Environment-friendly concrete mixing station full-scene drainage circulating system and control method

Abstract

The present application belongs to the technical field of wastewater treatment, and more specifically, discloses an environmental protection type concrete mixing station full-scene drainage circulation system and control method. The system comprises a sandstone separator, a high-frequency dehydration screen, a centrifugal separation tank and a uniformity adjusting tank. The high-frequency dehydration screen is arranged at the overflow port of the sandstone separator, and the outlet of the high-frequency dehydration screen is provided with a sand outlet and a mud outlet. The centrifugal separation tank is connected to the mud outlet of the high-frequency dehydration screen, the overflow port is connected to a clean water recycling tank, and the underflow port is connected to a gravity separator. The effective components screened by the gravity separator enter the uniformity adjusting tank. The uniformity adjusting tank is provided with a pneumatic pulse array for circulating stirring of the effective components. The uniformity adjusting tank is provided with a density matching unit for adjusting the concentration of the slurry in the uniformity adjusting tank, and the slurry with standard concentration is input into a concrete mixer as production water to produce concrete. The sand and gravel aggregates in the sewage are classified and recycled, realizing full-process closed-loop utilization and zero emission of waste residue and wastewater.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and more specifically, relates to an environmentally friendly full-scenario drainage circulation system and control method for concrete mixing plants. Background Technology

[0002] As a core production base for infrastructure construction, concrete mixing plants generate a large amount of wastewater during daily operation, including cleaning the mixing unit, washing transport vehicles, and collecting rainwater. The plant's drainage system, a crucial component of the site's infrastructure, is primarily responsible for efficiently collecting, transporting, and treating this production and domestic wastewater to ensure a water-free environment and continuous production.

[0003] In existing technologies, traditional concrete mixing plant drainage systems mostly employ open ditch drainage. This method typically involves excavating open concrete or brick trenches based on the site's topography, utilizing gravity flow to collect various types of wastewater generated on-site and guide them to sedimentation tanks or end collection pits. This open ditch drainage method was widely used in early concrete mixing plant construction due to its simple structure, convenient construction, and low initial construction costs, and remains a common wastewater discharge method today.

[0004] However, in practical applications, this traditional open ditch sewage discharge method has many insurmountable drawbacks. First, it is difficult and costly to operate and maintain. Because the wastewater from the mixing plant contains a large amount of sand, gravel aggregate, and cement slurry, it is very easy for these materials to settle and harden at the bottom of the ditch, leading to frequent blockages. Once blocked, it not only causes sewage overflow and seriously damages the civilized image of the construction site, but also requires a lot of manpower for regular dredging and cleaning, increasing management difficulty and labor costs. Second, it poses a serious environmental pollution risk. Wastewater from the mixing plant usually contains various concrete admixtures. Traditional open ditch systems often lack adequate seepage prevention and sealing measures. If this wastewater containing chemical agents is discharged directly without treatment or seeps through the ditch, it will cause serious damage to the surrounding soil environment, groundwater, and natural ecosystem. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides an environmentally friendly full-scenario drainage recycling system and control method for concrete mixing plants. By employing a sand and gravel separator, a high-frequency dewatering screen, and a centrifugal separator, wastewater undergoes multi-stage physical sorting and solid-liquid separation. Furthermore, a homogenizing tank equipped with a pneumatic pulse array dynamically homogenizes the recycled waste slurry. This solves the technical problems of traditional mixing plant drainage systems, such as ditch blockage due to mud and sand deposition and the direct discharge of admixture-containing wastewater, which damages the ecological environment. The system graded and recycled sand and gravel aggregates from the wastewater and ensures that the concentrated waste slurry, in a sediment-free and controllable concentration state, is directly reused as a raw material for concrete mixing, thereby achieving a closed-loop utilization and zero-discharge environmental protection effect for waste residue and wastewater throughout the entire process.

[0006] To achieve the above objectives, according to a first aspect of the present invention, an environmentally friendly full-scenario drainage and circulation system for a concrete mixing plant is provided, comprising: a sand and gravel separator, a high-frequency dewatering screen, a centrifugal separation tank, and a homogenizing tank.

[0007] The sand and gravel separator pre-treats wastewater from the outlet cleaning, tanker cleaning, site wastewater, and silo drainage.

[0008] The high-frequency dewatering screen is located at the overflow port of the sand and gravel separator. The water pretreated by the sand and gravel separator is fed into the high-frequency dewatering screen. The outlet of the high-frequency dewatering screen is provided with a sand outlet and a mud outlet, which output fine sand and muddy water respectively.

[0009] The centrifugal separator is connected to the sludge outlet of the high-frequency dewatering screen to separate the sludge and water output from the high-frequency dewatering screen. The overflow outlet of the centrifugal separator is connected to a clean water recycling tank, and the bottom outlet is connected to a gravity separator.

[0010] The gravity separator collects the concentrated waste slurry output from the bottom outlet of the centrifugal separator and screens the particles therein. The screened effective components enter the homogenization tank.

[0011] The homogenizing tank is equipped with a pneumatic pulse array, which includes multiple pulse nozzles arranged in layers in the homogenizing tank to circulate and stir the effective components in the homogenizing tank.

[0012] The homogenization tank is equipped with a density proportioning unit to assist in adjusting the concentration of the slurry in the homogenization tank. The slurry with the required concentration is then used as production water and fed into the concrete mixer to produce concrete.

