Low solid content sewage cyclone desanding system and control method thereof

Abstract

The present application belongs to the field of sewage treatment, and discloses a low solid content sewage cyclone desanding system and a control method thereof, which comprises a pressure transmitter arranged in an inlet pipe, a plurality of cyclones connected with the inlet pipe, a plurality of first valves arranged in inlet pipe lines of the cyclones and associated with the pressure transmitter, a first sand outlet of the cyclone arranged with a sand collecting chamber, a second valve arranged at an outlet end of the sand collecting chamber, a sand-water separator connected with the outlet end of the second valve, a controller connected with the pressure transmitter, the first valves, the cyclones, the second valve and the sand-water separator, and the number of the cyclones, the first valves, the sand collecting chambers and the second valves is equal and they are arranged on parallel branches in correspondence, and each parallel branch comprises three or more than three. The system can automatically regulate and control the operation of the cyclone according to the total inlet water pressure fluctuation, solve the problems of unstable flow state and poor desanding effect caused by the inlet water flow fluctuation, and is suitable for the desanding treatment of low solid content sewage with large inlet water fluctuation. The system is efficient, stable and has good desanding effect.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment equipment, specifically relating to a low solids content wastewater cyclone sand removal system and its control method. Background Technology

[0002] Sand removal in wastewater pretreatment is an indispensable part of wastewater treatment plants. The effectiveness of sand removal directly affects the treatment efficiency and operation and maintenance workload of subsequent treatment units. Traditional sand removal systems mainly include horizontal flow grit chambers, aerated grit chambers, or cyclone grit chambers, all of which are primarily civil engineering structures. All three require pumping or air lifting, leading to problems such as sand clogging and wear. Furthermore, all three are almost ineffective at removing fine sand smaller than 200μm. To address this, the applicant previously developed a high-precision cyclone sand removal system (such as the wastewater sand removal system disclosed in patent CN215288245U), which can effectively remove fine sand smaller than 200μm. However, during use, problems such as easy clogging and unstable sand removal performance were found.

[0003] Furthermore, during wastewater treatment plant operation, the liquid level control target of the booster pump pool is mainly achieved by controlling the number or frequency of operating booster pumps. However, the influent flow rate fluctuates significantly between the rainy and dry seasons, and between the flood season and the non-flood season, with the treatment volume variation coefficient reaching over 1.5. Under these circumstances, the large fluctuations in influent flow rate will have a significant impact on the operation of the hydrocyclones. Existing processes often employ two hydrocyclones, one in operation and one on standby. The hydrocyclone inlet is switched manually using a manual gate. However, these manual gates have a large diameter, resulting in high labor intensity, slow switching, and an inability to respond promptly to instantaneous fluctuations in water volume. This can cause instability in the hydrocyclone's operating conditions and internal flow field, and even lead to operating parameters deviating from the normal operating range, resulting in unstable sand removal efficiency. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides a low-solids-content wastewater cyclone sand removal system and its control method. This system can automatically adjust and control the operation of the cyclone according to the fluctuation of the total influent pressure, solving problems such as unstable operating flow and poor sand removal effect caused by fluctuation of influent flow. It is suitable for sand removal treatment of wastewater with large fluctuation of influent flow and low solids content. The system operates efficiently and stably with good sand removal effect.

[0005] The technical solution adopted in this invention is as follows:

[0006] A low-solids-content wastewater cyclone sand removal system includes:

[0007] Pressure transmitter, installed on the water inlet pipe;

[0008] Multiple hydrocyclones are connected in parallel, and the upper inlet pipe of each hydrocyclone is connected to the water supply pipe via a pressure equalizing flow distributor.

[0009] Multiple first valves are respectively installed on the inlet pipe of each of the hydrocyclones, and each first valve is associated with the pressure transmitter;

[0010] Each hydrocyclone has a sand collection chamber connected to the first sand discharge port at the bottom of its cyclone.

[0011] Multiple second valves are provided, with each of the sand collection chambers having a second valve at its outlet end;

[0012] A sand-water separator, connected to the outlet end of each of the second valves, is used for sand-water separation of concentrated sand;

[0013] The controller is electrically connected to the pressure transmitter, the first valve, the hydrocyclone, the second valve, and the sand-water separator;

[0014] The number of cyclones, the first valve, the sand collection chamber and the second valve are equal and correspond one-to-one on the parallel branches, and the parallel branches include three or more.

[0015] In one embodiment of this application, all the second valves are interconnected, and each second valve is associated with a first valve on the same parallel branch;

[0016] And / or, all of the cyclones are associated with the pressure transmitter;

[0017] And / or, each of the cyclones is associated with the first valve on the corresponding inlet line.

[0018] In one embodiment of this application, all the sand collection chambers are provided with backflush air branches, and the backflush air branches are provided with one-way air inlet valves and air inlet switch valves. The one-way air inlet valves are located at the end of the backflush air branches and are located inside the sand collection chambers; all the backflush air branches are connected to an air compressor.

[0019] A pressure monitor is installed on the pipeline between the first sand discharge port and the sand collection chamber inlet, and the pressure monitor is associated with the air inlet switch valve.

[0020] In one embodiment of this application, the one-way intake valve includes:

[0021] The valve body is a cylindrical structure with one blind end and the other end open and connected to the backflush gas branch.

[0022] The valve core is adapted to the interior of the valve body and is axially and slidably disposed within the valve body.

[0023] An elastic element is disposed within the valve body, located between the blind end of the valve body and the valve core;

[0024] The valve body has several vent holes distributed circumferentially on its side wall. When the elastic element is reset, it pushes the valve core to block the vent holes. When the backflushing gas branch introduces pressurized gas into the sand collection chamber, the pressurized gas pushes the valve core to compress the elastic element and open the vent holes.

