JP2007021453A - Remaining filtrate recovery system used for rotary strainer and method for recovering remaining filtrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid blowing back of a filtrate remaining in a rotary drum 1 and a filter part by a blow gas to a cake layer C' when the cake layer is removed, which causes the increased filtrate content of the cake layer C', the deteriorated cake layer, and wasting of the useful filtrate, as in the cases of conventional rotary single chamber type strainers. <P>SOLUTION: The remaining filtrate recovery system 40 is used for a rotary single chamber type strainer 20 provided with a rotary drum 21, center pipe 22, undiluted solution bat 23, and a first valve shoe 25 and is a system for recovering by suction a filtrate remaining in the cake layer C' on the rotary drum 21. The system 40 is provided with a suction part 41 (for recovering the remaining filtrate) which is connected to the center pipe 22 while leaving interstices between the suction part 41 and the inner peripheral surface of the rotary drum 21, a second vacuum pump 42 connected to the suction part 41 via the center pipe 22, and a remaining filtrate separator 43 for recovering the remaining filtrate from the suction part 41 via the second vacuum pump 42. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a residual filtrate recovery apparatus and a residual filtrate recovery method used in a rotary filter, and more specifically, a residual filtrate recovery apparatus for recovering a filtrate remaining in a cake layer formed on the surface of a filtration part and a filtration part, and The present invention relates to a method for recovering a residual filtrate.

  For example, a rotary single-chamber filter is mainly composed of a rotary drum having a single filtration chamber. This rotary single-chamber filter has a high filtration capacity due to the large opening ratio of the rotary drum and the diameter of the filtrate tube, a high cleaning effect of the cake layer formed on the filtration part of the rotary drum, and a filter cloth. General chemical industry, fertilizer because there are many advantages such as easy-peeling even with a difficult-to-filter thin cake layer by blowing gas from the backside, and easy structure and maintenance due to simple structure It is used in many fields such as industry, metal industry and food industry.

  A conventional rotary single chamber filter will be described with reference to FIG. As shown in FIG. 2, this rotary single-chamber filter (hereinafter simply referred to as “filter”) is a variable speed reducer in which both end surfaces are sealed and a large number of filtrate holes are formed on the peripheral surface. A rotary drum 1 that is rotationally driven by a motor (not shown), a center pipe 2 that rotatably supports the rotary drum 1, and a stock bat 3 disposed below the rotary drum 1 are provided. A filter cloth is stretched around the outer peripheral surface of the rotating drum 1 as a filtering part through a filter bridge (not shown), and the lower part of the rotating drum 1 is immersed in the stock solution slurry F filled with the stock solution vat 3 to thereby filter the filtration region. During the rotation of the rotating drum 1, a cake layer made of solid components of the raw slurry F is formed on the surface of the filter cloth in the filtration region, and the filtrate permeates the filter cloth and enters the rotating drum 1, and the center pipe 2 The filtrate in the rotary drum 1 is sucked by a vacuum device (not shown) through the filtrate tube 4 connected to the outside and led out of the apparatus.

  A plurality of valve shoes 5 made of synthetic resin such as tetrafluoroethylene resin are disposed in the rotating drum 1 along the axial direction of the center pipe 2, and slide on the inner peripheral surface of the rotating drum 1 through a slit. Touching. Narrow first and second slits are formed in the upper and lower portions of the valve shoe 5 along the axial direction of the rotary drum 1, and blown gas such as nitrogen gas is blown out from these slits to filter the filter cloth. After the cake layer is peeled from the inside, the clogging is eliminated by washing.

  That is, the first slit of the valve shoe 5 is connected to the center pipe 2 via the valve bar 6, and blow gas such as nitrogen gas supplied to the center pipe 2 is blown from the first slit to peel off the cake layer on the surface of the filter cloth. . Between the first slit and the second slit, a filter cloth cleaning spray 9A disposed outside the rotary drum 1 is disposed, and the filter cloth cleaning spray 9A is directed slightly above the second slit of the rotary drum 1. The cleaning liquid is sprayed at high speed to clean the filter cloth after the cake layer is peeled off, and impurities on the surface of the filter cloth are cleaned and removed. Further, the second slit at the lower part of the valve shoe 5 is connected to a header pipe 8 branched from a cleaning pipe (not shown) in the center pipe 2 through a flexible tube 7, and blow gas such as nitrogen gas is passed through the second slit. Blowing and removing the clogging of the filter cloth by removing the clogging of the filter cloth by high-speed jetting of the cleaning liquid. In FIG. 2, C is a cake peeled from the filter cloth, 9B is a cake washing spray disposed outside the rotary drum 1, and the cake layer formed on the filter cloth is washed with the cake washing spray 9B. To do. Reference numeral 10 denotes a chute for discharging the cake out of the machine.

