JP2002194808A - Scum removing device for sewage tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in conventional scum removing devices for sewage tank that a one for circulating the sewage in a sewage tank cannot often remove the firmly stuck scum, and a one for removing the scum by the discharge of sewage by a shower or a tapered nozzle often clogging shower opening or nozzle opening with filth. SOLUTION: This scum removing device for sewage tank comprises a discharge conduit 30 for discharging part of the sewage sucked by a pump 11 into the sewage tank through an opening part 41 and a water receiving part 50. The pump 11 starts to operate when the level of the sewage in the sewage tank reaches a prescribed pump starting level W1. The discharge conduit 30 discharges the sewage from the opening part 41 so as to collide with the water receiving part 40. The water receiving part 40 reflects and disperses the sewage discharged from the opening part 41. In response to the collision of the sewage to the water receiving part 50, the valve element 43 of a valve 40 moves from an opening position for opening the discharge conduit 30 to a closing position for closing the discharge conduit 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scum removal device for removing scum generated in a sewage tank, and more particularly, to a scum removal device using pressure water supplied from a pump for pumping up sewage and discharging the scum out of the sewage tank. And a scum removing device for removing scum.

[0002]

2. Description of the Related Art When sewage flows into a sewage tank such as a manhole, scum adheres to the inner wall surface of the sewage tank, a submersible pump, a water level gauge, pipes, cables, etc. due to the organic substances and fats and oils components of the inflowed sewage. . If the scum adheres to, for example, a float type water level meter, it causes the water level meter to malfunction. If left untouched, scum will generate harmful and off-flavor hydrogen sulfide. Hydrogen sulfide is corrosive and causes corrosion of the sewage tank. When the scum starts to adhere to the inner wall surface or the like of the sewage tank, the scum further adheres to the scum so as to be stacked thereon. When scum accumulates and adheres to the inner wall surface or the like of the sewage tank as described above, it becomes difficult to clean and remove it.

Conventionally, many manholes have been regularly cleaned by a high-pressure cleaner in order to wash out such scum. In addition, scum may be removed by circulating sewage in a sewage tank. In addition, in the circulation of sewage, a scum adhesion preventing device using a flash valve utilizing an ejector effect (for example, see Japanese Patent Application Laid-Open No. 7-76873),
There has been proposed an apparatus that circulates sewage in a sewage tank using an electric valve or a mixer to prevent scum from adhering.

[0004]

However, the conventional scum removing method has the following problems.

If regular cleaning is performed by a high-pressure cleaning machine, a high-pressure cleaning machine is naturally required. In addition, regular cleaning requires human labor. Thus, the cost and labor for cleaning are large.

[0006] In addition, circulating sewage in a sewage tank alone may not remove scum firmly attached.
Scum is particularly likely to adhere near the pump starting water level,
In order to sufficiently remove the scum attached and deposited here, it is necessary to generate a strong circulation. For that purpose, the power source for circulation must be large.

[0007] Further, if the wastewater in the wastewater tank is circulated more than necessary, the driving force of the pump, which should be used for discharging the wastewater to the outside of the manhole, is wasted.

Further, in an apparatus for removing scum by discharging sewage from a shower or a tapered nozzle, the shower opening and the nozzle opening are easily clogged with dirt and the like, and after all, the shower and the nozzle are periodically cleaned manually. I have to.

According to the present invention, it is possible to sufficiently remove scum that easily accumulates in the sewage tank, particularly in the vicinity of the pump starting water level, and also to reduce running costs by reducing maintenance and to reduce manufacturing costs. It is an object to provide such a scum removing device.

[0010]

In order to solve the above-mentioned problems, a scum removal apparatus for a sewage tank according to the present invention comprises a pump for pumping sewage from a sewage tank and discharging the sewage to the outside of the sewage tank. A discharge pipe for discharging a part of the sewage pumped by the pump from the opening into the sewage tank, and a water receiving portion, wherein the pump is provided with a sewage in the sewage tank. When the water level reaches a predetermined pump start water level, the start is started, the opening is provided at a position higher than the start water level in the sewage tank, and the water receiving section is activated in the sewage tank. The discharge pipe is provided at a position higher than the water level, and the discharge pipe discharges the sewage from the opening so as to collide with the water receiver, and the water receiver reflects the sewage discharged from the opening. In response to the sewage collision with the water receiving portion, the valve body of the valve The transition from open position to open a conduit to a closed position for closing the said discharge exit conduit (claim 1). According to this configuration, when the pump is started, the sewage discharged from the opening of the discharge pipe collides with the water receiving portion, is diffused and falls, and removes the scum near the pump starting water level. On the other hand, in response to the sewage colliding with the water receiving portion, the valve body of the valve of the discharge pipe shifts from an open position for opening the discharge pipe to a closed position for closing the discharge pipe. Therefore, shortly after the discharge of the sewage from the opening is started, the discharge pipe line is closed, and the discharge of the sewage from the opening is stopped.

