A drum filter

Abstract

The present application relates to a drum filter comprising a suspension tank for containing a suspension to be filtered, characterized in that the drum filter further comprises a tank head which is sealingly connected to the suspension tank to form a sealed chamber, which is configured for containing a compressed gas having a pressure which can be preset, and which is configured for containing a drum which can be rotated by means of a drum drive, a filter medium which is applied to at least a part of the outer surface of the peripheral surface of the drum, a collection tube which is arranged inside the drum for collecting a filtrate which has passed through the filter medium, and a filter cake discharge tool for separating a filter cake which has been retained by the filter medium and which has built up from the filter medium.

Description

Technical Field

[0001] This application relates to a rotary drum filter for achieving solid-liquid two-phase separation. Background Technology

[0002] Solid-liquid separation equipment is a crucial unit operation device in chemical engineering, primarily used for dehydration, concentration, clarification, purification, and solid particle classification. It is widely used in chemical, petrochemical, light industry, food, pharmaceutical, mining, metallurgy, coal, energy, water resources, and environmental protection fields. The technical level and quality of separation equipment directly affect the possibility of continuous production processes, the advancement of process technology, product quality, energy consumption, and economic and social benefits such as environmental protection.

[0003] A rotary drum filter is an important solid-liquid separation device. It consists of a rotating drum covered with a filter medium. This filter medium traps solid particles in the suspension to be filtered, allowing the liquid phase to pass through, thus achieving solid-liquid separation. This separation yields a filter cake with a low liquid content. A certain pressure difference must be maintained across the filter medium during filtration; this pressure difference is the driving force for filtration. This driving force can be provided by gravity, pressure, or centrifugal force. A rotary drum filter that uses compressed gas to provide the pressure for filtration is called a pressurized rotary drum filter.

[0004] A pressure drum filter typically comprises numerous components, including a drum coated with filter media, a drum drive unit for rotating the drum, a suspension tank for holding the suspension to be filtered, a collection pipe for collecting the filtered filtrate, a device for discharging the filtrate from the collection pipe, and a filter cake discharge tool for separating the filter cake. In the prior art, to accommodate these numerous components and simultaneously provide the filtration driving force, a pressure drum filter typically includes a pressure vessel specifically manufactured from a shell, which may include at least one sealed chamber that can be pressurized by compressed gas. In some prior art solutions, these numerous components are housed as a single unit within the same sealed chamber of the pressure vessel. In other prior art solutions, these components are placed in different sub-chambers within the pressure vessel.

[0005] In these existing technological solutions, pressure vessels are typically manufactured to accommodate numerous components, resulting in a large footprint. This necessitates significant space usage, which becomes unsuitable for space-constrained applications as pressurized drum filters are increasingly used in various industrial settings. Furthermore, it limits the adjustable pressure range within the pressurized drum filter. These traditional pressurized drum filters typically provide a maximum filtration force of 7 Bar; filtration forces exceeding 7 Bar are either difficult to achieve in these traditional pressurized drum filters or lead to a sharp increase in cost. Summary of the Invention

[0006] To address the problems existing in the prior art, this application proposes a rotary drum filter, comprising a suspension tank for containing a suspension to be filtered. The rotary drum filter further comprises a tank cover, which is sealingly connected to the suspension tank to form a sealed chamber. The sealed chamber is configured to contain compressed gas having a preset pressure, and is configured to contain a rotary drum rotatable by means of a rotary drum drive device, a filter medium applied to at least a portion of the outer surface of the drum's circumference, a collection pipe disposed inside the drum for collecting filtrate passing through the filter medium, and a filter cake unloading tool for separating the filter cake formed by the filter medium from the filter medium. Here, the suspension to be filtered is a solid-liquid mixture in which solid particles are dispersed in a liquid. The rotary drum filter proposed in this application is also referred to as a pressurized rotary drum filter.

[0007] In some technical solutions, the drum drive device for driving the drum to rotate and the valve body of the control valve for connecting to the collection pipe to discharge the filtrate are both arranged outside the sealed chamber.

[0008] In some technical solutions, the control valve body and the drum drive device are respectively arranged along the axial direction of the rotation axis of the drum at two opposing end faces of the sealed chamber, particularly at two opposing end faces of the suspension tank. In some technical solutions, the control valve body and the drum drive device are arranged coaxially. In some further technical solutions, the control valve body, the drum drive device, and the drum are all arranged coaxially.

[0009] In some technical solutions, a screw conveyor is also built into the sealed chamber. This screw conveyor continuously transports the filter cake separated by the filter cake unloading tool to a filter cake discharge port located outside the sealed chamber. Here, the filter cake discharge drive device for driving the screw conveyor is located outside the sealed chamber. Alternatively, the screw conveyor can be replaced with other material conveying mechanisms, such as a piston mechanism.

