FILTER ELEMENT FOR SEPARATION OF SOLIDS FROM LIQUIDS AND GASES

Description

[0001] The invention relates to a filter element for separating solids from liquids and gases, comprising two perforated plates arranged parallel to each other and forming a space between the two plates, and enclosed by a filter shell, and to a device for separating solids from liquids and gases comprising at least one filter element.

[0002] Filter elements for separating solid particles from liquids and gases, designed for installation in a pressure vessel in the form of a register to which filter elements are attached, are known. Such filter elements are intended for separating solids, particularly from liquids.

[0003] EP 0 556 188 describes a candle filter in which filter candles with a cylindrical support fabric are grouped together in a register and installed in a pressure vessel. The known candle filter is suitable for separating large quantities of solids; however, with small quantities of solids, the filter elements occupy too large a volume, making the pressure vessel unnecessarily large and expensive.

[0004] EP 2 283 907 A1 describes a device for filtering liquids with a filter element in the form of a cartridge, which is sealed with a plastic film and operated in a support container. Due to the limited size of the filtration area, this type of filtration is used for suspensions with a low solids content.

[0005] CA646598A discloses a filter sheet design and its application in various types of filter devices.

[0006] EP 2 736 619 B1 describes a device for separating solid particles from liquids using flat filter elements arranged in one or more horizontal suspension registers. The filter elements consist of a substantially flat support grid and a completely enclosed filter medium, and spacers are suspended between the filter elements. The spacers ensure that the filter elements are sufficiently far apart to prevent the filter cakes from sticking together after backwashing during cleaning and thus hindering the cleaning process. The spacers require a large volume and large pressure vessels.

[0007] The solutions presented from the prior art allow for the separation of solids from liquids and gases in relatively large pressure vessels. A disadvantage of the prior art is that the filter elements, especially the filter housings, swell during backwashing in cleaning, and there is a risk that the filter cakes adhering to the filter elements will clump together, thus preventing cleaning. To prevent this, large pressure vessels are used, which are space-consuming and expensive. Object of the invention

[0008] The object of the invention is to create filter elements for separating solids from liquids and gases that eliminate the aforementioned disadvantages, namely that the filter shells do not inflate during backwashing to such an extent that their function is impaired, i.e., that the filter cakes are not pressed against each other and stick together, or that the filter elements do not bend. These filter elements have the advantage that they can be arranged close together in a device without the filter cakes adhering to the filter shells touching during filtration. This makes it possible to clean the filter elements by backwashing. Description of the invention

[0009] This problem is solved by a filter element according to the invention. A filter element for separating solids from liquids or gases is disclosed, wherein the filter element comprises a first perforated plate and a second perforated plate, the two perforated plates being arranged parallel to each other and enclosed by a filter shell.The two perforated plates are longitudinally displaceable relative to each other from a fixed to a displaced state and have wedge-shaped spacers on their facing inner surfaces. These spacers each have an inclined side surface, with the inclined side surface of the first plate and the inclined side surface of the second plate facing each other and running parallel to one another, such that the distance between the plates is greater in the displaced state than in the fixed state, and the filter housing is taut in the displaced state. A fastening mechanism is also provided to secure the plates relative to each other in the displaced state.

[0010] The device according to the invention enables the backwashing of the filter elements without the filter housings swelling significantly during backwashing. By shifting the plates relative to each other, the distance between the plates is increased and the filter housing is tensioned, so that no significant bulges form during backwashing that could impair the function of the filter elements.

[0011] The first and second perforated plates of the filter elements have openings across their entire surface, preferably in the form of holes, which allow the filtrate to flow through. The holes are preferably arranged at regular intervals. The plates are made of a hard material, for example, stainless steel or a hard plastic. Preferably, the plates are made of stainless steel. The hard plastic can be, for example, a thermoplastic or thermoset such as vinyl ester resin or epoxy resin. The plastics can also be reinforced with fibers such as glass fibers.

[0012] The first plate preferably has an extension with a hole for receiving a filtrate drain pipe. The extension preferably has two flat plates arranged parallel to each other and spaced apart, the extension being closed on three sides and open on one side, thus forming a cavity. The cavity is connected via the fourth open side of the extension to the space between the first and second perforated plates. The hole in the extension is preferably sealed by a seal, preferably a sealing ring, which seals the two plates of the extension and the filtrate drain pipe from each other. The seal has drainage holes through which the filtrate can flow from the space between the first and second perforated plates, via the extension of the first plate, into the filtrate drain pipe.The filtrate drain pipe also has drainage holes that align with the drainage holes of the seal to allow for unobstructed filtrate drainage.

