JP2002191912A - Single chamber type rotary filter machine and filtering method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single chamber type rotary filter machine and a filtering method and to enhance filtering efficiency by preventing the clogging of filter cloth. SOLUTION: The single chamber type rotary filter machine is equipped with a rotary drum 1, a center pipe 2 and a raw liquid vat 3 and constituted so that the cake layer C on the outer surface of the filter cloth 14 is peeled and recovered by the flow gas from the first slit 5A provided to the upper part of the valve shoe 5, which is connected to the center pipe and provides a small gap with respect to the inner peripheral surface of the rotary drum, and the impurities of the filter cloth 14 are removed by the flow gas from the second slit 5B provided to the lower part of the valve shoe 5. A first liquid spray 15 for spraying a liquid is mounted on the center pipe 2 for supplying the flow gas to the first slit 5A and a second liquid spray 16 for spraying a liquid is mounted on a washing conduit 8 for supplying the flow gas to the second slit 5B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary single-chamber filter and a filtering method, and more particularly, to a rotary single-chamber filter and a filtering method for preventing clogging of a filter cloth and improving filtration efficiency. About.

[0002]

2. Description of the Related Art A rotary single-chamber type filter has a filtration chamber mainly composed of a single-chamber rotary drum, and has a large filtration rate due to a large opening ratio of a drum and a large diameter of a filtrate tube. The cleaning effect is high because a uniform flow of the cleaning liquid can be maintained, and the filter cloth is efficiently blown back from the back surface by the blowback air, so that even a thin cake layer that is difficult to filter can be easily peeled off. It is used in many fields such as general chemical industry, fertilizer industry, metal industry, and food industry, because it has many advantages such as simple and low maintenance and easy maintenance.

A conventional rotary single-chamber type filter will now be described with reference to FIG. As shown in the figure, this rotary single-chamber type filter (hereinafter simply referred to as "filter") is a variable speed reducer in which both ends are sealed and a number of filtrate holes are formed on a peripheral surface. The rotary drum 1 includes a rotary drum 1 that is driven to rotate by a motor (not shown), a center pipe 2 that rotatably supports the rotary drum 1, and a stock vat 3 that is disposed below the rotary drum 1. A filter cloth (not shown) is stretched on the outer peripheral surface of the rotary drum 1 via a filter bridge (not shown).
Is immersed in the stock solution slurry F filled with the water, a filtration region is formed, and a cake layer composed of the solid component of the stock solution slurry F is formed on the surface of the filter cloth in the filtration region while the rotary drum 1 rotates, and the filtrate is formed. The filter cloth penetrates into the rotary drum 1 through the filter cloth, and the filtrate in the rotary drum 1 is sucked by a filtrate pipe 4 connected to the center pipe 2 by a vacuum device (not shown) and led out of the machine.

A plurality of valve shoes 5 made of a synthetic resin such as Teflon (registered trademark) are provided in the rotary drum 1 along the axial direction of the center pipe 2, and a small gap is formed on the inner peripheral surface of the rotary drum 1. There is sliding contact. Narrow first and second slits (not shown) are formed in the upper and lower portions of the valve shoe 5 along the axial direction of the rotary drum 1. Blow gas or the like is ejected from these slits to filter the filter cloth. Washing is performed from the inside of the rotating drum 1 to prevent the clogging. Therefore, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 10-2164.
The method of preventing clogging proposed in No. 20 will be described below.

