WO2012117146A1

WO2012117146A1 - Method and apparatus for achieving an air flow in a refuse chute

Info

Publication number: WO2012117146A1
Application number: PCT/FI2011/050172
Authority: WO
Inventors: Göran Sundholm
Original assignee: Maricap Oy
Priority date: 2011-02-28
Filing date: 2011-02-28
Publication date: 2012-09-07
Also published as: CN103380067A; SG192240A1

Abstract

Method for achieving an air flow in a refuse chute (1), which refuse chute comprises at least one input aperture (4) of waste material, in which method the waste material (5) fed into the refuse chute from an input aperture (4) is moved in the refuse chute under the effect of gravity to the bottom part of the refuse chute. An opposing air flow with respect to the direction of travel of the waste material (5) is achieved in the refuse chute (1) using at least one partial -vacuum generator for conveying of the wastes in a pneumatic waste conveying system. The invention also relates to an apparatus.

Description

METHOD AND APPARATUS FOR ACHIEVING AN AIR FLOW IN A REFUSE CHUTE

Background of the invention

The object of the invention is a method as defined in the preamble of claim 1.

The object of the invention is also an apparatus as defined in the preamble of claim 10.

The invention relates generally to material conveying systems, such as to partial- vacuum conveying systems, more particularly to the collection and conveying of wastes, such as to the conveying of household wastes. The invention also relates to refuse chutes, with which waste is typically moved by gravity, e.g. from upper input apertures in residential apartments to a lower collection space or corresponding.

Systems wherein wastes are conveyed in piping by means of a pressure difference or suction are also known in the art. In these, wastes are conveyed long distances in the piping by sucking. It is typical to these systems that a partial- vacuum apparatus is used to achieve a pressure difference, in which apparatus a partial vacuum is achieved in the conveying pipe with partial-vacuum generators, such as with vacuum pumps or with an ejector apparatus. A conveying pipe typically comprises at least one valve means, by opening and closing which the replacement air coming into the conveying pipe is adjusted. Refuse chutes are used in the systems at the material input end, into which refuse chutes material, such as waste material, is fed in and from which refuse chutes the material to be conveyed is transferred into a conveying pipe by opening a discharge valve means, in which case, by means of the sucking effect achieved by the aid of the partial vacuum acting in the conveying pipe and also by means of the surrounding air pressure acting via the refuse chute, material such as e.g. waste material packed into bags, is conveyed from the refuse chute into the conveying pipe. The pneumatic waste conveying systems in question can be utilized particularly well in densely populated urban areas. These types of areas have tall buildings, in which the input of wastes into a pneumatic waste conveying system is performed via a refuse chute arranged in the building. A refuse chute is a vertical pipe comprising a number of input points, which are typically arranged in the wall of the refuse chute at a distance from each other. Tall buildings can comprise many tens, even hundreds, of storeys, in which case the refuse chute forms a very high pipe. In this case waste, e.g. in bags, to be fed into the refuse chute from above falls a long distance in the chute, e.g. up to 200 m, in which case the speed of the waste material accelerates to be very high as it falls downwards in the refuse chute. Freely falling waste material is smashed in the bottom part of the refuse chute. One problem can be that the waste that has fallen at a high speed into the bottom part of the refuse chute and smashed, and which waste is tightly compacted in the bottom part of the chute, does not always move into the conveying piping from the bottom part of the refuse chute. When the waste material has become compacted onto the bottom of the refuse chute, near the output aperture, one problem is that the material that has compacted in the proximity of the output aperture might block the output aperture, in which case conveying of the material from the refuse chute into the conveying pipe is prevented and/or the access of replacement air from the refuse chute into the conveying pipe is prevented. Attempts have been made to prevent compacting of the waste material by arranging mechanical obstacles in the chute, by means of which it is endeavored to slow down the falling speed of waste bags in the refuse chute. A problem with mechanical deceleration obstacles is that the waste bags often break when they hit them, in which case the wastes make the inside surface of the refuse chute unnecessarily dirty. This makes keeping the refuse chute clean more difficult and, in addition, the wastes from broken waste bags that have made the refuse chute dirty create odor nuisances. In addition, the collision of waste material with an obstacle creates noise nuisances. Additionally, possible intermediate tanks of wastes to be used in connection with the system can cause odor nuisances.