[0010] In some technical solutions, the rotary drum filter further includes one or more stirring mechanisms for stirring the suspension to be filtered in the suspension tank, the stirring mechanisms being arranged inside the sealed chamber. However, the stirring drive device for driving the stirring mechanism is arranged outside the sealed chamber. In some technical solutions, the stirring mechanism can have its stirring frequency adjusted by a frequency converter, which can also be integrated with the stirring drive device and arranged outside the sealed chamber. The stirring mechanism can particularly be configured as a frame-type stirring frame that surrounds a portion of the rotary drum in at least two directions, thereby sufficiently stirring the suspension without affecting the rotation of the drum, resulting in a more uniform mixing of the suspension. In some technical solutions, the axial extension length of the frame-type stirring frame is greater than the axial extension length of the rotary drum together with the filter media thereon. In some technical solutions, the frame-type stirring frame has an arc-shaped stirring surface, the arc-shaped stirring surface being concentrically arranged with the rotary drum.

[0011] In some technical solutions, the stirring drive device is arranged along the radial direction of the drum on one side of the sealed chamber, particularly on one side of the suspension tank.

[0012] In some technical solutions, the stirring drive device and the filter cake discharge drive device are arranged on opposite sides of the sealed chamber, particularly on opposite sides of the suspension tank.

[0013] When the control valve body and the drum drive device are respectively arranged on the two opposite end faces of the sealed chamber along the axial direction of the rotation axis of the drum, and the stirring drive device and the filter cake discharge drive device are arranged on the opposite side of the sealed chamber, a drum filter with excellent balance can be obtained. This helps the drum filter to operate smoothly and thereby reduces operating noise.

[0014] In some technical solutions, the bottom surface of the suspension tank is composed of one or more curved surfaces and / or one or more flat surfaces. In particular, the bottom surface of the suspension tank can include at least one arcuate surface. In some technical solutions, the arcuate surface can be arranged concentrically with the rotating drum. It is also conceivable that the arcuate surface, the rotating drum, and the arcuate stirring surface of the frame-type agitator are arranged concentrically.

[0015] In some technical solutions, the rotary drum filter has a support for supporting it on the ground, the support extending downward beyond the bottom surface of the suspension trough through the axially opposed end faces of the support.

[0016] In some technical solutions, the drum filter further includes a maintenance system for observing its operation and performing maintenance. This maintenance system has an inspection cover constructed in a semi-transparent or fully transparent manner. The inspection cover can be detachably or flipped upside down to the suspension tank. Operators can observe the operation of the drum filter through the inspection cover and, if necessary, remove or flip the inspection cover for maintenance.

[0017] In some technical solutions, the suspension tank and the tank cover are detachably connected to each other, especially by a locking mechanism.

[0018] In some technical solutions, the sealed chamber is isolated from the outside world by a rotary valve and / or a slide gate valve. In particular, in some technical solutions, the sealed chamber is isolated from the outside world by a high-pressure rotary valve.

[0019] In some technical solutions, the control valve body includes multiple functional zones, including at least a filtrate discharge functional zone for discharging filtrate and a gas discharge functional zone for discharging compressed gas. In a further technical solution, the control valve body may also include a filter cake water supply functional zone for supplying water for washing the filter cake and / or a filter cake drying functional zone for supplying drying gas for drying the filter cake.

[0020] In some technical solutions, the filter medium is attached to the outer surface of the circumference of the drum via a porous support plate.

[0021] In some technical solutions, the filter medium is a woven filter cloth, a non-woven filter cloth, or a metal filter medium. For technical solutions involving metal filter media, the metal filter medium can be a sintered metal fiber medium, especially a wedge-shaped cross-section metal wire mesh.

[0022] In some technical solutions, the filter cake unloading tool is a folded belt unloading tool, a back-blowing unloading tool, a scraper unloading tool, a rope unloading tool, a covered filter cloth unloading tool, or a roller unloading tool.

[0023] In technical solutions employing scraper unloading tools, the unloading scraper is arranged in the unloading zone located radially outside the drum and extends particularly in a direction parallel to the axis of the drum. The unloading scraper has a scraping tip for scraping the filter cake formed on the surface of the filter medium, the scraping tip being in close contact with the filter medium or having only a small gap from it. In some technical solutions, the extension direction of the scraping tip of the unloading scraper forms an angle with the radial direction of the drum, thereby making it easier to scrape the filter cake off the outer surface of the filter medium and reducing the load on the unloading scraper.

[0024] In a technical solution employing a cord-type unloading tool, multiple unloading cords are provided. Each of these cords is tensioned and wound around a filter medium applied to the outer circumferential surface of a rotating drum by one or more cord rollers, forming a single closed loop. In a first section of this closed loop, the unloading cord is pressed or adhered to the filter medium, while in a second section, the cord rollers guide the cord away from the surface of the filter medium. The cord rollers are positioned in the unloading zone radially outward of the rotating drum to tension the cords and change their direction, thereby causing the cords to leave the filter medium applied to the drum in the unloading zone. In some solutions, the cord rollers extend in a direction parallel to the axis of the rotating drum. In some solutions, at least one, preferably each, of the unloading cords lies in a plane, and this plane extends, in particular, perpendicular to the axis of the rotating drum. The planes containing the multiple unloading cords extend parallel to each other and are spaced apart by equal intervals. In some technical solutions, 108 such closed loops formed by the unloading ropes can be arranged along the axis of the drum. The rope rollers can be individually configured for each unloading rope, or multiple or even all unloading ropes can share a single rope roller, or a group of rope rollers containing multiple rope rollers. In some technical solutions, two rope rollers shared by all the unloading ropes are arranged in the unloading area of ​​the drum. The position of at least one of these two rope rollers is adjustable, thereby changing the direction of the unloading ropes or the shape of the closed loop formed by the unloading ropes, thus at least adjusting the tension of the unloading ropes. Particularly advantageously, the two rope rollers are configured so that the unloading ropes present an S-shaped form. When the rotary drum filter starts operating, the suspension to be filtered passes through the circumference of the drum and enters a collection pipe, particularly a vacuum tube, located inside the drum. During this process, solid particles in the suspension are trapped on the surface of the filter medium, accumulating to form a filter cake. This filter cake is pressed against the discharge rope in the first section where it is tightly pressed against the filter medium. As the drum rotates to the discharge zone, the discharge rope separates from the surface of the drum, or rather, the filter medium covering the outer circumference of the drum, via rope rollers. This causes the filter cake pressed against the discharge rope to separate from the filter medium covering the outer circumference of the drum, completing the discharge process. The technical solution using a rope discharge tool significantly reduces costs while maintaining at least the same discharge efficiency.

