JPS62207599A - Belt press type dehydrator - Google Patents

Abstract

PURPOSE:To improve the efficiency in dehydrating by providing the 1st filter cloth belt consisting of a monofilament filter cloth at a gravity dehydrating part and by arranging a pair of the 2nd filter cloth belts having a felt filter cloth at the squeezing dehydrating part of the downstream. CONSTITUTION:An endless travelable monofilament filter cloth 1 is provided at a gravity dehydrating part (a) via a roller 5 and roller 6, and a pair of felt filter cloths 2, 3 traveling by being suspended on roller groups 7-14 are arranged as well. A muddy body 4 is first fed on the monofilament filter cloth 1, dehydrated with gravity while being transferred on the gravity dehydrating part (a), then subjected to a forced dehydration by the felt filter cloths 2, 3 at a predehydrating part (b) and squeezing dehydrating part (c). A sufficient dehydration is performed by the filter cloth 1 of the gravity dehydrating part (a) and the clogging of the filter cloth can be prevented because of the use of the felt filter cloths 2, 3. Consequently, the dehydration efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a belt press type dehydrator for dewatering materials to be treated such as sludge generated during the treatment of sewage, human waste, industrial wastewater, etc.

[Conventional technology]

Regarding belt press type dehydrators, for example,
The one disclosed in Japanese Patent No. 21878 is known.

This will be outlined with reference to FIG.

In Figure 4, a mud 4k OJ is placed between a pair of filter cloth helmets 141.
43 is supplied, and the filter cloth belt 41. 42 travels, the sludge undergoes filtration H using only its own weight; 2. The space between the gravity dewatering section e where water is carried out and the filter cloth belts 41 and 42 is gradually narrowed in a pattern, and the pressure acting on the sludge 43 is reduced. The mud is sent to the preliminary dehydration section f, which is gradually increased, and then to the compression dehydration section g, where dewatering progresses by the squeezing force generated by the tension of the filter cloth belts 4 and 42 wound around rollers. 43 is dehydrated, and the dehydrated cake is peeled off once it reaches the cake i/. In the figure, 44 is a filtrate receiver, and the arrow indicates the direction of travel of the filter cloth belt.

[Problem that the invention seeks to solve]

However, depending on the nature of the sludge, the dehydrated cake gets stuck in the filter cloth, which often causes the cake to peel off from the filter cloth. Furthermore, in recent years, there has been a tendency to increase the pressure in the pressing and dehydrating step in order to reduce the water content of the dehydrated cake, and when the pressing force is increased, the above-mentioned deterioration of peelability becomes even more remarkable. Due to such deterioration in cake peelability, the solids remaining in the filter 4I are not collected and washed first)71
It returns to the water treatment process with ice, and the solids recovery rate is 1ζ1.
In addition, the cleaning of the filter cloth was incomplete and IIaa+ was 7.
! f! ! It gets clogged in the gap between II.

- In general, the filter cloth used in belt press dehydrators is called a monofilament filter cloth, as shown in Fig. 3, and is a monofilament cloth made of polyester or the like with unbraided straw weft [1ij-<hM]. 30 and warp; [, nofilament 3
It is woven from scratch, and has a silk structure with a gradient of 11t. , lI
This caused worsening of detachment.

A recently developed felt filter cloth using a nylon web as shown in FIG.
and a multifilament 26 of a plurality of weft threads,
Since the surface of the filter cloth is covered with the dense felt layer I consisting of the web 27, even when dewatering is performed with high squeezing force, the cake is difficult to dig into the filter cloth, and the cake can be easily peeled off.

However, as a prior art, a filter cloth was used for filtering.
When I operated the 52-water machine, I found that although the cake peelability was good, the speed of water removal in the gravity dewatering section gradually decreased, and the rollers at the back where the natural dehydration in the gravity dewatering section was insufficient. Because the cloth is squeezed by the cloth, there is a problem in that the mud (19) sticks out from the cloth. When I measured the air permeability of the filter cloth under these conditions, it was about 175, which was the original value.
It was found that the value had decreased to about 1710.

