Pressing device

Abstract

Pressing device (1), in particular a channel baler, with a pressing channel (2) in which a press ram (5) is movable, which is driven by a hydraulic device (7) comprising a piston-cylinder unit (8, 9) supplied by a hydraulic fluid (15) from a tank (14), characterized in that at least one connection for air supply is provided on the tank (14) above the fluid level (16) of the hydraulic fluid, which is connected to a closed inflatable container (35), wherein a vacuum relief valve (33) and / or a pressure relief valve (32) is provided in a line between the tank (14) and the container (35).

Description

[0001] The present invention relates to a pressing device, in particular a channel baler, having a pressing channel in which a pressing ram is movable, which is driven by a hydraulic device comprising a piston-cylinder unit supplied by a hydraulic fluid from a tank.

[0002] DE 10 2005 003 397 A1 discloses a channel baler in which a baling channel is provided for compressing waste or other loose materials into bales. This baling channel can be filled through a top-opening filling chute. A movable press ram is provided in the press ram to compress and tie the filled material into bales. A hydraulic pressure medium drive is provided to drive the press ram, which can be moved over long distances, so that the tank containing the hydraulic fluid draws in a large amount of ambient air when it is emptied. The ambient air is filtered in the process, whereby the filters can become clogged, especially in dusty air.

[0003] DE 2 208 575 A discloses a device for generating atmospheric pressure in a container filled with a liquid and a gaseous medium. A flexible diaphragm is arranged in the container to form a chamber.

[0004] DE 100 38 982 A1 discloses a fluid reservoir as an expansion tank in a hydraulic system of motor vehicles. To prevent pressure fluctuations in a fluid reservoir during gas or air exchange, a bellows is provided, which is mounted in the hydraulic reservoir.

[0005] US 3,359,730 A discloses a reservoir for brake fluid in hydraulic brakes. A bellows is provided to prevent pressure fluctuations.

[0006] EP 0 616 969 A1 discloses a hydraulically driven elevator in which a hydraulic fluid is arranged in a reservoir and can be pumped. To prevent a natural degradation process, nitrogen is used in the reservoir instead of air.

[0007] It is therefore an object of the present invention to provide a pressing device which can be used particularly well in a dusty environment.

[0008] This object is achieved with a pressing device having the features of claim 1.

[0009] In the pressing device according to the invention, the hydraulic device for driving the pressing ram is supplied with hydraulic fluid via a tank provided with an air supply connection above the hydraulic fluid level, which is connected to a closed, inflatable container. This allows the air sucked into the tank and then expelled again to be collected and released from the container, which is sealed from the environment. This ensures that even with a high dust concentration at the pressing device, for example, when waste materials such as waste paper are compressed into bales using the pressing device, the hydraulic device is not affected by the dust. This avoids the need to change any filters on the supply to the tank too frequently.

[0010] According to a first embodiment of the invention, a vacuum valve is provided in a line between the tank and the container. The vacuum valve prevents damage to the hydraulic device, for example, because no more air can be drawn from the empty container and damage could occur due to a vacuum caused by the movement of the press ram. This is prevented by the vacuum valve because when the pressure falls below a certain negative pressure, for example, 0.2 bar or 0.4 bar, the vacuum valve opens, allowing ambient air to be drawn in. To prevent contamination, a filter can be provided upstream of the vacuum valve.

[0011] Furthermore, in a second embodiment of the invention, a pressure relief valve is provided in the line between the tank and the container. An increase in pressure in the tank, for example because the container is already completely filled with air, can also cause damage. To prevent the container from bursting, the pressure relief valve can release air into the environment in such a case, for example at an overpressure of 0.2 bar or at least 0.4 bar. For this purpose, a valve body preloaded by a spring can be provided on the vacuum valve and / or the pressure relief valve. For a compact design, the pressure relief valve and vacuum valve can also be provided on a common fitting, which is, for example, firmly attached to a connection on the tank.

[0012] The container is preferably designed as a bag. The container can be easily suspended from the pressing device and can expand or contract depending on the fill level. To simplify production of the container, two layers welded together can be provided, to which one or more nozzles are provided for connecting a connecting line. Preferably, the container is connected to one or more fittings or the tank via several lines so that a large volume exchange can take place between the tank and container without high pressure losses. A flexible material can be used as the material for the container, but preferably one that has a low extensibility of less than 10%. For example, plastic films can be used to manufacture the container, which can be easily produced and sealed by welding two layers.It is not necessary to place the container in another closed housing.

[0013] The invention is explained in more detail below using an exemplary embodiment with reference to the accompanying drawing. It shows: Fig. 1 a schematic view of a pressing device according to the invention.

[0014] A pressing device 1 is designed as a channel baling press and comprises a pressing channel 2, which may be cylindrical, rectangular, or of a different geometry in cross-section. The pressing channel 2 is surrounded by a housing 3 in which a pressing ram 5 is movably arranged. The pressing ram 5 is used to compress material that is introduced into the pressing channel 2 via a filling hopper 22, for example loose materials such as waste paper, waste, or other materials. The loose material can be formed into bales 4 via the pressing ram 5, with a closure element 17 arranged in the pressing channel 2 for this purpose, which serves as a stop. By moving the pressing ram 5, the formed bale 4 can be discharged via an outlet 18 after the closure element 17 has been removed. The closure element 17 is movable via a hydraulic device with a piston 19 and a housing 20, which are provided on a holder 21.Other drives for moving the closure element 17 can also be used.