[0025] In one embodiment of this application, the valve body further includes one or more of the following:

[0026] The valve body has a limiting part inside the opening end to limit the valve core. When the valve core abuts against the limiting part, the exhaust hole is blocked.

[0027] The valve body has a drain hole on the side wall near the blind end;

[0028] The valve body opening has an external thread at one end, which is connected to the sand collection chamber and / or the backflushing air branch via a threaded joint.

[0029] In one embodiment of this application, the sand-water separator includes a settling hopper and a conveying mechanism; the settling hopper is provided with an overflow port, a drain port and an empty port from top to bottom; the conveying mechanism is a spiral conveying mechanism, one end of which is connected to the bottom of the settling hopper and the other end is provided with a second sand discharge port; the hydrocyclone and the sand collection chamber are directly connected above the settling hopper via a riser pipe.

[0030] In one embodiment of this application, the first valve is a pneumatic gate valve;

[0031] And / or, the second valve is a pneumatic clamp valve;

[0032] And / or, the pressure equalizing flow distributor includes a main inlet pipe and at least three outlet branch pipes, wherein the flow area of ​​the main inlet pipe is greater than or equal to the sum of the flow areas of the outlet branch pipes.

[0033] A control method for a low-solids-content wastewater cyclone sand removal system, employing any one of the above-described low-solids-content wastewater cyclone sand removal systems, includes the following steps:

[0034] S100: Obtain the total inlet water pressure WP1 of the water pipe, and control the number of opening / closing of the first valve and the opening / closing of the corresponding hydrocyclone according to the total inlet water pressure WP1;

[0035] S200, record the cumulative opening time t1 of each first valve. When the cumulative opening time t1 of any first valve is greater than or equal to the preset time T0, the second valve on the parallel branch where the first valve is located meets the opening and sand discharge conditions. When the cumulative opening time t1 of any first valve is less than the preset time T0, the second valve on the parallel branch where the first valve is located does not meet the opening and sand discharge conditions.

[0036] S300, the sand-water separator operates according to an operating cycle, each operating cycle including multiple process steps, and the second valve is opened to discharge sand only during the water inlet stage of each operating cycle.

[0037] In one embodiment of this application, in step S100:

[0038] When the total inlet water pressure WP1 is within the normal operating pressure range P 下限值 ~P 上限值 Within this timeframe, open N of the first valves and their corresponding cyclones, where N ≥ 2;

[0039] When the total inlet water pressure WP1 is less than P 下限值 When, turn on N - For each of the first valves and their corresponding cyclones, 1 ≤ N - <N;

[0040] When the total inlet water pressure WP1 is greater than P 上限值 When, turn on N + The first valve and its corresponding cyclone separator, N + >N and N + ≥3.

[0041] In one embodiment of this application, in step S200:

[0042] All the second valves are set to a cyclical, rotating start sequence. When the rotation reaches the start sequence of any second valve and that second valve meets the conditions for opening and discharging sand, the second valve opens to discharge sand from the bottom flow. The sand discharge continues for a predetermined sand discharge time T. 排 The second valve will then automatically close. When the startup sequence of any second valve is reached, if the second valve does not meet the conditions for opening and discharging sand, the second valve will not open, and the startup sequence will proceed to the next second valve.

[0043] When any of the first valves is opened, the opening time of the first valve is recorded. When the first valve is closed, the timer stops and the record is not cleared. When the first valve is opened again, the timer continues to be recorded until the cumulative opening time t1 is greater than or equal to the preset time T0. Then the corresponding second valve meets the opening and sand discharge conditions. After the second valve that meets the opening and sand discharge conditions is turned into the start-up sequence and opens to discharge sand, the cumulative opening time t1 of the corresponding first valve is cleared and the next round of timing begins.

[0044] When the second valve is opened to discharge sand from the bottom flow, the corresponding first valve is closed.

[0045] In one embodiment of this application, in step S300: the multiple process steps of the operating cycle include an initialization step, a water inlet step, a sedimentation step, a drainage step, and a sand separation step set in sequence; the second valve is opened to discharge sand only in the water inlet step of each operating cycle, and then the sand-water separator performs subsequent processing. The next operating cycle can only begin after one operating cycle is completed; if the previous operating cycle has not ended, but the next second valve has met the conditions for opening and discharging sand, the next second valve is delayed and waits.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0047] 1. The low solids content wastewater cyclone sand removal system of the present invention is equipped with a pressure transmitter to detect the total inlet water pressure and is associated with the first valve on the parallel branch of the cyclone separator. The opening and closing operation of the cyclone separator branch is automatically controlled according to the change of the total inlet water pressure, which can effectively solve the problems of unstable operating flow and poor sand removal effect caused by fluctuation of inlet water volume. A sand collection chamber and a second valve are set at the bottom of the cyclone separator, which can perform intermittent sand discharge, adapting to the sand removal treatment of low solids content wastewater, effectively increasing the sand discharge concentration and reducing the hydraulic load of the sand-water separator. The low solids content wastewater cyclone sand removal system is highly efficient and stable in operation, and has a good sand removal effect.

[0048] 2. By associating the first valve and the second valve on the same parallel branch, the automatic opening of the second valve is controlled based on the cumulative opening time of the first valve, thereby achieving automatic control of intermittent underflow sand discharge. Both the first and second valves are pneumatic valves, and the second valve is a pneumatic clamp valve, which can achieve automatic and rapid opening and closing, avoiding problems such as sealing failure caused by sand particles blocking and wear. It can achieve precise dynamic flow regulation and precise underflow sand discharge control, which can effectively improve the stability and reliability of system operation.

