JPS6171811A - Backwashing apparatus for waste water treatment apparatus - Google Patents

Abstract

PURPOSE:To simplify a mechanism and to automatically perform the backwashing of a filter membrane, by performing the backwashing of the filter membrane almost periodically by utilizing filtered water. CONSTITUTION:When water to be treated is filtered by a filter apparatus, filtered water passes through a drain pipe 33 and a cylinder part 45 to be stored in a fixed water tank 41. When the amount of the filtered water increases in the fixed water tank 41, a float ball 63 rises and a shaking valve body 61 is drawn up to open an outflow port 59 and the filtered water in the fixed water tank 41 is flowed into a movable water tank 67 from the outflow port 59. When the amount of the filtered water in the movable water tank 67 increases, the movable water tank 67 falls against a compression spring 71 and, with the falling of said tank 71, the piston lever 75 and piston 47 of a change-over valve mechanism 43 are fallen to allow the piston 47 to reach the state shown by an imaginary line and compressed air pushed the filtered water and, as a result, the filtered water is flowed backwardly. Whereupon, the filtered water passes through a filter membrane from a secondary side to a primary side along with air to wash off the residue on the surface of the filter membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a backwashing device used in a wastewater treatment device.

[Prior art]

In wastewater treatment equipment equipped with a filter membrane, if residue adheres to the filter membrane, the filtration ability will be degraded.

For this reason, it is necessary to periodically reverse flow of fluid pressure from the secondary side of the filter membrane to remove the residue adhering to the filter membrane, so-called backwashing.

Conventionally, backwashing of the filter membrane has been carried out by pumping fresh water or air, but the backwashing control operation is performed manually after stopping the reactor water treatment equipment at the appropriate time. It was also performed periodically by electrical means using a timer valve or the like.

Therefore, in the former case, management and work are difficult due to manual operation, and in the latter case, the mechanism of the device becomes complicated and the cost inevitably increases.

[Purpose of the invention]

The present invention was made based on this situation, and its purpose is to provide a backwashing device for wastewater treatment equipment that has a simple mechanism and does not require manual operation.

[Structure of the invention]

This purpose is to provide a backwashing device for a wastewater treatment device in which filtered water is caused to flow back from the secondary side of the filter membrane in the filtration device almost regularly by fluid pressure to wash the filter membrane, and the A switching valve mechanism that switches between forward flow and reverse flow of filtered water, a fixed water tank in which the filtered water that has passed through this valve mechanism is temporarily stored, and a fixed water tank into which the filtered water flows when it reaches a predetermined amount. This was achieved by installing a movable water tank that operates according to changes in the amount of water and weight, and by following the operation of the movable water tank to appropriately switch between forward flow and reverse flow of filtrate water.

[Explanation of Examples]

The present invention will be described in detail below based on the drawings.

1 and 2 illustrate a first embodiment of the invention.

In FIG. 1, 11 is a water tank, and 13 is a partition wall, which is installed inside the water tank 11 and divides the inside of the water tank 11 into an aeration tank 15 and a settling tank 17. Here, the aeration tank 15 is the water to be treated W.
This is a tank for purifying water using purifying microorganisms, and a settling tank 1
7 is a tank in which floating matter in the purified water W to be treated is precipitated.

A gap 19 is formed between the lower edge of the partition wall 13 and the bottom surface of the water tank 11. This gap 19 is the aeration tank 15
and the sedimentation tank 17 are communicated with each other.

In the aeration tank 15, 21 is an inflow pipe;
It is installed at the top of the. This inflow pipe 21 supplies the water W to be treated to the aeration tank 15.

Further, 23 is an oxygen supply pipe, which is installed at the lower part of the aeration tank 15 from the partition wall 13 toward the opposite side of the partition wall 13. This oxygen supply pipe 23 supplies oxygen to the purifying microorganisms in the aeration tank 15 and generates convection in the water W to be treated (in the direction of the arrow).

25 is a filtration device, which is installed above the settling tank 17. This filtration device 25 includes a required number of through holes 27, 27,
A filter membrane 31 is ultrasonically welded to a tubular body 29 in which... are bored. The filtered water W to be treated by the device 25 is sent to the backwash device R through the discharge pipe 33.