[0013] The second perforated plate preferably has a stop with a preferably rounded indentation on one transverse side, which is located on the side of the filtrate outlet. The stop can be slid into the open side of the extension of the first plate. In the splayed position of the two plates, the rounded indentation preferably abuts the sealing ring of the first plate and secures it in the desired position. On the transverse side opposite the filtrate outlet and the stop, the second plate preferably has a finishing strip with a bore. The finishing strip serves to seal the two plates in the splayed position, and the bore accommodates a sliding mechanism, for example, a screw, for sliding and locking the two plates into a desired splayed position. The sliding can also be performed manually, for example, using an extension rod.

[0014] The first and second perforated plates preferably have a guide rail on both longitudinal sides, which on the one hand closes the two plates laterally and forms a cavity, and on the other hand serves to guide the plates from an unshifted state to a shifted state and to hold them in position when they are moved relative to each other in the longitudinal direction.

[0015] The filter housing is preferably made of a fabric, nonwoven, felt, or membrane, preferably of plastic or stainless steel. In a preferred embodiment, the filter housing is made of a plastic fabric. During use, the filter element is inserted into the preferably tubular filter housing, and the filter housing is closed at the top and bottom, for example, by welding or with a clamping device. The material of the filter housing is designed to be permeable to liquids and gases, while simultaneously being impermeable to solids. This causes the solids to be retained on the surface of the filter housing during filtration, forming a filter cake, while the liquids or gases flow into the space between the two plates and from there flow off as filtrate via the filtrate drain pipe.When the two perforated plates are in their offset position, the filter sleeve is taut, meaning it fits tightly around them. This has the advantage that the filter sleeve expands less during backwashing than with conventional filter elements and filter sleeves.

[0016] The spacers between the two plates are preferably designed as indentations oriented towards the facing inner surfaces of the plates. The spacers are essentially wedge-shaped. They preferably have a point and an inclined side surface, with the inclined side surface of the first plate and the inclined side surface of the second plate facing each other and running parallel to each other. In a particularly preferred embodiment, the point of the wedge-shaped spacers is flattened.

[0017] Preferably, the wedge-shaped spacer has a teardrop-shaped or rectangular cross-section or plan view, wherein the cross-section is understood to be the cutting plane horizontal to the plane of the plate. In a particularly preferred embodiment, the wedge-shaped spacer has a teardrop-shaped cross-section or plan view. The rectangular spacer preferably has an L-shaped longitudinal section.

[0018] Preferably, the tips of the wedge-shaped spacers of the two perforated plates are offset from each other in the unshifted state, and preferably in contact with each other in the shifted state. When the two perforated plates are shifted longitudinally relative to each other from an unshifted state to a shifted state, the inclined side surfaces of the wedge-shaped spacers slide along each other, thereby increasing the distance between the two plates until the tips of the two spacers are in contact and the maximum distance between the two plates is reached.

[0019] The term "fastening mechanism" refers to a mechanism that, when the two perforated plates of the filter element are in a displaced state, locks into position such that a fixed distance between the two plates is maintained. The fastening mechanism secures the two plates relative to each other in their displaced state.

[0020] Preferably, the fastening mechanism is a screw mechanism arranged on a transverse side of the perforated plates. Preferably, the fastening mechanism is formed by a threaded block and a screw, wherein the threaded block is preferably attached to the first perforated plate via a sheet metal strip, and wherein the screw is guided through a bore in a finishing strip on the transverse side of the second perforated plate opposite a filtrate drain pipe. The screw engages at a specific position such that the two plates are fixed at a desired distance from each other when displaced.

[0021] A further aspect of the present invention relates to a device for separating solids from liquids or gases, comprising a pressure vessel, a filtrate drain pipe, and at least one filter element according to the invention arranged on the filtrate drain pipe. Preferably, the at least one filter element is suspended from the filtrate drain pipe. Preferably, the device comprises several filter elements, wherein the flat filter elements are arranged parallel to one another and connected to each other to form a filter pack, so that a large total filter area per volume is available, which is advantageous for the flow rate and the filter efficiency of the device. In addition, a predetermined free space exists between the individual filter elements over the majority of their vertical longitudinal extent.

