Sieve bottom assembly for a process vessel for separating liquid phase and solid phase or solid phase suspension

Abstract

Sieve bottom assembly for a process vessel for separating liquid phase and solid phase or solid phase suspension with easy interchangeability of the components crucial for the sieving effect and with minimized clear phase dead volume as well as a discharge path for the solid phase through a generous annular gap that is opened or closed by an inflatable, elastic cuff.

Description

[0001] The invention relates to a sieve plate assembly for a process vessel for separating liquid clear phase and solid phase or solid phase suspension with easy exchangeability of the components crucial for the sieving effect and with minimized clear phase dead volume as well as a discharge path for the solid phase through a generous annular gap that is opened or closed by an inflatable, elastic cuff. Notes on the state of the art:

[0002] In numerous process engineering processes, sieve trays are used at the bottom of process reactors to retain solids or solid suspensions in the vessel, while the solid-free phase (clear phase) is discharged downwards.

[0003] One example is the sieve tray in a chromatography column, which contains adsorbent resin (often called chromatography gel) that reacts with various liquids that are pumped through the column.

[0004] Whether the solid phase or the clear phase contains the valuable material or contains the valuable material depends on the process. The solid phase can be a suspension, meaning solid particles are still mixed with a greater or lesser amount of liquid. In some processes, the solid phase is sieved until completely free of liquid and then dried in a reactor with heat, air or gas flow, and usually also with stirring, until a solid powder or granulate is obtained, e.g., in so-called filter dryers.

[0005] The sieve trays are typically constructed with a fine mesh as the top layer, whose mesh size is tailored to the process, often in the micrometer range. The mesh can be made of metal, plastic, or textile. It can be single-layered or constructed in multiple layers, possibly sintered. Below the mesh, there are typically one or more inserts, often coarser meshes or perforated sheets, which serve to support the mesh and also ensure adequate drainage of the liquid.

[0006] There are processes in which, before sieving, a precisely proportional reaction must take place between a defined amount of solid and a corresponding amount of liquid. One example is the loading of chromatography resin with a protein solution. In this case, there is initially a defined amount of resin suspension, to which a very specific, proportional amount of protein solution is added and is left to react over an extended period of time without the clear phase flowing out. It is undesirable for protein solution to penetrate the sieve without having been in contact with the resin for a sufficiently long time. The clear phase space below the sieve mesh, which is inevitably required by the design, can be referred to as the clear phase dead space because the liquid portion there is not involved in the process. In the example mentioned, the clear phase dead space results in concrete cost disadvantages because the protein solutions are usually only present in small quantities and are particularly expensive.

[0007] Processes in which a more or less viscous solid suspension or even dried solid is present above the screen at the end of the process may have the problem of transporting the suspension out of the reactor. Typically, the reactors have radially branching nozzles above the screen level. Drainage is usually assisted by an agitator in the reactor in the form of a radial discharge. Complete discharge is usually not achievable in this case. In practice, residual discharge is sometimes carried out manually if the solids content is sufficiently high. However, this poses hygienic disadvantages and often also the risk of contact with toxic substances for the personnel.

[0008] Further information on the state of the art in filtering from containers is provided by the following publications: • DE 33 14 937 A1 • US 2010 / 0 307 967 A1 • CN 2 18 451 914 U

[0009] The invention is based on the object of designing a sieve bottom in a process container in such a way that the following advantages are provided or the disadvantages of the conventional embodiments are avoided. • The components crucial for the screening effect should be easily replaceable, allowing the system to be adapted quickly and cost-effectively to changing process requirements. For example, in the case of a metal version, the screen mesh should not necessarily have to be welded to a supporting object. • At the same time, the design of the product-contacting components should meet the requirements of hygienic construction principles, e.g., there should be no internal screws or nuts in contact with the product, and seals should be positioned as flush as possible with the product area. Furthermore, a gradient should always be ensured in the flow direction of the clear phase and solid phase suspension. • The clear phase dead space below the sieve level, which is not involved in the reaction taking place above the sieve level, should be particularly small. • The discharge of the solid phase suspension or the dry solid phase should not take place via a radial, lateral nozzle above the sieve level, but downwards via a generous annular gap, so that the solid phase can be emptied almost residue-free without manual intervention. • The sieve bottom should be suitable for separating the clear phase and solid phase suspension as well as for drying the solid phase if required.

