JP3970472B2 - Scum removal device for sewage tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a scum removal device for removing scum generated in a sewage tank, and in particular, scum removal that removes scum using pumped water from a pump for pumping up sewage and discharging it out of the sewage tank. Relates to the device.
[0002]
[Prior 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, piping, cables, etc. due to the organic substances and oil components of the sewage. If the scum adheres to, for example, a float type water level gauge, the water level gauge malfunctions. If left untreated, scum generates hydrogen sulfide that is harmful and gives off an odor. Since hydrogen sulfide is corrosive, it causes corrosion of the sewage tank. When the scum starts to adhere to the inner wall surface of the sewage tank, the scum further adheres to the scum tank.
[0003]
Conventionally, in many manholes, in order to wash away such scum, regular cleaning with a high pressure washer was performed. Moreover, the scum may be removed by circulating the sewage in the sewage tank. Note that it is conceivable to use a flush valve (for example, see JP-A-4-34579), an electric valve, and a mixer that utilize the ejector effect for circulating the sewage.
[0004]
[Problems to be solved by the invention]
However, the conventional scum removal method has the following problems.
[0005]
If regular cleaning is performed with a high pressure washer, naturally a high pressure washer is required. In addition, manual cleaning is required for regular cleaning. Thus, the cost and labor for cleaning are large.
[0006]
Moreover, the scum that adheres firmly may not be removed only by circulating the sewage in the sewage tank. In particular, the scum is likely to adhere to the vicinity of the pump starting water level, and it is necessary to generate a strong circulation in order to sufficiently remove even the scum adhering to and accumulating there. To that end, the power source for circulation must be large.
[0007]
Moreover, if the sewage in the sewage tank is circulated more than necessary, the driving force of the pump that should be used to discharge the sewage to the outside of the manhole is essentially wasted.
[0008]
It is an object of the present invention to provide a scum removing device that can sufficiently remove scum that tends to accumulate in the sewage tank, particularly in the vicinity of the pump activation water level.
[0009]
Another object of the present invention is to provide a scum removing device that can prevent waste of driving force of the pump as much as possible when removing scum.
[0010]
[Means for Solving the Problems]
  In order to solve the above problems, a scum tank scum removing device according to the present invention comprises a pump for pumping up sewage from a sewage tank and discharging it to the outside of the sewage tank, and a part of the sewage pumped up by the pump. A discharge pipe for discharging into the sewage tank, a valve is provided in the discharge pipe, and the pump starts when the sewage water level in the sewage tank reaches a predetermined pump start water level, The valve includes a float, and the float responds to a decrease in the level of sewage in the sewage tank caused by activation of the pump, and the valve body of the valve opens the discharge pipe by the reaction of the float. Transition from the open position to the closed position that closes the discharge pipeThe valve body is provided with a hook interlocked with the float, and when the sewage water level in the sewage tank is the pump activation water level, the valve body attempts to shift to the closed position by the flow of sewage in the discharge pipe. When the hook is locked at the opening position and the water level of the sewage in the sewage tank is lower than a predetermined water level lower than the pump activation water level, the locking of the hook to the valve body is released.(Claim 1). According to such a configuration, the discharge pipe is closed after a certain amount of sewage has been discharged from the discharge pipe since the start of the pump. Further, the sewage is discharged from the discharge pipe only during the period from the start of the pump until the sewage water level drops to a constant water level. Further, the level of sewage is detected by the float, and the discharge pipe is controlled to open and close without using electrical control or the like.
[0013]
In the scum removing device for a sewage tank, the valve body may be a ball (claim 2).
[0016]
  In the sewage tank scum removing device, the discharge pipe may be configured to discharge sewage in the vicinity of the pump activation water level (Claim 3). According to such a configuration, strong sewage swirl occurs near the pump starting water level where scum is most likely to adhere and accumulate.
[0017]
  In the sewage tank scum removing device, the discharge pipe may be branched from a pumping pipe interposed between the pump and the discharge pipe of the sewage tank (Claim 4). According to such a configuration, the air of the pressure feeding pipe can be extracted from the discharge pipe when the pump is started.