The aim of the present invention is to achieve a new type of solution in connection with refuse chutes, by means of which solution the drawbacks of prior art solutions are avoided.

Brief description of the invention

The invention is based on a concept wherein an opposing air flow with respect to the direction of travel of the waste material is achieved in a refuse chute with at least one partial-vacuum generator to be used for the conveying of the wastes of a pneumatic waste conveying system.

The method according to the invention is mainly characterized by what is disclosed in claim 1.

The method according to the invention is also characterized by what is stated in claims 2 - 9. The apparatus according to the invention is mainly characterized in that the apparatus comprises means for achieving an opposing air flow with respect to the direction of travel of the waste material in the refuse chute with at least one partial- vacuum generator to be used for the conveying of the wastes of a pneumatic waste conveying system.

The apparatus according to the invention is also characterized by what is stated in claims 11 - 18.

The solution according to the invention has a number of important advantages. According to the invention a partial-vacuum generator to be used in the conveying of wastes can be used to achieve an opposing air flow to the conveying direction of the wastes in the refuse chute. In this case a separate pump apparatus is not needed for achieving an opposing air flow in the refuse chute. The invention can be implemented by arranging a medium pathway from the top part of the refuse chute to the pump devices, either directly or e.g. via one or more intermediate tanks of the wastes. With this arrangement odor nuisances possibly caused by the wastes in an intermediate tank of wastes in the immediate proximity of them can also be reduced and can be conducted with the air circulation to e.g. the location point of the partial-vacuum generators. In one embodiment a conveying pipe of wastes forms a part of the medium pathway. According to the embodiment of the invention the valve means needed for opening/closing the air circulation at least to the medium pathway are arranged between the top part of the refuse chute and the conveying pipe, in which case the passage of air in the medium pathway can be arranged in the different phases of the operating cycle of conveying wastes. By means of the invention fast and effective emptying of the refuse chute into the conveying pipe is achieved. With the method and apparatus according to the invention it is possible to slow down in a controlled manner the falling speed of waste material in the refuse chute. At the same time it is possible to reduce the susceptibility to clogging of the output aperture of the refuse chute, in which case the operation of the pneumatic material conveying system remains good. Another significant advantage is the conducting of the particles and odors of the refuse chute out of the refuse chute along with the air flow, in which case inconvenience due to odors can be substantially reduced. According to the invention material refuse chutes, which are the input points of waste, can be used, such as waste receptacles or refuse chutes. The method and apparatus according to the invention are particularly well suited in connection with conveying systems of waste material, such as waste material arranged in bags. A pump device always produces a small air flow in the non-active state in normal operation, with which air flow the development of odors, gases and also small particles in the chute is prevented, in which case the fire hazard and explosion hazard are reduced. The air flow achieved by the pump device is boosted when the hatch of the input aperture is opened or waste bags are otherwise allowed into the chute. A delay of the desired length can be used in connection with boosting the air flow and with opening/closing the hatch. A material space, i.e. an input pocket, can be in connection with the input apertures, the emptying of which space is typically performed from the bottom upwards so that the initiation of clogging in the chute is prevented. .

The air flow can also be arranged such that at first the air flow lifts the waste material upwards in the refuse chute and after that the air flow is regulated, e.g. by reducing the amount of air in a controlled manner such that the waste material descends at the desired speed downwards to the material space. This arrangement is preferably achieved with an air ejector, wherein air is taken from an accumulator, the pressure of which decreases during the emptying cycle.