[0025] In some technical solutions, the pressure of the compressed gas supplied to the sealed chamber can be continuously adjusted within the range of 0 bar to 20 bar.

[0026] In some technical solutions, the compressed air is an inert gas or hot steam. Attached Figure Description

[0027] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0028] Figure 1 A first perspective view of a first embodiment of the rotary drum filter proposed in this application is shown;

[0029] Figure 2 A second perspective view of the first embodiment of the rotary drum filter proposed in this application is shown. In order to facilitate the display of its internal structure, the shell structure in the second perspective view is shown in a semi-transparent manner.

[0030] Figure 3 A front view of the first embodiment of the rotary drum filter proposed in this application is shown. To facilitate the display of its internal structure, the first trough end face of the suspension trough in the front view is shown in a transparent manner.

[0031] Figure 4 A right view of the first embodiment of the rotary drum filter proposed in this application is shown;

[0032] Figure 5 A top view of a first embodiment of the rotary drum filter proposed in this application is shown;

[0033] Figure 6 A cross-sectional view of a second embodiment of the rotary drum filter proposed in this application is shown;

[0034] Figure 7 A partial cross-sectional view of a second embodiment of the rotary drum filter proposed in this application is shown.

[0035] In all the accompanying drawings, the same technical features are indicated by the same reference numerals. Detailed Implementation

[0036] Figures 1 to 5 A first embodiment of the rotary drum filter proposed in this application is shown. This rotary drum filter is a pressurized rotary drum filter that provides filtration driving force by loading compressed gas to push the suspension to be filtered through the filter medium, thereby achieving basic separation of the solid and liquid phases in the suspension.

[0037] like Figure 1-4As shown, the sealed chamber of the rotary drum filter proposed in this application is directly formed by the suspension tank 110 and the tank cover 120. The suspension tank 110 is configured not only to contain the suspension to be filtered, but also, in conjunction with the tank cover 120, to house the core components that must operate in a compressed gas environment. This eliminates the need for a dedicated pressure chamber housing in conventional pressurized rotary drum filters to house numerous components, including the suspension tank. This not only reduces the number of components in the rotary drum filter but also shrinks its size and thus reduces the space it occupies. Furthermore, since the sealed chamber formed directly by the suspension tank 110 and the tank cover 120 is smaller than the pressure chamber of a conventional pressurized rotary drum filter, the pressure of the compressed gas loaded within it can reach up to 20 bar. In other words, the compressed air pressure range of the pressurized rotary drum filter provided in this application is between 0 and 20 bar.

[0038] like Figure 1 As shown, the suspension tank 110 includes a first tank end face 111 and a second tank end face 112 facing each other, and a third tank side face 113 and a fourth tank side face 114 facing each other. Furthermore, the suspension tank 110 also has... Figure 1 The bottom surface of the trough, which is not visible in the middle, is 115. Figure 1 In the first embodiment shown, the first feed trough end face 111 and the second feed trough end face 112 are constructed as planes and extend parallel to each other. This simplifies manufacturing and facilitates simple and reliable support of the drum 210 housed within the sealed cavity. However, in other embodiments, it is also possible to consider different configurations depending on the requirements of the application scenario. Figure 1 The first feed trough end face 111 and / or the second feed trough end face 112 shown are configured as outwardly or inwardly arched shapes, or they are configured as two planes extending non-parallel to each other. Figure 1 In the first embodiment shown, the third feed trough side 113 and the fourth feed trough side 114 are also constructed as planes and extend parallel to each other, which simplifies manufacturing and facilitates easy fixation of components that can be disposed outside the sealed chamber. However, it is also possible to construct the third feed trough side and / or the fourth feed trough side as curved surfaces, such as arches, or as non-parallel planes.

[0039] exist Figure 1 In the first embodiment shown, the first end face 111 and the second end face 112 of the suspension tank 110 extend downward beyond the bottom surface 115 of the tank, thereby forming a support for the drum filter, which can be supported on the ground by means of the support.