[0013] Furthermore, the overflow port of the sand and gravel separator is connected to the feed box of the high-frequency dewatering screen through a chute or pipe. The high-frequency dewatering screen is equipped with a high-pressure spray water pipe to wash the separated fine sand, avoid mud covering the sand, and improve the cleanliness of the fine sand.

[0014] Furthermore, the fine sand separated from the high-frequency dewatering screen is directly transported to the raw material warehouse for concrete production, and the separated mud and water enter the intermediate buffer tank, from which the mud and water are pumped into the centrifugal separation tank by the slurry pump.

[0015] The centrifugal separator is a hydrocyclone with a conical structure. It has a sand discharge nozzle in its underflow outlet. The diameter of the sand discharge nozzle is variable. The underflow concentration is controlled by adjusting the diameter of the sand discharge nozzle so as to output high-concentration waste slurry.

[0016] Furthermore, the gravity separator is a spiral chute gravity separator. After the high-concentration waste slurry output from the bottom of the centrifugal separator enters the gravity separator, it is separated according to the density difference between effective particles and ineffective particles.

[0017] The effective particles include unhydrated cement particles and fine sand and gravel powder, and the ineffective particles include hydrated cement gel, clay impurities, and flocs. The density of the effective particles is greater than the density of the ineffective particles.

[0018] The effective particles, due to their higher density, will move along the inner ring of the spiral chute in the gravity separator, while the ineffective particles, due to their lower density, will float on the surface of the water flow and be thrown towards the outer ring of the spiral chute.

[0019] Furthermore, after the separated water containing effective particles enters the homogenizing tank, it is intermittently stirred by alternating jets through pulse nozzles installed therein, thereby preventing the particles from settling and caking.

[0020] The homogenization tank is a slender cylindrical tank with its inlet located at the top and its outlet located at the bottom. The top is also equipped with an overflow port to prevent overflow when the tank is full. The pulse nozzle has three layers: an arch-breaking layer at the bottom, a main mixing layer in the middle, and a micro-disturbance layer at the top. Each layer has multiple nozzles.

[0021] The arch-breaking layer is used to target heavy particles and prevent their deposition. The main mixing layer is used to target the concentrated slurry and carry it to the top to achieve vertical circulation. The micro-disturbance layer is used to target the inner surface of the liquid surface to prevent particles from forming a crust on the inner wall of the homogenization tank at the liquid surface.

[0022] Furthermore, the density proportioning unit includes a test tube located at the bottom of the homogenization tank. The test tube is equipped with a test pump and a three-way valve. One end of the three-way valve is connected to a weighing scale, and the other end flows back into the homogenization tank. The outlet end of the test pump is equipped with a densitometer and a flow meter. The densitometer is used to measure the density of the water output from the bottom of the homogenization tank, and the flow meter is used to measure the flow rate in the test tube to control the frequency of the test pump and avoid the liquid flow rate in the test tube being too slow, which would cause particle deposition and affect the degree.

[0023] The density proportioning unit also includes a clean water supply valve, which is connected to the homogenization tank. The liquid density in the homogenization tank is controlled by adjusting the flow rate of the separated water containing effective particles and the clean water input into the homogenization tank.

[0024] Furthermore, after the liquid density in the homogenizing tank is adjusted to a constant value, it is output to the concrete mixer within a fixed density range. The slurry output from the homogenizing tank is used as the water required for concrete mixing. The effective particles in the slurry are directly used as raw materials for mixing, and the amount of raw materials input is reduced accordingly.

[0025] According to a second aspect of the present invention, a control method for a full-scene drainage circulation system of an environmentally friendly concrete mixing plant is provided, comprising the following steps:

[0026] S100: Collect wastewater from the mixing plant, introduce it into the sand and gravel separator for pretreatment to separate large particles of sand and gravel, control the opening of the overflow chute or pipeline, connect the water to the high-frequency dewatering screen, start the high-pressure spray to wash the fine sand to improve the cleanliness, and then send it into the raw material warehouse. The mud and water are introduced into the intermediate buffer tank.

[0027] S200: Add clean water to the intermediate buffer tank to dilute the mud and water, wash off impurity ions on the surface of the particles, start the slurry pump to pump the mud and water into the centrifugal separation tank, adjust the diameter of the sand discharge nozzle to control the underflow concentration and output high-concentration waste slurry, and filter the overflow containing impurities for use in mixing plant vehicle washing and site cleaning.

[0028] S300: High-concentration waste slurry is introduced into a spiral chute gravity separator, which separates the effective and ineffective particles by utilizing the density difference between them. The effective particles move along the inner ring of the chute, while the ineffective particles float to the surface and are thrown to the outer ring, thus accurately achieving the classification and screening of the two types of particles.

[0029] S400: Separated water containing effective particles is pumped into a homogenizing tank, while separated water containing ineffective particles is sent to a filter press for treatment. The sludge cake is transported off-site, and the filtrate is discharged or reused after meeting the standards. The pneumatic pulse array is activated to alternately spray air and stir in layers to prevent particle deposition, stratification, and crusting on the inner wall.

[0030] S500: Open the density mixing unit, start the test pump and three-way valve, monitor the data through the density meter and flow meter, and adjust the pump frequency to avoid particle deposition. Adjust the clean water supply valve to control the inlet water flow and adjust the slurry concentration in the tank to the set range and keep it stable.

[0031] S600, qualified slurry is fed into the concrete mixer, and the amount of raw materials input is reduced according to the effective particle content, so as to realize the closed-loop utilization and zero discharge of waste residue and wastewater.