One advantage of an air ejector is also that air is added to the exhaust, in which case there are fewer microparticles per unit. Brief description of the figures

In the following, the invention will be described in more detail by the aid of an example of its embodiment with reference to the attached drawings, wherein

Fig. 1 presents one simplified embodiment of an apparatus according to the invention, in a first operating phase, Fig. 2 presents one simplified embodiment of an apparatus according to the invention, in a second operating phase,

Fig. 3 presents one simplified embodiment of an apparatus according to the invention, in a third operating phase,

Fig. 4 presents one simplified embodiment of an apparatus according to the invention, in a fourth operating phase,

Fig. 5 presents as a diagram one embodiment of an apparatus according to the invention in connection with a waste conveying system,

Fig. 6 presents a detail of an apparatus according to the invention, in a first position, and Fig. 7 presents a detail of an apparatus according to the invention, in a second position.

Detailed description of the invention Figs. 1 - 4 present as a simplified diagram one embodiment of the solution according to the invention. The figures present in more detail a part of a system comprising one refuse chute. Fig. 5, for its part, presents a simplified pneumatic waste conveying system comprising four refuse chutes 1 as an entity with its partial-vacuum generators 300A, 300B, 300C, 300D and conveying piping 100A, 100B and separating means 200, 201 , 202. Figs. 1 - 4 present the operation in different phases in respect of one refuse chute of Fig. 5. The refuse chute 1 of the pneumatic material conveying system is in Fig. 1. The refuse chute 1 extends in the vertical direction e.g. through the floors of a building, in which case the top end 2 of the refuse chute extends e.g. to the top floor or even to the roof of a building. The bottom end 3 of the refuse chute 1 extends to an intermediate tank 9 and/or to conveying piping 10 in the bottom part of the building, e.g. in the basement. One or more input apertures 4 are arranged in the refuse chute 1. The refuse chute 1 in the figure is a section of pipe that is arranged in a suitable location e.g. in a building.

Material is fed into the refuse chute 1 via one or more input apertures 4. A hatch arrangement 7 or similar can be in connection with the input aperture 4. Additionally, a valve means V, with which access of material into the refuse chute 1 is adjusted, can be in connection with the input aperture. The hatch arrangement and valve arrangement according to one embodiment, and in connection with the input aperture, is described in more detail below and presented in Figs. 6 and 7. Typically waste material 5 is dropped from the input aperture 4 into the refuse chute 1. A number of input apertures 4 are arranged in the refuse chute, typically at least one for each floor of the building.

The refuse chute 1 is connected from its bottom part 3 directly, or as in Fig. 1 via a material space 6, to an intermediate tank 9. A discharge valve 8, which is driven with a drive device (M), is between the intermediate tank 9 and the material space 6 of the bottom part 3 of the refuse chute 1. In the embodiment of Fig. 1 , the bottom part 3 of the refuse chute therefore comprises a material space 6, which is bounded by walls, into which material space the waste material 5, such as waste packed into bags, falls, typically under the effect of gravity.

The material 5 that is fed from an input aperture 4 into the refuse chute 1 tries to compact under the effect of gravity into the bottom part 3 of the refuse chute 1 , against the walls of the material space 6 of the bottom part and against the discharge valve 8 of the output aperture. In a conventional arrangement there is a risk of clogging of the output aperture of the refuse chute and in pneumatic systems a risk of prevention of the access of replacement air that is essential from the viewpoint of operation in the discharge phase of the container. To avoid the drawbacks of prior art the means 14, 16, 17, 18, 19, 21 in the embodiment of Figs. 1-5 are arranged in connection with the refuse chute, for producing an opposing air flow with respect to the conveying direction of the material 5 in the refuse chute 1. Apart from removing and conducting the odors of a refuse chute by means of an air flow, an air flow can also be used for slowing down the falling speed of the waste material 5 in the refuse chute 1. The devices comprise at least one partial-vacuum generator 300A...300D to be used for conveying the material of a pneumatic material conveying system, the suction side of which partial-vacuum generator can be connected to the top end 2 of the refuse chute 1 via, inter alia, the material conveying piping 100A, 100B, 10 and a medium channel 14 that is external to the refuse chute.