[0040] Depend on Figure 1As can be seen, a control valve body 410 is arranged at the first material trough end face 111, and the control valve body 410 is arranged coaxially with the drum 210. In this case, the control valve body 410 can be integrally constructed with the drum support device configured to rotatably support the drum 210, thereby simplifying manufacturing and assembly. In some other embodiments, the control valve body can also be arranged offset from the axis of the drum 210, as long as the corresponding fluid connection pipeline can be connected. A compressed gas inlet 321 is also arranged at the first material trough end face 111, through which compressed gas supplied by, for example, a compression pump (not shown) can be introduced into the sealed chamber. In other embodiments, the compressed gas inlet can also be arranged at other material trough end faces or sides of the suspension material trough 110 or at the material trough cover 120.

[0041] A maintenance system and a filter cake discharge system are provided on the side 113 of the third feed trough. The maintenance system includes an inspection cover 1001, which is designed to be semi-transparent to allow the operator to observe the operation inside the sealed chamber. Alternatively, the inspection cover 1001 could be designed to be completely transparent. The inspection cover 1001 is detachably fixed to the side 113 of the third feed trough. When the operator observes an abnormality inside the sealed chamber, or during, for example, regular maintenance periods, the operation of the drum filter can be stopped and the interior of the sealed chamber can be accessed by removing the inspection cover 1001. In other alternative embodiments, Figure 1 The inspection cover 1001 can be flipped and fixed to the side 113 of the third feed trough, and the interior of the sealed chamber can be accessed when necessary by flipping the inspection cover 1001. In other technical solutions, the maintenance system may also include a sight glass, which is mounted on... Figure 1 Inside the inspection cover 1001, the operator can better observe the situation within the sealed chamber by means of the sight glass. The sight glass can be, for example, constructed as a reflector. Alternatively, the sight glass can also consist of a camera and a display screen, wherein the camera is mounted as needed on the inner wall of the suspension tank 110 and / or the tank cover 120, while the display screen is arranged on the inspection cover, for example, on an accessible outer wall of the inspection cover. The filter cake discharge system includes a filter cake discharge port 710, a filter cake discharge drive 720, and a screw conveyor 730 connected to the filter cake discharge drive 720, the filter cake discharge drive 720 being configured to drive the screw conveyor 730 to rotate. In the illustrated first embodiment, the screw conveyor 730 is arranged inside the sealed chamber and therefore... Figure 1 It is not visible in the middle.

[0042] Depend on Figure 1It can also be seen that the trough cover 120 includes a first cover end face 121, a second cover end face 122 arranged opposite to the first cover end face 121, and an arched top surface 123 connecting the first cover end face 121 and the second cover end face 122. Here, the first cover end face 121 and the second cover end face 122 are configured as planes and extend parallel to each other. In other embodiments, it is also possible to use curved surfaces to form the first cover end face and / or the second cover end face, or to arrange the first cover end face and the second cover end face configured as planes in a non-parallel manner. In the illustrated first embodiment, the arched top surface 123 has an arc-shaped cross-section with an angle of less than 180 degrees. In other embodiments, it is also possible to... Figure 1 The arched top surface 123 shown is constructed as two intersecting planes, thus forming a triangular cross-section. In other embodiments, Figure 1 The arched top surface 123 shown can also be constructed as three intersecting planes, thus forming a rectangular cross-section.

[0043] In the first embodiment illustrated, the suspension tank 110 and the tank cover 120 are detachably connected to each other using a threaded connector. In other embodiments, the suspension tank and the tank cover can also be connected by a snap-lock connection, thereby achieving a quick and convenient connection. A seal, such as a sealing strip, is provided at the connection point between the suspension tank 110 and the tank cover 120. The seal can be fixed to the connection edge of the suspension tank 110 and / or the tank cover 120, for example, by adhesive bonding.

[0044] To better illustrate the internal structure of the rotary drum filter... Figure 2 The external housing structure of the rotary drum filter shown is presented in a semi-transparent manner.

[0045] like Figure 2 As shown, the sealed chamber contains a rotating drum 210, a filter medium 310 laid on the outer circumferential surface of the rotating drum 210, a collection pipe arranged inside the rotating drum for collecting the filtered filtrate, and a filter cake unloading tool 610 arranged beside the filter medium 310. In this first embodiment, the filter cake unloading tool 610 is configured as a scraper unloading tool 610', which includes a unloading scraper 611'.

[0046] The drum 210 has a substantially cylindrical shape and therefore a circular cross-section. That is, the drum 210 has two parallel, opposing planes and a circumferential surface connecting the opposing planes. The drum 210 is rotatably supported in the first trough end face 111 and the second trough end face 112 of the suspension trough 110. During operation of the drum filter, the drum 210 is only partially, particularly the lower part, immersed in the suspension to be filtered.

[0047] In the first embodiment illustrated, the filter medium 310 substantially covers the entire outer circumferential surface of the drum 210. However, in some other technical solutions, the filter medium may only be applied to a portion of the outer circumferential surface of the drum. The filter medium can be arranged either continuously or in segments on the outer circumferential surface of the drum. In this first embodiment, the filter medium 310 is in direct contact with the outer circumferential surface of the drum 210 and is connected to each other, for example, by means of adhesion, welding, threading, or locking. However, it is also conceivable to attach the filter medium to the outer circumferential surface of the drum using a porous support plate. That is, the porous support plate is arranged between the filter medium and the outer circumferential surface of the drum, and is connected to both the outer circumferential surface of the drum and the filter medium by means of adhesion, welding, threading, or locking. With the technical solution having a porous support plate, the replacement and maintenance of the filter medium becomes more convenient, while protecting the drum body from damage during filter medium replacement. A particularly advantageous feature is that the porous support plate is detachably connected to the drum. In some technical solutions, the porous support plate can be constructed in a resiliently deformable manner. The filter medium can be made of woven filter cloth, non-woven filter cloth, or metal filter medium. The metal filter medium can be sintered metal fiber medium, especially wedge-shaped cross-section metal wire mesh.