[0032] Further, in step S400, the pulse force of the stratified nozzle is:

[0033]

[0034] in, The pulse force of the nozzle in the i-th layer is given by the pulse force of the single pulse. i = 1, 2, 3 correspond to the arch-breaking layer, the main mixing layer, and the micro-perturbation layer, respectively.

[0035] As the reference jet pressure,

[0036] The nozzle exit cross-sectional area is...

[0037] For layered pulse coefficients,

[0038] To homogenize the density of the slurry in the regulating tank,

[0039] The dynamic viscosity of the slurry.

[0040] To adjust the inner diameter of the homogenization tank,

[0041] Install the tilt angle for the stratified nozzle;

[0042] Through exponential function Strengthening the coupling relationship between slurry density and viscosity, logarithmic function Smoothly adapts to differences in tank size, using trigonometric functions By correcting the influence of nozzle tilt angle on the force, the force of the layered nozzles can be finely and differentially controlled. The bottom layer outputs a high-intensity force to break up the deposition of heavy particles, the middle layer adapts the force to build a circulating flow field, and the top layer uses a gentle force to suppress the crust formation on the inner wall, thus avoiding the problems of local stirring failure and excessive energy consumption.

[0043] Furthermore, jet interval cycle for:

[0044]

[0045] in, This is the structural correction factor.

[0046] The average flow velocity of the slurry.

[0047] The average pulse force of the three-layer nozzle.

[0048] The function is a hyperbolic cosine function, which suppresses flow overshoot caused by abrupt density changes.

[0049] This is a correction factor for ambient temperature.

[0050] During operation, multi-dimensional parameters are collected in real time and substituted into formulas to achieve nonlinear dynamic correction of the interval period. Hyperbolic cosine function is used to smooth the interference caused by temperature fluctuations, and arctangent function is used to optimize the adaptation response when the slurry characteristics change abruptly. When the slurry concentration and viscosity change, the interval period is automatically and precisely controlled to ensure the homogeneity of the slurry under different working conditions and improve the stability of system operation.

[0051] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0052] 1. The environmentally friendly full-scenario drainage recycling system for concrete mixing plants of this invention employs a sand and gravel separator, a high-frequency dewatering screen, and a centrifugal separator to perform multi-stage physical sorting and solid-liquid separation of wastewater. It also utilizes a homogenizing tank equipped with a pneumatic pulse array to dynamically homogenize the recycled waste slurry. This solves the technical problems of traditional mixing plant drainage systems, such as ditch blockage due to mud and sand deposition and direct discharge of wastewater containing admixtures that damages the ecological environment. The system graded and recycled sand and gravel aggregates from the wastewater and ensured that the concentrated waste slurry, in a sediment-free and controllable concentration state, was directly reused as a raw material for concrete mixing, thereby achieving a closed-loop utilization and zero-discharge environmental protection effect for waste residue and wastewater throughout the entire process.

[0053] 2. The environmentally friendly full-scene drainage circulation system for concrete mixing plants of the present invention, in the centrifugal separator, controls the diameter of the sand discharge nozzle at the lowest end of the cone. When the diameter decreases, the discharge resistance increases, forcing more water to flow upwards from the overflow outlet, thus increasing the concentration of the underflow; when the diameter increases, the discharge resistance decreases, and more water carrying fine sludge will be flushed directly from the bottom, thus decreasing the concentration of the underflow. This achieves the purpose of regulating the underflow concentration of the centrifugal separator.

[0054] 3. The environmentally friendly concrete mixing plant full-scene drainage circulation system of the present invention controls the density of the slurry in the homogenizing tank to maintain a fixed density that is not easy to clump and is easy to transport. Then it is transported to the concrete mixer as raw material for mixing. The amount of each additional raw material can be calculated. When preparing concrete, it can be added directly according to the fixed amount without having to calculate the amount of raw materials to be added multiple times. This not only realizes the recycling of waste materials, but also saves the cost of calculating materials. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of an environmentally friendly concrete mixing plant full-scene drainage circulation system according to an embodiment of the present invention;

[0056] Figure 2 This is a schematic diagram of the discharge port structure of an environmentally friendly concrete mixing plant full-scene drainage circulation system according to an embodiment of the present invention;

[0057] Figure 3 This is a schematic diagram of the silo structure of an environmentally friendly concrete mixing plant full-scene drainage circulation system according to an embodiment of the present invention;

[0058] Figure 4 This is a plan view of the silo structure layout of an environmentally friendly concrete mixing plant full-scene drainage circulation system according to an embodiment of the present invention;

[0059] Figure 5 This is a schematic diagram of the control method for a full-scene drainage circulation system of an environmentally friendly concrete mixing plant according to an embodiment of the present invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0061] Example 1

