JP2004082036A - Heating type filter press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heating type filter press enhancing the thermal efficiency and the peeling-off property of cake by bringing a heating plate made of metal into directly contact with the cake and simultaneously using vacuum suction. <P>SOLUTION: In the heating type filter press, wedge wires (2, 4) are stretched over the heating plate (1) formed to a flat plate shape and a filtering surface of a filter plate (3) and are brought into directly contact with the cake in a filter chamber (5). Vacuum suction holes (1e, 3e) communicated with the filter chamber (5) are arranged on the heating plate (1) or the filter plate (3). The wedge wire (2) subjected to heat conduction from the heating plate (1) is directly contacted with the cake and reduces viscosity and resistivity of a concentrated sludge and the cake to improve a dehydration property. A pressure of the filter chamber (5) is reduced by the vacuum suction, a boiling point is lowered and a moisture content in the cake is further made less. Deterioration of the filter medium does not occur even if the wedge wire (2) is heated and deterioration of the filtering characteristic does not occur even if the filter medium is not washed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a filter press suitable for the treatment of tap water sludge, sewage sludge, industrial wastewater sludge, etc., and in particular, improves the dewatering property by heating concentrated sludge or cake in a filtration chamber of the filter press, and combines vacuum suction. To reduce the water content of the dewatered cake.
[0002]
[Prior art]
Conventionally, filter presses that can be subjected to filter pressurization are more advantageous for non-compressible cakes and are often employed as solid-liquid separation devices. Further, a filter press using a diaphragm filter plate can be used even for cake having compressibility and poor filterability. A filter cloth is used as a filter medium for these filter presses. The filter medium needs to have strength enough to withstand pressure and squeezing pressure, and a thick filter cloth of 1.0 to 2.0 mm is used. Then, a filtration chamber is formed by alternately arranging the diaphragm filter plate and the metal heating filter plate, and a pair of filter cloths is suspended in the filtration chamber provided with the negative pressure means, thereby heating the cake in the filtration chamber. A device that reduces the water content of the dewatered cake by suction to shorten the dewatering and pressing time is also known, as described in, for example, JP-A-2000-334221.
[0003]
[Problems to be solved by the invention]
Even if the filter cloth is washed every time the cake is discharged, the filter cloth used for the filter press repeatedly adheres fine particles and precipitates crystals to the eyes of the filter cloth. Use became impossible, and it was necessary to replace the filter cloth in two to six months. The conventional filter press that heats the dewatered cake during the dewatering process can improve the processing capacity and decrease the water content.However, a filter cloth is interposed between the cake and the metal heating plate. As a result, the efficiency of heat conduction from the heating plate to the cake became poor, and drying took time. Further, since the resinous filter cloth is weak to heat and is pressed by the diaphragm filter plate, the fold of the filter cloth is crushed, and the performance is deteriorated and deteriorated at an early stage. Further, since both sides of the cake are in contact with the filter cloth, there is a disadvantage that the peelability of the cake is poor. The present invention improves on the conventional disadvantages by making good use of a metal filter medium.A metal heating plate is brought into direct contact with the cake without the use of a filter cloth, and the vacuum efficiency is used in combination with the heat efficiency and the cake. An object of the present invention is to provide a heated filter press having improved peelability.
[0004]
[Means for Solving the Problems]
The gist of the present invention is a filter press in which a heating plate and a filter plate on which a metal filter medium is stretched are alternately arranged in parallel to form a filtration chamber, and the heating plate and the filtration plate are opened to discharge a dried cake generated in the filtration chamber. A wedge wire is stretched on the filtration surface of the heating plate and filter plate formed in a flat plate, and is directly in contact with the cake in the filtration chamber, and the heating plate or the filtration plate is provided with a vacuum suction hole communicating with the filtration chamber. The heating plate directly contacts the concentrated sludge or cake and changes the properties of the organic matter in the sludge. In particular, the viscosity and specific resistance of the cake close to the wedge wire, which has the lowest water content and poor water permeability, are reduced. Since both sides of the heating plate are used, the heat efficiency is high, and the decompression in the filtration chamber lowers the boiling point and improves the dehydration with a small amount of heat. It is more efficient in terms of heating speed and temperature than heating through a filter cloth.
