DE10321438A1 - Combustible swarf extraction unit has detectors in cyclone controlling delivery unit to prevent ignition of collected material - Google Patents

Abstract

A combustible swarf extraction unit has a delivery unit (14) between cyclone (10) and sand (91) filled collection container (90) with ignited substance particle infrared detectors in the extraction unit inlet (11) and below the cyclone (12) operating an optical or acoustic warning (20) and stopping the delivery unit until the particle extinguishes.

Description

The Invention relates to an extraction system for the extraction of flammable, machined materials according to the generic term of claim 1.

Extraction systems are essential when machining materials. Problems arise, however, when materials are processed whose chips and dusts are comparatively easily flammable. Examples of such materials are titanium, aluminum, aluminum-lithium alloys and fiber composites. Glare ^{® should also be} mentioned, which is a glass fiber reinforced metal laminate. This material consists of thinly rolled aluminum layers that are alternately bonded with plastic layers that are reinforced by high-strength glass fibers. It is particularly well suited as a material in aircraft construction. With these and other materials, chips or dust can ignite during machining. Since this ignition cannot be completely eliminated in terms of process technology, it is necessary to design plants and machines in such a way that larger fires are prevented.

From the German patent specification DE 39 04 312 is a suction device for industrial purposes for the disposal of dusty or fine-particle, flammable groupage, such as metal chips made of magnesium. It has a collecting container which receives the collecting material sucked in via an intake line. A suction unit is generated by means of a downstream suction unit, a separating device arranged between the collecting container and the suction unit separating the groupage and suction air from one another. To prevent fire, it is provided that a protective device is provided which can be triggered by the development of heat inside the collecting container and which interrupts the suction draft. The suction train is interrupted by switching off the suction unit and closing the suction line. As a result, the fire suffocates inside the suction device, since fresh air is not supplied. Furthermore, the opening between the collecting container and the separating device can be closed by a closure member. This helps to extinguish the fire more quickly. An extinguishing agent can also be sprayed into the collecting container. The fire is detected thermally, for example with the help of an electronic heat sensor. The disadvantage of this suction device is that the suction is interrupted for fire fighting. Machining must be interrupted as a result, so that with automatic or semi-automatic machining not only the suction unit must always be switched off, but also the machining and other devices connected to it. As a result, there are major interruptions in the production process.

task According to the present invention, a suction device is available ask which reliable a fire when extracting flammable, machined materials prevented, the suction unit, however, are operated continuously can.

This Task is solved by an extraction system according to claim 1. Advantageous refinements are the subject of the subclaims.

The suction system according to the invention has the corresponding from DE 39 04 312 known suction device on a collecting container and a cyclone, in the upper area of which an intake line is arranged, with which the machined materials are fed to the cyclone. Furthermore, the suction system also has a flow generator which is connected downstream and which generates a suction flow. According to the invention, a discharge device is now provided between the cyclone and the collecting container, which discharges the machined materials from the cyclone and feeds them to the collecting container. Furthermore, at least one spark detection device is provided according to the invention, which detects an ignited, machined material particle. A control is also provided which switches off the discharge device when the spark detection device detects an ignited material particle. The discharge device can preferably only be switched on again when no more ignited material particles can be detected. The measures according to the invention separate the ignited chip from the chips deposited in the collecting container. If an ignited material particle is present in the cyclone, the discharge of material particles into the collection container is interrupted. As a result, the ignited material particle remains in the cyclone, where it burns up. A controlled combustion of this ignited material particle is consequently carried out. Since, in contrast to the device known from the prior art, only comparatively few material particles and chips are present in the cyclone at the same time as the burning material particle, larger fires are prevented. The fire cannot be transferred to the particles and chips deposited in the collection container. As a result, a burning chip has no major impact. The flow generator remains in operation and continues to suction. As a result, machining and all subsequent processes can continue. This brings significant production and process advantages. The continuous operation of the flow generator also has the advantage that the control The burnt-up of the ignited material particle takes place quickly because fresh air is continuously supplied.

As Spark detection device is preferably an infrared sensor provided, which is preferably arranged in the entrance area of the suction system is. Consequently, one becomes inflamed Material particles detected when entering the extraction system whereby the discharge device is switched off. Preferably there is a second spark detection device in the exit area of the cyclone, in particular, another infrared transmitter is also provided inflamed Material particles detected. Consequently, the preferred process looks before that once an inflamed Material particles have been detected by the first spark detection device is, a control switches off the discharge device. The discharge device can only be switched on again or is activated by the control switched on when no ignited Material particles are more in the cyclone. This can be determined by using the second spark detection device, for example after a certain period of time proves that no ignited material particles is detectable. Furthermore, it can also be provided that the discharge device is switched off or remains, even if the second spark detection device an ignited material particle is detected in the exit area of the cyclone. An alternative embodiment, in which a second spark detection device in the exit area of the cyclone unnecessary is can provide that the discharge device after a can be switched on again after a certain period of time. This period corresponds the time that passes until a burning material particle has burned up. It can be determined experimentally, preferably a certain security surcharge is added.