[0049] 3. A backwash air branch is set up to connect with the sand collection chamber, which can backwash the sand collection chamber and the first sand discharge port. This can effectively solve problems such as fine sand caking in the sand collection chamber and blockage of the first sand discharge port at the bottom of the hydrocyclone, ensuring smooth intermittent sand discharge and stable system operation.

[0050] 4. The hydrocyclone and sand collection chamber are installed above the sand settling hopper via a riser, so that the hydrocyclone, sand collection chamber and sand settling hopper are directly connected along the direction of gravity. This improves the structural layout of the equipment, avoids the setting of horizontal pipe sections, and thus avoids the problem of sand accumulation and blockage in horizontal pipe sections. At the same time, it can save more than 20% of the floor space.

[0051] 5. The control method of this application realizes automatic and coordinated control of three parts: hydrocyclone inlet, intermittent sand discharge from the hydrocyclone underflow, and sand-water separator. This enables the low solids content sewage hydrocyclone sand removal system of this application to achieve fully automated and intelligent control, effectively cope with instantaneous water volume fluctuations, ensure smooth internal flow and stable operating conditions of the hydrocyclone, guarantee the sand removal effect, and at the same time ensure the system's rapid response, precise control, high efficiency, and stable operation. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of a low-solids-content wastewater cyclone sand removal system according to this application.

[0054] Figure 2 This is a front view schematic diagram of the installation structure of a low solids content wastewater cyclone sand removal system according to this application.

[0055] Figure 3 This is a side view schematic diagram of the installation structure of a low solids content wastewater cyclone sand removal system according to this application.

[0056] Figure 4 A schematic diagram of a backflushing air branch for the sand collection chamber.

[0057] Figure 5 This is a schematic diagram of the one-way air intake valve in its state when backflushing is not performed.

[0058] Figure 6 This is a schematic diagram of the one-way air intake valve during backwashing.

[0059] Figure 7 for Figure 6 A cross-sectional view along the AA direction.

[0060] Figure 8 This is a schematic diagram of one implementation of a pressure equalization flow distributor.

[0061] Figure 9 This is a schematic diagram of another implementation of the pressure equalization flow distributor.

[0062] Figure 10 This is a schematic diagram of the control method for the low solids content wastewater cyclone sand removal system in this application.

[0063] Figure label:

[0064] 1. Pressure transmitter;

[0065] 2. Pressure equalizing flow distributor; 21. Main inlet pipe; 22. Branch outlet pipe;

[0066] 3. First valve;

[0067] 4. Hydrocyclone; 41. First sand discharge port;

[0068] 5. Sand collection chamber;

[0069] 6. Second valve;

[0070] 7. Sand-water separator; 71. Sand settling hopper; 711. Overflow port; 712. Drainage port; 713. Air vent; 72. Conveying mechanism; 721. Second sand discharge port.

[0071] 8. Backflush air branch; 81. One-way air intake valve; 811. Valve body; 8111. Exhaust port; 8112. Limiting part; 8113. Drain hole; 812. Valve core; 813. Elastic element; 82. Backflush switch valve. Detailed Implementation

[0072] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0073] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "length," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0074] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0075] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0076] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0077] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention.

[0078] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0079] like Figures 1 to 3 As shown in the figure, this embodiment of the invention provides a low-solids-content wastewater cyclone sand removal system. The system includes: a pressure transmitter 1, multiple hydrocyclones 4, multiple first valves 3, multiple sand collection chambers 5, multiple second valves 6, a sand-water separator 7, and a controller (not shown in the figure). The multiple hydrocyclones 4 are connected in parallel to form multiple parallel branches, and each parallel branch is sequentially equipped with a first valve 3, a hydrocyclone 4, a sand collection chamber 5, and a second valve 6.

[0080] Specifically, pressure transmitter 1 is installed on the water inlet pipe to detect the total inlet water pressure. It can convert the pressure into an electrical signal to determine the inlet water flow rate.

[0081] Multiple hydrocyclones 4 are connected in parallel after the pressure transmitter 1, that is, multiple parallel branches are provided after the pressure transmitter 1, and one hydrocyclone 4 is provided on each parallel branch. The inlet pipes of the multiple hydrocyclones 4 are connected to the water supply pipe through the pressure equalization flow distributor 2, so that the water flow is evenly distributed into the opened hydrocyclones 4, and the inlet water pressure of the hydrocyclones 4 operating at the same time is kept consistent.

[0082] Multiple first valves 3 are respectively installed on the inlet pipe of each hydrocyclone 4. That is, each hydrocyclone 4 has a corresponding first valve 3 on its inlet pipe. The opening and closing of the first valves 3 controls whether the water flow enters the corresponding hydrocyclone 4. Each first valve 3 is associated with a pressure transmitter 1 and is linked for control. The transmitter 1 can control the opening or closing of each first valve 3 based on the change in total inlet water pressure (i.e., the change in flow rate) detected by the pressure transmitter 1. This controls the number of hydrocyclones 4 in operation, realizes automatic and rapid adjustment and equalization of the water flow entering the hydrocyclone 4, avoids the impact of inlet flow fluctuations on the hydrocyclone 4 and affects the sand removal effect, and ensures the efficient and stable operation of the hydrocyclone sand removal system.

[0083] Multiple sand collection chambers 5 are respectively located at the first sand discharge port 41 at the bottom of each hydrocyclone 4, that is, each first sand discharge port 41 at the bottom of each hydrocyclone 4 is connected to a sand collection chamber 5. The sand collection chamber 5 is used to collect and temporarily store the solid particles settled by the hydrocyclone 4.

