CN221713816U

CN221713816U - Filter device for cleaning a raw gas carrying foreign bodies and device for producing and/or processing a component made of metal or plastic

Info

Publication number: CN221713816U
Application number: CN202322625117.6U
Authority: CN
Inventors: 乌尔斯·赫尔丁; 弗朗茨·魏斯; 塞巴斯蒂安·丹多弗; 马提亚斯·卡默勒; 安娜·玛丽亚·赖默尔; 马克西米兰·罗施
Original assignee: Eldin Filtration Technology Co ltd
Current assignee: Eldin Filtration Technology Co ltd
Priority date: 2022-10-14
Filing date: 2023-09-27
Publication date: 2024-09-17
Anticipated expiration: 2033-09-27
Also published as: DE202022105823U1

Abstract

A filter device for cleaning a raw material gas carrying foreign matter and a device for manufacturing and/or processing a member made of metal or plastic, the filter device comprising: at least one filter element having a raw gas side facing the raw gas space and a clean gas side facing the clean gas space, the filter element being designed such that foreign matter carried in the raw gas is deposited on at least one filter surface facing the raw gas side when passing through the filter element; and at least one pressure pulse cleaning device designed to generate a cleaning pressure pulse for cleaning material deposited on the at least one filter element, and a pressure wave damping device designed to act on a fluid present in at least one volume in fluid communication with the raw gas and/or the cleaning gas and to generate a fluid disturbance counteracting pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulse.

Description

Filter device for cleaning a raw gas carrying foreign bodies and device for producing and/or processing a component made of metal or plastic

Technical Field

The present utility model relates to a filter device for cleaning a raw material gas carrying foreign substances, in particular in a closed system, in which exhaust gas from a processing environment is led to the filter device while being isolated from the outside or while being hermetically sealed from the outside, and if necessary, the cleaning gas cleaned by the filter device is returned to the processing environment.

Background

In certain processes, such as in systems for additive manufacturing of workpieces made of metal (for example, in selective laser sintering of workpieces made of titanium or aluminum alloys), exhaust gases are produced which have to be cleaned of particles by means of a filter device. The exhaust gases are led from the processing environment in which the work piece is built or processed to a filter device, generally while the exhaust gases are isolated from the outside. The filter device includes one or more filter elements disposed in a filter housing and separating a feed gas space from a clean gas space of the filter device. The particle-containing waste gas is fed into the raw gas space and, as it passes through the walls of the filter element, entrained foreign bodies are removed so that the particle-free waste gas reaches the clean gas side of the filter element facing the clean gas space. Typically, the cleaning gas is returned to the processing environment.

During operation, foreign matter carried in the exhaust gas (possibly together with added filter aid such as lime dust or silica) accumulates on the filter surface of the filter element facing the raw gas space. The deposited material forms a filter cake which is usually cleaned from time to time by means of a pressure pulse cleaning process. Applying pressure pulses to the filter element in a pulse-like manner associated with a pressure pulse cleaning cycle results in pressure changes in the feed gas space and the cleaning gas space of the filter device. These pressure variations may propagate into the processing environment in which the additive manufacturing occurs, thereby interfering with the manufacturing process occurring therein. It is therefore desirable to keep such pressure variations in the raw gas space and the clean gas space as small as possible and/or to allow them to occur only when no formation or processing of the workpiece to be manufactured is currently taking place, if possible.

Disclosure of utility model

The object of the present utility model is to further develop a filter device of the type mentioned so as to avoid as much as possible or at least suppress as much as possible the damaging effects on the formation of workpieces to be manufactured and/or processed (in particular by means of additive manufacturing) in a processing environment. This relates in particular to damaging pressure fluctuations in the process environment associated with the cleaning of the filter element that occurs from time to time.

For this purpose, according to the utility model, a filter device is proposed.

The filtering device for cleaning a raw material gas carrying foreign matters includes:

At least one filter element having a feed gas side facing the feed gas space and a clean gas side facing the clean gas space, the filter element being designed such that foreign matter entrained or carried in the feed gas is deposited on at least one filter surface facing the feed gas side as it passes through the filter element;

At least one pressure pulse cleaning device designed to generate cleaning pressure pulses for cleaning material deposited on the at least one filter element; and

A pressure wave damping device designed to act on a fluid present in at least one volume in fluid communication with the feed gas and/or the cleaning gas and to generate a fluid disturbance that counteracts pressure waves generated in the feed gas and/or the cleaning gas by the cleaning pressure pulses.

In particular, the pressure wave damping device may be designed to generate pressure variations as fluid disturbances in the fluid acted upon by the pressure wave damping device, which pressure variations counteract pressure waves generated by the cleaning pressure pulses in the raw gas and/or the cleaning gas. The pressure change may be a release of pressure in the fluid acted upon by the pressure wave damping device.

In particular, pressure changes in the fluid acted upon by the pressure wave damping means may generate counter pressure waves that counteract pressure waves triggered by the purge pressure pulses in the raw gas and/or the cleaning gas.

Additionally or alternatively, the pressure wave damping device may be designed to generate pressure variations as fluid disturbances in the fluid acted upon by the pressure wave damping device that counteract pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulses.

The expression generating a fluid disturbance that counteracts the pressure wave generated by the cleaning pressure pulse in the raw gas and/or the cleaning gas is intended to mean that by generating a fluid disturbance the pressure wave is attenuated or even counteracted before reaching the processing environment or processing space in which the raw gas carrying the foreign matter is generated, which pressure wave is triggered in the raw gas space and/or the cleaning gas space by the cleaning pressure pulse and which pressure wave can propagate in the flow direction of the raw gas carrying the foreign matter in the raw gas space and/or in a region upstream of the raw gas space or downstream of the cleaning gas space in the flow direction of the cleaning gas flowing out of the filter element. When the feed gas is directed from the process environment or process space to the feed gas space via the feed gas line or the cleaning gas is directed from the cleaning gas space to the process environment or process space, in these areas, in particular in the process environment or process space, a weakening or damping effect of the fluid disturbance generated by the pressure wave damping means on the pressure wave triggered by the cleaning pressure pulse occurs in any case.