Next, the backwashing device R will be explained in detail based on FIG.

In the figure, 41 is a fixed water tank, which is screwed to the outer wall of the water tank 11. Filtered water from the discharge pipe 33 flows into the fixed water tank 41 via the valve mechanism 43.

The valve mechanism 43 includes a cylinder portion 45 and a piston 47 that moves forward and backward within the cylinder portion 45. The cylinder part 45 has a filtered water inflow hole 49 at the lower end for communication with the discharge pipe 33, a filtered water outflow hole 51 at the bottom for communication with the fixed water tank 41, and a pressurized air inflow pipe 53 opening at the side wall for air. It has an inflow hole 55 and an air discharge hole 57 at the upper end for communicating with the discharge pipe 33. For this reason, the cylinder portion 4
5, when the piston 47 is raised (the state indicated by the solid line in the figure), the discharge pipe 33 and the fixed water tank 41 are in communication via the cylinder portion 45, and the air inflow hole 55 is closed by the piston 47. Therefore, the filtered water that has passed through the discharge pipe 33 flows into the fixed water tank 41. Note that at this time, since the air inflow hole 55 is closed by the piston 47, it does not flow toward the discharge pipe 33, so that the filtered water does not flow back.

On the other hand, when the piston 47 is lowered (shape 3 of the virtual line in the figure), the air inflow pipe 53 and the discharge pipe 33 communicate with each other via the cylinder portion 45 and the air discharge hole 57, and the filtered water inflow hole 49 Because it is closed, pressurized air flows through the exhaust pipe 3.
As a result of flowing in three directions and causing the filtered water to flow backwards, the filtered water passes through the filter membrane 31 of the filtration device 25 from the secondary side to the primary side and washes away the residue on the surface of the filter membrane 31.

The piston 47 is moved up and down by the operation of a piston rod 75, which will be described later.

Further, an outflow hole 59 is bored in the bottom of the fixed water tank 41. This outflow hole 59 allows filtered water to flow into a movable water tank 67 (in the direction of the arrow), which will be described later. 61 is a swinging valve body, which is pivotally supported on the bottom surface of the fixed water tank 41. This swinging valve body 61 is for opening and closing the outflow hole 59. Further, 63 is a floating ball, which is floated on the surface of the filtered water in the fixed water tank 41.

Since the floating ball 63 and the swinging valve body 61 are connected by a chain 65, the swinging valve body 61 can be opened and closed depending on the height of the water surface of the filtered water. That is, when the amount of filtered water is small, the swing valve body 61 is closed, but when the amount is large, it opens.

Next, 67 is a movable water tank, which is placed via a compression spring 71 on a base 69 that is integrated with the water tank 1 structure.

The movable water tank 67 receives the filtered water from the fixed water tank 41 from the upper lower part 3, and moves up and down as its weight changes. 75 is a piston rod, and the upper plate 67a of the movable water tank 67
is fixed. This piston rod 75 is connected to the valve mechanism 4.
It is connected to the piston 47 of No. 3. Therefore, when the movable water tank 67 moves up and down, the piston 47 also moves up and down, operating the valve mechanism 43.

Further, 77 is a discharge hole, which is bored in the bottom surface of the movable water tank 67. This discharge hole 77 is for discharging the filtered water to the outside of the device R. 79 is a valve body, and this discharge hole 7
7 in a resilient state by a compression spring 81. This valve body 79 is composed of an integrally formed disc 83a and an operating rod 83b, and when the movable water tank 67 is lowered and the operating rod 83b abuts against the reference surface 85, the reference surface
It opens against the compression spring 81 due to the reaction force received from the compression spring 81.

C Operation of the first embodiment] First, when there is no filtered water in the movable water tanks 6 and 7, the piston 47 is raised in the valve mechanism 43 (the state indicated by the solid line in the figure), so the air supply pipe 53 and the discharge pipe 33 is blocked, and the discharge pipe 33 and the fixed water tank 41 are in communication. When the water to be treated is filtered by the filtration device 25 in this state, the filtered water flows through the discharge pipe 33 and eventually into the cylinder section 45.
The water passes through and is stored in a fixed water tank 41. When the amount of filtered water increases in the fixed water tank 41, the water surface rises, so the floating ball 63 rises, and as a result, the swinging valve body 61 is pulled up and the outflow hole 59 is opened. Then, fixed water tank 4
The filtered water in 1 flows into the movable water tank 67 from the outflow hole 59.

