JP2003136099A - Sludge dehydration method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance treatment capacity and to reduce the water content of a cake to enhance the peelability of the cake. SOLUTION: A diaphragm 2E made of a resin compressing sludge is arranged between a compression filter plate 2 on one side and the filter cloth 4 opposed thereto so as to hold a filter chamber 6 and the space between the diaphragm 3E and the compression filter plate 2 on one side is set to a fluid chamber 2D and the diaphragm is not arranged between the heating filter plate 3 on the other side and the outer surface of the filter cloth 4 opposed thereto but a hollow heat conductive plate 30 is arranged to the heating filter plate 3. The hollow space of the heat conductive plate 30 is set to a heating chamber 3s and a heating fluid is supplied to the heating chamber 3s. Under this constitution, the blow discharge of filtrates is performed after compression.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to drainage of tap water sludge and sewage treatment plants, industrial wastewater or general chemical and dehydration of food-related sludge, and pressure filtration and press dehydration of sludge. The present invention relates to a sludge dewatering method using a filter press device including a press type filter press.

[0002]

2. Description of the Related Art Conventionally, tap water sludge and the like have been dehydrated by using a filter press. Especially in recent years, because of the lack of treatment capacity of equipment due to deterioration of water quality,
As a solution to this, the sludge supplied to the filter press was heated to improve the processing capacity.

[0003]

However, although such a conventional technique can improve the treatment capacity to some extent, it is difficult to further reduce the water content of the dehydrated cake and remarkably enhance the peelability of the thin dehydrated cake. And
At present, there is no effective means for shortening the filtration and squeezing time.

Therefore, the main object of the present invention is to reduce the water content of the dehydrated cake and improve the peelability of the dehydrated cake while shortening the filtration and squeezing time while improving the treatment capacity. .

[0005]

The present invention which has solved the above-mentioned problems is as follows. <Invention according to claim 1> A filter cloth is provided so as to face each other in a filter chamber between the filter plates facing each other, sludge is supplied between the filter cloths for filtering, and a filter facing one pressing filter plate is provided. A diaphragm is provided between the cloth and the hollow heat conduction panel is arranged between the other heating filter plate and the filter cloth which directly faces the filter, and a filter press device equipped with a pneumatic means is used. Filtration is performed while heating the sludge supplied between the filter cloths by passing a heating fluid through the hollow heat conduction panel, and the filtrate is discharged through the filtrate discharge passage, and in the pressing step after the filtering step, the diaphragm is used. Is swelled from the squeezing filter plate side to the warming filter plate side for squeezing, and the filtrate is discharged through a filtrate discharge path, and after the squeezing step, compressed air is supplied into the filter chamber, and the remaining filtrate is discharged. Of sludge, which is characterized by discharging the Water method.

<Invention according to claim 2> A filtrate groove is formed on the surface of the hollow heat conduction panel facing the filter cloth, and the filtrate passes through the filtrate groove. The filtrate remaining in the filtrate groove is placed in the filter chamber. The sludge dewatering method according to claim 1, wherein the sludge is discharged to the outside by supplying compressed air.

<Invention according to Claim 3> A filtrate groove is formed on the surface of the hollow heat-conducting panel facing the filter cloth, and the filtrate passes through the filtrate groove, and the heating fluid passes through the hollow heat-conducting panel. The sludge dewatering method according to claim 1, wherein the filtrate remaining in the filtrate groove is discharged to the outside by supplying pressurized air into the filter chamber.

<Invention according to claim 4> A filtrate groove is formed on the surface of the hollow heat conduction panel facing the filter cloth, and the filtrate passes through the filtrate groove, and a filtrate groove is formed on the surface of the diaphragm facing the filter cloth. The sludge dewatering method according to claim 1, wherein the filtrate is configured to pass through the filtrate groove, and the filtrate remaining in each of the filtrate grooves is discharged to the outside by supplying pressurized air into the filter chamber.

