JP2013018000A - Sand pumping-up method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sand pumping-up method for collecting sand at low pressure.SOLUTION: The sand pumping method for collecting the sand which has precipitated on the bottom face of a sand sedimentation pond of a sewage treatment facility to a sand collecting pit by injection water, and suctioning and transferring the sand by a sand pumping apparatus is configured to jet pressure water from a sand collecting nozzle for making the sand sedimented on the bottom face of the sand sedimentation pond flow down in that in a drained condition when the water level of the sand sedimentation pond is the bottom level of a central trough.

Description

  The present invention relates to a sand pumping method in which sand (sediment sand) precipitated on a bottom surface of a sand basin of a sewage treatment facility is collected in a sand collecting pit by jet water, and the sand is sucked and transferred by a sand lifting device.

  Conventionally, a storm water settling basin of a storm water pumping station in a sewage treatment facility has been provided with a sand raising device comprising a jet pump for transferring sand deposited on the bottom surface of the storm water settling basin to a predetermined location. The suction port of the jet pump in this sand pumping device is provided so as to be located above the sand collecting pit provided at the lowest position on the bottom surface of the rainwater settling basin. Therefore, when the jet pump is driven, the sand in the sand collection pit is sucked from the suction port and transferred to a predetermined place via the pipe.

  Further, since the sand pumping apparatus using the jet pump uses high-pressure water as a driving source, the power cost is high, and there is a sand pumping apparatus using a spiral blade type sand pump that is inexpensive in power cost.

  In the sand pumping apparatus using this sand pump, the suction port of the sand pump is located near the bottom surface of the sand collecting pit. Therefore, when the sand pump is driven, the sand in the sand collecting pit is sucked from the suction port and transferred to a predetermined place through the pipe.

  When the sand in the sand collection pit is sucked by the above sand lifting device and transferred to a predetermined location, the sand settling at the bottom of the sand settling basin is injected from the sand collecting nozzle when using either a jet pump or a sand lifting pump. It is necessary to flow down with water and collect sand in a sand collecting pit (there is no prior art document).

  If the water level in the settling basin at the start of sand collection using the water jetted from the sand collecting nozzle is at a high level equal to the top of the continuous section provided between the settling pond and the pump well, Not only is it uneconomical, but it also has to overcome the water pressure and move the settling sand to collect the sand, so that the pressure water from the sand collecting nozzle is ejected at a high pressure. Hereinafter, this is referred to as “high pressure sand collection”). High-pressure sand collection not only has a running cost to generate a high pressure, but also has many components. In addition, when high-pressure sand collection is performed, there is a drawback in that sand collection efficiency is also lowered because a part of the sand sinks and floats in the water and then sinks and accumulates again. Furthermore, the generation of sewage mist due to high-pressure water is also a big problem from a hygienic viewpoint.

  Moreover, in the conventional sand raising device, even though sand is present in the sand collecting pit, even if the jet pump or the sand raising pump starts driving, the sand cannot be sufficiently sucked, Therefore, there is a disadvantage that the sand cannot be sufficiently moved.

  This is because when the jet pump or the sand pump starts driving, the suction port is blocked by the sand that has accumulated in the sand collection pit, and neither water nor sand can be sucked.

  Then, this invention is made | formed in order to solve the said fault, and provides the low pressure sand collection method which can perform the low pressure sand collection which ejects the pressure water from a sand collection nozzle by low pressure, and performs sand collection. For the purpose.

  In order to achieve the above-mentioned object, the present invention collects sand deposited on the bottom surface of a sand basin of a sewage treatment facility into a sand collecting pit with jet water, and sucks and transfers the sand by a sand lifting device. In the method, when the water level of the sand basin is in a drainage state existing at the bottom level of the central trough, pressure water is jetted from a sand collecting nozzle for flowing down the sand that has settled on the bottom surface of the sand basin (claim). 1).

  The present invention is characterized in that, in the sanding method, the pressure water jet from the sand collecting nozzle is jetted to the bottom of the sand basin after jetting to the central trough (Claim 2). .

  According to the sand-carrying method of the present invention, in the sand-carrying method of collecting sand in a sand basin into a sand-collecting pit by pressure water jetting from a sand-collecting nozzle, the sand is sucked and transferred by a sand-carrying device. Sand collection can be performed efficiently.