That is, the first slit of the valve shoe 5 is connected to the center pipe 2 through the valve bar 6,
Blow gas such as nitrogen gas supplied to the center pipe is blown from the first slit to peel off the cake layer on the surface of the filter cloth. A filter cloth cleaning spray 9A disposed outside the rotary drum 1 is disposed between the first slit and the second slit, and is directed slightly upward from the filter cloth cleaning spray 9A to the second slit 5B of the rotary drum 1. Then, the washing liquid is sprayed at high speed to wash the filter cloth after the cake layer is peeled off, and impurities on the surface of the filter cloth are washed and removed. Further, a second slit below the valve shoe 5 is connected to a header pipe 8A 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 supplied from the second slit. Blowing and high-speed injection of the washing liquid removes foreign substances clogged in the filter holes of the filter cloth, thereby preventing the filter cloth from being clogged. In FIG. 4, C is a cake peeled off from the filter cloth, 9B is a spray for cleaning the cake disposed outside the rotary drum 1, and the cake layer formed on the filter cloth is washed by the spray 9B for cleaning the cake. I do. Reference numeral 10 denotes a chute for discharging the cake outside 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. 4, the stock solution slurry F in the stock solution vat 3 is sucked in the filtration area of the rotating drum 1 to form a solid component as a cake layer on the surface of the filter cloth. At the same time, the filtrate accumulates in the rotating drum 1. The filtrate is drawn out from the filtrate pipe 4 through the center pipe 2 by a vacuum device (not shown). On the other hand, with the rotation of the rotary drum 1, the cake layer goes out of the stock slurry F to the outside and is gradually drained, and is washed while passing below the cake washing spray 9B. When the washed cake layer reaches the valve shoe 5 with the rotation of the rotating drum 1, the blow gas from the first slit blows out from the inside of the filter cloth through the filtrate hole and the filter bridge of the rotating drum 1 to form the cake. The layer is peeled off, and the cake C is discharged out of the machine via the chute 10. The portion from which the cake layer has been peeled is washed by the washing liquid from the filter cloth washing spray 9A and then reaches the second slit, where the blow gas from the second slit passes through the space in the filter bridge of the rotary drum 1 and is filtered. A large number of holes in the bridge squirt into the inside of the filter cloth to remove impurities remaining on the filter cloth. Thereafter, the solution reaches 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 rotation speed of the rotary drum 1.

[0007]

However, in the case of the above-mentioned conventional rotary single-chamber type filter, the blow gas from the first slit of the valve shoe 5, the cleaning liquid from the filter cloth cleaning spray 9A and the valve shoe are used. 5, the clogging of the filter cloth is prevented by using the blow gas from the second slit. However, in some cases, the clogging of the filter cloth is caused in a relatively short time, and the operation is stopped to reduce the filtration efficiency. There was a problem that the number of times of washing of all filter cloths increased.

The present invention has been made to solve the above-mentioned problems, and is effective for reslurrying a peeled cake. In any case, clogging of a filter cloth after peeling a cake layer is performed. It is an object of the present invention to provide a rotary single-chamber filter and a filtration method that can reliably prevent the occurrence of filtration and maintain high filtration efficiency over a long period of time.

[0009]

According to a first aspect of the present invention, there is provided a rotary single-chamber filter, wherein a rotary drum having a filter cloth stretched on an outer peripheral surface thereof is mounted on a center pipe via a filter bridge. The lower part of the rotary drum is immersed in a stock vat to suction-filter the stock slurry, and the filtrate is led out of the machine by a filtrate pipe connected to a center pipe, and connected to the center pipe and between the inner peripheral surface of the rotary drum. The cake layer formed on the outer surface of the filter cloth is peeled and collected by the first gas blown from the first slit at the upper portion of the valve shoe having a small gap, and is blown from the second slit at the lower portion of the valve shoe. A rotary single-chamber filter for removing impurities from the filter cloth by a second gas, wherein a first liquid is sprayed on the center pipe for supplying the first gas. With mounting the fog unit, the second
A second liquid spray means for spraying a second liquid is mounted on a pipe for supplying gas.

[0010] In the filtration method according to a second aspect of the present invention, the undiluted slurry in the undiluted solution vat is filtered while rotating a rotating drum having a filter cloth stretched on an outer peripheral surface thereof through a filter bridge around a center pipe. And the filtrate is led out of the machine through the center pipe, and the first gas is blown from the first slit at the top of the valve shoe, which communicates with the center pipe and has a small gap with the inner peripheral surface of the rotary drum, and the cake on the outer surface of the filter cloth is removed. In a filtration method using a rotary single-chamber filter, the layer is separated and collected, and a second gas is blown from a second slit below the valve shoe to remove impurities from the filter cloth. After the first liquid is sprayed on to adjust as a first gas-liquid mixed fluid, the first gas-liquid mixed fluid is blown from the first slit to peel off the cake layer, After the second liquid is sprayed on the two gases and adjusted as a second gas-liquid mixed fluid, the second gas-liquid mixed fluid is blown from the second slit to wash the filter cloth. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. FIG. 1 is a sectional view of a principal part showing an embodiment of a rotary single-chamber type filter of the present invention, and FIG. 2 shows a mechanism for preparing first and second gas-liquid mixed fluids shown in FIG. FIG. 3 is a plan view from the direction of the line III-III in FIG.