When the purge pressure pulse is provided as an impulse-like or sudden pulse, without further measurement, the pressure change triggered by the purge pressure pulse will be a pulse-like pressure increase in the raw gas space and/or the cleaning gas space, which pulse-like pressure increase will propagate as a pressure wave into a region upstream of the raw gas space in the flow direction of the exhaust gas carrying the foreign matter and/or downstream of the cleaning gas space in the flow direction of the cleaning gas flowing out from the filter element. The pressure wave may remain time-limited and thus propagate as a multitude of pulse-shaped pressure waves or pressure shocks in the raw gas and/or the cleaning gas. In order to attenuate propagating or counteract such pressure waves, it is useful for pressure wave damping devices to create a pressure relief or pressure drop in the fluid acting thereon as a fluid disturbance. The pressure release or pressure drop should in particular correspond to a cleaning pressure pulse and in particular also be pulse-shaped, i.e. start suddenly and of short duration. In particular, the pressure release should take place in a time-coordinated manner with the generation of the cleaning pressure pulse. For example, the pressure wave damping device may act on fluid in a volume in fluid communication with the feed gas and/or the cleaning gas while triggering a purge pressure pulse.

The damping effect of the fluid disturbance generated by the pressure wave damping device on the pressure wave in the raw gas space and/or in the cleaning gas space, which is triggered by the cleaning pressure pulse, occurs in particular in the raw gas space and/or in the cleaning gas space and/or in a region which is located upstream of the raw gas space in the flow direction of the raw gas carrying the foreign bodies and/or downstream of the cleaning gas space in the flow direction of the cleaning gas.

In this way, it is possible to achieve an effective attenuation (ideally even suppression) of the total pressure change caused by the cleaning pressure pulse and the pressure wave damping means in the raw gas space and/or the cleaning gas space and/or in the region upstream of the raw gas space in the flow direction of the raw gas carrying the foreign matter and/or in the region downstream of the cleaning gas space in the flow direction of the cleaning gas, since the pressure changes caused by the cleaning pressure pulse and the pressure wave damping means are oriented in opposite directions to one another and ideally even cancel one another.

The term "pulsed" is intended to mean that the pressure increase or pressure release should have a pulsed temporal profile, in particular should occur suddenly. Thus, a strong pressure increase or pressure release will occur in a relatively short period of time. The time profile of the cleaning pressure pulse for cleaning can be selected as desired. In any case, however, the time profile of the fluid disturbance generated by the pressure wave damping means in the fluid acting in at least one volume of the filter means and the time profile of the pressure release triggered thereby are adapted to the correspondingly selected time profile of the cleaning pressure pulse. In particular, the cleaning pressure pulse and the fluid acting in the at least one volume should have coordinated and/or synchronized time profiles with respect to each other. For example, the cleaning pressure pulse and the action on the fluid in the at least one volume may occur simultaneously.

In a particular refinement of the filter device, the pressure wave damping device may comprise an accumulator which may be brought selectively into fluid communication with at least one volume in fluid communication with the feed gas in order to act on the fluid present in the volume and to generate a fluid disturbance.

The pressure wave damping device may be adapted to build up and/or store a counter pressure in the accumulator during normal operation. The pressure wave damping means may be further adapted to bring the accumulator into fluid contact with the fluid in the at least one volume in a manner that is time coordinated with the wash pressure pulses (e.g. simultaneously) so as to generate a fluid disturbance.

In particular, the pressure accumulator can be designed as a negative pressure or vacuum accumulator.

The term "negative pressure or vacuum" in this context refers to the pressure prevailing in the at least one volume during normal operation. Thus, a lower pressure is generated and stored in the vacuum accumulator than the pressure prevailing in the at least one volume during normal operation, i.e. when the vacuum accumulator is separated from the at least one volume. The greater the pressure differential between the vacuum accumulator and the volume, the greater the volume of the vacuum accumulator, and the greater the disturbance of the fluid when establishing fluid communication between the vacuum accumulator and the at least one volume, because the more fluid flows into the vacuum accumulator from the at least one volume until pressure equalization is established.

In an embodiment, the pressure wave damping device may be implemented by providing a vacuum accumulator, which may be brought into contact with at least one volume in fluid communication with the raw gas space and/or the raw gas line and/or the clean gas space and/or the clean gas line. By establishing fluid communication between the vacuum accumulator and the volume, a fluid disturbance is generated in the volume, as a result of which a pressure wave triggered by the purge pressure pulse in the raw gas and/or the purge gas is destroyed or in any case suppressed to such an extent that this pressure wave cannot propagate to the process space.

The damping effect created by establishing fluid communication between the vacuum accumulator and the volume in fluid communication with the feed gas and/or the cleaning gas may be based on various effects that may be considered as fluid disturbances, each of which may occur separately but also in combination with each other. For example, the fluid disturbance may be based on the following facts: when fluid communication is established between the vacuum accumulator and the volume in fluid communication with the raw material gas and/or the cleaning gas, a "counter pressure wave" is generated which propagates in the raw material gas and/or up to the cleaning gas and which when it interferes with the pressure wave triggered by the cleaning pressure pulse causes the two pressure waves to be largely cancelled out. Furthermore, the further damping effect may be caused by the fact that: after establishing fluid communication between the vacuum accumulator and the volume in fluid communication with the raw gas and/or the cleaning gas, fluid flows from this volume into the vacuum accumulator, thereby triggering temporary flows in the raw gas and/or the cleaning gas, which have a damping effect on the propagation of pressure waves in the raw gas and/or the cleaning gas. The generation of such a flow may be associated with pressure fluctuations in the volume and/or in the raw gas and/or in the cleaning gas.

In a particular embodiment, the pressure wave damping device may comprise a vacuum generator, in particular a vacuum pump, a vacuum ejector or a blower, by means of which a vacuum can be generated in the pressure accumulator.

The vacuum generator may be selectively coupleable to the accumulator at least in a state in which the accumulator is separated from the at least one volume so as to generate a vacuum in the accumulator.