<Invention of Claim 5> Filter cloths are provided facing each other in a filter chamber between opposed filter plates, and sludge heated outside is supplied between the filter cloths through an external sludge supply passage. Doing so, a diaphragm is provided between one squeezing filter plate and the facing filter cloth, and a hollow heat transfer panel is arranged between the other heating filter plate and the directly facing filter cloth,
Using a filter press device in which a cleaning liquid supply path and an external compressed air supply path are connected to the external sludge supply path, the sludge supplied between the filter cloths is passed by passing a heating fluid through the hollow heat conduction panel during the filtration process. Filtration is performed while heating, and the filtrate is discharged through the filtrate discharge passage, and in the pressing step after the filtering step, the diaphragm is swelled from the pressing filter plate side to the heating filter plate side for pressing. , The filtrate is discharged through the filtrate discharge path, and after the pressing step, the cleaning water is supplied from the cleaning liquid supply path to blow the sludge in the external sludge supply path, and then the compressed air is supplied into the filter chamber. And the remaining filtrate is discharged to the outside.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It has been conventionally known that when heated sludge is supplied at the time of filtration, the filtration capacity is improved. In the present invention, the means is adopted, or sludge supplied between filter cloths is used. Either adopt a heating method, or use both methods together.

However, even if the heated sludge is supplied, the temperature is lowered within the time until the completion of the filtration and dehydration, and the dehydratability is deteriorated with time. Further, even if the sludge supplied to the filter chamber is heated, a part of the heat is released to the outside of the device through a heat transfer path such as a filter plate,
Heat transfer efficiency to sludge is not good.

Therefore, in the present invention, it is possible to heat the sludge in the filter chamber and to transfer heat to the sludge with high efficiency. As a result, it is possible to prevent a decrease in filtration dehydration property due to a decrease in temperature in the filtration step.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a front view of an example of a filter press device according to the present invention, and FIG. 2 is its II-II.
A cross-sectional view is shown, and FIG. 3 shows the filter plate arrangement form.
As shown in FIG. 3, the present device 1 includes a filter plate 2 (hereinafter, also referred to as a pressing filter plate) having a diaphragm 2E provided on the surface of each filter cloth 4, and a filter plate 3 having no diaphragm (hereinafter referred to as a filter plate 3). , Also referred to as a heating filter plate) are alternately arranged in the horizontal direction, and the filter plates are of the horizontal type because of the arrangement form. This heating filter plate 3 is also shown in FIGS. 2 and 3.

The example of the present apparatus belongs to a so-called intaglio type filter plate, and the filter plates 2 and 3 are provided with recesses 2a and 3a on the surfaces facing the adjacent filter plates 3 and 2, respectively. , And a pair of filter cloths 4, 4, ... Are hung between the adjacent filter plates 2, 3.

These filter plates 2, 3 ... Are connected to adjacent filter plates via connecting members 109, 109, and their mutual intervals are adjusted by a horizontally extending cylinder 5. There is. Further, a shaft 103 is horizontally supported on the filter plates 2 and 3, and can be rotated forward and backward by a filter cloth driving device 102.
The filter cloths 4 and 4 are supported in a suspended state via the wire rope 105 that can be wound by the pulleys 104 and 104 attached to the cable 03 and the support bar 108 connected to the lower end of the wire rope. ing.
Then, after the support bar 108 for suspending the filter cloth is pulled up to the upper limit, the adjacent filter plates 2 and 3 are brought into contact with each other by the extension of the cylinder 5 and tightened, so that as shown in FIG. A filter chamber 6 surrounded by a pair of filter cloths 4 and 4 is formed between the three. An external sludge supply passage 7F, which will be described later, is provided in the filter chamber 6 for heating the filter plate 3
Through internal sludge supply passages 31 (see also FIG. 2). The lower structure of the filter plate will be described later.