[0062] like Figure 1As shown, this embodiment of the invention provides an environmentally friendly full-scenario drainage and circulation system for a concrete mixing plant, including: a sand and gravel separator, a high-frequency dewatering screen, a centrifugal separator, and a homogenizing tank. The sand and gravel separator pre-treats wastewater from the discharge port cleaning, tanker cleaning, site wastewater, and silo drainage. The high-frequency dewatering screen is located at the overflow port of the sand and gravel separator; the pre-treated water from the sand and gravel separator enters the high-frequency dewatering screen. The outlet of the high-frequency dewatering screen has a sand outlet and a mud outlet, outputting fine sand and muddy water respectively. The centrifugal separator is connected to the mud outlet of the high-frequency dewatering screen to separate the muddy water output from the high-frequency dewatering screen. The overflow port of the centrifugal separator is connected to a clean water recycling tank, and the underflow port is connected to a gravity separator. The gravity separator collects the concentrated waste slurry output from the underflow port of the centrifugal separator and screens the particles within it; the screened effective components enter the homogenizing tank. The homogenizing tank is equipped with a pneumatic pulse array, which includes multiple pulse nozzles arranged in layers within the homogenizing tank to circulate and stir the effective components in the tank. The homogenizing tank also includes a density proportioning unit to assist in adjusting the concentration of the slurry. Slurry with the required concentration is then used as production water in the concrete mixer for concrete production. By employing a sand and gravel separator, a high-frequency dewatering screen, and a centrifugal separator for multi-stage physical sorting and solid-liquid separation of wastewater, combined with dynamic homogenization treatment of the recycled waste slurry using the pneumatic pulse array-equipped homogenizing tank, the technical problems of traditional mixing plant drainage systems—such as ditch blockage due to mud and sand deposition and direct discharge of admixture-containing wastewater damaging the ecological environment—are solved. The system allows for the graded recovery of sand and gravel aggregates from wastewater and ensures that the concentrated waste slurry, in a sediment-free and controlled-concentration state, is directly reused as a raw material in concrete mixing, thus achieving a closed-loop utilization and zero-discharge environmental protection effect for waste residue and wastewater.

[0063] like Figure 2 As shown, when collecting the cleaning wastewater from the discharge port, the open ditch drainage design at the discharge port is eliminated. Instead, a 2.5% reverse longitudinal slope is set on the ground at the discharge port of the mixer, and the cleaning wastewater is discharged from the outlet behind the discharge port partition wall through the drainage ditch into the sand and gravel separator.

[0064] Wastewater from the tanker cleaning process is collected and discharged into the sand and gravel separator via a drainage ditch.

[0065] Wastewater from the site is collected by setting up a longitudinal slope for the ground and pre-buried pipes, and then flows into a collection well. When the site cleaning water and rainwater contain only a small amount of silt, they are recycled after sedimentation or discharged directly through drainage ditches. When material leakage occurs on the site and there are a large amount of concrete residue or fly ash, it is directly discharged into the sand and gravel separator.

[0066] like Figure 3 , 4As shown, when collecting the drainage from the silo, the sand and gravel generally contain a large amount of water. The silo floor is designed with a 2.5% reverse drainage longitudinal slope. Two crushed stone blind ditches are set in the fine aggregate silo, eliminating the traditional open ditch at the silo opening. Reverse drainage is used to allow water to flow out from the drainage hole on the back wall and be collected in the sand and gravel separator through the drainage ditch.

[0067] The overflow port of the sand and gravel separator is connected to the feed box of the high-frequency dewatering screen through a chute or pipe. The high-frequency dewatering screen is equipped with a high-pressure spray water pipe to wash the separated fine sand, avoid mud covering the sand and improve the cleanliness of the fine sand.

[0068] The fine sand separated by the high-frequency dewatering screen is directly transported to the raw material warehouse for concrete production, while the separated muddy water enters the intermediate buffer tank. A slurry pump then pumps the muddy water from the intermediate buffer tank into a centrifugal separator. The centrifugal separator is a conical hydrocyclone with a sand-collecting nozzle at its underflow outlet. The diameter of the sand-collecting nozzle is variable, and the underflow concentration is controlled by adjusting the diameter of the sand-collecting nozzle to output high-concentration waste slurry.

[0069] Understandably, in a centrifuge, by controlling the diameter of the sand discharge nozzle at the lowest point of the cone, a smaller diameter increases the discharge resistance, forcing more water to flow upwards from the overflow outlet, thus increasing the concentration of the underflow. Conversely, a larger diameter decreases the discharge resistance, allowing more water carrying fine sludge to be flushed directly out from the bottom, thus decreasing the concentration of the underflow. This is how the concentration of the underflow in the centrifuge is adjusted.

[0070] The water collected in the water reuse tank is not pure water, but water that has been simply filtered and can be used for washing cars or cleaning the site.

[0071] In a preferred embodiment, before the mud-water separated by the high-frequency dewatering screen enters the intermediate buffer tank, it is diluted with clean water to wash away and dissolve the high concentration of additive ions and chloride ions attached to the surface of the particles in the mud-water. After entering the centrifugal separation tank, the additive ions and chloride ions are discharged with the overflow water and then undergo separate chemical treatment to meet the standards.

[0072] The gravity separator is a spiral chute gravity separator. After the high-concentration waste slurry from the bottom of the centrifugal separator enters the gravity separator, it is separated based on the density difference between effective and ineffective particles. The effective particles include unhydrated cement particles and fine sand and gravel powder, while the ineffective particles include hydrated cement gel, clay impurities, and flocculants. The density of the effective particles is greater than that of the ineffective particles. Due to their higher density, the effective particles move along the inner ring of the spiral chute in the gravity separator, while the ineffective particles, due to their lower density, float on the surface of the water flow and are thrown towards the outer ring of the spiral chute.

[0073] The separated water containing effective particles obtained by the gravity separator is directly pumped into the homogenization tank for processing, while the separated water containing ineffective particles is collected and transported to the filter press for solid-liquid separation. The sludge cake containing ineffective particles is transported off-site for processing, and then the filtrate containing high concentrations of additive residues and harmful ions is chemically treated to meet the standards.

