JPH02214600A - Screenings dehydrator - Google Patents

Abstract

PURPOSE:To improve the efficiency of the dehydrator by providing a pressure dehydrating means with the inner diameter locally reduced in the vicinity of the forward stroke end of a pressure supply means in a screenings dehydrating and conveying duct, increasing the residue supply pressure to a value necessary for dehydration and then reducing the flow resistance in the duct after the residue is passed. CONSTITUTION:The screenings supplied to a hopper 2 is moved in a conveying duct 5 by a piston 3. The pressure dehydrating means 4 with the inner diameter locally reduced is provided in the vicinity of the forward stroke end of the piston 3. The length of the throttled part is made almost equal to the stroke of the piston 3, and dehydrating holes are formed on its periphery. The screenings extruded by the piston 3 is pressed into the pressure dehydrating means 4, dehydrated, retained during the backward stroke of the piston 3 and effectively dehydrated. The screenings dehydrated by the pressure of the succeeding residue due to the reciprocation is extruded from the throttled part and passed through the duct 5 while the flow resistance is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a system for transporting sludge (screen sludge) pumped up and removed from waterways of sewage treatment plants, pumping stations, etc. to a predetermined location while dewatering it in a duct. This is used in a sushi residue dehydrator.

[Conventional technology]

Conventionally, wastewater collected from sewage treatment plants has a high moisture content,
Feeding the collected waste into a hopper or into an incinerator requires a lot of effort for post-processing. For this reason, it is necessary to dehydrate the collected residue until the moisture content is below a predetermined level. Conventionally, this sludge is dehydrated using a dehydrator, and the sludge after dewatering is transported to a hopper or an incinerator using a transporter.

Furthermore, Japanese Patent Publication No. 46-26285 discloses a method of pressure feeding inside a sealed cylinder (duct).

[Problem to be solved by the invention]

The method of dewatering the residue using a dehydrator and then transporting it to a predetermined location using a conveyor requires a large space for installing the equipment, and it is difficult for maintenance and inspection to seal the equipment, so it is difficult to open it. Because it is a molded type, it causes a deterioration of the working environment such as the scattering of bad odors.

Furthermore, large resistance occurs between the inside surface of the duct and the residue in all conveyance processes other than dehydration, and strong pumping force is required to convey the residue, which increases the size of the equipment, especially the pressure-feeding device, and increases running costs. There is a drawback.

The present invention aims to obtain the internal pressure necessary for dehydration only in the dewatering process, and to enable high-lift transport with low resistance in the transport process.

[Means to solve the problem]

In a duct for transporting residue dewatering having a required diameter and a required lift, the upper end serves as a dehydration and residue discharge port, and the lower end is equipped with means for supplying residue under pressure. It is equipped with a specially designed pressurized dewatering means to increase the feed pressure of the residue during compression to a value necessary for dehydration, and to reduce the flow resistance within the main body after passing through the pressurized dewatering means.

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

In the figure, reference numeral 1 denotes a conveying means such as a conveyor that continuously or intermittently conveys residue collected from sewage treatment plants, pump stations, etc., and a hopper 2 for supplying residue is located at the lower end of this conveying means I. Arrange. This hopper 2 is provided in a protruding manner on the upper part of a dehydrating device 3, and this dehydrating device 3 has a cylindrical main body 3 bent at a required angle so that one end faces upward.
1, and a carrying-out means 32 housed in the horizontal part of this main body 31, and this carrying-out means 32 uses a screw conveyor 33 in addition to a hydraulic cylinder 32a.
Is there a piston 32bf? : The hopper 2 is provided above the forward position of the tip position where the piston 32b is sunk.
will be placed. The outlet at the lower part of the hopper 2 is made slightly shorter than the stroke of the piston 32b, and the pressurized dewatering means 4 is provided in the main body at a position slightly forward of the position where the piston 32b protrudes. A dehydration hole 3H is bored in the main body 31 from the lower part of the hopper 2 to the lower part of the pressurized dehydration means 4 and a position past this pressurized dehydration position, so that the water contained in the residue is removed from the inside of the hopper. The water is dehydrated from the time it is supplied into the main body until it is dehydrated under pressure, and then drained out of the main body.