In this embodiment, in particular, each squeezing filter plate 2 is made of resin and has concave portions 2a, 2 facing the outer surfaces of the filter cloths 4, 4.
Resin diaphragms 2E, 2E having filtrate grooves 2e, 2e ... Formed on the surface thereof are arranged so as to cover a, and fluid chambers 2D, 2D are provided between the diaphragms 2E, 2E and the outer surface of the press filter plate 2. Each is formed. Each fluid chamber 2
Internal fluid supply / discharge passages 2F communicate with D and 2D, respectively. Therefore, the fluid F can be supplied to and discharged from the fluid chambers 2D and 2D. Further, a gap SP1 (including inside the filtrate grooves 2e, 2e ...) Between the filtrate grooves 2e, 2e ... Of the diaphragms 2E, 2E and the outer surface of the filter cloth 4 facing this.
Have internal filtrate discharge passages 2H and 2H communicating with each other at their lower ends and an internal compressed air supply passage 2J at their upper ends.
Are known to each other.

On the other hand, the heating filter plate 3 is also made of resin, and the hollow heat conduction panel is provided with filtrate grooves 3e, 3e ... On the surfaces of the recesses 3a, 3a facing the outer surfaces of the filter cloths 4, 4, respectively. 30 (example: a metal panel) is fitted into each of the heat conduction panels 30, and heating chambers 3s through which a heating fluid flows are formed in the hollow spaces of the heat conduction panels 30, and at the lower end and the upper end of the heating greenhouse 3s. The internal fluid supply passage 3F and the internal fluid discharge passage 3G are communicated with each other. Therefore, the squeezing filter plate 2 is included in the warming filter plate 3.
No diaphragm is arranged between the outer surface of the filter cloth 4 and the outer surface of the filter cloth 4 which face each other. Further, the clearance SP2 between the filtrate grooves 3e, 3e ... And the outer surface of the filter cloth 4 which faces the filtrate grooves 3e, 3e.
(Including inside), at the lower end thereof, the internal filtrate discharge passage 3H
And the internal pressure supply passages 3J communicate with each other at their upper ends.

Thus, in the present device 1, the main members such as the warming filter plate 3, the pressing filter plate 2 and the diaphragm 2E facing the outside of the device 1 are made of resin, and the filter chamber 6 surrounded by them is formed. From outside to the device, and heat conduction and heat dissipation from the heat conducting panel 30 (these correspond to the heating portion of the supply sludge heating means) to outside the device are suppressed, and the sludge in the filter chamber 6 is suppressed. It is possible to keep the temperature of the above and heat transfer to the sludge in the filter chamber 6 with high efficiency.

Further, in the present apparatus 1, a diaphragm 2E for squeezing the sludge supplied to the pair of filter cloths 4 and 4S is disposed between the pressing filter plate 2 and the filter cloth 4 facing the pressing filter plate 2, and A fluid chamber 2D is formed between the diaphragm 2E and the squeezing filter plate 2, while no diaphragm is arranged between the heating filter plate 3 and the filter cloth 4 facing the heating filter plate 3 and the heating filter plate 3 is provided. Is provided with a heating means (the greenhouse 3s constitutes a heating means) for heating the supplied sludge.

On the other hand, referring to the system flow diagram of FIG. 4, in the example of the present device, the sludge storage tank 7A and the sludge S in the sludge storage tank 7A are added as the sludge supply means 7 for supplying the warmed sludge. Sludge heating means 7B (for example, steam blowing device) for heating, and sludge storage tank 7A
There is provided a sludge pump 7P for supplying the heated sludge S in the inside thereof to the filter cloths 4 and 4S under pressure via the external sludge supply passage 7F. A washing valve 8V is installed in the external sludge supply passage 7F.
A cleaning liquid supply passage 8F having f is communicated with it, and a sludge blow passage 8B having a sludge blow valve 8Vb is branched from the external sludge supply passage 7F, and the sludge blow passage 8B communicates with a sludge storage tank 7A. Illustrated 7
Vf represents a sludge supply valve arranged between the communicating portion of the cleaning liquid supply passage 8F in the external sludge supply passage 7F and the outlet side of the sludge pump 7P.

