Van type plate-and-frame filter press and urban water plant sludge dewatering and filter pressing system

Abstract

The utility model relates to a van-type plate-and-frame filter press and an urban water plant sludge dewatering and filter pressing system, the van-type plate-and-frame filter press comprises a filter press body, a plurality of van-type filter plates are sequentially arranged in the filter press body, filter cloth is arranged on the two sides of each van-type filter plate, and the filter cloth is arranged in the filter press body. A filter chamber cavity of the filter press is formed by a gap between every two adjacent compartment type filter plates, the middle of each filter chamber cavity is communicated with a middle hole sludge inlet blow-off channel, filtrate discharge channels are arranged on the two sides of the top and the bottom of each compartment type filter plate respectively, and sludge and air are fed into the filter press body from the middle to the two opposite sides. Filtrate is discharged through the filtrate discharge channels on the two sides of the top and the bottom. Based on the characteristics of urban water plants, the sludge dewatering and filter pressing device is suitable for dewatering and filter pressing treatment on sludge produced by the urban water plants, the relative stability of produced water and sludge yield is kept, and the long-term stability of the filtering performance of the filter cloth can be ensured only by timely cleaning.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sludge dewatering, in particular to a compartment type plate and frame filter press and a sludge dewatering and filter pressing system for municipal water plants. BACKGROUND

[0002] The existing sludge filter pressing and dewatering is commonly carried out by a diaphragm plate and frame filter press. The filter press is composed of a plurality of diaphragm filter plates and compartment type filter plates arranged in cross. The filter chamber and filter cloth installed on the filter plate together form a filter assembly. The sludge dewatering working process of the diaphragm filter press is as follows:

[0003] 1. Preparation stage: start the compression cylinder of the filter press to compress the filter plate assembly by the compression plate to form a whole sealed and pressure-resistant filter chamber, and the filter press has the condition of sludge filter pressing.

[0004] 2. Sludge filling stage: start the sludge pump to input sludge water into the filter chamber and gradually fill it. The clear water is discharged through the filter cloth and the water channel on the filter plate. The sludge is blocked by the filter cloth to form a mud film attached to the filter cloth to participate in subsequent filtration. This process takes about 10 minutes, and the sludge system pressure is about 0.1-0.15 Mpa.

[0005] 3. Low-pressure filtration stage: continue to feed sludge by the sludge pump. The accumulated sludge in the filter chamber is gradually thickened and combined with the filter cloth to form a more effective filter medium. The filtration resistance gradually increases with the sludge feeding, and the sludge system pressure increases accordingly. When the sludge system pressure reaches 0.6-0.7 Mpa, the sludge pump stops. This process takes 1.5-2 hours. At this time, the accumulated sludge in the filter chamber has formed a cake, and the solid content should be above 25%.

[0006] 4. Diaphragm pressing stage: start the pressing pump to input high-pressure water into the diaphragm of the diaphragm filter plate. The diaphragm is expanded under pressure to produce a pressing effect on the sludge cake. The clear water flows out through the filter cloth, and the solid content of the sludge cake is further increased to above 40%. This process takes 0.5-1 hour, and the pressing pressure is about 1.2-1.6 Mpa.

[0007] 5. Air blowing and drying stage: open and close the corresponding valves to input compressed air into the filter chamber. First, the slurry in the sludge feeding channel in the filter plate group is blown back to the sludge pool. Then, the sludge cake is blown to blow out the accumulated water on the surface of the sludge cake and in the water channel of the filter plate to further reduce the water content of the sludge cake. This process takes 5-10 minutes, and the compressed air pressure is about 0.7 Mpa.

[0008] 6. Plate pulling and sludge unloading stage: open the compression cylinder of the filter press to return the compression plate to the open position, and start the plate pulling program. Under the operation of the plate pulling mechanism of the filter press, the filter plates are opened one by one, and the sludge cake falls into the sludge hopper one by one. Thus, a filter pressing and dewatering cycle is completed.