[0048] A collection pipe is arranged inside the drum, extending from the inner circumferential surface of the drum 210 to the control valve body 410. Because compressed gas is loaded in the sealed chamber, and the control valve body 410 is located outside the sealed chamber, this pressure difference causes the suspension to be filtered, contained in the suspension tank 110, to pass through the filter medium 310 and enter the collection pipe located on the inner circumferential surface of the drum 210. At this point, the filter medium 310 traps most of the solid particles in the suspension on its outer surface, while the liquid containing only a small amount or no solid particles, i.e., the filtrate, enters the collection pipe and is discharged through the control valve body 410. As the solid particles trapped on the outer surface of the filter medium 310 accumulate, a filter cake is formed.

[0049] To separate the filter cake from the filter medium 310 for continuous operation of the drum filter, a filter cake discharge tool 610 with a discharge scraper 611' is arranged within the sealed cavity. The discharge scraper 611' is located in the discharge zone on the radially outer side of the drum 210 and extends in a direction parallel to the axis of the drum 310. The discharge scraper 611' has a scraping tip for scraping the filter cake deposited on the surface of the filter medium 310, the scraping tip being in contact with the filter medium 310. The extension direction of the scraping tip of the discharge scraper 611' forms an angle with the radial direction of the drum 210, thereby making it easier to scrape the filter cake off the outer surface of the filter medium 310 and reducing the load on the discharge scraper 611'. In some other embodiments, the scraping tip of the discharge scraper 611' has only a small gap with the filter medium 310, which protects the filter medium 310 from being scratched by the discharge scraper 610'. In these embodiments, at least a portion of the filter cake remaining on the surface of the filter medium 310 can be removed by a regeneration cleaning device also located in the discharge area. Figure 2 As shown, the discharge scraper 611' at least completely covers the filter medium 310 along the axial direction of the drum 210. That is, the extension length of the discharge scraper 611' along the axial direction of the drum 210 is greater than or equal to the extension length of the filter medium 310 along the axial direction. This ensures that the filter cake on the entire outer surface of the filter medium 310 can be scraped.

[0050] A filter cake discharge system is provided below the filter cake unloading tool 610, i.e., the unloading scraper 611' in this first embodiment, so that after the filter cake is scraped off, it can be guided, for example by gravity, through a vertically or nearly vertically arranged channel into the screw conveyor 730 of the filter cake discharge system. The screw conveyor 730 is rotatably supported in a sealed chamber under the drive of the filter cake discharge drive device 720 and discharges the filter cake through the filter cake discharge port 710 by rotation. Here, the screw conveyor 730 is constructed as a screw. The use of the screw conveyor 730 is beneficial for ensuring the continuous operation of the drum filter. However, it is also possible to omit the screw conveyor and use other mechanical structures to discharge the filter cake, although the discharge effect of this technical solution is slightly inferior, but the cost can be reduced.

[0051] Figure 2A stirring mechanism 910 is also shown. The stirring mechanism 910 is optionally arranged within the sealed chamber and is at least partially immersed in the suspension. When the stirring mechanism 910 is driven by the stirring drive device 920, it oscillates, thereby stirring the suspension. The arrangement of the stirring mechanism 910 facilitates uniform mixing of the suspension, thereby improving the filtration effect. In the illustrated first embodiment, the stirring mechanism 910 is configured as a frame-type stirring frame that partially surrounds the rotating drum 210, thereby sufficiently stirring the suspension without affecting the rotation of the rotating drum 210. In the illustrated first embodiment, two frame-type stirring frames are arranged within the sealed chamber, respectively at both ends of the rotating drum 210 and each equipped with its own stirring drive device 920. In an alternative embodiment, only one frame-type stirring frame and one stirring drive device may be arranged, wherein the axial extension length of the only frame-type stirring frame is greater than the axial extension length of the rotating drum 210 together with the filter media 310 thereon. In some embodiments, the frame-type stirring rack has an arc-shaped stirring surface that is concentrically arranged with the rotating drum 210.

[0052] Figure 3 A first embodiment of the rotary drum filter proposed in this application is shown in a front view. To facilitate the display of its internal structure, the first feed tank end face 111 of the suspension feed tank 110 in this front view is shown in a transparent manner.