[0084] Multiple second valves 6 are respectively installed on the outlet end pipeline of each sand collection chamber 5, that is, each sand collection chamber 5 is provided with a second valve 6, and the discharge of sand and water in the sand collection chamber 5 is controlled by opening and closing the second valve 6.

[0085] The sand-water separator 7 is connected to the outlet end of each second valve 6, that is, the sand-water separator 7 is connected to the outlet end of each sand collection chamber 5. It is used to treat the concentrated sand collected in the sand collection chamber 5 by sedimentation, drainage, and sand separation, so as to achieve complete separation of sand and water, thereby realizing the sand removal treatment of wastewater. Preferably, one set of sand-water separator 7 is included, which can treat the concentrated sand water discharged from each sand collection chamber 5 separately, saving equipment investment; of course, multiple sets of sand-water separator 7 can also be set.

[0086] A sand collection chamber 5 and a second valve 6 are installed at the bottom of the hydrocyclone 4 to achieve intermittent sand discharge, which is suitable for sand removal treatment of wastewater with low solids content. It can effectively increase the sand discharge concentration and reduce the hydraulic load of the sand-water separator 7. This low solids content wastewater hydrocyclone sand removal system is highly efficient and stable in operation, and has a good sand removal effect.

[0087] The controller (not shown in the figure) is electrically connected to the pressure transmitter 1, the first valve 3, the hydrocyclone 4, the second valve 6, and the sand-water separator 7, etc., and realizes the automated and intelligent control of the system through the controller. The controller is preferably a PLC controller.

[0088] Among them, the number of hydrocyclones 4, first valves 3, sand collection chambers 5, and second valves 6 is equal, and they are arranged in one-to-one correspondence on parallel branches. The parallel branches of this system include 3 or more than 3, that is, it includes at least 3 hydrocyclones 4 and parallel branches. Setting at least 3 parallel branches can be well adjusted according to the fluctuation of the influent flow rate, adapt to the decrease and increase of the water volume fluctuation, and have a wider adaptation range and stronger adaptability.

[0089] Preferably, all the second valves 6 on the parallel branches are interconnected, and each second valve 6 is associated with the first valve 3 on the same parallel branch.

[0090] For example, when there is one set of sand-water separator 7, and the sand-water separator 7 only processes the concentrated sand deposited in a fixed number (such as one or two) of sand collection chambers 5 at a time, then only less than or equal to this fixed number of second valves 6 can be opened to discharge concentrated sand to the sand-water separator 7 at a time; all the second valves 6 are interconnected to achieve associated control, which can effectively prevent more second valves 6 from opening simultaneously, causing the problem of overloading operation of the sand-water separator 7.

[0091] The second valve 6 is associated with the first valve 3, and the second valve 6 can be controlled to open automatically by accumulating the opening duration of the first valve 3. That is, when the first valve 3 is opened and the hydrocyclone 4 operates, the opening duration of the first valve 3 is calculated. When the accumulated opening duration reaches the set duration, the second valve 6 can be controlled to open automatically for intermittent discharge of concentrated sand. It realizes automatic control and avoids the premature or late opening of the second valve 6, which affects the sand removal efficiency and effect of the hydrocyclone 4, as well as the periodic operation of the sand-water separator 7.

[0092] Preferably, the first valve 3 is a pneumatic gate valve; the second valve 6 is a pneumatic pipe clamp valve. Using pneumatic valves can achieve automatic and rapid closing of the valves, realizing automatic control while achieving rapid and precise control, with low cost and strong practicability. The second valve 6 at the bottom of the sand collection chamber 5 uses a pneumatic pipe clamp valve to replace the conventional electric valve. Through the pneumatic actuator, the sand discharge opening and closing control time can be less than 5s. At the same time, the structure of the pipe clamp valve can effectively avoid the sealing failure caused by sand particle jamming and wear. Among them, the first valve 3 is controlled in a power-off normally open mode, and the second valve 6 is controlled in a power-off normally closed mode, with low operating energy consumption.

[0093] In one embodiment, all the hydrocyclones 4 are associated with the pressure transmitter 1 to achieve linkage, and the number of operating hydrocyclones 4 is controlled according to the change of the total influent pressure detected by the pressure transmitter 1. And / or, each hydrocyclone 4 is associated with the first valve 3 on the corresponding branch to achieve linkage. When the first valve 3 on its inlet pipe is opened, the hydrocyclone 4 also starts to operate at the same time. When the first valve 3 on its inlet pipe is closed, the hydrocyclone 4 also closes, realizing synchronous automatic control.

[0094] Preferably, each sand collection chamber 5 is equipped with a backflushing air branch 8, and each backflushing air branch 8 is equipped with a one-way inlet valve 81 and a flushing switch valve 82. The one-way inlet valve 81 is located at the end of the backflushing air branch 8, within the sand collection chamber 5; the flushing switch valve 82 is preferably a ball valve. All backflushing air branches 8 are connected to an air compressor or a high-pressure air source (not shown in the figure), and can share a single air compressor or high-pressure air source to provide pressurized gas. Alternatively, multiple air compressors or multiple high-pressure air sources can be installed. The flushing switch valve 82 controls the opening and closing of the backflushing air branch, and the one-way inlet valve 81 prevents sewage, fine sand, etc., from flowing back and clogging the air pipes in the sand collection chamber 5.

[0095] Furthermore, a pressure monitor (not shown in the figure) is installed on the pipeline between the first sand discharge port 41 at the bottom of the hydrocyclone 4 and the inlet at the top of the sand collection chamber 5. This pressure monitor is connected to the controller and associated with the corresponding air-purging switch valve 82 on the same parallel branch. When the first sand discharge port 41 is opened and the pressure monitor detects insufficient pipeline pressure, it indicates that the sand discharge channel and / or the first sand discharge port 41 is blocked. At this time, the air-purging switch valve 82 can be opened to start the automatic air-purging mode.

