WO2024012977A1

WO2024012977A1 - A loading unit for a conveying system for receiving waste objects through an inlet opening in the loading unit and use of said loading unit

Info

Publication number: WO2024012977A1
Application number: PCT/EP2023/068703
Authority: WO
Inventors: Harald Haug; Preben From Hansen
Original assignee: Nordic Recycling Systems Group A/S
Priority date: 2022-07-11
Filing date: 2023-07-06
Publication date: 2024-01-18
Also published as: DK181574B1; DK202200670A1

Abstract

A loading unit (4) for a conveying system (1) for receiving waste objects (2) through an inlet opening (24) in the loading unit (4). The loading unit (4) comprises an outlet port (6) through which the objects (2) leave the loading unit (4). The loading unit (4) is used in a pneumatic conveying system (1) that comprises pressure devices (8,9) for providing pressurized air/gas. The outlet port (6) of the loading unit (6) is a pneumatic outlet tube (POT) arranged for establishment of a suction in the POT (6); A pneumatic inlet tube (5) (PIT) of the loading unit is arranged for establishment of a positive pressure. By the suction and pressure, the waste objects (2) leave the loading unit (4) through the POT (6). A bottom part (33) is arranged between the PIT and the POT.

Description

A LOADING UNIT FOR A CONVEYING SYSTEM FOR RECEIVING

WASTE OBJECTS THROUGH AN INLET OPENING IN THE LOADING

UNIT AND USE OF SAID LOADING UNIT

The present invention relates to a loading unit for a conveying system for receiving waste objects through an inlet opening towards a bottom part of the loading unit, the loading unit comprises an outlet port being a pneumatic outlet tube (POT) through which the objects leave the loading unit, and that the loading unit is adapted to be used in a pneumatic conveying system that comprises pressure devices for providing pressurized air/gas; the loading unit further comprises a pneumatic inlet tube (PIT) arranged for establishment of a positive pressure,

Further the invention relates to use of use of the loading unit in a pneumatic conveying system comprising pressure devices for establishing the suction in the pneumatic outlet tube -POT- and the positive pressure in the pneumatic inlet tube - PIT.

Finally, the invention relates to use se of the loading unit for a container return system for waste material such as empty or partly empty beverage bottles and cans of any size.

This waste material may be items such as empty beverage bottles and cans of any size and material such as, plastic, steel, aluminum, glass, plastic said waste material is recycling waste material.

Pneumatic outlet tube is abbreviated to POT and pneumatic inlet tube is abbreviated to PIT.

Pneumatic conveying systems are used for transporting different kind of material such as food, com and granulates. Generally, air is blown through pipes via a pressure blower and similar in order to move the material through the pipe. In this way the material in question can be moved from one point to another point.

A container return system is generally arranged to collect waste containers for recycling. This may include used emptied beverage bottles and cans, or other waste material.

The container return system must collect large numbers of waste material for recycling in a short period of time. In many installations, the container return system delivers the received objects to a backroom receiving facility and the required space here can be considerable. Further it can also require means for sorting and storing the received objects. The space requirement and the complexity cause cost to the system.

In a typical installation, the crushed or compressed objects are transferred to a box and stored in plastic bags. The plastic bag is replaced when full. This also requires available space to store the full plastic bag and is time consuming. Further the container return system is often stopped when the box is full and an empty one is placed.

In order to handle recycling packages such as bottles and cans it is common to transport the objects on a transport band. This transport band runs from a delivery station, where the customer puts the bottle/can and to a box where the bottles/cans are collected.

Such system is known from WO 2022/013343 A. After the cans or bottles have been crushed, the crushed waste material is falling onto a buffer arrangement, and is further distributed and transported through the accompanying carrier assembly to be stored in a storage bin, which will contain the crushed material.