[0005]
The wedge wire stretched on the filtration plate of the heating plate and the filter plate may be used as a punching metal, and since the filter medium is a metal, heat conduction is good, drying is quick, and processing can be performed in a short time. The wedge wire and the punched metal do not deteriorate the filter medium even when heated, and do not deteriorate in filtration characteristics even without washing the filter medium. The heating means for the cake in the filtration chamber is one in which a plurality of heating pipes are arranged inside the filtration bed of the heating plate. The heating plate may be provided with a heating fluid supply hole on a heating plate on which a wedge wire is stretched, and the heating supply hole may be communicated with a filtration bed of a filter plate.
[0006]
Then, instead of a filter plate with a wedge wire stretched, a diaphragm filter plate with a diaphragm stretched on a core plate, the surface of the diaphragm is formed in a planar shape, formed into a flat shape, and directly contacted with the cake Since the diaphragm filter plate uses water for squeezing, there is no deterioration due to heat, and high-pressure squeezing of the cake in the filtration chamber becomes possible.
In addition, the diaphragm filter plate may be a diaphragm filter plate having a diaphragm having a filtrate groove, and a filter cloth may be hung on the filtration bed, and the filtrate is discharged from both sides of the cake in the filtration chamber and compressed. Thereby, the cake is plastically deformed and easily peeled from the filter cloth. The heating surface of the cake on the heating plate side is powdered so that the cake can be easily peeled off. The filter cloth hung on the filtration surface of the diaphragm filter plate is not deteriorated by being cooled by the compressed water of the diaphragm filter plate.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The apparatus according to the present invention is configured as described above. When sludge is press-fitted into a filtration chamber formed by a heating plate and a filter plate with a wedge wire stretched, the sludge is filled in the filtration chamber while being concentrated. When steam or hot air is supplied to the heating plate to heat the concentrated sludge, the heating plate on which the wedge wire is stretched comes in direct contact with the cake, drying is performed quickly, and the properties of the organic matter in the sludge change, causing the concentrated sludge to change. The viscosity and the specific resistance are reduced, and the dehydration property is improved. Vacuum suction reduces the pressure in the filtration chamber, lowering the boiling point, evaporating water and further reducing the water content in the cake. The cake surface of the dewatered cake in the filtration chamber becomes powdery on the heating surface, and is easily peeled off from the heating plate. It is possible to shorten the dewatering time and obtain a cake having a low water content. In addition, even if a wedge wire is used as a punching metal, the wedge wire directly contacts the cake in the filtration chamber and has good heat transfer efficiency.
[0008]
If the filter plate facing the heating plate is a diaphragm filter plate, the cake is squeezed by the diaphragm and the water content of the cake is further reduced. Then, the squeezed cake surface is plastically deformed and easily peeled from the diaphragm. A filter cloth may be hung on the filtration surface of the diaphragm filter plate, the filtrate is discharged from both sides of the cake in the filtration chamber, and the cake is separated from the filter cloth by squeezing. Then, when the filter plate and the heating plate are opened, the heating surface of the cake on the heating plate side is powdered and the cake is easily peeled off from the wedge wire or the punching metal, and the cake is discharged out of the filtration chamber by its own weight. It is possible to shorten the pressing time and obtain a cake having a low water content.
[0009]
【Example】
The filter press according to the present invention will be described in detail with reference to the drawings. First, FIG. 1 is a longitudinal sectional view of a heating plate and a filter plate with a wedge wire stretched, and a filtration plate 1a having a filtrate discharge groove in the heating plate 1. Is formed, and a wedge wire 2 is stretched on the filtration bed 1a. The filtration surface of the wedge wire 2 stretched on the heating plate 1 and the thickness of the sealing portion 1b at the peripheral portion are formed in a flat plate shape. The filter plate 3 opposed to the heating plate 1 is provided with a filter bed 3a formed in a concave shape inside and having a filtrate discharge groove, and a frame-shaped seal portion 3b on the peripheral surface. A wedge wire 4 is also stretched on the filter bed 3a of the filter plate 3.
