JP2003112294A - High-pressure dehydrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-pressure dehydrator which can reduce the number of parts and the weight thereof by disposing a plurality of stages of fixed plates and pressing plates in a longitudinal direction, and using the fixed plates as supporting boards of the next stage. SOLUTION: This high-pressure dehydrator comprises two turning endless filter cloths 2 and 3, a plurality of stages of pressing units 4, 5, 6 and 7, and a plurality of rollers 8, 9 and 10. Each pressing unit has a fixed board and a supporting board facing each other with a space therebetween and a pressing means supported by the supporting board in the space, and the two filter cloths are wound via the rollers so as to pass through the space of each pressing unit while holding mud therebetween. The supporting board is also used as the fixed board of the pressing unit of the adjacent stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sludge dehydrator for dehydrating sludge generated in wastewater treatment and the like, and more particularly to a high pressure dehydrator for pressurizing and dehydrating by applying hydrostatic pressure.

[0002]

2. Description of the Related Art Conventionally, various types of dehydrators have been used to dehydrate sludge generated in wastewater treatment and the like. Among them, a dewatering machine called a filter press is particularly commonly used to obtain dewatered sludge having a low water content. This filter press has a diaphragm and a filter cloth in a cavity formed in a large number of pressure plates clamped by cylinders, etc., and is sandwiched in the filter cloth by expanding the diaphragm with pressure water or the like. The sludge is pressed and dehydrated. When the dehydration is completed, the pressure plate is unfastened to open the cavity, and the dehydrated sludge is discharged.

However, although this filter press can obtain dehydrated sludge having a low water content, the cycle time for one operation is long, the dehydrator itself becomes large and the equipment cost increases, and the pressurizing plates are connected in the lateral direction. Therefore, there is a problem that the installation space becomes large. As a solution to this problem, for example, Japanese Patent Application Laid-Open No.
There is a high-pressure type belt press dewatering machine disclosed in JP-A-0-334499. This dehydrator has three functions of gravity dehydration, shear dehydration with a belt press, and pressure compression dehydration, and dehydration sludge with a low water content equivalent to that of a filter press can be obtained. This high-pressure type belt press dewatering machine is equipped with a four-stage pressing unit, and two filter cloths are superposed and pressed and dehydrated while sequentially passing through the four-stage pressing unit in a zigzag shape. It is something. Each pressurizing unit is provided with a fixed plate and a pressure plate arranged above and below, and the diaphragm is expanded to push up the lower pressurizing plate, so that two overlapping filters are fixed between the fixed plate and the pressurizing plate. The sludge sandwiched between cloths is pressed and dehydrated.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Japanese Patent Publication No. 334499-A discloses a method for obtaining a dehydrated sludge having a schematic structure and a low water content equivalent to that of a filter press in a high-pressure belt press dehydrator. However, since the pressurizing unit is configured to include at least a fixed plate, a pressurizing plate, and a diaphragm, if a dehydrator having a multi-stage pressurizing unit includes a supporting mechanism for them, the number of parts increases, and the structure becomes considerably complicated. It is also a factor of increasing the weight of the dehydrator. Further, since a pressure of about 0.2 to 1.0 MPa is applied to each pressurizing portion, a large stress is applied to the fixing plate and the diaphragm receives the reaction force. Therefore, the fixing plate itself of each pressurizing section and the supporting member of the diaphragm must have a large thickness in order to secure high rigidity, which also causes an increase in weight of the dehydrator. Therefore, an object of the present invention is to solve the above problems of the conventional high-pressure type belt press dehydrator, and to provide a high-pressure type dehydrator having a reduced number of parts and a lighter weight.

[0005]

A high-pressure type dehydrator according to the present invention comprises two rotating endless filter cloths, a plurality of pressure sections, and a plurality of rollers. The pressure part has a fixed platen and a support platen which are arranged to face each other with a gap, and a pressurizing means which is supported by the support platen in the gap, and the two filter cloths sandwich sludge between them. A high-pressure type dehydrator that is wound around the rollers so as to pass through the gaps of the pressure units, wherein the support plate also serves as a fixing plate for the pressure units of adjacent stages. To do.