However, such a buffer arrangement/collecting unit for dropping down the items is not possible to use when the distribution and transport of the items is done by pneumatic lines. A pneumatic line for transporting the items has the advantage, that the waste material is transported away from the delivery station so fast, that the user just can empty large portions of the waste material into the delivery station without any risk for overloading the system. Further, instead for a small box or plastic bag to collect the transported items a large container can be placed outside the building where the system is working. The demand for staff to handle the reverse vending machine is thereby also reduced.

US4180354 A discloses a pneumatic tube transmission system for transmitting a carrier in which an object is placed from one terminal to a remote terminal to allow delivery of the carrier into an open remote terminal. When the carrier is transferred from the first terminal to the remote terminal, the carrier is positioned in the first terminal and the blower is activated to deliver positive pressure air through the first airline. A second airline draws a partial vacuum on the transmission line. This pressure/partial vacuum forces the carrier to move through the line to the remote terminal where the object is removed from the carrier. The system is not suitable for transporting objects continuously as the carrier is not able to be fed continuously and be emptied continuously. Every time an object is placed in the carrier the carrier is transported with the object to the remote terminal and then emptied. Then the carrier is transported back to its start position and fed again.

With other words it is desirable to be able develop an improved loading unit for a pneumatic working convey system for collecting and transporting waste material in such a way that the waste material can be handled without any delay and transported continuously away from the loading unit. The waste material is transported from the delivery station down to the loading unit and away from here so fast that the user just can empty large portions of the waste material into the delivery station from where it drops down into the loading unit without any risk for overloading the system.

The present invention seeks generally to improve loading units for handling waste objects such as bottles and cans such that the abovementioned insufficiencies and drawbacks of today’s loading units are overcome or at least it provides a useful alternative.

Up to this day, prior art has failed to teach a simple and yet reliable and inexpensive loading units which in a safe and reliable manner, without substantially increasing the cost of the system, is able to satisfy the abovementioned much desired characteristics of the mentioned loading units.

According to the invention, a pneumatic conveying system is provided, as per the introductory part of this specification, and wherein the pneumatic outlet tube (POT) is arranged for establishment of a suction in the POT, by said suction and positive pressure in the PIT the waste objects leave the loading unit through the POT, and the inlet opening of the loading unit points in the opposite direction of gravity, and the bottom part is arranged between the PIT and the POT and for receiving the waste objects.

The pressure devices may comprise any type of air-source such as a blower, air pump, fan, or other device capable of creating a pressure differential and for forcing air or other fluid, under pressure, through the loading unit. As such, the pressure devices are configured to generate a positive air-pressure in the PIT and a suction in the POT.

The waste material - such as empty plastic bottles or cans - drops down in the loading unit and reaches the bottom part. Laminar flow in the loading unit is caused by the pressure difference between the inlet convey line and the outlet convey line. The waste material is sucked into the POT and passes to a collecting unit which is typically a big container placed outside the building where the system is placed.

The loading unit receives the waste material without any delay. The waste material leaves the loading unit as soon it has reached near the bottom of the unit through the POT. The loading unit can operate nearly through the whole day without any interruptions.

The loading unit combines pneumatic vacuum transport and pneumatic overpressure transport and a control system controls the two pressures in such a way that we have nearly even pressure (0,9-1 bar) in the center of the loading unit, and a laminar flow of around 10-40 m/second. The waste material is in this way pushed into the POT of the loading unit, where the under-pressure sucks the material to a discharge convey line from where it is dropped down into the container. According to one embodiment the loading unit comprises guide plate(s), said guide plate(s) is/are adapted to regulate a flow of air/gas in the bottom part.

According to one embodiment the guide plate is a displaceable guide plate DGP adapted to be able to be moved in a vertical direction, whereby a part of the DGP is placed in the bottom part, and/or the guide plate is a guide plate adapted to be firmly anchored to the bottom part -a firmly guide plate FGP.

According to one embodiment the DGP comprises a plate which in an end pointing towards the bottom part is formed semicircular, i.e., essentially congruent with the bottom part, and the DGP by means is adapted to be slidable fastened to a wall of the loading unit and be fixed in a specific position.

