable through the wall 1A of the space 1. However, in this embodiment the flow divider 203 does not constitute a piston rod of a cylinder, but is schematically illustrated as being moveably guided and supported on a kind of guide 205 attached to the exterior of the wall 1A. The manner of extending and retracting the flow divider is not specified, but may be performed in any appropriate manner, such as by means of separate fluid motors, a chain drive, a rack and pinion drive or any other suitable mechanical drive means. This is to exemplify that the invention in its broadest scope covers a great variety of different designs of the actual flow divider, having the common feature of not blocking but dividing and distributing the flow of the fraction during discharge thereof. Fig. 5 illustrates a further embodiment of a flow divider 303 being pivotally attached to the interior of the wall 1A of a storage space 1 corresponding to that of figs. 1A-B. In this embodiment the flow divider 303 is pivotal between a retracted position in which it is extended downwards along the inner side of the wall 1A, and an extended position in which it is extended generally transversal to the flow direction, see fig 1 A. The drive means 305, 306 for performing the pivotal motion is only illustrated very schematically, but may preferably consist of an electric, or alternatively hydraulic, drive motor 305 operating the flow divider 303 through a transmission 306, such as a gear mechanism. Finally, fig. 6 illustrates a variant of the embodiment according to fig. 5, employing similar drive means and a modified but likewise pivotally operated flow divider 403. In this case, the flow divider 403 is pivotal between a retracted position extended upwards along the inner side of the wall 1A and the extended, generally transversal position. Furthermore, the flow divider 403 has a length being only slightly shorter than the diameter D (see fig. IB) of the storage space 1. Therefore, in the extended position of the flow divider 403 the free end 403 A thereof is positioned close to the wall 1 A of the storage space 1. In other words, in the extended position the flow divider spans the major portion of the storage space. To increase the stability and strength of the flow divider 403 so that it may even be maintained in the extended position during the accumulation phase, a support block 407 is provided on the interior of the wall 1A. In its extended position, the free end 403A of the flow divider 403 will be supported on said block 407.

Throughout this description, the invention has been discussed in connection with collecting a paper fraction. Although the invention is presently regarded to have its main area of application for this specific fraction, it should be emphasized that the scope of the invention shall not be limited thereby. On the contrary, the invention will be applicable to the collection of other refuse fractions having essentially similar flow characteristics as the paper fraction.

Furthermore, the invention has been described above with reference to the drawing figures that illustrate embodiments thereof adapted for use in specific types of temporary storage spaces of vacuum collection systems inside buildings. However, it shall be understood that the invention is not restricted to these exemplifying embodiments or to the specific applications described above. The basic principles of the invention may likewise be applied in association with other refuse collection systems having other types of storage spaces, like the type of individual separate insertion chutes that may be connected to the same transport pipe 11 as the illustrated multi- storage chute 12 or to separate branches thereof, not illustrated. Such separate insertion chutes may be employed in different applications, such as a free standing chute positioned outdoors or a likewise free standing chute being positioned for instance on the ground floor of a larger public building complex, such as a maul, a sports arena etc. Likewise, the invention is applicable to temporary storage spaces that are not formed by the actual chute, but by a separate, in some cases expanded, storage space.

It will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departure from the scope thereof, which is defined by the appended claims.

Claims

PATENT CLAIMS

1. A method of controlling the discharge of an accumulated paper fraction from a temporary storage space (1; 101) upstream of a discharge valve (2) in a vacuum refuse collection system (10), said discharge being initiated by opening the discharge valve to communicate a vacuum of the system (10) with the storage space (1; 101), characterized in that during discharge thereof the flow of the paper fraction is divided upstream of the discharge valve, to thereby loosen the accumulated paper fraction (9) and secure unblocked discharge thereof.

2. A method according to claim 1, characterized in that the flow of the accumulated paper fraction (9) is mechanically divided without any blocking thereof.

3. A method according to claims 1 or 2, characterized in that prior to opening the discharge valve (2) a single flow divider (3; 203; 303; 403) is extended into the storage space at a position upstream of the discharge valve.

4. A method according to claim 3, characterized in that the flow divider (3; 203; 303; 403) is extended into the storage space (1; 101) approximately through a centre line (C) thereof.

