JP2011098262A - Pressure dehydrator and pressure dehydration method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure dehydrator designed for device miniaturization and low power consumption, as well as a pressure dehydration method. <P>SOLUTION: This pressure dehydrator operates as follows: first, a stock solution which is intended for filtration, is forced into a filtration chamber 134 formed between a plurality of juxtaposed filter plates 130 and filter plates 132 with a diaphragm and then, dehydrated. Thereafter, a filter press 1 takes over to perform the job, that is, to inflate the diaphragm 131 installed on one side of the filtration chamber 134 by giving a compression pressure to the diaphragm 131, and thereby, dehydrate a dehydration cake remaining in the filtration chamber 134 by compression. In addition, the pressure dehydrator is equipped with a pump 2 which supplies water to the diaphragm 131, a compression tank 3 which applies a compression pressure to the diaphragm 131 by pressurizing the water supplied to the diaphragm 131 by a pump 2 and an air compressor 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pressure dehydration apparatus and a pressure dehydration method in which a dehydrated cake is squeezed and dehydrated by a pressurized diaphragm to filter and dehydrate the stock solution.

  Conventionally, in a filter press in which sludge or the like is pressed and dehydrated into a filtration chamber formed between a plurality of parallel filter plates, the dehydrated cake is squeezed and dehydrated with a diaphragm provided on one side of the filtration chamber. It expanded with compressed water or compressed air, and the volume of the filtration chamber into which undiluted liquids, such as sludge, were injected by this expansion was narrowed. At this time, a high pressure of about 1.5 to 2.0 MPa was applied to the diaphragm for about 20 to 60 minutes.

  Thus, in the filter press which squeezes and dehydrates using a diaphragm, there exists a thing which supplies compressed air as a pressing pressure given to a diaphragm in a small thing. On the other hand, in the medium to large size, the compression pressure applied to the diaphragm is higher than that of the small size, so the safety of the compressed fluid air and the size of the air compressor that supplies the compressed air are increased. In addition, compressed water was employed instead of compressed air.

For example, in the filter press described in Patent Document 1 shown below, compressed air of about ³ to 5 kg / cm ² (0.3 to 0.5 MPa) is injected into the diaphragm, and then 10 to 20 kg / cm ² ( A technique for compressing cake by injecting compressed water of about 1 to 2 MPa) is employed. In such a technique, since the squeezing pressure at the time of injecting the squeezed water into the diaphragm is high, a large-capacity squeeze pump is required, and the apparatus has been enlarged. Moreover, much power consumption is consumed by using a large capacity squeezing pump.

  On the other hand, in the filter press described in Patent Document 2 shown below, air or water pressure fluid is injected into the diaphragm in advance before injecting the stock solution into the filtration chamber, and then the stock solution is injected into the filtration chamber and then into the diaphragm. Furthermore, a technique for injecting high-pressure fluid with a pump is employed. Even in such a technique, since a pressurized fluid such as high-pressure air or water is supplied to the diaphragm by a pump, a large-capacity squeeze pump is required as described above, and the apparatus has been enlarged. Moreover, much power consumption is consumed by using a large capacity squeezing pump.

  Moreover, in the filter press described in the patent document 3 shown below, pressurized air is employ | adopted as the pressing pressure given to a diaphragm. In such a technique, as described above, since air is a compressive fluid, the pressure of pressurized air is set to a relatively low pressure in consideration of safety. For this reason, it was applicable only to a relatively small filter press that performs the pressing process in a short time. On the other hand, when a low pressure compressed air is supplied to the diaphragm with a relatively large filter press that requires a long time pressing process, a large amount of time is required for the pressing process. Further, when the pressurized air is increased in pressure, a large amount of power is consumed in addition to an increase in the size of the air compressor that supplies the pressurized air.

Japanese Patent Publication No.2-12122 JP-A-61-82815 JP 2001-54704 A

  As described above, in a conventional filter press employing a diaphragm, a gas or liquid pressure fluid is used as a squeezing pressure for expanding the diaphragm, and this pressure fluid is directly pressurized to a predetermined pressure by a pump to form a diaphragm. I was supplying.

  For this reason, in order to obtain a high pressing pressure to be supplied to the diaphragm in a short time, a large pump is required, which leads to an increase in the size of the apparatus. Furthermore, the problem that power consumption increases by the enlargement of a pump will also be caused.

