CN113262550A

CN113262550A - Press cover for filter

Info

Publication number: CN113262550A
Application number: CN202110389574.2A
Authority: CN
Inventors: 陈崔龙; 张德友; 周进; 邓超; 张曼曼; 方毅; 吕彤
Original assignee: HEFEI GENERAL ENVIRONMENT CONTROL TECHNOLOGY CO LTD; Hefei General Machinery Research Institute Co Ltd
Current assignee: HEFEI GENERAL ENVIRONMENT CONTROL TECHNOLOGY CO LTD; Hefei General Machinery Research Institute Co Ltd
Priority date: 2021-04-12
Filing date: 2021-04-12
Publication date: 2021-08-17
Anticipated expiration: 2041-04-12
Also published as: CN113262550B

Abstract

The invention relates to the technical field of solid-liquid separation, in particular to a gland for a filter, which is applied to a filter cylinder of a conventional filter. The invention comprises a piston cover which is arranged in a filter cylinder of the filter and used for dividing the filter cylinder of the filter into an upper cavity and a lower cavity, and a main shaft which is used for driving the piston cover to generate axial reciprocating motion; the bottom surface of the piston cover is provided with a filter pressing surface for filter pressing materials, and the outer edge of the piston cover is coaxially provided with an annular expansion bag which can be inflated or filled with liquid so as to generate radial expansion and contraction actions. The invention has the advantages of convenient processing, simple operation and maintenance and compact and reasonable structure, can be installed on the traditional vertical filter, solves the problem that the traditional vertical filter cannot have reaction crystallization, can realize the purpose of filtering materials by utilizing the hydraulic pressure extrusion effect, and is particularly suitable for compressible materials.

Description

Press cover for filter

Technical Field

The invention relates to the technical field of solid-liquid separation, in particular to a gland for a filter, which is applied to a filter cylinder of a conventional filter.

Background

With the development of technology and production requirements, the functional integration of the device is higher and higher. In the field of filtering equipment, a three-in-one type filter appears, integrates three functions of filtering, washing and drying into one machine, shortens the process transfer, improves the production efficiency, reduces the labor intensity, has good adaptability to various materials, is particularly suitable for treating slurry which is difficult to filter and combustible, explosive, toxic, volatile, easily-polluted and other materials, is ideal equipment for solid-liquid separation in industrial departments such as medicines, pesticides, foods, chemical industry, dyes and the like, and has wide application. The three-in-one filter is a vertical tank container, which mainly comprises a transmission part, a lifting part, a paddle mechanism, a filter disc and other main parts, wherein the paddle mechanism can be lifted and rotated forwards and backwards, can carry out pulping and washing on filter cakes, can accelerate the washing process, reduce the consumption of washing liquid and has better washing effect; the three-in-one filter adopts a pressurizing and filtering mode, and is pressurized by taking compressed gas such as air or nitrogen and the like as a pressure source, so that pressure difference is formed at two sides of a filter disc, moisture in materials is removed, a filter cake is intercepted, and the materials are automatically removed by blades after being dried. The working mode is just the same, so that the three-in-one filter has the following problems during filter pressing and dehydration: first, a large amount of compressed gas is required, making the operating cost high. Secondly, once the materials contain volatile organic compounds or toxic and harmful substances, the organic compounds or the toxic and harmful substances can also volatilize into the compressed gas, and then a large amount of waste gas is generated. It is common practice in the industry to subject the exhausted waste gas to additional treatment such as recycling or incineration, which obviously increases the operating cost. Thirdly, the bottom of the three-in-one filter is provided with a filter screen, the bottom of the filter screen is a mother liquor collecting cavity, and the structure can not meet the requirement of reaction crystallization in the same container. Because reaction liquid gets into jar body after, can get into filter screen and mother liquor and collect the chamber, goes on along with reaction time, and the crystal is appeared, can block up the filter screen, and the mother liquor is collected the crystal and also can be followed the mother liquor and flowed away in the chamber, not only need frequently carry out online maintenance to the filter screen, wastes time and energy, also can cause the extravagant phenomenon of raw materials, the urgent need be solved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides the gland for the filter, which has the advantages of reasonable structure and high cost performance, is convenient to process, simple to operate and maintain, compact and reasonable in structure, can be installed on the traditional vertical filter, can realize the purpose of filtering materials by utilizing hydraulic pressure extrusion while solving the problem that the traditional vertical filter cannot have reaction crystallization, and is particularly suitable for compressible materials.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a gland for filter which characterized in that: the device comprises a piston cover and a main shaft, wherein the piston cover is arranged in a filter cylinder of the filter and used for dividing the filter cylinder of the filter into an upper cavity and a lower cavity; the bottom surface of the piston cover is provided with a filter pressing surface for filter pressing materials, and the outer edge of the piston cover is coaxially provided with an annular expansion bag which can be inflated or filled with liquid so as to generate radial expansion and contraction actions.

