JPS588526A - Running filter cloth type gravity filter machine - Google Patents

Abstract

PURPOSE:To increase the filtering capacity of a filter machine, by taking the inclination angle of the filter cloth of a gravity filter machine so as to bring it close to the same to the friction angle of sludge to be treated. CONSTITUTION:The sludge of a raw liquid is supplied to a sludge receiving tank 2 by a supply machine 1 and, when the inclination angle 1 of a filter 3 is adjusted to an angle near the friction angle of the sludge to be treated, filtering pressure made max. On the other hand, on a filter clotch 3 provided under tension between rolls 7', 7'', 7''' and slide on a porous plate 5, the dehydrated sludge is stayed and drawn out from a sludge liquid level L along with the movement of the filter cloth 3 to be fallen on a belt 11 under the position of the roll 7'' and filtered water is subsequently discharged out of the system by a water collector 16. In addition, after the sludge interposed between an upper belt 10 and a lower belt 11 compressed and dehydrated on a low pressure roll 12, it is moved in a zigzag direction between press rolls 13 to be formed into dehydrated cake and this cake is conveyed out of the system by a conveyor 15.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a traveling furnace cloth type gravity filtration system, and more specifically, to an improvement of a traveling furnace cloth type gravity filtration system mainly used in a belt press type dewatering machine for sludge dewatering. be.

With the spread of sewage systems, the amount of sludge generated at your company is increasing year by year. The sludge is ultimately disposed of by incineration, landfill, or composted, but in any case, the previous dewatering process is important because it greatly affects the economic efficiency of these final treatment processes. The type of dehydrator currently used in the dehydration process is a centrifuge.

There are filter presses, peridot presses, etc., but the belt press type dehydrator is the best overall in terms of energy saving, and for this reason has become rapidly popular recently. Belt press type dewatering machine The sludge sandwiched between two furnace cloths is dehydrated by passing it through multiple press rollers in a zigzag pattern, but as a preliminary step, gravity is used to dehydrate the sludge. There are two gravity filtration parts and a low pressure roller part with low squeezing force.

Of the amount of water dewatered in a belt press type dehydrator, the amount of water dewatered in the two-gravity type dehydrator accounts for 60 to 70% of the total, and the stable dewatering capacity in this part is achieved by the high pressure roller (press roller) part. Pressure dehydration (required cake formation has become one of the important elements.

Conventionally used gravity-type overload structures include those in which sludge is poured flatly onto a running furnace cloth stretched horizontally, and those in which the sludge is poured flatly onto a running furnace cloth stretched at a certain angle; In some cases, a sludge receiving tank is installed on top of the sludge tank, which is connected to the board frame of a hakoya, and overpressure is added to the depth of the sludge to allow the sludge to pass through. The latter has the advantage of increasing the processing capacity per unit area of the P cloth due to the overpressure due to the liquid depth, but in order to increase the filtration pressure due to the liquid depth, the inclination of the furnace cloth is increased and the friction angle of the sludge is increased. If the slope becomes steeper, there is a risk that the sludge will slide down on the furnace cloth, so the actual slope of the furnace cloth is generally small, so there is a drawback that the filtration pressure applied by the liquid depth is small.

The present invention has been made in view of the above points, and its gist is that a running endless furnace cloth is stretched between a plurality of rolls, and the lower end of a frame plate slides on the upper surface of the furnace cloth. A receiving tank for the processing liquid is provided, and the furnace cloth, the roll, and the receiving tank are integrally mounted on a frame.

This is a traveling F-cloth type gravity load overload, characterized in that the upper end of the frame is the fulcrum and the lower end is vertically movable.

The larger the inclination angle of the furnace cloth in the gravity-type p-filtration part of the belt press type dehydrator used for sludge dewatering, the higher the liquid level in the sludge receiving tank, and the higher the filtration pressure due to the liquid depth applied to the furnace cloth.

Since the filtration capacity of the furnace cloth is proportional to the filtration pressure, from this point of view, the larger the inclination angle of the furnace cloth, the more the sludge to be filtered has a coefficient of friction (=friction angle) that differs depending on the sludge as a physical property value. . This friction angle depends on the properties of raw sewage water, the operating conditions of a thickening tank that processes sludge from a settling tank in a sewage treatment plant, and other factors.