According to one embodiment one or two different types of guide plates may be placed in the bottom part: a displaceable guide plate DGP and/or a firmly anchored guide plate FGP. They may both be placed in relation to the bottom part or only one is placed.

According to one embodiment the FGP comprises a plate with a surface parallel to a longitudinal direction of the bottom part and firmly fixed to the inside of the bottom part.

The DGP is placed close to the PIT. It comprises a flat and plane plate with one end congruent with the design of the bottom part that is semicircle shaped. The DGP is fastened slidable to a wall of the loading unit and with an attack surface substantially perpendicular or with a certain angle to the flow direction/horizontal direction. A longitudinal recess is placed in the DGP and a bolt is placed through the recess and fastened to the wall this making the DGP slidable. By the regulation of the DGP up and down to a specific position the air flow through the loading unit is regulated. Turbulence is then avoided and the DGP contributes to that the air flow is laminar and a flow of supplied objects flows continuously through the loading unit. The DGP may work alone or together with the other guide plate FGP.

The FGP may also work alone or together with the DGP. The FGP is fixed to the inside of the bottom part. It comprises a plate and a surface of the guide plate is arranged parallel to the longitudinal direction of the bottom part. It is placed close to the POT. It also contributes to the laminar flow of air in the bottom part in the same way as the DGP does and that turbulence is avoided in the loading unit.

According to one embodiment a tube with an opening pointing towards the inlet opening comprises the bottom part for receiving the objects, said tube is an extension of the PIT and the POT.

The bottom part is a horizontal half cylinder. The design is very suitable for receiving cans and bottles.

According to one embodiment the loading unit further comprises a hopper placed above the tube and connected to the tube with its walls and with an outlet opening in the bottom, allowing the objects to drop down into the tube through the opening in said tube.

The tube acts in this way as the bottom part of the loading unit. The upper part of the collecting unit for guiding the objects is formed as a hopper, and comprises an opening in the bottom matching an opening of the tube. The hopper is typically connected to the tube by welding the lower edge of the hopper to the outside wall of the tube. The tube thus forms the bottom part of the loading unit and is airtight connected to the hopper. The PIT and the POT are extended tubes from this tube/bottom part.

According to one embodiment the hopper comprises the inlet opening which is surrounded by the walls of the hopper, and opposite the inlet opening the walls surround the outlet opening. The outlet opening of the hopper has a size that allows the waste material to pass unhindered through but also sees to, that the waste material does not clump together and causes the loading unit to be overfilled and causes it to stall.

According to one embodiment that the walls of the hopper comprise four sidewalls a first side wall, a second side wall, a third sidewall, a fourth sidewall connected to each other forming a rectangular cross-section, and the shape of two opposite sidewalls having the largest length-extent and placed parallel with the longitudinal axes of the tube is trapezoidal shaped, whereby the two other opposite placed sidewalls placed above PIT and POT are slanted arranged relative to the vertical plane.

According to one embodiment the two opposite sidewalls having the largest length-extent are inclined relative to the vertical plane and converging towards the outlet opening.

By forming the hopper as described it is achieved that the waste material slide down to the bottom part as the sloping walls ensure optimal transport, and that the waste material lies with the longitudinal axis substantially parallel with the longitudinal axes of the loading unit.

According to one embodiment the rectangular cross-section area of the inlet opening is larger than the rectangular cross-section area of the outlet opening.

This helps to support the correct placement of the waste material in the loading unit

According to one embodiment the POT comprises openings placed at the lower part of the wall of the POT.

According to one embodiment the diameter of the openings placed in the lower part of the POT is 1 -5 mm. According to one embodiment the number of openings placed in the lower part of the POT is 5-30 preferably 10-20.

