EP0574850B1 - Removal of scrap material - Google Patents

Abstract

The invention relates to a method of removing scrap material, for example chips, from machining, in particular shaping workpieces by machining, by means of an air stream which is linked by means of flow paths (14, 16, 18) to at least one generating point (12), at which the scrap material produced there is taken up by the air stream and is entrained, if appropriate, with accompanying substances, such as lubricating, cutting or cooling fluid, and conveyed to a collecting point (20), at which the scrap material is separated from the accompanying substances and the conveying air and is stored until a predetermined storage volume has been reached, the conveying air initially being cleaned and subsequently discharged to the atmosphere. <IMAGE>

Description

The invention relates to a method for deriving machining residues, such as. B. chips, from mechanical processing, in particular machining shaping, of workpieces and a device for performing the method.

During the mechanical processing of workpieces, especially during machining, residues arise, e.g. B. in the form of chips that must be removed continuously to ensure the required processing quality. The residues generated on the cutting tool are removed from the workpiece by the lubricant, cutting agent or coolant, possibly by compressed air, and fed to a storage container placed next to the respective processing unit by means of a magnetic or chain conveyor. In this way, this storage container fills more or less quickly depending on the respective machining processes and must be emptied regularly or replaced by an empty container.

EP-0332093 A1 discloses a pollutant extraction device, in particular for wood processing, which is used to record pollutants at several extraction points and is assigned as a module to these extraction points so as to minimize the decentralized energy requirement.

The containers are usually emptied or replaced by personnel who are largely only involved in this activity and thus increase the production costs. Starting from this prior art, it is therefore an object of the invention to provide a method and an apparatus for Execution of the method to specify, with which the disposal of residues that occur at the respective processing stations takes place with at least partial preparation of the residues.

This object is achieved according to the invention by the features of claims 1 and 9. According to this, it is provided that the machining residues are discharged by means of an air stream which is connected via flow paths to at least one point of origin (= machining station) at which the residues accumulated there are captured by the air stream and, if necessary, entrained with their accompanying substances, such as lubricating or cutting fluid and are conveyed to a first collection point, at which the residues are stored until a predetermined storage volume is reached, the conveying air first being cleaned and then discharged to the environment. According to a preferred form of application of this method according to the invention, metal chips that occur during milling, turning, drilling or similar machining processes can be considered as machining residues.

After reaching the specified storage volume, the residues are separated from the accompanying substances and the conveying air. The air flow is advantageously generated by means of negative pressure by a device which is arranged at the predetermined collection point.

In a favorable development of the invention it is further provided that the delivery of the residues takes place periodically and that after each delivery period the respective flow path is flushed. This purging process is carried out individually for each point of origin, that is to say that the purging of the flow paths assigned to each point of origin takes place successively, whereby secondary air is sucked in at the respective point of origin, which left the relevant flow path of residues cleared, while the flow paths are blocked at the other origins.

A device according to the invention for carrying out the method described above is characterized in that a first collecting container is arranged at each point of origin, which serves to accommodate the locally accumulated residues, that this first collecting container is connected in terms of flow via a hollow line to a second collecting container . This second collecting container, which is provided for a certain number of first collecting containers, has a separating device for separating the delivered residues from possible accompanying substances, in particular lubricating and cutting fluid, and from the conveying air and is connected via a pipeline to a vacuum generator, e.g. B vacuum pump connected, which acts on the entire arrangement formed by the first collecting containers, hollow pipes and second collecting container with negative pressure. In an advantageous development of the invention, a vacuum generator is provided for every second collecting container.

According to a preferred embodiment of the invention, a control device is provided which carries out the automatic start-up of each vacuum generator.

In an expedient development of the invention, the hollow lines are designed as pipelines. Bends used each have a radius of curvature of at least two and a half times the tube diameter. Tube bends made of stainless steel, in particular austenitic steel, are preferably used for the bends, in particular for reasons of wear. Basically, according to the invention, the hollow lines can at least partially also be designed as a hose line, although this applies to areas with a low flow rate, e.g. B. immediately for the first collection containers.

To prevent wear-related damage, e.g. B. pipe breakage, and the associated danger from escaping flow material, the arch back can be reinforced.

According to one embodiment of the invention, the separating device arranged in the second collecting containers has a gravity or centrifugal force separator and a two-stage filter with a cloth filter as a prefilter and a cartridge filter as the main filter, the two-stage filter serving to clean the conveying air which flows through the cartridge filter the ambient air is removed.

Each first collecting container is designed as a suction funnel with a supply opening that is open at the top, with the separation of lubricating and / or cutting fluid optionally also being provided.