[0022] In a further embodiment, the device for separating solids from liquids or gases has an outlet for solid discharge, which is preferably arranged as a discharge nozzle in the lower part of the pressure vessel. This allows for the easy discharge of the separated solid, which collects in the lower part of the vessel by gravity during backwashing of the filter elements through the filtrate drain pipe.

[0023] The device according to the invention can be implemented in various versions, differing primarily in the arrangement of the connections and the closure mechanism. Depending on the application, it is advantageous if the inlets and outlets, also called nozzles, can be arranged in the upper, lateral, or lower region of the pressure vessel. These inlets and outlets on the pressure vessel allow the filling and emptying of the pressure vessel with a suspension, rinsing fluid, or gases, or the drainage of the filtrate. These connections are each sealed in such a way that a sealed zone is located inside the pressure vessel, enabling the creation of overpressure or a vacuum.

[0024] In filtration processes, especially automated filtration processes, it is advantageous to remove the separated solids that have accumulated on the filter elements by backwashing. Backwashing the filter elements can prevent the buildup of a dense layer of solid particles on the filter shell, thus leading to increased filtrate flow. With conventional filter elements and filter shells, the disadvantage is that the filter shell swells during backwashing, causing the filter cakes to touch. This is undesirable. The current solution involves spacing the flat filter elements sufficiently far apart to allow for improved backwashing and removal of the solid particles. This either results in fewer filter elements per pressure vessel and therefore reduced filtration efficiency, or it necessitates larger pressure vessels.The filter elements according to the invention enable backwashing without significant swelling of the filter housings. This allows more filter elements to be used in a pressure vessel and increases filtration efficiency.

[0025] In addition, the present invention comprises an application of a filter element according to the invention in a device for separating solids from liquids or gases.

[0026] Combinations of two or more of the above-listed designs and variants are conceivable and claimed.

[0027] Further advantages of the invention will follow from the description below, in which the invention is explained in more detail with reference to the exemplary embodiments shown in the schematic drawings. Brief description of the characters

[0028] They show: Fig. 1 the first perforated plate in a perspective view of the inside of the plate, Fig. 2 the second perforated plate in a perspective view of the outside of the plate, Fig. 3 the filter element in a perspective view with a partial view of a cross-section through the first and second plates, Fig. 3 a section of the filter element in a perspective view of a cross-section through the first and second plates, Fig. 4 a section of the upper part of the filter element in a perspective view, Fig. 5 a section of the first and second perforated plates in a perspective view, Fig. 6 a section of a perspective view of a cross-section through the first and second perforated plates in the undisplaced state, Fig. 6 a cross-section through the first and second perforated plates in the undisplaced state.Fig. 7A a section of a perspective view of a cross-section through the first and second perforated plate in the displaced state, Fig. 7B a section of the cross-section through the first and second perforated plate in the displaced state, Fig. 8 a section of a perspective view of a cross-section through the first and second perforated plate with fastening mechanism, Fig. 9 a section of a perspective view of a cross-section through another variant of a first and second perforated plate, and Fig. 10 a perspective view of a pressure vessel with filter elements. Exemplary embodiments of the invention

[0029] In the Figure 1The first perforated plate 1 is shown in a perspective view of the inside of the plate 1. The first perforated plate 1 has openings 21 in the form of holes distributed over most of its surface, which allow the flow of the filtrate. The plate 1 is preferably made of stainless steel and has guide rails 17 on both longitudinal sides. The first perforated plate has several spacers 4, which are arranged at regular intervals from one another and each have the same shape. Figure 1The spacers 4 are essentially wedge-shaped and teardrop-shaped with a flattened tip and an inclined side surface. The plate 1 has six spacers 4 per row, and the entire plate has a varying number of rows depending on its length. In this embodiment, the plate has fourteen rows, each with six spacers 4. The first perforated plate 1 additionally has an extension 8 with a hole 12 for receiving a filtrate drain pipe (9, in Figure 10The extension 8 has two flat plates arranged parallel to each other and spaced apart. The extension 8 is closed on three sides and open on one side, thus forming a cavity. The cavity is connected via the fourth open side 20 of the extension to the space between the first and second perforated plates (not shown). The hole 12 is sealed by a sealing ring 14 (in Figure 4 (shown) sealed.

