Sewage sampling and blending method, blending device and concrete mixing plant

Abstract

The invention relates to a sewage sampling method, a sewage blending method, a sewage blending device and a concrete mixing plant, the sewage sampling method comprises the following steps: setting a water scale, and carrying out cleaning, feeding, overflow stable weighing, discharging and cleaning operations to realize sewage sampling and calculate accurate sewage sampling concentration; according to the blending method, the sewage sampling method is adopted to sample sewage in the sewage tank and the blending tank to calculate the sewage concentration, the sewage filling time and the clear water filling time are calculated according to the target sewage concentration, and the purpose of accurately and automatically blending the required sewage concentration is achieved. The blending device is provided with a water scale and adopts the blending method to obtain sewage with stable concentration; the concrete mixing plant is provided with the blending device, so that the concentration of sewage for production is kept stable and reliable for a long time. The problem that the sewage blending concentration of the blending tank is unstable is fundamentally solved, and the production requirement of a concrete mixing plant is met.

Description

Technical Field

[0001] The invention relates to a sewage sampling and mixing method, a mixing device and a concrete mixing station, and belongs to the technical field of concrete mixing station production. Background Art

[0002] A concrete mixing station is a device that measures sand, gravel, cement, fly ash, water or sewage, liquid admixtures, etc. according to a certain ratio, and then puts them into a mixer to mix them into qualified concrete. At present, the sewage mixing device of a concrete mixing station includes a sewage tank, a clean water tank and a mixing tank. Figure 1 The sewage tank is used to store the car washing sewage in the factory area, and the clean water tank is used to store clean water. The sewage in the sewage tank and the clean water in the clean water tank are pumped into the mixing tank. After the sewage and clean water are mixed, they are pumped to the mixing station to participate in the concrete mixing production.

[0003] When the blending tank is used for the first time, the sewage concentration is manually tested, and then the sewage valve and clean water valve openings are manually adjusted. The amount of sewage added and the amount of clean water added cannot be accurately controlled. Therefore, the sewage concentration prepared for the first use is difficult to meet the customer's requirements. During the production process, as the sewage concentration entering the sewage tank changes, the concentration of the sewage tank also changes, and it is impossible to measure in time. At the same time, the sewage feed valve and the clean water feed valve cannot be adjusted in time. Therefore, during the production process, the deviation between the sewage concentration value of the blending tank and the expected concentration value will become larger and larger.

[0004] In view of the existing problems of sewage allocation in concrete mixing plants, an improvement plan has been adopted: the sewage tank concentration and the allocation tank concentration are detected by sewage detectors to guide the adjustment of the regulating valves. A sewage concentration monitor is installed in the allocation tank and sewage tank respectively to monitor the real-time sewage concentration. According to the real-time sewage concentration value, the workers are guided to adjust the opening of the water inlet valve. See Figure 2 However, during the first use and subsequent use of the blending tank, after detecting the concentration of sewage in the sewage tank and the blending tank, the valve opening cannot be automatically adjusted, so the concentration expected by the customer cannot be accurately blended; in addition, since the sewage contains a certain amount of mud, after a period of use, the surface of the sewage detector is prone to adhesion of mud, which will seriously affect the reliability of concentration detection and may even cause detection failure.

[0005] Therefore, there is an urgent need for a detection method that can stably detect sewage concentration over a long period of time, as well as a mixing method and mixing device that can accurately adjust sewage concentration to meet the production requirements of maintaining a stable sewage concentration in concrete mixing plants. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a method and device for detecting the sewage concentration in a sewage tank and a mixing tank, an algorithm for sewage concentration, and a method for calculating the mixing time of sewage and clean water, which are used to solve the problem of unstable sewage mixing concentration in the mixing tank and meet the actual production requirements of a concrete mixing station.