In a further refinement, the accumulator may have associated therewith a closure member or valve separating the accumulator from at least one volume of the filter device, the valve being selectively controllable to establish and/or interrupt fluid communication between the accumulator and the at least one volume of the filter device. In this context, the term valve is intended to refer to any type of closure member that allows for selectively establishing fluid communication between an accumulator and a volume or preventing such fluid communication. Examples of such valves are rotary valves, slide valves, flaps, etc.

By establishing fluid communication between the accumulator and at least one volume of the filter device, pressure equalization is achieved between the fluid stored in the accumulator and the fluid present in the volume of the filter device. This pressure equalization is intended to cause fluid disturbances. In particular, the pressure equalization should be abrupt, i.e. have a timely large enough change to create a fluid disturbance.

Furthermore, the pressure accumulator may have means for venting to the environment. In particular, the overpressure side of the vacuum generator can be open to the environment or can be vented to the environment to release the overpressure, which is generated when a vacuum is generated in the pressure accumulator on the overpressure side of the vacuum generator as a counter pressure to suppress pressure waves triggered by the cleaning pressure pulses in the raw gas and/or the cleaning gas.

In further embodiments, the pressure wave damping device may comprise means for coupling with the pressure pulse cleaning device. In particular, the coupling is designed such that an overpressure generated when a vacuum is generated in the pressure accumulator can be used for the pressure pulse cleaning device for generating cleaning pressure pulses. For example, the overpressure side of the vacuum generator may be coupled to an accumulator of the pressure pulse cleaning device for generating cleaning pressure pulses.

Further, the pressure wave damping device and the pressure pulse cleaning device may be hermetically sealed from the environment.

The pressure wave damping means may be designed such that it acts on the fluid present in the raw gas space and generates a fluid disturbance that counteracts the pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulses.

Additionally or alternatively, the pressure wave damping means may be designed to act on the fluid present in the cleaning gas space and to generate a fluid disturbance that counteracts the pressure wave generated in the raw gas and/or the cleaning gas by the cleaning pressure pulse.

Additionally or alternatively, the pressure wave damping device may be designed to act on the fluid present in the raw gas line leading to the raw gas space and to generate a fluid disturbance counteracting the pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulses.

Additionally or alternatively, the pressure wave damping device may be designed to act on the fluid present in the cleaning gas line leading away from the cleaning gas space and to generate a fluid disturbance which counteracts the pressure wave generated in the raw gas and/or the cleaning gas by the cleaning pressure pulse.

In an embodiment, the feed gas originates in the process environment or process space and the filter means are designed to guide the feed gas from the process environment or process space to the filter element, the pressure wave damping means may additionally or alternatively be designed such that it acts on the fluid present in the process environment or process space and generates fluid disturbances which counteract pressure waves in the feed gas and/or cleaning gas generated by the cleaning pressure pulses.

In an embodiment, a discharge vessel is provided in which material falling from the filter element is collected after the filter element has been acted upon by a cleaning pressure pulse, the pressure wave damping device may additionally or alternatively be designed such that it acts on the fluid present in the discharge vessel and generates a fluid disturbance which counteracts the pressure wave generated in the raw gas and/or cleaning gas by the cleaning pressure pulse.

It is explicitly pointed out that the above arrangements, in which the fluid is acted upon by the pressure wave damping means in the volume associated with the fluid in the raw gas space, the clean gas space, the raw gas line, the clean gas line, the process space or the discharge vessel, can be combined with each other in any way, if desired. It is therefore easily conceivable that the pressure wave damping device is designed to act on the fluid in both the volume associated with the discharge vessel and the volume associated with the cleaning gas line. Similarly, it is conceivable that the pressure wave damping device is configured to act on the fluid in both the volume associated with the raw gas space and the volume associated with the cleaning gas line.

In a further embodiment, the pressure purging device and the pressure wave damping device may be designed such that the generation of the respective cleaning pressure pulses for cleaning the material deposited on the at least one filter element and the action on the fluid present in the at least one volume in fluid communication with the feed gas for generating a fluid disturbance that counteracts the pressure wave generated in the feed gas and/or the cleaning gas by the cleaning pressure pulses are performed in a time-coordinated manner, in particular simultaneously.

The filter device according to the utility model can be used in devices for producing and/or processing components made of metal or plastic, in particular by means of additive manufacturing processes or 3D printing processes, such as selective laser sintering, selective laser melting, electron beam melting, laser deposition welding, stereolithography, adhesive spraying or fused deposition modeling. The device comprises: a processing environment in which the component is processed and/or manufactured, and a filter device of the type described above. The filter device is then coupled to the process environment in a closed loop such that the feed gas is directed from the process environment to the filter element via the feed gas line and the clean gas flowing from the filter element is directed back to the process environment. Advantageously, the processing environment and the filtration device are hermetically sealed from the environment.

Drawings

The utility model will be explained in more detail below by means of alternative specific embodiments with reference to the accompanying drawings showing different embodiments according to the subject matter of the utility model:

Fig. 1A shows a first embodiment in which the vacuum generator is vented to the environment and acted upon by pressure wave damping means on the fluid present in the feed gas space.

Fig. 1B shows a second embodiment in which the vacuum generator is vented to the environment and acted upon by pressure wave damping means on the fluid present in the feed gas space.

Fig. 1C shows a third embodiment, in which the vacuum generator is vented to the environment and acted upon by pressure wave damping means on the fluid present in the clean gas space.

Fig. 1D shows a fourth embodiment in which the vacuum generator is vented to the environment and acted upon by pressure wave damping means on the fluid present in the cleaning gas line.

Fig. 1E shows a fifth embodiment, in which the vacuum generator is vented to the environment and acted upon by pressure wave damping means on the fluid present in the feed gas line.

Fig. 1F shows a sixth embodiment in which the vacuum generator is vented to the environment and acted upon by pressure wave damping means on the fluid present in the processing environment.

Fig. 1G shows a seventh embodiment, in which the vacuum generator is vented to the environment and acted upon by pressure wave damping means on the fluid present in the raw gas line and the fluid present in the clean gas line.

Fig. 2A shows an eighth embodiment, wherein a vacuum generator is coupled to the pressure pulse cleaning device and acted upon by the pressure wave damping device on the fluid present in the feed gas space.