[0009] In the technical scheme of the existing sludge filter pressing and dewatering for municipal water plants, the following technical defects exist:

[0010] 1. The mud production cannot be stable and reach the design value, and with the increase of the number of filter pressing, the mud production is seriously attenuated. In the initial stage of using the filter press, the thickness of the produced mud cake is equivalent to the design value, about 25-30mm, and with the increase of the number of filter pressing, the thickness of the mud cake is gradually thinned, and after about 30 days or 100 times of continuous use, the thickness of the mud cake is thinned to about 15mm, and the mud production is reduced by half. After about 60 days or 200 times of continuous use, the thickness of the mud cake is thinned to about 10mm, and the filter pressing dewatering work is difficult to continue, and the filter cloth must be removed, the drainage channel and the drainage hole of the filter plate are thoroughly cleaned and restored, and even the new filter cloth is replaced, so as to restore the thickness of the mud cake to 25-30mm.

[0011] 2. The auxiliary working time of the filter press is too long, which reduces the effective working time. In order to slow down the speed of the attenuation of the mud production as much as possible, the filter cloth needs to be cleaned once a day, and the filter cloth needs to be disassembled and assembled once every two months, and the filter plate and the filter cloth need to be thoroughly cleaned once.

[0012] 3. The service life of the filter plate and the filter cloth is short. Generally, the service life of the filter cloth is 3-4 months, the service life of the diaphragm filter plate is 2-3 years, and the service life of the matching compartment filter plate is 3-5 years. It is far lower than the service life of the filter plate and the filter cloth of the compartment filter press, and it is also lower than the service life of the diaphragm filter press in other industries. Content of the utility model

[0013] The purpose of the present application is to provide a compartment plate and frame filter press and a sludge dewatering and filter pressing system for urban water plants, which can maintain the stability of dewatering capacity during long-term operation and prolong the service life of the filter plate and the filter cloth.

[0014] In order to achieve the above-mentioned purpose, in a first aspect, the utility model provides a compartment plate and frame filter press, which comprises: a filter press body, a plurality of compartment filter plates are sequentially arranged in the filter press body, filter cloths are arranged on both sides of each compartment filter plate, the gap between adjacent compartment filter plates constitutes a filter chamber cavity of the filter press, a middle hole mud blowing empty channel is communicated in the middle part of the filter chamber cavity, filter liquid discharge channels are arranged on the top and bottom sides of the compartment filter plate, and the filter press body is provided with double-sided mud inlet and air inlet in the middle part, and the filter liquid is discharged through the filter liquid discharge channels on the top and bottom sides.

[0015] In an optional embodiment, the compartment filter plate comprises a head plate, a tail plate and a plurality of intermediate plates arranged between the head plate and the tail plate, a thrust plate and a pressing plate are arranged on the filter press body, the head plate is in pressing abutment with the thrust plate, and the tail plate is in pressing abutment with the pressing plate.

[0016] In a second aspect, the utility model provides a sludge dewatering and filter pressing system for urban water plants, which comprises a blowing empty system, a mud inlet system and the compartment plate and frame filter press of the foregoing embodiment.

[0017] In an optional embodiment, the sludge feeding system comprises a low-pressure sludge feeding system and a high-pressure sludge feeding system, which are arranged in parallel and connected to the chamber plate-and-frame filter press through a common sludge feeding pipeline.

[0018] In an optional embodiment, the sludge feeding system is connected to a sludge conditioning tank through a pipeline, which is used to receive sludge generated in the water production process of a municipal water plant and feed the sludge into the sludge feeding system through a common sludge feeding pipeline.

[0019] The low-pressure sludge feeding system and the high-pressure sludge feeding system can feed sludge into the chamber plate-and-frame filter press through the common sludge feeding pipeline at different stages, respectively.

[0020] In an optional embodiment, the low-pressure sludge feeding system comprises a low-pressure sludge feeding pipeline, a low-pressure sludge feeding pump, and a low-pressure sludge feeding valve group arranged on both sides of the low-pressure sludge feeding pump and connected to the low-pressure sludge feeding pipeline.

[0021] The high-pressure sludge feeding system comprises a high-pressure sludge feeding pipeline, a high-pressure sludge feeding pump, and a high-pressure sludge feeding valve group arranged on both sides of the high-pressure sludge feeding pump and connected to the high-pressure sludge feeding pipeline.

[0022] In an optional embodiment, the low-pressure sludge feeding pump comprises a low-pressure screw sludge feeding pump of a power frequency, and the high-pressure sludge feeding pump comprises a high-pressure screw sludge feeding pump of a variable frequency.

[0023] In an optional embodiment, the air blowing system comprises an air compressor and a process air tank connected in sequence, and the process air tank is connected to the chamber plate-and-frame filter press through a pipeline.