If the inclination angle of the furnace cloth is smaller than this friction angle, the dewatered cake can climb up the inside of the sludge receiving tank as the furnace cloth moves. For this reason, in sewage sludge, the friction angle of the sludge is generally around 20 degrees, whereas the angle of inclination of the furnace cloth actually used is often 10 degrees or less for safety reasons. The present invention makes full use of the friction angle of the sludge, uses the maximum angle of inclination just before the dehydrated cake slides down, and increases the filtration pressure to increase the filtration ability of the furnace cloth.

The details of the present invention will be explained below based on Examples.

FIG. 1 is an overall assembly diagram of a belt press type dewatering machine showing one embodiment of the present invention, and FIG. 2 is a diagram showing the arrangement shown in FIG. Reference numeral 6 denotes a belt-shaped oven cloth with a constant width made of synthetic fibers such as nylon, which is stretched endlessly between rolls (7', 7'', 7') and is driven at a constant speed in the direction of the arrow by a drive device (not shown). Under the furnace cloth (3), a perforated smooth stainless steel perforated plate (5) is placed on a roll (75 (7)
The furnace cloth (3) slides on this, so it does not bend due to the sludge liquid chamber.

A sealing material (4) made of neoprene or the like that slides on the furnace cloth is installed in the gap between the frame plate of the sludge receiving tank (2) and the furnace cloth to prevent sludge from leaking.

The above P overload capacity section is integrally mounted on two parallel frames (6), and the upper end of the frames (6) is rotatably supported on the top of the stand (9). . Also, the lower end of the frame is a lifting device (8) driven by an electric motor or the like.
Since it is supported by a telescopic ball (8), the inclination angle of the oven cloth (3) can be adjusted as desired.

The effects of the gravity filtration device configured as described above will be explained next. The undiluted sludge is uniformly mixed by a feeder 1 and supplied to a sludge receiving tank 2.

The properties of sludge generated from sewage treatment plants change depending on the season or the operating conditions of the thickening tank.

Naturally, the friction angle of the sludge also changes. Therefore, the filtration pressure can be maximized by adjusting the inclination angle of the furnace cloth (3) to an angle as close to, but smaller than, the friction angle of the sludge to be treated using the lifting device (8) of the frame (6). .

Dehydrated sludge remains on the furnace cloth (3), which is stretched endlessly between the rolls (7', 7'', 7''') and slides on the perforated plate (5), and the furnace cloth moves. At the same time, the sludge liquid level (pulled out from 0 and falls onto the lower belt (L) at the position of the roll (7). The filtered water is discharged out of the system by the water collector Q→. Upper belt) C1l and The sludge caught between the lower belts (b) is squeezed and dewatered on large-diameter low-pressure rolls (b).

Next, the cake is subjected to high pressure while meandering between small-diameter press rolls (2) and becomes a dehydrated cake, which is then transferred to the upper belt (11).
After being peeled off from the lower belt a and scraped off by Scra'-04, it is carried out of the system by a conveyor (b).

The drive control of the lifting device (8) may be performed at the operator's discretion, but it is also possible to automatically control the tilt angle of the frame (6) to zero by measuring the viscosity, etc., which indirectly indicates the friction angle of the sludge. You can also go there. In the above embodiments, the case of a gravity filter used in a belt press type dehydrator has been described, but the present invention is not limited to this, and the present invention can of course be used in other types of dehydrators.

As is clear from the above explanation, according to the present invention, the filtration capacity of the filter can be increased by setting the inclination angle of the furnace cloth of the gravity filter close to the friction angle of the sludge to be treated, which is extremely important in terms of sludge treatment technology. Beneficial.

[Brief explanation of the drawing]

FIG. 1 is an overall assembly diagram of a gravity filter for a belt press dehydrator showing one embodiment of the present invention, and FIG. 2 is an A of FIG. 1.
-A sectional view. 1: Supply machine, 2: Sludge receiving tank, 3: Furnace cloth, 4: Seal material,
5: Perforated plate, 6: Frame, 7'-7': Roll, 8:
Lifting device, 8: Ball, 9: Stand. 10: Upper belt, 11: Lower belt, 12: Low pressure roll. Bayer, 1i to 16': Water collector. L: sludge liquid level, θ: tilt angle. Patent applicant: Mitsubishi Kakoki Co., Ltd.

Claims (1)

[Claims] A running endless furnace cloth is stretched between a plurality of rolls. A receiving tank for the processing liquid is provided on the upper surface of the furnace cloth, and the lower end of the frame plate slides into contact with the receiving tank, and the furnace cloth, the roll, and the receiving tank are integrally installed on a frame, and the upper end of the frame is used as a fulcrum to move downward. Traveling F right type gravity type, filtration system characterized by the end being able to move up and down.