The conveying system may be contaminated by residues from the waste material dropped down in the loading unit. Waste containers returned for recycling, such as empty beverage bottles or cans, often contain residual liquids, which may come into contact with the system. In order to clean the system, the POT has openings with a diameter each of 1 -5 mm placed at the lower part of the wall of the POT. When water is dropped down in the loading unit it is sucked into the POT and due to the small openings, air from the outside is also sucked into the POT, working as an injector. This causes the water to atomize and is sucked further into the system cleaning it.

According to one embodiment the loading unit is placed in the pneumatic system and the pressure in the loading unit and in the PIT and the POT is controlled by a control-system configured to control the air/gas pressure from pressure devices, by said pressure the objects pass from the loading unit through the POT of the loading unit and through a discharge convey line to a collecting unit.

According to one embodiment the control system is adapted to control the pressure in such a way, that a laminar airflow is obtained in the region of the loading unit placed between PIT and POT.

Control of the pressure supports the achievement of a laminar air flow in the bottom part of the loading unit.

According to one embodiment the laminar airflow is around 10-40 m/s, and the pressure in the POT is below x bar of an ambient atmospheric pressure, and the pressure in the PIT is essentially x bar above an ambient atmospheric pressure.

The control system is adapted to control the pressure in the loading unit in such a way, that it contributes to a laminar airflow in center of the loading unit of around 10-40m/s, 15-35 m/s, preferably 25-30 m/s. This is done by regulating the pressure in PIT and the POT.

According to one embodiment a sensor is placed in relation to the loading unit said sensor is configured to register jamming of the loading unit.

The sensor is placed close to the loading unit in an opening in one of the walls of the hopper. The sensor registers if something goes wrong such as there is a risk of constipation of the loading unit.

By pneumatic transfer tubes is to understand, that the tubes are transporting under-pressure or over-pressure gas/air and are able to withstand the different pressures.

According to one embodiment the loading unit is placed on a frame arrangement.

The loading unit is placed on a frame arrangement is adapted to the conveying system also in the height.

According to one embodiment the objects are bottles and cans in can bottle and can deposit recycling systems.

Deposit recycling means recycling of materials where consumers pay a deposit.

Brief description of the drawings

FIG. 1A is a perspective view of a loading unit according to the invention seen from one end.

FIG. 1 B is a perspective view of the loading unit according to the invention seen from the opposite end shown in fig. 1A.

FIG. 2 is a sectional view through a loading unit shown in fig 1A, B. FIG. 3 is a perspective view of a pneumatic conveying system in which a loading unit as shown in fig 1A, B is arranged.

Fig 4 A,B shows a top view of the loading unit comprising two different types of guide plates fig 4C,D shows a perspective view of the loading unit comprising one guide plate a displaceable guide plate DGP. fig 4 E shows a top view of the loading unit comprising one guide plate a firmly placed guide plate FGP.

The invention will be explained with reference to fig. 1A, B and 2. This shows a loading unit 4 for receiving waste objects 2 - not shown - through an inlet opening 24 in the loading unit 4. The inlet opening 24 pointing opposite the direction of gravity. The loading unit 4 is adapted to be an integrated part of a pneumatic conveying system 1 as shown in fig. 3 that comprises pressure devices 8,9 for providing pressurized air/gas.

The loading unit 4 comprises a pneumatic outlet tube POT 6 through which the objects 2 leave the loading unit 4. A suction is established in POT 6. The objects are then transported through a discharge convey line 7 to a collecting unit 3 as shown in fig. 3.

The loading unit 4 further comprises a pneumatic inlet tube 5 (PIT) arranged for establishment of a positive pressure. By the suction and pressure the waste objects 2 leave the loading unit 4 through the POT 6.

The loading unit comprises a horizontal tube 19 an extension of/comprising the PIT 5 and POT 6. The loading unit 4 further comprises a hopper 20 placed above and on the tube 19 and connected to the tube 19 with its walls. It has an outlet opening 25 in the bottom, allowing the objects 2 to drop down into the tube 19 through an opening 32 in the tube 19 and towards a bottom part 33 of the tube 19. The outlet opening 25 has a size the allows the objects such as bottles and cans to pass unhindered through.

