JP2004122041A - Sand collecting apparatus and sand collecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust to a proper value the pressure of the pressurized water to be supplied to a nozzle of a sand collecting apparatus for collecting the sand accumulated on the bottom surface of a sedimentation basin by jetting water from the nozzle. <P>SOLUTION: This sand collecting apparatus is provided with a water pressurizing pump 6, a sand collecting pit 2B and a jet pump 5 being a sand pumping pump arranged in the pit 2B. The water of a water source is sucked, pressurized and discharged by the pump 6, which is supplied to a plurality of the nozzles 3 through sand collecting pipelines 4 and jetted through jetting spouts of the nozzles 3. By the jetted pressurized water, the sand accumulated on the bottom surface 2A of the sedimentation basin 2 is collected in the pit 2B. A supply pressure adjusting means is arranged for adjusting the pressure of the pressurized water to be supplied to each of the nozzles 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sand collecting apparatus and a sand collecting method for collecting sedimentable substances such as sand deposited on a bottom of a sand basin provided in a water purification treatment facility or a sewage treatment facility, and particularly relates to a jet pump as a sand pump. The present invention relates to a sand collecting device and a sand collecting method for a sand basin to be used.
[0002]
Hereinafter, in this specification, the sedimentable substance such as sand deposited on the bottom of the sand basin is referred to as “sand”, and the sedimentary substance contained (before deposition) in wastewater described below is referred to as “sand”. "Underwater sand" is described, "collecting the settling sand in one place" is described as "sand collection", "collected settling sand is sucked up by a pump" is described as "lifting sand", and "direction of flowing wastewater". "Is described as a" longitudinal direction ", and a horizontal direction orthogonal to the" longitudinal direction "is described as a" width direction ". And in water purification and sewage treatment facilities, sand is mainly settled in a sand basin, and sedimentation and sedimentation of mud, organic turbidity, etc. are often performed in a settling basin downstream of the sand basin. , The above-mentioned “settling basin”.
[0003]
[Prior art]
When treating wastewater in a purified water treatment facility or a sewage treatment facility, wastewater containing a large amount of underwater sand is put into a sand basin, and the underwater sand is settled in the sand basin and removed as sediment. The method is generally adopted. Therefore, it is necessary to carry out the settling sand, and as one of the unloading facilities, a sand collecting pit is provided in a sand basin, and the sand collecting pit is collected in a sand collecting pit by a sand collecting device installed at the bottom of the sand basin. In addition, there is a facility for lifting the collected sand by a pump installed in a sand collection pit.
[0004]
There are the following two devices for collecting sand. The first device is a mechanical sand collecting device that collects sand using a mechanical scraper such as an underwater traction type, an underwater link belt type, or an underwater rotation type installed at the bottom of a sand basin. The second sand collecting device is an injection nozzle type sand collecting device in which a nozzle is provided instead of the mechanical scraper, and the sediment deposited on the bottom surface is pushed away by water jetted from the nozzle to collect sand. .
[0005]
Since the mechanical sand collecting device or the spray nozzle type sand collecting device is installed on the bottom surface and is always submerged, it is necessary to use a material having excellent corrosion resistance for components, but the mechanical sand collecting device is movable. Since there are many types of component parts with parts, even if a considerable part of the component parts is made of a material with excellent corrosion resistance, some of them will be materials that do not have excellent corrosion resistance, and failure due to corrosion is likely to occur, and rainwater or There is a problem that it is necessary to remove sewage and scrape out the settling sand, which requires time and effort for maintenance. On the other hand, the spray nozzle type sand collecting device is preferably used because it has no moving parts and the main components are only the nozzle and the pipe, so that it is easy to use a material having excellent corrosion resistance, and a failure due to corrosion hardly occurs. In addition, mechanical sand collectors are complicated and costly, and are susceptible to failure due to wear caused by mechanical operation. However, spray nozzle type sand collectors are inexpensive due to their simple structure. Since there is no dynamic operation, a failure hardly occurs, which is more preferable.