In addition, all the hollow lines adjoining a first collecting container are provided with shut-off elements, which are preferably designed as flat sealing slides, which can be actuated by means of actuators actuated by the control device, in particular pneumatically actuated piston-cylinder arrangements.

According to a special application variant of the invention, namely the disposal of long-chip residues, the z. B. incurred at turning and drilling stations, a shredding device is provided. Long-chip residues, e.g. B. in the form of spiral chips, often lead to disturbances due to their bulkiness with a small air attack surface by hooking them in the hollow pipes at any point and not from the flow air or difficult to let go. To avoid such malfunctions, each first collecting container, which is loaded with long chips from a turning or drilling station or a comparable manufacturing station, is connected to a shredding device, which first shreds the residues before they are discharged to the second collecting container via the connected hollow pipe .

A grinder or crusher with opposing cutting or crushing rollers is provided as the shredding device, in which the long-chip residues are shredded to a level that is specified by a perforated screen also arranged in the shredding device to maintain the specified residue size.

According to a preferred embodiment, in a disposal system according to the invention only such first collecting containers are connected via the hollow pipes to the second collecting container in which the same chip sizes occur, that is to say either only short comma-like chips or long-chip residues which first have to be comminuted.

In principle, however, a mixed arrangement is also possible, but the stations at which long-chip residues occur feed these residues to a comminution device, from which they are fed to the common collecting container in this case.

The number of first collecting containers connected to a second collecting container depends both on the respective local arrangement of the individual first collecting containers with respect to the second collecting container and on the available capacity of the vacuum generator.

These and other advantageous refinements and improvements of the invention are the subject of the dependent claims.

The invention, advantageous refinements and particular advantages of the invention are to be explained and described in more detail with reference to an exemplary embodiment of the invention shown schematically in the drawing.

Fig. 1:

eine erfindungsgemäße Vorrichtung zur Entsorgung von kurzspänigen Rückständen

Fig. 2:

eine Vorrichtung entsprechend Fig. 1 jedoch für langspänige Rückstände

In Figur 1 ist in schematischer Darstellung eine Vorrichtung 10 zur Entsorgung von kurzspänigen Rückständen wiedergegeben, welche aus verschiedenen Komponenten zusammengesetzt ist, nämlich ersten Sammelbehältern 12, die über Rohrleitungen 14, 16, 18 mit einem zweiten Sammelbehälter 20 verbunden sind, der seinerseits über eine Leitung 21 von einem Unterdruckerzeuger 22 beaufschlagt ist.Show it:

Fig. 1:

an inventive device for the disposal of short chips residues

Fig. 2:

a device according to FIG. 1, however, for long-chip residues

1 shows a schematic representation of a device 10 for the disposal of short chips, which is composed of various components, namely first collecting containers 12, which are connected via pipes 14, 16, 18 to a second collecting container 20, which in turn is connected via a line 21 is acted upon by a vacuum generator 22.

The lines 14 directly adjoining the first collecting containers 12 are each provided with shut-off elements 15, by means of which each collecting container 12 can be decoupled from the disposal line 16, 18. Furthermore, each line end of the lines 16 can also be closed with a shut-off device 17.

The second collecting container 20 is designed as a large collecting container and has a funnel-shaped outlet 24 with a slide 25, which is preferably pneumatically operated and is opened if necessary to empty the residues received in the second collecting container 20, for. B. in a lore 26th

The vacuum generator 22 ensures that a sufficiently high negative pressure is present at the respective first collecting containers 12 via the line paths 14, 16, 18 so that the waste material formed from short-chip residues and supplied to the first collecting containers 12 flows to the second collecting container 20. Depending on the size of the arrangement to be disposed of, a rotary piston blower or a vacuum pump of appropriate dimensions can be provided to generate the negative pressure. It should be taken into account that a larger vacuum is required for larger pipeline routes in order to achieve the required delivery rate. This in turn leads to a correspondingly larger vacuum generator.

In the second collecting container 20, which serves primarily as a receiving container for the short-chip waste material from the processing residues, a filter arrangement is also provided, which serves to clean the conveying air. Experience shows that the conveying air is interspersed with the residues of lubricants, cutting agents and coolants, e.g. B. cutting oil, which are usually used in the mechanical processing of workpieces to protect or cool the cutting tools. Although it is also provided on the first collecting containers that the oil that collects at the suction points is removed before suction, this is not completely successful, but some of these liquids adhere to the chip residues and are entrained with them by the conveying air.

The filter arranged in the second collecting container 20, which can be designed, for example, in two stages with a cloth filter as a prefilter and a safety particle filter cartridge as the main filter, is discharged to the surroundings via an air outlet 28 after the vacuum generator 22 located behind it has been flushed . Depending on the flow rate of the outflowing conveying air, the air outlet 28 can additionally be equipped with a silencer to reduce the noise level and thus reduce the environmental impact.