[0030] In the Figure 2 The second perforated plate 2 is shown in a perspective view of the outside of the second plate 2. Like the first plate 1 (in Figure 1(as shown) the second plate 2 has openings 21 in the form of holes distributed over most of its surface, which allow the filtrate to flow through. The plate 2 is preferably made of stainless steel and has guide rails 17' on both longitudinal sides. The second perforated plate 2 has several spacers 4', which are arranged at regular intervals from one another and each have the same shape. Figure 2The spacers 4' are essentially wedge-shaped and teardrop-shaped with a flattened tip and an inclined side surface. The plate 2 has six spacers 4' per row, and the entire plate has a varying number of rows depending on its length. In this embodiment, the plate 2 has fourteen rows with six spacers 4' each. The second perforated plate 2 additionally has a stop 23 with a rounded indentation 24 on one transverse side, which is located on the filtrate outflow side. The stop 23 engages in the open side 20 of the extension 8 of the first plate 1 (in Figure 1 (shown) is movable and the rounded indentation 24 in the displaced state of the two plates on the sealing ring 14 (in Figure 4(as shown) the first plate abuts and is thus fixed. On the transverse side opposite the filtrate outlet and the stop 23, the second plate 2 has a finishing strip 22 with a bore 19. The finishing strip 22 serves to close the two plates in the shifted position, and the bore 19 serves to receive a screw for sliding and locking the two plates in a desired shifted position.

[0031] Figure 3AFigure 1 shows a filter element 5 with a first perforated plate 1 and a second perforated plate 2 in a perspective view from an oblique angle looking down at the outside of the first perforated plate 1, as well as in a partial view A of a cross-section through the first plate 1 and the second plate 2. The spacers 4, one of two guide rails 17, and the extension 8 with the hole 12 and the sealing ring 14 are shown for the first perforated plate 1. The spacers 4', one of two guide rails 17', and the end strip 22 are shown for the second perforated plate 2.

[0032] In the Figure 3B is the subsection A from Figure 3AThe diagram shows a cross-sectional view through the two plates 1 and 2 in their displaced state. The guide rail 17 and spacers 4 of the first plate 1, as well as the guide rail 17', spacers 4', and end strip 22 of the second plate 2, are shown. The spacers 4 and 4' have openings 21 in the form of holes for the flow of the filtrate. The tips of the wedge-shaped spacers 4 and 4' are flattened and are in contact with each other.

[0033] Figure 4Figure 1 shows a section of the upper part of a filter element 5 in a perspective view, including the first plate 1, the second plate, and the filter housing 3. In this view, the first plate 1 is shown with the guide rail 17, the extension 8 with a hole 12, the sealing ring 14, and the drain holes 13. The hole 12 in the extension 8 is sealed by a sealing ring 14, which seals the two plates of the extension 8 and the filtrate drain pipe (not shown) from each other. The sealing ring 14 has drain holes 13 through which the filtrate from the space between the first and second perforated plates 1, 2 can flow via the extension 8 of the first plate into the filtrate drain pipe (not shown). The filtrate drain pipe (not shown) also has drain holes that align with the drain holes of the sealing ring to ensure unobstructed filtrate drainage.In this view, the spacers 4', the openings 21, and the guide rail 17' of the second perforated plate 2 are shown. The filter sleeve 3 is only partially shown. When the filter element 5 is used, the filter sleeve 3 essentially completely encloses both plates 1 and 2. The filter sleeve 3 is tubular and extends over both plates 1 and 2, sealed at the top and bottom (not shown), and also sealed around the sealing ring 14 for the filtrate drain pipe (not shown), so that the filtrate flows only through the filter sleeve into the space between the two plates and from there, via the sealing ring 14 with drain holes 13, into the filtrate drain pipe (not shown).

[0034] Figure 5Figure 1 shows a section of the first plate 1 and the second plate 2 in their position before they are placed on top of each other. The first plate 1 has a guide rail 17, openings 21, and several spacers 4, the spacers 4 having a wedge-shaped, teardrop-shaped form with an inclined side face 10 and a flattened tip 11. The spacers 4' of the second plate 2 are also shown, with the inclined side face 10' and the flattened tip 11'.