  Next, a conventional filtration method using the rotary single chamber filter will be described. For example, when the rotating drum 1 rotates counterclockwise as shown in FIG. 2, the stock slurry F in the stock solution vat 3 is sucked in the filtration region of the rotating drum 1 to form a solid component as a cake layer on the filter cloth surface. At the same time, the filtrate is accumulated in the rotary drum 1. The filtrate is led out of the machine from the filtrate pipe 4 through the center pipe 2 by a vacuum device (not shown). On the other hand, as the rotating drum 1 rotates, the cake layer comes out of the stock slurry F to the outside and is gradually drained and washed while passing under the cake washing spray 9B. When the cake layer after washing reaches the valve shoe 5 as the rotating drum 1 rotates, the blow gas from the first slit blows out from the inside of the filter cloth via the filtrate hole and the filter bridge of the rotating drum 1. And the cake C is discharged out of the machine through the chute 10. The part from which the cake layer has been peeled is cleaned by the cleaning liquid from the filter cloth cleaning spray 9A and then reaches the second slit, and the blow gas from the second slit passes through the space in the filter bridge of the rotary drum 1 to pass through the filter. It blows out from the many holes of the bridge to the inner surface of the filter cloth, and removes impurities remaining on the filter cloth. After that, it reaches into the stock solution slurry F, and the next filtration is performed. In a series of filtrations, the filtration capacity can be increased by increasing the rotational speed of the rotary drum 1.

  However, in the case of a conventional rotary single-chamber filter, the pressure in the rotary drum 1 is reduced, the stock slurry F is suction filtered to form a cake layer, the cake layer is washed, and then the cake layer is removed from the rotary drum. However, the filtrate cannot be sufficiently removed from the cake layer by the degree of vacuum in the rotary drum 1 until the cake layer is peeled off. Moreover, since the filtrate which permeated by capillary action etc. remains in the slits of the rotary drum 1 and the filtration part (filter bridge, filter cloth and rotary drum itself) on the outer peripheral surface thereof, these residual filtrates cause the cake layer. Accompanying the blow gas when peeling off, blow off the residual filtrate back to the cake layer, newly add the residual filtrate into the cake layer, increase the filtrate content of the cake layer, worsen the cake layer after devolatilization I will let you.

  When the residual filtrate in the cake layer increases, the load of the subsequent drying process increases and the drying cost increases. Further, if the filtrate itself is beneficial and expensive, it is necessary to increase the recovery efficiency of the residual filtrate. However, at present, the recovery efficiency of the filtrate is reduced by blowing the filtrate back to the cake layer with blow gas.

  The present invention has been made in order to solve the above-mentioned problems, and is capable of recovering the filtrate remaining from the cake layer to the rotating drum without waste and preventing the residual filtrate from being blown back to the cake layer. It aims at providing the residual filtrate collection | recovery apparatus and residual filtrate collection | recovery method which are used for a type | formula filter.

  In the residual filtrate collecting apparatus according to claim 1 of the present invention, a rotating drum having a filtration part formed on the outer peripheral surface is pivotally attached to a center pipe, and a part of the rotating drum is immersed in a stock solution vat to obtain a stock solution slurry. Suction filtered, the filtrate is discharged out of the machine through a filtrate pipe connected to the center pipe, and blown out from a valve shoe connected to the center pipe and having a slit between the inner peripheral surface of the rotary drum. A device that is used in a rotary filter that peels the cake layer formed on the outer peripheral surface of the filtration unit with gas, and that collects residual filtrate remaining from the cake layer across the rotary drum by suction in the rotary drum A residual filtrate suction section connected to the center pipe and having a gap between the inner peripheral surface of the rotary drum and the suction section connected to the suction section via the center pipe. A sheet discharge apparatus, is characterized in that and a container for recovering the residual filtrate from the suction unit through the supply and exhaust device.

  According to a second aspect of the present invention, there is provided the residual filtrate collecting apparatus according to the first aspect, wherein the suction portion is disposed upstream of the valve shoe with respect to the rotational direction of the rotating drum. It is characterized by being.