Further, as a means 9 for supplying a heating fluid (warm water, steam or the like) F to the heating chamber 3s in the heat conduction panel 30 in order to heat the supplied sludge, a fluid storage tank 9A.
A fluid heating means 9B (for example, a steam blowing device) for heating the fluid F in the fluid storage tank 9A;
A heating fluid supply pump 9P for supplying the heating fluid F therein to the greenhouse 3s via the external fluid supply passage 9F and the internal fluid supply passage 3F is provided. 9 Vf is the fluid supply path 9
9 shows the heating fluid supply valve arranged at F. An internal fluid discharge channel 3G communicates with the upper part of the heating chamber 3s, and the warming fluid supplied into the heating chamber 3s flows through the internal fluid discharge channel 3G and the fluid return channel 12 into the fluid storage tank 9
It will be returned to A.

Further, in this embodiment, the heating fluid F is supplied into the above-mentioned fluid chamber 2D and is used for expanding the diaphragm 2E. Specifically, it is provided with a press-fitting pump 10P that pressurizes and supplies the heating fluid F in the fluid storage tank 9A into the fluid chambers 2D, 2D via the external fluid supply passage 10F and the internal fluid supply passage 2F. Reference numeral 10Vf indicates a fluid inlet valve arranged in the external fluid supply passage 10F. With this configuration, some heat conduction can be expected through the diaphragm 2E even when the resin diaphragm is used, so that the diaphragm 2 with respect to the supplied sludge can be expected.
E will start to be heated. Further, the external fluid supply passage 10F branches off from a portion between the fluid inlet valve 10Vf and the internal fluid supply passage 2F to form a fluid storage tank 9A.
Is provided with a return passage 10R communicating with the fluid chamber 2D, and a relief valve 10Vr is provided in the return passage 10R.
The supply pressure of the heating fluid to the 2D is also maintained below the set pressure of the relief valve.

Further, in the example of the present device, the filtrate outlet valves 11 while the inner filtrate discharge passages 2H and 3H of the filter plates 2 and 3 are joined.
Filtrate tank 11 via external filtrate discharge passage 11H having Ve
The filtrate in the filtrate tank 11A is supplied to the filtrate storage tank 11C by the filtrate pump 11B according to the amount of the stored filtrate. In addition, the external filtrate discharge path 1
A filtrate blowing passage 11J having a filtrate blowing valve 11Vb is branched from 1H, and the filtrate blowing passage 11J communicates with a filtrate storage tank 11C. Preferably, as in the illustrated example, a vacuum pump 11D is connected to the filtrate tank 11A in advance, and the filtrate grooves 2e and 3e and the filter cloth are filtered by the vacuum pump 11D via the filtrate tank 11A and the filtrate discharge paths 2H and 3H. The gaps SP1 and SP2 with the gaps 4 and 4 are configured to be negative pressure. Further, as in the illustrated example, the compressed air supply paths 2J, 3J
If the gaps SP1 and SP2 between the filtrate grooves 2e and 3e and the outer surface of the filter cloth 2B can be sucked from the upper part of the gap to a negative pressure through the upper suction passage 14 and the negative pressure can be obtained, the dehydrated substance can be efficiently and uniformly dehydrated. Will be possible.

Further, in the example of the present apparatus, the internal compressed air supply passage 2
External pressure supply line 13J and pressure tank 1 for J and 3J
Compressed air (for example, compressed air) from the compressor 13C is supplied via 3A.

<Example of Dewatering Method> Next, an example of the sludge dewatering method of the present invention using the above-described dewatering apparatus 1 will be described.
The present dehydration method example mainly includes a filtration step and a subsequent compression step.