According to the high-pressure dehydrator of the present invention, the number of supporting plates and fixed plates can be reduced. For example, a dehydrator having four stages of pressurizing sections may be provided with five stages of support plates (fixed plates). Therefore, according to the high-pressure dehydrator of the present invention, it is possible to provide a high-pressure dehydrator in which the number of parts is reduced and the weight is reduced.

In the high-pressure dehydrator of the present invention, it is desirable that the supporting plate and / or the fixing plate have a sludge structure in which a plurality of steel blocks are arranged in parallel at predetermined intervals and integrated by a connecting member. As a result, the weight of the support plate and / or the fixed plate can be reduced, so that the weight of the dehydrator can be further reduced.

In the high-pressure type dehydrator of the present invention, it is desirable that the supporting plate and / or the fixing plate is made of cast steel and has a structure having a plurality of through-frame members. As a result, the weight of the support plate and / or the fixed plate can be reduced, so that the weight of the dehydrator can be further reduced.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a high-pressure dehydrator of the present invention will be described with reference to the drawings. FIG. 1 is a skeleton diagram showing the entire high-pressure dehydrator of the present invention. 10 in the figure
Reference numeral 0 is a gravity dehydration unit, and 1 is a pressure dehydration unit. Two filter cloths 2 and 3 are stretched around the pressure dehydration section 1, and the filter cloths 2 and 3 are superposed on each other to form a first pressure section 4, a first bending roll 8, and a second pressure section. 5, the second bending roll 9, the third pressing portion 6, the third bending roll 10, and the fourth pressing portion 7, and is separated by the separating rolls 11 and 12. Concentrated activated sludge having a water content of about 98.5% generated in the process of biologically purifying sewage including urban wastewater, industrial wastewater, etc. is supplied to the gravity dehydration unit 100 after adding a flocculant (not shown). Here, the sludge having a water content of 90 to 95% is made by gravity filtration.
This sludge is filtered from the gravity dewatering unit 100 to the filter cloth 2 of the pressure dewatering unit 1.
It is supplied above, is sandwiched between the two filter cloths at the overlapping portion of the filter cloths 2 and 3, and enters the first pressurizing section 4, where the first pressurizing and pressing is performed. Further, the second, third, and fourth pressurizations are performed by the second pressurizing unit 5, the third pressurizing unit 6, and the fourth pressurizing unit 7, so that the sludge has a low water content of about 68%. Be dehydrated. The dehydrated sludge is separated by the separating rolls 11 and 12, and the sludge attached to the lower filter cloth 2 among the filter cloths 2 and 3 is separated by the scraper 13 facing the lower separating roll 12. The sludge that has been scraped off and adhered to the filter cloth 3 is scraped off by the scraper 14 facing the upper separation roll 11 and discharged to the outside of the machine.

FIG. 2 is a view taken along the line AA of FIG. 1, and FIG. 3 is a view taken along the line BB of FIG. Since the pressure units 4, 5, 6, 7 have the same configuration, the fourth pressure unit 7 will be representatively described in the following description. The fourth pressurizing unit 7 is composed of an upper fixed plate 61 and a lower support plate 71, and the upper fixed plate 61 also serves as a lower support plate forming the third pressurizing unit 6. Fixed board 6
As shown in FIG. 2, the support 1 and the support board 71 are fitted and fixed in the grooves 151 and 151 formed in the frame members 15 and 15 arranged opposite to each other like a drawer of a desk. The frame 15 is a steel plate having a thickness of 60 mm to 80 mm, a groove 151 is formed on one surface of the frame 15 by machining, and the groove 151 suitable for locking the fixed plate and the support plate to the frame 15 is formed. Depth of 3
It is 0 mm to 40 mm. If it is shallower than this, locking becomes uncertain, and if it is deeper, the weight of the frame 15 increases.