  According to invention of Claim 2, sand collection efficiency improves further.

BRIEF DESCRIPTION OF THE DRAWINGS The sand basin to which the sand lifting method of this invention is applied is shown, Comprising: (a) is the longitudinal cross-sectional view, (b) is a partial top view of (a). FIG. 2 is a cross-sectional view taken along the line II in FIG. It is a flowchart which shows control operation. It is a schematic sectional drawing of a sand basin and a pump well. It is a top view of the left side part of FIG.

  As shown in FIG. 4, in the sand basin 1, as shown in FIG. 4, rainwater flows from one side (left side in FIG. 4) of the sand basin 1, and the rainwater settled and separated from the sand is the other side of the sand basin 1. It is formed so as to flow out to the pump well 30 connected to the sand basin 1 from the side. Further explanation will be given with reference to FIG. 1B. If rainwater flows in from the upper side of the paper in FIG. 1B, the rainwater settled and separated from the sand flows out from the lower side of the paper in FIG. 1B. It becomes.

  The form of the bottom face 1a of the sand basin 1 is to collect sand (not shown) on the bottom face 1a in a sand collecting pit 2 having a flat bottom that is lower than the bottom face 1a provided at a substantially central position of the bottom face 1a. It is formed so that it can be. That is, as shown in FIG. 1 (a), the bottom surface 1a is inclined so that the center line in the rainwater inflow direction is lowest, and as shown in FIG. It is inclined so that the part of the is the lowest. Therefore, when water flows out from a sand collecting nozzle described later on the bottom surface 1a, the sand on the bottom surface 1a is collected in the sand collecting pit 2 as shown by an arrow in FIG. 1 (b). .

  The sand pump 10 is a known submersible pump having spiral blades, and a pump that has been used as a submersible sludge pump in a sewage treatment facility can be used. The sand pump 10 is provided in the sand basin 1 via a discharge pipe 12 and a support 13 with the suction port 11 facing downward, that is, with the suction port 11 facing the bottom surface of the sand collecting pit 2.

  Between the suction port 11 of the sand pump 10 and the bottom surface 2a of the sand collection pit 2, the disturbance nozzles 20a and 20b are disposed on the opposite sides of the suction port 11 to remove sand flowing into the sand collection pit from the central trough 1b described later. It is installed at a position that does not obstruct the flow (see FIG. 1B). Further, the disturbance nozzles 20 a and 20 b are arranged so that the injection directions thereof are substantially opposed with the suction port 11 of the sand pump 10 as the center. Accordingly, since the jetting directions give vectors opposite to each other at positions opposite to each other on the circle centered on the center of the suction port 11, sand precipitated near the suction port by jetting from the disturbance nozzles 20a and 20b is good. It is disturbed and efficiently sucked into the suction port.

As shown in FIG. 4, the pump well 30 connected to the sand basin 1 is provided with a drain pump 31 and a stagnant water pump 32 separately. The sewage such as rainwater pumped up by the staying water pump 32 ejects pressure water so that the sand accumulated on the bottom surface 1a of the sand basin 1 flows out toward the sand collecting pit 2 via a switching valve (not shown). It is supplied to the sand collecting nozzles 40, 41, 42 to be caused.
Although not shown, they are provided in the sand pump 10, the pump (not shown) for supplying pressure water to the disturbance nozzles 20a and 20b, and the supply pipes 21a and 21b for supplying pressure water to the disturbance nozzles 20a and 20b, respectively. The valves and the like are configured to be driven and controlled by a controller (not shown) formed around a programmable controller that controls the sand basin 1 in an integrated manner.

  Based on FIG. 3, the procedure of sand collection and sand lifting will be described in detail.

  First, the gate 50 is closed to stop the inflow of sewage into the sand basin 1 (step 1. Hereinafter, the step is referred to as “S”). Next, the staying water pump 32 drains the wastewater to a sewage settling basin, an inflow trough, etc. (not shown) through the switching valve (S2).

  Since the settling basin 1 is connected to the pump well 30 via the continuous portion 60, if it is described with reference to FIG. 4, it is drained by the staying water pump 32 to the level La which is the top level of the continuous portion 60. However, the accumulated water below the level La of the sand basin 1 is not drained. In other words, in the present invention, the stagnant water pump 32 drains the stagnant water in the pump well 30 and the sand basin 1 to the level La (S2 to S4).

