JPH03268896A - Method for dehydrating screen residue - Google Patents

Abstract

PURPOSE:To improve the sureness of dehydration by assembling a dehydrating stage having a totally enclosed back pressure plate and a full admission transporting stage in accordance with the properties of screen residue and dehydrating it in a screen residue dehydrator. CONSTITUTION:After the back pressure plate 6 is closed and a plunger 32b is reciprocated required times to perform a required dehydration in a screen residue dehydrator 1 provided with a plunger 32 pressure dehydrating means at the lower end of a screen residue dehydrating and transporting duct 5 forming a screen residue discharge opening at the upper end and having a prescribed diameter and a prescribed head, the back pressure plate 6 is opened to deliver the residue to the side of the transporting duct and opening and closing of the back pressure plate 6 and advance of the plunger 32b are combined suitably in accordance with the properties of the screen residue to perform dehydration. In this way, the screen residue can be dehydrated surely.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a screen cleaning and dewatering method in which screen pickled water scraped and removed from waterways of sewage treatment plants, pumping stations, etc. is dehydrated in a duct and transported to a predetermined location. The present invention relates to a method for reliable dehydration in a machine depending on the properties of screen soaking.

[Conventional technology]

Screen pickles conventionally collected from sewage treatment plants and the like have a high moisture content, and it is troublesome for subsequent treatment to put them into a hopper or an incinerator in the collected state. For this reason, it is necessary to dehydrate the collected screen liquid until the moisture content is below a predetermined level. Conventionally, this screen-pickled material is dehydrated using a dehydrator, and the screen-pickled material after dewatering is transported to a hopper or an incinerator using an unloading machine.

In addition, a method of supplying screen liquid into a sealed duct, dehydrating it under pressure, and then pumping it was published in Japanese Patent Publication No. 46-262.
It is disclosed in Publication No. 85.

[Problem to be solved by the invention]

The method of dewatering the screen cleaner using a dehydrator and transporting it to a predetermined location using a conveyor requires a large amount of equipment installation space, and it is difficult to seal the equipment for maintenance and inspection purposes. is an open type. This causes a deterioration of the working environment, such as the scattering of bad odors.

On the other hand, the method of dehydrating under pressure in a sealed duct and transporting it as is is superior. Depending on the properties of the screen residue, it may not be possible to reliably dehydrate it unless the back pressure plate is completely closed.However, in conventional methods, even if a back pressure plate is provided opposite the 1 lange, it is necessary to close it to some extent. However, as the granger moves forward, the screen residue is pressurized and gradually pushed out toward the duct through the open portion of the back pressure plate. For this reason, it is necessary to perform dewatering at a pressure higher than the normal dewatering pressure.

An object of the present invention is to perform reliable dewatering according to the properties of screen residue by a combination of the reciprocating movement of the plunger and the opening and closing of the back pressure plate.

[Means to solve the problem]

The present invention has been made to achieve the above-mentioned object, and includes a pressurized dewatering device mainly equipped with a plunger at the lower end of a duct for conveying screen sludge dewatering having a required diameter and required lift height and having a dewatering screen sludge discharge port formed at the upper end. In a screen sludge dewatering machine equipped with a means for dehydrating screen sludge, the back pressure plate is closed and the plunger is reciprocated once or a required number of times to perform the specified dehydration, and then the back pressure plate is opened and the screen sludge is sent out to the conveying duct to determine its properties. The gist is that the opening and closing of the back pressure plate and the advancement of the plunger are appropriately combined to ensure dehydration.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

Screen sludge collected from sewage treatment plants, pump stations, etc. is conveyed continuously or intermittently, and a screen sludge dewatering unit 11 is placed below the eave end of this conveying means, and a supply system is installed above the dehydrator 1. Hopper 2 is installed. This hopper 2 is provided protrudingly from the upper part of a dehydrating device 3, and this dehydrating device 3 has a cylindrical main body 31 bent at a required angle so that one end faces upward, and is housed in a horizontal part of this main body 31. It consists of a pressurized dehydration means 32 mainly consisting of a plunger,
This pressurized dewatering means 32 uses a hydraulic cylinder 32a, this cylinder 32a is provided with a plunger 32b, and the hopper 2 is disposed above the front end position where this one plunger 32b serves. The outlet at the bottom of this hopper 2 is a little shorter than the stroke of the granger 32b, and this 1 langier 32b
A pressurized dewatering part 4 is provided at a position slightly forward of the position where the is protruded.

Dehydration holes are drilled in this main body 31 from the lower part of the hopper 2 to the lower part of the pressurized dehydration section and beyond this pressurized dehydration position, so that the water contained in the screen residue is removed from the hopper and into the main body. The water is dehydrated from the time it is supplied to the pressurized dehydration section and then drained out of the main body.

The pressurized dehydration section is configured to compress the screen residue using the pressurized dehydration means 32, increase the pressurizing force to a value necessary for dehydration, and maintain the pressurized state for a predetermined period of time even when the piston retreats. This pressurized dehydration section is connected to the dehydration device 3.
It is sandwiched between the main body 3 on the horizontal supply side and the conveying duct 5 on the bent discharge side.