[0074] After the separated water containing effective particles enters the homogenizing tank, it is intermittently agitated by alternating jets from pulse nozzles, thereby preventing particle sedimentation and caking. The homogenizing tank is a slender cylindrical tank with its inlet at the top and outlet at the bottom. An overflow port is also provided at the top to prevent overflow. The pulse nozzles consist of three layers: a bottom arch-breaking layer, a middle main mixing layer, and a top micro-disturbance layer, each with multiple nozzles. The arch-breaking layer targets heavy particles to prevent their deposition; the main mixing layer targets the concentrated slurry, carrying it to the top for circulation; and the micro-disturbance layer targets the inner surface of the liquid, preventing particles from forming a crust on the inner wall of the homogenizing tank.

[0075] The density proportioning unit includes a test tube located at the bottom of the homogenization tank. The test tube is equipped with a test pump and a three-way valve. One end of the three-way valve is connected to a weighing scale, and the other end returns to the homogenization tank. A densitometer and a flow meter are installed at the outlet of the test pump. The densitometer measures the density of the water output from the bottom of the homogenization tank, and the flow meter measures the flow velocity in the test tube to provide feedback control of the test pump frequency, preventing excessively slow liquid flow in the test tube from causing particle deposition and affecting the density reading. The density proportioning unit also includes a clean water supply valve connected to the homogenization tank. By adjusting the flow rates of the separated water containing effective particles and the clean water input to the homogenization tank, the liquid density in the homogenization tank is controlled.

[0076] As a further preferred embodiment, after the liquid density in the homogenizing tank is adjusted to a constant value, it is output to the concrete mixer within a fixed density range. The slurry output from the homogenizing tank is used as the water required for concrete mixing, and the effective particles in the slurry are directly used as raw materials for mixing, thereby reducing the amount of raw materials input accordingly.

[0077] Understandably, by controlling the density of the slurry in the homogenizing tank to maintain a fixed density that is not prone to clumping and is easy to transport, and then transporting it to the concrete mixer as raw material for mixing, the amount of each additional raw material can be calculated. When preparing concrete, it can be added directly according to the fixed amount, without having to calculate the amount of raw materials to be added multiple times. This not only realizes the recycling of waste materials, but also saves the cost of calculating materials.

[0078] Example 2

[0079] like Figure 5 As shown in the figure, this invention provides a control method for a full-scenario drainage circulation system of an environmentally friendly concrete mixing plant, specifically including the following steps:

[0080] S100: Collect wastewater from the mixing plant, introduce it into the sand and gravel separator for pretreatment to separate large particles of sand and gravel, control the opening of the overflow chute or pipeline, connect the water to the high-frequency dewatering screen, start the high-pressure spray to wash the fine sand to improve the cleanliness, and then send it into the raw material warehouse. The mud and water are introduced into the intermediate buffer tank.

[0081] S200: Add clean water to the intermediate buffer tank to dilute the mud and water, wash off impurity ions on the surface of the particles, start the slurry pump to pump the mud and water into the centrifugal separation tank, adjust the diameter of the sand discharge nozzle to control the underflow concentration and output high-concentration waste slurry, and filter the overflow containing impurities for use in mixing plant vehicle washing and site cleaning.

[0082] S300: High-concentration waste slurry is introduced into a spiral chute gravity separator, which separates the effective and ineffective particles by utilizing the density difference between them. The effective particles move along the inner ring of the chute, while the ineffective particles float to the surface and are thrown to the outer ring, thus accurately achieving the classification and screening of the two types of particles.

[0083] S400: Separated water containing effective particles is pumped into a homogenizing tank, while separated water containing ineffective particles is sent to a filter press for treatment. The sludge cake is transported off-site, and the filtrate is discharged or reused after meeting the standards. The pneumatic pulse array is activated to alternately spray air and stir in layers to prevent particle deposition, stratification, and crusting on the inner wall.

[0084] S500: Open the density mixing unit, start the test pump and three-way valve, monitor the data through the density meter and flow meter, and adjust the pump frequency to avoid particle deposition. Adjust the clean water supply valve to control the inlet water flow and adjust the slurry concentration in the tank to the set range and keep it stable.

[0085] S600, qualified slurry is fed into the concrete mixer, and the amount of raw materials input is reduced according to the effective particle content, so as to realize the closed-loop utilization and zero discharge of waste residue and wastewater.

[0086] In step S100, various types of wastewater, including wastewater from the mixing plant's discharge outlet, tanker cleaning, site flushing, and silo drainage, are collected and uniformly channeled into a dedicated collection tank for consolidation and buffering to prevent indiscriminate discharge and spread. The wastewater in the collection tank is then uniformly introduced into a sand and gravel separator. Through the internal screening structure, large particles of sand and gravel are efficiently separated from the wastewater. Simultaneously, the chute or pipe at the overflow port of the sand and gravel separator is smoothly opened to ensure that the pretreated water is accurately fed into the high-frequency dewatering screen's feed box. At the same time, the high-pressure spray pipe on the dewatering screen is activated to specifically wash the separated fine sand with appropriate water pressure, thoroughly removing the mud and impurities adhering to the surface of the fine sand and improving its cleanliness. The washed fine sand is directly transported to the raw material warehouse for later use, while the mud and water produced by the dewatering screen are introduced into an intermediate buffer tank to prepare for subsequent dilution treatment.