As preferred embodiments a discharge device are a cellular wheel sluice, a flap sluice or a slide is provided. The collection container can also be sand or heavy flammable liquid partially filled, whereby a further increase in security can be achieved that even in the case where a not yet completely burned up but not detected inflamed Material particles are discharged into the collection container Fire is suppressed.

On another preferred embodiment stipulates that the extraction system is not only the one described above Cyclone, but additionally has a filter cyclone, which via a suction line with the Cyclone is connected. A post-cleaning is thereby achieved, whereby in particular it is provided that the first cyclone of the separation the coarser Material, especially chips, and the filter cyclone, serves to separate fine particles, especially fine dust. This filter cyclone has one according to the invention Pressure sensor, which detects a pressure increase in the filter cyclone, such as that caused by an explosion. Thereby an extinguishing agent container is activated, so extinguishing agent is introduced into the filter cyclone. This will extinguish the fire. Basically, too two cyclones described above can be arranged in order to achieve a two-stage purification because of the fire risks from coarser Particles and finer particles are different is preferred a filter cyclone downstream. While coarser chips tend to cause fires by they ignite other particles, to lead inflamed dusts more like explosions. As a result, is in the downstream filter cyclone explosion suppression protection intended. It is also preferably provided that the detected pressure increase in the filter cyclone, a quick-closing slide between the filter cyclone and cyclone and can be closed between filter cyclone and flow generator. As a result, the filter cyclone is decoupled in terms of explosion technology prevents the explosion from spreading upstream and downstream becomes. The filter cyclone can also have a discharge device, in particular have a rotary valve, whereby the collecting container of the filter cyclone is isolated and separated. This also helps to increase the Fire safety at.

following the invention is explained and described in more detail with reference to the drawings. Show it:

1 A schematic representation of an extraction system according to the invention;

2 a schematic representation of a cyclone of an extraction system according to the invention;

3 a side view of a filter cyclone of an extraction system according to the invention; and

4 a section through the filter cyclone 3 ,

1 shows a schematic representation of an extraction system according to the invention 1 , This has a cyclone 10 on and a filter cyclone 50 , It is also at the top of the cyclone 10 an intake pipe 2 is arranged, via which machined materials the cyclone 10 are fed. cyclone 10 and filter cyclone 50 are via a suction line 3 connected with each other. A flow generator 5 generates a suction flow. He is the cyclone 10 and the filter cyclone 50 downstream. In the 1 Arrows indicate the course of the flow generator 5 generated suction flow. The air and thus the machined material particles are removed via the intake pipe 2 sucked in and the cyclone 10 fed. In the cyclone 10 the coarser material particles are separated. The suction flow is then via the suction line 3 the filter cyclone 50 fed. Fine dust is contained in the suction air and consequently also in the filter cyclone 50 reach. The suction air is there through the filter 51 passed and leaves via another suction line 4 the filter cyclone 50 , The groupage, i.e. the machined coarser and finer material particles, are collected in at least one collection container. The suction system 1 the 1 points for the cyclone 10 and for the filter cyclone 50 each a separate collection container 90 and 95 on.

Based on 1 and 2 becomes the cyclone 10 explained in more detail. The cyclone 10 has an elongated container 17 on. In the upper area 16 is the suction pipe 2 arranged over which the material particles the container 17 are fed. In the area below 15 of the container 17 is a discharge device, more precisely a rotary valve 14 intended. The rotary valve can, as in 2 shown, for example, have 6 chambers. It is particularly pressure shock-proof, flame-proof and flame-proof. How to use the exemplary path (dashed line) of a material particle 30 results in the container 17 of the cyclone 10 centrifugal separation. By arranging the intake line 2 in the upper area 16 of the cyclone becomes the entire height of the cyclone 10 used for this. This results in the separation of material articles 30 which are in particular larger than approximately 10 μm. If the material particle 30 in the lower area 15 has reached, it is with the help of the rotary valve 14 discharged from the container 17 and the collection container 90 fed. This is with sand 91 filled. The cyclone 10 is with two spark detection devices 11 and 12 fitted. The first spark detection device 11 is on the suction pipe 2 arranged. Alternatively, it can also be in the upper area 16 of the container 17 be arranged. It is only important that the first spark detection device 11 in the entrance area of the extraction system 1 and / or the cyclone 10 located. The spark detection device 12 is in the lower range 15 of the container 17 intended. With the spark detection devices 11 and 12 it is preferably infrared sensors that detect inflamed material particles. With the help of a controller 13 becomes the rotary valve 14 controlled. As soon as a spark is detected, the cellular wheel sluice 14 stopped. It is only put back into operation when the chip has burned off. Consequently, a burning material particle happens 30 the spark detection device 11 , the control stops 13 the cellular wheel sluice 14 on; the discharge of material particles is interrupted. Detects the spark detection device 12 after a certain time no more burning material particles, the control system continues 13 the cellular wheel sluice 14 going again; the discharge is resumed. An optical or acoustic warning device is also preferred 20 provided that reports when a burning material particle 30 is through the spark detection device 11 has been detected and the rotary valve 14 has been stopped. At the warning device 20 it can be, for example, a lamp, in particular an all-round lamp. Various warning signals can also be provided. A first warning signal can thus be provided, which indicates that a burning spark has been detected and the discharge device 14 has been stopped. A second signal can also be provided if the thermal combustion process of the ignited material particle 30 takes longer than usual. In other words, this second warning signal can be emitted when the rotary valve 14 has not been put into operation again for longer than a predetermined time. Such a time period can be, for example, half a minute to one minute. This means that there is a malfunction that can be investigated in more detail.