[0011] In the above scum removal apparatus for a sewage tank,
If the water receiving portion diffuses the sewage discharged from the opening in a substantially horizontal direction (claim 2), the diffusion range of the sewage can be increased.

In the scum removal device for a sewage tank, the water receiving portion may diffuse the sewage discharged from the opening in substantially the entire circumferential direction with respect to a vertical axis. 3) The diffusion range of sewage can be further increased.

In the scum removing device for a sewage tank, the opening is provided upward, the water receiving portion has a downward surface, and the sewage discharged from the opening is reflected by the downward surface. (Claim 4).

Further, in the scum removing device for a sewage tank, the downward surface of the water receiving portion may be a concave curved surface.

In the scum removing device for a sewage tank described above, the valve body of the valve shifts from the open position to the closed position in response to sewage collision with the water receiver. The water receiving portion and the valve may be connected by any means so that the force is transmitted to the valve body from the valve body. For example, the water receiving portion and the valve are connected by a liquid path, and the water receiving portion is The hydraulic fluid in the fluid path is pressure-fed from the water receiving part side to the valve side by receiving the collision of the sewage, and the hydraulic pressure of the hydraulic fluid fed to the valve side causes the hydraulic fluid to flow from the flow path in the valve. The valve body retracted to the deviated position may be pushed toward the flow path (claim 6).

In the scum removing device for a sewage tank, the valve body may be a ball.

In the scum removing device for a sewage tank described above, if the opening is an opening on the outlet side of the valve (claim 8), the configuration of the device is simplified.

In the scum removing device for a sewage tank described above, if the distance from the opening to the water receiving portion is longer than the diameter of the opening (claim 9), it passes through the opening. The waste that is generated is not trapped between the opening and the water receiving portion. That is, clogging due to filth is prevented.

In the scum removing device for a sewage tank, the discharge pipe may be branched from a pressure feed pipe interposed between the pump and a discharge pipe of the sewage tank. 10).

[0020]

Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 4). FIG. 1 is a longitudinal sectional view of a manhole 10 as a sewage layer. In this manhole 10, a scum removing device as one embodiment of the present invention is applied. The manhole 10 is mainly composed of a bottom plate 2 placed on a crushed stone foundation 3, a tubular manhole body 1 mounted on the bottom plate 2, and a manhole cover 4 for closing an upper end opening of the manhole body 1. It is composed of Manhole 10 is buried underground.

A sewage inflow pipe (not shown) is connected to the manhole 10, and sewage as sewage is supplied into the manhole 10 from the sewage inflow pipe.

The manhole 10 is provided with a main piping system for pumping and discharging sewage. The main piping system is mainly
It comprises a submersible pump 11, a pressure feed line 25, and a discharge tube 15. Although the two submersible pumps 11 and the pressure feed pipes 25 are symmetrically arranged, members having the same reference numerals have the same structure.
Pumping line that guides sewage discharged by submersible pump 11 to discharge pipe 15
Reference numeral 25 mainly includes a pressure feed pipe 12, a check valve 13, and a ball valve 14. The discharge pipe 15 is a bifurcated pipe 15a and a straight pipe 15b
And are connected. Two ball valves 14 are connected to the bifurcated pipe 15a.

The submersible pump 11 is installed near the bottom of the manhole 10. The submersible pump 11 has a suction port 11a at the bottom.
And feeds the sewage sucked from the suction port 11a to the pressure feed pipe 25. The pumped sewage flows through the discharge pipe 15 and is discharged to the outside of the manhole 10.

A chain 21 hangs from the vicinity of the manhole cover 4 inside the manhole 10. A bubble type water level gauge 22 is attached to the tip of the chain 21.

W1 indicates a pump activation water level at which the submersible pump 11 starts activation. Scum is particularly likely to accumulate near the pump starting water level. Manhole 10 as in Figure 1
Then, the scum is particularly likely to adhere to the vicinity of the pump starting water level on the inner wall surface 1a of the manhole main body 1 or the vicinity of the pump starting water level on the side surface of the pressure feed pipe 25.

