Filterpatrone

Abstract

Filter cartridge, in particular for dust measuring instruments or the like, with a housing (2) and with filter material arranged in the housing (2), characterized in that the one-piece filter housing (2) is designed as a cylindrical plug-in housing with a base (7) provided with openings (8-10) and a smooth rim (4) opposite the base (7) and that below the rim (4) an inwardly pointing circumferential nose (5) is formed which forms a stop with an annular shoulder (6) when the filter cartridge is plugged onto a tube.

Description

[0001] The invention relates to a filter cartridge, in particular for dust measuring devices or the like, with a housing and with filter material arranged in the housing.

[0002] In 2010, the first ordinance implementing the Federal Immission Control Act, the Ordinance on Small and Medium-Sized Combustion Plants (1.BImSchV), was amended to make a significant contribution to reducing particulate matter emissions from small combustion plants. In particular, the use of wood in combustion plants within the scope of the Ordinance on Small and Medium-Sized Combustion Plants can make an important contribution to achieving climate protection goals. However, the combustion of biomass can lead to emissions that are hazardous to health, including particulate matter, through the release of various air pollutants.

[0003] In order to achieve the climate targets, the 1st BImSchV requires regular monitoring of combustion plants and prescribes maximum values ​​for the particulate matter content in the exhaust gas, depending on the type of combustion plant.

[0004] For newer combustion plants, these limit values ​​will be 0.02 g / m³ from 2015 onwards. 3 These limit values ​​certainly pose a challenge for measurement technology, although the basic principle is simple and unchanged: to pass a predetermined quantity of exhaust gas from a combustion plant through a filter and to determine the mass difference before and after the measurement process in order to determine the particulate matter content in the exhaust gas.

[0005] The resulting requirements for a filter are manifold. First, the filter must be resistant to the potentially aggressive exhaust gases from combustion plants. High demands are also placed on the filter's performance, as the exhaust gases, particularly from solid-fuel combustion plants, contain not only the fine dust to be filtered out, but also coarse particles that must not clog the filter. Since a dust-laden filter cartridge generally cannot be used for further measurements, the filter cartridge must also be cost-effective and easy to handle for quick replacement. Depending on the weighing method, the filter cartridge must also be very lightweight and temperature-stable.

[0006] In a filter device known from WO 02 / 087 771 A1, a bottom is formed in the direction of flow by an inserted grid. For this purpose, the housing of the filter device has an inwardly projecting flange at its edge, which holds the grid and thus also the filter material within the housing. The filter device is further secured there with a union nut, for which the housing of the filter device is provided with an external thread and, in addition, with a radially outwardly projecting flange. This flange corresponds to a radially inwardly projecting flange of the union nut. Furthermore, the union nut must also be connected to the housing device so that the filter device can be secured to it.

[0007] A complex and expensive solution. Furthermore, this solution is not very user-friendly, as care must be taken to ensure that the filter elements do not fall out when the filter housing is secured.

[0008] Against this technical background, a filter cartridge, in particular for dust measuring instruments or the like, with a housing and with filter material arranged in the housing, is proposed, wherein according to claim 1 the one-piece filter housing is designed as a cylindrical plug-in housing with a perforated bottom and a smooth rim opposite the bottom, and wherein an inwardly pointing, circumferential nose is formed below the rim, which forms a stop with an annular shoulder when the filter cartridge is plugged onto a tube.

[0009] The filter cartridge according to the invention offers numerous advantages. It is easy to handle, as the filter cartridge is simply attached to a pipe or similar component with its smooth edge. Furthermore, it is inexpensive to manufacture, for example, as a deep-drawn part, an injection-molded part, or similar.

[0010] The nose serves as a stop when attaching the filter cartridge to, for example, a pipe, ensuring that the filter cartridge is correctly positioned and, in particular, that the filter material contained in the filter cartridge is not damaged when attaching it.

[0011] Advantageously, the housing is designed to be made of a lightweight, temperature-stable, and chemically inert material, preferably a plastic, e.g., a polyester, in particular a PEEK (polyetheretherketone). In addition to its inert chemical properties, this also ensures sufficient temperature resistance.

[0012] To achieve the necessary filtration performance, the filter material is designed to have several, specifically different, layers that become increasingly fine-pored in the direction of flow. This results in a final layer at the bottom consisting of the finest-pored filter material, while the other layers consist of progressively coarser-pored filter material. Thus, the flow first passes through the coarse-pored layers of the filter material, filtering out coarse particles, and then any remaining fine dust is filtered out in the final, finest-pored layer. This staged arrangement achieves maximum filter storage capacity with minimal pressure loss.

[0013] It has proven advantageous to use a rolled filter fleece as one layer of coarse-pored filter material, with its axis oriented parallel to the flow direction. Such a filter fleece is ideally suited as the first layer in the flow direction. Various plastics are preferably used as the material for the fleece.

[0014] To ensure the filtering out of fine dust, it is further provided that a layer of fine-pored filter material is a microglass fiber filter or a quartz fiber filter, forming the last layer of filter material on the bottom of the housing, particularly in the direction of flow.