Fig. 2B shows a ninth embodiment, in which a vacuum generator is coupled to the pressure pulse cleaning device and acted upon by the pressure wave damping device on the fluid present in the feed gas space.

Fig. 2C shows a tenth embodiment, wherein a vacuum generator is coupled to the pressure pulse cleaning device and acted upon by the pressure wave damping device on the fluid present in the cleaning gas space.

Fig. 2D shows an eleventh embodiment, wherein a vacuum generator is coupled to the pressure pulse cleaning device and acted upon by the pressure wave damping device on the fluid present in the cleaning gas line.

Fig. 2E shows a twelfth embodiment, in which a vacuum generator is coupled to the pressure pulse cleaning device and acted upon by the pressure wave damping device on the fluid present in the feed gas line.

Fig. 2F shows a thirteenth embodiment, wherein a vacuum generator is coupled to the pressure pulse cleaning device and acted upon by the pressure wave damping device on the fluid present in the processing environment.

Fig. 2G shows a fourteenth embodiment, in which a vacuum generator is coupled to the pressure pulse cleaning device and acted upon by pressure wave damping means on the fluid present in the raw gas line and the fluid present in the cleaning gas line.

Fig. 3A shows a fifteenth embodiment, in which the evacuation of the vacuum generator to the environment and the coupling of the vacuum generator to the pressure pulse cleaning device are combined and acted upon by the pressure wave damping device on the fluid present in the raw gas space.

Fig. 3B shows a sixteenth embodiment, wherein the evacuation of the vacuum generator to the environment and the coupling of the vacuum generator to the pressure pulse cleaning device are combined and acted upon by the pressure wave damping device on the fluid present in the raw gas space.

Fig. 3C shows a seventeenth embodiment, wherein the evacuation of the vacuum generator to the environment and the coupling of the vacuum generator to the pressure pulse cleaning device are combined and acted upon by the pressure wave damping device on the fluid present in the cleaning gas space.

Fig. 3D shows an eighteenth embodiment, wherein the evacuation of the vacuum generator to the environment and the coupling of the vacuum generator to the pressure pulse cleaning device are combined and acted upon by the pressure wave damping device on the fluid present in the cleaning gas line.

Fig. 3E shows a nineteenth embodiment, in which the evacuation of the vacuum generator to the environment and the coupling of the vacuum generator to the pressure pulse cleaning device are combined and acted upon by the pressure wave damping device on the fluid present in the raw gas line.

Fig. 3F shows a twentieth embodiment, wherein the evacuation of the vacuum generator to the environment and the coupling of the vacuum generator to the pressure pulse cleaning device are combined and acted upon by the pressure wave damping device on the fluid present in the processing environment.

Fig. 3G shows a twenty-first embodiment, in which the evacuation of the vacuum generator to the environment and the coupling of the vacuum generator to the pressure pulse cleaning device are combined and acted upon by the pressure wave damping device on the fluid present in the raw gas line and the fluid present in the cleaning gas line.

Detailed Description

In the following description of the various embodiments according to fig. 1A to 3G, identical or corresponding parts are each given the same reference numerals. To avoid repetition, each component is described only once in each case, with reference to the first drawing in which it is included. For a description of these components in the various subsequent figures, reference is made to the various figures of the component which are described in detail and which are applied in the same manner.

Fig. 1A shows an apparatus for manufacturing or processing a workpiece by means of additive manufacturing, which apparatus comprises a filter apparatus 10 according to a first embodiment. In the filter device 10 according to fig. 1A, the negative pressure or vacuum generator is vented to the environment. In order to act on the fluid present in the raw gas space, the pressure wave damping device has a vacuum accumulator, which can be in fluid communication with the raw gas space.

Fig. 1A shows a highly simplified side sectional view of a filter device 10, which has, as an example, six filter elements 14 arranged in parallel and a pressure pulse cleaning device 16. The filter device 10 comprises a filter housing 12 extending from a bottom side to a top side, wherein six filter elements 14 are arranged spaced apart from each other and parallel to each other. On the right side of the filter housing 12 in fig. 1, the filter housing has a raw material gas inlet 18 at the bottom for a gas (hereinafter referred to as raw material gas) carrying or entraining foreign matter to be cleaned. Above the raw material gas inlet 18, on the right side of fig. 1, there is a clean gas outlet 20 for raw material gas (hereinafter referred to as clean gas) filtered after passing through the filter element 14. The filter element 14 is attached or suspended to a baffle structure, in particular a baffle 22, which is arranged near the top side in the filter housing 12 and protrudes vertically into the raw gas space 24. The partition 20 divides the filter device 10 or the filter housing 12 into a raw gas space 24 and a clean gas space 26, the raw gas space 24 being located on the side of the partition 22 and the filter element 14 facing the raw gas inlet 18, and the clean gas space 26 being located on the side of the partition 22 and the filter element 14 facing the clean gas outlet 20.

In the embodiment shown in fig. 1A, the filter element 14 has a box-like shape with four side surfaces extending between a top side and a bottom side, two of which are formed as opposite long sides, and two of which are formed as equally opposite narrow sides connecting the two long sides at right angles. Other shapes of the filter element are conceivable, such as a cylindrical filter element.

The filter element 14 is inherently stable. It follows that the filter element 14 is made of a material that is sufficiently rigid to be able to support the filter element 14 in a dimensionally stable manner without the aid of other support structures. It is conceivable to use other filter elements that are not inherently stable, i.e. in which a separate support structure is required to support the components of the filter element that serve as filter media. The inherently stable filter element 14 shown in fig. 1A may be made of a sintered plastic material, such as sintered polyethylene or sintered polyphenylene sulfide.

The arrangement of the feed gas space 24, the clean gas space 26, and the filter element 14 in fig. 1A is merely exemplary, and any other arrangement may be selected. For example, the locations of the feed gas space 24 and the clean gas space 26 may be interchanged such that the filter element 14 protrudes into the clean gas space 26. Instead of the arrangement of the filter element 14 shown, with a support on a horizontally extending partition 22 and a main extension in the vertical direction, the filter element 14 can also be supported on a partition extending in the vertical direction and have their main direction extend horizontally. The feed gas space will then be on one side of the partition (left or right in the filter housing in fig. 1A) and the clean gas space will be on the other side of the partition (right or left in the filter housing in fig. 1A).