[0010] The object is achieved according to the invention in that the sieve bottom of the process container is constructed from several parts, as in Fig. 1 shown as an example, namely: a) a bottom lower part (1.0) which in the inner area offers an idle-running, i.e. preferably downwardly curved, clear phase collection surface (1.1), in which a preferably flush-sealed bottom seat valve (1.2) with a clear phase outlet nozzle (1.5) is placed at the lowest point for discharging the clear phase of the screening process, and which has a collecting trough (1.3) with a solid phase outlet nozzle (1.4) on the outer circumference, through which the solid phase suspension can be collected and discharged in the corresponding process situation, b) a lower drainage fabric insert (2.0) which rests on the clear phase collection surface (1.1) of the bottom part (1.0), c) a displacement disc (3.0), preferably curved on both sides, which rests on the drainage fabric insert (2.0) and which has vertical holes (3.1) at least on the outer circumference, d) an upper drainage fabric insert (4.0) which rests on the displacement disc (3.0) or is embedded in it, e) a sieve mesh (5.0), the mesh size of which is selected according to the process requirements so that the solid phase components in the suspension are separated from the clear phase, f) a sieve clamping ring (6.0) which is screwed tightly to the bottom part (1.0) and thereby tensions the sieve mesh (5.0) downwards with an annular collar (6.1) and thereby clamps it against the displacer disc (3.0) and the edge area of ​​the clear phase collection area (1.1), wherein preferably the contours of the annular collar (6.1) and the displacer disc (3.0) are matched to one another in such a way that when tensioning down, i.e. screwing the sieve clamping ring (6.0) to the bottom part (1.0), the sieve mesh (5.0) is flanged downwards on the outer circumference so that the upper side of the annular collar (6.1) is at the same level as or lower than the upper side of the sieve mesh (5.0) in order to achieve idle flow, g) a sealing surface (6.2) on the outer circumference of the strainer clamping ring (6.0), h) an annular, elastic sealing sleeve (7.0), which is pressed against the sealing surface (6.2) on the screen clamping ring (6.0) by means of gas or liquid pressure, or is retracted from it again, depending on the process situation, whereby the sealing sleeve (7.0) is held by a sealing sleeve support ring (8.0) by means of a form-fitting contour, via which the gas or liquid is supplied or discharged via the bore (8.1) to tension the sealing sleeve, i) a series of openings (6.3) on the circumference of the screen clamping ring (6.0) below the sealing surface (6.2), through which, when the sealing sleeve (7.0) is open, the solid suspension can flow from the process chamber above the screen mesh (5.0) to the collecting channel (1.3) in the bottom part (1.0), j) a counter flange (9.0) on the process vessel to which the sieve plate assembly is screwed and sealed.

[0011] The parts are clamped together by screws and sealed against each other and the environment by O-rings in the O-ring grooves (10.1, 10.2, 10.3). The bottom seat valve (1.2) is also sealed into the bottom section (1.0) with an O-ring.

[0012] The sieve clamping ring (6.0) is also sealed against the bottom part (1.0) by means of an O-ring (10.4).

[0013] The displacer disc (3.0) as well as the lower drainage fabric insert (2.0) and the upper drainage fabric insert (4.0) are loosely inserted components that do not require welding or screwing, but rather are simply clamped. If process requirements change, they can be easily replaced and replaced with modified designs. For example, the drainage fabric inserts can be made with a coarser mesh and thicker wires if the displacer disc (3.0) is made thinner by the corresponding amount.

[0014] Likewise, the mesh (5.0) is loosely inserted, sealed, and clamped by an O-ring (10.5), so it can easily be replaced with a mesh with different properties if requirements change. If flexibility is not required, the mesh (5.0), if made of metal, can alternatively be welded to the mesh clamping ring (6.0) at the outer perimeter.

[0015] The process flow can, for example, take place as simplified below: 1. The reactor is partially filled with a resin while the sealing collar (7.0) is closed. 2. A liquid intended to react with or wash the resin is added and stirred. The thin interstices above and below the displacer disc (3.0), i.e., the remaining spaces between the webs (wires) of the upper drainage fabric insert (4.0) and lower drainage fabric insert (2.0), result in only a very small clear phase dead space. 3. After the appropriate exposure time, the clear phase is drained through the now opened bottom seat valve (1.2). Due to the curvature of the displacer disc (3.0), the clear phase flows radially outward in the space between the upper drainage fabric insert (4.0) and reaches the vertical holes (3.1) on the outer circumference of the displacer disc (3.0). Alternatively, the displacer disc (3.0) can also be provided with vertical holes distributed across its entire surface. This would promote the drainage of the clear phase but increase the clear phase dead volume. 4. In the space between the lower drainage fabric insert (2.0), the clear phase flows inwards due to the downwardly curved clear phase collection surface (1.1) and reaches the bottom seat valve (1.2). 5. After the clear phase has been removed, steps 2 to 4 are repeated several times if necessary. 6. At the end of the process, the solid suspension located above the sieve mesh (5.0) is emptied. To do this, the pressure is sucked out or released from the sealing sleeve (7.0), causing it to bulge back and open an annular gap (7.1) for emptying. The solid suspension empties into the collecting trough (1.3) and flows out via the solid phase outlet nozzle (1.4). Typically, a suitable fluid is used for subsequent washing. The collecting trough is preferably designed with a significant gradient towards the solid phase outlet nozzle (1.4), ie in this case according to Fig. 1 milled.

[0016] If the aim of the process in question is to remove the solid phase in a dried state, the above-described alternative design of the displacer disc (3.0) with vertical holes (3.2) distributed across the entire surface is advantageous, as these allow gas, or possibly heated gas, introduced from below via the bottom seat valve (1.2) to be more evenly distributed throughout the solid layer. The drying process can be supported by stirring the solid layer.

