JP2006023196A - Water level detecting device of scum removing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect a water level in two directions of the normal rotation side (the upstream side) and reverse rotation side (the downstream side) of a pipe skimmer. <P>SOLUTION: This device is constituted so that an air pressure source and a pressure switch 12 are connected via a connecting pipe 10 to a support part 17 installed in the pipe skimmer 4; a pair of purge pipes 20 and 21 are supported by the support part 17; a lever 25 having a seal part 26 on the upper end and having a weight on the lower end, is rotatably installed in the support part 17; an overflow part 4c composed of an edge part of its opening part 1a, makes scum sinking and floating under the water surface flow in from the opening part 1a in normal rotation or reverse rotation of the pipe skimmer 4; the tip of one purge pipe sinks under the water level, and blocks up the other purge pipe by a seal part 26; the predetermined depth from the water level is detected by operating the pressure switch 12 when air pressure in the connecting pipe 10 becomes predetermined pressure; and the pipe skimmer 4 is stopped. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a scum removing device attached to a sedimentation basin of a sewage treatment facility, and relates to a water level detection device used when removing scum floating on the sedimentation basin.

  In the sewage treatment facility, the sewage passes through the first settling basin, the aeration tank, and the final settling basin, and the treated water is discharged into the water channel in the treatment plant, and the settled sludge is collected by a flight-type sand scourer. The treated water is discharged from the final sedimentation basin through the in-site water channel into the river. In the first and final sedimentation basins, a scum removing device is provided to collect and discharge floating scum.

  Conventionally, a pipe schema device has been used as a scum removing device that removes scum floating on a settling basin of a sewage treatment plant. An example of this will be described in Patent Document 1. 5A and 5B are a schematic longitudinal side view and a schematic transverse plan view of the conventional scum removing device disclosed in Patent Document 1, and FIGS. 6A and 6B are water level detections of the water level detection device. The first sedimentation basin 1 is a rectangular sedimentation basin with left and right side walls 1a and front and rear side walls 1b provided on the foundation concrete part, and the treated water is passed over the rear side wall 1b. A flow section 1d is provided, and a pond bed 1c is provided with a flight-type sand sinking machine or the like that scrapes the settled sludge. The first sedimentation basin 1 is covered with a lid 1e. The overflow water that has overflowed the treated water overflow section 1d flows into the second sedimentation basin and the like through the water diversion channel 2. The scum removing device 3 attached to the first sedimentation basin 1 collects the scum that floats near the water surface of the first sedimentation basin 1.

  The scum removing device 3 mainly includes a pipe schema 4 and a pressure switch type water level detecting device 5. The tubular pipe schema 4 is provided with a large number of openings 4a, and both ends of the pipe schema 4 are supported in a bridging manner by the bearing portions 4b on the left and right side walls 1a and orthogonal to the flow of the water to be treated. It is arranged horizontally in the direction to do. The pipe schema 4 is provided with a purge pipe 6. When the electric motor 7 is driven, the pipe schema 4 is rotated, and the purge pipe 6 is also rotated together with the pipe schema 4. The open end of the pipe schema 4 that protrudes outside the first sedimentation basin 1 is connected to a dehydrator 15, and the scum S collected by the pipe schema 4 is sent to the dehydrator 15 and separated into treated water and sludge. The The treated water flows down to the second settling basin, and the sludge is conveyed to the sludge treatment device.

  The pressure switch type water level detection device 5 will be described. The purge pipe 6 is a tubular pipe having both ends opened, and is supported by an arm member 8 provided in the pipe schema 4 via a position adjustment member 9. A pressure guiding pipe 10 is connected to one open end 6a of the purge pipe 6, and the other open end 6b is open. A pressure gauge 11, a pressure switch 12, and a blower 13 are connected to the pressure guiding tube 10. The position adjusting member 9 can adjust the length of the purge pipe 6 and the insertion angle of the first settling basin 1 to the water surface, and is fixed after the adjustment. As the pressure guiding pipe 10 in the vicinity of the purge pipe 6, a flexible pipe is used. In addition, the air blower 13 should just be a pressurized air supply means, for example, may be a pump.