A lower support board 71 which constitutes the fourth pressurizing section 7.
A diaphragm 72 serving as a pressing means, a receiving plate 73, a grating 74, and a pressing plate 75 formed of punching metal are arranged upward in this order. A receiving plate 62, a grating 63, and a pressure plate 64 formed of punching metal are provided below the upper fixed plate 61 that constitutes the fourth pressure unit.
Are arranged downward in this order. And the pressure plate 75
The filter cloths 2 and 3 that overlap each other are passed through the gap between the pressure plate 64 and the pressure plate 64. The diaphragm 72 has a bag-shaped structure, and when expanded by water pressure, the receiving plate 73, the grating 74, and the pressure plate 75 are all raised to push up the filter cloths 2 and 3 on which the pressure plates 75 are overlapped, and the filter cloths 2, 3 Is the upper fixed plate 61
The filter cloths 2 and 3 and the sludge sandwiched between them are pressed and pressed by being pressed against the pressure plate 64 supported by. That is, the fixed plate 61 and the support plate 71 are the diaphragm 72.
It has a function as a reaction member that receives the stress of.
When the pressing force is sequentially increased from the first pressurizing unit, the thickness of the support plates (fixed plates) 40, 41, 51, 61, 71 (hereinafter, simply referred to as the support plate) becomes smaller in the downstream stage. Enlarge. A method of supplying water for expanding the diaphragm 72 is a commonly used technique, and therefore, illustration and description thereof will be omitted.

[0012] Here, for example, in the case where the pressing force is 1.0 MPa and the pressing area is 7 m ² , a reaction force of 700 tons is applied to the support board 71 which constitutes the fourth pressing section, which is the final stage. Since the lowermost support plate 71 and the uppermost fixed plate 40 receive a reaction force from only one direction, they receive an extremely large load. Since the intermediate support plates 41, 51, 61 are stressed from both upper and lower directions, they are stressed by the pressure difference. However, it may be considered that the intermediate support board is also stressed only from one direction due to the difference in the rising speed of the pressurization force of each pressurizing section and the lack of pressure due to the failure of some diaphragms.
In such a case, the support board of each pressurizing section must have sufficient rigidity to receive the stress of the pressurizing section. In the high-pressure dehydrator of the present invention, for example, adding a support pillar or the like for supporting the central portion of the support board,
This cannot be done because it interferes with the running range of the lower filter cloth 2. Therefore, the supporting board, especially the lowermost supporting board, needs to be strong, and the engaging portion with the frame body that supports the supporting board must also have a strong structure.

The supporting plate needs to have a so-called large depth, and has a saw-tooth structure in which the steel blocks shown in FIGS. 4 and 5 are arranged at a predetermined interval, and a cast steel shown in FIGS. 6 and 7. The machined structure of the extremely thick steel plate shown in FIGS. 8 and 9 can be used. However, the support board 71 ′ ″ having the structure shown in FIGS. 8 and 9 is not preferable because the weight increases.

The supporting board will be described with reference to the sludge structure shown in FIG. 4 and the cast steel shown in FIG. The support board 71 'is shown in FIG.
As shown in FIG.
12 in parallel with each other,
Both ends of 11 are welded and fixed by a connecting member 713. This support board 71 ′ is a block 711 that constitutes it.
Both ends 711a, 711b of the groove 1 of the frame 15 described above.
It is fitted so as to fit into 51. With such a structure of the support board, it is possible to reduce the weight without lowering the strength. In the cast steel support plate 71 ″ shown in FIG. 6, each of the bone members 715 is a through member, and both ends thereof are fitted into the grooves 151 of the frame body 15. By providing the hollow portion 716, the weight can be reduced without lowering the strength.

The combination of the support board 71 and the frame 15 can be realized by fixing each support board so as to be embedded in the groove 151 of the frame 15 as shown in FIG. The reaction force acting on can be received in the frame and the support board, so that no external force is exerted. Therefore, it is not necessary to use a powerful cylinder and a strong base pedestal attached to it, which is required in conventional filter presses.