[0053] Depend on Figure 3 The bottom surface 115 of the suspension tank 110 is visible, and it is composed of two curved surfaces of different curvatures and a flat surface. In alternative embodiments, the bottom surface may also be composed of only a flat surface, only curved surfaces, or one or more curved surfaces and a flat surface in a number different from those shown in this first embodiment. In particular, the bottom surface may be constructed as an arc, which is particularly concentrically arranged with respect to the drum 210. A suspension inlet 510 and a suspension outlet 520 are provided on the bottom surface 115. The suspension inlet 510 opens and extends horizontally toward the second side surface 114 of the suspension tank 110. In some other embodiments, the suspension inlet may also open and extend in other directions, such as obliquely upward. The suspension outlet 520 is located at the lowest point of the bottom surface 115 and opens downward, so that the suspension can be discharged by gravity. In some other embodiments, the suspension discharge port may also be located at other positions on the bottom surface 115 of the trough and extend in other directions, such as extending in a downward direction.

[0054] Depend on Figure 3As can be seen, the stirring drive device 920 is also arranged outside the sealed chamber and connected to the stirring mechanism 910 arranged inside the sealed chamber, thereby driving the stirring mechanism 910 to move, especially to oscillate. In the first embodiment shown, the stirring mechanism 910 is arranged eccentrically relative to the axis of the drum 210.

[0055] Figure 3 Also shown is a control valve body 410, which includes a first outlet 411 and a second outlet 412, a third outlet 413, and a fourth outlet 414 for discharging a gas and filtrate mixture from a collection pipe, each outlet having a different gas-liquid mixing ratio. A backflush port 415 for supplying gas and piping connected to them are also shown.

[0056] also, Figure 3 A rotary valve 810 is also shown, which is arranged between the filter cake discharge port 710 and the screw conveyor 730 to maintain the sealing of the sealed chamber. In some other technical solutions, a gate valve may also be provided additionally or alternatively.

[0057] Figure 4 A first embodiment of a rotary drum filter is shown as viewed from the side 113 of the first trough of the suspension trough 110. The first trough end face 111 and the second trough end face 112 of the suspension trough 110 are visible in this view. Outside the sealed chamber, a control valve body 410 is arranged at the first trough end face 111, and a rotary drum drive device 220 is arranged at the second trough end face 112. Here, the control valve body 410 and the rotary drum drive device 220 are arranged coaxially. Particularly advantageous is that the control valve body 410, the rotary drum drive device 220, and the rotary drum 210 are arranged coaxially. This facilitates simple and reliable support and smooth rotation of the rotary drum 210, and also facilitates reliable cooperation between the control valve body 410 and the rotary drum 210, thereby ensuring smooth fluid introduction and discharge.

[0058] Figure 5 A top view of the rotary drum filter proposed in this application is shown. As can be seen from the top view, a compressed gas inlet 321 is provided at the first end face 111 of the suspension tank 110, while a pressure relief port 322 is provided at the second end face 111 of the suspension tank 110 for reducing the pressure inside the sealed chamber when necessary. The compressed gas pressure inside the sealed chamber can be precisely controlled in a predetermined manner by means of the compressed gas inlet 321, the pressure relief port 322, a compressed gas supply device (not shown), such as a compression pump, and a controller for controlling the compressed gas supply device, to adapt to the filtration requirements of different materials and achieve a better filtration effect. The compressed gas in this application can be air, steam, nitrogen, etc.

[0059] Figure 6 and Figure 7 A second embodiment of the rotary drum filter proposed in this application is shown. The main difference between the second embodiment and the first embodiment lies in the design of the filter cake unloading tool 610; the other parts are the same as the first embodiment and will not be described again here.

[0060] In a second embodiment of the rotary drum filter, the filter cake unloading tool 610 is configured as a "rope unloading tool 610", which includes at least the following components: Figure 6 The unloading line 611”, the first line roller 612”, the second line roller 613”, and as shown Figure 7 The roller support 614” and roller adjustment mechanism 615” are shown. In this second embodiment, multiple discharge ropes 611” are provided, each located in its own plane, which extends perpendicular to the axis of the drum 210. These discharge ropes 611” are tensioned and wound around the filter medium 310 laid on the outer circumferential surface of the drum 210 via a common first rope roller 612” and a common second rope roller 613” to form individual closed loops. Figure 6 As shown, in the first section of each closed loop, the discharge cord 611” is pressed or adhered to the filter medium 310, while in the second section of the closed loop, the discharge cord 611” is guided away from the surface of the filter medium 310 by the first cord roller 612” and the second cord roller 613”. In this second embodiment, the first section occupies approximately 90% of the entire closed loop. The first cord roller 612” and the second cord roller 613” are disposed in the discharge zone on the radially outer side of the drum 210 to tension the discharge cord 611” and change its direction, thereby causing the discharge cord 611” to leave the filter medium 310 laid on the drum 210 in the discharge zone. In this second embodiment, both the first cord roller 612” and the second cord roller 613” extend in a direction parallel to the axis of the drum 210. The first cord roller 612” and the second cord roller 613” are along the axis of the drum 210. The linear direction covers at least the entire filter medium 310. Multiple discharge cords are evenly distributed at equal intervals on the first cord roller 612” and the second cord roller 613”. The first cord roller 612” and the second cord roller 613” are supported on a roller bracket 614”, which is fixed to the suspension tank 110. The first cord roller 612” is fixed to the roller bracket 614” without translation, while the second cord roller 613” is fixed to the roller bracket 614” in a translational manner. Specifically, as... Figure 7As shown, roller adjusting mechanisms 615” are respectively constructed at both ends of the second rope roller 613” along the axis of the drum 310. The roller adjusting mechanisms 615” are fixedly connected to the second rope roller 613” or are integrally manufactured. Correspondingly, elongated through holes are provided in pairs and opposite each other at the roller support 614”. The roller adjusting mechanisms 615” pass through the elongated through holes and are thus movably supported at the roller support 614”. By means of the roller adjusting mechanisms 615”, the position of the second rope roller 613” relative to the drum 210 can be adjusted, thereby changing the tension of the discharge rope 611”. During the operation of the drum filter, the discharge rope 611” may become slack. The tension of the discharge rope 611” can be easily adjusted by the roller adjusting mechanisms 615”, so that the discharge rope 611” is always at a suitable tension to achieve better discharge effect. The first cord roller 612” and the second cord roller 613” cause the discharge cord 611” to have an S-shaped appearance. In particular, the first cord roller 612” and the second cord roller 613” cause the discharge cord 611” to have a directional component opposite to the rotation direction of the drum 210 between the two cord rollers. This ensures that the discharge cord 611” has a sufficiently long contact with the filter medium 310 laid on the surface of the drum 210 with a small space and ensures that the discharge cord 611” is not prone to slippage on the drum 210. In this second embodiment, compared with the second cord roller 613”, the first cord roller 612” is located closer to the upstream position in the rotation direction of the drum 210 and closer to the axis of the drum 210, thereby realizing that the discharge cord 611” has a directional component opposite to the rotation direction of the drum 210 between the two cord rollers.