When the waste material 5 is fed into the refuse chute, an opposing air flow with respect to the direction of movement of the waste material is achieved in the refuse chute 1 , which air flow is presented in Fig. 1 with arrows pointing upwards in the refuse chute 1 , i.e. towards the first end 3 of the refuse chute. In order to achieve the air flow, replacement air is needed in the refuse chute, which replacement air is received in Figs. 1 - 4 from a replacement air aperture 15 formed in the refuse chute , preferably in the proximity of the bottom part 3 of it.

In the case of Fig. 1 the air flow acts in the refuse chute against the falling direction of an object, more particularly of waste material, such that the falling speed of the waste material 5, more particularly of the waste material packed in a bag, remains most suitably such that the waste material does not compact into the bottom part of the refuse chute too densely and, on the other hand, such that the waste bags remain intact from the fall and do not disintegrate.

In Fig. 1 the movement of the replacement air from the replacement air duct 15 between the bottom part 3 of the refuse chute and the end of the top part of the material space 6 and onwards in the refuse chute 1 against the falling direction of _^the waste material is presented with arrows. Movement of the replacement air is achieved by means of the partial vacuum/suction achieved in the conveying pipe 10 by the partial-vacuum generators of the conveying system, which partial vacuum/suction acts via the medium conveying channels 21 , 17 in the intermediate tank 9 and onwards in the medium conveying channel 14, which is connected to the top part 2 of the refuse chute 1. In Fig. 1 waste material 5 is fed into the refuse chute from one input aperture 4 of the refuse chute 1 by opening the hatch 7. The waste material 5 drops towards the bottom end 3 of the chute under the effect of gravity. An opposing air flow is achieved with the partial-vacuum generators 300A, 300B, 300C, 300D of the material conveying system, slowing down the falling of the waste material in the refuse chute 1. With the partial-vacuum generators a speed of upward moving air is achieved in the refuse chute that is sufficient to slow down the downward-falling waste material, such as a waste bag. With the partial-vacuum generators a small suction can be achieved in the refuse chute in the normal state, which suction removes odor from the refuse chute and from the intermediate tank 9. When the hatch 7 of the input aperture 4 of a certain floor is opened, the suction achieved by the partial-vacuum generators is fitted to the preprogrammed level required by the floor in question, which level essentially prevents the movement of the bag from accelerating downwards.

Fig. 2 presents, for its part, the apparatus according to the embodiment of Fig. 1 in a second operating phase, in which the waste material that has collected in the material space 6 in the bottom part of the refuse chute 1 is conveyed to an intermediate tank 9 of a pneumatic waste conveying system, in a manner that is in itself prior art, by opening the valve 8, in which case the material is able to move into the intermediate tank 9 from the effect of the pressure difference. Fig. 2, for its part, presents a situation in which the waste material that has collected in the material space 6 of the bottom part 3 of the refuse chute 1 is emptied into the intermediate tank 9. The valve 16 in the medium pathway 14 is closed, in which case an essentially opposing air flow with respect to the conveying direction of the material does not act in the refuse chute 1. In the embodiment of the invention suction/partial vacuum acts in the conveying pipe 10, in which case there is a medium connection open from the conveying pipe 10 along the medium pathway 21 , 17 into the top part of the intermediate tank 9. The replacement air duct 15 is open, in which case suction/pressure difference, together with gravity, when the valve 8 between the material space 6 and the intermediate tank is open, achieve conveyance of the material 5 from the material space 6 of the bottom part of the refuse chute onwards into the intermediate tank 9 or directly into the conveying pipe 10 (if there is no intermediate tank). In the embodiment of the figure the intermediate tank 9 comprises a worm conveyor 11 , with which material can be fed towards the output aperture. In the embodiments of the figures a rotary shaper (formatter) of the material is arranged in connection with an output aperture, which rotary shaper shapes/compresses the material into a size of smaller diameter to fit into the conveying pipe 10 and onwards into the main conveying pipe 100A, 100B.