The walls of the hopper 20 comprises four sidewalls a first side wall 27, a second side wall 28, a third sidewall 29, a fourth sidewall 30. They are connected to each other forming a rectangular cross-section. The shape of the two opposite sidewalls 28,30 having the largest length-extent placed parallel with the longitudinal axes of the tube 19 is trapezoidal shaped. The two other opposite placed sidewalls 27,29 placed above PIT 5 and POT 6 - that is in the front and in the back - are slanted arranged. They are inclined relative to the vertical plane in the same direction. The two opposite sidewalls 28,30 having the largest length extent are also inclined relative to the vertical plane.

As a result, the waste objects 2 slide down to the bottom part 33 of the loading unit 4 as the slanted sidewalls direct the waste objects 2. The rectangular cross-section ensures that objects 2 are placed with their longitudinal axis parallel to the tube 19/the bottom part 33. As a result of the slanted arrangement and the diameter of the tube 19 is smaller than the width of the inlet opening 24, the rectangular cross-section area of the inlet opening 24 is larger than the rectangular cross-section area of the outlet opening 25.

The POT 6 comprises openings 17 placed at the lower part of the wall of the POT 6. The number of openings 17 is around 5-30, each with a diameter of 1-5 mm preferably 2-3 mm placed at the lower part of the wall of the POT 6. When water is dropped down in the loading unit 4 it is sucked into the POT 6 and due to the small openings 17, air from the outside is also sucked into the POT6, working as an injector. This causes the water to atomize and is sucked further into the system 1 the loading unit 4 is attached to and cleaning it.

A sensor in placed in relation to the loading unit 4. An opening 34 is made in one of the walls of the hopper 20 for placing and giving access to the sensor. The sensor will register jamming of the loading unit 4. The loading unit 4 is placed on a frame arrangement 21 in order to place it correct in relation to the pneumatic conveying system 1.

The loading unit 4 may also comprise one or two guide plates 35 placed in the bottom part 33. This is explained with reference to fig 4a-e.

Fig 4 a,b shows a top view of the loading unit 4 comprising two different types of guide plates 35: a displaceable guide plate DGP 36 and a firmly anchored guide plate FGP 37. They may both be placed in relation to the bottom part 33 or only one is placed.

The DGP 36 is placed close to the PIT 5. This is also shown in fig 4c, d showing a perspective view of the loading unit 4. The guide plate 35,36 comprises a flat and plane plate with one end congruent with the design of the bottom part 33 that is semicircle shaped. The plate 36 is fastened slidable to the first wall 27 of the hopper 20. A longitudinal recess 38 is placed in the DGP 36 and a bolt is placed through the recess 38 and fastened to the first wall 27 this making the DGP 36 slidable. It is placed close to the PIT 5. By the regulation of the DGP up and down to a specific position the air flow through the bottom part 33 is regulated. Turbulence is then avoided and contributing to that the air flow is laminar and the flow of supplied objects 2 continuous and without the risk of the system jamming. The DGP may work alone or together with the other guide plate FGP 37. The FGP 37 may also work alone. This guide plate 37 is shown in fig 4a, b Fig 4e shows a top view of the loading unit 4 with the guide plate FGP 37 placed in the bottom part 33. The FGP 37 works together with the DGP 36 or as shown in fig. 4 e it works alone. It comprises a plate fastened to the inside of the bottom part 33 and a surface of the guide plate 35,37 parallel to the longitudinal direction of the bottom part 33. It is placed close to the POT 6. It contributes to the laminar flow of air in the bottom part 33 in the same way as the DGP 36 does and that no turbulence takes place in the loading unit 4. A pneumatic conveying system is shown in fig 3 suitable for the loading unit 4 according to the invention.