[0018]
  In the sewage tank scum removing device, the discharge pipe may be configured to discharge sewage toward the inner wall surface of the sewage tank (Claim 5). According to this configuration, the sewage from the discharge pipe collides with the inner wall surface of the sewage tank with a strong momentum.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a longitudinal sectional view of the manhole 10. A scum removing device according to an embodiment of the present invention is applied to the manhole 10. The manhole 10 mainly includes a bottom plate 2 placed on the crushed stone foundation 3, a cylindrical manhole main body 1 attached on the bottom plate 2, and a manhole cover 4 for closing the upper end opening of the manhole main body 1. It consists of Manhole 10 is buried in the ground.
[0021]
A sewage inflow pipe 5 is connected to the manhole 10, and sewage as sewage is supplied from the sewage inflow pipe 5 into the manhole 10.
[0022]
The manhole 10 is provided with a piping system for pumping up and discharging sewage. The piping system mainly includes a submersible pump 11, a pressure feeding pipe 12, a check valve 13, a gate valve 14, a discharge pipe 15, and the like. Although the submersible pump 11, the pressure feed pipe 12, the check valve 13, and the gate valve 14 are arranged symmetrically by two, members having the same reference numerals have the same structure. The main flow passage is formed by the submersible pump 11, the pressure feed pipe 12, the check valve 13, the gate valve 14, and the discharge pipe 15.
[0023]
The discharge pipe 15 is constituted by connecting a forked pipe 15a and a straight pipe 15b, two gate valves 14 are connected to the forked pipe 15a, and sewage passing through both gate valves 14 passes through the straight pipe 15b. Can flow out to the outside.
[0024]
The submersible pump 11 is installed near the bottom of the manhole 10. The submersible pump 11 is provided with a suction port 11a at the bottom thereof, and the sewage sucked from the suction port 11a is pumped to the pumping tube 12. The pumped sewage flows through the discharge pipe 15 and is discharged outside the manhole 10.
[0025]
A chain 21 hangs down 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, and a full water warning float switch 23 is attached to the middle part of the chain 21.
[0026]
Further, a discharge pipe 30 for discharging dirty water from the tip branches off from the side surface of the pressure feed pipe 12. The discharge pipe 30 is a main constituent member of the scum removing device.
[0027]
W1 indicates a pump activation water level at which the submersible pump 11 starts activation. Scum tends to accumulate particularly near the pump starting water level. In the manhole 10 as shown in FIG. 1, the scum is particularly likely to adhere to the vicinity of the pump starting water level on the inner wall surface 1 a of the manhole body 1.
[0028]
W2 is a pump stop timer operating water level at which a timer that measures the time until the submersible pump 11 is stopped starts operating.
[0029]
W3 is a pump automatic stop water level indicating the level of sewage when the submersible pump 11 is stopped.
[0030]
W4 is the full warning level. When the sewage water level reaches the full water warning water level W4, the full water warning float switch 23 is activated to notify a control device (not shown) that the sewage has reached the full water level.
[0031]
FIG. 2 is a longitudinal sectional view of the pumping tube 12 and the discharge tube 30 in the vicinity of a branch point where the discharge tube 30 branches from the pumping tube 12. 3 is a cross-sectional view taken along the line AA in FIG. 1, but the sewage inflow pipe 5 is omitted.
[0032]
The discharge pipe 30 branches off from the vicinity of the pump activation water level W1 on the side surface of the pressure feed pipe 12, and extends in the horizontal direction to the vicinity of the inner wall surface 1a of the manhole main body 1. Therefore, the discharge port 30a at the tip of the discharge pipe 30 is located in the vicinity of the inner wall surface 1a of the manhole body 1. As shown in FIG. 3, the discharge port 30a faces the inner wall surface 1a.
[0033]
Next, the operation of the discharge pipe 30 shown in FIGS.
[0034]
When sewage flows into the manhole 10 from the sewage inflow pipe 5 and the sewage water level reaches the pump activation water level W1, a control device (not shown) that inputs an output signal from the bubble-type water level gauge 22 detects that. The start command is issued to the submersible pump 11. The submersible pump 11 starts to start, and the sewage sucked from the suction port 11a is pumped to the pumping pipe 12. The pumped sewage is discharged to the outside through the discharge pipe 15.