Preferably, the piston cover is coaxially and penetratingly provided with a connecting seat for connecting the spindle; the connecting seat is in a cylindrical shape with an upward barrel opening, and the bottom end of the main shaft is coaxially inserted into the barrel cavity of the connecting seat and forms rotation stopping fit with the barrel cavity; the main shaft is a hollow shaft body, the expansion bag is an air bag which is coaxially arranged at the outer edge of the piston cover, and air radially penetrates through the connecting seat and enters a bag cavity of the expansion bag through an air passage preset in the piston cover after entering through an inner cavity of the main shaft.

Preferably, the cross section of the expansion bag is in a U-shaped groove shape with an opening facing to the direction of the piston cover, and two groove walls of the expansion bag are respectively fixed at the piston cover through a group of compression rings in a pressing mode.

Preferably, the piston cover is in a barrel shape with a downward barrel opening, the air passage extends along the barrel bottom of the piston cover in the radial direction, then extends along the barrel wall of the piston cover in the axial direction and is communicated to the outer ring cavity; the outer ring cavity is provided with an air hole used for communicating the cavity of the expansion capsule.

Preferably, the upper pore plate is covered at the barrel opening of the piston cover, so that the upper pore plate and the barrel cavity of the piston cover are enclosed together to form a liquid accumulation cavity for temporarily retaining the filtrate; filtrate enters the dropsy cavity through the sieve pores of the upper pore plate and then enters the central tube of the main shaft through the radial holes until the filtrate is discharged out of the filter cylinder of the filter; the central tube and the main shaft tube cavity are coaxial with each other, and an annular cavity channel formed by enclosing the outer wall of the central tube and the wall of the main shaft tube cavity forms an air inlet cavity.

Preferably, an upper filter screen is attached to the bottom plate surface of the upper orifice plate; the filtering holes at the upper filtering net are communicated with the sieve pores at the upper pore plate, and the aperture of the filtering holes is smaller than that of the sieve pores.

Preferably, the lower plate surface of the upper orifice plate is axially and convexly provided with a stirring paddle for playing a stirring function; the stirring paddle is S-shaped; the top surface of the piston cover is also provided with an attached paddle.

Preferably, in the axial direction of the main shaft, a fit clearance for filtrate to pass through is reserved between the upper orifice plate and the connecting seat.

Preferably, the liquid accumulation cavity is internally provided with radial support ribs, and the top surface of the piston cover is also provided with radial reinforcing ribs.

Preferably, an axial gap is reserved between the main shaft and the bottom surface of the barrel of the connecting seat, the axial gap forms a liquid collecting cavity, and the radial hole is communicated with the liquid accumulating cavity and the liquid collecting cavity.

The invention has the beneficial effects that:

1) through the scheme, the invention provides the gland which can generate reciprocating linear motion at least along the axial direction of the vertical filter, and the vertical container, namely the filter cartridge of the filter can be sealed and isolated by the inflation sealing operation of the expansion bag on the outer circumferential surface, namely the outer edge of the gland, so that an upper cavity and a lower cavity are formed. When the device works, the lower cavity is positioned below, and the upper cavity can be independently used for carrying out reaction crystallization from the outside of the lower cavity due to the sealing effect of the expansion capsule on the passing clearance, and the reaction process can be carried out with temperature control and stirring according to the process requirements. After the reaction crystallization is finished, the inflatable seal of the expansion bag is released, at the moment, the upper cavity and the lower cavity are communicated through the reopened passing gap, and even the whole device can be lifted to a high position, so that the mixed liquid after the reaction crystallization enters the lower cavity. The inflation bag inflates once more, and whole piston lid from top to bottom moves under hydraulic pressure force effect, extrudees the mixed liquid, realizes the liquid filtering function through the filter screen of traditional vertical filter self-carrying promptly to form the filter cake. Even if necessary, the main shaft can be designed to have a rotation function, when the washing is needed, the piston cover rises again, the expansion bag discharges air or liquid, so that the passing gap is opened, the washing liquid is sprayed into the whole cylinder cavity, the piston cover rotates and descends, the mixing and stirring are carried out, the washing liquid and the filter cake are fully mixed, the slurrying washing is formed, and the purposes of reducing the washing time and reducing the consumption of the washing liquid are achieved. The final washing liquid and filtrate can be discharged along the liquid outlet of the vertical filter, and the filter cake can be discharged along the discharge hole of the vertical filter, thus finally completing the filtering purpose.