  As described above, when the inflow of rainwater into the sand basin 1 is stopped (S1) and the process of draining the accumulated water in the sand basin 1 to the level La (S2 to S4) is completed, the supply pipes 21a and 21b are provided. The valves (not shown) are respectively opened to start the injection of pressure water from the disturbance nozzles 20a and 20b, and the counting of the first timer T1 (not shown) is started (S5). After the time-up of the first timer T1, the sand pump 10 is driven and the counting of the second timer T2 is started (S6, S7).

  When pressure water is ejected from the disturbing nozzles 20a, 20b, the jetting direction gives vectors opposite to each other at positions opposite to each other in a circle centered on the center of the suction port 11, so that the jetting force from the nozzles cancels out. Therefore, the sand accumulated in the vicinity of the suction port 11 is disturbed, and the disturbance gradually spreads over the entire sand collecting pit 2. Therefore, the sand is efficiently sucked from the suction port 11 by being accompanied by water and transferred to a predetermined place via the discharge pipe 12.

  After the time-up of the second timer T2, for example, the valves of the disturbance nozzles 20a and 20b are closed one minute after the start of the second timer T2 (S9). That is, the injection of the pressure water is stopped (Y in S11, S12). Even if the disturbance nozzles 20a and 20b are closed and the water ejected from the disturbance nozzles 20a and 20b disappears, the sand is turned into the water to be sucked because the vicinity of the suction port 11 is fluidized by driving the sand pump 10. Accompanied with effective discharge.

  Thus, the injection of the pressure water from the disturbance nozzles 20a and 20b only needs to destroy and disturb the accumulated sand in the vicinity of the suction port 11 of the sand pump 10, so that the disturbance time is the operation of the sand pump 10. A short time from before the start of is enough. Therefore, it is not necessary to always continue the injection of the pressure water from the disturbance nozzles 20a and 20b during the operation of the sand pump 10, so that the operation cost can be reduced.

  When the discharge of sand and water from the sand collection pit 2 by the sand collection pump 10 is completed, that is, when a water level meter (not shown) provided in the sand collection pit 2 detects a predetermined water level (Y in S10), The driving of the sand pump 10 is stopped (S11).

  Next, the valves of the sand collecting nozzles 40, 41, and 42 are sequentially opened to collect sand (S12). More specifically, a pressure fluid is jetted from the sand collecting nozzle 40 provided at the upper end of the central trough 1b in the extending direction of the central trough 1b to guide the sand sediment deposited on the central trough 1b into the sand collecting pit 2, The trough 1b is washed. The central trough 1b is the final and main trough connected to the sand collecting pit 2, and is therefore intended to prevent burial due to sedimentation when rainwater is received.

  And thereafter, the sand collecting nozzles 41, 41... Provided between the plurality of small troughs 1 c that communicate with the central trough 1 b and are provided on the bottom surface of the sand basin and orthogonal to the central trough 1 b, and the sand collecting nozzle 40. , 40 are alternately ejected. The sand collecting nozzles 41, 41... Eject the pressure fluid in a direction orthogonal to the extending direction of the central trough 1b. Sand collection to the sand collection pit 2 is performed through the small trough 1c and the central trough 1b by alternately ejecting the sand collection nozzles 41, 41.

  When the area of the bottom surface 1a of the sand basin is large, the bottom surface 1a is appropriately divided into a plurality of regions, and the plurality of sand collecting nozzles 41, 41. The ejection of pressure water from each sand collecting nozzle group is performed in order from the side closer to the sand collecting pit 2.

Finally, the sand accumulated in the pond width direction of the sand basin near the sand collection pit 2 is collected in the sand collection pit 2 by the sand collection nozzles 42 and 42 provided in the horizontal trough 2 b connected to the sand collection pit 2. When the water level meter in the sand collecting pit 2 detects a predetermined upper limit water level by sequentially opening the valves of the sand collecting nozzles 40, 41, 42, the driving of the sand pump 10 is resumed, and as the driving resumes, When the water level gauge detects a predetermined lower limit water level, the sand pump 10 is stopped. After the ejection from the sand collecting nozzles 42, 42, when the water level gauge detects a predetermined lower limit water level, the sand pump 10 is stopped driving and the state continues. Thereby, the sanding by the sand pump 10 is completed.
That is, the sand pump 10 resumes driving by detecting the upper limit water level of the water level gauge in accordance with the fluctuation of the water level in the sand collecting pit 2 from the start of driving to the stop of driving when the sanding is completed. Then, the driving is controlled to stop when the lower limit water level is detected.