In the filtration process, first the cylinder 5
By extending (only in FIG. 1), the filter plates 2, 3 ... Are tightened to close the frame, and the filter chamber 6 is formed as shown in FIG. Also,
Keep all valves closed. Then, the heating fluid supply pump 9P is operated and the fluid inlet valve 9Vf is opened. As a result, the warming fluid F (warm water or steam) warmed by the warming means 9B enters the heating chamber 3s of the heat conduction panel 30 from the fluid storage tank 9A via the external fluid supply passage 9F and the internal fluid supply passage 3F. Supplied. In this example,
The warming fluid F supplied to the warming greenhouse 3s is the upper fluid discharge path 3
After being returned to the fluid storage tank 9A through G and the fluid return path 12 and heated by the heating means 9B, the heating chamber 3 is again heated.
sent to s. By performing the circulation in this manner, the newly heated warming fluid F always exists in the warming room 3s.

Simultaneously with or subsequent to this, the sludge pump 7P is operated, the sludge supply valve 7Vf is opened, and the warmed sludge S which has been warmed in advance by the warming means 7B and stored in the sludge storage tank 7A.
Is pressurized and supplied between the filter cloths 4 and 4 of the filter chamber 6 through the external and internal sludge supply paths 7F and 31. This state is shown in Figure 5.
Is shown in. In the sludge S1 in the filter chamber 6, only the filtrate passes through the filter cloths 4 and 4 due to the supply pressure of the sludge that is sequentially sent, and the filtration proceeds. At this time, the heat of the heating fluid F passing through the inside of the heating chamber 3s is transmitted to the sludge between the filter cloths 4 and 4 through the heat conduction panel 30, and the sludge is heated while the filtration proceeds. Become.

At this time, either one of the filtrate outlet valve 11Ve and the filtrate blow valve 11Vb is left open, and in any case, the filtrate is filtered with the filtrate groove 2e of the diaphragm 2E,
..., filtrate groove 3e of heat conduction panel, ..., internal filtrate discharge path 2
It is discharged into the filtrate storage tank 11C via H, 3H and the external filtrate discharge passage 11H (details will be described later).

After a predetermined time has passed, for example, the sludge pump 7
P is stopped and the sludge supply valve 7P is closed to end the filtration process, and then the compression process is performed (the compression process may be performed while continuously supplying the sludge).

In the squeezing step, the heating fluid F is being supplied to the heating chamber 3s in the heat conduction panel 30 of the heating filter plate 3 (preferably, it is preferably continuously supplied from the filtering step). It is preferable to press fit the fluid into the chamber 2D. That is, in the case of the illustrated example, the heating fluid supply valve 10V
While opening f, the warming fluid press-fitting pump 10P is operated to press the warming fluid F stored in the warming fluid storage tank 9A into the fluid chamber 2D via the warming fluid press-fitting passage 10F and the internal supply passage 2F. Supply. The supply pressure at this time is maintained below the set pressure by the action of the relief valve 10Vr as described above. As a result, as shown in FIG.
Since the internal pressures of D and 2D become higher than the internal pressure of the filter chamber 6, the differential pressure causes the diaphragm 2E to bulge from the compressed filter plate 2 to the warming filter plate 3 and the bulged diaphragm 2E to the filter chamber. Sludge S1 to be dehydrated in 6 is filter cloth 4, 4
It is pinched through and squeezed.

Thus, even during pressing, the heating chamber 3s
The heating fluid F passing through the inside mainly passes through the heat conduction panel 30,
In addition, the heating fluid in the fluid chamber 2D is supplemented by the diaphragm 2
Through E, the sludge between the filter cloths 4 and 4 is effectively heated. As a result, at least the sludge between the filter cloths 4 and 4 is kept warm. By such heating, highly efficient press filtration is performed.

After a lapse of a predetermined time, the heating fluid supply valve 10Vf is closed, the heating fluid pressure pump 10P is stopped, and the fluid return valve 4Vb is opened. As a result, the fluid chamber 2D is returned to the fluid storage tank 9A via the fluid return passage 4C.

In the present invention, the squeezing operation and the returning operation can be alternately repeated during the squeezing step (usually repeated several times). As a result, the sludge is kneaded and unwound, and the filtering action by pressing can be promoted.