Obviously, the invention can be directly applied to the traditional vertical filter, can completely replace the traditional air pressure filtering structure, and synchronously has the advantages of convenient processing, simple operation and maintenance and compact structure. Practice proves that the maximum diameter of the filter cartridge of the applicable filter can reach more than 3500mm, the filtering area is more than 9 square meters, and the effective volume is 10m³Above, can satisfy the large-scale production needs. The hydraulic pressure extrusion filtering does not generate waste gas, is particularly suitable for compressible materials, synchronously solves the problem that a vertical filter cannot have reaction crystallization at the same time, and has obvious effect. Even if necessary, the invention can be applied to other existing filter structures such as a horizontal filter and the like, and has no need of horizontally arranging the main shaft or performing adaptive conversion of other installation stations, so that the invention has extremely wide application range.

2) In the invention, the expansion bag is a core part; in actual design, the expansion bag can realize the expansion function by pumping and injecting liquid, and can also realize the controllable contraction and expansion effects of the expansion bag in a gas pumping and injecting mode. During specific design, gas enters the expansion bag through the main shaft tube cavity and the air passage; more specifically, the gas can enter the air passage through an air inlet cavity formed by the main shaft pipe cavity wall and the central pipe in sequence, and finally flows into the expansion bag cavity through the air hole at the outer ring cavity, so that the online inflation and deflation functions of the expansion bag are ensured on the premise that the piston cover can generate axial reciprocating motion, and the compactness and the working reliability of the structure can be effectively ensured.

3) The expansion bag can be an independent annular tubular bag body, or a groove-shaped bag is adopted, so that the aim of positioning relative to the piston cover is fulfilled by utilizing the pressing function of the upper and lower groups of pressing rings, the gas inlet and outlet effects are realized by the dead alignment of the notch of the expansion bag and the gas hole, and the operation is extremely reliable and stable.

4) The arrangement of the upper filter screen aims to lay a foundation for secondary extraction of filtrate at the material position while the piston cover has an original axial pressure application function. In other words, the piston cover can be simply used as a piston structure to physically separate the upper cavity from the lower cavity and directly apply pressure to the material at the lower cavity, so that the purpose of filtering and separating filter cakes and filtrate is achieved; or as described in the invention, the filtrate in the lower cavity can be naturally discharged through the filter screen at the vertical filter, no matter the filter screen at the side wall or the filter screen at the bottom, and when the filtrate in the material under natural gravity can not normally drop or only slightly drops, the downward pressure of the piston cover is applied, so that the filtrate respectively passes through the original filter screen at the lower cavity and the upper filter screen at the piston cover, the purpose of completely discharging the filtrate in the material is realized, and the quality of the finally formed filter cake can be obviously improved. The precision of the upper filter screen is selected according to the particle size of the material and is generally the same as that of the lower filter screen.

5) The arrangement of the upper orifice plate aims to increase the rigidity of the upper filter screen while forming the liquid accumulation cavity in the piston cover, and prevent the upper filter screen from being damaged by force under the action of hydraulic extrusion. When necessary, the stirring paddle can be additionally arranged or even attached to the washing machine, so that the purpose of on-line stirring type washing for the washing liquid is achieved, and the washing machine has a multifunctional function.

6) The arrangement of the fit clearance is used for ensuring the balance of filtrate in the effusion cavity, so that the filtrate can be uniformly and orderly discharged from the radial holes arranged on the connecting seat along the circumferential direction. The axial gap is used for preliminarily converging the filtrate in the liquid converging cavity, and finally the filtrate flows out of the vertical filter through the central pipe. The radial support ribs and the radial reinforcing ribs are used for reinforcing the strength of the corresponding parts, and the details are not repeated here.

Drawings

FIG. 1 is a state diagram of the present invention in use;

FIG. 2 is an enlarged view of a portion I of FIG. 1;

FIG. 3 is an enlarged view of a portion II of FIG. 1;

FIG. 4 is an enlarged view of a portion III of FIG. 1;

FIG. 5 is a cross-sectional view of the piston cap of the present invention;

FIG. 6 is a cross-sectional view taken along line A-A of FIG. 5;

FIG. 7 is a bottom view of FIG. 5;

FIG. 8 is a diagram of the structure of FIG. 1 in the reactive crystallization stage;

FIG. 9 is a diagram of the structure of FIG. 1 in an operating condition during a gravity dewatering phase;

FIG. 10 is a diagram of the configuration of FIG. 1 in an operational stage of hydraulic squeeze filtration dewatering;

FIG. 11 is a diagram of the FIG. 1 arrangement in a slurry wash stage;

fig. 12 is a diagram of the operation of the arrangement of fig. 1 in the cake discharge phase.