W2 is a pump stop timer operation water level at which a timer for measuring a time until the submersible pump 11 is stopped starts operating.

W3 is a pump automatic stop water level indicating the water level of sewage when the submersible pump 11 stops.

A sprinkling unit U constituted by a discharge pipe line, a water receiving section and the like is connected to a joint between the pressure feeding pipe 12 and the check valve 13.

FIG. 2 is a diagram showing the sprinkling unit U and members in the vicinity thereof. FIG. 2A shows the sprinkling unit U and the check valve 13.
And FIG. 2 (b) is a partial sectional side view of the ball valve 14.
FIG. 3 is a partial cross-sectional view taken along the arrow B in FIG. The state in FIG.
This is a state in which the submersible pump 11 has not been started, and therefore no sewage is being guided to the sprinkling unit U.

The sprinkling unit U mainly includes a discharge pipe 30, a sprinkling plate 50 serving as a water receiving portion, a cylinder 51, a piston 52, and an oil chamber 5.
5. It comprises a tube 56, a needle valve 58, an oil chamber 48, and a support column 57.

The discharge pipe 30 is connected at the inlet of the check valve 13 so as to branch off from the pressure feed pipe 25. The discharge pipe 30 is mainly composed of a branch pipe 32, a ball valve 34, a connection pipe 36, and a valve 40.

The branch pipe 32 branches the flow path of the sewage from the pressure feed pipe 25. A ball valve 34 is connected to the tip of the branch pipe 32. Further, the ball valve 34 is connected via a connecting pipe 36 to the valve.
Connected to 40. No pipe is connected to the opening 41 on the outlet side of the valve 40. The opening 41 faces upward. The opening 41 is at a position higher than the pump starting water level W1. Note that the valve 40 corresponds to a “valve” in the claims, and the opening 41 corresponds to an “opening” in the claims.

The cylinder 51 is attached to the valve 40 by a column 57. The cylinder 51 is disposed above the valve 40 such that the axial direction thereof coincides with the vertical direction. The piston 52 is slidable with respect to the cylinder 51,
It is inserted through 51. The sprinkling plate 50 is attached to the lower end of the piston 51. The sprinkling plate 50 is located right above the opening 41 of the valve 40. The sprinkling plate 50 functions as a water receiving unit that receives sewage discharged from the opening 41 of the valve 40. The sprinkling plate 50 has a shape as if a part of the spherical surface was cut out. The upper surface 50a of the sprinkling plate 50 has a convex curved shape, and the back surface, that is, the lower surface 50b, has a concave curved surface shape. Lower surface 50b which is a downward facing surface
Faces the opening 41. The distance between the opening 41 and the lower surface 50b is set to be longer than the diameter of the opening 41.

The oil chamber 55 is formed by a lid 53 connected to the cylinder 51 by bolts, and a flexible diaphragm 54 provided inside the lid 53. This diaphragm
54 is made of a flexible material such as rubber. The volume of the oil chamber 55 varies depending on the state of the diaphragm 54. In the state shown in FIG. 2, the oil chamber 55 is filled with oil,
This is the state when the volume of the maximum has been reached.

The oil chamber 48 is formed by a side wall 46 closing a side portion of the valve 40, and a flexible diaphragm 47 provided inside the side wall 46. The diaphragm 47 is made of a flexible material such as rubber. The volume of the oil chamber 48 is
It varies depending on the state of the diaphragm 47. FIG. 2 shows a state where the diaphragm 47 is stuck to the inner surface of the side wall 46 and the oil chamber
This is the state when the volume of 48 becomes minimum.

An opening 53a provided in the lid 53 and an opening 46a provided in the side wall 46 are connected via a tube 56 and a needle valve 58. As a result, the oil chamber 55 and the oil chamber 48
Is communicated.

As described above, the oil chamber 55, the tube 56, the needle valve 58 and the oil chamber 48 form an oil path as a liquid path. This oil path is filled with oil as a working fluid. This oil passage is used by the valve 40 to transmit the force that the sprinkling plate 50 receives from the sewage.
It acts to transmit to the ball 43 inside.

