JPH1033913A - Rotary filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary filter scraping deposited cake to continuously and stably perform solid-liquid separation for a long time without stopping. SOLUTION: In a rotary filter equipped with a cylindrical pressure container 1 having a raw water 2 and a conc. soln. outlet 3 and providing a stirrer 6 fluidizing a concn. soln., a pressure gauge 11 and the communication port communicating with a filtrate taking-out port 7 in the container 1 and housing a plurality of filter members 4, 5 partially equipped with a rotatable mechanism, a plurality of the filter members 4, 5 have a cylindrical shape and are arranged in a concentric circular state so as to be adjacent to each other at a predetermined interval. The predetermined interval is set so that the wet cake formed to the surface of the filter members is forcibly scraped to the cake thickness with a specific range by always rotating one filter member 4 and, when the upper limit speed of the pressure gauge 11 becomes larger than a specific value, the number of rotation of the stirrer and that of the rotary filter member 4 can be altered to a specific range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotary filtration device, and more particularly to a rotary filtration device for filtering and concentrating suspension or sludge generated in a wastewater treatment step, a sludge treatment step, various production steps, and the like.

[0002]

2. Description of the Related Art Conventionally, in a membrane separation device using a microfiltration membrane, an ultrafiltration membrane, or the like, when a sludge or a suspension in wastewater is removed, a cake layer is formed on a filtration surface as filtration proceeds. ,
There was a tendency to increase the filtration resistance by clogging the filtration surface. As a method of peeling the cake layer, there have been many methods of peeling by a water flow such as a turbulent flow or a vortex generated by a rotating motion of a stirrer or a filter itself, and a method of forcibly peeling by a blade or a scraper. However, in the cake peeling method using a water flow, the strength of the water flow inside the device often tends to be uneven, and it is difficult to accurately control the cake thickness of the entire filtration membrane. Was often reduced. In the cake peeling method by forcible peeling, the distance between the scraping body and the membrane is too small to damage the membrane, or if the operation is performed for a long time, the remaining cake is gradually compacted and the filtration resistance gradually increases. There were many. In either case, backwashing or the like is performed to reduce the filtration resistance, and there is a problem that the apparatus needs to be stopped for a long time to peel the cake.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and eliminates the need to stop the apparatus by backwashing or the like. An object of the present invention is to provide a rotary filtration device that enables efficient solid-liquid separation.

[0004]

According to the present invention, there is provided a cylindrical pressure vessel having a raw water inlet capable of supplying a suspension and a concentrated liquid outlet capable of extracting a concentrated liquid. Inside, there is a stirrer for flowing the concentrated liquid inside, a pressure gauge that can transmit the pressure value inside the container to the outside by a signal, and a communication port that communicates with the outlet of the filtrate, and some In a rotary filtration device containing a plurality of filter bodies provided with a rotatable mechanism, the plurality of filter bodies are arranged cylindrically and concentrically adjacent to each other at predetermined intervals, and the predetermined intervals are adjacent to each other. This is the interval at which at least one of the filter media to be rotated constantly rotates, so that the wet cake formed on the surface of the filter media is forcibly shaved to a cake thickness within a specific range without thickening, and furthermore, the shaved residue remains. Cake is compacted If the over-resistance increases and the upper limit speed of the pressure gauge exceeds a specific value, the rotation speed of each of the stirrer and the rotary filter can be changed to a specific range so that most of the cake layer is separated. Means. In the above-mentioned device, it is preferable that the number of revolutions be changed automatically.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a plurality of rotary filters,
A pressure gauge capable of outputting a signal to the outside and a stirrer for generating a large water flow are provided in the apparatus at the same time so that the cake thickness is forcibly peeled in a range of 3 to 9 mm. When the pressure increase speed becomes 2-3 times the normal, or at regular time intervals, the number of rotations of the stirrer and the rotary filter is respectively increased for a predetermined time, for example, the number of rotations is 1.5 times or more, respectively. It is a rotary filtration device that allows most of the compacted cake to be peeled off by, for example, being operated while being raised for several minutes, thereby stably performing a long-time continuous concentration treatment. Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a main part of a rotary filtration device according to an example of the present invention.