The actual correspondence between each label and the part name of the invention is as follows:

a-upper chamber b-lower chamber c-bottom layer filtrate chamber d-passing gap

e-air inlet cavity f-negative pressure cavity g-dropsy cavity h-liquid collecting cavity i-radial hole

11-piston cap 11 a-air flue 11 b-annular air uniform cavity 11 c-air hole

12-main shaft 12 a-central tube 13-expansion bag 14-connecting seat 15-pressing ring

16-upper orifice plate 17 a-stirring paddle 17 b-attached paddle 18-upper filter screen

19 a-radial support rib 19 b-radial reinforcing rib

20-frame 30-cartridge

30 a-upper cylinder 30 b-lower cylinder 30 c-coil 30 d-hollow interlayer

31-feed inlet 32-slag discharge outlet 33-liquid outlet

40-lower orifice plate 51-hydraulic cylinder 52-speed reducer 60-spray head 70-lower filter screen

80-compressed air source 90-negative pressure assembly

Detailed Description

For ease of understanding, the specific construction and operation of the invention is described further herein as follows:

when in actual use, the invention can be directly applied to the traditional vertical filter and can completely replace the traditional air pressure filtering structure. Even if the present invention is used as a piston filter press structure, the present invention has the same application effect to a horizontal filter and the like, if necessary. Of course, to specifically describe the practical application prospect of the present invention, the specific embodiments shown in fig. 1 to 12 are used herein for illustration:

in fig. 1 to 12, the vertical filter applied to the present invention mainly includes a main shaft 12, a bearing housing, a speed reducer 52, a hydraulic cylinder 51, a filter cartridge 30, and a piston cap 11. Wherein:

the filter cartridge 30 is mounted on the frame 20 as shown in fig. 1 and is formed by combining an upper cylinder 30a and a lower cylinder 30 b; the inlet port 31 is located at the top end of the upper cylinder 30a, the slag discharge port 32 is located at the side wall of the lower cylinder 30b, and the outlet port 33 is located at the bottom end of the lower cylinder 30 b. More specifically: the upper cylinder 30a is generally composed of a seal head and a straight cylinder, and is connected with the lower cylinder 30b to form a closed cavity for containing materials, which is a main place for the materials to work. The main shaft 12 is arranged coaxially with the upper cylinder 30a, passes through the upper cylinder 30a, and is connected to the speed reducer 52. The main shaft 12 can rotate driven by the speed reducer 52. The upper part of the main shaft 12 is provided with a bearing seat, two sides of the main shaft are uniformly connected with hydraulic cylinders 51, and the number of the hydraulic cylinders 51 is generally two, and the hydraulic cylinders are hydraulic power supply units for extrusion and filtration of the integrated machine. Under the action of the hydraulic cylinder 51, the main shaft 12 and the accessories fixed on the main shaft 12, such as the bearing seat and the piston cover 11, perform up-and-down motion synchronously. In order to synchronously ensure that the main shaft 12 can generate rotation and lifting actions, a bearing fit can be formed between the main shaft 12 and the hydraulic cylinder 51, and a key type meshing transmission fit can be formed between the main shaft 12 and a power output shaft of the speed reducer 52.

Further, a hollow interlayer 30d is arranged outside the filter cartridge 30, and a heat source can be introduced according to the process requirement, so that the material in the filter cartridge 30 can be heated. The hollow interlayers 30d may also be arranged to form a structure resembling a disc tube. In order to increase the heat exchange area, the bottom of the lower cylinder 30b is provided with a coil 30c for exchanging heat with the material from the bottom. As shown in fig. 4, the upper surface of the lower cylinder 30b is provided with a lower filter screen 70, the accuracy of which is selected according to the particle size of the material, and the lower filter screen plays a role in intercepting material solids and flowing away liquid, and the flowing away liquid forms mother liquid and is discharged through the liquid outlet 33. As shown in fig. 1 and 4, the lower screen 70 is fixed to the lower perforated plate 40 to increase rigidity, thereby preventing the lower screen 70 from being damaged by a hydraulic pressure. The slag hole 32 can be closed by a slag discharge cover. In the stage of slag discharging and discharging, the slag discharging cover is opened. Besides manual opening of the slag discharge cover, automatic opening or solid discharge valve can be provided.

The straight section of the upper cylinder 30a generally consists of an upper straight section and a lower straight section, and the lower straight section has a thicker wall thickness and needs to bear certain extrusion force; and secondly, fine machining is needed to obtain a higher matching size so as to form size matching with the expansion bag 13 to achieve a sealing effect. The height of the lower straight section is designed according to parameters such as effective volume, solid slag holding capacity and the like. The wall thickness of the upper straight section can be thinner, and fine machining is not needed; the difference in wall thickness between the upper straight section and the lower straight section is also one of the factors for forming the annular passage, i.e., the passing gap d, as shown in fig. 2. In addition, as shown in fig. 1, the upper cylinder 30a is provided with a feed inlet 31 at the end socket, through which the material enters the interior of the filter cylinder 30. In addition, a spray head 60 is provided, so that washing liquid enters to wash the filter cake; and simultaneously, the interior of the filter cartridge is rinsed. After the expansion bladder 13 is inflated, as shown in fig. 8, 10 and 12, it can cooperate with the lower straight section to form an annular seal, so as to seal and isolate the cavity of the filter cartridge 30, and form an upper cavity a and a lower cavity b; of course, the lower chamber b and the lower filtrate chamber c are always connected to the lower perforated plate 40 through the lower strainer 70. The inflation bladder 13 is lifted in an axial direction by the cooperation of the hydraulic cylinder 51 and the piston cap 11, so that the volumes of the upper chamber a and the lower chamber b are adjustable and variable. When the expansion bladder 13 is not inflated, as shown in fig. 9 and 11, the diameter of the outer periphery of the expansion bladder 13 is reduced, which is another factor for forming a circular passage, i.e., a passage gap d.