Further, it is possible to repeat a series of cycles of filtering operation, pressing operation and returning operation. In this case, since the object to be dehydrated after pressing has a small volume, the filter cloths 4 and 4 have a small volume. Further, the warmed sludge can be press-fitted (in this case, the diaphragm 2E is pushed back to the state shown in FIG. 5), and not only the filtration action by the squeezing is promoted but also the amount of sludge S supplied (injected) is dramatically increased. It is possible to increase.

When the pressing process is completed, the press-fitting pump 1
Stop OP and close the open valve.

Here, the discharge form of the filtrate in these filtering step and squeezing step can be selected mainly from the following methods. That is, the first method is a method of opening the filtrate outlet valve 11Ve and closing the filtrate blow valve 11Vb, and operating the vacuum pump 11D. Thereby, the filtrate tank 11A, the external filtrate discharge passage 11H, the internal filtrate discharge passages 2H, 3H, the filtrate grooves 2e of the diaphragm 2E, ... And the heat transfer panel 30 which constitute the filtrate discharge passage.
Since the filtrate grooves 3e, ... Of have a negative pressure, discharge of the filtrate during filtration or compression can be promoted, and the water content of the dehydrated cake can be lowered. In this case, the filtrate is diaphragm 2E
, And the filtrate grooves 3e, ... Of the heat transfer panel 30, and are sent to the filtrate tank 11A via the internal filtrate discharge paths 2H, 3H and the external filtrate discharge path 11H.
It is temporarily stored in the filtrate tank 11A. And filtrate tank 1
The filtrate in the filtrate tank 11A is pumped out by the filtrate pump 11B that automatically operates according to the amount of filtrate stored in 1A,
It is discharged into the filtrate storage tank 11C.

In the second method, the filtrate blow valve 11Vb is opened, the filtrate outlet valve 11Ve is closed, and the vacuum pump 11D is used.
Is a method that does not operate. In this case, the filtrate passes through the filtrate grooves 2e, 2e, ... Of the diaphragm 2E and the filtrate grooves 3e ,.
H, 3H, external filtrate discharge passage 11H, filtrate blow passage 11J
It is directly discharged to the filtrate storage tank 11C via.

The most effective method is to open the filtrate blow valve 11Vb and close the filtrate outlet valve 11Ve during the filtration step to allow the filtrate to flow down naturally, and to perform the same for a predetermined time even after entering the compression step. Later, when the amount of the filtrate became small, the filtrate outlet valve 11Ve was opened and the filtrate blow valve 11 was opened.
This is a method in which Vb is closed and, at the same time, the vacuum pump 11D is operated to make the filtrate discharge path 11H a negative pressure. In this method, while the filtrate is naturally discharged, the filtrate discharge path 11H
The negative pressure is applied to the filtrate discharge path 11H from the time when the filtrate becomes difficult to be discharged naturally, so that the filtrate discharge is promoted and the cake water content is lowered, while the filtrate is constantly discharged in the filtration step or the squeezing step. Compared with the case where the filtrate discharge path 11H is set to a negative pressure, there is an advantage that the energy consumption by the vacuum pump 11D can be reduced.

On the other hand, it is recommended to carry out the blowing step after the above-mentioned squeezing step and filtration step are completed. In the main blowing process, the washing valve 8Vf and the sludge blow valve 8Vb are opened, and the sludge in the sludge supply path including the external sludge supply path 7F is blown to the sludge storage tank 7A by the wash water.

Next, the cleaning valve 8Vf is closed and the compressed air inlet valve 13Vf is opened, and as shown in FIG. 7, the compressed air stored in the compressed air tank 13A by the compressor 13C is used to supply the external compressed air supply passage 13J and the internal compressed air supply passage. Two
J, 3J, diaphragm 2E, filtrate grooves 2e, 2e of 2E
And the cleaning water remaining in the sludge supply path including the external sludge supply path 7F is blown to the sludge storage tank 7A while being blown through the filtrate grooves 3e of the heat transfer panel 30. Preferably, such pressure air blowing is performed before and after the washing water blowing.