[0096] Setting up a backflushing air branch 8 can flush air into the sand collection chamber 5 and the first sand outlet 41 at the bottom of the cyclone separator 4. This can effectively solve the problems of internal sand compaction, caking, and "arching" caused by long accumulation time and the effects of operating pressure and gravity, which in turn cause blockage in the sand collection chamber 5 and the first sand outlet 41.

[0097] like Figures 4 to 7 As shown, in one embodiment, the one-way intake valve 81 includes a valve body 811, a valve core 812, and an elastic element 813. The valve body 811 has a cylindrical structure, with one end being a blind end and the other end open and communicating with the backflush branch 8. The valve core 812 is adapted to the internal cavity of the valve body 811 and is axially sealed and slidably disposed within the valve body 811. The elastic element 813 is disposed within the valve body 811, located between the blind end of the valve body 811 and the valve core 812. The elastic element 813 is preferably a compression spring, but it can also be other elastic components with compression and reset functions. The valve body 811 has several vent holes 8111 distributed circumferentially on its side wall, corresponding to the position of the valve core 812 when it is reset. When the elastic element 813 is reset, it pushes the valve core 812 to block the vent holes 8111. When the backflushing air branch 8 is vented and pressurized gas is introduced into the sand collection chamber 5, the pressurized gas can push the valve core 812 to compress the elastic element 813, moving it towards the blind end of the valve body 811, thus opening the vent holes 8111. This achieves unidirectional air intake, and the vent holes 8111 are closed when there is no backflushing.

[0098] Furthermore, the valve body 811 has a limiting part 8112 inside the opening end to limit the valve core 812. When the elastic member 813 extends and resets to push the valve core 812 to abut against the limiting part 8112, the valve core 812 blocks the exhaust hole 8111. The limiting part 8112 can position and limit the valve core 812 to ensure accurate and stable one-way sealing.

[0099] The valve body 811 has a drain hole 8113 on the side wall near the blind end. The drain hole 8113 is provided to prevent dirt from accumulating and clogging inside the valve body 811, while ensuring smooth sealing and sliding of the valve core 812.

[0100] In one embodiment, the valve body 811 has an external thread at one open end, and the valve body 811 is threadedly connected to the side wall of the sand collection chamber 5 via a threaded joint; alternatively, the valve body 811 is threadedly connected to the pipeline of the backflushing air branch 8 via a threaded joint; or, the valve body 811 is threadedly connected to both the side wall of the sand collection chamber 5 and the pipeline of the backflushing air branch 8 via a threaded joint. The valve body 811 is installed via a threaded connection, making installation, disassembly, and maintenance convenient.

[0101] like Figures 1 to 3 As shown, the sand-water separator 7 includes a settling hopper 71 and a conveying mechanism 72. The settling hopper 71 has, from top to bottom, an overflow port 711, a drain port 712, and an empty port 713. The overflow port 711 is level with or higher than the concentrated sand discharge inlet. The drain port 712 is located in the middle of the settling hopper 71 and is used to discharge the upper layer of clear water after the concentrated sand has settled. The empty port 713 is located at the bottom of the settling hopper 71 and is used for emptying. All three ports—overflow port 711, drain port 712, and empty port 713—are equipped with on / off valves. The conveying mechanism 72 is preferably a screw conveyor, with one end connected to the bottom of the settling hopper 71 and the other end extending outside the settling hopper 71. The other end has a second sand discharge port 721. Solid sand particles deposited at the bottom of the settling hopper 71 are conveyed and discharged by the conveying mechanism 72, achieving sand-water separation of concentrated sand. This sand-water separator 7 has a simple structure and facilitates sand-water separation.

[0102] Preferably, the hydrocyclone 4 and the sand collection chamber 5 are directly connected above the sand settling hopper 71 via a riser, so that the concentrated sand in the hydrocyclone 4 and the sand collection chamber 5 can flow into the sand settling hopper 71 of the sand-water separator 7 below by gravity; this avoids the setting of horizontal pipe sections, thereby avoiding the blockage problem of horizontal pipe sections, and can effectively save the floor space, saving 20% ​​or more of the floor space.

[0103] like Figure 8 and Figure 9As shown, the pressure equalization flow distributor 2 includes an inlet main pipe 21 connected to the incoming water pipe and outlet branch pipes 22 connected to the inlet pipe of the hydrocyclone 4. There are at least three outlet branch pipes 22, each connected to a hydrocyclone 4. The flow area (i.e., cross-sectional area) of each outlet branch pipe 22 is equal, and the flow area of ​​the inlet main pipe 21 in each pressure equalization flow distributor 2 is greater than or equal to the sum of the flow areas of its various outlet branch pipes 22. That is, when the flow area of ​​the inlet main pipe 21 is D, the flow area of ​​the outlet branch pipe 22 is d, and the number of outlet branch pipes 22 is N, D ≥ N × d. Further preferably, D = k × N × d, where 1.1 ≤ k ≤ 1.4, which effectively ensures a balanced and stable water inlet for each outlet branch pipe 22 and the hydrocyclone 4, while avoiding energy waste caused by excessive pressure from the incoming water pump.

[0104] Furthermore, when the number of outlet branch pipes 22 and hydrocyclones 4 is 3, it is preferable to use... Figure 8 As shown, outlet branch pipes 22 are spaced apart along the length of the main inlet pipe 21. The three outlet branch pipes 22 are perpendicular to the main inlet pipe 21, located on the same plane, and arranged parallel to each other. This ensures uniform water pressure distribution into the hydrocyclone 4, and is convenient to install and saves space.