The valve 40 is mainly composed of a ball 43 serving as a valve body and a valve chamber 42 for accommodating the ball 43. Valve room
42 is formed by a housing 44 and a diaphragm 47. A guide 45 is formed on the inner surface of the housing 44, and the movement direction of the ball 43 is regulated by the guide 45. The connection pipe 36 is connected to the opening at the lower end of the housing 44, and no member is connected to the opening 41 at the upper end. The ball 43 can move along a guide 45 from a position near the side wall 46 shown in FIG.

When the ball 43 is located near the side wall 46,
The discharge line 30 is open. That is, this state is a state where the ball 43 is located at the opening position.

When the ball 43 comes to a position that closes the opening 41, the discharge pipe 30 is closed. That is, this state is a state where the ball 43 is located at the closed position.

FIG. 3 is a cross-sectional view of the valve 40, the sprinkler plate 50 and the peripheral members thereof. According to FIGS. 3 (a) to 3 (d), the ball 43 of the valve 40 is moved from the open position to the closed position. The state up to the transition is shown step by step. Hereinafter, FIGS. 1 and 3
The operation state of the wastewater tank scum removal device according to the present embodiment will be described with reference to FIG.

First, when sewage flows into the manhole 10 from a sewage inflow pipe (not shown) connected to the manhole 10, and when the level of the sewage reaches the pump starting water level W1, the bubble type water level meter is used.
The control device (not shown) to which the output signal from 22 is input detects this and issues a start command to the submersible pump 11. The submersible pump 11 starts to start, and pumps the sewage sucked from the suction port 11a to the pressure feed pipe 25. Then, the sewage pumped is discharged to the outside via the discharge pipe 15.

On the other hand, the sewage flowing through the pressure feed line 25 also branches and flows out to the sprinkling unit U. The branched sewage is valved via the branch pipe 32, the ball valve 34, and the connection pipe 36 of the watering unit U.
Reach 40. The sewage that has reached the valve 40 passes through the valve chamber 42 while maintaining its momentum. At this time, the ball 43
As shown in (a), since it is retracted to a position outside the flow path in the valve chamber 42, it does not move from there. Here, the flow path refers to a range connecting the opening at the lower end of the housing 44 to the opening 41 at the upper end.

Next, the sewage that has passed through the valve 40 is discharged from the opening 41, and as shown in FIG.
Collide with Then, the sprinkling plate 50 reflects and diffuses the sewage. In FIG. 3B, the arrow indicates the flow direction of the wastewater. The diffusion direction of the sewage is substantially horizontal as shown in FIG. Further, since the sprinkling plate 50 has a form that is rotationally symmetric with respect to the central axis of the piston 52, the sewage is diffused in substantially the entire circumferential direction with respect to the central axis of the piston 52, that is, the vertical axis. Since no member is attached to the opening 41 and the opening 41 is in an open state, sewage is discharged from the opening 41 vigorously. At this time, since the ball 43 has retreated to a position outside the flow path in the valve chamber 42, the ball 43 is not easily affected by the flow. Therefore, the ball 43 may be light. Further, since the sewage discharged from the opening 41 directly collides with the sprinkling plate 50, the momentum of the sewage reflected by the sprinkling plate 50 can be increased. In this way, since the momentum of the sewage diffused by the sprinkling plate 50 can be increased, the opening
It is not necessary to narrow the opening area of 41 as small as a nozzle.
Therefore, clogging of the opening 41 with waste is unlikely.

FIG. 4 is a sectional view taken along line AA of FIG. The arrows in FIG. 4 indicate the diffusion direction of the wastewater reflected by the sprinkling plate 50. As shown in this figure, the sewage is diffused in substantially the entire circumferential direction with respect to the vertical axis.

The sewage reflected from the sprinkling plate 50 falls and falls on the inner wall surface 1a of the manhole main body 1 so that the pump activation water level W1
It collides with the scum attached to the vicinity and removes the scum. In addition, the sewage reflected from the sprinkling plate 50 collides with scum attached to the vicinity of the pump starting water level W1 on the side of the pumping line 25, and removes the scum.