The rotary single-chamber filter according to the present embodiment comprises a rotary drum 1, a center pipe 2, a stock vat 3, a filtrate tube 4, a valve shoe 5, a valve bar 6, a flexible tube 7, Pipe, header pipe 8A, washing spray 9 and cake discharging chute 10
It is provided with.

As shown in FIGS. 1 and 2, a plurality of valve shoes 5 are arranged inside the rotary drum 1 along the axial direction, and each of the valve shoes 5 has a small gap with the inner peripheral surface of the rotary drum 1. Are located. A narrow first slit 5A is formed in the upper part of the valve shoe 5 along the axial direction. A valve bar 6 is connected to the first slit 5A and communicates with the center pipe 2. A narrow second slit 5B is formed in the lower part of the valve shoe 5 along the axial direction, and the flexible tube 7 is connected to the second slit 5B. The flexible tube 7 is connected to a header pipe 8A branched from a washing conduit 8 mounted in the center pipe 2 along the axial direction.
Further, a cleaning liquid spray 13 is provided outside the rotating drum 1, and the cleaning liquid is sprayed at a high speed from the spray nozzle 13 </ b> A slightly above the second slit 5 </ b> B of the rotating drum 1.

Also, as shown in FIG.
A plurality of filter bridges 11 are arranged along the entire circumference in the circumferential direction, and a narrow space 12 is formed between the inner surface of each filter bridge 11 and the outer circumferential surface of the rotating drum 1. In this filter bridge 11, a number of small holes (not shown) are formed evenly distributed over the entire surface. A large number of filtrate holes 1A are formed at equal intervals in the axial direction on the peripheral wall of the rotary drum 1, and are arranged at equal intervals in the circumferential direction. Then, for example, two rows of filtrate holes 1 </ b> A in the circumferential direction are arranged in each filter bridge 11. In addition, a filter cloth 1
4 is extended and integrated with the filter bridge 11.

Further, in the present embodiment, as shown in FIGS. 1 to 3, a first liquid spraying spray 15 is mounted on the blind flange 2A at the end of the center pipe 2 as first liquid spraying means. The first liquid spraying spray 15 includes, for example, a nozzle 15A and a pipe 15 having the nozzle 15A at its tip.
B, for example, is inserted along the axial direction of the center pipe 2 from a position slightly offset from the center of the blind flange 2A as shown in FIG. And nozzle 1
5A is located more inward than the blow gas inlet 2B. Therefore, when the liquid is sprayed from the first liquid spraying spray 15, the spray fine particles of the liquid and the blow gas are mixed and the first liquid is sprayed.
As a gas-liquid mixed fluid, it flows through the center pipe 2 and is blown from the first slit 5A of the valve shoe 5 to separate the cake layer from the rotary drum 1 while reslurrying the cake layer.
The liquid is contained in the gas-liquid mixed fluid in an amount necessary for peeling the cake layer and washing the filter cloth. The liquid can be appropriately selected according to the material of the cake layer. For example, when the cake layer is made of isophthalic acid, acetic acid is used as the liquid.

The blind flange 2A of the center pipe 2
A second liquid spraying spray 16 is mounted as second liquid spraying means from a direction perpendicular to the washing conduit 8 extending in the axial direction from the center of the washing liquid. Second liquid spray spray 16
As shown in FIG. 3, for example, a nozzle 16A and a pipe 16B having the nozzle 16A at the tip thereof are inserted from a blind flange 8C that closes a branch pipe 8B of the cleaning conduit 8. The ejection port of the nozzle 16A is disposed substantially at the axis of the cleaning conduit 8, and sprays the liquid downstream of the cleaning conduit 8. Therefore, when supplying the cleaning medium from the second slit 5B of the valve shoe 5, the second liquid spray 1
When the liquid is sprayed into the blow gas flowing through the cleaning conduit 8 from the nozzle 16A of No. 6, the blow gas and the spray fine particles are mixed to form a second gas-liquid mixed fluid, which is blown from the second slit 5B.

The gas-liquid volume ratio (gas / liquid) of the second gas-liquid mixed fluid is preferably in the range of, for example, 100/1 to 100/20. If the amount of the liquid is less than the above range, it is not possible to expect the effects of the liquid described below.
In addition, even if the amount of the liquid is larger than the above range, the function and effect corresponding to the amount cannot be expected, and there is a possibility that the liquid forms droplets in the cleaning conduit 8 and accumulates as the liquid. Further, the volume ratio (gas / liquid) of the gas and liquid of the first gas-liquid mixed fluid may contain a liquid several times (2 to 5 times) the liquid of the second gas-liquid mixed fluid, for example. preferable. If the amount of the liquid is less than this range, the effect of washing the filter cloth is small, and if it is more than this range, peeling of the cake layer may be hindered.