This reduction in the permeation rate of the felt filter cloth, i.e.
It was found that the decrease in air permeability occurred mainly in the gravity dewatering section. In the gravity dewatering section, the mud with a water content of about 98-99% is converted to natural 112 water by the action of gravity, with a water content of about 9%.
It is dehydrated to a semi-solid slurry of 0 to 95%,
Most of the water that should be removed during the entire dehydration process including the high-pressure dehydration section (corresponding to about 80 to 90%) is removed in this gravity dehydration section. At this time, the fine solids in the slurry (
SS (hereinafter referred to as SS) enters the felt filter cloth where the threads overlap (hereinafter referred to as tissue point), and the SS that has entered this tissue point is removed by the usual filter cloth cleaning method. It is difficult to imagine that this makes the ventilation claws of the Sogold filter cloth even lower.

The purpose of this invention is to solve the above-mentioned problems (4) and (2) to improve the water permeation rate of the gravity dehydration section (filtration function does not deteriorate even over a long period of time), and to improve the natural flow rate of the gravity dehydration section. Belt press type dehydration that completely dewaters, does not clog the filter cloth or deteriorate peelability in the high-pressure dehydration section, has a high solids recovery rate, and can reduce the moisture content of the cake. The goal is to provide opportunities.

[Means for solving problems]

The present invention is configured as follows in order to solve the above problems and achieve the object of -1.2.

That is, the present invention provides a first filter cloth made of monofilament filter cloth that is installed to be able to run endlessly and that constitutes a gravity dewatering section.
[1,-:) is installed downstream of the filter cloth belt and the first filter cloth belt to be able to run endlessly, and constitutes a BV-shaped preliminary dehydration section and a compression dehydration section provided downstream of the preliminary dehydration section. A pair of second filter cloth belts, at least one of which is made of felt filter cloth, are provided, and the general delivery rate of four rivers to the first) 1G cloth is set to be faster than that of the second i1@ cloth belt. Regarding the belt press type dehydrator with 4'ff1l, to explain in more detail, the conveyance speed of the first filter cloth filter 1 is about 2 to 8 times that of the 221st: i + filter cloth 1. The speed is adjusted so that the filter cloth belt 1 and the second filter cloth belt 1 and 1 are provided with means for detecting a thicker accumulation of the material to be treated on the first filter cloth belt 1 and the second filter cloth belt.
First iIa cloth shell 1 and i; said second filter cloth shell 1-
In order to control the accumulation of material to be processed in 1- within a predetermined range, the first filter cloth 1. ! This invention relates to a belt press type dehydrator characterized in that it is constructed in such a way that the conveyance speed of the second filter cloth belt and the second filter cloth belt can be controlled.

[Effect]

Since the second invention is configured as described above, it works as follows. That is, a monofilament filter cloth is provided as the first filter cloth belt of the gravity dewatering section through which most of the total water to be removed from the slurry (approximately 80 to 90%) passes through, and the monofilament filter cloth #For the filter cloth belt made of cloth, [1
The water permeation rate in the gravity dehydration section, −), i[j No lowering of the spiracles occurs. Therefore, natural dewatering in the gravity dewatering section is completely performed, the slurry loses its fluidity and becomes semi-solid, and the phenomenon of cake being filtered out during the press dehydration process does not occur.

In addition, there is a preliminary dewatering section that performs forced +11Th water and a press 11
The first xylem has at least a second filter cloth heel 1 made of felt filter cloth, which is independent of the gravity dehydration section mentioned above.
h L7, even if dewatering is performed with high pressing force, the slurry will not dig into the holes of the filter cloth belt, so the peelability of the cake will not deteriorate. Furthermore, the felt filter cloth retains a small amount of water in the felt layer, forming a thin film of water, which improves the cake removal properties. Furthermore, in the belt press type JB2 water (1) according to the present invention, even when high-pressure dehydration is performed, the cake releasability does not deteriorate.

Further, depending on the conveyance speed of each of the filter cloth belts, the thickness of the mud on the filter cloth belt is thinner in the 0:1 tonnage dewatering section, and becomes thicker in the preliminary dewatering section.