[0105] When the number of outlet branch pipes 22 and hydrocyclones 4 is greater than or equal to 4, the following method is adopted: Figure 9 As shown, outlet ends are evenly distributed around the circumference of the main inlet pipe 21 and connected to the branch outlet pipes 22, and the main inlet pipe 21 and each branch outlet pipe 22 are parallel. This effectively ensures that the water flow rate of each branch outlet pipe 22 tends to be consistent, thereby ensuring that the water inlet pressure of each hydrocyclone 4 is balanced and stable.

[0106] See Figure 10 Based on the same inventive objective, this invention also provides a control method for a low-solids-content wastewater cyclone sand removal system. This control method is implemented based on the aforementioned low-solids-content wastewater cyclone sand removal system and includes the following steps:

[0107] S100: Obtain the total inlet water pressure WP1 of the incoming water pipe, and control the number of opening / closing of the first valve 3 and the opening / closing of the corresponding cyclone separator 4 on the parallel branch according to the total inlet water pressure WP1.

[0108] S200, record the cumulative opening time t1 of each first valve 3. When the cumulative opening time t1 of any first valve 3 is greater than or equal to the preset time T0, the second valve 6 on the parallel branch where the first valve 3 is located meets the opening and sand discharge conditions. Conversely, when the cumulative opening time t1 of any first valve 3 is less than the preset time T0, the second valve 6 on the parallel branch where the first valve 3 is located does not meet the opening and sand discharge conditions.

[0109] S300, the sand-water separator 7 operates according to the operating cycle, each operating cycle includes multiple process steps, and the second valve 6 is opened to discharge sand only in the water inlet stage of each operating cycle.

[0110] Preferably, in step S100:

[0111] When the total inlet water pressure WP1 is within the normal operating pressure range P 下限值 ~P 上限值 During operation, open N first valves 3 and their corresponding hydrocyclones 4, where N ≥ 2. That is, at least 2 hydrocyclones 4 should be opened during normal operating water flow.

[0112] When the total inlet water pressure WP1 is less than P 下限值 When, turn on N - The first valve 3 and its corresponding hydrocyclone 4 are used for sand removal, where 1≤N - <N. That is, when the total inlet pressure / inlet flow rate is lower than the lower limit of the normal operating flow rate, some hydrocyclones 4 and their inlets will be automatically shut off, but at least one hydrocyclone 4 must remain open to ensure that the sewage distribution system is not interrupted when the flow rate is low.

[0113] When the total inlet water pressure WP1 is greater than P 上限值 When, turn on N + The first valve 3 and its corresponding hydrocyclone 4 are used for sand removal, wherein N + >N and N + ≥3. That is, when the total inlet water pressure / inlet water volume is higher than the upper limit of the normal operating water volume, more hydrocyclones 4 will be automatically opened to increase the number of operating hydrocyclones 4 and parallel branches, so as to meet the increased water volume and ensure that the inlet water flow / pressure of the operating hydrocyclones 4 is always balanced and stable, and the hydrocyclone sand removal effect is reliable.

[0114] Among them, the normal operating pressure range P 下限值 ~P 上限值 The parameters should be set in the system controller, and can usually be set to 0.08~0.15MPa.

[0115] Furthermore, each hydrocyclone 4 and its corresponding first valve 3 is assigned a priority. For example, some hydrocyclones 4 and their corresponding first valves 3 are set to be normally open for water inlet; others are set to be controlled to start and stop according to changes in total inlet water pressure, and still others have different priorities. For instance, when there are 3 hydrocyclones 4, hydrocyclone 1# is set to be normally open for water inlet, and the other two hydrocyclones 2# and 3# start and stop according to changes in total inlet water pressure; and the priority for opening is: hydrocyclone 2# before hydrocyclone 3#; the priority for closing is: hydrocyclone 3# before hydrocyclone 2#.

[0116] Preferably, in step S200:

[0117] All second valves 6 are set to a cyclical, rotating start sequence. When the rotation reaches the start sequence of any second valve 6, and that second valve 6 meets the conditions for opening and discharging sand, then that second valve 6 opens to discharge sand from the bottom flow. The sand discharge continues for a predetermined sand discharge time T. 排 The second valve 6 will then automatically close. When the starting sequence of the second valve 6 is reached, if the second valve 6 does not meet the conditions for opening and discharging sand, the second valve 6 will not open, and the starting sequence will proceed to the next second valve 6.

[0118] When any first valve 3 is opened, the opening time of the first valve 3 is recorded. When the first valve 3 is closed, the timer stops and the record is not cleared. When the first valve 3 is opened again, the timer continues to be recorded until the cumulative opening time t1 is greater than or equal to the preset time T0. Then the second valve 6 corresponding to the first valve 3 meets the opening and sand discharge conditions. After the second valve 6 that meets the opening and sand discharge conditions is turned into the start-up sequence and opens to discharge sand, the cumulative opening time t1 of the corresponding first valve 3 is cleared and the next round of timing begins.

[0119] When the second valve 6 is opened to discharge sand from the bottom flow, the corresponding first valve 3 should be closed in conjunction with it to avoid fluctuations in the operation of the hydrocyclone 4, reduce the amount of water carried when the concentrated sand is discharged, and reduce the operating load of the sand-water separator 7.