[0010]
The expanded wedge-shaped ends of the wedge wires 2 and 4 stretched over the heating plate 1 and the filter plate 3 are attached to the filtration beds 1a and 3a, and the slits 2a and 4a sides of the wedge wires 2 and 4 are filtered. There is. Although the wedge wire shown in FIG. 1 is conceptually described, FIG. 2 is a plan view of the heating plate, and the wedge wires 2 and 4 stretched on the heating plate 1 and the filter plate 3 have slits 2a and 4a thereof. Are arranged vertically. A large number of the heating plates 1 and the filter plates 3 are arranged in parallel, and when the heating plate 1 and the filter plates 3 are closed, the filtration chamber 5 is formed by the front and rear heating plates 1 and the filter plates 3. Since the wedge wires 2 and 4 are expanded in a wedge shape toward the back surface, the filtrate is easily separated. Since the filtration grooves for discharging the filtrate are provided in the filtration beds 1a and 3a of the heating plate 1 and the filter plate 3, the separated filtrate is discharged quickly, and the time for solid-liquid separation of sludge is reduced. The wedge wires 2 and 4 stretched over the heating plate 1 and the filter plate 3 may be punched metal. Since the filter material is metal, heat conduction is good, drying is quick, and processing can be performed in a short time.
[0011]
Stock solution supply passages 1c, 3c are provided in the upper seal portions 1b, 3b of the heating plate 1 and the filter plate 3, and are connected to the front surface of the wedge wire 4 through the liquid supply holes 3d of the filter plate 3, so that the heating plate 1 The stock solution is supplied to the filtration chamber 5 between the plates 3. Further, a vacuum suction hole 3e communicating with a filtration bed 3a of the filter plate 3 is provided in a seal portion 3b below the filter plate 3, and is connected to a known vacuum source (not shown). The filtration chamber 5 is evacuated from the back surface of the wedge wire 4 to depressurize the filtration chamber 5 and discharge the filtrate. The sealing portion 1b at the lower portion of the heating plate 1 is also provided with a filtrate discharge hole 1d communicating with the filtration bed 1a on the back surface of the wedge wire 2, and the filtrate subjected to solid-liquid separation with the wedge wire 2 is filtrated with a filtrate discharge hole 1d. Also discharged from The vacuum suction hole 3e provided in the filter plate 3 may be replaced with the filtrate discharge hole 1d of the heating plate 1.
[0012]
FIG. 3 is a plan view of the heating plate, in which a plurality of heating pipes 6 are arranged inside the heating plate 1, and steam or hot air is supplied from a supply port 6 a provided in the heating plate 1. The filter bed 1a is heated and discharged from the discharge port 6b of the heating plate 1. Heat is transmitted from the heated filter bed 1a to the wedge wire 2 by heat conduction, and the dewatered cake is directly heated. Since both sides of the heating plate 1 are used, the thermal efficiency is high, the properties of the organic matter in the sludge change, the viscosity and specific resistance of the concentrated sludge and cake are reduced, and the dewatering property is improved. The wedge wire 2 heated by heat conduction from the heating plate 1 directly contacts the cake and drying is performed quickly, and the dewatered cake in the filtration chamber 5 is formed by powdering the cake surface of the heating surface and the heating plate 1 From the wedge wire 2 stretched over the wire. At the same time, the pressure in the filtration chamber 5 is reduced by the vacuum suction, so that the boiling point is lowered, and the water content in the cake is evaporated to lower the water content of the cake.
[0013]
FIG. 4 shows another embodiment in which a diaphragm filter plate is used in place of a filter plate, in which heating plates 1 and diaphragm filter plates 7 are alternately arranged side by side, and the diaphragm filter plate 7 has a concave core. A diaphragm 9 having a flat surface 9a is stretched over the plate 8. In the embodiment of the present invention, the filtrate discharge hole 1d of the heating plate 1 in FIG. 1 is connected to a vacuum source as a vacuum suction hole 1e. A feed plate 14 is fixed to the front surface of the stock solution supply passage 7a of the diaphragm filter plate 7, and the stock solution passes from the stock solution supply passage 7a of the diaphragm filter plate 7 to the filtration chamber 5a through the solution supply hole 14a of the stock plate 14. To perform solid-liquid separation. High-pressure water is supplied to the back surface of the diaphragm 9 from a pressure water hole 8b provided in the seal portion 8a of the core plate 8 to squeeze the cake that has undergone solid-liquid separation, and the filtrate flows through the vacuum suction hole 1e of the heating plate 1 Is sucked and discharged. The squeezed cake surface is plastically deformed and easily peeled from the diaphragm 9. Since the diaphragm filter plate 7 uses water for squeezing, there is no deterioration due to heat.