An object 2 such as a plastic bottle is thrown down in the loading unit 4 for being transported through pneumatic conveying tubes. The object 2 is typically delivered from a deliver-station placed in a store, where the customer delivers his bottles/cans back to the store in order to have the waste objects 2 recycled. An object 2 is also seen in fig. 3 leaving the system through an outlet 14 of a pneumatic discharge convey tube 7. The objects 2 - delivered to the system 1- is delivered as a continuous flow. The customer may simply empty a whole sack of objects 2 into the deliverstation as the loading unit 4 is able to receive and handle the objects 2 without any delay.

Air/gas is flowing through the PIT 5, the central part of the loading unit 4 and POT 6. The POT 6 is flow connecting with an injector 11 through a second convey line 12, which is also air/gas flow connected to the discharge convey line 7. A pressure device such as a pressure blower 8 provides pressurized gas/air and is through a first convey line 18 air gas connected with the injector 11 and thereby the discharge tube 7.

The pressure blower 8 forms a negative air/gas pressure in the POT 6 due to the established gas/air flow lines through the injector 11 .

An air/gas pump 9 generates an air/gas flow through the PIT 5. A laminar airflow is then obtained in the central part of the loading unit 4 - around 15- 35 m/s - due to the pressure in the POT 6 is below a certain value x of an ambient atmospheric pressure (suction), and the pressure in the PIT 5 is above x bar of an ambient atmospheric pressure. Thereby the objects 2 pass from the loading unit 4 through the injector 11 and the discharge convey line 7, through the outlet 14 of the discharge convey line 7 into a collecting unit 3. The pressure is controlled by a control system 10.

The control system 10 controls the pressure in such a way, that the laminar airflow is obtained in the central region of the loading unit, and the pressure in the POT 6 and in the PIT 5 is as described above. The loading unit 4 according to the invention may off course be used in other pneumatic conveying systems than the one described.

Claims

1. A loading unit (4) for a conveying system (1 ) for receiving waste objects (2) through an inlet opening (24) towards a bottom part (33) of the loading unit (4)), the loading unit (4) comprises an outlet port (6) being a pneumatic outlet tube (POT) through which the objects (2) leave the loading unit (4) and that the loading unit (4) is adapted to be used in a pneumatic conveying system (1 ) that comprises pressure devices (8,9) for providing pressurized air/gas; the loading unit (4) further comprises a pneumatic inlet tube (5) (PIT) arranged for establishment of a positive pressure characterized in that the pneumatic outlet tube (POT) is arranged for establishment of a suction in the POT (6), by said suction and positive pressure in the PIT the waste objects (2) leave the loading unit (4) through the POT (6) and the inlet opening (24) of the loading unit (4) points in the opposite direction of gravity, and the bottom part (33) is arranged between the PIT and the POT for receiving the waste objects (2).

2. A loading unit (4) according to claim 1 characterized in that the loading unit (4) comprises guide plate(s) (35), said guide plate(s) (35) is/are adapted to regulate a flow of air/gas in the bottom part (33).

3. A loading unit (4) according to claim 2 characterized in that the guide plate(s) (35) is/are a displaceable guide plate DGP (36) adapted to be able to be moved in a vertical direction, whereby a part of the DGP (36) is placed in the bottom part (33), and/or the guide plate (35) is a guide plate (35) adapted to be firmly anchored to the bottom part (33) -a firmly guide plate FGP (37).

4. A loading unit (4) according to claim 3 characterized in that the DGP (36) comprises a plate which in an end pointing towards the bottom part (33) is formed semicircular, i.e. , essentially congruent with the bottom part (33), and the DGP (36) by means (38) is adapted to be slidable fastened to a wall of the loading unit (4) and be fixed in a specific position.

5. A loading unit (4) according to claim 2,3 or 4 characterized in that one or two different types of guide plates (35) may be placed in the bottom part: a displaceable guide plate DGP (36) and/or a firmly anchored guide plate FGP (37).