  Accordingly, the present invention has been made in view of the above, and an object of the present invention is to provide a pressure dehydration apparatus and a pressure dehydration method that achieve downsizing and low power consumption of the apparatus. .

  In order to achieve the above object, the invention according to claim 1 is provided on one side of the filtration chamber after the stock solution to be filtered is pressed into the filtration chamber formed between the filter plates arranged in parallel and dehydrated. In a pressure dehydration apparatus equipped with a filter press that applies a pressure to the diaphragm and expands the diaphragm to squeeze and dehydrate the dewatered cake remaining in the filtration chamber, a pump that supplies liquid to the diaphragm, and a pump that supplies the diaphragm to the diaphragm It is characterized by having a pressing pressure supply means for pressurizing the liquid with a pressure gas and applying a pressing pressure to the diaphragm.

  The invention according to claim 2 is the invention according to claim 1, wherein the pressing pressure supply means stores the equivalent liquid when supplied to the diaphragm, and the pressure of the gas in the pressing tank by the pressure gas. Selectively pressurize the liquid supplied to the diaphragm by selectively controlling the communication between the gas compressor that pressurizes the stored liquid by increasing the pressure, the squeezing tank and the diaphragm, and pressurizing the liquid in the compression tank And a control valve for controlling.

  The invention described in claim 3 is characterized in that, in the invention described in claim 2, the squeezing tank is supplied with a liquid from a water receiving tank for storing the liquid supplied to the diaphragm by the pump and stored. To do.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the liquid is water and the pressure gas is air.

  In the invention according to claim 5, after the stock solution to be filtered is pressed into a filtration chamber formed between a plurality of parallel filter plates and dehydrated, a compression pressure is applied to a diaphragm provided on one side of the filtration chamber. In the pressurized dehydration method in which the diaphragm is expanded and the dewatered cake remaining in the filtration chamber is squeezed and dehydrated, after the liquid is supplied to the diaphragm, the liquid supplied to the diaphragm is pressurized by the pressure gas and then pressurized by the pressure gas. The pressure is applied to the diaphragm by the pressurized liquid.

  According to the present invention, the liquid supplied to the diaphragm is pressurized with the compressed gas, so that the compression pressure is applied to the diaphragm. Therefore, it is possible to reduce the power consumption when the compression pressure is applied to the diaphragm. In addition, the configuration can be reduced in size.

It is a figure which shows the structure of the pressure dehydration apparatus which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the structure of a dehydration unit. It is process drawing which shows the closing board process and press-fit process in a dehydration process. It is process drawing which shows the pressing process in a dehydration process, and an open plate process. It is process drawing which shows the cake peeling process and filter cloth washing | cleaning process in a spin-drying | dehydration process.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a configuration of a pressure dehydration apparatus according to a first embodiment of the present invention. The pressure dehydrating apparatus shown in FIG. 1 includes a filter press 1 that functions as a dehydrator for dehydrating a stock solution, a pump 2, a squeezing tank 3, and an air compressor (air compressor) 4.

  In the filter press 1, a plurality of dewatering units 13 are arranged in parallel in a horizontal direction on a guide rail 12 supported by a front frame 10 and a rear frame 11. The plurality of dewatering units 13 are movably supported on the guide rail 12 and are fastened by a pressing member 15 that reciprocates along the guide rail 12 by the driving force of, for example, an electric cylinder 14 or a hydraulic cylinder. As such a filter press 1, conventionally known, for example, those described in Japanese Patent Application Laid-Open Nos. 2001-104714 and 2004-174304 are known.

  The dehydration unit 13 is configured, for example, as shown in the perspective view of FIG. In FIG. 2, the dehydrating unit 13 is arranged such that a filter plate 130 and a diaphragm-attached filter plate 132 provided with a diaphragm 131 are opposed to each other, and the filter plate 130 and the diaphragm-attached filter plate 132 are filtered to the opposite side. A chamber 134 is formed. Each filter cloth 133 is disposed on the filter plate 130 inside the filtration chamber 134 and the filter plate 132 with the diaphragm, and between the filter plate 130 and the filter cloth 133 and between the filter plate 132 with the diaphragm and the filter cloth 133. A filter bed 135 is formed.