[0006]
A conventional apparatus for carrying out such sand is described with reference to FIG. 3 which is a schematic sectional view thereof. The bottom surface 2A of the sand basin 2 into which the wastewater 1 flows from left to right in the drawing has a concave sand collecting pit 2B at a substantially central portion in the longitudinal direction. A plurality of nozzles 3 are arranged on the bottom surface 2A with their injection ports facing the sand collecting pit 2B. The pressurized water from the sand collecting pump 706 is supplied to the nozzle 3 through the sand collecting water pipe 4 and injected from the injection port, and pushes down the settling sand (not shown) deposited and deposited on the bottom surface 2A to flow into the sand collecting pit 2B to collect. To sand. The sediment flowing into the sand collecting pit 2B is sucked up by the sand pump 705 and discharged out of the sand basin 2. When the sand basin 2 is long, it is preferable that the sand collecting pit 2B is located at an intermediate position in the longitudinal direction of the sand basin 2 because the sand can be collected from both sides in the longitudinal direction, and the sand collecting efficiency is improved.
[0007]
[Problems to be solved by the invention]
The force that pushes the sediment to the sand collecting pit in the injection nozzle type sand collecting device depends on the injection amount of the pressurized water injected from the injection port of the nozzle per unit time. When the injection amount is large, the velocity of the pressure water to be injected is large, and the force for flushing the settling sand is also large. The injection amount increases as the supply pressure of the pressure water to the nozzle increases, and decreases as the supply pressure decreases. Therefore, it is necessary to set the supply pressure to an appropriate value so that the sediment can be flushed to the sand collection pit. If the supply pressure is too low, the pushing force is too small and the sediment does not reach the sand collecting pit, and if it is too high, the pushing force is too large and the washed sand passes through the sand collecting pit and reaches the opposite side of the bottom, In either case, poor sand collection results.
[0008]
By the way, the water pressure applied to the settling basin is large when the depth of the wastewater of the settling basin is deep, but becomes small when the water depth is shallow, and becomes zero in the so-called dry state where there is no wastewater from the settling basin. In addition, the amount or hardness of the deposited sand may change due to fluctuations in the quality of the wastewater. The greater the pressure of the sedimentation and the greater the amount or hardness of the sedimented sediment, the worse the fluidity of the sedimentation. Generally, the supply pressure to the nozzle of the pressurized water is set to a value at which sedimentation of the sedimented sand with deteriorated flowability is possible, that is, a somewhat higher value. As described above, there was a problem that the sand collection was poor after passing through the pit. In addition, even if the supply pressure is set to an appropriate value at the time of design, the supply pressure may be too high as a result of the test operation, resulting in poor sand collection.
[0009]
FIG. 4 (the same parts are denoted by the same reference numerals as in FIG. 3) is a case where the sand basin 202 is short, and the position of the sand collecting pit 202B is provided at the longitudinal end of the sand basin 202. Even in this case, if the supply pressure is too high, the washed away sediment passes through the sand collection pit and reaches the opposite side of the bottom surface 202A. In FIG. 4, the opposite side of the bottom surface 202A is slightly raised so that the sedimentation does not easily pass through the sand collecting pit. However, due to the structure of the sand basin, the opposite side of the bottom surface 202A cannot be made too high. Failure cannot be sufficiently prevented.
[0010]
SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a sand collecting device and a sand collecting method for a sand basin, in which a value of a pressure supplied to a nozzle of a pressurized water to an appropriate value can be adjusted in order to prevent sand collecting failure. A sand device and a sand collecting method are provided.
[0011]
[Means for Solving the Problems]
Conventionally, the supply pressure of the pressure water to the nozzle was constant (high value as described above) regardless of whether the flowability of the sedimentation was good or bad. If the pressure was inappropriate, sand collection was poor. However, the present inventor has proposed a sand collecting device having a supply pressure adjusting means for supplying pressure water to the nozzle, or a collecting device capable of adjusting the supply pressure to the pressure water nozzle. Sand method.
[0012]
According to a first aspect of the present invention, sand deposited on the bottom of a sand basin having a pressure water pump, a sand collecting pit, and a sand pump disposed in the sand collecting pit is sucked from a water source to the pressure water pump. In a sand collecting device that is pressurized and discharged and supplied to a plurality of nozzles through a sand collecting water pipe and injected from an injection port of the nozzle, sand is collected in a sand collecting pit. A sand collecting apparatus characterized by having a supply pressure adjusting means.
[0013]
A second invention is the sand collecting apparatus according to the first invention, wherein the pressure adjusting means is an adjusting valve installed in the sand collecting pipe.
[0014]
A third invention is characterized in that a return pipe for returning the pressurized water to the water source is provided in the sand collecting pipe and / or the nozzle, and an adjustment valve serving as a pressure adjusting means is provided in the return pipe. 1 is a sand collecting device according to the first invention.