  In the above-described example, a known submersible pump having a spiral blade is shown as the sand pump 10, but it is needless to say that it may be a jet pump. Moreover, although the number of nozzles in the sand collecting pit 2 is two, it may be three or more.

  In the above example, the disturbance nozzles 20a and 20b are provided with two timers T1 and T2 and driven before and after the sand pump 10 is driven. However, the timer is one and the sand pump 10 is driven. You may make it drive for the predetermined time before a start. However, as described above, when the disturbance nozzles 20a and 20b are driven before and after the sand pump 10 is driven, due to the synergistic effect of fluidization by the sand pump 10 and fluidization by the disturbance nozzles 20a and 20b. , Can further enhance the disturbing effect.

In the state where the accumulated water below the level La of the sedimentation basin 1 is not drained by the drainage by the accumulated water pump 32, the amount of pumped water by the sandpump increases, which is not economical, and the sand pressure is overcome by overcoming the water pressure. It is necessary to carry out sand collection by moving the sand and pressure water from the sand collection nozzles 40, 41, 42 is ejected at a high pressure, and high pressure sand collection is required. Not only does it cost to run, but the number of components increases, and when sand collection is performed at high pressure, part of the sand rises and floats in the water, and then sinks and accumulates again, reducing sand collection efficiency. As described above, there is a drawback, and the generation of sewage mist due to high-pressure water is also a serious problem in terms of hygiene.
Accordingly, in order to solve these problems, in the present invention, sand collection and pumping sand in a dry (drainage) state, and further sand collection (low pressure sand collection) for ejecting pressure water from the sand collection nozzle at low pressure are performed. I decided to do it.

As described above, after the pressure water is jetted from the disturbance nozzles 20a and 20b to the sand settled near the suction port 11 of the sand pump 10 of the present invention and disturbed for a certain time, the sand pump 10 is driven to level. Drain the stagnant water below La. At this time, it is preferable to use water pumped up by the staying water pump 32 for the disturbance nozzles 20a and 20b. And if it drains to the predetermined water level in the sand collection pit 2, the drive of the sand pump 10 will be stopped. Here, the predetermined water level is a water level that realizes a dry (drainage) state in the sand basin 1, and is set within a range where high load or high pressure sand collection of the sand pump 10 is not required. In the invention, the bottom level of the central trough 1b (between the upper end and the lower end of the bottom) is set to a predetermined water level.
As described above, when the drainage state is reached, sand collection, that is, pressure water ejection from the sand collection nozzle is performed, and the suspension of the sand pump 10 due to the water level of the settling basin having reached a predetermined water level and collection. When the water level of the sedimentation basin rises to the upper limit water level due to sand, the driving of the sand pump is resumed, and when the water level falls to the lower limit water level due to the resumption of driving, the driving of the sand pump 10 is stopped.

1 rainwater settling basin (sedimentation basin)
DESCRIPTION OF SYMBOLS 1a Bottom face of rainwater settling basin 1b Central trough 1c Small trough 1d Horizontal trough La Level of top of connected part 2 Sand collection pit 2a Sand collection pit bottom 10 Sand pump 11 Suction port 12 Discharge pipe 20a, 20b Disturbing nozzle 21a, 21b Supply pipe 40, 41, 42 Sand collecting nozzle

Claims (2)

In the sand-carrying method, sand collected on the bottom surface of the sand basin of the sewage treatment facility is collected in a sand collecting pit by jet water, and the sand is sucked and transferred by a sand-carrying device.
A sand pumping method, wherein pressure water is jetted from a sand collecting nozzle for flowing down sand deposited on a bottom surface of the sand basin when the water level of the sand basin is in a drainage state existing at a bottom level of a central trough.   2. The sand pumping method according to claim 1, wherein after the pressure water jet from the sand collecting nozzle is jetted on the central trough, jetting is performed on the bottom surface of the sand basin. The sanding method.

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