[0024] In an optional embodiment, the chamber plate-and-frame filter press is connected to a filtrate discharge pipeline, and the common sludge feeding pipeline is connected to an air blowing and emptying pipeline.

[0025] In an optional embodiment, the chamber filter plate comprises a polypropylene chamber filter plate, and the filter cloth comprises a polypropylene fiber woven filter cloth.

[0026] In the chamber plate-and-frame filter press, the sludge dewatering process is static pressure filtration, which can keep the filter cloth and the chamber filter plate as basic filter elements stable in performance during long-time operation, thereby ensuring the stability of the sludge dewatering capacity of the filter press.

[0027] The city water plant sludge dewatering pressure filtration system can change pressure according to specific pressure conditions of different stages by low-pressure sludge feeding and high-pressure sludge feeding in different stages, so that the filter cloth and the chamber filter plate are in a static state and a stable stress state during the whole pressure filtration process, and no additional pulling deformation occurs, so that the chamber filter plate and the filter cloth have a relatively long service life.

[0028] The city water plant sludge dewatering pressure filtration system can basically not have the phenomena of crystallization and fouling, is suitable for dewatering and pressure filtration treatment of sludge produced by the city water plant, keeps the relative stability of water production and sludge production, and only needs to be cleaned in time, so that the long-term stability of the filter cloth filtration performance can be ensured.

[0029] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced below, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0031] Figure 1 It is a schematic view of the arrangement structure of the chamber filter plate in the pressure filter body of the present application.

[0032] Figure 2 It is a schematic view of the state of the pressure filter body of the present application in the sludge feeding full stage and the low-pressure filtration stage.

[0033] Figure 3 It is a schematic view of the state of the pressure filter body of the present application in the high-pressure filtration stage.

[0034] Figure 4 It is a schematic view of the state of the pressure filter body of the present application in the blowing and drying stage.

[0035] Figure 5 It is a schematic view of the state of the pressure filter body of the present application in the plate pulling and sludge unloading stage.

[0036] Figure 6 It is a schematic view of the structure of the city water plant sludge dewatering pressure filtration system of the present application.

[0037] Icon:

[0038] 1-chamber plate-and-frame filter press; 11-chamber filter plate; 11a-head plate; 11b-tail plate; 11c-middle plate; 12-filter cloth; 13-filter chamber; 14-middle hole mud feeding and air blowing passage; 15-filtrate discharge passage; 16-thrust plate; 17-pressing plate;

[0039] 2-air blowing system; 21-air compressor; 22-process air tank;

[0040] 3-mud feeding system;

[0041] 31-low pressure mud feeding system; 311-low pressure mud feeding pipeline; 312-low pressure sludge feeding pump; 313-low pressure mud feeding valve group;

[0042] 32-high pressure mud feeding system; 321-high pressure mud feeding pipeline; 322-high pressure sludge feeding pump; 323-high pressure mud feeding valve group;

[0043] 33-shared mud feeding pipeline;

[0044] 34-remote pressure gauge;

[0045] 4-sludge conditioning tank; 41-shared sludge feeding pipeline;

[0046] 5-filtrate discharge pipeline;

[0047] 6-air blowing and emptying pipeline. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0049] In the description of the present application, it should be noted that the positions or location relationships indicated by the terms “inner”, “outer” and the like are based on the positions or location relationships shown in the drawings, or the positions or location relationships in which the products of the present application are usually placed, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms “first”, “second” and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0050] In the description of the present application, it also needs to be explained that, unless otherwise explicitly specified and limited, the terms "set", "connected" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrally connected, it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0051] The chamber type plate and frame filter press and the sludge dewatering filter press system of the city water plant in the present application are mainly used for dewatering and filtering the sludge generated in the water production process of the city water plant.

[0052] Specifically, referring to Figure 1 , and combining Figures 2-5 , the chamber type plate and frame filter press 1 in the present application comprises: a filter press body, a plurality of chamber type filter plates 11 are sequentially arranged inside the filter press body, filter cloths 12 are arranged on both sides of each chamber type filter plate 11, the gaps between adjacent chamber type filter plates 11 constitute filter chamber cavities 13 of the filter press, a middle hole sludge inlet and blow empty channel 14 is communicated in the middle part of the filter chamber cavities 13, slurry discharge channels 15 are arranged on the top and bottom sides of the chamber type filter plates 11 respectively, and the filter press body is provided with double-side sludge inlets and air inlets in the middle part, and the slurry discharge channels 15 on the top and bottom sides are used for discharging the slurry.