[0007] The object of the present invention is achieved in that: A method for sampling sewage, providing a water scale with a fixed volume V for weighing the weight of liquid with a volume V, comprising the following steps: Step S1, injecting a volume V of clean water into the water scale, and weighing the weight M of the clean water; Step S2, emptying the water scale and cleaning the water scale; Step S3: inject a volume V of wastewater to be sampled into the water scale, and weigh the weight M of the wastewater. n ; Step S4, emptying the water scale and cleaning the water scale; Step S5: Calculate the sewage sampling concentration m n , according to the formula: m n =(M n -M) / M, calculate the sewage sampling concentration m n .

[0008] Furthermore, an overflow port is provided on the top of the water scale for overflow of sewage or clean water, thereby ensuring that the volume of the sampled sewage or clean water is V.

[0009] Furthermore, in step S1, when the water scale is filled with clean water and overflow occurs, the injection of clean water is stopped, and the clean water weight M is read after the overflow ends and the weighing data of the water scale is stable.

[0010] Furthermore, in step S3, when the sewage fills the water scale and overflows, the sewage injection is stopped, and the sewage weight M is read after the overflow ends and the weighing data of the water scale is stable. n .

[0011] A sewage preparation method is implemented based on any of the sewage sampling methods, comprising the following steps: Step S10, collecting sewage from the sewage tank and the blending tank, and injecting them into the water scale respectively; Step S20, weighing the weights M1 and M2 of the collected sewage in the sewage tank and the blending tank at the same volume V with a water scale; Step S30, calculating the sewage sampling concentrations m1 and m2 of the collected sewage tank and the blending tank; Step S40: when the liquid level of the blending tank is lower than the blending lower limit, start the blending; Step S50, execute blending: inject the sewage in the sewage tank and the clean water in the clean water tank into the blending tank respectively, and control the sewage injection time t5 and the clean water injection time t6. The calculation formulas of t5 and t6 are as follows:

[0012]

[0013] Among them, V2 is the target volume of the mixed sewage in the mixing tank; V1 is the existing volume of sewage in the mixing tank before mixing; m is the sewage concentration in the mixing tank expected by the customer; m1 is the sewage sampling concentration of the sewage tank before mixing; m2 is the sewage sampling concentration of the mixing tank before mixing; q1 is the flow rate of sewage from the sewage tank injected into the mixing tank; q2 is the flow rate of clean water from the clean water tank injected into the mixing tank; Step S60: When the liquid level in the blending tank reaches the upper limit of the blending, or when the sewage and clean water are injected, the blending is completed.

[0014] Furthermore, the steps S10 to S30 are executed in a timed loop to ensure that the sewage sampling concentrations m1 and m2 in the sewage tank and the blending tank are the latest data.

[0015] Furthermore, the mixing tank is a cylinder with an inner diameter of d, a lower limit of the liquid level height of h1, and a higher limit of the liquid level height of h2.

[0016] A sewage mixing device comprises a sewage tank, a mixing tank and a clean water tank, and a water scale with a fixed volume V; an overflow port is provided on the top of the water scale; the sewage tank, the mixing tank and the clean water tank are connected to the water scale through independent valves and pipelines, and sewage or clean water in corresponding tanks are respectively injected into the water scale; the sewage mixing device adopts any of the sewage mixing methods to perform sewage mixing operations.

[0017] Furthermore, the sewage tank and the clean water tank are connected to the mixing tank through independent pumps and pipelines, and sewage and clean water are respectively injected into the mixing tank to realize the mixing operation.