[0035] Figure 6A shows a section of a perspective view of a cross-section through the first perforated plate 1 with the spacers 4 with a slanted side surface 10 and the openings 21 and through the second perforated plate 2 with the spacers 4' with a slanted side surface 10'. Figure 6AFigure 1 shows the two plates 1 and 2 in their unshifted state. During assembly, the two plates 1 and 2 are placed on top of each other so that the spacers 4 and 4' on the inside of plates 1 and 2 face each other. The two inclined side surfaces 10 and 10' are parallel to each other. Preferably, they are in contact. The rounded tips preferably rest on the opposite plate, so that, in the unshifted state of the plates, a gap D is formed between the first perforated plate 1 and the second perforated plate 2. The filter sleeve (not shown) is then placed over plates 1 and 2 in this unshifted state, with the fabric not under tension.

[0036] Figure 6B shows a cross-section through the first and second plates 1, 2 in the same arrangement as in Figure 6AThe flattened tip 11 of the spacer 4 of the first plate 1 rests on the second plate 2. The flattened tip 11' of the spacer 4' of the second plate 2 rests on the first plate 1. The inclined side surface 10 of the spacer 4 of the first plate 1 touches the inclined side surface 10' of the spacer 4' of the second plate 2.

[0037] Figure 7A shows a section of a perspective view of a cross-section through the first perforated plate 1 with the spacers 4 with a slanted side surface 10 and the openings 21 and through the second perforated plate 2 with the spacers 4' with a slanted side surface 10'. Figure 7AFigure 1 shows the two plates 1 and 2 in their displaced state. The superimposed plates 1 and 2 are moved into a displaced state either manually or by means of a sliding mechanism, for example a screw, by sliding the inclined side surfaces 10 and 10' along each other until the flattened tips 11 and 11' are aligned and the two plates 1 and 2 are at a distance D' from each other. The distance D' is greater than the distance D between the plates in their undisplaced state, as shown in Figure 2. Figure 6A As described. Due to the increased distance between the two plates, the filter housing (not shown) is taut. Preferably, the circumference of the filter housing is completely filled by the two plates. The fabric of the filter housing is taut in such a way that the filter housing hardly inflates during backwashing, so that the function of the filter elements is not impaired.

[0038] Figure 7Bshows a cross-section through the first and second plates 1, 2 in the same arrangement as in Figure 7A described. The flattened tips 11 of the spacers 4 of the first plate 1 rest on the flattened tips 11' of the spacers 4' of the second plate 2.

[0039] Figure 8 Figure 1 shows a section of a perspective view of a cross-section through the fastening mechanism 6 of the first and second plates 1, 2 in the displaced state. The fastening mechanism 6 is a screw mechanism and is formed by a threaded block 15 and a screw 7. The threaded block 15 is attached to the first perforated plate 1 via a sheet metal strip 16. The screw 16 is inserted through the bore 19 (in Figure 2(shown) is guided in the end strip 22, the end strip being located on the transverse side of the second perforated plate 2 opposite the filtrate outflow. With the filter element in its stationary state, the screw 7 is inserted through the bore into the threaded block 15 and tightened, causing the first plate 1 to shift until the flattened tips of the spacers are aligned and the distance between the two plates is greater than in the stationary state. The filter housing 3 is only partially shown in this illustration.

[0040] Figure 9Figure 1 shows a section of a perspective view of a cross-section through another variant of the first and second perforated plates 1, 2 in their unshifted state. The first plate 1 has spacers 4 with an inclined side surface 10 and a point 11, and the second plate 2 has spacers 4' with an inclined side surface 10' and a point 11'. Both plates also have openings 21. The spacers have a rectangular cross-section and an L-shaped longitudinal section. The point 11, 11' of the spacers 4, 4' is not flattened.

[0041] Figure 10Figure 1 shows a device 25 with a pressure vessel 26, filter elements 5 (shown here without filter housing), an inlet connection 28 through which the liquid or gas to be filtered flows into the pressure vessel 26 (direction of arrow), a filtrate outlet pipe 9 through which the filtrate flows out (direction of arrow), and a discharge nozzle 27 for solids discharge. The device 25 also includes other elements such as a pressure vessel lid with locking screws, a pressure gauge, and feet.