In the specific assembly, as shown in fig. 1, 2 and 5, the expansion bladder 13 is pressed against the outer periphery of the piston cap 11 by the lower pressing ring 15 and the upper pressing ring 15. The expansion bladder 13 may be "U" shaped to form a sealed chamber with the outer periphery of the piston cap 11. The material of the expansion bag 13 has a certain elasticity, such as various rubbers, thin-walled polytetrafluoroethylene plastics, and the like. In order to realize the inflation or deflation of the expansion bag 13, a series of air holes 11c are uniformly distributed on the outer ring of the piston cover 11, an air passage 11a is also arranged inside the piston cover 11, and the air holes 11c are communicated with the air passage 11 a. Connecting seat 14 at piston cap 11 is in the shape of a barrel with its opening facing upwards, i.e. the bottom of connecting seat 14 is closed, and its inner circumference is connected with the lower shaft end of main shaft 12 in a matching manner. The main shaft 12 is a hollow structure, and is coaxially inserted into a central tube 12a to be matched with the lumen of the main shaft 12. The bottom of the central tube 12a is provided with a sealing structure which seals the outer circumference of the central tube 12a with the tube cavity at the lower part of the main shaft 12 to form an annular air homogenizing chamber 11 b. Meanwhile, as shown in fig. 1, a rotary joint is coaxially arranged at the top end of the hollow structure of the main shaft 12, the rotary joint has two interfaces, namely an air inlet interface and an air outlet interface, and the air inlet interface is communicated with the annular air uniform cavity 11b so as to realize the air charging and discharging functions of the expansion bladder 13. Meanwhile, a negative pressure interface communicated with the negative pressure assembly 90 is arranged, and the negative pressure interface is communicated with a tube cavity of the central tube 12a, namely a negative pressure cavity f. For sealing, corresponding sealing structures are arranged at the lower end of the main shaft 12, the joint of the annular gas-homogenizing cavity 11b and the air passage 11a and other matching positions, so that the gas at the joint is prevented from leaking.

For the requirements of adjustment, control, display and the like, instruments and meters such as a regulating valve, a reversing valve, a pressure gauge and the like can be arranged between the compressed air source 80 and the air inlet interface. When the expansion bag 13 needs to be inflated to achieve the sealing effect, the compressed air source 80 provides air with a certain flow and pressure, the air enters from the air inlet port, enters the annular air uniform cavity 11b to the air hole 11c through the air passage 11a, and finally enters the U-shaped cavity body of the expansion bag 13 to promote the expansion bag 13 with certain elasticity to expand to achieve the sealing effect. And the expansion bag 13 has the functions of certain compensation and irregular cavity filling, and can achieve better sealing effect when materials exist on the sealing surface. When the expansion bag 13 needs to be exhausted to achieve the purpose of releasing the seal, the gas in the expansion bag 13 is reversed through the reversing valve, enters the annular gas homogenizing chamber 11b from the gas hole 11c to the gas channel 11a, and then reaches an exhaust interface from the gas inlet chamber e at the main shaft 12 to be exhausted. When the expansion bag 13 is exhausted and the sealing is released, the outer circumferential surface is reduced, and a passing gap d for passing the materials is exposed.