Fig. 3 presents a situation in which material is conveyed from the intermediate tank 9 into the conveying pipe when the discharge valve 13 is opened, in which case the material 5 can be conveyed into the conveying pipe 10. In this operating phase the valve 8 between the material space 6 of the refuse chute and the intermediate tank 9 can be closed and the valve 16 in the medium pathway 14 can be opened. In this case an opposing air flow to the material conveying direction again acts in the refuse chute 1 and replacement air is received into the intermediate tank via the medium pathway 14, e.g. from the replacement air duct 15 of the refuse chute. According to Fig. 3 the valve 19 of the medium pathway 17 leading from the conveying pipe 10 to the top part of the intermediate tank 9 is closed.

There can be a number of partial-vacuum generators 300A, 300B, 300C, 300D. In Fig. 5 for the sake of clarity only a part of the components of the partial-vacuum generators 300A, 300B, 300C, 300D are provided with reference numbers. The pump device 301A of the first partial-vacuum generator 300A is driven with a drive device 302A. A regulating device, e.g. for regulating the speed of rotation of the pump, can be in connection with the drive device and/or the pump device. With the devices an air flow is produced in the refuse chute 1 in the opposite direction with respect to the falling direction of the waste material 5. In the embodiment of Fig. 5, there is at least one separating device 200, 201 , 202 between the partial-vacuum generators 300A, 300B, 300C, 300D and the refuse chute 1 , typically also a filtering device, and a noise muffler in the exhaust line 113 on the blowing side of the pump. The suction side of a partial-vacuum generator 300A, 300B, 300C, 300D can be connected via a valve 0A...1 0D to the pipeline 109, which in the embodiment of the figure leads via one or more separating means 200, 201 , 202 to the conveying piping 100A, 100B of material. According to the basic operation of a pneumatic pipe conveying system of material, material is fed from input points, such as from the input apertures 4 of refuse chutes 1 in the embodiment of Fig. 5, into a system in which the material 5 is conducted either directly, or via an intermediate tank 9 as in the embodiment of the figures, into a conveying pipe 10, 100A, 100B, by the aid of the partial vacuum/pressure difference achieved by one or more partial-vacuum generators 300A, 300B, 300C, 300D, and/or by the aid of the movement of conveying air along the conveying piping (either the conveying pipe 100A or the conveying pipe 100B) into a separating means 200, 201 , 202, where the material to be conveyed separates from the conveying air, e.g. by the aid of centrifugal force and gravity. The separating means is typically a so-called eddy current separator, in which heavier material drops to the bottom part of the separator and the conveying air is conducted out from the top part of the separator. The separating means 200, 201 is emptied from time to time, e.g. into a container below the separating means, which container can also comprise a press. There can be a number of separating means, e.g. two as in the embodiment of Fig. 5, in which case the material to be conveyed in the piping can be conducted by means of the valves 102, 103 and the pipelines to either one of the separating means 200, 201 whatsoever. It can also be conceived that the material to be conveyed is conducted from the pipe 100A to one separating means, e.g. to the separating means 200, and from the pipeline 100B to the second separating means 201. Downstream from the separating means in the conveying direction of the conveying air can be one or more dust separators 202 and/or a filtering means.

The conveying air can be blown out via the exhaust line 113 or a part of the conveying air can be circulated back into the conveying piping if it is connected into a circuit.

The pneumatic conveying system of waste material according to Fig. 5 is additionally one in which the conveying air can be circulated in the conveying piping 100A, 1Ό0Β when the valve 101 is opened. In this case the blowing side of at least one partial-vacuum generator 300A...300D is connected to blow into the circuit by opening the valve 111 A...111 D and by conducting the air of the blowing side along the pipeline 114 to either one of the pipes 117 or 118, the connection to which is adjusted by means of the valves 115, 116. If it is desired to blow into the circuit e.g. on the side of section 110B of the conveying pipe, the valve 115 in the pipe 117 is opened. In order for the air to circulate in the conveying pipe 100A, 100B, the valve 101 must be opened and correspondingly the return side of the pipe 100A must be connected to the suction side of a partial-vacuum generator. This can be done by opening the three-way valve 103 to either one of the separator means 200, 201 , i.e. to the pipeline 105 or 104 and the medium pathway from the top part 107 or 106 of the separator means onwards to the second separator means and from there into the pipeline 109 that goes to the partial- vacuum generators.