Another embodiment (not shown) may have a feed gas inlet and a clean gas outlet on two opposite sidewalls of the filter housing. The feed gas inlet and the cleaning gas outlet may also be arranged in any combination of the possibilities mentioned above.

During operation of the device, feed gas to be filtered passes from the feed gas line 28 through the feed gas inlet 18 into the feed gas space 24 and then through the porous side wall of a respective one of the filter elements 14 from its feed gas side into the interior space on the clean gas side, which is closed by the side wall of the respective filter element 14. From there, the cleaning gas passes through a flow opening in the top of the filter element 14 into the cleaning gas space 26, from where it is discharged back to the outside of the filter device 10 through the cleaning gas outlet 20 via the cleaning gas line 30.

A blower 32 for conveying the cleaning gas is disposed in the cleaning gas line 30. The clean gas line 32 leads to a process space or process environment 34. The process space or process environment 34 is also enclosed by the housing, thus, similar to the filter housing 12, creating a space isolated from the environment. It should be noted that in embodiments where the process space is open to its environment, pressure wave damping devices of the type suggested herein may alternatively be provided. The embodiments described in more detail herein with reference to the enclosed process space may then be similarly applied to a process space that is open to its environment, or in any case not completely hermetically sealed. In the processing space 34, there is an arrangement for manufacturing and/or processing a workpiece by means of an additive manufacturing process or a 3D printing process, such as selective laser sintering, selective laser melting, electron beam melting, laser deposition welding, stereolithography, adhesive spraying or fused deposition modeling. During operation of the arrangement for manufacturing and/or machining a workpiece, an exhaust gas carrying foreign matter is generated in the machining space 34, which then in turn is conducted as a raw gas through the raw gas line 28 leading from the machining space or the machining environment 34 to the filter device 10 for removing foreign matter from the exhaust gas. Thus, the filter device 10 and the process space or process environment 34 together with the raw gas line 28, the clean gas line 30 form a system that is hermetically sealed from the environment. It should again be pointed out that the corresponding explanation applies if there is a working space which is open to its environment or in any case not completely hermetically sealed.

In the filtering device 10, foreign substances/substances to be separated from the raw material gas are retained by a fine porous coating layer (not shown) on the surface of the filtering element 14 on the raw material gas-facing side and remain partially adhered thereto. Such adhered solid particle layers are sprayed in cleaning cycles repeated at intervals, for example by applying a cleaning pressure pulse to the filter element 14 in a direction opposite to the flow direction of the gas to be cleaned, and lowered to the bottom of the filter housing 12 on the raw gas side of the filter element 14.

The pressure pulses for cleaning the filter element 14 are generated by a pressure pulse cleaning device 16. The pressure pulse cleaning device 16 is arranged on the clean gas side of the filter element 14 and comprises a pressurized gas accumulator 42, a plurality of pressurized gas nozzles 44 being arranged in the pressurized gas accumulator 42. The pressurized gas accumulator 42 communicates with a pressurized gas supply 46 (not shown in detail in fig. 1A) via a shut-off valve 48. In the exemplary embodiment shown in fig. 1A, each pressurized gas nozzle 44 is arranged in the clean gas space 26 such that it faces a respective flow-through opening in the top of one of the filter elements 14, and thus a cleaning pressure pulse may be applied to the side wall of the filter element 14 from the clean gas side.

It should be noted that the arrangement of the pressure pulse cleaning device 16 shown in fig. 1A, in particular with respect to the arrangement of the pressurized gas nozzles 44, is merely exemplary, and that pressure pulse cleaning devices having different configurations are also conceivable. If the process environment allows for the introduction of an oxygen-containing gas, air may be used as the pressurized gas. In many cases it will be important to keep the oxygen content of the processing environment as low as possible or at least below a certain critical threshold. In this case, an inert gas such as nitrogen or a rare gas may be used as the pressurizing gas.

The lower part of the filter housing 12 is funnel-shaped and the discharge opening 36 for filtered material is located at the lowest point of the funnel. The discharge opening 36 is closed by a closing member 38, such as a closing valve.

Below the closing member 38, the discharge container 40 is connected via a discharge channel 42. When the closure member 38 is open, material collected at the bottom of the filter housing 12 may be delivered into the drain receptacle 40 via the drain channel 42. In the simplest case, this can be done by gravity, as shown in fig. 1A. If desired, an active delivery system may also be provided that enables or at least facilitates the delivery of material from the feed gas space 24 through the discharge channel 42 into the discharge vessel 40, such as a screw system and/or fluidization means.

The pressure pulses generated by the pressure pulse cleaning device 16 for cleaning the filter element 14 act not only on the side walls of the filter element 14, but also each cleaning pressure pulse also results in the generation of pressure waves in the raw gas and/or cleaning gas in the raw gas space 24 and/or cleaning gas space 26, which pressure waves correspond to the cleaning pressure pulses. The pressure wave also has a pulse-like configuration and propagates into the feed gas space 24 from the region of the feed gas space 24 adjacent the filter element 14 and into the clean gas space 26 from the region of the clean gas space 26 adjacent the filter element 14. The pressure wave passes from the feed gas space 24 to a region further upstream, such as the feed gas line 28 and even the process space 34. In addition, since the pressure wave can also pass through the filter element 14, the pressure wave and the cleaning gas diffuse into the cleaning gas space 26 and can also enter the process space 34 from the cleaning gas space via the cleaning gas line 30.

For certain processes to occur in the process space 34, it is important to maintain as constant a pressure as possible in the process space 34. This is the case, for example, in many processes for manufacturing and/or processing workpieces by means of additive manufacturing processes or 3D printing processes, such as selective laser sintering, selective laser melting, electron beam melting, laser deposition welding, stereolithography, adhesive spraying or fused deposition modeling. As a result, efforts should be made to suppress as much as possible the effects of the pressure waves triggered by the repeated cleaning pressure pulses of the filter device 10, so that these pressure waves are no longer significantly present, at least in the process space 34.