[0015]
A fourth invention is the sand collecting apparatus according to the first invention, wherein the pressure water pump is of a variable speed type, and the pressure adjusting means is the variable speed type pressure water pump.
[0016]
A fifth invention is the sand collecting device according to any one of the first to third inventions, wherein the sand pump is a jet pump driven by pressure water discharged from the pressure water pump.
[0017]
According to a sixth aspect of the present invention, sediment deposited on the bottom of a sand basin having a pressure water pump, a sand collecting pit, and a sand pump disposed in the sand collecting pit is sucked from a water source to the pressure water pump. In a sand collecting method in which sand is collected in a sand collecting pit by pressurized water discharged and supplied to a plurality of nozzles through a sand collecting water pipe and injected from an injection port of the nozzle, Sand collecting method, wherein the pressure of the pressurized water supplied to the nozzles is adjusted by changing the number of the nozzles to be sprayed and the nozzles not sprayed so as to spray the portion and not to spray the remainder. It is.
[0018]
A seventh invention is the sand collecting method according to the sixth invention, wherein the sand pump is a jet pump driven by pressurized water discharged from the pressure water pump.
[0019]
[Action]
According to the first aspect, the supply pressure to the nozzle can be adjusted to an appropriate value.
[0020]
In the second invention, if the regulating valve is fully opened, there is no pressure loss of the pressurized water at the place where the regulating valve of the sand collecting water pipe is present, and the supply pressure to the nozzle hardly decreases (that is, the initially set high pressure). By adjusting the opening of the regulating valve appropriately, reducing the effective cross-sectional area of the sand collection pipe at the location where the regulating valve is present, causing a pressure loss and reducing the supply pressure to the nozzle. Can be adjusted to an appropriate value.
[0021]
In the second invention, the nozzle is a so-called one-way type nozzle having no return path, but in the third invention, the nozzle is a so-called return type nozzle having a return path (or a return path is provided in a sand collecting water pipe. The return pipe serving as the return path is returned to the water tank, and an adjustment valve is installed in the return pipe. Contrary to the one-way system, in the case of the return system of the third invention, when the opening of the regulating valve is reduced, the pressure supplied to the nozzle of the pressure water increases, and when the opening is increased, the pressure of the nozzle increases. And the supply pressure to the nozzle can be adjusted to an appropriate value.
[0022]
In the fourth invention, the pressure of the pressure water discharged from the pressure water pump is reduced by lowering the rotation speed of the variable speed type pressure water pump, and the supply pressure to the nozzle is also reduced. Can be adjusted to an appropriate value.
[0023]
In the fifth invention, the pressure water for driving the jet pump is also used as the pressure water for supplying to the nozzle, so that it is not necessary to provide two pressure water pumps for driving the jet pump and supplying to the nozzle. 1. A single pressure water pump is sufficient, and the high pressure of the pressure water pump makes it possible to increase the pressure water injected from the nozzle to a high pressure, so that sand that is condensed and hard to flow can be easily collected. . If the sand collection and the sand lifting are performed at different times without overlapping, an increase in the load of the pressure water pump can be avoided, and a relatively small pressure water pump can be obtained.
[0024]
In the sixth invention, when the discharge pressure and the discharge amount of the pressure water pump are constant during sand collection, if the number of nozzles for injecting the pressure water (that is, the nozzle to which the pressure water is supplied) is small, the pressure water is reduced. The supply pressure of the pressurized water to the jetting nozzle increases, and as the number increases, the supply pressure decreases. Therefore, if some of the nozzles are not jetted, the supply pressure of the pressure water for jetting the pressurized water to the nozzles increases as described above, and if all the nozzles are jetted simultaneously, the supply pressure decreases.
[0025]
In the seventh invention, the pressure water for driving the jet pump is also used as the pressure water for supplying to the nozzle, so that it is not necessary to provide two pressure water pumps for driving the jet pump and supplying to the nozzle. 1. A single pressure water pump is sufficient, and the high pressure of the pressure water pump makes it possible to increase the pressure water injected from the nozzle to a high pressure, so that sand that is condensed and hard to flow can be easily collected. . If the sand collection and the sand lifting are performed at different times without overlapping, an increase in the load of the pressure water pump can be avoided, and a relatively small pressure water pump can be obtained.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings.