  When the open end 6b of the purge pipe 6 is inserted into the water surface and blocked, the air pressure in the purge pipe 6 and the pressure guiding pipe 10 rises, the pressure switch 12 is activated, and an electric signal is output from the pressure switch 12. The control signal is input to the control device 14 and a control signal for controlling the electric motor 7 is output from the control device 14. The control device 14 can be programmed with a procedure for detecting the water level of the first sedimentation basin 1 and can be controlled so that the pressure switch type water level detection device 5 detects the water level intermittently. The blower 13 may also serve as a blower that supplies aeration air supplied to the aeration tank of the sewage treatment facility. In that case, the aeration air is distributed to the water level detection device 5 by using piping. The pressure switch 12 is a differential pressure type pressure switch so as not to be affected by atmospheric pressure fluctuations.

  Next, the operation of the above configuration will be described. First, when the scum removal device 3 (water level detection device 5) is in a standby state, as shown in FIG. 6B, the opening 4a of the pipe schema 4 faces upward, and the open end 6b of the purge pipe 6 is Open to the air. The pressure air supplied to the purge pipe 6 is discharged into the air from the open end 6b, and the pressure gauge 11 indicates zero Pa.

When the electric motor 7 is operated based on the control signal from the control device 14, the pipe schema 4 rotates in the Y direction in FIG. 6B, and about 100 mmH ₂ O (about 980 Pa) from the open end 6b of the purge pipe 6. When the open end portion 6b of the purge pipe 6 reaches the water surface of the first settling basin 1, the overflow portion 4c that is the edge of the opening 4a of the pipe schema 4 is slightly submerged from the water surface. Then, when the pipe schema 4 further rotates and the weir height (distance from the water surface to the open end 6b) A reaches about 45 mm, the floating scum becomes the opening of the pipe schema 4 as shown in FIG. It flows in from 4a. On the other hand, when the open end 6b of the purge pipe 6 is inserted into the water with the rotation of the pipe schema 4, the pressure in the pressure guiding pipe 10 suddenly rises and the pressure switch 12 is activated to control the electric signal. Supplied to the device 14. As a result, the control device 14 outputs a control signal, performs control to stop the operation of the electric motor 7, and stops the rotation of the pipe schema 4.

  On the other hand, the scum floating in the first sedimentation basin 1 flows into the opening 4a beyond the overflow part 4c of the opening 4a of the pipe schema 4, flows into the dehydrator 15, and is separated into sludge and treated water. The When the pipe schema 4 rotates and the open end 6b of the purge unit 6 reaches the water surface, the purge unit 6 is preferably inserted perpendicularly to the water surface, and the open end of the purge pipe 6 When 6b reaches the water surface, the positional relationship is set such that the overflow portion 4c of the opening 4a is positioned substantially on the water surface.

  Further, when the open end portion 6b of the purge pipe 6 is inserted deeper than the water surface, the overflow portion 4c is submerged deeply on the water surface and the weir height A increases, and the scum exceeds the overflow portion 4c and enters the pipe schema 4. Flows in. If the overflow section 4c becomes deeper than necessary, the weir height A becomes too high and the amount of water to be treated flowing into the pipe schema 4 increases, and the subsequent dehydrator 15 is overloaded, which is economical. Not right. Accordingly, the positional relationship between the open end portion 6b of the purge pipe 6 and the overflow portion 4c is adjusted so that the optimum weir height A is set.

  The purge pipe 6 is preferably made of a material that does not corrode due to hydrogen sulfide generated in a sedimentation basin or the like, and is preferably made of a material that does not corrode even if scum or contaminants adhere to it. .

  The water level fluctuates in the sedimentation basin. Therefore, if the water level detection by the water level detection device 5 is performed only once, the weir height due to the fluctuation of the water level becomes too high with time, and the treated water flows into the pipe schema 4 unnecessarily. If the weir height is too shallow, the scum cannot be recovered sufficiently. For this reason, for example, it is desirable to perform water level detection at intervals of 3 to 4 minutes. Briefly explaining this scum removal operation, the pipe schema 4 is set to a position where the scum can be collected, and after 3 to 4 minutes have passed, the pipe schema 4 is rotated in the reverse direction to bring the purge pipe 6 into a standby state. The pipe schema 4 is immediately rotated to detect the water level, and the pipe schema 4 is set to the optimum weir height. In order to cope with the fluctuation of the water level, such standby and water level detection are repeated, and control is performed so that the weir height of the pipe schema 4 is accurately set. The control device 14 stores such a water level measurement program and automatically removes scum.