[0018] A concrete mixing station is provided, which is equipped with any of the above-mentioned sewage mixing devices to provide mixed sewage for concrete mixing production.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The sewage sampling method of the present invention weighs the sewage to be sampled by setting a water scale and calculates the sewage sampling concentration by a sewage concentration algorithm. No sewage concentration monitor is required during sampling, and there is no detection reliability problem, so long-term stable and effective detection can be guaranteed. The sewage blending method of the present invention adopts the sewage sampling method to complete the sampling of sewage in the sewage tank or the blending tank and calculate the corresponding sewage sampling concentration, and then calculates the flow rate of sewage and clean water pumped into the blending tank from the sewage tank and the clean water tank, calculates the sewage filling time and the clean water filling time under the target sewage concentration, and realizes accurate blending of the sewage concentration in the blending tank by controlling the sewage filling time and the clean water filling time, thereby solving the problem of unstable sewage concentration in the blending tank; The sewage mixing device of the present invention is based on the original sewage mixing device, and a water scale is added to weigh and sample the sewage and calculate the sampling concentration, and the sewage mixing method is used to achieve the purpose of stabilizing the concentration of the sewage. The concrete mixing station of the present invention is equipped with the sewage mixing device, so that the concentration of the mixed sewage can be kept stable and reliable for a long time, thus meeting actual production needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural diagram of the sewage distribution device of the original concrete mixing station.

[0021] Figure 2 The present invention is a schematic diagram of the structure of a sewage blending device for a concrete mixing station in the prior art.

[0022] Figure 3 The present invention is a flowchart of a sewage sampling method.

[0023] Figure 4 The present invention is a schematic structural diagram of a sewage mixing device. DETAILED DESCRIPTION

[0024] The following are parameter descriptions of the embodiments: d: Diameter of the leveling tank (the leveling tank is a cylinder), unit: meter Material level: used to measure the real-time height of sewage in the mixing tank h1: The lower limit height of the mixing tank for mixing, unit: meter h2: the expected height of the mixing tank, unit: meter q1: Flow rate of sewage pump, in liters per second: L / S q2: Flow rate of the clean water pump, in liters per second: L / S V: The volume of the water scale, in L V1: The volume of sewage in the mixing tank, unit: cubic meter V2: target volume of the mixing tank, corresponding to the mixing liquid level h2, unit: cubic meter M: weight of clean water with volume V, in kg M1: Sampling weight of sewage tank M2: Sampling weight of the blending tank m1: Sampling concentration of sewage tank m2: sampling concentration of the mixing tank m: The concentration of the blending tank expected by the customer t1: cleaning time of water scale, unit: second t2: water scale feeding time, unit: second t3: water scale stabilization time, unit: second t4: discharge time of water scale, unit: second t5: The system calculates the time it takes for the sewage tank to add sewage to the blending tank, unit: seconds t6: The system calculates the time it takes for the clean water tank to add clean water to the mixing tank, unit: seconds Example

[0025] See also Figure 2 The present invention relates to a sewage sampling method, which comprises the following steps: firstly setting a water scale with a fixed volume V to weigh the weight of a liquid with a volume V; setting an overflow port on the top of the water scale to overflow sewage or clean water to ensure that the volume of the sampled sewage or clean water is V unchanged; and Step S1, injecting clean water of volume V into the water scale, and weighing the weight M of the clean water; when the clean water fills the water scale and overflows, stop injecting clean water, wait until the overflow ends and the weighing data of the water scale is stable, the water scale is stable for a time t3, and the weight M of the clean water is read; Step S2, empty the water scale, clean the water scale, and let the water flow out of the water scale through the discharge valve, the cleaning time is t1; Step S3: inject a volume V of wastewater to be sampled into the water scale, and weigh the weight M of the wastewater. n When the sewage fills the water scale and overflow occurs, stop injecting sewage. After the overflow ends and the weighing data of the water scale stabilizes, the water scale stabilizes for a time t3 and reads the sewage weight M. n ; After the cleaning stage, the feeding stage begins. The sewage valve is opened or the water inlet valve is adjusted, and the sewage enters the water scale. The feeding time is t2. The feeding time should ensure that the sewage in the water scale is in an overflow state to ensure the sampling amount. After the sampling is completed, it is necessary to wait for the excess sewage in the water scale to completely overflow, and then the stabilization time t3 is read, and then the sewage weight M1 or M2 is read. Step S4, after sampling is completed, open the discharge valve below the water scale to completely discharge the sewage in the water scale, and the discharge time is t4; after the water scale is emptied, clean the water scale and let the water flow out of the water scale through the discharge valve, and the cleaning time is t1; Step S5: Calculate the sewage sampling concentration m n , according to the formula: m n =(M n-M) / M, calculate the sewage sampling concentration m n .