For the specific construction of the piston cap 11, reference is made to fig. 3, 5 and 6: the upper orifice plate 16 is fixedly arranged at the lower part of the piston cover 11, an annular liquid accumulation cavity g is formed by an inner cylinder at the lower part of the piston cover 11, the upper orifice plate 16 and the outer circumference of the connecting seat 14, and corresponding sealing is arranged on the outer circumferential surface of the upper orifice plate 16 to ensure the sealing of the liquid accumulation cavity g. And a layer of upper filter screen 18 with higher precision is attached to the upper orifice plate 16, the precision is selected according to the particle size of the material, the action of intercepting material solids and flowing away liquid is realized, and the flowing away liquid forms mother liquid and enters the liquid accumulation cavity g. The upper filter screen 18 is fixedly arranged on the upper hole plate 16, so that the rigidity is increased, and the upper filter screen 18 is prevented from being damaged by force under the action of hydraulic extrusion. In order to prevent the upper orifice plate 16 from deforming and damaging during hydraulic extrusion of materials, radial support ribs 19a are uniformly distributed in the liquid accumulation cavity g, the radial support ribs 19a are welded with three surfaces of the piston cover 11, and the bottom of the radial support ribs is in contact with the upper orifice plate 16 to play a supporting role. Each radial support rib 19a is chamfered to form an outer channel. Each radial support rib 19a is higher than the bottom of the connecting seat 14 to form an inner channel; the outer channel and the inner channel enable the hydrops chamber g to be communicated, and the hydrops chamber g is prevented from being separated by the radial support ribs 19 a. In addition, an axial clearance is reserved between the main shaft 12 and the barrel bottom surface of the connecting seat 14, the axial clearance forms a liquid collecting cavity h, and the liquid accumulating cavity g is communicated with the liquid collecting cavity h through a radial hole i. The liquid collecting cavity h is communicated with the cavity of the central tube 12a and finally communicated with the negative pressure interface. When the piston cover 11 is under the hydraulic action of the hydraulic cylinder, the material is gradually extruded, and the water passes through the lower filter screen 70 and finally flows away through the liquid outlet 33 through the lower hole plate 40. As the press progresses, the cake becomes thicker and more resistant to filtration, and water from the upper layer of the cake can hardly penetrate the cake and is drained away by the lower screen 70. At this time, the negative pressure assembly 90 can be opened, and under the action of suction force, the water on the upper layer of the filter cake can penetrate through the upper filter screen 18 and the upper orifice plate 16 to enter the liquid accumulation cavity g, then enter the tube cavity of the central tube 12a through the radial hole i and the liquid collection cavity h, and finally be discharged through the negative pressure port. Under the combined action of the upper filter screen 18 and the lower filter screen 70, the water content of the filter cake can be greatly reduced, and more mother liquor and drier solids can be obtained.

In addition, as shown in fig. 7, an S-shaped stirring paddle 17a is further provided at the lower orifice plate 40, the stirring paddle 17a may be a double-paddle or a triple-paddle, and the arrangement of the stirring paddle 17a is related to the turning direction of the main shaft 12, that is, during discharging, the rotation of the main shaft 12 can drive the stirring paddle 17a to drive the filter cake from the center to the periphery, and finally the filter cake is discharged from the slag discharge port 32 at the side of the lower straight section. The stirring paddle 17a in fig. 7 is a double-paddle structure, and when the main shaft 12 rotates clockwise, the stirring paddle 17a can drive the filter cake from the center to the periphery. The stirring paddles 17a can also serve the purpose of stirring and mixing in the beating washing stage. As shown in fig. 5-6, radial ribs 19b are uniformly distributed on the upper portion of the piston cap 11 to reinforce the strength of the piston cap 11 and prevent the piston cap 11 from deforming during extrusion. Meanwhile, in the reaction crystallization stage, the main shaft 12 rotates slowly, and the reinforcing ribs play roles in stirring and mixing, so that the reaction process is accelerated. If the stirring and mixing intensity of the reinforcing ribs is not enough, the auxiliary paddle 17b can be additionally arranged to enhance the mixing effect.

The following description is made in connection with each working stage of the hydraulic extrusion type all-in-one machine:

(1) the reaction crystallization stage is shown in FIG. 8.

At this time, in order to make the reaction liquid volume as large as possible, the piston cap 11 is lowered to the lowest position by the hydraulic cylinder, and the upper chamber a reaches the maximum volume. The lowest position of the piston cover 11 is determined by the stroke of the hydraulic cylinder, and it is ensured that the lower end surface of the paddle 17a does not touch the lower screen 70 at the lowest position, so as to protect the accuracy of the lower screen 70, and a certain gap is generally reserved between the two. After the piston cover 11 is lowered to the low position, the compressed air source is opened, the expansion bag 13 is inflated and keeps a certain pressure, and the sealing performance of the upper cavity a is ensured. At this time, the lower screen 70 and the upper screen 18 are both located in the lower chamber b, and are isolated from the upper chamber a, and are not affected by the crystallization of the reaction solution. And reaction liquid to be reacted and crystallized enters the upper cavity a from the feeding hole 31, and after the feeding is finished, the reaction liquid starts to react and crystallize. According to the process requirement, the reaction crystallization process can be heated, and the hollow interlayer 30d and the coil pipe 30c can be both introduced with heat sources to heat the reaction liquid in the upper cavity a. At the same time, the speed reducer 52 can be turned on, and the reaction solution can be stirred and mixed by the reinforcing ribs and the auxiliary paddles 17b on the piston cover 11. The reaction process is accelerated, and the output rotating speed of the speed reducer 52 can be adjusted through a frequency converter, so that a better stirring and mixing rotating speed is obtained. After a certain reaction time, the reaction liquid finishes the reaction crystallization process, crystal particles are separated out to form saturated suspension, the reaction crystallization process is finished, and the equipment enters the next stage.