In order to suppress pressure waves triggered by repeated cleaning pressure pulses of the filter device 10, the filter device 10 has a pressure wave damping device, which is generally indicated by reference numeral 50 in fig. 1A. The pressure wave damping device 50 comprises a vacuum generator 52, which is designed, for example, as a vacuum pump, a vacuum ejector or a blower, a vacuum accumulator 54, a shut-off member or valve 56, a vacuum line 58, a filter 60 and a ventilation outlet 62. In the embodiment shown in fig. 1A, the pressure wave damping device is configured such that the upper part of the discharge vessel 40, which is not filled with cleaning material, and the discharge channel 42 simultaneously serve as a vacuum accumulator 54 of the pressure wave damping device 50. Furthermore, the closing member or valve 38 of the discharge opening 36 of the filter housing 12 simultaneously serves as a closing member or valve 56 of a pressure wave damping device which, in the closed configuration, separates the vacuum accumulator 54 from the fluid (raw gas) present in the raw gas space 24.

During normal operation of the filter apparatus 10, the closure element or valve 38/54 remains closed. The vacuum generator 52 generates a predetermined vacuum in the vacuum accumulator 54, which is formed by the upper part of the discharge vessel 40 and the discharge channel 42. Fluid (gas) pumped from the vacuum accumulator 54 is discharged to the environment through a vent outlet 62. To prevent particulate matter from entering the environment, a filter 58 is provided in the vacuum line 58. Once a predetermined negative pressure or vacuum is reached in the vacuum accumulator 54 relative to the pressure prevailing in the raw gas space 24, the vacuum generator 52 stops or reduces its pumping power to such an extent that only a predetermined negative pressure is maintained in the vacuum accumulator 54.

Once a cleaning cycle of one or more of the filter elements 14 is about to begin, the closure element or valve 38/56 is also opened simultaneously with the generation of a cleaning pressure pulse acting on the respective filter element 14 or the cleaning pressure pulses acting on the plurality of respective filter elements 14. On the one hand, this results in that material falling from the filter element 14 can fall directly into the discharge container 40. On the other hand, however, this also has the following effect: pressure equalization occurs between the fluid (gas) stored in the vacuum accumulator 54 and the raw gas present in the raw gas space 24. The pressure equalization is mainly accompanied by a sudden start of the flow of the raw gas from the raw gas space 24 into the vacuum accumulator 54, as a result of which a counter pressure wave is triggered in the raw gas space 24, which counter pressure wave also propagates in the raw gas space 24 and is superimposed on the pressure wave triggered by the cleaning pressure pulse. In addition, a flow is also generated in the raw gas space 24, which continues until a pressure equalization is achieved between the vacuum accumulator 54 and the raw gas space 24. This flow has a strong damping effect on the propagation of pressure waves and thus prevents the pressure waves triggered by the purge pressure pulse in the raw gas space 24 from propagating into the upstream region of the raw gas space 24 (in particular into the raw gas line 28) or into the region downstream of the clean gas space 26 on the clean gas side of the filter element 14 (in particular in the clean gas line 30). In this way, it is achieved that in the process space 34 there is hardly any significant influence on the pressure prevailing therein by the cleaning cycle occurring in the filter device 10 in which the filter element 14 is acted upon by the cleaning pressure pulses.

After the cleaning cycle is completed, i.e. when a pressure equalization has taken place between the raw gas space 24 and the vacuum accumulator 54, the shut-off valve 56 is closed again and the vacuum generator 52 again builds up a predetermined vacuum pressure in the vacuum accumulator 54. Once the predetermined vacuum pressure in the vacuum accumulator 54 has been reached, a new cleaning cycle may begin with the application of cleaning pressure pulses to each filter element 14 to be cleaned.

The configuration of the pressure wave damping device 50 according to fig. 1A has the advantage that only few additional components are required. In particular, components may be used for both the vacuum accumulator 54 and the shut-off valve 56, which components are in any case provided as the discharge channel 42 for the discharge opening, the discharge vessel 40 and the shut-off valve 38.

In the filter device 10 according to fig. 1B, the vacuum generator 52 is also vented to the environment. In order to act on the fluid present in the raw gas space 24, the pressure wave damping device 50 in fig. 1B has a separate vacuum accumulator 54, which vacuum accumulator 54 can be brought into fluid communication with the raw gas space 24 by opening a separate shut-off valve 56 in order to attenuate or even suppress the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse.

In addition, the same applies to fig. 1B as described with reference to fig. 1A.

In the filter device 10 according to fig. 1C, the evacuation of the vacuum generator 52 also takes place in the environment. In contrast to fig. 1A and 1B, the pressure wave damping device 50 in fig. 1C acts on the fluid (cleaning gas) present in the cleaning gas space 26 in order to attenuate or even counteract the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse before it reaches the process space 34. In order to act on the fluid present in the cleaning gas space 26, the pressure wave damping device 50 in fig. 1C has a separate vacuum accumulator 54, which vacuum accumulator 54 can be brought into fluid communication with the cleaning gas space 24 by opening a separate shut-off valve 56 in order to attenuate or even suppress the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse. In this variant, it is not necessary to provide an additional filter in the vacuum line 58, since the vacuum line 58 leads on the clean gas side to the filter device 10.

In addition, the same applies to fig. 1C as described with reference to fig. 1A and 1B.

In the filter device 10 according to fig. 1D, the vacuum generator 52 is also vented to the environment. In contrast to fig. 1A, the pressure wave damping device 50 in fig. 1D acts on the fluid (cleaning gas) present in the cleaning gas line 30 in order to attenuate or even counteract the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse before it reaches the process space 34. In fig. 1D, in order to act on the fluid present in the cleaning gas line 30, the pressure wave damping device 50 has a separate vacuum accumulator 54, which vacuum accumulator 54 can be brought into fluid communication with the cleaning gas space 24 by opening a separate shut-off valve 56 in order to attenuate or even suppress the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse. In this variant, it is not necessary to provide an additional filter in the vacuum line 58, since the vacuum line 58 leads to the filter device 10 on the clean gas side.