In the scum removal device described above, the water level is detected by the purge pipe 6 and the weir height of the pipe schema 4 is adjusted, so that the scum is insufficiently recovered or the weir height becomes too high and there is a lot of overflow water. It becomes possible to prevent becoming too uneconomical. Further, the water level is detected by the mechanical configuration, and malfunctions due to insulation failure or the like can be prevented even in a bad environment.
JP 2003-1248 A

  FIG. 7 is a cross-sectional view of an essential part of a modified example of the water level detection device of the conventional scum removing device described above. The purge pipe 6 is attached to the pipe schema 4 via an attachment member 16, and the pipe schema 4 is connected to the forward rotation side ( By rotating to the upstream side, it was possible to detect the water level suitable for removing the scum on the upstream side by inserting the tip of the purge pipe 6 into the water surface. It may be better to detect the water level by rotating to the reverse side (downstream side), and it is necessary to detect the water level in two directions on the forward side and the reverse side of the pipe schema 4. However, conventionally, only water level detection in one direction can be performed, and two water level detection devices are required to perform water level detection in two directions.

  The present invention has been made to solve the above-described problems, and provides a water level detecting device for a scum removing device capable of detecting water levels in two directions on the forward and reverse sides of a pipe schema. With the goal.

  A water level detecting device for a scum removing device according to a first aspect of the present invention is a cylindrical pipe that is provided horizontally and rotatably in a settling basin of a sewage treatment facility, and is provided with an opening for allowing a floating scum to flow in. In a scum removing device having a schema, the scum removing device is attached to a pipe schema and connected to an air pressure source via a pressure guiding pipe, and one end supports the other end of a pair of purge pipes protruding to the forward rotation side and the reverse rotation side of the pipe schema. The support and the overflow part consisting of the edge of the opening of the pipe schema and the tip of one of the purge pipes are submerged under the water surface due to normal rotation or reverse rotation of the pipe schema. A pressure switch that detects a predetermined depth from the water surface of the settling basin, and a lever that is rotatably supported in the support portion and has a seal portion at the upper end and a weight at the lower end. When the pipe schema rotated in the forward side or the reverse side, in which so as to close the sealing portion and the other end opposite the purge tube.

  The water level detection device of the scum removing device according to claim 2 is such that a seal portion is connected to the upper end of the lever via a universal joint.

  According to a third aspect of the present invention, there is provided a water level detecting device for a scum removing device, wherein when the pipe schema is in the neutral position on the forward rotation side and the reverse rotation side, air is allowed to flow out from both purge pipes.

  As described above, according to the first aspect of the present invention, the other end of the pair of purge pipes whose one ends protrude to the forward rotation side and the reverse rotation side of the pipe schema to the support portion connected to the air pressure source via the pressure guide pipe. When the pipe schema is rotated forward or backward, one end of one purge pipe is submerged under the water surface to detect a predetermined depth from the water surface, and the other end of the other purge pipe is The scum is removed by submerging the overflow part of the pipe schema, and the water level when removing the scum on the forward rotation side (upstream side) and when removing the scum on the reverse rotation side (downstream side) Detection can be performed, and the depth of the opening of the pipe schema from the water surface can be controlled to an optimum depth suitable for scum removal. In addition, since the water level detection device is mechanically configured without using any electrical components, it does not malfunction due to insulation failure or the like due to use in a bad environment.

  According to the second aspect of the present invention, the seal portion is connected to the upper end of the lever via a universal joint, so that even if the rotation angle of the lever is small or an error occurs in the rotation angle of the lever, the pipe When the schema is rotated in the forward rotation direction or the reverse rotation side, the other end of the purge pipe on the opposite side can be reliably closed by the seal portion.

  According to claim 3, when the pipe schema is in the neutral position on the forward rotation side and the reverse rotation side, i.e., in the standby state, air is allowed to flow out from both purge pipes to prevent clogging of the purge pipes. These devices can be protected without applying excessive pressure to the equipment upstream of the purge pipe.

Best Embodiment 1
The best mode for carrying out the present invention will be described below with reference to the drawings. 1 (a) to 1 (c) show a standby state of a water level detection device of a scum removal apparatus according to the first embodiment of the present invention, a pipe schema forward rotation side water level detection (upstream scum removal), and a reverse rotation side water level detection. FIG. 2 and FIG. 3 are cross-sectional views of main parts when the water level detection device of the scum removal device is on standby and when detecting the normal rotation side water level, and 17 is a mounting member 16. Is connected to the pressure switch 12 via the pressure guiding tube 10, and is connected to the pressure switch 12 via the flow rate adjusting valve 18 and the pressure reducing valve 19. 13) is connected. One end of the support portion 17 is connected to the other end of the pair of purge pipes 20, 21 projecting to the forward rotation side (upstream side of the treated water) and the reverse side (downstream of the treated water) of the pipe schema 4 via the joints 22, 23. A lever 25 is rotatably supported in the support portion 17 via a rotation shaft 24, a seal portion 26 is provided at the upper end of the lever 25, and a weight 27 is provided at the lower end of the lever 25. It is done.