(2) And (4) a dehydration stage. This stage can be divided into two processes, namely a gravity dewatering stage as shown in fig. 9 and a hydraulic squeeze filtration dewatering stage as shown in fig. 10.

At this time, the reaction crystallization process is finished, the reversing valve is opened, and the gas in the expansion bag 13 reversely enters the gas channel 11a through the gas hole 11c and is finally discharged through the exhaust port. The expansion bag 13 finishes air exhaust and sealing release, the outer circumferential surface of the expansion bag 13 is reduced, a passing gap d is formed between the outer circumferential surface and the inner diameter of the inner cylinder of the lower straight section, the lower cavity b is communicated with the upper cavity a, and the suspension enters the lower cavity b from the upper cavity a through the passing gap d. Under the action of gravity, the liquid in the suspension flows through the lower screen 70, passes through the lower orifice plate 40 and the liquid outlet 33, and the crystal particles are trapped on the surface of the lower screen 70 to form a filter cake, which is a self-flowing dehydration stage. When the expansion bag 13 is released, the piston cap 11 is driven by the hydraulic cylinder to rise to the highest position, which is determined by the stroke of the hydraulic cylinder. At this time, the piston cover 11 is in the upper straight section, and the passing clearance d reaches the maximum due to the difference of wall thickness between the upper straight section and the lower straight section.

When the gravity flow dehydration stage is carried out for a certain time, because the filter cake is thicker and thicker, the filtration resistance is increased, the water yield through gravity flow is smaller and smaller, at the moment, the filtration is accelerated by means of external force, and the invention starts to enter the hydraulic extrusion filtration dehydration stage: at this point, the hydraulic cylinder drives the piston cap 11 downwards, while the expansion bladder 13 inflates, creating a sealed condition, sealing the remaining suspension in the lower chamber b. Under the action of hydraulic force, the piston cover 11 gradually extrudes the material, and water passes through the lower filter screen 70 and finally flows away through the liquid outlet 33 through the lower orifice plate 40. As the press progresses, the cake becomes thicker and more resistant to filtration, and water in the upper layer of the cake is less likely to penetrate the cake and be removed by the lower screen 70. At this time, the negative pressure assembly can be opened, and under the action of suction force, the water on the upper layer of the filter cake can penetrate through the upper filter screen 18 and the upper orifice plate 16 to enter the liquid accumulation cavity g and finally be discharged from the negative pressure connector. Under the combined action of the upper filter screen 18 and the lower filter screen 70, the water content of the filter cake can be greatly reduced, and more mother liquor and drier solids can be obtained. When the stroke of the hydraulic cylinder is not changed any more and no mother liquor flows out from the negative pressure port and the liquid outlet 33, the dehydration stage is finished. The expansion bag 13 exhausts air to release the sealing state, and meanwhile, the hydraulic cylinder drives the piston cover 11 to rise to the highest position.

(3) The slurry wash stage, as shown with reference to FIG. 11:

when the dewatering stage is complete, a relatively dry cake layer is formed. If the filter cake layer needs to be washed to remove impurities, acid radicals or salts and the like so as to obtain the aim of higher purity, the method needs to enter a pulping and washing stage: at this time, the liquid outlet valve of the liquid outlet 33 is closed, the washing liquid enters from the spray header 60, the spray header 60 can be a 360-degree spray ball, can also be a common feeding pipeline, and can be set according to the process requirements; the type, the amount and the washing times of the washing liquid are also set by the process requirements. After a certain amount of washing liquid is fed, the piston cover 11 can move up and down under the action of the hydraulic cylinder, and simultaneously, the piston cover can rotate or rotate only under the driving of the speed reducer 52. The reinforcing ribs, the attached paddles 17b and the stirring paddles 17a on the piston cover 11 fully stir and mix the filter cake and the washing liquid, thereby achieving the purpose of pulping. After a certain time, pulping and washing are finished, the piston cover 11 stops acting and is reset to a high position, the liquid outlet 33 is opened, and the dehydration stage is started again.

(4) And (3) a drying stage:

if the filter cake needs to be dried, the hollow interlayer 30d and the coil 30c can be both introduced with heat sources to heat the filter cake. Meanwhile, the piston cover 11 is lowered by the hydraulic cylinder and rotated by the reducer 52. The stirring paddle 17a turns over the cake layer to accelerate the drying process. Even negative pressure drying can be performed by the negative pressure assembly. The side of the filter cartridge 30 is close to the filter cake, and a temperature monitoring and sampling port can be arranged to monitor the temperature of the filter cake and sample and analyze the filter cake. After the drying process is finished, the piston cover 11 stops and returns to the high position.