In addition, the same applies to fig. 1D as described with reference to fig. 1A to 1C.

In the filter device 10 according to fig. 1E, the evacuation of the vacuum generator 52 also takes place in the environment. In contrast to fig. 1A, the pressure wave damping device 50 in fig. 1E acts on the fluid (raw gas) present in the raw gas line 28 in order to attenuate or even counteract the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse before it reaches the processing space 34. In fig. 1E, to act on the fluid in the feed gas line 28, the pressure wave damping device 50 comprises a separate vacuum accumulator 54, which vacuum accumulator 54 can be brought into fluid communication with the feed gas line 28 by opening a separate shut-off valve 56 to attenuate or even suppress the pressure wave triggered in the feed gas space 24 by the purge pressure pulse. An additional filter 60 in the vacuum line 58 is provided to prevent unfiltered feed gas from escaping through the vacuum line 58 to the environment.

In addition, the same applies to fig. 1E as described with reference to fig. 1A to 1D.

In the filter device 10 according to fig. 1F, the vacuum generator 52 is also vented to the environment. In contrast to fig. 1A, the pressure wave damping device 50 in fig. 1F acts on the fluid present in the process space 34 in order to attenuate or even counteract the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse before it reaches the process space 34. In fig. 1F, in order to act on the fluid present in the process space 34, the pressure wave damping device 50 comprises a separate vacuum accumulator 54, which vacuum accumulator 54 can be placed in fluid communication with the process space 34 by opening a separate shut-off valve 56 to attenuate or even suppress the pressure wave triggered in the raw gas space 24 by the purge pressure pulse. An additional filter 60 in the vacuum line 58 is provided to prevent unfiltered raw gas from escaping from the process space 34 into the environment via the vacuum line 58.

In addition, what has been described with reference to fig. 1A to 1E applies equally to fig. 1F.

In the filter device 10 according to fig. 1G, the vacuum generator 52 is also vented to the environment. As with the embodiment according to fig. 1A, the pressure wave damping device 50 is configured such that the upper part of the discharge vessel 40, which is not filled with cleaning material, and the discharge channel 42 simultaneously serve as a first vacuum accumulator 54A of the pressure wave damping device 50. Furthermore, the shut-off valve 38 of the discharge opening 36 of the filter housing 12 simultaneously serves as a first shut-off valve 56A of the pressure wave damping device 50, which in the closed configuration separates the first vacuum accumulator 54A from the fluid (raw gas) present in the raw gas space 24. The additional filter 60A in the vacuum line 58A is to prevent unfiltered raw gas from escaping from the raw gas space 24 or the vent channel 42 into the environment via the first negative pressure line 58A. In contrast to fig. 1A, the pressure wave damping device 50 in fig. 1G additionally acts on the fluid (cleaning gas) present in the cleaning gas line 30 in order to attenuate or even counteract the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse before it reaches the process space 34. In fig. 1G, for further action on the fluid present in the cleaning gas line 30, the pressure wave damping device 50 has a second separate vacuum accumulator 54B which can be brought into fluid communication with the cleaning gas line 30 by opening a second separate shut-off valve 56B in order to attenuate or even suppress the pressure wave triggered in the raw gas space 24 by the cleaning pressure pulse. Because the second vacuum line 58B leads to the clean gas line 30, additional filters in the second vacuum line 58B are again unnecessary. The combined effect of the fluid present in the feed gas space 24 (feed gas) and the fluid present in the purge gas line 30 (purge gas) is particularly effective in suppressing pressure waves triggered in the feed gas by purge pressure pulses. A third separate shut-off valve 64A in the first vacuum line 58A allows the vacuum generator 52 to be disconnected from the first vacuum line 58A, thus allowing only the second vacuum line 58B to be used to act on the fluid in the cleaning gas line 30.

In addition, what has been described with reference to fig. 1A to 1F applies equally to fig. 1G.

In the filter device 10 according to fig. 2A to 2G, the evacuation of the vacuum generator 52 does not take place in the environment. Conversely, the outlet 62 on the overpressure side of the vacuum generator 52 is coupled to the inlet of the accumulator 42 of the pressure pulse cleaning device 16. In this way, the fluid delivered by the vacuum generator 52 to create a predetermined vacuum in the vacuum accumulator 54 can be readily used to create the necessary overpressure in the accumulator 42 of the pressure pulse cleaning device 16.

In addition, the same applies to each of fig. 2A to 2G as described with reference to fig. 1A to 1G.

With the filter device 10 according to fig. 3A to 3G, there is the possibility of optionally venting the vacuum generator 52 to the environment or coupling the outlet 62 on the overpressure side of the vacuum generator 52 to the inlet of the accumulator 42 of the pressure pulse cleaning device 16. In this way, if desired, the fluid delivered by the vacuum generator 52 may be used to create a predetermined vacuum in the vacuum accumulator 54 in order to establish the necessary overpressure in the accumulator 42 of the pressure pulse cleaning apparatus 16. Alternatively, the outlet 62 on the overpressure side of the vacuum generator 52 may be connected to the environment to discharge the pumped fluid to the environment. For this purpose, the outlet 62 is followed by a three-way valve 68, the position of which can be used to select the appropriate fluid flow to the environment or accumulator 42. Furthermore, the accumulator 42 may be connected to the pressurized gas reservoir 44 via a closing element or valve 48 in order to set a suitable pressure in the accumulator 42.

In addition, the contents described with reference to fig. 1A to 1G and fig. 2A to 2G are equally applicable to each of fig. 3A to 3G.

Claims

1. A filtering device (10) for cleaning a raw material gas carrying foreign matter, characterized in that the filtering device comprises:

At least one filter element (14) having a raw gas side facing a raw gas space (24) and a clean gas side facing a clean gas space (26), the filter element (14) being designed such that foreign matter carried in the raw gas is deposited on at least one filter surface facing the raw gas side when passing through the filter element (14); and

At least one pressure pulse cleaning device (16) designed to generate cleaning pressure pulses for cleaning material deposited on the at least one filter element (14), and

A pressure wave damping device (50) designed to act on a fluid present in at least one volume in fluid communication with the raw gas and/or the cleaning gas and to generate a fluid disturbance counteracting pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulses.