The pipe system formed from lines 14, 16, 18, 21 consists essentially of wear-resistant material, preferably austenitic stainless steel, the pipe bends, which have a minimum bending radius of 2.5 x pipe diameter, being reinforced on their back. The reinforcement can be done, for example, by welded-on U-profiles in the back area, which thereby prevent the residues flowing through the pipes at high speed from escaping in the particularly wear-stressed outside of the bend when the pipe breaks due to wear and can endanger the environment. If, despite the precautionary use of wear-resistant stainless steel, such pipe breakthroughs occur as a result of wear-related material removal on the inside of the pipe, the external reinforcement initially provides impact protection, whereby waste material escaping through the pipe wall collects in the space between the pipe outer wall and the reinforcement and thereby a buffer forms. The nominal size 80 with an inner diameter of 80 mm and a band thickness of 4 mm has proven to be the preferred dimension for the pipe dimensions.

The method of operation of the device 10 according to the invention is provided such that the suction of the individual processing stations, at which the first collecting containers 12 are arranged, takes place periodically after a predetermined time cycle. It is both provided that only one processing station, that is to say only one of the first collecting containers 12, is simultaneously subjected to negative pressure for a certain period of time via the lines 14, 16, 18. These requirements can optionally be set by a control system, not shown here, which controls both Vacuum generator as well as the individual shut-off devices 15, 17 are controlled and also implemented manually.

According to an advantageous procedure, the size of the first collecting container is determined in such a way that its volume is large enough to accommodate the amount of residue that arises in the interval between two working cycles of a first collecting container 12. The cross section of the suction lines 14, 16, 18 and 21 is also determined so that all waste material can be removed in the working period provided for each first collecting container 12.

When the entire disposal has been completed, that is to say when all the first collecting containers 12 have been emptied, the shut-off elements 17 arranged at the line ends of the lines 16 are opened, so that secondary air can enter and the line 16, 18 can be purged with air and cleared of residues. When these flushing processes have been completed, the control system ensures that the device 10 returns to its starting position and, if provided in accordance with the design, restarts.

FIG. 2 shows a device 11 which is very similar to the arrangement shown in FIG. In order to avoid repetitions, the same reference numbers are used for identical parts according to FIG. 1.

Also in the device 11 according to FIG. 2, a large number of first collecting containers 12 are each arranged at the sources of waste material, namely long-chip residues, which are usually mechanical machining centers, not shown, such as lathes, drilling machines and the like. Due to the long latency of the residues caused by this working method, in particular in the form of spiral chips, a trouble-free transport via the lines 14, 16, 18 is not safe. Often it happens that these spiral chips interlock on the inner wall of the pipeline and are no longer carried away by the conveying air flow. This can lead to considerable impairments of the disposal process, which means that the long-chip residues have to be reduced to a suitable size before being introduced into the air delivery system 14, 16, 18, 20. This comminution is provided in a striking or crushing unit 19, which is assigned to a plurality of processing stations, symbolized here by the first collecting containers 12.

This shredding device 19, which can have, for example, counter-rotating cutting rollers and a perforated plate with a hole size corresponding to the required chip size, is fed with long-chip residues via conveying paths 13 from the individual processing stations 12, which residues are shredded via the lines 14, 16, 18 in the second collecting container 20 arrive. Like the second collecting container 20 of the device 10 according to FIG. 1, the second collecting container 20 of the device 11 also has a gravity or centrifugal force separator, which separates the residues from the accompanying substances and from the conveying air. The chips that are sucked into the gravity or centrifugal force separator fall into a collecting container installed below the inlet opening, which is constructed as a discharge chute 24. This discharge chute 24, which is funnel-shaped, can be closed with a shut-off device 25. When the maximum fill level is reached, the shut-off device 25 is opened and the waste material received in the second collecting container 20 is either filled into a waiting transport cart 26 or - depending on the local facilities - into a waste recycling facility provided by the customer. Emptying is only possible when the vacuum generator 22 is at a standstill.

In principle, it is possible to combine a device 10 according to FIG. 1 with a device 11 according to FIG. 2. This depends on how many processing stations have to be disposed of. Since each first collecting container assigned to a processing station is emptied separately from the others and a certain time interval is required for each emptying process, there is a purely arithmetical calculation of a certain time grid, which leads to the disposal of a certain maximum per unit time with a device 10, 11 according to the invention Number of processing stations is only possible. If this maximum number is exceeded, it is more economical to provide a further device 10, 11 instead of enlarging the existing components, such as first collecting container 12 and second collecting container 20 and the vacuum generator 22.