(5) The cake discharge phase, as shown with reference to fig. 12:

after the drying stage is complete, the clean filter cake needs to be removed. At this time, the slag discharge cover is opened, the piston cover 11 generates a descending motion under the action of the hydraulic cylinder, and simultaneously, the piston cover rotates under the driving of the speed reducer 52. The stirring paddle 17a gradually scrapes off the cake layer from top to bottom layer by layer, and the cake layer is driven to the cylinder wall from the center to the outside under the action of the stirring paddle 17a and finally discharged from the slag discharge port 32. The stirring paddle 17a can be in other structural types, and the stirring paddle needs to have the function of driving the materials from the center to the cylinder wall in the rotating process.

The above stages can realize the automatic and programmed operation of each stage through signals such as time setting, liquid level, weight and the like and supporting equipment such as an automatic valve, automatic feeding and the like; the monitoring of the key parts of the expansion bag 13 is realized through pressure and air quantity detection.

It will, of course, be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.

Claims

1. The utility model provides a gland for filter which characterized in that: comprises a piston cover (11) which is arranged in the filter cartridge and is used for dividing the filter cartridge into an upper cavity and a lower cavity, and a main shaft (12) which is used for driving the piston cover (11) to generate axial reciprocating motion; the bottom surface of the piston cover (11) is provided with a filter pressing surface for filter pressing materials, and the outer edge of the piston cover (11) is coaxially provided with an annular expansion bag (13) which can be inflated or filled with liquid so as to generate radial expansion and contraction actions.

2. A gland for a filter according to claim 1, wherein: a connecting seat (14) which is coaxially arranged at the piston cover (11) in a penetrating way and used for connecting the spindle (12); the connecting seat (14) is in a barrel shape with an upward barrel opening, and the bottom end of the main shaft (12) is coaxially inserted into a barrel cavity of the connecting seat (14) and forms rotation stopping fit with the barrel cavity; the main shaft (12) is a hollow shaft body, the expansion bag (13) is an air bag which is coaxially arranged at the outer edge of the piston cover (11), and air enters through the inner cavity of the main shaft (12), radially penetrates through the connecting seat (14) and enters into the bag cavity of the expansion bag (13) through an air passage (11a) preset in the piston cover (11).

3. A gland for a filter according to claim 2, wherein: the cross section of the expansion bag (13) is in a U-shaped groove shape with an opening facing to the direction of the piston cover (11), and two groove walls of the expansion bag (13) are respectively pressed and fixed at the piston cover (11) through a group of press rings (15).

4. A gland for a filter according to claim 2 or 3, wherein: the piston cover (11) is in a barrel shape with a downward barrel opening, the air passage (11a) radially extends along the barrel bottom of the piston cover (11), axially extends along the barrel wall of the piston cover (11) and is communicated to the outer annular cavity (11 b); an air hole (11c) used for communicating the cavity of the expansion bag (13) is arranged at the outer ring cavity (11 b).

5. A gland for a filter according to claim 4 wherein: an upper pore plate (16) is covered at the barrel opening of the piston cover (11), so that the upper pore plate (16) and the barrel cavity of the piston cover (11) are enclosed together to form a liquid accumulation cavity for retaining the filtrate; filtrate enters the dropsy cavity through the sieve pores of the upper pore plate (16), and then enters the central tube of the main shaft (12) through the radial holes until the filtrate is discharged out of the filter cylinder of the filter; the central tube and the tube cavity of the main shaft (12) are coaxial with each other, and an annular cavity formed by enclosing the outer wall of the central tube and the tube cavity wall of the main shaft (12) forms an air inlet cavity.

6. A gland for a filter according to claim 5 wherein: the lower plate surface of the upper orifice plate (16) is provided with a stirring paddle (17a) which plays a role of stirring in an axial direction; the stirring paddle (17a) is S-shaped; an auxiliary paddle (17b) is arranged on the top surface of the piston cover (11).

7. A gland for a filter according to claim 6 wherein: an upper filter screen (18) is attached to the bottom plate surface of the upper orifice plate (16); the filtering holes at the upper filtering screen (18) are communicated with the sieve pores at the upper pore plate (16), and the aperture of the filtering holes is smaller than that of the sieve pores.

8. A gland for a filter according to claim 5 wherein: in the axial direction of the main shaft (12), a fit clearance for filtrate to pass through is reserved between the upper orifice plate (16) and the connecting seat (14).

9. A gland for a filter according to claim 5 wherein: radial supporting ribs (19a) are arranged in the liquid accumulation cavity, and radial reinforcing ribs (19b) are further arranged on the top surface of the piston cover (11).

10. A gland for a filter according to claim 5 wherein: an axial gap is reserved between the main shaft (12) and the bottom surface of the connecting seat (14), the axial gap forms a liquid collecting cavity, and the radial hole is communicated with the liquid accumulating cavity and the liquid collecting cavity.