[0053] By abandoning the structure of the existing diaphragm filter plate, the dewatering and filtering of the sludge is carried out by the structure of the all chamber type filter plates 11, so that the dewatering and filtering of the sludge can be carried out by the basic principle and form of pressure filtration.

[0054] Based on this, the change of pressure can be selectively carried out according to the specific pressure condition in the later low-pressure and high-pressure filtering stage, so as to keep the filter cloth 12 and the chamber type filter plate 11 stable in the process of pressure filtration.

[0055] By constituting the filter chamber cavities 13 of the filter press through the gaps between adjacent chamber type filter plates 11, combining the middle hole sludge inlet and blow empty channel 14 communicated in the middle part of the filter chamber cavities 13, and the slurry discharge channels 15 arranged on the top and bottom sides of the chamber type filter plates 11 respectively, the double-side sludge inlet condition and the blow empty state in the middle part can be realized, the effective discharge of the slurry is ensured, and the filter cloth 12 can be kept in a relatively stable state.

[0056] From the angle of the composition structure, the chamber type filter plate 11 comprises a head plate 11a, a tail plate 11b and a plurality of intermediate plates 11c arranged between the head plate 11a and the tail plate 11b, the filter press body is provided with a thrust plate 16 and a compression plate 17, the head plate 11a is in compression abutment with the thrust plate 16, and the tail plate 11b is in compression abutment with the compression plate 17, which can facilitate the effective performance of pressure filtration.

[0057] Referring toFigure 6 The utility model focuses on the dewatering pressure filtration of sludge produced in the water production process of city water plant, and based on the compartmental plate-and-frame pressure filter 1 described above, the utility model further provides a sludge dewatering pressure filtration system for city water plant, which comprises a blowing system 2, a sludge feeding system 3 and the compartmental plate-and-frame pressure filter 1 described above.

[0058] The sludge feeding system 3 comprises a low-pressure sludge feeding system 31 and a high-pressure sludge feeding system 32, and the low-pressure sludge feeding system 31 and the high-pressure sludge feeding system 32 are connected with the compartmental plate-and-frame pressure filter 1 in parallel through a shared sludge feeding pipeline 33.

[0059] The sludge feeding system 3 is connected with a sludge conditioning tank 4 through a pipeline, and the sludge conditioning tank 4 is used for receiving sludge produced in the water production process of city water plant and feeding the sludge into the sludge feeding system 3 through a shared sludge feeding pipeline 41.

[0060] Further, the low-pressure sludge feeding system 31 and the high-pressure sludge feeding system 32 can respectively feed sludge into the compartmental plate-and-frame pressure filter 1 through the shared sludge feeding pipeline 41 at different sludge feeding stages and into the compartmental plate-and-frame pressure filter 1.

[0061] In the operation process of the sludge dewatering pressure filtration system in the application, there is no big difference between the low-pressure sludge feeding stage and the existing conventional diaphragm plate-and-frame pressure filter, and the main difference is mainly reflected in the high-pressure sludge feeding stage. Based on abandoning the diaphragm filter plate subjected to pressure deformation and expansion, in the high-pressure sludge feeding stage in the application, the pressure deformation of filter cloth can be reduced under the premise of ensuring normal pressure filtration by changing the sludge feeding pressure according to different sludge feeding pressures.

[0062] From the perspective of the composition of the sludge feeding system 3, the low-pressure sludge feeding system 31 comprises a low-pressure sludge feeding pipeline 311, a low-pressure sludge feeding pump 312 and a low-pressure sludge feeding valve group 313 arranged on the inlet and outlet sides of the low-pressure sludge feeding pump 312 and connected to the low-pressure sludge feeding pipeline 311.

[0063] The high-pressure sludge feeding system 32 comprises a high-pressure sludge feeding pipeline 321, a high-pressure sludge feeding pump 322 and a high-pressure sludge feeding valve group 323 arranged on the inlet and outlet sides of the high-pressure sludge feeding pump 322 and connected to the high-pressure sludge feeding pipeline 321.