Based on a summary of the 1 . 3 and 4 becomes the filter cyclone 50 explained in more detail. The filter cyclone 50 assigns a container 57 on, in the upper area 55 the suction line 3 empties. The raw gas entry is in the 3 and 4 with the reference symbol 63 Mistake. It is also located in the upper area 55 the clean gas outlet, in 3 with the reference symbol 62 designated. The suction air therefore comes from the suction line 3 about the raw gas entry 63 inside the container 57 is through the filter cartridge 51 passed through and leaves the container 57 through the clean gas outlet 62 into the suction ladder 4 , Between clean gas outlet 62 and filter cartridge 51 there is a clean gas room 61 in which also a compressed air tank 60 is arranged. It can be a filter cartridge 51 be arranged as in the embodiment of 1 , however, several filter cartridges can also be arranged, for example three filter cartridges 51a . 51b and 51c , as in 4 shown. Near the filter cartridge 51 is a pressure sensor 52 arranged. This detects an increase in pressure in the container 57 due to an explosion. There is an extinguishing agent container to suppress the explosion 53 provided which extinguishing agent in the container 57 einsprüht. This is activated as soon as the pressure sensor 52 an increase in pressure in the container 57 detected. There are also two quick-closing slides 70 and 71 in the suction line 3 respectively. 4 intended. They are also activated as soon as the pressure sensor 52 a print rose detected. If the pressure increases, the quick-closing slides become 70 and 71 closed, causing the filter cyclone 50 from the rest of the extraction system 1 is decoupled. In the area below 56 of the container 57 is a rotary valve 54 provided, which carries out the introduced and cleaned particles and dusts and the collection container 95 feeds, which also with sand 91 or an extinguishing agent can be filled. By detecting a pressure increase in the filter cyclone 50 can the rotary valve 54 also be stopped to spread the explosion to the collection container 95 to prevent.

In order to facilitate maintenance work and the replacement of filter cartridges, there is also an inspection door 65 provided through the inside of the container 57 is accessible.

Claims (11)

Extraction system for the extraction of flammable, machined materials with at least one collecting container, a cyclone, in the upper area of which a suction line is arranged, via which the machined materials are fed to the cyclone, and a downstream flow generator, which generates a suction flow, characterized in that a Discharge device ( 14 ) between cyclone ( 10 ) and collection container ( 90 ) is provided, which discharges the machined materials from the cyclone and feeds them to the collection container, further characterized in that at least one spark detection device ( 11 . 12 ) is provided, which contains an ignited, machined material particle ( 30 ) detected and that a controller ( 13 ) is provided, which switches off the discharge device when the spark detection device detects an ignited material particle. Extraction system according to claim 1, characterized in that the spark detection device ( 11 ) in the entrance area of the extraction system ( 1 ) is arranged. Extraction system according to claim 2, characterized in that a second spark detection device ( 12 ) in the area below ( 15 ) of the cyclone ( 10 ) is arranged. Extraction system according to one of the preceding claims, characterized in that the spark detection device ( 11 . 12 ) is an infrared sensor. Extraction system according to one of the preceding claims, characterized in that the discharge device ( 14 ) is a cellular wheel sluice, flap sluice or a slider. Extraction system according to one of the preceding claims, characterized in that a warning device ( 20 ), in particular an optical or acoustic, a light or rotating light, is provided which can be activated when the spark detection device ( 11 . 12 ) detects an ignited material particle. Extraction system according to one of the preceding claims, characterized in that in addition a filter cyclone ( 50 ) is provided, which is connected via a suction line ( 3 ) with the cyclone ( 10 ) is connected so that material particles, especially fine dust, are transferred to the filter cyclone, the filter cyclone being a pressure sensor ( 52 ), which detects an increase in pressure in the filter cyclone, and wherein an extinguishing agent container ( 53 ) is provided, which can be activated when the pressure sensor detects an increase in pressure in the filter cyclone. Extraction system according to claim 7, characterized in that at least two quick-closing slides ( 70 . 71 ) in the suction line ( 3 . 4 ) are arranged that can be activated when the pressure sensor ( 52 ) an increase in pressure in the filter cyclone ( 50 ) detected. Extraction system according to claim 7 or 8, characterized in that a discharge device ( 54 ), especially a rotary valve, on the filter cyclone ( 50 ) is arranged, the separated material particles a collecting container ( 95 ) feeds. Extraction system according to claim 9, characterized in that the discharge device ( 54 ) can be switched off if the pressure sensor ( 52 ) an increase in pressure in the filter cyclone ( 50 ) detected. Extraction system according to one of the preceding claims, characterized in that in the collecting container ( 90 . 95 ) Sand ( 91 ) or a flame-retardant liquid is provided.