<First embodiment>
FIG. 1 is a side view schematically showing a sand lifting device for explaining Embodiment 1 of the present invention, and is a cross-sectional view of a sand basin, and FIG. 2 is a schematic view particularly showing a nozzle and a sand collecting pit. FIG. 2 is a plan view of FIG. 1 and illustrates a state in which a plurality of nozzles are divided into groups A to C. The same parts are denoted by the same reference numerals as in FIG. In FIG. 1, wastewater 1 flows in from the left to the right in the drawing of the sand basin 2 having the sand pump 5. The bottom surface 2A of the sand basin 2 has a concave sand collecting pit 2B at a substantially central portion in the longitudinal direction, and a suction port of a sand pump 5 serving as a jet pump is disposed in the sand collecting pit 2B. A plurality of nozzles 3 are arranged on the bottom surface 2A with their injection ports facing the sand collecting pit 2B. The underwater sand contained in the influent wastewater 1 precipitates and deposits on the bottom surface 2A to become sand. The illustration of the settling is omitted.
[0027]
Part of the wastewater 1 from which the underwater sand has been settled and which has flowed downstream of the sand basin is supplied to a water tank 7 through a water supply pipe 8 by a water supply pump (not shown), and becomes a water source (not shown). The water source is not limited to this, and any water can be used as long as large contaminants are removed so as not to clog the nozzle 3 and the jet pump.
[0028]
The water source in the water tank 7 is sucked by the pressure water pump 6, is pressurized and discharged, and becomes pressurized water. The drive valve 10 and the drive water pipe 12 are valves and pipes for supplying the pressure water as drive water for the jet pump. The drive valve 10 is open to supply pressure water, and the drive valve 10 is closed to supply pressure water. Will not be. The sand collecting valve 11 and the sand collecting pipe 4 are valves and pipes for supplying the pressure water to the nozzle 3 as sand collecting water. When the sand collecting valve 11 is opened and the pressure water is supplied, the sand collecting valve 11 is closed. Pressure water is no longer supplied. Since both the driving water and the sand collecting water use a large amount, the driving valve 10 and the sand collecting valve 11 are not opened at the same time, but one is opened and the other is closed. Not to be. By doing so, an increase in the load of the pressure water pump 6 can be avoided, and the pressure water pump 6 can be made relatively small, so that equipment costs and operation costs (electricity costs, etc.) can be reduced. it can.
[0029]
In this way, the pressure water for driving the jet pump discharged from the pressure water pump 6 is also used as the pressure water to be supplied to the nozzle 3, so that two pressure waters for driving the jet pump and supplying to the nozzle are provided. There is no need to provide a pump, and only one pressure water pump is required. In addition, since high-pressure water for driving the jet pump is supplied to the nozzle 3, it is possible to increase the pressure of the sand collected from the nozzle 3, so that the sand that is condensed and hard to flow can be easily collected. become. If the sand collection and the sand lifting are performed at different times without overlapping, an increase in the load of the pressure water pump can be avoided, and a relatively small pressure water pump can be obtained.
[0030]
At the time of sand collection, the pressure water pump 6 is operated, the drive valve 10 is closed, the sand collection valve 11 is opened, and the pressure water is supplied to the nozzle 3 through the sand collection water pipe 4 and injected from the injection port. Then, the sediment deposited on the bottom surface 2A is pushed away and flows into the sand collecting pit 2B to collect the sand.
[0031]
During sand lifting, the pressure water pump 6 is operated, the drive valve 10 is opened and the sand collection valve 11 is closed, and the pressure water drives the jet pump through the drive water pipe 12 to flow into the sand collection pit 2B. The settled sand is sucked up by the sand pump 5 and discharged out of the settling basin 2.
[0032]
The invention is not limited to the above, and a rotating blade type submersible sand pump may be used as the sand pump 5 and a dedicated pressure water pump may be provided as the sand collecting pump. In this case, the drive valve 10 and the sand collecting valve 11 become unnecessary, and the sand collecting and the sand collecting can be performed simultaneously.
[0033]
Conventionally, as described above, the supply pressure to the nozzle 3 is set to a value at which sedimentation of the settling sand whose flowability has deteriorated is set to a value that is somewhat high. The deposited sediment passes through the sand collection pit 2B, resulting in poor sand collection. In order to prevent this, an adjusting valve 9 is provided between the sand collecting valve 11 and the nozzle 3 of the sand collecting water pipe 4.