  According to a third aspect of the present invention, there is provided a method for recovering a residual filtrate, wherein a part of a rotating drum having a filtration part formed on an outer peripheral surface thereof is used as a stock solution slurry in a stock solution vat with a center pipe of a rotary filter as a center of rotation. Rotating in a dipped state, the raw slurry is filtered by suction, and the filtrate is discharged from the filtrate pipe connected to the center pipe to the outside of the machine, and connected to the center pipe and between the inner peripheral surface of the rotary drum. When the cake layer formed on the outer peripheral surface of the filtration part is peeled off by blowing gas from a valve shoe with a slit interposed between them, residual filtrate remaining over the rotary drum from the cake layer is removed in the rotary drum. In which the residual filtrate is sucked with a suction part arranged on the upstream side of the valve shoe with reference to the rotational direction of the rotary drum, Liquid and is characterized in that the recovered discharged to the outside through the center pipe into the container.

  According to the first to third aspects of the present invention, the remaining filtrate from the cake layer to the rotating drum can be recovered without waste, and the remaining filtrate can be prevented from being blown back to the cake layer. It is possible to provide a residual filtrate recovery apparatus and a residual filtrate recovery method used in a rotary filter that can be used.

  Hereinafter, the present invention will be described based on the embodiment shown in FIG. FIG. 1 is a block diagram showing a filtration system to which an embodiment of the residual filtrate recovery apparatus of the present invention is applied.

  A filtration system to which the residual filtrate recovery device of this embodiment is applied is configured as shown in FIG. 1, for example. That is, the filtration system includes a rotary single-chamber filter 20 and a residual filtrate recovery device 40 attached to the rotary single-chamber filter 20. The rotary single chamber filter 20 includes a rotary drum 21, a center pipe 22, a stock solution bat 23, a filtrate tube 24, a first valve shoe 25, a first valve bar 26, a cake washing spray 27, and a cake discharge chute 28. Basically, it is configured according to the conventional art. On the outer peripheral surface of the rotating drum 21, a filtration portion is formed that is configured by a filter cloth stretched over a whole surface via a filter bridge. A cleaning liquid supply source (not shown) is connected to the cake cleaning spray 27 via a pipe 27 </ b> A. A predetermined cleaning liquid is supplied from the cleaning liquid supply source, and the cake layer is formed by the cleaning liquid sprayed from the cake cleaning liquid spray 27. Wash C ′. The rotating drum 21 is sealed in the casing.

  As shown in FIG. 1, the residual filtrate recovery device 40 is connected to the center pipe 22 and has a suction part 41 for residual filtrate with a gap between the inner peripheral surface of the rotary drum 21 and the center pipe 22. And a suction / exhaust device (for example, a second vacuum pump) 42 connected to the suction part 41, and a residual filtrate separator 43 for recovering the residual filtrate from the suction part 41 via the vacuum pump 42, and a cake layer C The residual filtrate remaining over the rotary drum 21 is sucked and collected.

  As shown in FIG. 1, the suction portion 41 has a second valve shoe 41 </ b> A and a second valve bar 41 </ b> B, and a slit is formed between the second valve shoe 41 </ b> A and the inner peripheral surface of the rotary drum 21, The drum 21 is configured to be slidably contacted with the inner peripheral surface of the drum 21, and is arranged over the entire axial length of the inner peripheral surface of the rotating drum 21, and extends from the slit of each second valve shoe 41 </ b> A to the entire inner peripheral surface of the rotating drum 21. The residual filtrate can be sucked. As the suction portion 41, for example, one having substantially the same configuration as the first valve shoe 25 and the first valve bar 26 is used. The suction portion 41 is connected to the center pipe 22 at a position offset in the counterclockwise direction from the first valve shoe 25 and the first valve bar 26. The inside of the center pipe 22 is divided into three rooms 22A, 22B, and 22C by, for example, three partition walls arranged along the axial direction. A filtrate tube 24 is connected to the first chamber 22A, and a first valve bar 26 is connected to the second chamber 22B. A suction part 41 is connected to the remaining third chamber 22C.

  A residual filtrate separator 43 and a second vacuum pump 42 are connected to the third chamber 22C from the upstream side to the downstream side of the residual filtrate via a pipe 44A, and the suction part 41 is connected by the exhaust action of the second vacuum pump 42. The air is sucked from the outside of the rotary drum 21 through. Since the suction portion 41 is so close that the second valve shoe 41A is in sliding contact with the inner peripheral surface of the rotary drum 21, when the inside is depressurized via the second vacuum pump 42, the rotary drum 21 is rotated from the cake layer C '. The filtrate remaining over 21 can be aspirated. The residual filtrate sucked by the suction part 41 is collected in the residual filtrate separator 43 from the third chamber 22C through the pipe 44A. A second suction pump 45 is connected to the residual filtrate separator 43 via a pipe 44B, and the second suction pump 45 sends the residual filtrate extracted from the residual filtrate separator 43 to a filtrate collection tank (not shown). is there. The discharge side of the second vacuum pump 42 is connected to the second chamber 22B of the center pipe 22 via a pipe 44C, and air sucked from the outside of the rotary drum 21 is supplied to the second chamber 22B.