Referring again to FIG. 3B, the opening 41
The sprinkling plate 50 receives a force in the direction of being pushed upward by receiving the sewage discharged from the water. Then, the piston 52 attached to the sprinkling plate 50 moves upward in the cylinder 51. Then, the upper end surface of the piston 52 pushes up the diaphragm 54. When the diaphragm 54 is pushed up, the oil chamber
The volume of 55 becomes small, and the oil, which is the hydraulic fluid, pushed out of the oil chamber 55 flows into the oil chamber 48 via the tube 56 and the needle valve 58. Then, the diaphragm 47 starts to deform so as to increase the volume of the oil chamber 48. Gradually, the diaphragm 47 pushes the ball 43 toward the flow path of the valve 40. When the ball 43 is pushed toward the flow path of the valve 40 to some extent, the ball 43 hits the flow of sewage in the valve chamber 42 and moves along the guide 45 in a direction further closer to the flow path in the valve 40.

Then, the ball 43 reaches a closed position for closing the opening 41 as shown in FIG. Then, the discharge pipe 30 is closed, and the discharge of the sewage from the opening 41 also stops.

Then, the sewage does not collide with the sprinkling plate 50 and the force for pushing up the piston 52 does not work. On the other hand, the driving pressure of the submersible pump 11 acts in the valve chamber 42 through the opening at the lower end of the housing 44.
The diaphragm 47 is pushed back toward the side wall 46 by the positive pressure in the valve chamber 42. Then, the oil flows through the oil passage in a direction from the oil chamber 48 to the oil chamber 55, and the diaphragm 54 is deformed so that the oil chamber 55 becomes large. Eventually, the diaphragm 54 returns to the original state, that is, the state where the volume of the oil chamber 55 is maximized,
The oil chamber 48 returns to a state where its volume becomes minimum (FIG. 3D).
reference). Further, the piston 52 returns to the lowest position with respect to the cylinder 51. During the operation of the submersible pump 11, since the water pressure of the sewage acts in the valve chamber 42, the ball 43
Is maintained in a closed position for closing the opening 41 as shown in FIG.

When the submersible pump 11 continues to pump sewage in the manhole 10 to the outside, the water level of the sewage in the manhole reaches the pump stop timer operation water level W2. Then, the control device knows this from the output signal from the bubble type water level gauge 22, and activates a timer for measuring the time until the submersible pump 11 is stopped. Then, when a predetermined time has elapsed from the timer operation, the control device issues a stop command to the submersible pump 11. At this time, the water level of the sewage substantially matches the pump automatic stop water level W3. When the submersible pump 11 stops, the driving pressure of the submersible pump 11 does not act on the valve chamber 42, and the ball 43 returns to the open position shown in FIG.

The state from the start to the stop of the operation of the scum removing device for a sewage tank has been described mainly with reference to FIGS. 1 and 3 (a) to 3 (d). As understood from the above description,
Every time the submersible pump 11 is started, scum is washed and removed in the sewage tank, so the inner wall 1a of the manhole body 1 is
The scum is prevented from adhering to the side surfaces of the pumping line 25 and the scum adhering to the side surface is prevented from being solidified.

Since the discharge pipe 30 is branched from the pressure feed pipe 25, the air in the pressure feed pipe 25 is discharged from the water feed pipe 25 when the submersible pump 11 is started up, thereby avoiding the air lock of the submersible pump 11. . That is, it also functions as an air vent.

The needle valve 58 is provided to adjust the moving speed of the oil between the oil chamber 55 and the oil chamber 48. The adjustment of the moving speed of the oil is performed by operating the lever 58a to adjust the throttle of the needle valve 58. With this adjustment, it is possible to roughly set the time from the start of discharging the sewage through the opening 41 of the valve 40 to the stop of the discharge of the sewage.

Further, the ball valve 34 is provided for checking the sprinkling unit U. That is, the ball valve 34 is closed by the lever 34a,
The watering unit U is checked after the sewage is prevented from passing through the ball valve 34.

Further, in the above embodiment, the force received by the water receiving portion (sprinkler plate 50) from the sewage is transmitted to the valve body (ball 43) at the open position by the oil passage including the tube 56 and the like. The means for transmitting force from the receiving part to the valve body is an oil passage,
It is not limited to a liquid channel. For example, a link mechanism or an air passage may be used.

[0056]

The scum removing device for a sewage tank according to the present invention has the following effects. (1) Since the discharge pipe discharges sewage by the driving force of the pump, a simple configuration can be achieved without the need to add a special power source or a special power source. Further, since scum can be removed near the pump starting water level to which scum is most likely to adhere, it is effective to prevent scum from adhering near the pump starting water level. Therefore, corrosion of the sewage tank is also prevented. (2) Since the opening for discharging the sewage toward the water receiving portion does not need to have a small opening area, clogging with filth can be prevented. Therefore, manual cleaning work is not required. That is, the maintenance cost of the sewage tank can be reduced. (3) Since the valve which opens and closes in response to the collision of the wastewater with the water receiving portion is provided, the wastewater can be ejected from the discharge pipe for a certain period of time after the pump is started. Then, after the sewage is discharged from the discharge pipe as necessary for scum removal, the driving force of the pump can be used only for discharging the sewage from the sewage tank.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a manhole.