[0015] In its design, the axial extent of the two layers of filter materials is further specified as corresponding to the distance between the bottom of the housing and the inwardly projecting nose. Consequently, no further measures are required to secure the filter materials within the housing.

[0016] To optimize filter performance, it can also be provided that, in the direction of flow, the dimensions of the layer of coarse-pored filter material are 10 to 20 times the dimensions of the layer of fine-pored filter material.

[0017] A filter cartridge, as explained above, is ideally suited for a device for determining the amount of dust in the exhaust gas of a solid fuel combustion system, which has a vibrating tube, equipped with a filter device having such a filter cartridge, through which the exhaust gas flows, which is clamped at one end, in which an exciter is connected adjacent to the point of clamping, in which a sensor is provided for determining the frequency of the vibration of the tube and in which an evaluation device calculates an amount of dust captured in the filter cartridge from the deviation from the predetermined resonance and / or a natural frequency of the tube.

[0018] The basic measuring method using such a device is known from DE 10 2007 041 369 A1.

[0019] The filter cartridge according to the invention is explained in more detail with reference to the drawing, which shows only one exemplary embodiment. The drawing shows: Fig. 1: an isometric representation of the cartridge, Fig. 2: a bottom-side, isometric view, Fig. 3: a side view, Fig. 4: a top view, Fig. 5: a view of the ground and Fig. 6: a cut according to line VI, VI in Fig. 3.

[0020] The filter cartridge 1 shown in the drawing has a one-piece, cylindrical housing 2 made of a plastic, preferably a PEEK material. In the flow direction 3 of the filter cartridge, as indicated by the arrow in Fig. 3. Lying at the front, the housing 2 forms a smooth edge 4 for attaching it to a tube or the like.

[0021] Below the rim 4, a circumferential nose 5 is provided, pointing into the interior of the housing 2, which forms a stop with an annular shoulder 6 when it is placed on a tube.

[0022] The base 7 of the housing 2 has a central opening 8 around which a multitude of further, smaller openings 9, 10 are arranged on concentric circles. The openings 8-10 each have circular cross-sections.

[0023] Between the base 7 and an annular shoulder 11 of the nose 5, two layers 12, 13 of different filter materials are arranged. The layer 13 of the filter material arranged on the base 7 is finely porous to filter out fine dust from the exhaust gas flowing through 3 of a combustion appliance. A microglass fiber filter has proven effective for this purpose.

[0024] Layer 12 consists of a coarse-pored filter material, for example a rolled filter fleece, preferably made of a temperature-stable plastic, the axis of which is arranged parallel to the flow direction 3.

[0025] The axial extent in the flow direction of the coarse-pored layer 12 of a filter material is significantly larger than that of the fine-pored layer 13. In the exemplary embodiment, the axial extent of layer 12 in the flow direction 3 is approximately 15 times larger than that of layer 13.

Claims

[1] Filter cartridge, in particular for dust measuring instruments or the like, comprising a housing (2) and with filter material arranged in the housing (2), characterized by , that the one-piece filter housing (2) is designed as a cylindrical slip-on housing with a base (7) provided with perforations (8-10) and a smooth rim (4) opposite the base (7) and that below the rim (4) an inwardly pointing circumferential nose (5) is formed which forms a stop with an annular shoulder (6) when the filter cartridge is slipped onto a pipe. [2] Filter cartridge according to one or more of the preceding claims, characterized by , that the housing (2) is made of a lightweight, temperature-stable and chemically inert material. [3] Filter cartridge according to claim 2, characterized by , that the housing (2) is made of PEEK. [4] Filter cartridge according to one or more of the preceding claims, characterized by, that the filter material has several layers (12,13) ​​which are increasingly finer-pored in the direction of flow (3). [5] Filter cartridge according to claim 4, characterized by , that one layer of coarse-pored filter material (12) is a rolled filter fleece whose axis is arranged parallel to the flow direction (3). [6] Filter cartridge according to claim 5, characterized by , that the filter fleece forms a first layer (12) in the direction of flow (3). [7] Filter cartridge according to one or more of claims 4 to 6, characterized by , that one layer (13) of a fine-pored filter material is a microglass fiber filter or a quartz fiber filter. [8] Filter cartridge according to claim 7, characterized by , that the microglass fiber filter or the quartz fiber filter is arranged on the bottom (7) of the housing (2). [9] Filter cartridge according to any one of claims 4 to 8, characterized by, that the axial extent of the layers (12,13) ​​of the filter materials corresponds to the distance between the bottom (7) of the housing (2) and the inward-pointing nose (5). [10] Device for determining the amount of dust in the exhaust gas of a solid fuel combustion plant, characterized by A tube capable of vibration, equipped with a filter cartridge according to one or more of the preceding claims, through which the exhaust gas flows, and which is clamped at one end, in such a way that an exciter is connected adjacent to the point of clamping, in which a sensor is provided for determining the frequency of the vibration of the tube and in which an evaluation device calculates a quantity of dust captured in the filter device from the deviation from the predetermined resonance and / or a natural frequency of the tube.

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