[0035]
On the other hand, the sewage flowing through the pressure feeding pipe 12 also branches into the discharge pipe 30. Then, the sewage is guided to the discharge pipe 30 and discharged from the discharge port 30a at the tip of the discharge pipe 30. The discharge port 30a is configured to perform a nozzle function, and sewage is accelerated and ejected from the discharge port 30a. The discharged sewage collides with the inner wall surface 1a of the manhole 10. This collision point is in the vicinity of the pump starting water level W1 on the inner wall surface 1a, and is the height at which scum is most likely to adhere and accumulate. The sewage discharged from the discharge port 30a ishes away the scum adhering to the inner wall surface 1a. The ejected sewage not only flushes the scum adhering to the inner wall surface 1a, but also circulates the sewage in the manhole 10 due to its momentum. The discharge port 30a is located in the vicinity of the pump starting water level W1, and since sewage is discharged in the vicinity of the pump starting water level W1, the sewage swirls strongly in the vicinity of the pump starting water level W1. That is, the strongest circulation occurs at the water level where scum is most likely to accumulate. Therefore, the scum accumulated near the pump activation water level W1 is dispersed and hardly adheres to the inner wall surface 1a. Further, scum that has already adhered near the pump activation water level W1 is also easily removed.
[0036]
The discharge port 30a may be positioned above the pump activation water level W1, or may be positioned below the pump activation water level W1. When the discharge port 30a is positioned above the pump activation water level W1, sewage is jetted in the air, and thus strongly collides with the inner wall surface 1a. Therefore, it is advantageous for cleaning the scum adhering to the inner wall surface 1a. Further, when the discharge port 30a is positioned below the pump activation water level W1, since the sewage is injected in the sewage, strong swirling of the sewage can be generated in the vicinity of the pump activation water level W1. The discharge port 30a does not necessarily have to face the inner wall surface 1a.
[0037]
When the submersible pump 11 continues to pump the sewage in the manhole 10 to the outside, the sewage water level reaches the pump stop timer operating water level W2. Then, the control device learns 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 since the timer operation, the control device issues a stop command to the submersible pump 11. At this time, the sewage water level substantially coincides with the pump automatic stop water level W3.
[0038]
Since the discharge pipe 30 is branched from the pressure feed pipe 12, the air in the pressure feed pipe 12 is discharged from here when the submersible pump 11 is started, and the air lock of the submersible pump 11 is avoided. That is, it also functions as an air vent.
[0039]
Next, a second embodiment of the scum removing device according to the present invention will be described with reference to FIGS. FIG. 4 is a side view of the discharge pipe 40 constituting the scum removing device. Unlike the discharge pipe 30 of the first embodiment shown in FIGS. 1 to 3, the discharge pipe 40 is provided with a valve 50 in the middle thereof. Other configurations are the same as those of the discharge pipe 30 of the first embodiment. That is, the discharge pipe 40 is also branched from the pumping pipe 12 for pumping the sewage from the submersible pump 11 to the outside. The discharge pipe 40 branches off from the vicinity of the pump activation water level W1 on the side surface of the pressure feed pipe 12, and extends in the horizontal direction to the vicinity of the inner wall surface 1a of the manhole main body 1. Therefore, the discharge port 40a at the tip of the discharge pipe 40 is located in the vicinity of the inner wall surface 1a of the manhole body 1. The discharge port 40a is not necessarily so, but is directed to the inner wall surface 1a, and the sewage ejected from the discharge port 40a collides with the inner wall surface 1a of the manhole 10.
[0040]
In the second embodiment, the valve 50 is configured to open and close the discharge pipe 40 in response to a change in the state of sewage in the manhole 10 caused by the activation of the submersible pump 11. The change in the state of sewage here means a change in the level of sewage in the manhole 10, a change in the pressure of sewage at a predetermined location in the manhole 10, a change in the flow rate of sewage at a predetermined location in the manhole 10, etc. However, in the second embodiment, in particular, the valve 50 is configured to respond to a decrease in the level of sewage in the manhole 10 caused by the activation of the submersible pump 11.
[0041]
A valve 50 provided in the middle of the discharge pipe 40 includes a float 51. The float 51 is fixed to an arm 52, and the arm 52 can be rotated with a valve casing 53 as a fulcrum. Therefore, the float 51 can be rotated between a hanging posture (S1) that hangs right below the valve casing 53 and a horizontal posture (S2) that is located just beside the valve casing. The float 51 cannot be raised beyond the horizontal posture (S2) by a stopper (not shown). When the level of sewage in the manhole 10 is a low water level such as W5 in FIG. 4, the float 51 is in the hanging posture (S1). Then, as the sewage water level rises, the float rises, and when the sewage water level reaches the pump activation water level W1, the float 51 takes a horizontal posture (S2).