While the gravity dewatering section naturally dehydrates the water in the gutter, in order to increase the permeation rate of the filtrate through the gutter, it is better to have a faster conveyance speed of the monofilament filter cloth, and also to have a thinner boiling layer thickness. However, the filtered air IN is small.

-・In the pressing and dewatering section, in order for the pressing force to be effectively transmitted to the dehydrated cake, the dehydration time is long, and the conveyance speed of the filter cloth is preferably slow. Further, the thicker the dehydration game 4, the better the cake peelability.

In order to achieve the above, means for detecting the accumulated thickness of sludge is provided near the outlet of the gravity dewatering section and near the entrance of the preliminary dewatering section, and the filter cloth belt of the gravity dewatering section is conveyed. speed V, and a pair of filter cloths in the pre-dehydration section 1-
Means is provided to automatically change the general delivery level v2.

As a specific example, if the accumulated thickness of sludge near the outlet of the gravity dewatering section is within the range of approximately 1 to 4 s, and the thickness of the sludge near the entrance of the preliminary dewatering section is The thickness of
The first
The first general feed +yv of the filter 41 and the four rivers +mu and the conveyance speed V2 of the second filter cloth belt are combined subzuru 51.2-, and in this case, the conveyance speed v1 is approximately equal to the speed V2. This can be achieved by controlling each time so that it is within the range of 2 to 8 times.

〔Example〕

Hereinafter, with reference to the drawings, this invention will be described on the 3rd floor, Ruhe 71 River,
An example of a press type dehydrator will be described in detail.

In FIG. 1, a pair of filter cloth belts arranged to be able to run endlessly by roller groups 7 to 14 are connected to one filter 41 that is installed to be able to run endlessly on rollers 5 and Ll 6. It is shown. The filter cloth belt running on the +1-ra 5 and the roller 6 is composed of monofilament 1 filter cloth 1 as shown in FIG. Also, m
The filter cloth belt that runs around the l-ra groups 7 to 14 is
Felt filter cloth 2 and felt l-'d as shown in FIG.
It is composed of a cloth 3. The felt filter cloth 2 is located on one side, and the felt filter cloth 3 is installed below.

Polymer flocculant in a flocculation tank (not shown)! : mixed kI
J Treatment of water, human waste, industrial wastewater, etc. T Sludge generated in culms 4C11, monoph, f lamen 1 - filter cloth 1 t! ; While being fed through the gravity dewatering section a, it is dehydrated by the action of gravity and processed into a semi-solid state with a moisture content of approximately 90 to 95%. At this time, most of the water that should be removed from the dehydrator passes through the monofilament filter cloth 1, and the filter cloth receiver passes through the monofilament filter cloth 1.
It is collected at 8. For this reason, it is important to ensure the filtrate permeation V in the gravity dewatering section a, and a filter cloth woven with relatively thick jet fibers, that is, monofilament 1, has a higher water permeation W.
It is also easy to clean. In addition, the thickness of accumulated mud is also thin.
However, since there is little filtration resistance due to mud, the filter cloth belt can be used at relatively high running speeds (approximately 0.5 to 5 tn/m:n).
It is set to be sent to the general public.

The slurry 4 then falls onto the felt filter cloth 3. In the preliminary dewatering section where the gap between the pair of felt filter cloths 2 and 3 is gradually narrowed in a wedge shape, the slurry 4 is squeezed by the pair of felt filter cloths 2 and 3. Furthermore, the river filter cloth 2 for phenol and the felt filter cloth 3 are compressed 1'l rough and compressed 1'□I- in the compression dewatering section C.
The slurry 4 is forcibly dehydrated by the 1i41 tension and the 1: , , -c generation 4゛i111 no1 surface pressure. De-throat or complete r1 eight mud 4) Thing 4 (
The dehydrated cake) is carried out to the dehydrator I.

Further, the mud 4 that has adhered to the felt filter cloth 2 and the felt filter cloth 3 is peeled off from the felt filter cloth 2 and the felt filter cloth 3 by the scraper 16 and the scraper I7.

Furthermore, the amount of water removed from the slurry in the preliminary dewatering section and the pressing dewatering section C is 2! #Collected in the liquid receiver 19 and removed from the dehydrator.