[0014]
FIG. 5 shows another embodiment in which a filter cloth is hung on the front surface of a diaphragm filter plate. A diaphragm filter plate 10 opposed to a heating plate 1 has a filtrate groove in a core plate 11 formed in a concave shape. A diaphragm 12 is stretched, and filter cloths 13, 13 are suspended before and after the diaphragm filter plate 10. A liquid supply plate 14 is fixed to the upper part of the filter cloth 13 and is provided opposite to the undiluted solution supply passages 1 c and 10 a provided in the heating plate 1 and the diaphragm filter plate 10. The undiluted solution passes from the undiluted solution supply passages 1c and 10a through the liquid supply hole 14a of the liquid supply plate 14 and is pressed into the filtration chamber 5b. The seal portion 11a of the core plate 11 is provided with a pressure water hole 11b communicating with the back surface of the diaphragm 12, and a filtrate discharge hole 11c communicating with the filtrate groove of the diaphragm filter plate 10 on the back surface of the filter cloth 13. Also in the embodiment of the present invention, the filtrate discharge hole of the heating plate 1 is connected to a vacuum source as a vacuum suction hole 1e. The contact surface between the cake and the filter cloth 13 is only one surface on the side of the diaphragm filter plate 10 to be squeezed, and the filter cloth 13 is not deteriorated by being cooled by the squeezed water of the diaphragm filter plate 10.
[0015]
FIG. 6 is a longitudinal sectional view of another embodiment of the heating plate. The lower sealing portion 15a of the flat heating plate 15 on which the wedge wire 2 is stretched is provided with a heat supply hole 15b for hot air. The wire 2 is in communication with the filtration bed 15 c of the heating plate 15 on the back side. A filtering chamber 5c is formed by a concave filter plate 3 in which a wedge wire 4 to be attached is stretched on a filtering bed 3a. A vacuum suction hole 3e is provided in a lower seal portion 3b of the filter plate 3, and the wedge wire 2 is directly heated by a heating fluid, and at the same time, hot air is sent into the filtration chamber 5c, and the concentrated sludge and the viscosity of the cake in the filtration chamber 5c are violated. And lower the specific resistance. Then, the filtrate and waste heat are discharged from the vacuum suction holes 3e of the filter plate 3.
[0016]
FIG. 7 shows a dewatering cake peeling device in which a cake peeling device is provided depending on the properties of the undiluted solution. Above the parallel heating plate 1 and filter plate 3, a cylinder 17 supported on a gantry 16 is provided. The front surfaces of the heating plate 1 and the filter plate 3 in which the piston rod 18 of the cylinder 17 is opened can be moved up and down. A pair of scrapers 21, 21 urged by a spring 20 are provided at the tip of a piston rod 18 of the cylinder 17. When the piston rod 18 is extended, the scraper 21 stretches the heating plate 1 and the filter plate 3. The cake is lowered while slidingly contacting the wedge wires 2 and 4, and the cake is separated from the wedge wires 2 and 4. A cleaning pipe 22 is provided at the lower end of a cleaning hose 19 hanging from the gantry 16, and the cleaning water is sprayed on the wedge wires 2 and 4 stretched on the opened heating plate 1 and the filter plate 3. In the apparatus of FIG. 4 in which the diaphragm filter plate 7 is brought into direct contact with the cake, the apparatus may be provided only on the heating plate side.
[0017]
【The invention's effect】
The present invention is configured as described above, and the heating type filter press according to the present invention has a good heat conduction efficiency because the heating plate is brought into direct contact with the cake without the interposition of the filter cloth. Performance can be improved. That is, in the conventional heating type filter press, the filter cloth is interposed between the cake and the heating plate, and the heat conduction efficiency is poor, and the performance of the filter cloth is deteriorated and deteriorated early, and both sides of the cake come into contact with the filter cloth. However, in the present invention, a wedge wire is stretched on the filtration surface of the heating plate and the filter plate formed in a flat plate, and is directly brought into contact with the cake in the filtration chamber, and the heating is performed. Vacuum suction holes communicating with the filtration chamber are provided on the plate or filter plate, and the thermally conductive wedge wire directly contacts the cake, reducing the viscosity and specific resistance of the concentrated sludge and cake and improving dewatering properties Is what is done. In particular, it is possible to reduce the viscosity and specific resistance of the cake close to the wedge wire, which has the lowest water content and poor water permeability. Then, the filtration chamber is depressurized by vacuum suction, the boiling point is lowered, and the water is evaporated, so that the water content in the cake is further reduced. Compared with the conventional apparatus using a filter cloth, the cake is dried faster, and deterioration and clogging of the filter medium can be eliminated.