  Next, the operation of the above configuration will be described. First, in the standby state of the water level detection device (scum removal device) shown in FIGS. 1A and 2, the pipe schema 4 is in the neutral position, and the opening 4 a of the pipe schema 4 is positioned above the support portion. 17 is located immediately above the pipe schema 4. In this case, the lever 25 is positioned in the vertical direction, and the other ends of the purge pipes 20 and 21 are not closed. Therefore, the purge pipes 20 and 21 are both open, and the air from the air pressure source flows out from the tips of the purge pipes 20 and 21 through the support portion 17. The tips of the purge pipes 20 and 21 are separated from the surface of the water to be treated.

  Next, as shown in FIG. 1B and FIG. 3, when the pipe schema 4 is forwardly rotated upstream by the electric motor 7, the overflow section 4 c and the purge pipe formed by the edge of the opening 4 a of the pipe schema 4. One end of 20 is submerged under the surface of the water to be treated. At this time, the support portion 17 also turns, and the seal portion 26 of the rotatable lever 25 closes the other end of the purge pipe 21. The blocking load at this time is obtained by adding the pressure of the air pressure source × the seal area to the load of the weight 27. The turning angle of the lever 25 is smaller than the turning angle of the pipe schema 4. As a result, the pressure in the pressure guiding pipe 10 rises, and when the pressure reaches a predetermined pressure, the pressure switch 12 is activated to detect that the depth of the overflow portion 4c from the water surface has reached the predetermined depth. Stop rotation. The water level detection depth of the purge pipe 20 at this time is H. On the other hand, the scum floating on the upstream side of the pipe scheme 4 of the first settling basin 1 flows into the opening 4a beyond the overflow part 4c of the opening 4a of the pipe schema 4, flows into the dehydrator 15, and sludge. And treated water.

  Next, as shown in FIG. 1 (c), when the pipe schema 4 is reversed to the downstream side by the electric motor 7, the overflow section 4 c formed by the edge of the opening 4 a of the pipe schema 4 and one end of the purge pipe 21 are Sink under the surface of the water to be treated. At this time, the support portion 17 also rotates, and the seal portion 26 of the lever 25 closes the other end of the purge pipe 20. The blocking load at this time is obtained by adding the pressure of the air pressure source × the seal area to the load of the weight 27. As a result, the pressure in the pressure guiding pipe 10 rises, and when the pressure reaches a predetermined pressure, the pressure switch 12 is activated to detect that the depth of the overflow portion 4c from the water surface has reached the predetermined depth. Stop rotation. On the other hand, the scum floating on the downstream side of the pipe scheme 4 of the first sedimentation 1 flows into the opening 4a beyond the overflow part 4c of the opening 4a of the pipe schema 4, flows into the dehydrator 15, and sludge. And treated water.

  In the first embodiment, when the pipe schema 4 is rotated to the normal rotation side (upstream side) to remove the upstream scum, it is also rotated to the reverse rotation side (downstream side) to remove the downstream scum. Even when the water level is detected, the depth of the opening 4a of the pipe schema 4 from the water surface can be controlled to a depth suitable for removing the scum. In addition, since the water level detection device is formed with a mechanical configuration without using electrical components, malfunctions due to poor insulation or the like do not occur even when used under adverse environments. Further, when the pipe schema 4 is in the neutral position on the forward rotation side and the reverse rotation side, that is, in the standby state, air is discharged from both the purge pipes 20 and 21 to prevent the purge pipes 20 and 21 from being clogged. At the same time, no excessive pressure is applied to the air pressure source including the pressure gauge 11, the pressure switch 12, and the blower 13, the pressure reducing valve 19, the flow rate adjusting valve 18, and the like, and these devices can be protected.