According to the present invention, water is removed from the felt filter in the preliminary dewatering section and press dewatering section C, where the squeezing force due to filter cloth tension is applied to the slurry 4. It passes through the cloth 2, the felt 1, and the filter cloth 3 and is discharged.

The surface of felt filter cloth No. 2 and 3 is covered with a dense felt layer, which prevents muddy substances from digging into the holes of the cloth.
Cake peeling 1viI111F is also very good.

Although an actual example of the belt press type dehydrator according to the present invention has been described in detail, the present invention is not limited to these details. It is often observed that #I occurs only in one of the two, but in such cases, #I
A similar effect can be obtained even if only the filter cloth belt that is difficult to separate is made of felt filter cloth, and the other filter cloth belt is made of monofilament filter cloth.

It has been observed that in terms of cake removability, the thicker the final dehydrated cake is, the better it is in general. Final dehydrated cake thickness
If the thickness is less than about 5 mm, removability may be poor even if a felt filter cloth is used. The cake thickness of the final dehydrated cake is
Although it varies depending on the properties of the cake (moisture content and density), pressing pressure, etc., it is about 172 to 175 times the accumulated thickness t2 of the slurry near the entrance 1 of the preliminary dewatering section. Therefore, in order to obtain a final dewatered cake with a thickness of about 5 or more, the accumulated thickness of mud in the preliminary dewatering section is L2L.
;t, at least in the range of about 10 to 25 yen, preferably
Approximately 5mm or more is required.

On the other hand, if the mud in the preliminary dewatering section becomes too thick,
At the culm, the groin protrudes and becomes 2. There are 100 cases of this protrusion.

From the above, the game and 11v of the preliminary dehydration section is approximately 2
It is preferable that the distance be within the range of 0.0 mm or more and approximately 5 mm or less. On the other hand, if the accumulated thickness tl of mud near the outlet of the gravity dewatering section is about 5 mm or less, the processing speed and solids recovery rate will be significantly reduced. In addition, if the accumulated thickness tl of the muddy material is about 5 mm or more, the filtrate permeation rate due to the filtration resistance of the accumulated material will decrease significantly, so about] Om
■It is desirable that the following two points be within the range of approximately 4Q mwa or less.

In order for a belt press type dehydrator to satisfy the operating conditions as described below, the conveying speed of the filter cloth belt made of monofilament I/filter cloth in the gravity dehydration section must be adjusted to the same level as that in the preliminary dehydration section and the compression dehydration section. It is desirable that the conveying speed of the pair of filter cloth belts be within a range of at least about twice or more and at most about eight times or less.

Further, in the belt press type dehydrator according to the present invention,
The monofilament filter cloth is provided with a means for automatically detecting the accumulated thickness tl of mud, the filter cloth belt 3 is provided with means for automatically detecting the accumulated thickness t2 of mud, and further , a means is provided for automatically changing the general delivery degree (1) of the ten-filament cloth 1 and the conveyance speed (2) of the filter cloth belts (2 and 3), at least one of which is a felt 1-filter cloth. Accumulation thickness of objects 1. If it is automated so that the conveyance speed ■1 and conveyance speed ■2 can be set to the above-mentioned values based on the signals of the accumulation thickness t2 and the accumulation thickness t2, it is possible to save labor in operating the press type dewatering machine. .

As a means for measuring the accumulated thickness tl and accumulated thickness t2 of mud, for example, in addition to the method of measuring and detecting the reflection time of ultrasonic waves, any of the electrode method, capacitance method, photoelectric method, etc. It may be a method. In addition, as means for changing the general delivery degree (1) and conveyance speed (V2), in addition to the method of changing speed using a small E-motor (pilot motor), any device such as an inverter or (1) S motor may be used. Of course.