In FIG. 1, reference numeral 1 denotes a closed cylindrical container,
A raw water supply port 2 capable of supplying a suspension is provided at a lower portion, and a concentrate outlet 3 is provided at at least one position at an upper portion. The separation membrane 9 communicates with the filtrate outlet 7 in the container 1.
Is fixed on the outer surface of the cylindrical rotary filter 4 and the fixed filter 5 so that the gap at the upper portion of the membrane surface is 9 mm. Further, an adjustable blade 10 for scraping the cake layer formed on the membrane surface to 3 to 9 mm is provided inside the container 1 and the rotary filter, and the flow in the container is provided at the bottom of the container 1. A stirrer 6 for controlling is provided. The rotary filter and the stirrer 6, which are connected to separate driving devices (not shown), are sealed by a shaft sealing device 8, and have a structure that can withstand high pressure and high rotation for a long time. There is a mechanism that can be controlled by an inverter so that the rotation speed can be changed to a predetermined set value when the consolidation cake is peeled off. 11 is a pressure gauge. For example, when the tank pressure rises to a certain pressure, the sludge valve is set to open for a certain period of time, and when the interval until the next time the sludge valve opens becomes a specific value or less, the inverter rotates the rotating speed of the stirrer and the rotary filter. , A sequence that rises to a specific value for a certain period of time can be incorporated.

[0007]

The present invention will be described below in more detail with reference to examples. Example 1 The rotary filtration device of the present invention shown in FIG. 1 was used as a concentrator as follows. Effective membrane area for separation membrane
Using a 5 m ² microfiltration membrane, SS concentration 0.8-12.0
g / l of the inorganic suspension was supplied at an average flow rate of 125 l / h, and the continuous concentration operation was performed for about 3 months. In the ordinary filtration step, the rotational speed of the rotary filter is set to 170 rpm, the rotational speed of the stirrer is set to 90 rpm, and the rotational speed of the rotary filter is set to 310 rpm every 8 hours or every time the pressure increase speed becomes 2.5 times or more of the normal speed. An operation method of changing the rotation speed of the stirrer to 150 rpm for 5 minutes was adopted. In addition, the test by the conventional example was also performed. As a conventional example, the same apparatus as in the example was used except that a blade for cutting the cake thickness to 15 mm was attached.

Table 1 shows the processing results.

[Table 1]

Although there was no difference between the treatment speed and the treated water SS concentration in the results of the embodiment and the conventional example, the concentrated sludge concentration was 132 (g / l) on average in the embodiment, In the conventional example, the average was 85 (g / l). This is because, in the conventional example, since the cake remaining after shaving has a thickness of 15 mm, the filtration resistance is large and the pressure rises quickly, so that the concentration does not proceed. Regarding the continuous operation time, in the example, the stable concentration treatment was still possible even after 90 days, whereas in the conventional example, the pressure increased sharply on the 26th day. As in the example, cake rotation was attempted by increasing the rotation speed of the rotary filter and the stirrer,
No improvement was seen. It can be seen that there is a delicate balance between the cake peeling phenomenon due to an increase in the number of rotations of the rotary filter and the stirrer and the cake thickness. By controlling the cake thickness within a certain range and changing the rotation speed of the rotary filter having a predetermined capacity and the number of rotations of the stirrer under certain conditions, a long-time continuous concentration operation can be performed.

[0010]

According to the present invention, when the cake thickness is within a certain range, when the rate of rise of the pressure gauge becomes larger than a specific value, the number of rotations of the rotary filter and the stirrer is changed under a certain condition, whereby the adhered cake is removed. It was possible to operate continuously and stably for a long time without peeling and stopping the device.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of a rotary filtration device according to an example of the present invention.

[Explanation of symbols]

1: cylindrical container, 2: raw water supply port, 3: concentrated liquid discharge port,
4: rotating filter, 5: fixed filter, 6: stirrer, 7: filtrate outlet, 8: shaft sealing device, 9: separation membrane, 10: blade with adjustment function, 11: pressure gauge,

Claims (2)

[Claims] 1. A cylindrical pressure vessel having a raw water inlet capable of supplying a suspension and a concentrate outlet capable of withdrawing a concentrate, a stirrer for flowing a concentrate therein, and a container. A pressure gauge capable of transmitting an internal pressure value to the outside by a signal and a rotation housing a plurality of filtration bodies having a communication port that communicates with a filtrate extraction port and having a partially rotatable mechanism. In the filtration device, the plurality of filter bodies are arranged so as to be cylindrical and concentrically adjacent to each other at a predetermined interval, and at least one of the filter bodies adjacent to the predetermined interval constantly rotates, This is the interval at which the wet cake formed on the surface of the filter body is forcibly cut to a cake thickness within a specific range without thickening, and the remaining cake is compacted to increase the filtration resistance, and the upper limit speed of the pressure gauge Is greater than a certain value A rotary filtration device comprising: means for changing the number of rotations of each of a stirrer and a rotary filter to a specific range so that most of the cake layer is peeled off when it becomes hard. 2. The rotary filter according to claim 1, wherein the means for changing the rotation speed is a means for automatically changing the rotation speed.