[0061] When the rotary drum filter starts operating, the suspension to be filtered passes through the circumference of the drum and enters the collection pipe, especially the vacuum tube, arranged inside the drum 210. During this process, solid particles in the suspension are trapped on the surface of the filter medium 310, accumulating to form a filter cake. The filter cake is pressed against the discharge rope 611" in the first section where it is pressed or adhered to the filter medium 310. As the drum 210 rotates to the discharge zone, the discharge rope 611" separates from the surface of the filter medium 310 on the outer circumference of the drum 210, or rather, the drum 210, via the first rope roller 612" and the second rope roller 613". This causes the filter cake pressed against the discharge rope 611" to separate from the filter medium 310 on the outer circumference of the drum 210, completing the discharge process. The technical solution using a rope discharge tool significantly reduces costs while maintaining at least the same discharge effect.

[0062] In some alternative technical solutions, the filter cake unloading tool can also be a folded belt unloading tool, a backflushing unloading tool, a filter cloth coated unloading tool, or a roller unloading tool.

[0063] When the pressurized rotary drum filter proposed in this application is running, compressed gas enters the sealed chamber through the compressed gas inlet 321, forming a predetermined compressed gas pressure as the driving force for filtration. The suspension to be filtered is continuously fed into the suspension tank 110, which forms the sealed chamber, through the suspension inlet 510. Driven by the drum drive device 220, the drum 210 rotates continuously. The filter medium 310, laid on the outer circumferential surface of the drum 210, continuously immerses in and exits the suspension as the drum 210 rotates. Under the pressure of compressed gas, the suspension passes through the filter medium 310, and at least some of the solid particles are trapped on the outer surface of the filter medium 310, accumulating to form a filter cake. The filter cake is scraped off the filter medium 310 by a filter cake discharge tool 610 arranged beside the drum 210 and fed into the screw conveyor 730. Driven by the filter cake discharge drive device 720, the screw conveyor 730 compresses the introduced filter cake by rotation and discharges it through the filter cake discharge port 710. The portion that passes through the filter medium 310 forms filtrate, which is guided through a collection pipe arranged inside the drum 210 to the filtrate outlet 414 of the control valve body 410, and is thus discharged outside the drum filter. High-pressure compressed air is introduced through backflush port 415 to backflush the filter media, removing material adhering to its surface and preventing clogging. Alternatively, clean water / filtrate / alkaline solution can be introduced through port 415 to clean the filter media.

[0064] This application proposes a novel technical concept: utilizing an existing suspension tank for holding the suspension to be filtered and a matching tank cover to form a sealed chamber for containing compressed gas. Specifically, by arranging the drum drive device 220, control valve body 410, filter cake discharge drive device 720, and optionally a stirring drive device 920 all outside the sealed chamber, the volume of the sealed chamber is significantly reduced. Simultaneously, this improves operational convenience, operational flexibility, and ease of maintenance, thereby reducing downtime due to equipment failure. The compressed gas pressure of the pressurized drum filter proposed in this application can be precisely adjusted between 0-20 bar, preferably 0-10 bar, offering a wide adjustment range, short adjustment time, and high adjustment accuracy. This allows it to adapt to the filtration needs of different materials and achieve superior filtration results.

[0065] For example, in starch processing, the solid content is controlled between 10-20%, with starch content exceeding 96.5% and protein content below 0.35%. The entire process uses 100% water as the liquid phase. Direct filtration is performed at a pressure of 3 bar using the pressurized rotary drum filter proposed in this application, without the need for pre-coating, and a washing step is included to improve filtration efficiency. The hourly raw material processing capacity reaches 5.5 cubic meters. After filtration, the filter cake moisture content is 29.4%, and the removal rate of soluble matter in the filter cake reaches over 99.9%, ensuring that the solid content in the filtrate is below 0.3%, thereby guaranteeing the high purity and quality of the starch product.