[0120] Preferably, step S200 further includes: when the cumulative opening time t1 of any first valve 3 is greater than 0 and less than the preset time T0, and the duration of a single closure of the first valve 3 exceeds the system-set shutdown time, then the second valve 6 on the parallel branch where the first valve 3 is located also meets the opening and sand discharge conditions. This allows for timely discharge of concentrated sand from the sand collection chamber 5 and cyclone separator 4 on the parallel branch after a short period of operation, preventing concentrated sand from remaining in the sand collection chamber 5 for an extended period due to insufficient cumulative operating time, thus affecting the venting and maintenance of the corresponding parallel branch. Preferably, in step S300:

[0121] The sand-water separator 7 operates through multiple process stages, including an initialization stage, a water inlet stage, a sedimentation stage, a drainage stage, and a sand separation stage, arranged sequentially. Sand is discharged only at the water inlet stage of each operating cycle. The sand-water separator 7 then proceeds with subsequent processing stages. The next operating cycle can only begin after the previous cycle has ended. If the previous operating cycle has not ended, but the next second valve 6 has already met the conditions for opening and discharging sand, the next second valve 6 will wait for a delay. This ensures complete sand-water separation in each operating cycle of the sand-water separator 7, maintains stable sand-water separation performance, and avoids problems such as overflow and operational cycle disruption.

[0122] In summary, this low-solids-content wastewater cyclone sand removal system, equipped with a pressure transmitter 1 to detect the total inlet water pressure and linked to the first valve 3 on the parallel branch of the cyclone separator 4, automatically controls the opening and closing of the cyclone separator 4 branch based on changes in the total inlet water pressure. This effectively solves problems such as unstable flow patterns and poor sand removal effect caused by fluctuations in inlet water volume. The bottom of the cyclone separator 4 is equipped with a sand collection chamber 5 and a second valve 6, which allows for intermittent sand discharge, adapting to the sand removal treatment of low-solids-content wastewater. This effectively increases the sand discharge concentration and reduces the hydraulic load on the sand separator 7. This low-solids-content wastewater cyclone sand removal system operates efficiently and stably, with good sand removal effect.

[0123] By associating the first valve 3 and the second valve 6 on the same parallel branch, the automatic opening of the second valve 6 can be controlled according to the cumulative opening time of the first valve 3, thus realizing the automatic control of intermittent underflow sand discharge. Both the first and second valves are pneumatic valves, and the second valve is a pneumatic clamp valve, which can realize automatic and rapid opening and closing, avoiding problems such as sealing failure caused by sand particles blocking and wear. It can achieve precise dynamic flow regulation and precise underflow sand discharge control, effectively improving the stability and reliability of system operation.

[0124] A backflushing air branch 8 is set in the sand collection chamber 5 to backflush the sand collection chamber 5 and the first sand discharge port 41, which can effectively solve the problems of fine sand caking in the sand collection chamber 5 and blockage of the first sand discharge port 41 at the bottom of the hydrocyclone 4, and ensure smooth intermittent sand discharge.

[0125] The hydrocyclone 4 and sand collection chamber 5 are directly connected above the sand settling hopper 71 via a riser pipe, so that the hydrocyclone 4, sand collection chamber 5 and sand settling hopper 71 are directly connected along the direction of gravity. This improves the structural layout of the equipment, avoids the setting of horizontal pipe sections, and thus avoids the problem of sand accumulation and blockage in horizontal pipe sections. At the same time, it can save more than 20% of the floor space.

[0126] The control method of the low solids content sewage cyclone sand removal system realizes the automatic and coordinated control of three parts: water inlet of cyclone 4, intermittent sand discharge from the underflow of cyclone 4, and sand-water separator 7. This enables the low solids content sewage cyclone sand removal system of this application to achieve fully automated and intelligent control, effectively cope with instantaneous water volume fluctuations, ensure smooth internal flow and stable operating conditions of cyclone 4, guarantee the sand removal effect, and at the same time ensure the system's rapid response, precise control, high efficiency and stable operation.

Claims

1. A control method for a low-solids-content wastewater cyclone sand removal system, characterized in that, include: Pressure transmitter (1) is installed on the water inlet pipe; Multiple hydrocyclones (4) are connected in parallel, and the upper inlet pipe of each hydrocyclone (4) is connected to the water supply pipe via a pressure equalization flow distributor (2); Multiple first valves (3) are respectively provided on the inlet pipe of each of the hydrocyclones (4), and each of the first valves (3) is associated with the pressure transmitter (1); A sand collection chamber (5) is provided at the first sand discharge port (41) at the bottom of each hydrocyclone (4); Multiple second valves (6), each of the sand collection chambers (5) is provided with a second valve (6) at its outlet end; Sand-water separator (7), connected to the outlet end of each of the second valves (6), for sand-water separation of concentrated sand; The controller is electrically connected to the pressure transmitter (1), the first valve (3), the hydrocyclone (4), the second valve (6), and the sand separator (7); Among them, the number of the hydrocyclone (4), the first valve (3), the sand collection chamber (5) and the second valve (6) are equal and are arranged in parallel branches in a one-to-one correspondence, and the parallel branches include more than 3; The control method for the low solids content wastewater cyclone sand removal system includes the following steps: S100: Obtain the total inlet water pressure WP1 of the water pipe, and control the number of opening / closing of the first valve and the opening / closing of the corresponding hydrocyclone according to the total inlet water pressure WP1; S200, record the cumulative opening time t1 of each first valve. When the cumulative opening time t1 of any first valve is greater than or equal to the preset time T0, the second valve on the parallel branch where the first valve is located meets the opening and sand discharge conditions. When the cumulative opening time t1 of any first valve is less than the preset time T0, the second valve on the parallel branch where the first valve is located does not meet the opening and sand discharge conditions. S300, the sand-water separator operates according to an operating cycle, each operating cycle including multiple process steps, and the second valve is opened to discharge sand only during the water inlet stage of each operating cycle.