This pressurized dewatering section 4 is comprised of a back pressure plate 6 that swings at a bent portion of the duct 5 or the main body 31 by a pressurizing cylinder 6S, and a cylindrical water draining screen 7.

This drainage screen 7 has flanges 71.71 on both ends as shown in the figure, and these two opposing flanges 71.71.
A large number of screen pars 72 arranged at a predetermined pitch in a broken line annular shape are installed between the flange 71 and the flange 71.
．． 71 is connected with a flange 33 provided on the main body 31 and a flange 51 provided on the duct side with pins or bolts, respectively, so that it can be easily attached and detached during cleaning.

In addition, as shown in FIG. 2, the duct 5 for conveying the dewatered screen residue can have a cross-sectional shape of various shapes such as a cylindrical shape, a rectangular shape, a semicircular shape, etc., and one side of the duct is open. The duct 115b may be attached to the duct, or the duct may be divided into two parts to open the inside of the duct for easy cleaning. Furthermore, whether the duct 5 has the same diameter from its starting end to its terminal end, or whether it has a tapered shape with a larger diameter at its terminal end is appropriately determined depending on the conveyance and lift distance.

In order to transport dehydrated screen pickles in the duct at low*S, a low-friction material may be pasted or coated inside the duct.

A plunger 32 is placed at a fixed position at the rear end of the screen soaking inlet 3H formed in the lower end of the hopper of the dehydrator main body 31 and the continuous part.
A sensor S, such as a proximity switch, for detecting a state in which the main body 31 is stopped and on standby is installed by cutting out a part of the upper part of the main body 31, and the sensor S is covered with a cover ○ if necessary. The completion of compression is known from the detection signal from this sensor S.

As shown in FIG. 4, the hydraulic circuit of the cylinder 32 for pressurized dewatering and the cylinder 6S for back pressure is connected to a tank T, a hydraulic pump P, and a switching valve Vl.

(2) Piped to each cylinder via 2.

In the screen residue dewatering machine configured as described above, the plunger 32b normally moves forward and backward at regular intervals to remove the screen waste from the hopper into the dewatering device 3. Correspondingly, the back pressure plate 6 is opened and closed to perform dehydration and extrusion. The forward and backward speed of this Granger is fast at the beginning of forward movement, slow near the end,
The dewatering effect can be improved by changing the speed, such as increasing the speed when reversing.

However, due to the nature of screen soaking, the back pressure plate may be closed.
In addition, it is necessary to move the plunger back and forth twice to increase the squeezing force for dewatering.

In such a case, the back pressure plate 6 may be completely closed and the plunger moved forward to perform the first pressurized dehydration, or the plunger may be moved back with the back pressure plate closed and the second pressurized dehydration performed. . By repeating this action at least twice, the number of pressurization increases, the pressure increases, and dehydration can be performed more reliably, and the compression chamber is filled to capacity, allowing the desired dehydration to be performed and the plunger to be completely fixed. When it no longer protrudes to this position, the sensor S detects that the dehydration is complete.

Then, by opening the back pressure plate and pushing the plunger forward, the screened dehydrated residue is sent out to the conveyance duct side.

Note that the opening/closing operation of the back pressure plate and the forward operation of the plunger are coordinated as appropriate depending on the properties of the screen residue.
At the time of delivery, the back pressure plate may not be completely opened, but may be left half-open and the screen pickled material may be sent out to the duct side under a certain degree of pressure.

In addition, the fullness of the compression chamber can be detected in advance by the number of reciprocations of the plunger, or by the pressure switch PS installed in the hydraulic circuit.
In addition, it is possible to fully open the back pressure plate during the dewatering process and fully open the back pressure plate during the transport process, or to apply strong pressure or weak pressure by adjusting the opening/closing degree of the back pressure plate. .

〔Effect of the invention〕

According to the present invention, a dehydration step in which the back pressure plate is fully closed;
Since the dewatering process is carried out in appropriate combinations with the conveying step in which the screen is fully opened, depending on the properties of the screen pickling, there is an advantage that dehydration can be carried out reliably.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional front view of the screen residue dehydrator of the present invention, Figure 2
The figure is an overall external view, FIG. 3 is a sectional view showing different embodiments of the duct cross section, and FIG. 4 is a hydraulic circuit diagram of the screen residue dehydrator. 2 is a hopper, 3 is a dewatering device, 3H is an inlet, 31 is a main body, 32a is a hydraulic cylinder, 32b is a plunger,
4 is the pressurized dewatering section, 5 is the duct, 5R is the bent part, 6 is the back pressure plate, 7 is the water drainage screen, S is the sensor

Claims (1)

[Claims] (1) In a screen sludge dehydrator equipped with pressurized dehydration means mainly consisting of a plunger at the lower end of a screen sludge dewatering conveying duct having a required diameter and required lift with a dewatered screen sludge discharge port formed at the upper end, a back pressure plate is used. After closing the screen and reciprocating the plunger once or the required number of times to perform the specified dehydration, the back pressure plate is opened and the screen residue is sent to the conveying duct side, and the screen residue is opened and closed and the plunger is moved forward depending on its properties. A method for dehydrating screen sludge, which is characterized in that the dehydration of screen sludge is ensured by appropriately combining the following.