2. The filter device (10) according to claim 1,

Characterized in that the pressure wave damping device (50) is designed to generate a pressure change as a fluid disturbance in the fluid acted upon by the pressure wave damping device (50), which counteracts the pressure wave generated by the cleaning pressure pulse in the raw gas and/or the cleaning gas.

3. The filter device (10) according to claim 2,

Characterized in that said pressure change is a pressure release in said fluid acted upon by said pressure wave damping means (50).

4. A filter device (10) according to claim 2 or 3,

Characterized in that the pressure change in the fluid acted upon by the pressure wave damping means (50) is a counter pressure wave which counteracts the pressure wave triggered by the purge pressure pulse in the raw gas and/or the cleaning gas.

5. A filter device (10) according to any one of claims 1 to 3,

6. The filter device (10) according to claim 1,

Characterized in that said pressure wave damping means (50) comprises an accumulator (54) which can be selectively brought into fluid communication with said at least one volume in fluid communication with said feed gas so as to act on the fluid present in said volume and produce said fluid disturbance.

7. The filter device (10) according to claim 6,

Characterized in that the pressure accumulator (54) is designed as a vacuum accumulator.

8. The filter device (10) according to claim 7,

Characterized in that the pressure wave damping device (50) comprises a vacuum generator (52) by means of which a vacuum can be generated in the pressure accumulator (54).

9. The filter device (10) according to claim 8,

The vacuum generator (52) is a vacuum pump, a blower or a vacuum ejector.

10. The filter device (10) according to any one of claims 6 to 9,

Characterized in that the pressure accumulator (54) has a closing member or valve (56) associated with the pressure accumulator, which separates the pressure accumulator (54) from the at least one volume of the filter device (10), wherein the closing member or valve (56) is selectively controllable to establish and/or interrupt fluid communication between the pressure accumulator (54) and the at least one volume of the filter device (10).

11. The filter device (10) according to any one of claims 6 to 9,

Characterized in that the accumulator (54) comprises means for venting to the environment.

12. The filter device (10) according to any one of claims 6 to 9,

Characterized in that said pressure wave damping means (50) comprise means for coupling with said pressure pulse cleaning means (16).

13. A filter device (10) according to any one of claims 1 to 3,

Characterized in that the pressure wave damping device (50) and the pressure pulse cleaning device (16) are hermetically sealed from the environment of the pressure wave damping device and the pressure pulse cleaning device.

14. A filter device (10) according to any one of claims 1 to 3,

Characterized in that the pressure wave damping device (50) is designed such that it acts on the fluid present in the raw gas space (24) and generates a fluid disturbance that counteracts the pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulses.

15. A filter device (10) according to any one of claims 1 to 3,

Characterized in that the pressure wave damping device (50) is designed such that it acts on the fluid present in the cleaning gas space (26) and generates a fluid disturbance that counteracts the pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulses.

16. A filter device (10) according to any one of claims 1 to 3,

Characterized in that the pressure wave damping device (50) is designed such that it acts on the fluid present in the raw gas line (28) leading to the raw gas space (24) and generates a fluid disturbance which counteracts the pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulses.

17. A filter device (10) according to any one of claims 1 to 3,

Characterized in that the pressure wave damping device (50) is designed such that it acts on the fluid present in the cleaning gas line (30) leading away from the cleaning gas space (26) and generates a fluid disturbance which counteracts the pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulses.

18. A filter device (10) according to any one of claims 1 to 3,

Characterized in that the feed gas is generated in a process environment or a process space (34) and the filter device (10) is designed to guide the feed gas from the process environment or the process space (34) to the at least one filter element (14), and wherein the pressure wave damping device (50) is designed such that it acts on a fluid present in the process environment or the process space (34) and generates a fluid disturbance that counteracts pressure waves generated in the feed gas and/or the cleaning gas by the cleaning pressure pulses.

19. A filter device (10) according to any one of claims 1 to 3,

Characterized in that a discharge vessel (40) is provided in which material falling from the at least one filter element (14) is collected after having been acted on the filter element (14) by the cleaning pressure pulse, and in that the pressure wave damping device (50) is designed such that it acts on the fluid present in the discharge vessel (40) and generates a fluid disturbance that counteracts pressure waves generated in the raw gas and/or the cleaning gas by the cleaning pressure pulse.

20. A filter device (10) according to any one of claims 1 to 3,

Characterized in that the pressure pulse cleaning device (16) and the pressure wave damping device (50) are designed such that the generation of a respective cleaning pressure pulse for cleaning material deposited on the at least one filter element (14) and the action on a fluid present in the at least one volume in fluid communication with the feed gas and/or the cleaning gas for generating a fluid disturbance that counteracts pressure waves generated in the feed gas and/or the cleaning gas by the cleaning pressure pulse are performed in a time-coordinated manner.

21. The filter device (10) according to claim 20,

Characterized in that the pressure pulse cleaning device (16) and the pressure wave damping device (50) are designed such that the generation of a respective cleaning pressure pulse for cleaning material deposited on the at least one filter element (14) and the action on a fluid present in the at least one volume in fluid communication with the raw gas and/or the cleaning gas for generating a fluid disturbance are performed simultaneously.

22. An apparatus for manufacturing and/or processing a component made of metal or plastic, the apparatus comprising:

A processing environment or processing space (34), in which the component is manufactured and/or processed, and

The filter device (10) according to any one of claims 1 to 21,

Characterized in that the filter device (10) is coupled to the processing environment or the processing space (34) in a closed circuit such that the raw gas is guided from the processing environment or the processing space (34) to the at least one filter element (14) via a raw gas line (28), and the clean gas flowing out of the at least one filter element (14) is guided back to the processing environment or the processing space (34).

23. An apparatus according to claim 22,

Characterized in that the device manufactures and/or processes the component by means of an additive manufacturing process or a 3D printing process.

24. The apparatus according to claim 23,

The additive manufacturing process or the 3D printing process is characterized by comprising selective laser sintering, selective laser melting, electron beam melting, laser deposition welding, stereolithography, adhesive spraying or fused deposition molding.