[0026] The sewage sampling method of the present invention is used to sample the sewage in the sewage tank or the mixing tank and calculate the sewage sampling concentrations m1 and m2 of the sewage in the sewage tank or the mixing tank. The specific operation is as follows: After sampling begins, the water scale is first cleaned with clean water, and the cleaning time is t1; after the cleaning stage, the feeding stage begins, and the sewage in the sewage tank or the mixing tank is injected into the water scale, and the feeding time is t2. The feeding time should be able to ensure that the sewage in the water scale is in an overflowing state to ensure the sampling volume; after sampling, it is necessary to wait for the excess sewage in the water scale to completely overflow, and then wait for the stabilization time t3, and then read the sewage weight M1 or M2 at this time; after sampling, the sewage in the water scale is completely discharged, and the discharge time is t4; after the water scale is cleaned with clean water, sampling is completed; Then, according to the sample weight M1\M2 and the standard weight M of clean water on the water scale, we can calculate: Sampling concentration of sewage tank m1=(M1-M) / M Sampling concentration of the mixing tank m2 = (M2-M) / M At this point, the sampling of sewage in the sewage tank or the blending tank is completed and the corresponding sewage sampling concentration is obtained. No sewage concentration monitor is required during the sampling period, and there is no problem with detection reliability, so long-term stable and effective detection can be guaranteed. Example

[0027] The present invention relates to a sewage preparation method, which is implemented based on the sewage sampling method in Example 1, and comprises the following steps: Step S10, collecting sewage from the sewage tank and the blending tank, and injecting them into the water scale respectively; Step S20, weighing the weights M1 and M2 of the collected sewage in the sewage tank and the blending tank at the same volume V with a water scale; Step S30, calculating the sewage sampling concentrations m1 and m2 of the collected sewage tank and the blending tank; Since the concentration of car wash wastewater in the concrete mixing plant is unstable, the concentration of wastewater in the wastewater tank for collecting car wash wastewater is also constantly changing; and the concentration of existing wastewater in the blending tank will directly affect the concentration of the final blended wastewater. Therefore, the above steps S10 to S30 are executed in a timed loop to ensure that the wastewater sampling concentrations m1 and m2 of the wastewater tank and the blending tank are the latest data; Step S40: when the liquid level of the blending tank is lower than the blending lower limit, start the blending; Step S50, execution deployment: First perform the allocation calculation: I. Concentration weight after preparation = concentration weight before preparation + concentration weight of sewage feed Substituting the variables we get:

[0028] It can be concluded that the sewage filling time is: ...(Formula 1) II. Weight after mixing = weight before mixing + sewage inflow + clean water inflow =

[0029] From this, the time for adding clean water can be obtained: ...(Formula 2) In the above formulas, V2 is the target volume of the mixed sewage in the mixing tank; V1 is the existing volume of the sewage in the mixing tank before mixing; m is the sewage concentration in the mixing tank expected by the customer; m1 is the sewage sampling concentration of the sewage tank before mixing; m2 is the sewage sampling concentration of the mixing tank before mixing; q1 is the flow rate of sewage from the sewage tank injected into the mixing tank; q2 is the flow rate of clean water from the clean water tank injected into the mixing tank; For the convenience of calculation, in this embodiment, the mixing tank is set as a cylinder with an inner diameter of d, the liquid level of the lower limit of mixing is h1, and the liquid level of the upper limit of mixing is h2. Target volume of wastewater in the mixing tank

[0030] Existing volume of sewage in the mixing tank before mixing

[0031] Substituting the volume formula into Equation 1 and Equation 2 yields:

[0032]