[0087] In step S200, clean water is slowly injected into the intermediate buffer tank, controlling the ratio of clean water to mud-water to fully dilute and stir the mud-water, efficiently washing away high-concentration additive ions and chloride ions adhering to the surface of the mud-water particles. After uniform dilution, the slurry pump is started to uniformly pump the mixed mud-water in the buffer tank into a conical centrifugal separator. By adjusting the diameter of the variable-diameter sand discharge nozzle at the bottom outlet of the separator, the discharge resistance is changed to precisely control the bottom flow concentration, ensuring that the output high-concentration waste slurry meets the requirements. The impurity-containing water discharged from the overflow outlet of the separator is connected to the clean water reuse tank. After removing suspended impurities through a simple filtration device, it is used for auxiliary operations such as tanker cleaning and site flushing at the mixing plant, realizing primary water recycling.

[0088] In step S300, the high-concentration waste slurry output from the centrifugal separator is smoothly introduced into a spiral chute gravity separator through a conveying pipeline. Utilizing the combined effect of centrifugal force and gravity generated by the spiral structure inside the separator, effective and ineffective particles are separated based on their density difference. The denser effective particles settle close to the inner ring of the spiral chute, while the less dense ineffective particles float on the surface and are thrown towards the outer ring by centrifugal force. This precise and efficient screening of the two types of particles lays the foundation for subsequent recycling and impurity treatment.

[0089] In step S400, the separated water containing effective particles, separated by the gravity separator, is pumped at a constant speed into a homogenization tank for later use. Simultaneously, the separated water containing ineffective particles is collected and transported to a filter press for deep solid-liquid separation. The resulting sludge cake is sealed, packaged, and transported for disposal. The filtrate is introduced into a dedicated treatment tank, where it undergoes chemical neutralization and purification to meet standards before being discharged or recycled. Simultaneously, a pneumatic pulse array within the homogenization tank is activated, controlling the pulse nozzles in the bottom arch-breaking layer, the middle main mixing layer, and the top micro-disturbance layer to alternately spray air, intermittently agitating the water within the tank. This effectively prevents the deposition of heavy particles, slurry stratification, and crust formation on the liquid surface of the tank's inner wall.

[0090] In step S400, when starting the pneumatic pulse array in the homogenization tank, it is necessary to combine the characteristics of the slurry in the tank, the function of the nozzle level and the operating conditions of the equipment, and set the nozzle operating parameters through a complex control formula with multi-parameter coupling, dynamically adjust the jet intensity and interval period, ensure the stirring effect to completely prevent particle deposition, slurry stratification and inner wall crusting, and take into account both operational stability and reasonable energy consumption.

[0091] In step S400, the pulse force of the stratified nozzle is:

[0092]

[0093] in, The pulse force of the nozzle in the i-th layer is given by the pulse force of the single pulse. i = 1, 2, 3 correspond to the arch-breaking layer, the main mixing layer, and the micro-perturbation layer, respectively.

[0094] As the reference jet pressure,

[0095] The nozzle exit cross-sectional area is...

[0096] For layered pulse coefficients,

[0097] To homogenize the density of the slurry in the regulating tank,

[0098] The dynamic viscosity of the slurry.

[0099] To adjust the inner diameter of the homogenization tank,

[0100] Install the tilt angle for the stratified nozzle;

[0101] Through exponential function Strengthening the coupling relationship between slurry density and viscosity, logarithmic function Smoothly adapts to differences in tank size, using trigonometric functions By correcting the influence of nozzle tilt angle on the force, the force of the layered nozzles can be finely and differentially controlled. The bottom layer outputs a high-intensity force to break up the deposition of heavy particles, the middle layer adapts the force to build a circulating flow field, and the top layer uses a gentle force to suppress the crust formation on the inner wall, thus avoiding the problems of local stirring failure and excessive energy consumption.

[0102] Jet interval cycle for:

[0103]

[0104] in, This is the structural correction factor.

[0105] The average flow velocity of the slurry.

[0106] The average pulse force of the three-layer nozzle.

[0107] The function is a hyperbolic cosine function, which suppresses flow overshoot caused by abrupt density changes.

[0108] This is a correction factor for ambient temperature.

[0109] During operation, by collecting multi-dimensional parameters in real time and substituting them into the formula, the non-linear dynamic correction of the interval period is realized. The interference caused by the smooth temperature fluctuation is eliminated by means of the hyperbolic cosine function, and the adaptation response when the slurry characteristics change suddenly is optimized by the arctangent function. When the slurry concentration and viscosity change, the accurate regulation of the interval period is automatically realized, ensuring the homogeneity of the slurry under different working conditions and improving the operation stability of the system.

[0110] It can be understood that based on the pulsed force of the stratified nozzle and the jet interval period, the pneumatic pulse array can realize the coordinated dynamic regulation of the force of the three-layer nozzle and the jet interval. The bottom arch-breaking layer impacts the sediment particles at the bottom of the tank with the adapted force calculated by the formula. The middle main mixing layer drives the thick slurry to form an up-and-down circulating flow field. The top micro-perturbation layer inhibits the crust formation on the inner wall at the liquid surface. At the same time, through real-time feedback correction of parameters, the mixing failure caused by the change of the slurry state is avoided, taking into account the mixing effect, operation stability and energy consumption optimization, providing a uniform and stable material basis for subsequent density ratio and slurry recycling.