As is clear from FIG. 1, when the first slit 5A is displaced from the filtrate hole 1A of the rotary drum 1, the second slit 5B coincides with the filtrate hole 1A and the space 12 When the first slit 5A coincides with the filtrate hole 1A, the two slits 5A and 5A are separated from the filtrate hole 1A.
The distance between B is adjusted. Therefore, since the first and second slits 5A and 5B do not contact the filtrate hole 1A at the same time, clogging of the filter cloth can be efficiently prevented with a small amount of gas-liquid mixed fluid.

When the spray fine particles of the liquid constituting the first gas-liquid mixed fluid are ejected from the first slit 5A together with the blow gas, they pass through the filtrate hole 1A of the rotary drum 1 very quickly and fill the space 12 of the filter bridge 11. Then, after passing through the small hole of the filter bridge 11, the filter cloth 14
, The liquid spray particles and the blow gas can cause the cake layer adhering to the filter cloth 14 to be peeled off from the rotary drum 1, and play a role in preventing the filter cloth 14 from being clogged. Further, the second gas-liquid mixed fluid is also ejected from the second slit 5B similarly to the first gas-liquid mixed fluid, and passes through the filtrate hole 1A of the rotary drum 1, the space 12 of the filter bridge 11, and the small hole of the filter bridge 11. To reach the filter cloth 14. At this time, even if the residue of the cake layer partially enters the eyes of the filter cloth 14 due to high-speed spraying by the cleaning liquid spray 13 and causes clogging, the second gas-liquid mixed fluid that has passed through the small holes of the filter bridge 11 is removed. The liquid adheres to the filter cloth 14 and instantaneously seals the opening portion without clogging. The gas pressure is increased by confining the blow gas with the filter cloth. The contaminants of the cloth 14 are ejected to the outside, the contaminants of the filter cloth 14 are reliably removed, the clogging of the filter cloth 14 can be prevented, and the filtering ability of the filter cloth 14 can be increased.

Next, an embodiment of the filtration method of the present invention using the rotary single-chamber filter will be described. The steps from filtering the undiluted solution slurry F to washing the cake layer from the outside of the rotary drum 1 are the same as those in the related art, so that the description thereof will be omitted, and the description will be started from the step of peeling the cake layer. When the blow gas is supplied into the center pipe 2 and a liquid such as acetic acid is sprayed from the first liquid spraying spray 15 disposed slightly downstream of the blow gas inlet 2B, the blow gas and the liquid spray fine particles are mixed downstream of the blow gas inlet. As a result, it becomes the first gas-liquid mixed fluid. The gas-liquid mixed fluid flows downstream in the center pipe 2 at the flow velocity of the blow gas. At this time, when the rotary drum 1 is rotating counterclockwise as shown in FIG. 1, the first gas-liquid mixed fluid flows through the center pipe 2 and the valve bar 6 so that the first slit 5 of the valve shoe 5
A, squirts from the first slit 5A, fills the space 12 of the filter bridge 11 through the filtrate hole 1A of the rotary drum 1, and passes through the filter cloth 14 from the small hole of the filter bridge 11 to the cake layer. Spout toward. At this time the first
The cake layer is separated from the filter cloth 14 by the spray fine particles of the gas-liquid mixed fluid and the blow gas, and the cake C is discharged out of the machine via the chute 10.