When filtered water is poured into the movable water tank 67 and the amount of water increases, the movable water tank 67 moves down against the compression spring 71.

Then, the piston rod 75 of the valve mechanism 43 and, in turn, the piston 47 move downward, so that the piston 47 is in the virtual line state, and the air supply pipe 53 and the discharge pipe 33 are communicated with each other, and the fixed water tank 41 and the discharge pipe 33 are connected. The pressurized air presses on the filtrate, causing the filtrate to flow backwards. Then, the filtered water together with the air passes through the filter membrane 31 from the secondary side to the primary side, washing away the residue on the surface of the filter membrane 31.

Note that when the movable water tank 67 is lowered to its lowest position, the operating rod 11?3b of the valve body 79 comes into contact with the reference surface 85 and receives a reaction force from the reference surface 85, so that it is opened against the compression spring 81. As a result, the filtered water in the movable water tank 67 flows to the outside through the discharge hole 77. When the amount of filtered water in the movable water tank 67 decreases, the movable water tank 67 rises, so the valve body 79
closes the discharge hole 77 by the compression spring 81, and the piston rod 75 and eventually the piston 47 are pushed up (
The shape of the solid line in the diagram! 3). Then, the supply of compressed air to the discharge pipe 33 is stopped, and the discharge pipe 33 and the fixed water tank 41 are communicated with each other, so that the filtered water becomes a forward flow and filtration starts again.

In this way, such a device R automatically repeats filtration and backwashing.

Note that fresh water can be used instead of air as a means of backwashing.

[Description of second embodiment]

FIG. 3 shows a second embodiment of the present invention, in which a movable water tank 67 swings.

〔Effect of the invention〕

The wastewater treatment device according to the present invention is a backwashing device for a wastewater treatment device that washes the filter membrane by substantially regularly backflowing filtered water from the secondary side of the filter membrane in the filtration device using fluid pressure. A switching valve mechanism that switches between forward flow and reverse flow of filtrate in the discharge pipe, a fixed water tank in which the filtrate that has passed through this valve mechanism is temporarily stored, and a fixed water tank into which the filtrate flows when it reaches a predetermined amount. At the same time, a movable water tank that operates according to changes in the weight of the amount of water flowing in is installed, and the valve mechanism follows the operation of this movable water tank to appropriately switch between forward flow and reverse flow of the filtered water.

That is, since the filter membrane is backwashed approximately regularly using filtered water, the mechanism is simple and the filter membrane can be backwashed automatically.

[Brief explanation of drawings]

1 and 2 show an embodiment of the wastewater treatment device according to the present invention, FIG. 1 is a sectional view, and FIG.
3 is an enlarged cross-sectional view of part ■ in the figure.
FIG. 25 ... Filtration device 31 ... Filter membrane 33 ... Discharge pipe 41 ... Fixed water tank 43 ... Switching valve mechanism (valve mechanism) 67
... Movable Water Tank Patent Applicant: Asahi Malleable Iron Co., Ltd. Agent: Patent Attorney: Yuji Nozue - First Design and O

Claims (3)

[Claims] (1) In a backwashing device for a wastewater treatment device that washes the filter membrane by backflowing the filtered water almost regularly by fluid pressure from the secondary side of the filter membrane in the filtration device, the filtered water in the discharge pipe of the filtering device is a switching valve mechanism that switches between forward flow and reverse flow; a fixed water tank in which the filtered water that has passed through this valve mechanism is temporarily stored; A backwashing device for a wastewater treatment device, in which a movable water tank that operates according to a change in weight is installed, and the valve mechanism follows the operation of the movable water tank to appropriately switch between forward flow and reverse flow of filtrate. (2) The backwashing device for a wastewater treatment device according to claim 1, wherein the movable water tank moves up and down. (3) The backwashing device for a wastewater treatment device according to claim 1, wherein the movement of the movable water tank is rocking.