Next, the operation of the above configuration will be described. The filter cloths 2 and 3 are configured to run and stop for a distance corresponding to the length L of the pressing portions 4, 5, 6, and 7 shown in FIG. 1 for each pressing operation. By doing so, it is possible to apply the pressurizing operation from the first pressurizing unit to the fourth pressurizing unit sequentially to the filter cloths 2 and 3 and all the sludges sandwiched therein. The pressure of the pressurizing operation is, for example, 0.3 MPa for the first pressurizing section 4, 0.6 MPa for the second pressurizing section 5, 0.8 MPa for the third pressurizing section 6, and 1. MPa for the fourth pressurizing section 7. Inject pressure water of 0 MPa to each stage diaphragm. When applying pressure, first filter cloths 2 and 3
After the traveling of No. 1 is stopped, the pressure water is supplied to the diaphragm 73. Since the fourth pressurizing section 7 pressurizes and compresses at a pressure of 1.0 MPa, pressure water of 1.0 MPa is used.
The diaphragm 72 expands and raises the receiving plate 73, the grating 74, and the pressure plate 75 installed on the upper side of the diaphragm 72. Then, the pressure plate 75 presses the filter cloths 2 and 3 against the pressure plate 64 on the upper side and squeezes them. At this time, filtered water is squeezed out of the sludge, and this filtered water escapes from the holes of the pressure plates 64 and 75 formed by punching plates, passes through the gratings 63 and 74, and passes through a discharge pipe (not shown). Is discharged outside the aircraft.

The receiving plates 62 and 73 are gratings 63 and 74.
And supports the support board 61 and the diaphragm 72 from the gratings 63 and 74. Also,
Filtered water together with gratings 63 and 74
It functions to lead to the water collecting trays 76, 76 on the fifth side.

When one pressurizing operation described above is completed, the filter cloths 2 and 3 are run for a distance L and then stopped to perform the next pressurizing operation. By doing so, the filter cloths 2, 3 and all the sludges sandwiched by the filter cloths are subjected to the pressurizing operation by the pressurizing sections 4, 5, 6, 7 and, as mentioned above, are successively subjected to the strong pressurizing operation, so that they are low in pressure. Dehydrated to moisture content.

[0019]

EFFECTS OF THE INVENTION Since the present invention has the above-mentioned structure, it is possible to provide a high-pressure dehydrator which can reduce the number of supporting plates and which is lighter in weight. Further, by configuring the support board as described above, it is possible to provide a high-pressure dehydrator having a further reduced weight.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing an outline of a high-pressure dehydrator of the present invention.

FIG. 2 is a view on arrow AA of FIG.

3 is a BB arrow view of FIG. 2. FIG.

FIG. 4 is a front view of a supporting board having a sludge structure used in the high-pressure dehydrator of the present invention.

FIG. 5 is a side view of FIG.

FIG. 6 is a front view of a cast steel support board used in the high-pressure dehydrator of the present invention.

FIG. 7 is a side view of FIG.

FIG. 8 is a front view of an extremely thick steel plate support plate used in the high-pressure dehydrator of the present invention.

9 is a side view of FIG.

[Explanation of symbols]

1 Pressurized dehydration unit 2,3 filter cloth 4 First pressure part 5 Second pressure part 6 Third pressurizing unit 7 Fourth pressurizing unit 8 First bending roll 9 Second bending roll 10 Third bending roll 11,12 Separation roll 13,14 scraper 15 frame 40 fixed board 41,51,61 Support board (fixed board) 62,73 support plate 63,74 Grating 64,75 pressure plate 71, 71 ', 71 ", 71"' support board 711 blocks 712 gap 713 tie material 715 bone member 72 Diaphragm (pressurizing means) 100 Gravity dehydration unit 151 groove

Claims (3)

[Claims] 1. A stationary platen comprising two rotating endless filter cloths, a plurality of pressure units, and a plurality of rollers, each pressure unit facing each other with a gap therebetween. A support plate and a pressurizing means supported by the support plate in the gap, and the two filter cloths sandwich the sludge between them and are wound around the roller so as to pass through the gap. It is a pressurization type dehydrator, Comprising: The said support board serves also as the fixing board of the pressurization part of an adjacent stage, The high pressurization type dehydrator characterized by the above-mentioned. 2. The high-pressure dehydrator according to claim 1, wherein the supporting plate and / or the fixing plate has a sludge structure in which a plurality of steel blocks are arranged in parallel at predetermined intervals and integrated by a connecting member. 3. The high-pressure dehydrator according to claim 1, wherein the supporting plate and / or the fixing plate is made of cast steel and has a structure having a plurality of through-frame members.