[0034]
The plurality of nozzles 3 on the upstream side of the sand collecting pit 2B (on the left side of the paper in FIGS. 1 and 2) are divided into groups A, B, and C in order of being closer to the sand collecting pit 2B as shown in FIG. The group can independently adjust the supply pressure to the nozzle 3 by the adjustment valve 9. The method of dividing the groups A to C is not limited to this, and is arbitrary. The finer the adjustment, the more it can be adjusted, and it is desirable. However, on the contrary, the equipment cost of the adjustment valve 9 and the like becomes expensive and the operation control becomes complicated. However, it is not preferable to make it too small. 1 and 2, the groups are divided in the longitudinal direction. However, the present invention is not limited to this. For example, in the case of a sand basin in which the amount of sedimentation is uneven in the width direction, the groups may be divided in the width direction. . In FIG. 2, the number of the plurality of nozzles 3 in the width direction is the same number in each of the groups A to C. However, the number is not limited to this, and the number in the width direction may be different for each group. The same applies to the plurality of nozzles 3 on the downstream side of the sand collecting pit 2B (on the right side of the paper in FIGS. 1 and 2).
[0035]
When the sedimentation has good fluidity, the opening of the regulating valve 9 is reduced to reduce the supply pressure to the nozzle 3, thereby preventing the pushed-out sedimentation from passing through the sand collection pit 2B and causing poor sand collection. If the flowability of the sand is poor, the opening is increased to increase the supply pressure so that the washed sand flows into the sand collecting pit 2B. By adjusting the supply pressure in this way, sand collection failure can be prevented.
[0036]
Among the groups A to C of the plurality of nozzles 3, the group A close to the sand collecting pit 2B needs the supply pressure adjustment, but the group C is not necessarily required. If the supply pressure to the nozzles C of the group C is set to a value at which the sand whose flowability has deteriorated can be washed away to a position where the nozzles 3 of the group B can collect the sand, The nozzles 3 of the B group and the A group are sequentially swept away and flow into the sand collecting pit 2B. As the flowability of the sedimentation improves, the sediment that has been washed away by the nozzles 3 of the group C reaches the group A through the group B and directly flows into the sand collection pit 2B. Absent. However, if the flowability of the sedimentation becomes extremely good, the sediment washed away by the nozzles C of the group C passes through the sand collecting pit 2B, so that the supply to the nozzles 3 of the group C is made so as not to be so (or extremely not). It is desirable to set the pressure. In addition, even when the settling sand passes through the sand collecting pit 2B, sand collecting failure does not substantially occur unless the degree is extreme. The setting of the supply pressure can be performed by the adjusting valve 9 of the group C, but is not limited to this. For example, the pipe diameter of the sand collection pipe 4 of the group C may be set so that the supply pressure is increased. Of the nozzle 3 may be designed to increase the supply pressure, and may be any method capable of increasing the supply pressure.
[0037]
The same applies to the group B, but when the flowability of the sedimentation becomes extremely good, it is easy for the sedimentation to pass through the sand collecting pit 2B, so the setting of the supply pressure to the nozzle 3 is more careful than in the case of the group C. Need to be done.
[0038]
The adjustment valve 9, the drive valve 10, and the sand collecting valve 11 are electric valves, and are controlled and driven by a control panel (not shown). In the case where the sand lifting device is small and simple, at least a part of each of the valves may be a manual valve, or the adjusting valve 9 is not provided, and the sand collecting valve 11 is provided with the function of the adjusting valve. You can also.
[0039]
Even when the sand collecting pit is provided at the end of the short sand basin described with reference to FIG. 4, the A to C groups on the upstream side of the sand collecting pit among the A to C groups of the plurality of nozzles 3. Is eliminated, and only the groups A to C on the downstream side of the sand collecting pit are provided. However, other than that, the case is the same as that of the long sand basin described with reference to FIGS.
[0040]
Although the above description is for the case of a so-called one-way type nozzle having no return path, the nozzle 3 may be a so-called return type nozzle having a return path. In this case, a return pipe (FIG. (Not shown) is returned to the water tank 7, and an adjusting valve is installed in the return pipe. Contrary to the one-way method, in the case of the return method, when the opening of the regulating valve is reduced, the supply pressure to the nozzle of the pressure water increases, and when the opening is increased, the supply pressure to the nozzle of the pressure water decreases. .