[0064] When in the low-pressure sludge feeding stage, the low-pressure sludge feeding pump 312 is opened, and correspondingly the low-pressure sludge feeding valve group 313 is opened, so that the low-pressure sludge feeding pump 312 conveys the sludge in the sludge conditioning tank 4 to the compartmental plate-and-frame pressure filter 1 through the low-pressure sludge feeding pipeline 311 between the shared sludge feeding pipeline 41 and the shared sludge feeding pipeline 33.

[0065] When in the high pressure sludge feeding stage, the low pressure sludge feeding pump 312 is stopped, and the low pressure sludge feeding valve group 313 is closed accordingly; the high pressure sludge feeding pump 322 is started, and the high pressure sludge feeding valve group 323 is opened accordingly, so that the high pressure sludge feeding pump 322 transports the sludge in the sludge conditioning tank 4 to the chamber type plate-and-frame filter press 1 through the high pressure sludge feeding pipeline 321 between the common sludge feeding pipeline 41 and the common sludge feeding pipeline 33.

[0066] In view of the sludge feeding pressure change in the high pressure sludge feeding stage as described above, the low pressure sludge feeding pump 312 comprises a low pressure screw sludge feeding pump with a fixed frequency, and the high pressure sludge feeding pump 322 comprises a high pressure screw sludge feeding pump with a variable frequency, so that the sludge feeding pressure of the high pressure sludge feeding pump 322 can be changed by changing the operating frequency, so that the filter cloth 12 and the plate-and-frame filter plate can maintain a stable state in the dynamic process. It should be noted that, according to the working condition, the low pressure sludge feeding pump 312 can also be selected as a low pressure screw sludge feeding pump with a variable frequency to meet the actual needs in the filter pressing process.

[0067] In view of the existing sludge dewatering process using a diaphragm plate-and-frame filter press, the low pressure filtration and diaphragm pressing are combined in sequence.

[0068] The water source of a city water plant is mostly from rivers, lakes and seas, and the composition ratio of suspended solids is different for different water sources, and the main components are clay, silt, humus soil and algae mud. The particle size of part of the humus soil, algae mud and silt is relatively large, about 10-100 microns, and the particle size of clay is very small, about 0.1-5 microns.

[0069] In the low pressure filtration stage, most of the clay particles can be accumulated with other solid substances in the filter chamber due to the screen filtration of the filter cloth 12, especially the blockage, adsorption and fine sand filtration between the particles of the solid substances in the sludge water. Only a small amount of fine clay can pass through the filter cloth 12 with the clear water in the initial stage. Due to the maximum flow and the highest flow rate of the pump in this stage, little clay is deposited in the water channel of the filter plate, and the resistance in the water channel remains at a low level and will not increase.

[0070] After the pressure filtration is completed, the solid content of the sludge cake in the filter chamber should be more than 25%, and then the sludge cake enters the pressing stage. Generally, the pore size of the filter cloth 12 ranges from 3 to 150 microns, and for this kind of sludge, the filter cloth 12 with a pore size of 10-20 microns has the best filtering effect. Even if the filter cloth 12 with a pore size of 3 microns is selected, the local pore size will be much larger than the rated value under the action of tension, and will reach more than 20 microns.

[0071] The clay smaller than the actual aperture of the filter cloth 12 will enter the filter plate water channel with the clean water during the pressing process, and the water flow during this process is very small. The clay will adhere to the drainage channel of the filter plate. With the increase of the working frequency, the clay adhering to the drainage channel of the filter plate gradually increases, and the corresponding drainage resistance gradually increases, causing the time for the low-pressure filter to reach the rated pressure of 0.6-0.7 Mpa to gradually shorten. The actual amount of mud entering during this stage gradually decreases, and the solid content of the mud cake in the filter chamber gradually decreases. Generally, after about 60 days or 200 times of continuous work, more than 70% of the drainage channels of the filter plate are blocked by clay. After the low-pressure filtration is completed, the solid content of the accumulated mud in the filter chamber can only reach about 15% or even lower. To meet the requirement of the solid content of the mud cake being more than 40%, the mud cake must be compressed to 10-15 mm, that is, the compression stroke of the diaphragm must be increased to 25-30 mm, that is, the diaphragm and the filter cloth 12 on the diaphragm need to be stretched by 25-30 mm, which is more than one time of the design index of 10-15 mm. As a result, the thickness of the mud cake gradually decreases from the normal 25-30 mm to 10 mm, the amount of mud produced is greatly reduced, and the excessive stretching and deformation for many times accelerates the fatigue of the diaphragm and the filter cloth 12, which greatly reduces the service life. Therefore, the existing conventional diaphragm plate frame filter press is not suitable for the dewatering of the sludge of the urban water plant.