Subsequently, when the part where the cake layer has been peeled reaches the part facing the cleaning liquid spray 13, the filter cloth 14 is washed with the jet liquid from the cleaning liquid spray 13 and the residue on the surface of the filter cloth 14 is cleaned. Remove. Next, when the cleaned portion reaches the second slit 5B of the valve shoe 5, the second gas-liquid mixed fluid is ejected from the second slit 5B. That is, the blow gas is supplied into the cleaning conduit 8, and the liquid is sprayed from the nozzle 16A of the second liquid spray spray 16 and mixed into the blow gas to become the second gas-liquid mixed fluid. The second gas-liquid mixed fluid reaches the second slit 5B from the washing conduit 8 via the header pipe 8A and the flexible tube 7 in the rotary drum 1 at the flow rate of the blow gas. At this time, when the cleaned portion of the rotating drum 1 reaches the second slit 5B, the second gas-liquid mixed fluid from the second slit 5B is ejected from the second slit 5B, and the rotating drum 1
Of the filter bridge 11 through the filtrate hole 1A
2 and the filter cloth 1
Reach 4 At this time, even if the opening portion and the clogged portion without clogging are mixed in the filter cloth 14, the spray fine particles of the liquid of the second gas-liquid mixed fluid that has passed through the small holes of the filter bridge 11 adhere to the filter cloth 14. In this way, the opening portion without clogging is instantaneously sealed to increase the gas pressure of the blow gas, and the gas pressure acts evenly on the clogged portion. At this gas pressure, the liquid is discharged to the outside together with the impurities in the filter cloth 14. By spouting out, impurities in the filter cloth 14 can be reliably removed, clogging of the filter cloth 14 can be prevented, and a decrease in the filtering ability of the filter cloth 14 can be prevented. Thereafter, when this portion reaches the stock solution vat 3, the stock solution slurry F can be efficiently filtered because the filter cloth 14 is hardly clogged. Therefore, even if the rotary drum 1 rotates and the stock solution slurry F is repeatedly filtered, the filtration capacity does not decrease so much, and the filter can be continuously operated for a long time.

In the above embodiment, the cleaning liquid spray 13 is provided between the first slit 5A and the second slit 5B of the valve shoe 5, but the cleaning liquid spray 13 may not be provided. Further, the blow gas of the first slit 5A and the blow gas of the second slit 5B may be the same gas supply source or different gas supply sources. In addition, the first and second liquid spray sprays 15, 16
The liquid to be sprayed from may be the same or different.

[0023]

According to the first and second aspects of the present invention, in any case, clogging of the filter cloth after peeling the cake layer is reliably prevented, and the filter cloth can be used for a long time. It is possible to provide a rotary single-chamber filter and a filtration method capable of maintaining high filtration efficiency throughout.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part showing an embodiment of a rotary single-chamber filter according to the present invention.

FIG. 2 is a front view showing a mechanism for preparing first and second gas-liquid mixed fluids shown in FIG.

FIG. 3 is a plan view taken along line III-III in FIG. 2;

FIG. 4 is a cross-sectional view orthogonal to the axial direction showing an example of a conventional rotary single-chamber filter.

[Explanation of symbols]

Reference Signs List 1 rotating drum 2 center pipe 3 stock solution vat 4 filtrate tube 5 valve shoe 5A first slit 5B second slit 8 washing conduit (piping) 11 filter bridge 14 filter cloth 15, 16 first, second liquid spray spray (first, second spray) Second
Liquid spraying means)

Claims (2)

[Claims] 1. A rotary drum having a filter cloth stretched on its outer peripheral surface via a filter bridge is mounted on a center pipe, and the lower part of the rotary drum is immersed in a stock vat to suck and filter the stock slurry, and the filtrate is removed from the center pipe. The filtrate is drawn out of the machine by a filtrate pipe connected to the center pipe, and is filtered by a first gas blown from a first slit at an upper portion of a valve shoe connected to the center pipe and having a small gap between the center pipe and the inner peripheral surface of the rotary drum. A rotary single-chamber filter in which a cake layer formed on the outer surface of the cloth is peeled and collected, and impurities in the filter cloth are removed by a second gas blown from a second slit below the valve shoe. A first liquid spraying means for spraying a first liquid is mounted on the center pipe for supplying the first gas, and a second liquid is supplied to a pipe for supplying the second gas. A rotary single-chamber filter equipped with a second liquid spraying means for spraying water. 2. A stock drum in a stock vat is filtered while rotating a rotary drum having a filter cloth stretched on an outer peripheral surface thereof around a center pipe via a filter bridge, and the filtrate is led out of the machine through the center pipe. on the other hand,
The first gas is blown from the first slit at the upper portion of the valve shoe, which communicates with the inner peripheral surface of the rotary drum and has a small gap with the inner peripheral surface of the rotary drum, and the cake layer on the outer surface of the filter cloth is peeled and collected. In a filtration method using a rotary single-chamber filter for removing impurities from a filter cloth by blowing a second gas from a slit, a first liquid is sprayed on the first gas to form a first gas-liquid mixed fluid. After adjusting, this first
While the gas-liquid mixed fluid is blown from the first slit to peel the cake layer, the second gas is sprayed with the second liquid to adjust the second gas-liquid mixed fluid, and then the second gas-liquid mixed A filtering method, characterized in that a fluid is blown from the second slit to wash the filter cloth.