More preferably, after the lapse of this predetermined time, the sludge blow valve 8Vb is closed, the fluid blow valve 4Vb and the filtrate blow valve 11Vb are opened, and the pressurized air supplied subsequently is supplied into the filter chamber 6 this time. Then, by the action of the supply air into the filter chamber 6, the warmed fluid in the fluid chamber 2D is returned to the fluid storage tank 9A via the fluid blow passage 4C, and at the same time, the filtrate grooves 2e, ... The filtrate remaining in the filtrate grooves 3e, ... Of the panel 30 is blown into the filtrate storage tank 11C via the internal filtrate discharge passages 2H and 3H, the external filtrate discharge passage 11H, and the filtrate blow valve 11Vb.

The filtration, squeezing and blowing steps have been completed,
Since the dehydrated cake K is formed in the filter chamber 6, the draining process is started. In the discharging process, first, as can be understood from the comparison between FIG. 8 and FIG. 1, the cylinder 5 is contracted to open the loose head 101, and the filter plates 2, 3 ... It is pulled sequentially, and the frame is opened so that the intervals between the filter plates 2 and 3 are constant. Subsequently, the drive shaft 103 is rotated by the filter cloth drive device 102, and the pulley 1
The wire rope 105 wound around 04 is wound out, and each filter cloth 4 is wound around each winding roll 107 via each return roll 106 so that the lower ends of the filter cloths 4 and 4 that have been stuck together are opened. This winding is performed according to the amount of lowering of the filter cloth as the wire rope 105 is unwound, and the filter cloths 4 and 4 are always pulled between the support bar 108 and each of the return rolls 106 to form a substantially flat surface. It

Thus, the return rolls 106, 106
The dehydrated cake K formed between the filter cloths 4 and 4 is peeled from the filter cloths 4 and 4 and discharged due to the effect of the sharp folding back of the filter cloths 4 and 4 and its own weight. Usually, the dehydrated cake K can be peeled off only by driving the filter cloth, but if the peelability is poor, the return rolls 106, 4 are sandwiched between the filter cloths 4, 4.
A scraper (not shown) for scraping the cake from the filter cloth 4 may be provided on the opposite side of the filter cloth 4, and the dehydrated cake attached to the filter cloths 4 and 4 may be positively peeled off.

<Others> The diaphragm 2E of the present invention can be formed of a resin such as a rubber material. At least a portion of the diaphragm 2E corresponding to the filter chamber through the filter cloth is made of a material having a high thermal conductivity, for example. It is preferable to use a thin steel plate having flexibility (a stainless steel plate is preferable from the viewpoint of rust prevention). For example,
Although not shown, the outer edge portion of the diaphragm that does not substantially contribute to the heat retention effect is formed of a flexible material having low thermal conductivity such as a rubber material, and the central portion that substantially contributes to the heat retention effect is made of metal or the like. It can also be formed of a hard material having high thermal conductivity.

In the above description, an example of application to a filter cloth traveling type is shown, but the present invention is also applicable to a filter cloth hanging type dehydrator. Further, in the present invention, in addition to the upper feed for supplying sludge from the upper part of the filter plate as in the above-mentioned example, it is used as a center feed for supplying warmed sludge from the central part of the filter plate, or underfeed for supplying sludge from the lower part of the filter plate. You can also

Further, in the present invention, the opening / closing of the valve, the start / stop of the pump, the closing / opening of the frame by the cylinder, etc. in the above-described specific example can be automatically controlled by an appropriate control device.

[0047]

As described above, according to the present invention, it is possible to increase the injection amount of sludge, shorten the filtration and squeezing time, significantly reduce the water content of the dehydrated cake, and improve the peelability of the dehydrated cake. Therefore, the filtration and dehydration ability can be enhanced as a whole.

[Brief description of drawings]

FIG. 1 is a front view of an example of a filter press device according to the present invention.

FIG. 2 is a vertical sectional view showing a II-II section of FIG.

FIG. 3 is a longitudinal sectional view of an essential part showing an arrangement form of filter plates.