[0041]
<Embodiment 2>
At the time of sand collection, when the discharge pressure of the pressure water pump and the discharge amount are constant, if the number of nozzles for discharging the pressure water is small, the supply pressure to the nozzle of the pressure water for jetting the pressure water increases, and the number increases. If so, the supply pressure will decrease. In the first embodiment, at the time of sand collection, all the nozzles are jetted simultaneously. However, if some nozzles are not jetted, the supply pressure to the nozzle of the pressure water for jetting the pressure water becomes large as described above. Become. The second embodiment uses the above-described operation. In the same sand-lifting device as the first embodiment, the pressure is adjusted so that all the nozzles are simultaneously sprayed in a state where the flowability of the sedimentation is good and a good sand collecting state is obtained. Set the water supply pressure to the nozzle. If the fluidity of the settling sand deteriorates, some of the nozzles are not sprayed as described above.However, which nozzles are not sprayed, there are various combinations. Shown in
[0042]
(Combination example 1)
When the flowability of the settling sand deteriorates in the sand-lifting apparatus of FIGS. 1 and 2, at the time of sand collection, first, only the nozzle on the upstream side of the sand collection pit 2B is jetted to the nozzle of the pressure water on the upstream side. Is increased, and the sand on the upstream side flows into the sand collecting pit 2B. Next, the supply pressure of the downstream pressure water to the nozzle is increased by injecting only the nozzle on the downstream side of the sand collecting pit 2B, and the sediment on the downstream side flows into the sand collecting pit 2B.
[0043]
(Combination example 2)
In the first combination example, the upstream and downstream nozzles are alternately jetted in the sand lifting device of FIGS. 1 and 2. In the second combination example, the nozzles of the C to A groups are upstreamed for each group as follows. Side and downstream are injected simultaneously. When the flowability of the sedimentation becomes poor, at the time of sand collection, first, only the nozzles of the upstream side and the downstream side of the group C are jetted, and the supply pressure of the pressure water of the group C to the nozzles is increased. The sediment in the vicinity of the group is flushed to the vicinity of the group B, and only the nozzles of the group B on the upstream side and the downstream side, and only the nozzles of the group A on the upstream side and the downstream side are jetted, so that the sediment flows into the sand collecting pit 2B. Let it. If the degree of deterioration of the flowability of the sedimentation is not so remarkable, first, only the nozzles of the groups C and B are jetted, and then only the nozzles of the groups B and A are jetted to flow the sediment into the sand collecting pit 2B. You may make it do. Even when the sand collecting pit is provided at the end of the short sand basin described with reference to FIG. 4, the sand is collected by injecting the nozzles of the groups C to A for each group in the same manner as described above. Flow into sand pit.
[0044]
(Combination example 3)
If the degree of deterioration in the fluidity of the sedimentation is extremely significant, the supply pressure of the pressurized water to the nozzle can be considerably increased by multiplying the combination examples 1 and 2 as follows. In the sand collecting apparatus shown in FIGS. 1 and 2, when collecting sand, first, the nozzles of the upstream groups C to A are sequentially jetted for each group, and then the nozzles of the downstream groups C to A are sequentially jetted for each group. Then, the settled sand flows into the sand collection pit 2B. If the degree of deterioration of the flowability of the sedimentation is not so remarkable, first, only the nozzles of the upstream groups C and B are injected, and then only the nozzles of the upstream groups B and A are injected. Only the nozzles of the downstream groups C and B may be jetted, and then only the nozzles of the downstream groups B and A may be jetted to cause the sediment to flow into the sand collection pit 2B.
[0045]
In each of the above combinations, some of the nozzles are not ejected. For example, when the nozzles of the group C are not ejected, the adjustment valve 9 for the group C may be completely closed. Good. Note that a dedicated on-off valve (not shown) may be provided for each group without fully closing the adjustment valve 9.
[0046]
<Embodiment 3>
If the discharge pressure and discharge amount of the pressure water pump can be changed during sand collection, the supply pressure of the pressure water to the nozzle can also be changed. In the third embodiment, the above is used. In the same sand-lifting device as the first embodiment, the adjusting valve 9 is eliminated, and the pressure water pump is a variable speed pump such as an inverter motor type. By reducing the rotation speed of the variable-speed type pressure water pump, the pressure of the pressure water discharged from the pressure water pump decreases, and therefore the supply pressure to the nozzle also decreases. Can be adjusted. In the first embodiment, the opening degree of the regulating valve 9 is adjusted to adjust the supply pressure to the nozzle 3. In the fourth embodiment, the rotation speed of the pressure water pump is adjusted to adjust the supply pressure to the nozzle 3. The rest is the same as in the first embodiment.