[0042]
5A and 5B are cross-sectional views of the valve 50, where FIG. 5A is a longitudinal cross-sectional view, FIG. 5B is a cross-sectional view taken along line B1-B1 in FIG. 5A, and FIG. 5C is a cross-sectional view taken along line B2-B2 in FIG. FIG. In the valve casing 53, a ball 54 as a valve body formed by covering a steel ball with rubber is incorporated. In the valve casing 53, a first chamber 55 positioned in the flow path 40b of the discharge pipe 40 and a second chamber 56 positioned away from the flow path 40b below the flow path 40b are formed. . The ball 54 moves between the first chamber 55 and the second chamber 56. A seating surface 57 for seating the ball 54 is formed in the first chamber 55. When the ball 54 is seated on the seating surface 57, the flow path 40b is closed.
[0043]
An arm 52 is rotatably supported on the valve casing 53 by a bearing 58. One end side of the arm 52 is bent in a semicircular shape in the second chamber 56 to form a hook 59. A float 51 is attached to the other end side of the arm 52.
[0044]
The state shown in FIG. 5 is a state in which the float 51 is in the horizontal posture (S2). The ball 54 in the second chamber 56 is prevented from moving to the first chamber 55 by the hook 59, and the flow path 40b is in an open state.
[0045]
FIG. 6 is a longitudinal sectional view of the valve 50 showing various states of the valve 50. The operation of the valve 50 will be described with reference to this figure.
[0046]
If the level of sewage in the manhole 10 is the low water level W5, the float 51 is in the hanging position (S1) as shown in (a). At this time, although the hook 59 does not restrain the movement of the ball 54, the submersible pump 11 is in a stopped state and no sewage flows through the flow path 40b, so the ball 54 is positioned in the second chamber 56. . That is, the ball 54 is in an opening position where the flow path 40b is opened.
[0047]
When sewage flows into the manhole 10 from the sewage inflow pipe 5 and the level of sewage rises, the position of the float 51 gradually rises. When the sewage water level reaches the pump activation water level W1, the float 51 is in the horizontal posture (S2) as shown in (b). Further, since the sewage water level has reached the pump activation water level W1, the submersible pump 11 is activated and the sewage flows out to the flow path 40b. At this time, the valve 50 may be submerged in dirty water. The sewage is ejected from the discharge port 40a at the tip of the discharge pipe 40, and the scum adhering to the inner wall surface 1a of the manhole 10 is washed away, and at the same time, the sewage in the manhole 10 is circulated. Since the discharge port 40a is located in the vicinity of the pump starting water level W1, strong circulation occurs particularly in the vicinity of the pump starting water level W1.
[0048]
On the other hand, in a state where sewage is flowing in the flow path 40b, the ball 54 tends to float from the state indicated by the phantom line in FIG. However, the ball 54 is locked by the hook 59 and cannot move to the first chamber 55. That is, the ball 54 is locked in the state shown by the solid line in FIG.
[0049]
When the sewage in the manhole 10 is discharged to the outside by the operation of the submersible pump 11, the level of the sewage gradually decreases and the float 51 is also lowered. Then, when the float 51 is lowered to some extent as shown in (c), the locking of the ball 54 by the hook 59 is released, and the ball 54 is lifted by the flow of the flow path 40b and moves to the first chamber 55. Then, the ball 54 is seated on the seating surface 57 and closes the flow path 40b. That is, the ball 54 comes to the closed position indicated by the solid line in (c). Therefore, sewage is not ejected from the discharge port 40a at the tip of the discharge pipe 40. As a result, the driving force of the submersible pump 11 can be used only for discharging the sewage to the outside.
[0050]
If the sewage is further discharged and the water level of the sewage falls in the manhole 10, the submersible pump 11 stops. Then, the ball 54 falls from the first chamber 55 to the second chamber 56, and the ball 54 comes to the open position as shown by the solid line in (d).
[0051]
By such a series of operations of the valve, the sewage can be ejected from the discharge pipe 40 only during the period from the start of the submersible pump 11 until the sewage water level drops to a certain level. That is, after the sewage is ejected from the discharge pipe 40 enough to remove the scum, the driving force of the submersible pump 11 can be used only for discharging the sewage from the manhole 10. Thus, the driving force of the submersible pump can be used effectively. The degree to which the level of sewage drops can be adjusted by the height at which the valve 50 is attached to stop the discharge of sewage from the discharge pipe 40.