[0018]
The wedge wire of the filter medium may be a punching metal. Since the filter medium is a metal, heat conduction is good, drying is quick, and processing can be performed in a short time. The wedge wire and the punched metal do not deteriorate the filter medium even when heated, and do not deteriorate in filtration characteristics even without washing the filter medium. Then, the filter plate opposite to the heating plate may be a diaphragm filter plate. Since the diaphragm filter plate uses water for squeezing, there is no deterioration due to heat, and high pressure squeezing of the cake in the filtration chamber becomes possible. Further, a filter cloth may be hung on the filtration surface of the diaphragm filter plate, and the filtrate is discharged from both sides of the cake in the filtration chamber, and the cake is plastically deformed by squeezing, so that the cake is easily separated from the filter cloth. The filter cloth suspended on the filtration surface of the diaphragm filter plate is not deteriorated by being cooled by the compressed water of the diaphragm filter plate.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a heating plate and a filter plate forming a filtration chamber of a heated filter press according to the present invention.
FIG. 2 is a plan view of a heating plate on which a wedge wire is stretched.
FIG. 3 is a plan view of a heating plate provided with a heating pipe.
FIG. 4 is a longitudinal sectional view of another embodiment using a diaphragm filter plate instead of the filter plate.
FIG. 5 is a longitudinal sectional view of another embodiment in which a filter cloth is suspended from the front of a diaphragm filter plate.
FIG. 6 is a longitudinal sectional view of another embodiment of the heating plate.
FIG. 7 is a side view of the dewatering cake peeling device.
[Explanation of symbols]
1, 15 Heating plate 1a, 3a, 12a, 15c Filtration bed 1e, 3e Vacuum suction hole 2, 4 Wedge wire 3 Filter plate 5 Filtration chamber 6 Heating pipe 7, 10 Diaphragm filter plate 8 Core plate 9, 12 Diaphragm 9a Surface 13 Filter cloth 15b Heat supply hole

Claims (6)

A heating chamber (5) is formed by alternately juxtaposing a heating plate (1) on which a metal filter medium is stretched and a filter plate (3) having a concave filtering surface, and a heating plate (1) and a filtering plate (3) are formed. In a filter press for discharging the dried cake generated in the filtration chamber (5) by opening the plate, wedge wires (2, 4) are stretched on the filtration surfaces of the heating plate (1) and the filtration plate (3) formed in a flat shape. Then, the vacuum suction holes (1e, 3e) communicating with the filtration chamber (5) are arranged in the heating plate (1) or the filter plate (3) while being in direct contact with the cake in the filtration chamber (5). A heated filter press characterized by the following. The heating type according to claim 1, wherein the wedge wires (2, 4) stretched on the filtration beds (1a, 3a) of the heating plate (1) and the filter plate (3) are made of punching metal. Filter press. The heated filter press according to claim 1 or 2, wherein a plurality of heating pipes (6) are arranged inside the filtration bed (1a) of the heating plate (1). The heating plate is provided with a heating fluid supply hole (15b) for a heating fluid on a heating plate (15) on which a wedge wire (2) is stretched. The heated filter press according to claim 1 or 2, wherein the filter is connected to (15c). Instead of the filter plate (3) with the wedge wire (4) stretched, a diaphragm filter plate (7) with a diaphragm (9) stretched on a core plate (8), and the surface (9a) of the diaphragm (9) The heated filter press according to any one of claims 1 to 4, wherein is formed into a flat shape and is directly contacted with the cake. The said diaphragm filter plate is a diaphragm filter plate (10) which stretched the diaphragm (12) which has a filtrate groove | channel, and the filter cloth (13) was suspended from the filtration bed (12a). Item 5. A heated filter press according to item 5.

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