[0015] The press ram 5 is driven by a hydraulic device 7, which has a cylinder 8 connected to the press ram 5 and a piston 9, which are movable relative to one another. The piston-cylinder unit of the hydraulic device 7 is supported by schematically illustrated fastening means 11 on a holder 10 arranged in the press channel 2. Furthermore, the hydraulic device 7 is connected to a schematically illustrated pump 12, which can also be arranged directly on the piston 9. The pump 12 for pumping the hydraulic fluid is connected via a line 13 to a tank 14 for hydraulic fluid 15. Due to the movement of the piston-cylinder unit with the press ram 5 within the press channel 2, a fluid level 16 of the hydraulic fluid 15 in the tank 14 will fall or rise.In order to compensate for the volume equalization, a connection 30 is provided above the liquid level 16, which serves to introduce or discharge air from the tank 14.

[0016] A fitting 31 is provided at the connection 30, which has a pressure relief valve 32 and a vacuum valve 33. Furthermore, the fitting 31 is connected by a line 34 to an inflatable container 35, which can absorb or release the air extracted from the tank 14. The container 35 is designed to be closed, so that dust from the environment cannot enter the hydraulic device 7.

[0017] The container 35 preferably consists of two layers of a single- or multi-layer plastic film, which are welded together at the edges and can thus expand and contract. The bag-shaped container 35 can be suspended from a holding means 36 by an edge seam or a projection of the film, which is provided, for example, on the tank 14 or another part of the pressing device 1. Due to the low weight of the container 35, the mechanical load on the holding means 36 is low.

[0018] To initially fill the container 35 with air, a vacuum valve 33 is provided. This opens when the pressure falls below a predetermined level, for example, at a vacuum of 0.2 bar or 0.4 bar, and thus draws in air from the environment. A filter can be provided upstream of the vacuum valve 33 so that only filtered air enters the container 35 and the tank 14. The vacuum valve 33 also prevents excessive vacuum from being generated during operation of the press ram 5, which could cause damage.

[0019] Furthermore, a pressure relief valve 32 is provided, which prevents the container 35 from bursting if the volume within the system becomes too large, allowing excess air to be released when a certain overpressure is exceeded, for example, at 0.2 bar or 0.4 bar. The pressure relief valve 32 and the vacuum valve 33 can each have a spring-loaded valve body and can be easily mounted on the fitting 31.

[0020] In the illustrated embodiment, only a single fitting 31 is shown, which is connected to the tank 14 and supplies the container 35 via the line 34. In order to be able to conduct larger volume flows without significant pressure loss between the container 35 and the tank 14, several lines 34 can also be provided in parallel between the container 35 and the tank 14, with a fitting 31 preferably being provided on each line 34 in order to be able to fulfill the corresponding functions under overpressure and underpressure. Optionally, at least some of the lines 34 can of course also be connected directly to the tank 14.

[0021] To prevent the line 34 from contracting in the event of a negative pressure, a hose is preferably used which is reinforced with a reinforcing core to prevent contraction, for example with a steel core. List of reference symbols 1 pressing device 2 press channels 3 housings 4 bales 5 press stamps 7 Hydraulic device 8 cylinders 9 pistons 11 Fasteners 10 holders 12 Pump 13 Management 14 tanks 15 Hydraulic fluid 16 liquid levels 17 Closure element 18 Outlet 19 pistons 20 housings 21 holders 22 filling funnels 30 connection 31 fitting 32 pressure relief valve 33 Vacuum valve 34 Line 35 containers 36 holding devices

Claims

[1] Pressing device (1), in particular a channel baling press, with a pressing channel (2) in which a pressing ram (5) is movable, which is driven by a hydraulic device (7) comprising a piston-cylinder unit (8, 9) supplied by a hydraulic fluid (15) from a tank (14), characterized by that at least one connection for air supply is provided on the tank (14) above the liquid level (16) of the hydraulic fluid, which connection is connected to a closed inflatable container (35), wherein a vacuum valve (33) and / or a pressure relief valve (32) is provided in a line between the tank (14) and the container (35). [2] Pressing device according to claim 1, characterized by that the pressure relief valve (32) and the vacuum valve (33) are provided on a common fitting (31) through which a flow path of the air is passed between the tank (14) and the container (35). [3] Pressing device according to claim 1 or 2, characterized by that the container (35) is designed as a bag. [4] Pressing device according to one of the preceding claims, characterized by that the container (35) is fixed in a hanging manner on the pressing device (1). [5] Pressing device according to one of claims 1 to 4, characterized by that the pressure relief valve (32) and / or the vacuum valve (33) open at a pressure difference of at least 0.2 bar, in particular at least 0.4 bar. [6] Pressing device according to one of claims 1 to 4, characterized by that the pressure relief valve (32) and / or the vacuum valve (33) have a valve body pre-tensioned by a spring. [7] Pressing device according to one of the preceding claims, characterized by that several connections are provided on the tank (14) which are connected to the container (35). [8] Pressing device according to one of the preceding claims, characterized bythat a hose with a reinforcing core is provided at least partially to connect the tank (14) to the container (35) to prevent contraction under negative pressure. [9] Pressing device according to one of the preceding claims, characterized by that the container (35) has two layers welded together. [10] Pressing device according to one of the preceding claims, characterized by that the container (35) consists of a flexible but less than 10% stretchable material.

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