FIG. 4 is a flow chart showing an example of a filter press device according to the present invention.

FIG. 5 is a longitudinal sectional view of an essential part showing a filtration step.

FIG. 6 is a vertical cross-sectional view of a main part showing a squeezing step.

FIG. 7 is a longitudinal sectional view of an essential part showing a blowing step.

FIG. 8 is a longitudinal cross-sectional view of a main part showing a cake discharging step.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Filter press device, 2 ... Squeeze filter plate, 3 ... Heating filter plate, 4 ... Filter cloth, 2E ... Diaphragm, 2D ... Fluid chamber.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hironori Aoyagi             Tsukishima Machine, 2-17-15 Tsukuda, Chuo-ku, Tokyo             Within the corporation (72) Inventor Akio Koike             Tsukishima Machine, 2-17-15 Tsukuda, Chuo-ku, Tokyo             Within the corporation F term (reference) 4D018 AA01 AA06 AA12 BB02 BB04                       BB14 BB19 BB33                 4D059 AA03 AA30 BE16

Claims (5)

[Claims] 1. A filter cloth is provided so as to face each other in a filter chamber between opposed filter plates, sludge is supplied between the filter cloths for filtering, and between one squeezing filter plate and the facing filter cloth. A hollow heat conducting panel is provided between the heating cloth and a filter cloth which directly faces the other heating filter plate, and the hollow heat conducting panel is used during the filtration step by using a filter press device equipped with a pneumatic means. Filtration is performed while warming the sludge supplied between the filter cloths by passing a warming fluid through the filter cloth, and the filtrate is discharged through the filtrate discharge passage. In the compression step after the filtration step, the diaphragm is compressed and filtered. It swells from the plate side to the heating filter plate side and squeezes it, discharges the filtrate through the filtrate discharge path, and after the pressing step, supplies compressed air into the filter chamber and discharges the remaining filtrate to the outside. A method for dehydrating sludge, which comprises: 2. A filtrate groove is formed on the surface of the hollow heat transfer panel facing the filter cloth, and the filtrate passes through the filtrate groove, and the filtrate remaining in the filtrate groove is supplied to the filter chamber with compressed air to the outside. The sludge dewatering method according to claim 1, wherein the sludge is discharged to the air. 3. A filtrate groove is formed on the surface of the hollow heat transfer panel facing the filter cloth, and a filtrate passes through the filtrate groove and a heating fluid passes through the hollow heat transfer panel. The sludge dewatering method according to claim 1, wherein the remaining filtrate is discharged to the outside by supplying compressed air into the filter chamber. 4. A hollow heat conduction panel is provided with a filtrate groove on the surface facing the filter cloth, the filtrate passes through the filtrate groove, and a filtrate groove is formed on the surface of the diaphragm facing the filter cloth. 2. The sludge dewatering method according to claim 1, wherein the filtrate remaining in each of the filtrate grooves is discharged to the outside by supplying compressed air to the filter chamber. 5. A filter cloth is provided so as to face each other in a filter chamber between opposed filter plates, and sludge heated outside is supplied between the filter cloths through an external sludge supply passage to be filtered.
A diaphragm is provided between one squeezing filter plate and the facing filter cloth, and a hollow heat conduction panel is arranged between the other heating filter plate and the facing filter cloth, and a cleaning liquid is provided in the external sludge supply passage. Using a filter press device in which a supply path and an external compressed air supply path are connected, filtration is performed while heating the sludge supplied between the filter cloths by passing a heating fluid through the hollow heat conduction panel during the filtration process. The filtrate is discharged through the filtrate discharge passage, and in the compression step after the filtration step, the diaphragm is expanded from the compression filter plate side to the warming filter plate side for compression, and the filtrate is discharged through the filtrate discharge passage. After the squeezing step, the washing water is supplied from the washing liquid supply passage to blow the sludge in the external sludge supply passage, and then the compressed air is supplied to the filtration chamber to remove the residual filtrate to the outside. To A sludge dewatering method characterized by discharging.