[0047]
In the present invention, the combinations of the first to third embodiments can be arbitrarily performed.
[0048]
As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and can be various forms, and can be any sand collecting method that meets the gist of the present invention. The shape of the sedimentation basin, the number or arrangement of the nozzles, the operation or control method of each valve or pump, and the like can be any one satisfying the function. Of course, various improvements and changes can be made without departing from the spirit of the present invention.
[0049]
【The invention's effect】
{Circle over (1)} According to the present invention, in the sand collecting device and the sand collecting method of the sand basin, the sand pressure failure can be prevented by adjusting the value of the pressure supplied to the nozzle of the pressurized water to an appropriate value. A sand collecting device and a sand collecting method can be provided.
{Circle over (2)} According to the present invention, the pressure water for driving the jet pump discharged from the pressure water pump 6 is also used as the pressure water to be supplied to the nozzle 3, so that the pressure water for driving the jet pump and the supply to the nozzle are provided. It is not necessary to provide two pressure water pumps, and only one pressure water pump is required.
{Circle around (3)} In the present invention, if the sand collection and the sand lifting are performed at different times without overlapping, an increase in the load of the pressure water pump can be avoided, and a relatively small pressure water pump can be obtained.
(4) According to the present invention, when the flowability of the sedimentation is good, the opening degree of the regulating valve 9 is reduced to reduce the supply pressure to the nozzle 3, so that the washed-out sediment passes through the sand collection pit 2B. Prevents poor sand collection, and when the flowability of the sedimentation is poor, increases the opening to increase the supply pressure so that the flushed sand flows into the sand collection pit 2B satisfactorily. . By adjusting the supply pressure in this way, sand collection failure can be prevented.
[Brief description of the drawings]
FIG. 1 is a side view schematically showing a sand lifting device for describing Embodiment 1 of the present invention.
FIG. 2 is a plan view of FIG. 1, particularly schematically showing a nozzle and a sand collecting pit.
FIG. 3 is a schematic cross-sectional view of a sand lifting device showing a conventional method for carrying out settling sand.
FIG. 4 is a schematic sectional view of the sand lifting device showing a case where a sand basin is short in FIG.
[Explanation of symbols]
1 wastewater
2 sand basin
2A bottom
2B Sand collection pit
3 nozzles
4 Sand collection pipe
5 jet pump
6 pressure water pump
7 Aquarium
8 Water pipe
9 Adjusting valve
10 Drive valve
11 Sand collecting valve
12 Drive water piping

Claims (7)

A pressure water pump, a sand collection pit, and sand deposited on the bottom of a sand basin having a sand pump disposed in the sand collection pit,
Sand collected by the pressure water pump is sucked from the water source, is discharged under pressure, is supplied to a plurality of nozzles through a sand collecting pipe, and is collected in the sand collecting pit by the pressure water injected from the injection port of the nozzle. In the device,
A sand collecting device comprising a supply pressure adjusting means for supplying the pressure water to the nozzle. The sand collecting device according to claim 1, wherein the pressure adjusting means is an adjusting valve installed in the middle of the sand collecting pipe. 2. A return pipe for returning the pressurized water to the water source is provided in the sand collecting water pipe and / or the nozzle, and an adjustment valve serving as a pressure adjusting means is provided in the middle of the return pipe. 3. Sand collecting equipment. 2. The sand collecting device according to claim 1, wherein the pressure water pump is of a variable speed type, and the pressure adjusting unit is the variable speed type pressure water pump. 3. The sand collecting device according to claim 1, wherein the sand pump is a jet pump driven by pressure water discharged from the pressure water pump. A pressure water pump, a sand collection pit, and sand deposited on the bottom of a sand basin having a sand pump disposed in the sand collection pit,
Sand collected by the pressure water pump is sucked from the water source, is discharged under pressure, is supplied to a plurality of nozzles through a sand collecting pipe, and is collected in the sand collecting pit by the pressure water injected from the injection port of the nozzle. In the method,
Adjusting the supply pressure of the pressure water to the nozzle by injecting a part of the plurality of nozzles, not injecting the rest, and changing the number of nozzles to be ejected and those not to be ejected. Characterized sand collection method. The sand collecting method according to claim 6, wherein the sand pump is a jet pump driven by pressure water discharged from the pressure water pump.

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