FIG. 2 is a view of a watering unit and the like. (A) is a partial cross-sectional side view of the water sprinkling unit and its peripheral members, and (b) is a partial cross-sectional view as viewed from the arrow B of (a).

FIG. 3 is a cross-sectional view of a ball valve and the like, and is a view for showing the operation of the scum removing device in stages by (a) to (d).

FIG. 4 is a sectional view taken along line AA of FIG. 1;

[Explanation of symbols]

 U Watering unit W1 Pump start water level W2 Pump stop timer operation water level W3 Pump automatic stop water level 1 Manhole body 1a Inner wall 2 Bottom plate 3 Crushed stone foundation 4 Manhole cover 10 Manhole 11 Submersible pump 11a Suction port 12 Pressure pipe 13 Check valve 14 Ball Valve 15 Discharge pipe 15a Bifurcated pipe 15b Straight pipe 21 Chain 22 Bubble level gauge 25 Pumping pipe 30 Discharge pipe 32 Branch pipe 34 Ball valve 34a Lever 36 Connection pipe 40 Valve 41 Opening 42 Valve room 43 Ball 44 Housing 45 Guide 46 Side wall 46a Opening 47 Diaphragm 48 Oil chamber 50 Sprinkler plate 50a Upper surface 50b Lower surface 51 Cylinder 52 Piston 53 Lid 53a Opening 54 Diaphragm 55 Oil chamber 56 Tube 57 Strut 58 Needle valve 58a Lever

Claims (10)

[Claims] A pump for pumping sewage from a sewage tank and discharging the sewage to the outside of the sewage tank; a valve and an opening; and a part of the sewage pumped by the pump through the opening to the sewage tank. A discharge pipe for discharging water into the inside of the sewage tank, and the pump starts to start when the level of the sewage in the sewage tank reaches a predetermined pump start-up water level. The water receiving portion is provided at a position higher than the starting water level in the tank, the water receiving portion is provided at a position higher than the starting water level in the sewage tank, and the discharge pipe collides with the water receiving portion from the opening. The water receiving portion reflects and diffuses the sewage discharged from the opening, and in response to the sewage colliding with the water receiving portion, the valve body of the valve is discharged. Sewage that shifts from an open position to open the discharge line to a closed position to close the discharge line Use scum removal device. 2. The scum removing device for a sewage tank according to claim 1, wherein said water receiving portion diffuses said sewage discharged from said opening in a substantially horizontal direction. 3. The scum removing device for a sewage tank according to claim 2, wherein the water receiving portion diffuses the sewage discharged from the opening in substantially the entire circumferential direction with respect to a vertical axis. 4. The water supply device according to claim 1, wherein the opening is provided upward, the water receiving portion has a downward surface, and the sewage discharged from the opening is reflected by the downward surface. A scum removing device for a sewage tank according to any one of the preceding items. 5. The scum removing device for a sewage tank according to claim 4, wherein the downward surface of the water receiving portion is a concave curved surface. 6. The water receiving part and the valve are connected by a liquid path, and when the water receiving part receives the collision of the sewage, the hydraulic fluid in the liquid path is drained from the water receiving part side to the water receiving part. By the hydraulic pressure of the working fluid that is pressure-fed to the valve side and pressure-fed to the valve side,
The scum removal device for a sewage tank according to any one of claims 1 to 5, wherein the valve body that retreats to a position outside the flow path in the valve is pushed toward the flow path. 7. The valve according to claim 1, wherein the valve element is a ball.
A scum removal device for a sewage tank according to any one of the above items. 8. The scum removal apparatus for a sewage tank according to claim 1, wherein the opening is an outlet-side opening of the valve. 9. A distance from the opening to the water receiving portion,
The scum removing device for a sewage tank according to any one of claims 1 to 8, wherein the scum removing device is longer than a diameter of the opening. 10. The sewage tank according to claim 1, wherein the discharge pipe branches from a pressure feed pipe interposed between the pump and a discharge pipe of the sewage tank. Scum removal device.