[0052]
In the second embodiment, the discharge port 40a is configured to be positioned in the vicinity of the pump activation water level W1, but the height of the discharge port 40a is significantly lower than the pump activation water level W1, for example, the pump activation water level W1. And the pump automatic stop water level W3 may be arranged at a middle height position. In order for the discharge port 40a to come to a height position that is greatly below the pump activation water level W1, for example, L-shaped curved portions 40c and 40d may be formed in the middle of the discharge pipe 40 as shown in FIG. . In this way, the sewage circulation in the vicinity of the pump starting water level W1 cannot be particularly strengthened, but the entire sewage can be circulated. Moreover, even if comprised in this way, the effect that a sewage can be ejected from the discharge pipe 40 only from the time of starting of the submersible pump 11 until a sewage water level falls to a fixed water level is FIG. This occurs in the same manner as the scum removing device shown in FIG.
[0053]
Next, a third embodiment of the scum removing device according to the present invention will be described with reference to FIGS. FIG. 8 is a side view of the discharge pipe 60 constituting the scum removing device. Unlike the discharge pipe 30 of the first embodiment shown in FIGS. 1 to 3, the discharge pipe 60 is provided with a valve 70 in the middle thereof. Other configurations are the same as those of the discharge pipe 30 of the first embodiment. That is, the discharge pipe 60 is also branched from the pumping pipe 12 for pumping the sewage from the submersible pump 11 to the outside. The discharge pipe 60 branches off from the vicinity of the pump activation water level W1 on the side surface of the pressure feed pipe 12, and extends in the horizontal direction to the vicinity of the inner wall surface 1a of the manhole main body 1. Therefore, the discharge port 60a at the tip of the discharge pipe 60 is located in the vicinity of the inner wall surface 1a of the manhole body 1. The discharge port 60a faces the inner wall surface 1a, and the sewage ejected from the discharge port 60a collides with the inner wall surface 1a of the manhole 10.
[0054]
In the third embodiment, the valve 70 is configured to open and close the discharge pipe 40 in response to a change in the state of sewage in the manhole 10 caused by the activation of the submersible pump 11. In the third embodiment, in particular, the valve 70 is configured to respond to a change in pressure in the discharge pipe 60 caused by the activation of the submersible pump 11.
[0055]
FIG. 9 is a longitudinal sectional view of the valve 70. In the valve casing 73, a steel ball 74 as a valve body is incorporated. Further, in the valve casing 73, a chamber 75 located in the flow path 60b of the discharge pipe 60 and a standby part 76 that is below the flow path 60b and waits at a position outside the flow path 60b of the ball 74 are formed. ing. The ball 74 moves between the chamber 75 and the standby unit 76. The chamber 75 is formed with a seating surface 77 on which the ball 74 is seated. When the ball 74 is seated on the seating surface 77, the flow path 60b is closed.
[0056]
A first oil chamber 81 and a second oil chamber 84 are formed below the standby unit 76. The first oil chamber 81 is formed as a space surrounded by a rubber diaphragm 82 as a moving body and a cup-shaped bottom wall portion 83. In the state of FIG. 9, the diaphragm 82 is at a lower position that is substantially in close contact with the bottom wall portion 83, and the volume of the first oil chamber 81 is substantially zero.
[0057]
The second oil chamber 84 is below the first oil chamber 81, and is formed as a space surrounded by the ceiling wall portion 86, the side wall portion 87, and the rubber film 85.
[0058]
The first oil chamber 81 and the second oil chamber 84 are communicated with each other through a communication hole 88. The first oil chamber 81, the second oil chamber 84, and the communication hole 88 are filled with oil. The oil can move between the first oil chamber 81 and the second oil chamber 84 through the communication hole 88. The communication hole 88 is provided with an oil amount adjusting bolt 89 so that the resistance applied to the oil passing through the communication hole 88 can be adjusted.
[0059]
FIG. 10 is a longitudinal sectional view of the valve 70 showing various states of the valve 70. The operation of the valve 70 will be described with reference to this figure.
[0060]
If the level of sewage in the manhole 10 is at a low level, the submersible pump 11 is in a stopped state, and sewage does not flow into the flow path 60b. Most of the oil is sucked into the second oil chamber 84 by the tension of the rubber film 85, and the volume of the first oil chamber 81 becomes almost zero as shown in (a). The diaphragm 82 is in the lower position, and the ball 74 is located in the standby unit 76. That is, the ball 74 is in the standby position.