[0072] The sludge dewatering and pressure filtration system for the urban water plant in the application specifically combines the chamber type plate frame filter press 1 and the high-low pressure combined sludge feeding. The chamber type plate frame filter press 1 used is a high-pressure chamber type plate frame filter press 1 with a suspended beam structure. The chamber type filter plate 11 is made of reinforced polypropylene. The sludge is fed into the middle hole and the dark current drainage structure is used. The filter cloth 12 is made of single multifilament polypropylene fiber textile filter cloth 12, and the air permeability of the filter cloth 12 is about 10 l / m2s.

[0073] The filter press is composed of a plurality of chamber type filter plates 11 arranged in sequence to form filter chamber cavities 13. The filter chamber cavities 13 and the filter cloth 12 installed on the chamber type filter plate 11 together form a filter assembly.

[0074] The sludge dewatering and pressure filtration system for the urban water plant is configured with one industrial frequency (or variable frequency) low-pressure screw sludge feeding pump and one variable frequency high-pressure screw sludge feeding pump. The lift of the low-pressure sludge feeding pump 312 is 80 m, and the lift of the high-pressure sludge feeding pump 322 is 160 m. The flow of the low-pressure sludge feeding pump 312 is selected according to the allowable filtration speed at the initial stage of pressure filtration and the filtration area of the filter press. The formula is Q=VS, where Q is the flow of the low-pressure pump, V is the filtration speed, and S is the filtration area of the filter press. The filtration speed in the application is in the range of 0.1-0.15 m / h, and the value increases with the increase of the water content of the sludge. For example, the flow of the low-pressure sludge feeding pump of a filter press with a filtration area of 100 m 2 should be 10-15 m 3The flow rate of the high-pressure variable frequency sludge feeding pump is about half of that of the low-pressure sludge feeding pump. The filter area S is a main specification parameter of the filter press, which is determined by multiple factors such as the amount of sludge to be treated, the moisture content of the sludge, the solid content of the sludge cake, the planned operation time, and the number of filter presses.

[0075] In the specific operation process, compared with the prior art, the main improvement point is that in the filtration stage after the low-pressure filtration stage, specifically, after the low-pressure filtration stage of the power frequency low-pressure screw sludge feeding pump is completed, the low-pressure sludge feeding pump 312 is stopped and the variable frequency high-pressure screw sludge feeding pump is started to perform the high-pressure variable filtration stage, as follows:

[0076] Firstly, the starting frequency F1 of the high-pressure sludge feeding pump 322 is 40-45 Hz, and the starting pressure P1 is 0.6-0.7 MPa, i.e. the stoppage pressure of the low-pressure sludge feeding pump 312. When the sludge feeding pressure reaches P2, the frequency of the high-pressure sludge feeding pump 322 is reduced to F2; when the sludge feeding pressure reaches P3, the frequency of the high-pressure sludge feeding pump 322 is reduced to F3; when the sludge feeding pressure reaches P4, the frequency of the high-pressure sludge feeding pump 322 is reduced to F4; when the sludge feeding pressure is greater than P4 for 15 seconds, the pressure maintaining stage is entered, the PLC starts timing, and when the pressure maintaining time arrives, the high-pressure sludge feeding pump 322 is stopped to end the filtration; when the sludge feeding pressure reaches P5 within the pressure maintaining filtration time, the high-pressure sludge feeding pump 322 is stopped to end the filtration regardless of whether the pressure maintaining time has arrived.

[0077] The above-mentioned segmented pressure values P1 to P5 gradually increase from 0.6-0.7 MPa of P1 to 1.15-1.25 MPa of P4 and 1.35-1.45 MPa of P5, and the frequency of the high-pressure sludge feeding pump 322 gradually decreases from 40-45 Hz of F1 to 10-15 Hz of F4, and the pressure maintaining timing time is 10-20 minutes. The whole high-pressure variable filtration stage takes 1.0-1.5 hours, and the solid content of the sludge cake is greater than 45%.

[0078] The remote pressure gauge 34 is arranged on the shared sludge feeding pipeline 33, which can reflect the actual pressure of the sludge feeding pressure P1 to P5 in real time, and provide a basis for the operation of the high-pressure sludge feeding pump 322.