2. The control method for a low-solids-content wastewater cyclone sand removal system according to claim 1, characterized in that, In step S100: When the total inlet water pressure WP1 is within the normal operating pressure range P 下限值 ~P 上限值 Within this timeframe, open N of the first valves and their corresponding cyclones, where N ≥ 2; When the total inlet water pressure WP1 is less than P 下限值 When, turn on N - For each of the first valves and their corresponding cyclones, 1 ≤ N - <N; When the total inlet water pressure WP1 is greater than P 上限值 When, turn on N + The first valve and its corresponding cyclone separator, N + >N and N + ≥3.

3. The control method for a low-solids-content wastewater cyclone sand removal system according to claim 1, characterized in that, In step S200: All the second valves are set to a cyclical, rotating start sequence. When the rotation reaches the start sequence of any second valve and that second valve meets the conditions for opening and discharging sand, the second valve opens to discharge sand from the bottom flow. The sand discharge continues for a predetermined sand discharge time T. 排 The second valve will then automatically close. When the startup sequence of any second valve is reached, if the second valve does not meet the conditions for opening and discharging sand, the second valve will not open, and the startup sequence will proceed to the next second valve. When any of the first valves is opened, the opening time of the first valve is recorded. When the first valve is closed, the timer stops and the record is not cleared. When the first valve is opened again, the timer continues to be recorded until the cumulative opening time t1 is greater than or equal to the preset time T0. Then the corresponding second valve meets the opening and sand discharge conditions. After the second valve that meets the opening and sand discharge conditions is turned into the start-up sequence and opens to discharge sand, the cumulative opening time t1 of the corresponding first valve is cleared and the next round of timing begins. When the second valve is opened to discharge sand from the bottom flow, the corresponding first valve is closed.

4. The control method for a low-solids-content wastewater cyclone sand removal system according to claim 1 or 3, characterized in that, In step S300: the multiple process steps of the operating cycle include an initialization step, a water inlet step, a sedimentation step, a drainage step, and a sand separation step set in sequence; the second valve is opened to discharge sand only in the water inlet step of each operating cycle, and then the sand-water separator performs subsequent processing. The next operating cycle can only begin after the previous operating cycle is completed; if the previous operating cycle has not ended, but the next second valve has met the conditions for opening and discharging sand, the next second valve will be delayed and wait.

5. A low-solids-content wastewater cyclone sand removal system employing the control method described in any one of claims 1 to 4, characterized in that, All the second valves (6) are interconnected, and each of the second valves (6) is associated with the first valve (3) on the same parallel branch; And / or, all of the cyclones (4) are associated with the pressure transmitter (1); And / or, each of the cyclones (4) is associated with the first valve (3) on the corresponding inlet pipe.

6. The low solids content wastewater cyclone sand removal system according to claim 5, characterized in that, All of the sand collection chambers (5) are provided with a backflush air branch (8), and the backflush air branch (8) is provided with a one-way air inlet valve (81) and a backflush air switch valve (82). The one-way air inlet valve (81) is located at the end of the backflush air branch (8) and is located inside the sand collection chamber (5). All of the backflush air branches (8) are connected to an air compressor. A pressure monitor is provided on the pipeline between the first sand discharge port (41) and the inlet of the sand collection chamber (5), and the pressure monitor is associated with the air purging switch valve (82).

7. The low solids content wastewater cyclone sand removal system according to claim 6, characterized in that, The one-way intake valve (81) includes: Valve body (811), the valve body (811) is a cylindrical structure, one end is a blind end, and the other end is open and connected to the backflush gas branch (8); The valve core (812) is adapted to the inside of the valve body (811) and is axially sealed and slidably disposed inside the valve body (811); An elastic element (813) is disposed inside the valve body (811) and located between the blind end of the valve body (811) and the valve core (812); The valve body (811) has several exhaust holes (8111) distributed circumferentially on its side wall. When the elastic element (813) is reset, it pushes the valve core (812) to block the exhaust holes (8111). When the backflushing gas branch (8) introduces pressurized gas into the sand collection chamber (5), the pressurized gas pushes the valve core (812) to compress the elastic element (813) and open the exhaust holes (8111).

8. The low solids content wastewater cyclone sand removal system according to claim 7, characterized in that, The valve body (811) also includes one or more of the following: The valve body (811) has a limiting part (8112) inside the opening end to limit the valve core (812). When the valve core (812) abuts against the limiting part (8112), the exhaust hole (8111) is blocked. The valve body (811) has a drain hole (8113) on the side wall near the blind end. The valve body (811) has an external thread at one end of its opening, which is connected to the sand collection chamber (5) and / or the backflushing air branch (8) via a threaded joint.

9. The low solids content wastewater cyclone sand removal system according to claim 5, characterized in that, The sand separator (7) includes a settling hopper (71) and a conveying mechanism (72); the settling hopper (71) is provided with an overflow port (711), a drain port (712) and an empty port (713) from top to bottom; the conveying mechanism (72) is a spiral conveying mechanism, one end of which is connected to the bottom of the settling hopper (71), and the other end is provided with a second sand discharge port (721); the hydrocyclone (4) and the sand collection chamber (5) are directly connected above the settling hopper (71) via a riser.

10. The low solids content wastewater cyclone sand removal system according to claim 5, characterized in that: The first valve (3) is a pneumatic gate valve; And / or, the second valve (6) is a pneumatic clamp valve; And / or, the pressure equalization flow distributor (2) includes an inlet main pipe (21) and at least three outlet branch pipes (22), wherein the flow area of ​​the inlet main pipe (21) is greater than or equal to the sum of the flow areas of each outlet branch pipe (22).

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