  A stock solution supply path 136 for injecting a stock solution such as slurry to be dehydrated into the filtration chamber 134 is provided in the upper part of the filtration chamber 134. The diaphragm-attached filter plate 132 is formed with a compressed water injection passage 137 that penetrates the diaphragm-attached filter plate 132 and reaches the diaphragm 131. At the lower part of the filter plate 130 and the diaphragm-attached filter plate 132, a filtrate discharge path 138 is provided which communicates with the filter bed 135 and discharges the filtrate exuded from the filtration chamber 134 through the filter cloth 133 to the outside. Yes. As such a dehydration unit, a conventionally known one, for example, one described in JP-A No. 2002-292221 is known.

  Returning to FIG. 1, the pump 2 uses the diaphragm 131 to store the water stored in the water receiving tank 6 through the compressed water supply path 5 a communicated with the compressed water injection path 137 formed in the diaphragm-attached filter plate 132 of the dehydration unit 13. To supply. The pump 2 supplies the water stored in the water receiving tank 6 to the compressed tank 3 through the compressed water supply path 5b.

  A check valve 7 for preventing the backflow of the compressed water from the dewatering unit 13 side and the squeezing tank 3 side to the pump 2 side is provided in the compressed water supply path 5 a that connects the pump 2 and the compressed water injection path 137 of the dehydrating unit 13. The 1st valve V1 and the 2nd valve V2 which control opening and closing of the flow path of compressed water are provided.

  The squeezing tank 3 stores squeezed water that applies a squeezing pressure to the diaphragm 131. The stored compressed water is supplied by the pump 2 from the water receiving tank 6 through the compressed water supply path 5a and the compressed water supply path 5b. The compressed water supply path 5b is provided with a third valve V3 that communicates the compressed water supply path 5a between the first valve V1 and the second valve V2 and the compressed tank 3, and controls the opening and closing of the flow path of the compressed water. ing. The compressed tank 3 is supplied with compressed air having a pressure of about 1 to 2 MPa, for example, about 1.5 MPa. The water stored in the compression tank 3 is pressurized by this compressed air. The squeezing tank 3 is composed of, for example, a second type pressure vessel made of a steel plate cylindrical rod capable of withstanding the pressure of about 2 MPa. The pressure tank 3 is connected to a fourth valve V4 that controls the pressure in the pressure tank 3 to open to the atmosphere.

  The air compressor 4 is connected to the squeezing tank 3 to supply high-pressure squeezed air to the squeezing tank 3, squeezes the water stored in the squeezing tank 3, and generates compressed water that pressurizes the diaphragm 131. Between the air compressor 4 and the compression tank 3, the 5th valve V5 which controls opening and closing of the flow path of compressed air is provided. The first valve V <b> 1 to the fifth valve V <b> 5 are configured by control valves that are controlled to open and close by air or electrically based on an open / close command from the outside.

  Next, with reference to the dehydration process diagrams in the filter press 1 of FIGS.

  First, in the closing plate step (FIG. 3A) to be performed first, the electric cylinder 14 is driven to move the pressing member 15 to the front frame 10 side, and the filter plate 130 and the diaphragm-attached filter plate of each of the dehydrating units 13. 132 is tightened to form a filtration chamber 134.

  In the next press-fitting step (FIG. 3B), a stock solution such as slurry to be dehydrated is press-fitted into the filtration chamber 134 through the stock solution supply path 136. Moisture of the stock solution press-fitted into the filtration chamber 134 oozes out through the filter cloth 133 into the filter plate 130 and the filter bed 135 on the diaphragm-attached filter plate 132 side, and is discharged from the filtrate discharge passage 138 to the outside. As a result, the stock solution press-fitted into the filtration chamber 134 is filtered, and the solid components in the stock solution remain in the filtration chamber 134 as a dehydrated cake, while the water in the stock solution is taken out as a filtrate.

  In the subsequent pressing step (FIG. 4A), first, the first valve V1 is opened, the second valve V2 is closed, the third valve V3 is opened, the fourth valve V4 is opened, After the valve V5 is controlled to be closed, the pump 2 is driven. Thereby, the stored water stored in the water receiving tank 6 is supplied to the squeezing tank 3, the squeezed water is stored in the squeezing tank 3, and the drive of the pump 2 after storage is stopped. In addition, you may implement this storage process previously before this pressing process.