  The second vacuum pump 42 depressurizes the inside of the suction portion 41 to form a vacuum state, and this degree of vacuum is higher than that in the rotary drum 21. Since the suction part 41 has a higher vacuum than that in the rotary drum 21, the filtrate that cannot be sucked in the rotary drum 21 and remains on the inner peripheral surface of the rotary drum 22 from the cake layer C ′ is removed by suction. And the remaining filtrate can be recovered.

  Thus, since the residual filtrate collection | recovery apparatus 40 can remove and collect | recover the filtrate remaining over the internal peripheral surface of the rotating drum 22 from the cake layer C 'from the suction part 41, it can collect | recover of the rotating drum 21. When the cake layer C ′ formed in the filtration part reaches the first valve shoe 25 via the suction part 41, most of the filtrate remains in the part from the filtration part to the inner peripheral surface of the rotary drum 21. Therefore, even if blow gas is blown out from the first valve shoe 25, there is no blow back of the residual filtrate from the rotary drum 21 and the filtration part, and the filtrate of the cake layer C ′ after dewatering is increased to increase the cake layer C ′. Will not make it worse.

  Further, as shown in FIG. 1, a filtrate separator 29, a mist separator 30 and a first vacuum pump 31 are connected to the first chamber 22A of the center pipe 22 from the upstream side to the downstream side of the filtrate via a pipe 32A. The first vacuum pump 31 collects the filtrate from the filtrate tube 24 to the filtrate separator 29 via the first chamber 22A in the center pipe 22. The mist-like filtrate that is not collected in the filtrate separator 29 is collected in the mist separator 30. A first suction pump 33 is connected to the filtrate separator 29 and the mist separator 30 via a pipe 32B. The filtrate in these separators 29 and 30 is appropriately extracted and sent to a filtrate collection tank (not shown). is there.

  The discharge side of the first vacuum pump 31 is connected to the second chamber 22B of the center pipe 22 via the pipe 32C, and merges with the air discharged from the first vacuum pump 31 into the second chamber 22B. Then, air is blown out toward the rotary drum 21 as blow gas through the first valve bar 26 and the first valve shoe 25, and the cake layer C ′ formed in the filtration part of the rotary drum 21 is peeled off. . In addition, if nitrogen gas etc. are used as blow gas, blow gas, such as nitrogen gas, will circulate within a casing.

  Next, the operation will be described. The steps from the filtration of the stock slurry F and the washing of the cake layer C ′ from the outside of the rotary drum 21 are the same as in the prior art, so the description thereof is omitted, and the step of sucking the residual filtrate from the cake layer C ′ will be described. . When the rotary drum 21 reaches the suction part 41 of the residual filtrate collecting device 40, the suction part 41 is in a reduced pressure state (a reduced pressure state with a higher degree of vacuum than in the rotary drum 21) by the second vacuum pump 42, and Since the two-valve shoe 41A is so close that it comes into sliding contact with the inner peripheral surface of the rotary drum 21, air is sucked mainly from the outer side of the rotary drum 21, that is, from the outer peripheral surface of the cake layer C ′.

  The suction part 41 not only collects the filtrate that cannot be collected by the rotating drum 21 but also remains in the cake layer C ′ itself, as well as the filtrate remaining on the outer peripheral surface of the rotating drum 21 and the slits of the rotating drum 21. The residual filtrate is sucked from the second valve shoe 41A. This residual filtrate is recovered by the second vacuum pump 42 to the residual filtrate separator 43 via the third chamber 22C of the center pipe 22 and the pipe 44A. The second vacuum pump 42 supplies discharge air to the second chamber 22B of the center pipe 22 through the pipe 44C.

  When the rotating drum 21 rotates and passes the suction part 41 and reaches the first valve shoe 25, the cake layer C ′ is peeled off from the outer peripheral surface of the filtering part of the rotating drum 21 by the air blown out from the first valve shoe 25. When air is blown out from the first valve shoe 25, the residual filtrate has already been removed and collected from the slits of the rotary drum 21 and the filtration unit by the suction unit 41, so that the remaining filtrate does not remain. Without being blown back, the cake layer C ′ is peeled off from the filtration part as cake C without deteriorating the properties of the cake layer C ′ after draining.