[0111] In step S500, the density ratio unit supporting the homogeneous regulation tank is started, and the test pump and three-way valve on the test pipe are started. The test pump pumps the slurry at the bottom of the tank to the detection circuit, and the density of the slurry is monitored in real time by the densitometer, and the flow rate data in the pipe is collected synchronously by the flow meter. According to the monitored data feedback, the operation frequency of the test pump is adjusted to avoid the influence of particle deposition due to too slow flow rate on the detection accuracy. At the same time, the opening degree of the clean water replenishing valve is adjusted to accurately control the input flow rates of the separated water containing effective particles and the clean water, and the slurry concentration in the tank is stably adjusted to the set range meeting the requirements of concrete production, ensuring the adaptability of subsequent production.

[0112] In step S500, to achieve the accurate coupling control of the input flow rates of the separated water containing effective particles and the clean water, a non-linear complex control formula needs to be constructed based on the real-time monitoring data of the slurry density in the tank, the viscosity change and the flow rate feedback signal. The flow rate parameters are corrected by the cooperation of multiple functions to ensure that the slurry concentration in the tank is stable within the set range, and at the same time, the interference of particle deposition on the flow rate regulation is suppressed.

[0113] Among them, the flow rate of the separated water containing effective particles is:

[0114]

[0115] Among them, is the real-time adjusted flow rate of the separated water containing effective particles,

[0116] is the reference flow rate of the separated water,

[0117] is the first kind of Bessel function of the third order, which is used for non-linear coupling of the slurry density and smoothly correcting the influence of the slurry characteristics on the flow rate,

[0118] This is the density deviation attenuation coefficient, used to amplify the density deviation from the set value. Flow rate adjustment sensitivity at that time

[0119] The change rate of slurry density

[0120] The maximum allowable rate of density change,

[0121] The function is a hyperbolic cosine function, which suppresses flow overshoot caused by abrupt density changes.

[0122] The average flow velocity of the slurry.

[0123] The critical flow velocity is...

[0124] The flow rate is an inverse cosine function to prevent excessively high flow rates from causing turbulent slurry flow or excessively low flow rates from causing particle deposition.

[0125] The amount of clean water to replenish is:

[0126]

[0127] in, To replenish the clean water supply in real time,

[0128] The replenishment volume is based on the clean water standard.

[0129] Using a gamma function, it precisely adapts to the ratio of slurry viscosity to density, optimizing the water replenishment accuracy under both low and high concentration conditions.

[0130] This is the density deviation weighting coefficient.

[0131] It is a hyperbolic secant function.

[0132] This refers to the actual pressure difference before and after the clean water supply valve.

[0133] This represents the maximum permissible pressure difference.

[0134] In step S500, the effective particle separation water flow rate and the clean water makeup water flow rate are corrected using a flow coupling balance correction formula, specifically:

[0135]

[0136] in, For fine-tuning the flow rate correction amount,

[0137] This is the structural correction factor.

[0138] The attenuation coefficient is...

[0139] To adjust the time;

[0140] Understandably, the synergistic effect of logarithmic, sine, and exponential functions can quickly suppress fluctuations during flow regulation, ensure that the slurry density rapidly returns to the set value and remains stable, and avoid interference from particle deposition on the accuracy of flow regulation, thus providing a stable material basis for subsequent slurry reuse.

[0141] In step S600, after the density of the slurry in the homogenizing tank stabilizes within the set range, the qualified slurry is sent to the concrete mixer through the delivery pipeline and used as production water in concrete preparation. Based on the content of effective particles in the slurry, the input of corresponding concrete raw materials is accurately calculated and reduced, ensuring that the concrete quality meets standards while achieving closed-loop utilization and zero discharge of waste residue and wastewater throughout the entire process. During daily operation, the operating status of each piece of equipment is regularly checked, residual impurities in the screening and separation equipment are cleaned promptly, and testing instruments such as density meters and flow meters are calibrated regularly to ensure the continuous and stable operation of the entire circulation system, balancing environmental protection and production efficiency.

[0142] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An environmentally friendly full-scenario drainage circulation system for concrete mixing plants, characterized in that, include: Sand and gravel separator, high-frequency dewatering screen, centrifugal separator and homogenizing tank; The sand and gravel separator pre-treats wastewater from the outlet cleaning, tanker cleaning, site wastewater, and silo drainage. The high-frequency dewatering screen is located at the overflow port of the sand and gravel separator. The water pretreated by the sand and gravel separator is fed into the high-frequency dewatering screen. The outlet of the high-frequency dewatering screen is provided with a sand outlet and a mud outlet, which output fine sand and muddy water respectively. The centrifugal separator is connected to the sludge outlet of the high-frequency dewatering screen to separate the sludge and water output from the high-frequency dewatering screen. The overflow outlet of the centrifugal separator is connected to a clean water recycling tank, and the bottom outlet is connected to a gravity separator. The gravity separator collects the concentrated waste slurry output from the bottom outlet of the centrifugal separator and screens the particles therein. The screened effective components enter the homogenization tank. The homogenizing tank is equipped with a pneumatic pulse array, which includes multiple pulse nozzles arranged in layers in the homogenizing tank to circulate and stir the effective components in the homogenizing tank. The homogenization tank is equipped with a density proportioning unit to assist in adjusting the concentration of the slurry in the homogenization tank, and the slurry with the required concentration is used as production water and input into the concrete mixer to produce concrete. After the separated water containing effective particles enters the homogenization and conditioning tank, it is intermittently stirred by alternating jets through the pulse nozzles installed therein, thereby preventing the particles from settling and caking. The homogenization tank is a slender cylindrical tank with its inlet located at the top and its outlet located at the bottom. The top is also equipped with an overflow port to prevent overflow when the tank is full. The pulse nozzle has three layers: an arch-breaking layer at the bottom, a main mixing layer in the middle, and a micro-disturbance layer at the top. Each layer has multiple nozzles. The arch-breaking layer is used to target heavy particles and prevent their deposition. The main mixing layer is used to target the concentrated slurry and carry it to the top to achieve vertical circulation. The micro-disturbance layer is used to target the inner surface of the liquid surface to prevent particles from forming a crust on the inner wall of the homogenization tank at the liquid surface.