5. A method according to claim 3 or 4, characterized in that the flow divider (3; 203) is extended into the storage space (1; 101) in a linear movement through a wall (1A) or a first wall (101 A), respectively, of the storage space and in a direction (E) being transversal to, preferably being approximately perpendicular to, a general direction of flow (F) through the storage space.

6. A method according to any of claims 3-5, characterized in that the flow divider (3; 203) is extended into the storage space (1) along a line (L) approximately coinciding with a diameter (D) of a storage space having a substantially circular cross section.

7. A method according to any of claims 3-6, characterized in that the flow divider (3; 203) is linearly extended and retracted, respectively, between positions being completely retracted from the storage space (1; 101) and being extended at least across a major portion of the cross section of the storage space.

8. A method according to any of claims 3-7, characterized in that the flow divider (3; 203; 303; 403) is extended into the storage space (1; 101) to a position where a free end (3A; 403A) thereof is spaced from the wall (1A) or a second wall (10 IB), respectively, of the storage space

9. A method according to claim 8, characterized in that the flow divider (3; 203; 303; 403) is extended into the storage space (1 ; 101) to a position where the free end (3 A; 403 A) thereof is positioned between the centre line (C) of the storage space and the wall (1A) or a second wall (10 IB), respectively, of the storage space (1; 101).

10. A method according to any of claims 3-9, characterized in that by extending the flow divider (3; 203; 303; 403) only a restricted portion of the cross section of the storage space (1; 101) is blocked, thereby allowing paper stored above the position of the flow divider to pass the flow divider in its extended position.

11. A method according to any of claims 3-10, characterized in that the flow divider (3; 203; 303; 403) is retracted from the storage space (1; 101) after opening the discharge valve (2) but prior to closing the valve subsequent to emptying the storage space.

12. A temporary storage space (1 ; 101) of a vacuum refuse collection system (10), said storage space communicating at one end with a refuse inlet (4) and at another end with the refuse collection system through a discharge valve (2), characterized in that a single flow divider (3; 203; 303; 403) is attached to a wall (1A) or a first wall (101A), respectively, of the storage space (1; 101) and in that the flow divider is extendable into the storage space and retractable therefrom, respectively, to secure unblocked discharge of an accumulated paper fraction (9) from the storage space, when in its extended position.

13. A temporary storage space (1; 101) according to claim 12, characterized in that the single flow divider (3; 203; 303; 403) in its extended position projects into the storage space approxi- mately through a centre line (C) thereof.

14. A temporary storage space (1; 101) according to claim 12 or 13, characterized in that the flow divider (3; 203) is supported by the wall (1A) or the first wall (101A), respectively, outside the storage space (1 ; 101) and is extendable through the wall (1A) or the first wall (101 A), respectively, and into the storage space (1; 101) in a linear movement.

15. A temporary storage space (1; 101) according to any of claims 12-14, characterized in that the flow divider (3) is a rod of a fluid operated cylinder (5) being attached to the wall (1A) or the first wall (101 A), respectively, of the storage space (1; 101).

16. A temporary storage space (1; 101) according to any of claims 12-15, characterized in that the flow divider (3; 203) is arranged to be extendable and retractable in a direction (L) being generally transversal to a general direction of flow (F) through the storage space (1; 101).

17. A temporary storage space (1; 101) according to any of claims 12-16, characterized in that the flow divider (3; 203) is arranged to be extendable and retractable in a direction (L) being substantially perpendicular to a centre line (C) of the storage space (1; 101).

18. A temporary storage space (1) according to claim 17, having a substantially circular cross section, being surrounded by a cylindrical wall (1A), characterized in that the flow divider (3; 203) is arranged to be extendable and retractable in a direction (L) essentially coinciding with a diameter (D) of the storage space.

19. A temporary storage space (1; 101) according to any of claims 12-18, characterized in that in its extended position an outer end (3A; 403A) of the flow divider (3; 203; 303; 403) is spaced from the wall (1A) or the first wall (101 A), respectively, of the storage space.

20. A temporary storage space (1; 101) according to any of claims 12-19, characterized in that in its extended position the flow divider (3; 203; 303; 403) occupies only a small portion of the cross section of the storage space.

21. A temporary storage space (1) according to any of claims 12-20, being a lower portion of a stationary refuse insertion chute (12) of the refuse collection system (10), characterized in that the flow divider (3; 203) is arranged substantially horizontally.