[0061]
When sewage flows from the sewage inflow pipe 5 into the manhole 10, the sewage level rises, and when the sewage level reaches the pump activation level W1, the submersible pump 11 is activated and sewage flows out to the flow path 60b. The sewage is ejected from the discharge port 60a at the tip of the discharge pipe 60, and the scum adhering to the inner wall surface 1a of the manhole 10 is washed away, and at the same time, the sewage in the manhole 10 is circulated. Since the discharge port 40a is located in the vicinity of the pump starting water level W1, strong circulation occurs particularly in the vicinity of the pump starting water level W1.
[0062]
On the other hand, a negative pressure is generated in the chamber 75 in a state where sewage flows through the flow path 60b. The diaphragm 82 is lifted to a state as shown in (b) by this negative pressure, and the ball 74 is lifted to the diaphragm 82. Note that when the diaphragm 82 is lifted, the movement of oil from the second oil chamber 84 to the first oil chamber 81 is accompanied. When the oil passes through the communication hole 88, the oil is subjected to resistance by the oil amount adjusting bolt 89. Therefore, the diaphragm 82 is not lifted rapidly and is lifted relatively slowly.
[0063]
When the diaphragm 82 is further lifted and reaches the upper position as shown in (c), the ball 74 rises to the chamber 75 due to the negative pressure of the chamber 75. Then, as shown by the solid line in (c), the ball 74 is seated on the seating surface 77 and closes the flow path 60b. That is, the ball 74 comes to the closed position. Therefore, sewage is not ejected from the discharge port 60a. As a result, the driving force of the submersible pump 11 can be used only for discharging the sewage to the outside.
[0064]
When the ball 74 closes the flow path 60b, the diaphragm 82 is gradually pushed down by the internal pressure of the chamber 75 to return to the lower position. When the submersible pump 11 stops, the ball 74 falls from the chamber 75 to the standby unit 76 and returns to the standby position as shown in (d).
[0065]
By such a series of operations of the valve 70, the sewage can be ejected from the discharge pipe 60 only for a predetermined time from the start of the submersible pump 11. That is, after the sewage is ejected from the discharge pipe 60 enough to remove the scum, the driving force of the submersible pump 11 can be used only for discharging the sewage from the manhole 10. Thus, the driving force of the submersible pump 11 can be used effectively. It should be noted that the time for discharging the sewage from the discharge pipe 60 can be adjusted by the oil amount adjusting bolt 89.
[0066]
In the third embodiment, the valve 70 is positioned above the pump starting water level W1, and the discharge port 60a is also positioned above the pump starting water level W1. Therefore, the sewage is injected in the air and strongly collides with the inner wall surface 1a. Therefore, it is advantageous for cleaning the scum adhering to the inner wall surface 1a. However, the discharge port 40a may be configured to be at a height position below the pump activation water level W1. In order to configure in this way, an L-shaped curved portion may be formed in the middle of the discharge pipe 60, for example, as in FIG.
[0067]
In the above-described embodiment, a pressure detection type valve using negative pressure is shown, but it may be configured as a water level detection type using a flow (turbulent flow) in the pipe.
[0068]
【The invention's effect】
The scum removing device for a sewage tank according to the present invention has the following effects.
(1) If the discharge pipe is configured to discharge sewage in the vicinity of the pump starting water level, there is no need to add a special power source or the like, and strong sewage circulation near the pump starting water level where scum is most likely to adhere. Can be generated. Therefore, it is effective to prevent the scum from adhering to the vicinity of the pump starting water level. Moreover, it becomes easy to remove the attached scum.
(2) If a valve that opens and closes in response to changes in the state of sewage is provided, after discharging sewage from the discharge pipe as much as necessary to remove scum, the driving force of the pump is used only for discharging from the sewage sewage tank. Will be able to.
(3) When a valve that responds to a drop in the water level is provided, the sewage can be discharged from the discharge pipe only until the sewage water level drops to a constant water level.
(4) If the float opens and closes the valve by responding to the drop in the water level, the sewage is discharged from the discharge pipe only until the sewage level drops to a certain level without using electrical control. Can be discharged.
(5) When a valve that responds to the negative pressure in the discharge pipe is provided, sewage can be ejected from the discharge pipe for a certain period of time from the start of the submersible pump.