The pressurized dehydration means 4 is configured to compress the residue using the supply means, increase the pressure to a value necessary for dehydration, and maintain the pressurized state for a predetermined period of time even when the supply means is retracted. Examples thereof are shown in FIGS. 3 to 6. This pressurized dehydration means 4 is a main body 31a on the horizontal supply side of the dehydration device 3.
and the main body 31b on the bent discharge side,
The embodiment shown in FIG. 3 has flanges 41 and 42 connected to the body 31 at both ends facing each other,
A large number of tapered plates 43 are arranged and installed at a predetermined pitch in a broken ring shape between 1.42 mm, and the inner surface of the flange and the tip end surface of the tapered plates are butted against each other and integrated by welding or the like. This tapered plate 43 is connected to the flange 41
．． 42, the inner circumferential side at both ends becomes a tapered surface 43t.

This is done by cutting a flat bar with the required thickness and width into a fixed size, and forming both ends of the inner circumferential surface of the bar at a required inclination angle θ such that the tip side is lower. )
As shown in the figure, a large number of them are arranged in a ζ-cut annular shape, and a slit-like gap 4H is formed between adjacent Taber plates 43, 43, and this gap is used as a dehydration hole. Further, the length L of the flat portion of the inner circumferential surface of the tapered plate 43 has a length that can accommodate approximately the sludge supplied by one stroke of the piston 32b. In this way, the pressurized dehydration means 4
The sludge is sandwiched between the opposing main bodies 31 and 31, and the flanges are fixed with bolts or the like, and the residue is supplied into the hopper 2 by the supply means 3 every one stroke of the piston of this supply means. Then, it is pushed out into the discharge side main body 31 by the piston 32b which moves forward from within the horizontal supply side main body. At this time, the residue pushed out by the advancing piston is pushed out into the pressurized dewatering means 4 by one stroke - 0 minutes. At this time, the required squeezing is performed to remove water, and the water is drained from between the Taber plates. Even if the piston 32b moves back, the residue is pushed into the pressurized dehydration means 4.The time required until the piston moves forward and the next stroke of the residue is pushed out into the pressurized dehydration means. The press is stopped and the pressurized state is maintained for dehydration.

Note that as the piston 32b retreats, the next residue is supplied from the hopper to the position in front of the piston.

In this way, the residue corresponding to one stroke of the piston is supplied to the pressurized dewatering means, and the residue is intermittently dehydrated. The pressurized dewatering means 4 smoothly pushes out the waste into the discharge side main body 31b. This is because the cross-sectional area of the discharge side main body 31b is larger than the cross-sectional area of the pressurized dewatering means 4, and the residue after pressurized dehydration has more frictional resistance with the main body 31 than when pressurized. Reduce value (flow resistance) and lighten residue transport. Further, a cylindrical conveyance means 5 is connected to the tip of the discharge side main body 31b, and this conveyance means 5
It is arranged in a vertical direction or at a required angle of inclination so as to have approximately the same cross-sectional area as b and to have a required lift H from the pressurized dewatering means 4, and the upper end of the conveying means 5 is used as a discharge port to dewater and store residue. The liquid is discharged into the hopper 6.

Note that this dewatered residue storage hopper 6 is provided with an opening/closing gate at the lower end, so that a truck or the like can enter the lower part of this hopper 6 and transfer the dewatered residue from the hopper to the truck.
is placed at a predetermined height on a pedestal 7.

In addition, pressurized dehydration means 4 and supplying residue I4+, picture means 3
In the embodiment shown in Fig. 1, a hydraulic cylinder is used, but in this case, the residue is supplied to the pressurized dewatering means intermittently for each stroke of the piston, or in the embodiment shown in Fig. 2, a screw conveyor is used. The soybean residue can be supplied continuously, and in this case, the soybean residue is maintained in a pressurized and compressed state for the time it travels along the length of the flat portion of the tapered plate 43, and is continuously dehydrated.

The pressurized dehydration means 4 shown in FIG. 4 has the shape of a vibrator 45, and has a large number of dehydration holes 4H bored in its outer periphery, and has a small diameter at the center and a tapered shape at both ends to have a large diameter. is narrowed down to a small diameter, and a main body 31 is provided on both end faces of the body.
This tapered surface 43 is provided with a flange for mounting on the
The angle θ of t, the length L of the flat portion, etc. are the same as in the embodiment shown in FIG.