[0079] Similarly, after the high-pressure variable filtration stage is completed, the sludge cake is blown and dried by the blowing system 2, which includes the air compressor 21 and the process air tank 22 connected in sequence, and the process air tank 22 is connected with the chamber type plate and frame filter press 1 through a pipeline.

[0080] The chamber type plate and frame filter press 1 is connected with a filtrate discharge pipeline 5, the filtrate discharge pipeline 5 carries out normal filtrate discharge, and the filtrate is guided out. The common mud inlet pipeline 33 is connected with a blow emptying pipeline 6, the blow emptying pipeline 6 can blow the mud in the mud inlet channel back to a mud pool or a ditch, and can empty the air led to the ditch in the blow drying process.

[0081] The pressure filtration mechanism in the mud inlet full stage, the low pressure filtration stage and the high pressure variable filtration stage in the utility model is that:

[0082] 1. In the mud inlet full stage at the beginning of filtration, the filter cloth 12 is the only filtration medium, and in the case of reasonable filtration speed, the interception precision of the filter cloth 12 is about 5-10 microns, the solid matter and the clear water smaller than the interception precision can pass through the pores of the filter cloth 12, and the solid matter larger than the interception precision is blocked by the filter cloth 12 to form a mud film attached to the filter cloth 12 to participate in subsequent filtration, and the interception precision of the combination of the mud film and the filter cloth 12 is about 2-5 microns.

[0083] 2. In the low pressure filtration stage, the mud concentration in the filter chamber is increased, and gradually thickened into a cake and combined with the mud film and the filter cloth 12 into a more effective filtration medium, and the interception precision is gradually increased with the increase of the mud inlet amount and can reach 0.5 microns.

[0084] 3. In the high pressure variable filtration stage, the solid content rate of the mud cake reaches 25-45%, and the filtration interception capacity is stronger, and the interception precision can reach 0.2 microns.

[0085] 4. In order to obtain the interception precision of each filtration stage, the mud inlet flow and the pressure need to be reasonably matched, the flow and the pressure are too small, the interception precision can be good, but the filtration period is too long, the moisture content of the filter cake is high, and the filtration is not practical, on the contrary, the flow and the pressure are too high, and the interception precision cannot be good.

[0086] As described above, the water source of the city water plant is mostly from rivers, lakes and seas. The composition proportion of the suspended solids is different at different water sources, but the main components are clay, silt, humus soil, algae mud and the like, among which the size of the humus soil, the algae mud and the silt is large, about 5-100 microns, and the particle size of the clay is very small, about 0.1-10 microns, in the mud inlet full stage and the first half of the low pressure filtration stage, the fine clay can pass through the filter cloth 12 with the clear water in the filtration process, because the flow of the pump is the largest and the flow speed is the highest in this stage, the clay is less deposited in the water channel of the filter plate, and most of the clay is discharged with the clear water.

[0087] In the late low-pressure filtration stage and the high-pressure variable filtration stage, with the increase of the concentration of the accumulated sludge in the filter cavity and the formation of the filter cake, the adsorption and blocking of the fine clay are enhanced, and only a small amount of fine clay passes through the filter cloth 12 with the clean water, although the pump capacity and the flow rate are reduced, the carrying effect of the clean water on the clay is reduced, but the flow rate of the clean water is still much larger than the water output during the diaphragm pressing, and after a filtration cycle, the accumulated sludge in the filter plate water channel is very little or even none, which will not cause adverse effects on the next pressure filtration, if continuous operation or the interval of the pressure filtration work cycle is short, the large flow rate in the early stage of the next pressure filtration can also carry away the accumulated sludge in the filter plate water channel.

[0088] Therefore, the sludge dewatering and pressure filtration system of the urban water plant in the utility model will not cause the filter plate water channel to be silted by clay, and will not cause the serious attenuation of the sludge output.

[0089] The filter cloth 12 is in a static state during the entire pressure filtration process, and the stress state is stable without pulling. Moreover, the urban water plant basically will not cause crystallization and scaling, and only needs to be cleaned in time, so that the filtration performance of the filter cloth 12 can be kept stable.