The replacement air duct 22 can also be opened by opening the valve 20 in the medium pathway 21 , in which case replacement air that enhances the conveying of material is obtained in the conveying pipe 10. According to certain preferred embodiments:

• The pump device always produces a small air flow in the non-active state in normal operation, with which air flow the development of odors, gases and small particles in the chute are prevented. Fire hazard and explosion hazard.

· The air flow achieved by the pump device is boosted when the hatch of the input aperture is opened or waste bags are otherwise allowed into the chute. A delay of the desired length can be used in connection with boosting the air flow and with opening/closing the hatch.

• A material space, i.e. an input pocket, can be in connection with the input apertures, the emptying of which space is typically performed from the bottom upwards so that the initiation of clogging in the chute is prevented.

• The air flow can also be arranged such that at first the air flow lifts the waste material upwards in the refuse chute and after that the air flow is adjusted, e.g. by reducing the amount of air in a controlled manner, such that the waste material descends at the desired speed downwards to the material space 6. This arrangement is preferably achieved with an air ejector, wherein air is taken from an accumulator, the pressure of which decreases during the emptying cycle.

• One advantage of an air ejector is also that air is added to the exhaust, in which case there are fewer microparticles per unit.

Typically the material 5 is waste material, such as waste material arranged in bags. The refuse chute can be fitted to be a part of a pneumatic waste conveying system or it can be a separate part, in which waste material is conducted into the waste room, waste container or corresponding. The invention thus relates to a method for achieving an air flow in a refuse chute 1 , which refuse chute comprises at least one input aperture 4 of waste material, in which method the waste material 5 fed into the refuse chute from an input aperture 4 is moved in the refuse chute under the effect of gravity to the bottom part of the refuse chute. An opposing air flow with respect to the direction of travel of the waste material 5 is achieved in the refuse chute 1 with at least one partial-vacuum generator 300A, 300B, 300C, 300D to be used for the conveying of the wastes of a pneumatic waste conveying system. According to one embodiment an air flow is achieved with at least one pump device, such as with a fan or with an extractor, which functions as a partial- vacuum generator 300A, 300B, 300C, 300D.

According to one embodiment the suction side of a partial-vacuum generator 300A, 300B, 300C, 300D, such as of a pump device, is connected to the top end 2 of the refuse chute 1.

According to one embodiment replacement air is brought into a refuse chute 1 from the bottom part 3 of the refuse chute or from the proximity of said bottom part.

According to one embodiment the properties of the air flow acting in the refuse chute 1 are regulated on the basis of at least one of the following parameters: the distance of the input point of the waste material 5 to the bottom part 3 of the refuse chute, the status of the shut-off valve V and/or of the input hatch 7 of the input aperture 4, the position of the input material in relation to the material space.

According to one embodiment the suction side of a partial-vacuum generator 300A, 300B, 300C, 300D, such as of a pump device, is connected to an intermediate tank 9 of the wastes, from which a connection 14 external to the refuse chute can be formed to the top end 2 of the refuse chute 1.

According to one embodiment in the method the suction of a partial-vacuum generator 300A, 300B, 300C, 300D acting in the top end 2 of the refuse chute 1 and/or in the intermediate tank 9 is restricted with at least one valve means 16, 9 and/or choke means 18. According to one embodiment the air flow is conducted from a refuse chute 1 into a separating device 200, 201 , 202, which is arranged in the path of flow of the medium between the top part 2 of the refuse chute and a partial-vacuum generator 300A, 300B, 300C, 300D.

According to one embodiment when emptying the bottom part of a refuse chute 1 the air flow in the refuse chute 1 is changed to travel in the direction of travel of the waste material 5. The invention also relates to an apparatus for achieving an air flow in a refuse chute 1 , which refuse chute comprises at least one input aperture 4 of waste material, from which input aperture 4 the waste material 5 fed into the refuse chute is fitted to move in the refuse chute under the effect of gravity to the bottom part of the refuse chute. The apparatus comprises means 14, 15, 16, 17, 18, 19, 20, 21 for achieving an opposing air flow with respect to the direction of travel of the waste material 5 in the refuse chute 1 with at least one partial-vacuum generator 300A, 300B, 300C, 300D to be used for the conveying of the wastes of a pneumatic waste conveying system. According to one preferred embodiment the means for achieving an opposing air flow with respect to the direction of travel of the waste material comprise at least one pump device 301 A...301 D, such as a fan or an extractor, which is used as a partial-vacuum generator 300A, 300B, 300C, 300D of the waste conveying system.