(6) When a valve is configured using a moving body that is displaced by the negative pressure generated in the discharge pipe and a ball placed thereon, the submersible pump can be started from the start without using electrical control. Sewage can be ejected from the discharge pipe for a certain period of time.
(7) When the discharge pipe is configured to branch from the pressure feed pipe, the discharge pipe functions as an air vent for avoiding an air lock when the pump is started.
(8) If the sewage from the discharge pipe is discharged toward the inner wall surface of the sewage tank, the scum adhering to the inner wall surface can be efficiently washed away. In this case, it is not necessary to add special equipment such as a power source, and no manual cleaning work is required.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a manhole.
FIG. 2 is a vertical cross-sectional view of a pressure feed pipe and a discharge pipe in the vicinity of a branch point where the discharge pipe branches from the pressure feed pipe.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
FIG. 4 is a side view of a discharge pipe.
5A and 5B are cross-sectional views of the valve, wherein FIG. 5A is a longitudinal cross-sectional view, FIG. 5B is a cross-sectional view taken along line B1-B1 in FIG. 5A, and FIG. 5C is a cross-sectional view taken along line B2-B2 in FIG. It is sectional drawing.
FIG. 6 is a longitudinal sectional view of the valve for explaining the operation of the valve in (a) to (d).
FIG. 7 is a side view of the discharge pipe.
FIG. 8 is a side view of the discharge pipe.
FIG. 9 is a longitudinal sectional view of a valve.
FIG. 10 is a longitudinal sectional view of the valve for explaining the operation of the valve in (a) to (d).
[Explanation of symbols]
S1 Hanging position
S2 horizontal posture
W1 Pump start water level
W2 Pump stop timer operating water level
W3 Pump automatic stop water level
W4 Full water warning level
1 Manhole body
1a Inner wall
2 Bottom plate
3 Crushed stone foundation
4 Manhole cover
5 Sewage inflow pipe
10 Manhole
11 Submersible pump
11a Suction port
12 Pumping tube
13 Check valve
14 Gate valve
15 discharge pipe
15a Two-way pipe
15b straight pipe
21 chains
22 Bubble type water level gauge
23 Float switch for full water alarm
30 Discharge pipe
30a Discharge port
40 Discharge pipe
40a Discharge port
40b flow path
40c, 40d music part
50 valves
51 Float
52 arms
53 Valve casing
54 balls
55 Room 1
56 Room 2
57 Seating surface
58 Bearing
59 hook
60 Discharge pipe
60a Discharge port
60b flow path
70 valves
73 Valve casing
74 balls
75 rooms
76 Standby section
77 Seating surface
81 1st oil chamber
82 Diaphragm
83 Bottom wall
84 Second oil chamber
85 Rubber membrane
86 Ceiling wall
87 Side wall
88 communication hole
89 Oil level adjustment bolt

Claims (5)

A pump for pumping up the sewage in the sewage tank and discharging it to the outside of the sewage tank; and a discharge pipe for discharging a part of the sewage pumped up by the pump into the sewage tank,
A valve is provided on the discharge pipe;
The pump starts when the sewage water level in the sewage tank reaches a predetermined pump start water level,
The valve has a float,
The float responds to a decrease in the level of sewage in the sewage tank caused by the activation of the pump;
Due to the response of the float, the valve body of the valve shifts from an open position for opening the discharge pipe to a closed position for closing the discharge pipe ,
The valve includes a hook interlocking with the float;
When the level of sewage in the sewage tank is the pump starting level, the hook is locked at the open position by the hook, the valve body that is about to move to the closed position by the flow of sewage in the discharge pipe,
The scum removing device for a sewage tank, wherein when the sewage water level in the sewage tank is equal to or lower than a predetermined water level lower than the pump activation water level, the hook is released from being locked to the valve body. The scum removing device for a sewage tank according to claim 1 , wherein the valve body is a ball. The scum removing device for a sewage tank according to claim 1 or 2 , wherein the discharge pipe discharges sewage in the vicinity of the pump starting water level. The scum removing device for a sewage tank according to any one of claims 1 to 3 , wherein the discharge pipe branches from a pumping pipe interposed between the pump and a discharge pipe of the sewage tank. The scum removing device for a sewage tank according to any one of claims 1 to 4 , wherein the discharge pipe discharges sewage toward the inner wall surface of the sewage tank.

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