〔Effect of the invention〕

Since the belt press type sludge dewatering machine according to the present invention has the above-mentioned structure, it has the following effects. Of course, monofilament filter cloth is installed as the filter cloth in the gravity dewatering section through which most of the total water to be removed (approximately 80 to 90%) passes through the sludge or copper, so the water in the gravity dewatering section is The permeation rate does not decrease over a long period of time, that is, the permeability does not decrease, natural dewatering in the gravity dewatering section is completed, and the slurry loses its fluidity and becomes semi-solid. Next, the slurry is compressed and dehydrated, so that the belt press type dehydrator can be stably operated without causing any cake to protrude. In addition, felt filter cloth is installed in the process where mud is forcibly dehydrated in the preliminary dewatering section and press dehydration section, so there is no clogging of the filter cloth or deterioration of peelability, and the solids recovery rate is is high, and the cake moisture content of the resulting cake is also low. Furthermore, in the felt filter cloth, the slight amount of water retained in the felt layer becomes a thin film of water, so even when high-pressure dehydration is performed, there is no deterioration in cake peelability, making the cake peelability even better. .

In addition, the transport speed of the Sennofilamen I filter cloth in the gravity dewatering process is approximately 2 to 8 times that of the felt filter cloth in the forced dewatering process.
Therefore, in the natural dewatering process in the gravity dewatering section, the filtration resistance is small because the accumulated thickness of the mud is small, so a sufficient water permeation rate can be obtained. On the other hand, in the forced dehydration step in the preliminary dehydration section and the press dehydration section, the cake thickness is increased, so the squeezing force is effectively transmitted, the cake water content is low F, and the peelability of the cake is also improved.

In addition, detection means for detecting the accumulated thickness of sludge and means for adjusting the conveyance speed of each filter cloth belt are provided near the outlet of the gravity dehydration section and near the entrance of the preliminary dewatering section, and these detection means are provided. and by associated control of the regulating means.
Since the operation of the belt press type dehydrator can be controlled unattended under optimal conditions, it is possible to achieve various extremely effective effects, such as being able to save labor in operating the belt press type dehydrator. .

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an embodiment of the belt press type dehydrator according to the present invention, and Fig. 21-1 shows the Sol 1 +; J6 fabric used in the April press type dehydrator shown in Fig. 1. 3 is a sectional view showing the monofilament filter cloth used in the Herts type 1112 water machine shown in Fig. 1, and Fig. 4 is a schematic diagram showing an example of a conventional Hert press type dehydrator. be. 1 - Monofilament filter cloth, 2.3 Felt filter cloth, 4 - Sludge, 5.6 Roller in gravity dewatering section, 7.8 - Roller for one-press dewatering, 9.1
0. l 1,12. l 3. l 4-4: J-La, 15
, 16. 17--Scraper, 18.19-Filtrate receiver, 25-Warp monofilament, 26--
-Weft multifilament, 27 web, 30-
---One weft monofilament, 31-Warp monofilament, L-Felt layer, V,, V2--One conveying speed, a-Gravity dewatering section, b--Preliminary dewatering section, c--1 compression dewatering section, (1 cake peeling section, t
, , t 2 - Accumulation thickness.

Claims (4)

[Claims] (1) A first filter cloth belt made of monofilament filter cloth that is installed to be able to run endlessly and constitute one gravity dehydration section, and a wedge-shaped preliminary dewatering section that is installed to be able to run endlessly downstream of the first filter cloth belt. and a pair of second filter cloth belts, at least one of which constitutes a compression dehydration section provided downstream of the preliminary dewatering section, and which is made of felt filter cloth, and the conveyance speed of the first filter cloth belt is set to the second filter cloth belt. A belt press type dehydrator characterized by being set to be faster than a belt type dehydrator. (2) The belt according to claim 1, wherein the conveying speed of the first filter cloth belt can be adjusted to be about 2 to 8 times that of the second filter cloth belt. Press type dehydrator. (3) The belt according to claim 1, further comprising means for detecting the accumulated thickness of the processed material on the first filter cloth belt and the second filter cloth belt. Press type dehydrator. (4) Conveyance of the first filter cloth belt and the second filter cloth belt in order to control the accumulated thickness of the processed material on the first filter cloth belt and the second filter cloth belt within a predetermined range. The belt press type dewatering machine according to claim 1, wherein the belt press type dewatering machine is configured so that the speed can be controlled.