2. The environmentally friendly full-scene drainage circulation system for concrete mixing plants according to claim 1, characterized in that, The overflow port of the sand and gravel separator is connected to the feed box of the high-frequency dewatering screen through a chute or pipe. The high-frequency dewatering screen is equipped with a high-pressure spray water pipe to wash the separated fine sand, avoid mud covering the sand and improve the cleanliness of the fine sand.

3. The environmentally friendly full-scene drainage circulation system for concrete mixing plants according to claim 2, characterized in that, The fine sand separated by the high-frequency dewatering screen is directly transported to the raw material warehouse for concrete production, and the separated mud and water enter the intermediate buffer tank. The mud and water are then pumped from the intermediate buffer tank into the centrifugal separation tank by the slurry pump. The centrifugal separator is a hydrocyclone with a conical structure. It has a sand discharge nozzle in its underflow outlet. The diameter of the sand discharge nozzle is variable. The underflow concentration is controlled by adjusting the diameter of the sand discharge nozzle so as to output high-concentration waste slurry.

4. The environmentally friendly full-scene drainage circulation system for concrete mixing plants according to claim 3, characterized in that, The gravity separator is a spiral chute gravity separator. After the high-concentration waste slurry output from the bottom of the centrifugal separator enters the gravity separator, it is separated according to the density difference between effective and ineffective particles. The effective particles include unhydrated cement particles and fine sand and gravel powder, and the ineffective particles include hydrated cement gel, clay impurities, and flocs. The density of the effective particles is greater than the density of the ineffective particles. The effective particles, due to their higher density, will move along the inner ring of the spiral chute in the gravity separator, while the ineffective particles, due to their lower density, will float on the surface of the water flow and be thrown towards the outer ring of the spiral chute.

5. The environmentally friendly full-scene drainage circulation system for concrete mixing plants according to claim 4, characterized in that, The density mixing unit includes a test tube located at the bottom of the homogenization tank. The test tube is equipped with a test pump and a three-way valve. One end of the three-way valve is connected to a weighing scale, and the other end flows back into the homogenization tank. The outlet of the test pump is equipped with a densitometer and a flow meter. The densitometer is used to measure the density of the water output from the bottom of the homogenization tank, and the flow meter is used to measure the flow rate in the test tube to control the frequency of the test pump and prevent the liquid flow rate in the test tube from being too slow, which would cause particle deposition and affect the degree. The density proportioning unit also includes a clean water supply valve, which is connected to the homogenization tank. The liquid density in the homogenization tank is controlled by adjusting the flow rate of the separated water containing effective particles and the clean water input into the homogenization tank.

6. The environmentally friendly full-scene drainage circulation system for a concrete mixing plant according to claim 5, characterized in that, After the liquid density in the homogenizing tank is adjusted to a constant value, it is output to the concrete mixer within a fixed density range. The slurry output from the homogenizing tank is used as the water required for concrete mixing. The effective particles in the slurry are directly used as raw materials for mixing, and the amount of raw materials input is reduced accordingly.

7. A control method for a full-scene drainage circulation system of an environmentally friendly concrete mixing plant as described in any one of claims 1-6, characterized in that, Includes the following steps: S100: Collect wastewater from the mixing plant, introduce it into the sand and gravel separator for pretreatment to separate large particles of sand and gravel, control the opening of the overflow chute or pipeline, connect the water to the high-frequency dewatering screen, start the high-pressure spray to wash the fine sand to improve the cleanliness, and then send it into the raw material warehouse. The mud and water are introduced into the intermediate buffer tank. S200: Add clean water to the intermediate buffer tank to dilute the mud and water, wash off impurity ions on the surface of the particles, start the slurry pump to pump the mud and water into the centrifugal separation tank, adjust the diameter of the sand discharge nozzle to control the underflow concentration and output high-concentration waste slurry, and filter the overflow containing impurities for use in mixing plant vehicle washing and site cleaning. S300: High-concentration waste slurry is introduced into a spiral chute gravity separator, which separates the effective and ineffective particles by utilizing the density difference between them. The effective particles move along the inner ring of the chute, while the ineffective particles float to the surface and are thrown to the outer ring, thus accurately achieving the classification and screening of the two types of particles. S400: Separated water containing effective particles is pumped into a homogenizing tank, while separated water containing ineffective particles is sent to a filter press for treatment. The sludge cake is transported off-site, and the filtrate is discharged or reused after meeting the standards. The pneumatic pulse array is activated to alternately spray air and stir in layers to prevent particle deposition, stratification, and crusting on the inner wall. S500: Open the density mixing unit, start the test pump and three-way valve, monitor the data through the density meter and flow meter, and adjust the pump frequency to avoid particle deposition. Adjust the clean water supply valve to control the inlet water flow and adjust the slurry concentration in the tank to the set range and keep it stable. S600, qualified slurry is fed into the concrete mixer, and the amount of raw materials input is reduced according to the effective particle content, so as to realize the closed-loop utilization and zero discharge of waste residue and wastewater.

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