6. A loading unit (4) according to claim 3 or 5 characterized in that the FGP (37) comprises a plate with a surface parallel to a longitudinal direction of the bottom part (33) and firmly fixed to the inside of the bottom part (33).

7. A loading unit (4) according to any of the preceding claims characterized in that a tube (19) with an opening (32) pointing towards the inlet opening (24) comprises the bottom part (33) for receiving the objects (2) said tube is an extension of the PIT (5) and the POT (6).

8. A loading unit (4) according to claim 7 characterized in that the loading unit (4) further comprises a hopper (20) placed above the tube (19) and connected to the tube (19) with its walls and with an outlet opening (25) in the bottom, allowing the objects (2) to drop down into the tube (19) through the opening (32) in said tube (19).

9. A loading unit (4) according to claim 8 characterized in that that the hopper (20) comprises the inlet opening (24) which is surrounded by the walls of the hopper (20), and opposite the inlet opening (24) the walls surround the outlet opening (25).

10. A loading unit (4) according to claim 8 or 9 characterized in that the walls of the hopper (20) comprise four sidewalls a first side wall (27), a second side wall (28), a third sidewall (29), a fourth sidewall (30) connected to each other forming a rectangular cross-section, and the shape of the two opposite sidewalls (28,30) having the largest lengthextent and placed parallel with the longitudinal axes of the tube (19) is trapezoidal shaped, whereby the two other opposite placed sidewalls (27,29) placed above PIT (5) and POT (6) are slanted arranged relative to the vertical plane.

11 . A loading unit (4) according to claim 10 characterized in that the two opposite sidewalls (28,30) having the largest length-extent are inclined relative to the vertical plane and converging towards the outlet opening (25).

12. A loading unit (4) according to claim 8, 9,10 or 11 characterized in that the rectangular cross-section area of the inlet opening (24) is larger than the rectangular cross-section area of the outlet opening (25).

13. A loading unit (4) according to any of the preceding claims characterized in that the POT (6) comprises openings (17) placed at the lower part of the wall of the POT.

14. A loading unit (4) according to claim 13 characterized in that the diameter of the openings (17) placed in the lower part of the POT (6) is 1 -5 mm.

15. A loading unit (4) according to claim 13 or 14 characterized in that the number of openings placed in the lower part of the POT (6) is 5- 30 preferably 10-20.

16. A loading unit (4) according to any of the preceding claims characterized in that the loading unit is placed in the pneumatic system (1 ), and the pressure in the loading unit (4) and in the PIT (5) and the POT (6) is controlled by a control-system (10) configured to control the air/gas pressure from a pressure device (8,9), by said pressure the objects (2) pass from the loading unit through the POT (6) of the loading unit (4) and through a discharge convey line (7) to a collecting unit (3).

17. A loading unit (4) according to claim 16 characterized in that the control system (10) is adapted to control the pressure in such a way, that a laminar airflow is obtained in the region of the loading unit (4) placed between PIT (5) and POT (6),

18. A loading unit (4) according to claim 17 characterized in that the laminar airflow is around 10-40 m/s, and the pressure in the POT (6) is below x bar of an ambient atmospheric pressure, and the pressure in the PIT (5) is essentially x bar above of an ambient atmospheric pressure.

19. A loading unit according to any of the preceding claims characterized in that a sensor is placed in relation to the loading unit (4) said sensor is configured to register jamming of the loading unit (4).

20. A loading unit according to any of the preceding claims characterized in that the loading unit (4) is placed on a frame arrangement (21 ).

21. A loading unit (4) according to any of the preceding claims characterized in that the objects (2) are bottles and cans in can bottle and can deposit recycling systems. Use of a loading unit (4) according to claim 1-21 in a pneumatic conveying system (1 ) comprising pressure devices (8,9) for establishing the suction in POT (6) and the positive pressure in the PIT (5). Use of a loading unit (4) according to claim 1-22 for a container return system for waste material such as empty or partly empty beverage bottles and cans of any size.