Claims (23)

1. Method for removing machining residues such as, for example, chips from the mechanical machining, especially shaping involving the formation of chips, of workpieces by means of a stream of air which is connected via flow paths to at least one point of formation at which the residues which arise there are taken up by the air stream and entrained, where applicable with accompanying substances such as lubricants, cutting fluids or coolants, and conveyed to a collecting point at which the residues are stored until a predetermined storage volume has been reached, after which the residues stored at the first collecting point are fed via flow paths to a second collecting point, where they are separated from the accompanying substances and the conveying air and the conveying air is first of all cleaned and then discharged to the environment.
2. Method according to Claim 1, characterized in that the machining residues are chips which arise during milling, turning, drilling or similar machining processes employed on metals, ceramics and plastics.
3. Method according to Claim 1 or 2, characterized in that the air stream is produced by means of a vacuum, by a device which is arranged at the predetermined collecting point.
4. Method according to one of the preceding claims, characterized in that the conveyance of the residues takes place periodically and the [sic] each conveying period is followed by a process of flushing the flow path.
5. Method according to Claim 4, characterized in that the flushing operation is carried out separately for each point of formation.
6. Method according to Claim 5, characterized in that the flushing of the flow paths assigned to each point of formation takes place in succession by secondary air being drawn in as a result in each case of an inlet opening being opened, the secondary air freeing the flow path concerned from residues.
7. Method according to one of the preceding claims, characterized in that the residues are reduced in size before being acted upon by the air stream.
8. Method according to Claim 7, characterized in that the residues of great length, especially turning and drilling chips, are reduced in size.
9. Apparatus for carrying out the method according to one of Claims 1 to 6 with in each case a first collecting container (12), arranged at each point of formation, to receive the residues which arise there, which is connected in terms of flow, via a hollow conduit (14, 16, 18), to a second collecting container (20) which has a separating device for separating the residues conveyed to it from possible accompanying substances, in particular lubricants, cutting fluids and coolants, and from the conveying air and is connected by a pipe conduit (21) to a vacuum generator (22), e.g. a vacuum pump, which subjects the entire arrangement formed by the first collecting containers (12), the hollow conduits (14, 16, 18) and the second collecting container (20) to a vacuum.
10. Apparatus according to Claim 9, characterized in that a vacuum generator (22) is provided for each second collecting container (20).
11. Apparatus according to Claim 9 or 10, characterized in that a control device is provided which performs the automatic activation of each vacuum generator (22).
12. Apparatus according to one of Claims 9 to 11, characterized in that the hollow conduits (14, 16, 18) are designed as a pipe conduit.
13. Apparatus according to one of Claims 9 to 12, characterized in that bends each have a radius of curvature of at least 2.5 × the pipe diameter.
14. Apparatus according to one of Claims 9 to 13, [lacuna] in that austenitic steel is used as the material for the bends.
15. Apparatus according to one of Claims 9 to 12, characterized in that the hollow conduits (14, 16) are designed at least in part as a hose conduit.
16. Apparatus according to one of Claims 9 to 15, characterized in that each second collecting container (20) has as a separating device a gravitational or centrifugal separator and a two-stage filter with a cloth filter as a preliminary filter and a cartridge filter as a main filter.
17. Apparatus according to one of Claims 9 to 16, characterized in that each first collecting container (12) is designed as an extraction funnel with an upwardly open feed opening.
18. Apparatus according to Claim 17, characterized in that each first collecting container 12 has a device for separating out lubricating, cutting or cooling fluid.
19. Apparatus according to one of Claims 9 to 18, characterized in that each hollow conduit (14) adjoining a first collecting container (12) is provided with a shut-off element (15).
20. Apparatus for carrying out the method according to either of Claims 7 or 8 with the features according to one of Claims 9 to 19, characterized in that each first collecting container (12), which is supplied with long-chip residues, e.g. by a turning or drilling centre, interacts with a size reduction device (19) which is connected to the hollow conduit (14, 16, 18) [lacuna] to the second collecting container (20).
21. Apparatus according to Claim 20, characterized in that a tool with breaking or cutting rollers running in opposite directions is used as the size reduction device (19), the tool having a perforated screen to ensure compliance with the specified chip size.
22. Apparatus according to one of Claims 9 to 21, characterized in that the shut-off elements arranged in each hollow conduit (14, 16) are designed as flat sealing slide valves which can be actuated by means of actuators controlled by the control device.
23. Apparatus according to Claim 22, characterized in that pneumatically actuated piston-cylinder arrangements are provided as actuators.

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