  Subsequently, after controlling the second valve V2 from the closed state to the open state, the third valve V3 from the open state to the closed state, the fourth valve V4 from the open state to the closed state, and the fifth valve V5 from the closed state to the open state. The pump 2 is driven to supply and fill the water stored in the water receiving tank 6 into the diaphragm 131 of each dehydration unit 13. At this time, it is not necessary to press-fit the water stored in the water receiving tank 6 into the diaphragm 131, and it is only necessary to apply pressure to the water so that water is supplied and filled. For this reason, the drive capability of the pump 2 can be configured to be much smaller than that when the compressed water of 1 MPa or more is pressed into the diaphragm 131. Furthermore, simultaneously with the supply of water to the diaphragm 131, the air compressor 4 is driven to pressurize the air in the squeezing tank 3 to increase the pressure in the squeezing tank.

  Subsequently, the drive of the pump 2 is stopped, the first valve V1 is controlled from the open state to the closed state, and the third valve V3 is controlled from the closed state to the open state, and then stored in the squeezing tank 3 and continuously driven. Pressure is applied to the water filled in the diaphragm 131 with the compressed water compressed by the compressed air generated by the compressor 4. At this time, the pressure of the compressed water is set to, for example, about 1.5 MPa between 1 and 2 MPa. Therefore, the diaphragm 131 is pressurized with high-pressure compressed water in the compression tank 3. As a result, the pressurized diaphragm 131 expands to reduce the volume of the filtration chamber 134, and the dehydrated cake remaining in the filtration chamber 134 after the press-fitting step is further squeezed and dehydrated, increasing the solid content concentration of the dehydrated cake. A dehydrated cake with a very low moisture content is produced. In this way, after the moisture of the dewatered cake has become extremely small, the driving of the air compressor 4 is stopped, the second valve V2 is closed from the open state, the third valve V3 is closed from the open state, After controlling the 4 valve V4 from the closed state to the open state and the fifth valve V5 from the open state to the closed state, the pressure in the squeezing tank 3 is released to the atmosphere, and the squeezing process is completed.

  In the next plate opening process (FIG. 4B), the electric cylinder 14 is driven, the pressing member 15 is moved to the rear frame 11 side, and the tightening of all the dehydrating units 13 is released. As a result, the filter plates 130 and the diaphragm-attached filter plates 132 of all the dehydration units 13 are opened.

  In the subsequent cake peeling step (FIG. 5 (a)), when the filter plates 130 of all the dehydration units 13 and the diaphragm-attached filter plates 132 are opened apart by a predetermined distance, the dehydrated cake 30 is held. The filter cloth 133 of all the dewatering units 13 starts to travel downward at the same time, while the dewatered cake is peeled off from the filter cloth 133.

  In the last filter cloth cleaning step (FIG. 5B), when the dehydrated cake is peeled off from the filter cloth 133, the filter cloth 133 starts traveling all at once and returns to the original position again. In the middle of the return, washing water supplied from a washing water pipe 31 provided below the dehydrating unit 13 is jetted by a filter cloth washing pump (not shown) to wash the filter cloth 133, and the filter cloth 133 Prevent clogging. Thereby, the above-described series of dehydration steps is completed.

  As described above, in the above embodiment, when the diaphragm 131 is expanded and the stock solution is squeezed and dehydrated, water is first supplied and injected into the diaphragm 131, and then the supplied and injected water is pressurized with compressed air. For this reason, when water is supplied and injected into the diaphragm 131, the pressure applied to the water may be a pressure at which water is supplied to the diaphragm 131. Therefore, the pump 2 that supplies water to the diaphragm 131 ensures a high pressure for a long time. It doesn't need the driving ability. Therefore, the capacity | capacitance of the pump 2 can be made remarkably small compared with the prior art which supplies compressed water to a diaphragm with a pump, and it becomes possible to reduce a structure. In addition, it is not necessary to continue to drive the pump 2 for a long time during the squeezing process, and it is only necessary to drive the diaphragm 131 for a short time during which water reaches the diaphragm 131, so that the power consumption of the pump 2 can be reduced. It becomes.