[0066] For example, in metallurgical processes, the solid phase content is controlled at 10-20%, where the solid phase consists entirely of alloy powder. The liquid phase comprises 94% water and 6% sodium hydroxide. Solid-liquid separation is performed using the pressurized rotary drum filter proposed in this application. This rotary drum filter operates at a pressure of 6 bar, allowing direct filtration without pre-coating, and a washing step is specifically included in the process to improve separation efficiency and product quality. The filter feed throughput is 2.5 cubic meters per hour, demonstrating the filter's high processing capacity. The resulting filter cake has a moisture content of 15.5%, and the removal rate of alkali in the filter cake exceeds 99.9%, ensuring extremely low alkali residue in the filter cake. Simultaneously, the solid content of the filtrate is strictly controlled below 0.05%, guaranteeing the high purity of the filtrate.

[0067] For example, in the fermentation process, the solid phase content is controlled at 10%, consisting of mycelium, proteins, etc. The liquid phase comprises 90% water, 5% alcohol, and 5% inorganic salts. Solid-liquid separation is performed using the pressure rotary drum filter proposed in this application. This filter operates at 8 bar, allowing direct filtration without pre-coating, and includes a washing step to improve separation efficiency and product quality. The filter media used is a five-layer sintered metal mesh with a total thickness of 2 μm. The filter feed throughput is 1.5 cubic meters per hour, demonstrating the filter's high processing capacity. The resulting filter cake has a moisture content of 43.2%, and the removal rate of soluble matter in the filter cake exceeds 99.9%, ensuring extremely low residue levels of soluble matter in the filter cake. Simultaneously, the solid content of the filtrate is strictly controlled below 0.01%, guaranteeing high purity of the filtrate.

[0068] In this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0069] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0070] It should be understood that the above embodiments are for illustrative purposes only and are not intended to limit the invention to the described embodiments. In other words, this application can also be implemented in many other combinations of the features mentioned above, and is not limited to the embodiments shown and described.

Claims

1. A rotary drum filter, the rotary drum filter comprising a suspension tank for containing a suspension to be filtered, characterized in that, The rotary drum filter also includes a feed trough cover, which is sealed to the suspension feed trough to form a sealed chamber. The sealed chamber is configured to contain compressed gas having a preset pressure and is configured to contain a rotary drum that can be rotated by means of a rotary drum drive device, a filter medium laid on at least a portion of the outer surface of the circumference of the rotary drum, a collection pipe arranged inside the rotary drum for collecting filtrate passing through the filter medium, and a filter cake unloading tool for separating the filter cake formed by the filter medium from the filter medium.

2. The rotary drum filter according to claim 1, characterized in that, The drum drive device for driving the drum to rotate and the valve body of the control valve for connecting to the collection pipe to discharge the filtrate are both arranged outside the sealed chamber.

3. The rotary drum filter according to claim 2, characterized in that, The control valve body and the drum drive device are respectively arranged at two opposite end faces of the sealed chamber along the axial direction of the rotation axis of the drum.

4. The rotary drum filter according to any one of claims 1 to 3, characterized in that, The filter cake unloading tool is a rope unloading tool, which includes multiple unloading ropes. Each of the multiple unloading ropes is tensioned and wound around the filter medium laid on the outer peripheral surface of the drum by one or more rope rollers to form a single closed loop. In a first section of the closed loop, the unloading rope is pressed or adhered to the filter medium, while in a second section of the closed loop, the unloading rope is guided away from the surface of the filter medium by the rope rollers.

5. The rotary drum filter according to claim 4, characterized in that, Two rope rollers shared by all the unloading ropes are set in the unloading area of ​​the drum. The position of at least one of the two rope rollers is adjustable, thereby changing the direction of the unloading ropes or the shape of the closed loop formed by the unloading ropes, thus at least adjusting the tension of the unloading ropes.

6. The rotary drum filter according to claim 5, characterized in that, The two rope rollers are configured such that the unloading rope takes on an S-shaped form.

7. The rotary drum filter according to any one of claims 1 to 3, characterized in that, A screw conveyor is also built into the sealed chamber. The screw conveyor is used to continuously transport the filter cake separated by the filter cake unloading tool to the filter cake discharge port arranged outside the sealed chamber. The filter cake discharge drive device for driving the screw conveyor to rotate is arranged outside the sealed chamber.

8. The rotary drum filter according to any one of claims 1 to 3, characterized in that, The rotary drum filter also includes one or more stirring mechanisms for stirring the suspension to be filtered in the suspension tank. The stirring mechanisms are arranged inside the sealed chamber, and the stirring drive device for driving the stirring mechanisms is arranged outside the sealed chamber.

9. The rotary drum filter according to any one of claims 1 to 3, characterized in that, The pressure of the compressed gas supplied to the sealed chamber can be continuously adjusted in the range of 0 bar to 20 bar.

10. The rotary drum filter according to any one of claims 1 to 3, characterized in that, The rotary drum filter also includes a maintenance system for observing operation and maintenance, the maintenance system having an inspection cover constructed in a semi-transparent or fully transparent manner, the inspection cover being able to be fixed to the suspension tank in a detachable or flip-up manner.

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