[0090] From the above analysis, it can be seen that the performance of the filter cloth 12 and the filter plate as the basic filtration elements in the application can be kept stable for a long time, so that the stability of the sludge dewatering capacity of the pressure filter is ensured. In addition, during the entire working process, the filter plate and the filter cloth 12 are in a static state without unnecessary pulling and deformation, so that the filter plate and the filter cloth 12 have a relatively long service life.

[0091] With the increase of the number of pressure filtrations, the sludge output of the pressure filtration is kept stable. The thickness of the sludge cake is kept unchanged at the design value of more than 30 mm; the conventional machine washing of the filter cloth 12 is changed from once a day to once every 3 days according to the prior art, and the complete cleaning of the filter plate and the filter cloth 12 is changed from once every 2 months to once every 6-8 months; the service life of the filter cloth 12 reaches 8-12 months, and the service life of the filter plate reaches more than 6 years.

[0092] It should be noted that the features in the embodiments of the application can be combined with each other without conflict.

[0093] The above only describes the preferred embodiments of the application and is not used to limit the application. Those skilled in the art can make various changes and modifications to the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A compartment plate-and-frame filter press, characterized in that include: The filter press body contains multiple chamber filter plates arranged sequentially inside. Each chamber filter plate has filter cloth on both sides. The gap between adjacent chamber filter plates forms the filter chamber of the filter press. The center of the filter chamber is connected to a central hole mud inlet and air blowing channel. The top and bottom sides of each chamber filter plate are respectively provided with filtrate discharge channels. The filter press body receives mud and air from both sides in opposite directions from the center, and discharges filtrate through the filtrate discharge channels on the top and bottom sides.

2. The compartment plate and frame filter press according to claim 1, characterized in that The chamber filter plate includes a head plate, a tail plate, and multiple intermediate plates disposed between the head plate and the tail plate. The filter press body is provided with a thrust plate and a pressing plate. The head plate is pressed against the thrust plate, and the tail plate is pressed against the pressing plate.

3. A municipal water plant sludge dewatering filter press system characterized by, It includes a blow-out system, a sludge feeding system, and the chamber-type plate and frame filter press as described in claim 1 or 2.

4. The municipal water plant sludge dewatering filter press system of claim 3, wherein, The sludge feeding system includes a low-pressure sludge feeding system and a high-pressure sludge feeding system. The low-pressure sludge feeding system and the high-pressure sludge feeding system are connected in parallel and connected to the chamber plate and frame filter press through a common sludge feeding pipe.

5. The municipal water plant sludge dewatering filter press system of claim 4, wherein, The sludge feeding system is connected to a sludge conditioning tank via a pipeline. The sludge conditioning tank is used to receive sludge generated during the water production process of the urban water plant and is fed into the sludge feeding system through a shared sludge supply pipeline. The low-pressure sludge feeding system and the high-pressure sludge feeding system can respectively feed sludge through the common sludge supply pipeline at different stages and pass it into the chamber plate and frame filter press.

6. The municipal water plant sludge dewatering filter press system of claim 5, wherein, The low-pressure sludge feeding system includes a low-pressure sludge feeding pipeline, a low-pressure sludge feeding pump, and a low-pressure sludge feeding valve group installed on both the inlet and outlet sides of the low-pressure sludge feeding pump and connected to the low-pressure sludge feeding pipeline. The high-pressure sludge feeding system includes a high-pressure sludge feeding pipeline, a high-pressure sludge feeding pump, and a high-pressure sludge feeding valve group installed on both the inlet and outlet sides of the high-pressure sludge feeding pump and connected to the high-pressure sludge feeding pipeline.

7. The municipal water plant sludge dewatering filter press system of claim 6, wherein, The low-pressure sludge feed pump includes a low-pressure screw feed pump with a fixed frequency, and the high-pressure sludge feed pump includes a high-pressure screw feed pump with a variable frequency.

8. The municipal water plant sludge dewatering filter press system of claim 3, wherein, The air blowing system includes an air compressor and a process air storage tank connected in sequence. The process air storage tank is connected to the chamber-type plate and frame filter press through a pipeline.

9. The municipal water plant sludge dewatering filter press system of claim 4, wherein, The chamber-type plate and frame filter press is connected to a filtrate discharge pipe, and the common sludge inlet pipe is connected to a blow-out and venting pipe.

10. The municipal water plant sludge dewatering filter press system of claim 4, wherein, The chamber filter plate includes a polypropylene chamber filter plate, and the filter cloth includes a polypropylene fiber woven filter cloth.

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