The embodiment shown in FIG. 5 is a modification of the one shown in FIG. 4, with flanges protruding from both ends, the pipe-shaped main body portion 46 having a large diameter on the supply side and a tapered shape with a small diameter on the discharge side, and A large number of dehydration holes 4H are bored in the surface, and when the residue is pressurized and supplied to this pressurized dehydration means and moves to the discharge side, it is dehydrated and when it comes out from the discharge port to the main body side, the residue is This is to reduce the pressure and squeezing state of the material due to the difference in cross-sectional area, thereby reducing the flow resistance.

In the embodiment shown in FIG. 6, a Taper pipe 47 protruding from the inner peripheral surface of the supply side flange is aligned with the tip side Taper surface of the tapered plate 43 shown in FIG. This is similar to the embodiment shown in FIGS.

In the slag dehydrator constructed as described above, the movement resistance (pushing force) R of the scum is related to the pressure of the scum and is expressed by the following equation.

Resistance in the axial direction when the R rainbow residue moves P: Internal pressure μ: Friction coefficient between the residue and the main body wall π: Circumference ratio 2 The pressure distribution inside the diameter pipe of the main body is as shown in Figure 10 (1) Accordingly, from the above equation, the resistance (pushing force) R in the conventional method of applying back pressure along the entire length of the pipe has a value corresponding to the area surrounded by &+&ZC in the figure below, but in the resistance method, the value is equivalent to a, a' ,b”,b
The value corresponds to the area surrounded by ', c, and the resistance is less by the amount indicated by the hatching, so it can be pushed with a small force.

Furthermore, the relationship between the ratio d/D of the inner diameter d of the small diameter part and the inner diameter of the large diameter part of the pressurized dehydration means and the resistivity is shown in FIG. 7, and the relationship between the Taber angle θ and the resistance is shown in FIG. The relationship between the length of the flat portion and the resistance is shown in FIG. 9, and the relationship between the internal pressure of the residue and the water content of the dehydrated residue is shown in FIG. 10.

Therefore, if the time when the piston is pressurized (pressure holding time) is long, water can be removed well even at low pressure, and for this reason, the scum remains in the high pressure area until the next time the piston pushes out the residue, so the piston can be moved back immediately. Processing capacity can be improved. Furthermore, separation from water in the pressurized dehydration section is good, and efficient dehydration can be performed.

〔Effect of the invention〕

According to the present invention, the supply means is provided with a pressurized dewatering means whose inner diameter is locally curved at the forward end position of the supply means, and the sludge supply pressure during squeezing is increased to a value necessary for dehydration, and the scum is passed through the pressurized dewatering means. Since the subsequent flow resistance within the main body is reduced, the pressurized dehydration of the residue can be carried out efficiently, and it has the advantage of reducing the flow resistance.

[Brief explanation of the drawing]

Fig. 1 shows a first embodiment of the present invention, Fig. 2 shows a second embodiment, and Figs.
The figures are explanatory diagrams of different embodiments of the pressurized dehydration means, Figs. 7, 8, and 9 are graphs showing changes in sludge flow resistance, and Fig. 10 is a graph showing the length of the pressure dehydration means and the sludge pressure. It is a graph diagram showing the relationship between. 2 is a hopper, 3 is a supply means, 4 is a pressurized dehydration means, and 5 is a conveyance means. Figure 4 (B) Figure 7 Figure 9 Figure 8

Claims (3)

[Claims] (1) In a duct for dewatering and transporting residue having a required diameter and a required lift, the upper end serves as a dehydration and residue discharge port, and the lower end is equipped with a means for supplying residue under pressure. Equipped with pressurized dehydration means that locally narrows the inner diameter, increases the supply pressure of the residue during squeezing to the value necessary for dehydration, and reduces the flow resistance within the main body after passing through the pressurized dehydration means. A residue dehydrator featuring: (2) The sludge dehydrator according to claim 1, wherein the resistance during sludge dehydration is changed by changing the ratio between the inner diameter of the pressure dehydrating means formed in the cylindrical body and the inner diameter of the cylindrical main body. (3) The residue dehydrator according to claim 1, wherein the length of the pressurized dehydration means formed in the cylindrical main body is changed to change the residue dehydration time.