[0042] The filtration process is carried out as follows: the pressure vessel 26 is filled with suspension or gas via the inlet port 28. For this purpose, the atmosphere inside the pressure vessel 26, for example air, is displaced through the filter elements 5 and out of the filtrate outlet pipe 9. The liquid or gas to be filtered flows through the filter sleeves 3 (not shown), which retain the solids, into the space between the two perforated plates, and out of the device 25 via the filtrate outlet pipe 9, where the filtrate, i.e., the filtered liquid or gas, is collected. After filtration is complete, the solids are removed from the filter sleeves 3 (not shown) by backflushing with liquid or backblowing with gas through the filtrate outlet pipe (against the direction of the arrow) and, if necessary, discharged from the pressure vessel 26.For this purpose, either the suspension still located in the pressure vessel 26 is first emptied from the pressure vessel 26 via the discharge nozzle 27 and then backwashed, or the solid is first detached from the filter shells and then emptied together with the remaining suspension via the discharge nozzle 27. Reference symbol list

[0043] 1 First perforated plate 2 Second perforated plate 3 Filter sleeve 4 First plate spacer 4' Second plate spacer 5 Filter element 6 Fastening mechanism 7 Screw 8 Extension 9 Filtrate drain pipe 10 First plate spacer angled side 10' Second plate spacer angled side 11 First plate spacer tip 11' Second plate spacer tip 12 Hole 13 Drain hole 14 Sealing ring 15 Threaded block 16 Sheet metal strip 17 First plate guide rail 17' Second plate guide rail 18 Discharge nozzle 19 Bore 20 Open side 21 Opening 22 End strip 23 Stop 24 Indentation 25 Device 26 Pressure vessel 27 Discharge nozzle 28 Inlet pipe

Claims

1. Filter element (5) for the separation of solids from liquids or gases, wherein the filter element (5) comprises a first perforated plate (1) and a second perforated plate (2), wherein the two perforated plates (1, 2) are arranged parallel to each other and are enclosed by a filter shell (3), characterized in that the two perforated plates (1, 2) can be moved relative to each other in the longitudinal direction from a non-shifted state to a shifted state and the plates (1, 2) have spacers (4, 4') on the inner sides facing each other, which are wedge-shaped and each have a sloping side surface (10, 10'), wherein the sloping side surface (10) of the first plate (1) and the sloping side surface (10') of the second plate (2) are directed towards each other and run parallel to each other, so that the distance (D') between the plates (1, 2) is larger in the shifted state than in the non-shifted state (D) and the filter shell (3) is tensioned in the shifted state of the plates (1, 2), and wherein at least one fastening mechanism (6) is provided which fixes the plates (1, 2) to each other in the shifted state.

2. Filter element (5) according to claim 1, characterized in that the wedge-shaped spacers (4, 4') each have a tip (11, 11').

3. Filter element (5) according to claim 2, characterized in that the tip (11, 11') of the wedge-shaped spacers (4, 4') is flattened.

4. Filter element (5) according to any one of the preceding claims, characterized in that the wedge-shaped spacers (4, 4') have a drop-shaped or rectangular cross-section.

5. A filter element (5) according to any one of claims 2 to 4, characterized in that the tips (11, 11') of the wedge-shaped spacers (4) of the two perforated plates (1, 2) are arranged offset from each other in the non-shifted state, and that the tips (11, 11') of the wedge-shaped spacers (4) of the two perforated plates (1, 2) are in contact with each other in the shifted state.

6. A filter element (5) according to any one of claims 1 to 5, characterized in that the fastening mechanism (6) is formed by a screw mechanism comprising a screw (7) and a threaded block (15) and is arranged on a transverse side of the perforated plates (1, 2).

7. A filter element (5) according to any one of the preceding claims, characterized in that the first perforated plate (1) has an extension (8) with a hole (12) for accommodating a filtrate drain pipe (9).

8. Device (25) for separating solids from liquids or gases comprising a pressure vessel (26), a filtrate drain pipe (9), and at least one filter element (5) arranged on the filtrate drain pipe (9) according to any of the preceding claims.

9. Application of the filter element (5) according to any one of claims 1 to 7 in a device (25) for the separation of solids from liquids or gases.