According to one embodiment for at least achieving an air flow opposite to the direction of travel of the waste material in the refuse chute, the suction side of a partial-vacuum generator 300A, 300B, 300C, 300D, such as of a pump device, is connected to the top end 2 of a refuse chute 1.

According to one embodiment the apparatus comprises means 15 for bringing replacement air into a refuse chute 1 from the bottom part 3 of it or from the proximity of it. According to one embodiment the apparatus comprises means for regulating the properties of the air flow acting in a refuse chute 1 on the basis of at least one of the following parameters: the distance of the input point of the waste material 5 to the bottom part 3 of the refuse chute, the status of the shut-off valve V and/or of the input hatch 7 of the input aperture 4, the position of the input material 5 in relation to the material space 6. ^' According to one embodiment the suction side of a partial-vacuum generator 300A, 300B, 300C, 300D, such as of a pump device, is connected to an intermediate tank 9 of the wastes, from which there is a connection 14 external to the refuse chute 1 onwards to the top end 2 of the refuse chute. According to one embodiment the apparatus comprises at least one valve means 16, 19 and/or choke means 18 to restrict the suction of a partial-vacuum generator acting in the top end 2 of the refuse chute and/or in the intermediate tank 9.

According to one embodiment the apparatus further comprises at least one intermediate tank 9 and/or separating device 200, 201 , 202, which is arranged in the path of flow of the medium between the top part 2 of a refuse chute 1 and a partial-vacuum generator 300A, 300B, 300C, 300D.

According to one embodiment, the apparatus is fitted to change the direction of travel of the air flow or to stop the air flow that is opposite with respect to the direction of travel of the material with a valve means 16 arranged in a connection line 14 that is external to the refuse chute 1 , at least when emptying the material space 6 of the bottom part of the refuse chute 1. It is obvious to the person skilled in the art that the invention is not limited to the embodiments presented above, but that it can be varied within the scope of the claims presented below. The characteristic features possibly presented in the description in conjunction with other characteristic features can, if necessary, also be used separately to each other.

Claims

1. Method for achieving an air flow in a refuse chute (1), which refuse chute comprises at least one input aperture (4) of waste material, in which method the waste material (5) fed into the refuse chute from an input aperture (4) is moved in the refuse chute under the effect of gravity to the bottom part of the refuse chute, cha racterized in that an opposing air flow with respect to the direction of travel of the waste material (5) is achieved in the refuse chute (1) with at least one partial-vacuum generator (300A, 300B, 300C, 300D) to be used for the conveying of the wastes of a pneumatic waste conveying system.

2. Method according to claim ^ c h a ra c t e r i z e d in that an air flow is achieved with at least one pump device, such as with a fan or with an extractor, which functions as a partial-vacuum generator (300A, 300B, 300C, 300D).

3. Method according to claim 1 or 2, characterized in that the suction side of a partial-vacuum generator (300A, 300B, 300C, 300D), such as of a pump device, is connected to the top end (2) of a refuse chute (1).

4. Method according to any of claims 1 - 3, c h a r a c t e r i z e d in that replacement air is brought into a refuse chute (1) from the bottom part (3) of the refuse chute or from the proximity of said bottom part.

5. Method according to any of claims 1 -4, c h a ra cte r i z e d in that the properties of the air flow acting in a refuse chute (1) are regulated on the basis of at least one of the following parameters: the distance of the input point of the waste material (5) to the bottom part (3) of the refuse chute, the status of the shut- off valve (V) and/or of the input hatch (7) of the input aperture (4), the position of the input material in relation to the material space.