Best Embodiment 2
4 (a) to 4 (c) are a main part plan view, a main part longitudinal sectional front view, and a main part cross-sectional plan view of the water level detection device of the scum removing device according to the second embodiment of the present invention in a standby state. 17, a rotating shaft 24 is supported via a support pin 28, and the rotating shaft 24 rotatably supports a lever 25. A flat plate-like seal portion 31 is freely connected through a spherical universal joint 30, and a silicone rubber 32 is attached to the outer surface side of the seal portion 31. A weight 27 is attached to the lower end of the lever 25. On the other hand, the joints 22 and 23 are connected to seal members 33 and 34 attached to the support portion 17.

  Also in the second embodiment, in the standby state, the lever 25 is positioned in the vertical direction, the purge pipes 20 and 21 are in the open state, and air flows out from the tip thereof. Next, when the pipe schema 4 is rotated forward in the upstream direction, the silicone rubber 32 of one seal portion 31 comes into contact with the seal member 34 on the purge pipe 21 side and seals. Further, when the pipe schema 4 is reversed to the downstream side, the silicone rubber 32 of the other seal portion 31 comes into contact with the seal member 33 on the purge pipe 20 side and seals.

  In the second embodiment, the seal portion 31 is freely connected to the upper end of the lever 25 rotatably supported in the support portion 17 via the universal joint 30, and the lever 25 is rotated when the pipe schema 4 is rotated. Even if an error occurs in the rotation angle, the seal portion 31 can reliably seal the seal members 33 and 34 communicating with the purge pipes 20 and 21.

  In the above embodiments, the forward rotation side of the pipe schema 4 is the upstream side of the water to be treated and the reverse side of the pipe schema 4 is the downstream side of the water to be treated. The side may be the upstream side.

It is a block diagram at the time of standby of the water level detection apparatus of the scum removal apparatus by this Embodiment 1 of this invention, pipe schema normal rotation side water level detection, and reverse rotation side water level detection. FIG. 3 is a cross-sectional view of a main part when the water level detection device of the scum removing device according to Embodiment 1 of the present invention is on standby. FIG. 3 is a cross-sectional view of a main part when the water level detecting device of the scum removing device according to Embodiment 1 of the present invention detects the water level on the pipe schema forward rotation side. FIG. 5 is a plan view of relevant parts of a water level detection device of a scum removing device according to a second embodiment, a front view of relevant parts, a longitudinal sectional front view, and a plan view of relevant parts. It is the general | schematic longitudinal side view and the general | schematic cross-sectional plan view of the conventional scum removal apparatus shown by patent document 1. FIG. It is sectional drawing of the water level detection state of the water level detection apparatus of the conventional scum removal apparatus shown by patent document 1, and a standby state. It is principal part sectional drawing of the modification of the water level detection apparatus of the conventional scum removal apparatus shown by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st sedimentation basin 4 ... Pipe schema 4a ... Opening part 4c ... Overflow part 7 ... Electric motor 10 ... Impulse pipe 11 ... Pressure gauge 12 ... Pressure switch 13 ... Blower 14 ... Control apparatus 15 ... Dehydrator 16 ... Mounting member 17 ... support portion 20, 21 ... purge pipe 24 ... rotating shaft 25 ... lever 26, 31 ... seal portion 27 ... weight 30 ... universal joint 33, 34 ... seal member

Claims (3)

  In a scum removing device having a tubular pipe schema provided horizontally and rotatably in a settling basin of a sewage treatment facility and provided with an opening for allowing a floating scum to flow in, the scum removing apparatus is attached to the pipe schema and is supplied with an air pressure source And a support portion that supports the other end of the pair of purge pipes, one end of which protrudes toward the forward rotation side and the reverse rotation side of the pipe schema, and the edge of the opening by the forward or reverse rotation of the pipe schema. A pressure switch that operates when the tip of one overflow pipe and the tip of one of the purge pipes is submerged under the water surface and the air pressure in the pressure guiding pipe reaches a predetermined pressure, and detects a predetermined depth from the water surface of the settling basin; A lever that is supported rotatably in the support part, has a seal part at the upper end and has a weight at the lower end, and is opposite when the pipe schema is rotated forward or reverse. Water level detection apparatus of scum removing apparatus being characterized in that so as to close the sealing portion and the other end of the purge tube.   The water level detecting device for a scum removing device according to claim 1, wherein a seal portion is connected to an upper end of the lever via a universal joint. 3. The water level detecting device for a scum removing device according to claim 1, wherein when the pipe schema is in a neutral position on the forward rotation side and the reverse rotation side, air is allowed to flow out from both purge pipes.

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