  As described above, according to the present embodiment, a part of the rotary drum 21 having the filtration part formed on the outer peripheral surface with the center pipe 22 of the rotary single chamber filter 20 as the rotation center is used as the raw solution in the raw solution bat 23. The stock solution F is rotated while being immersed in the slurry F, and the filtrate is sucked and filtered, and the filtrate is discharged from the filtrate tube 24 connected to the first chamber 22A of the center pipe 22 to the outside, while the second of the center pipe 22 is discharged. When the blow gas is blown out from the first valve shoe 25 that is connected to the chamber 22C and has a slit between the inner peripheral surface of the rotary drum 21 and the cake layer C ′ on the outer peripheral surface of the filtration portion is peeled off, the rotary drum The suction portion 41 disposed upstream of the first valve shoe 25 with respect to the rotation direction of the first valve shoe 25 sucks the remaining filtrate from the cake layer C ′ over the inner peripheral surface of the rotary drum 21 to the outside of the machine. To recover discharged to the residual filtrate separator 43, if useful and expensive filtrate, can be effectively recovered without wastefully discharged together with the cake C '. Further, the blown gas that blows out the residual filtrate from the first valve shoe 25 toward the cake layer C ′ does not contain the residual filtrate, and the residual filtrate does not blow back to the cake layer C ′. Therefore, the cake C ′ peeled from the filtration part of the rotary drum 21 has a small amount of filtrate, and the processing cost of the drying process can be reduced.

  In the above embodiment, the first and second vacuum pumps 31 and 42 are also used as means for blowing out blow gas. However, the first and second vacuum pumps 31 and 42 are used exclusively for evacuation. In order to blow air from the valve shoe 25, a dedicated compressor may be used. In the above-described embodiment, air has been described as an example of the blow gas. However, an inert gas such as nitrogen gas may be used in accordance with the chemical characteristics of the raw slurry. Moreover, although the said embodiment demonstrated the case where the suction part 41 was provided separately from the 1st valve shoe 25 and the 1st valve bar 26, these both were united and it used for blowing out and suction | inhalation in one valve shoe and a valve bar. It may be provided with a passage for use.

  The present invention can be widely applied to rotary filters in many fields such as general chemical industry, fertilizer industry, metal industry, and food industry.

It is a block diagram which shows the filtration system to which one Embodiment of the residual filtrate collection | recovery apparatus of this invention is applied. It is sectional drawing which shows an example of the conventional rotary single chamber type filter.

Explanation of symbols

20 Rotating Single Chamber Filter 21 Rotating Drum 22 Center Pipe 23 Stock Solution Vat 24 Filtrate Tube 25 First Valve Shoe 40 Residual Filtration Recovery Device 41 Suction Unit 42 Second Vacuum Pump (Supply / Exhaust Device)
43 Residual filtrate separator (container)

Claims (3)

  A rotating drum having a filtration part formed on the outer peripheral surface is attached to a center pipe, a part of the rotating drum is immersed in a stock solution vat to suck and filtrate the stock solution slurry, and the filtrate is passed through a filtrate tube connected to the center pipe. The cake layer formed on the outer peripheral surface of the filtration part is peeled off by the gas blown out from the valve shoe connected to the center pipe and having a slit between the inner peripheral surface of the rotary drum and discharged from the machine. A device for sucking and collecting residual filtrate remaining from the cake layer across the rotary drum in the rotary drum, wherein the residual filtrate is connected to the center pipe and is connected to the inner periphery of the rotary drum. A suction portion for residual filtrate with a slit interposed between the surface, a supply / exhaust device connected to the suction portion via the center pipe, and the above-mentioned via the supply / exhaust device. Residual filtrate recovery apparatus characterized by comprising a container for recovering the residual filtrate from 引部, the.   The residual filtrate recovery device according to claim 1, wherein the suction unit is disposed on the upstream side of the valve shoe with reference to the rotation direction of the rotary drum.   Using the center pipe of the rotary filter as the center of rotation, rotating a part of the rotating drum with the filtration part formed on the outer peripheral surface immersed in the stock solution slurry in the stock solution bat, suction filtration of the stock solution slurry, While the filtrate is discharged from the filtrate pipe connected to the center pipe to the outside of the machine, gas is blown out from a valve shoe connected to the center pipe and having a gap between the inner peripheral surface of the rotating drum and the filtration unit. When peeling the cake layer formed on the outer peripheral surface, the residual filtrate remaining over the rotating drum from the cake layer is sucked and collected in the rotating drum, and the rotating direction of the rotating drum is The residual filtrate is sucked with a suction part arranged on the upstream side of the valve shoe with reference to the above, and the residual filtrate is discharged out of the machine through the center pipe. Residual filtrate recovery method comprising recovering the inner.

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