[0017] Furthermore, in the case of a dry solid phase, it is alternatively provided that the collecting trough (1.3) is designed with a particularly steep gradient towards the solid phase outlet nozzle (1.4), so that the discharge of dried solid can also be carried out in a favorable manner using gravity.

[0018] One embodiment of this can be designed by making the collecting trough (1.3) in the lower base section (1.0) open at the bottom, i.e. without a base surface. An annular space consisting of two concentric cylinders that are cut off at an angle at the bottom on the same plane, e.g. at a 45° angle, is welded or flanged to the lower base section (1.0) from below. The resulting inclined, elliptical ring plane is closed from below with an annular, elliptical base attached to the incline. An outlet nozzle is attached at the lowest point of the inclined base, i.e. at the pointed end. The steepness of the base thus created significantly promotes the sliding of powder or granules towards the outlet. During discharge, it is preferably provided to provide support with a gas flow from the reactor chamber, either by applying overpressure to the reactor chamber or by applying negative pressure to the suction side, or both.

[0019] Furthermore, a gas flow or intermittent gas addition can take place via the clear phase valve and the sieve bottom, so that residual quantities are whirled up on the sieve surface and thus fed into the suction in the direction of the annular gap.

Claims

[1] Sieve bottom assembly for a process vessel for separating liquid phase and solid phase or solid phase suspension, characterized by that the bottom of the process vessel is made up of several parts, namely: a) a bottom lower part (1.0) which, in the inner area, offers an idle-running, i.e. preferably downwardly curved, clear phase collecting surface (1.1), in which a preferably flush-sealing bottom seat valve (1.2) is placed at the lowest point for discharging the clear phase of the screening process, and which has a collecting trough (1.3) on the outer circumference, through which the solid phase suspension can be collected and discharged in the corresponding process situation, b) a lower drainage fabric insert (2.0) which rests on the clear phase collection surface (1.1) of the bottom part (1.0), c) a displacement disc (3.0), preferably curved on both sides, which rests on the drainage fabric insert (2.0) and which has vertical holes (3.1) at least on the outer circumference, d) an upper drainage fabric insert (4.0) which rests on the displacement disc (3.0) or is embedded in it, e) a sieve mesh (5.0), the mesh size of which is selected according to the process requirements so that the solid phase components in the suspension are separated from the clear phase, wherein an O-ring (10.5) or a flat seal is preferably provided in the clamping area on the outer circumference, f) a sieve clamping ring (6.0) which is screwed tightly to the bottom part (1.0) and thereby tensions the sieve mesh (5.0) downwards with an annular collar (6.1) and thereby clamps it against the displacer disc (3.0) and the edge area of ​​the clear phase collection area (1.1), wherein preferably the contours of the annular collar (6.1) and the displacer disc (3.0) are matched to one another in such a way that when tensioning down, i.e. screwing the sieve clamping ring (6.0) to the bottom part (1.0), the sieve mesh (5.0) is flanged downwards on the outer circumference so that the upper side of the annular collar (6.1) is at the same level as or lower than the upper side of the sieve mesh (5.0) in order to achieve idle flow, g) a sealing surface (6.2) on the outer circumference of the strainer clamping ring (6.0), h) an annular, elastic sealing sleeve (7.0), which, depending on the process situation, is pressed against the sealing surface (6.2) on the screen clamping ring (6.0) by means of gas or liquid pressure or is retracted from it again, whereby the sealing sleeve (7.0) is held by a sealing sleeve support ring (8.0) by means of a form-fitting contour, via which the gas or liquid is supplied or discharged to tension the sealing sleeve, i) a series of openings (6.3) on the circumference of the screen clamping ring (6.0) below the sealing surface (6.2), through which, when the sealing sleeve (7.0) is open, the solid suspension can flow from the process chamber above the screen mesh (5.0) to the collecting channel (1.3) in the bottom part (1.0), j) a counter flange (9.0) on the process vessel to which the sieve plate assembly is screwed and sealed. [2] Sieve bottom assembly for a process vessel for separating liquid phase and solid phase or solid phase suspension according to claim 1, characterized by that the displacement disc (3.0) is provided with holes (3.2) or millings distributed over the entire surface. [3] Sieve bottom assembly for a process vessel for separating liquid phase and solid phase or solid phase suspension according to claim 1, characterized bythat the collecting trough (1.3) is designed with a particularly steep gradient in the direction of the solid phase outlet nozzle (1.4), in that the annular collecting space for the solid phase in the lower part of the base (1.0) is designed to be open at the bottom, and in that an annular space is welded or flanged to the lower part of the base (1.0) from below, which annular space consists of two concentric cylinders which are cut off at an angle at the bottom on the same level, wherein the resulting inclined, elliptical annular plane is closed from below with an annular, elliptical base attached to the slope, wherein an outlet nozzle is attached to the lowest point of the inclined base. [4] Sieve bottom assembly for a process vessel for separating liquid phase and solid phase or solid phase suspension according to claim 1, characterized bythat instead of or in addition to the lower drainage fabric insert (2.0) or upper drainage fabric insert (4.0), contours, e.g. in the form of milled channels, are also incorporated into the clear phase collection surface (1.1) or into the displacer disc (3.0).

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