6. Method according to any of claims 1 -6, c h a ra cte r i z e d in that the suction side of a partial-vacuum generator (300A, 300B, 300C, 300D), such as of a pump device, is connected to an intermediate tank (9) of the wastes, from which a connection (14) that is external to the refuse chute can be formed to the top end (2) of the refuse chute (1).

7. Method according to any of claims 1 -6, ch a racte ri zed in that in the method the suction of a partial-vacuum generator (300A, 300B, 300C, 300D) acting in the top end (2) of a refuse chute (1) and/or in an intermediate tank (9) is restricted with at least one valve means (16, 9) and/or choke means (18).

8. Method according to any of claims 1 -7, ch a racte rized in that the air flow is conducted from a refuse chute (1) into a separating device (200, 201, 202), which is arranged in the path of flow of the medium between the top part (2) of a refuse chute and a partial-vacuum generator (300A, 300B, 300C, 300D).

9. Method according to any of claims 1 -8, ch a ra cte ri zed in that when emptying the bottom part of a refuse chute (1) the airflow in the refuse chute (1) is changed to travel in the direction of travel of the waste material (5).

10. Apparatus for achieving an air flow in a refuse chute (1), which refuse chute comprises at least one input aperture (4) of waste material, from which input aperture (4) the waste material (5) fed into the refuse chute is fitted to move in the refuse chute under the effect of gravity to the bottom part of the refuse chute, characterized in that the apparatus comprises means (14, 15, 16, 17, 18, 9, 20, 21) for achieving an opposing air flow with respect to the direction of travel of the waste material (5) in the refuse chute (1) with at least one partial-vacuum generator (300A, 300B, 300C, 300D) to be used for the conveying of the wastes of a pneumatic waste conveying system.

11. Apparatus according to claim 10, characterized in that the means for achieving an opposing air flow with respect to the direction of travel of the waste material comprise at least one pump device (301 A...301 D), such as a fan or an extractor, which is used as a partial-vacuum generator (300A, 300B, 300C, 300D) of a waste conveying system.

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12. Apparatus according to claim 10 or 11, characterized in that for at least achieving an air flow opposite to the direction of travel of the waste material in the refuse chute the suction side of a partial-vacuum generator (300A, 300B, 300C, 300D), such as of a pump device, is connected to the top end (2) of a refuse chute (1).

13. Apparatus according to any of claims 10-12, characterized in that the apparatus comprises means (15) for bringing replacement air into the refuse chute (1) from the bottom part (3) of it or from the proximity of it.

14. Apparatus according to any of claims 10 - 13, characterized in that the apparatus comprises means for regulating the properties of the air flow acting in a refuse chute (1) on the basis of at least one of the following parameters: the distance of the input point of the waste material (5) to the bottom part (3) of the refuse chute, the status of the shut-off valve (V) and/or of the input hatch (7) of the input aperture (4), the position of the input material (5) in relation to the material space (6).

15. Apparatus according to any of claims 10-14, characterized in that the suction side of a partial-vacuum generator (300A, 300B, 300C, 300D), such as of a pump device, is connected to an intermediate tank (9) of the wastes, from which there is a connection (14) that is external to the refuse chute (1) onwards to the top end (2) of the refuse chute.

16. Apparatus according to any of claims 10-15, characterized in that the apparatus comprises at least one valve means (16, 19) and/or choke means (18) to restrict the suction of a partial-vacuum generator acting in the top end (2) of a refuse chute and/or in an intermediate tank (9).

17. Apparatus according to any of claims 10-16, characterized in that the apparatus further comprises at least one intermediate tank (9) and/or separating device (200, 201, 202), which is arranged in the path of flow of the medium between the top part (2) of a refuse chute (1) and a partial-vacuum generator (300A, 300B, 300C, 300D).

18. Apparatus according to any of claims 10- 7, characterized in that the apparatus is fitted to change the direction of travel of the air flow or to stop the air flow that is opposite with respect to the direction of travel of the material with a valve means (16) arranged in the connection line (14) that is external to the refuse chute (1), at least when emptying the material space (6) of the bottom part of the refuse chute (1).