  In addition, since the electric power at the time of driving | running the air compressor 4 is needed by providing the air compressor 4 compared with the past, since the air compressor 4 only needs to pressurize the air in the compression tank 3, In a pressure dehydration apparatus that requires a pump 2 with a power consumption of, for example, about 11 kW, the power consumption of the air compressor 4 is, for example, about 3.7 kW, which is significantly less than the power consumption of the pump 2. That's it. Therefore, in the compression processing step, after supplying water to the diaphragm 131, the driving of the pump 2 is stopped, and the air compressor 4 is driven instead of driving the pump 2, thereby driving the pump during the pressing process. Compared to the above, the power consumption can be reduced by about 75%, so that the power consumption can be reduced and energy saving can be achieved. In particular, the reduction effect is large for a large pressure dehydrating apparatus that requires a long pressing time.

  Moreover, since the inside of the diaphragm 131 is filled with water compared with the case where the diaphragm 131 is directly pressurized with compressed air, danger is avoided by the high-pressure compressed air. Furthermore, since the pressure of the compressed air given to the compressed tank 3 is set to 5 MPa or less, it is not subject to the legal regulations of the High Pressure Gas Safety Law established for compressed air of 5 MPa or more. (Specification) can be simplified.

  Further, since the pump 2 does not require a large capacity as described above, the pump 2 has a smaller configuration than the filter cloth cleaning pump that supplies cleaning water for cleaning the filter cloth 133, and can also be used as a filter cloth cleaning pump. It becomes possible. Thereby, in addition to being able to reduce the size of the apparatus, it is possible to reduce equipment costs.

  The present embodiment describes a filter press of a filter cloth traveling type, but it can also be applied to a filter press of a filter cloth fixed type.

DESCRIPTION OF SYMBOLS 1 ... Filter press 2 ... Pump 3 ... Pressure tank 4 ... Air compressor 5a, 5b ... Pressurized water supply path 6 ... Water receiving tank 7 ... Check valve 10 ... Front frame 11 ... Rear frame 12 ... Guide rail 13 ... Dehydration unit 14 ... Electric cylinder 15 ... Pressing member 30 ... Dehydrated cake 31 ... Washing water tube 130 ... Filter plate 131 ... Diaphragm 132 ... Diaphragm filter plate 133 ... Filter cloth 134 ... Filtration chamber 135 ... Filtration bed 136 ... Undiluted solution supply path 137 ... Pressure water injection Path 138 ... Filtrate discharge path V1 ... First valve V2 ... Second valve V3 ... Third valve V4 ... Fourth valve V5 ... Fifth valve

Claims (5)

After the stock solution to be filtered is pressed into a filtration chamber formed between a plurality of parallel filter plates and dehydrated, the diaphragm is expanded by applying a squeezing pressure to a diaphragm provided on one side of the filtration chamber. In a pressure dewatering device equipped with a filter press for squeezing and dewatering the dewatered cake remaining in the chamber,
A pump for supplying liquid to the diaphragm;
A pressure dehydrating apparatus comprising: a pressure supply means for applying pressure to the diaphragm by pressurizing the liquid supplied to the diaphragm by the pump with a pressure gas. The pressing pressure supply means is
A squeeze tank that stores liquid equivalent to that supplied to the diaphragm;
A gas compressor that pressurizes the stored liquid by increasing the pressure of the gas in the squeezing tank with pressure gas; and
A control valve that selectively controls the communication between the squeezing tank and the diaphragm and selectively pressurizes the liquid supplied to the diaphragm by pressurizing the liquid in the squeezing tank. The pressure dehydration apparatus according to claim 1. The pressure dehydration apparatus according to claim 2, wherein the squeezing tank is supplied with the liquid from the water receiving tank storing the liquid supplied to the diaphragm by the pump and stored. The pressure dehydration apparatus according to any one of claims 1 to 3, wherein the liquid is water and the pressure gas is air. After the stock solution to be filtered is pressed into a filtration chamber formed between a plurality of parallel filter plates and dehydrated, the diaphragm is expanded by applying a squeezing pressure to a diaphragm provided on one side of the filtration chamber. In the pressure dehydration method of pressing and dewatering the dewatered cake remaining in the chamber,
A pressure dehydration method comprising: supplying a liquid to the diaphragm, pressurizing the liquid supplied to the diaphragm with a pressurized gas, and applying a pressing pressure to the diaphragm with the pressurized liquid pressurized with the pressurized gas .

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