[0033] The sewage injection time t5 and the clean water injection time t6 are calculated by the above formulas, and then the sewage in the sewage tank and the clean water in the clean water tank are respectively injected into the blending tank according to the calculated injection times t5 and t6 for sewage blending; In other embodiments, the shape of the blending tank may be a cuboid, a cube or other shapes. It is only necessary to calculate its volume, and the sewage sampling method and sewage blending method of the present invention are also applicable, that is, the present invention is not limited by the shape of the container; When the liquid level in the blending tank is lower than the blending lower limit h1, the system starts blending. It only needs to calculate the time t5 for the sewage tank to add sewage to the blending tank and the time t6 for the clean water tank to add clean water to the blending tank based on the customer's desired target sewage concentration m, sewage injection flow q1 and clean water injection flow q2, thereby achieving the purpose of controlling the target sewage concentration in the blending tank. When h1=0, it corresponds to the first deployment, and the above algorithm is also applicable. Therefore, this algorithm is also applicable to the first deployment condition; Step S60, when the liquid level in the blending tank reaches the upper limit of the blending, or when both the sewage and the clean water are injected, the blending is completed; in this embodiment, when the liquid level in the blending tank is adjusted to a height h2, or when both the sewage and the clean water are injected, the blending is completed.

[0034] In other embodiments, multiple sewage tanks may be provided. It is only necessary to adopt the sewage blending method of the present invention to sample each sewage tank and calculate the sewage sampling concentration, and then allocate the proportion of each sewage tank to participate in the blending, and then calculate and control the time for each sewage tank to inject sewage, so as to complete the sewage blending; The sewage blending method of the present invention first adopts the sampling method in Example 1 to sample the sewage in the sewage tank and the blending tank respectively, and calculates the latest sewage concentrations in the sewage tank and the blending tank, thereby avoiding the adverse effects of the constantly changing sewage concentration on the blending; then, according to the customer's expected sewage target concentration in the blending tank, combined with the latest sewage concentrations in the sewage tank and the blending tank obtained by sampling, as well as the flow rates of sewage and clean water injected into the blending tank by the sewage tank and the clean water tank, respectively, the sewage injection time and the clean water injection time are calculated, thereby achieving the purpose of the blending tank to blend sewage according to customer needs and ensuring the stability of the sewage concentration in the blending tank. Example

[0035] See also Figure 3 The present invention relates to a sewage blending device, comprising a sewage tank, a blending tank, a clean water tank, and a water scale with a fixed volume V; the sewage tank and the clean water tank are connected to the blending tank through independent pumps and pipelines, and sewage and clean water are respectively injected into the blending tank to realize the blending operation; an overflow port is provided at the top of the water scale; the sewage tank, the blending tank and the clean water tank are connected to the water scale through independent valves and pipelines, and sewage or clean water in the corresponding tanks are respectively injected into the water scale; the sewage blending device adopts the sewage blending method in the embodiment 2, and calculates and controls the sewage injection time of the sewage tank injecting sewage into the blending tank and the clean water injection time of the clean water tank injecting clean water into the blending tank, respectively, to realize the sewage blending operation and ensure that the sewage concentration in the blending tank meets the production requirements of customers. Example

[0036] The present invention relates to a concrete mixing station, which is equipped with the sewage blending device of the third embodiment to provide blended sewage for concrete mixing production. The concentration of the sewage is no longer affected by the concentration change of the car wash sewage. The sewage concentration can be kept stable for a long time, thus meeting the needs of concrete mixing production.

[0037] In addition: It should be noted that the above specific implementation is only an optimization scheme of this patent. Any changes or improvements made by technicians in this field based on the above concept are within the scope of protection of this patent.

Claims

1. A sewage sampling method, characterized in that: Setting up a water scale with a fixed volume V to weigh the volume V of liquid comprises the following steps: Step S1, injecting a volume V of clean water into the water scale, and weighing the weight M of the clean water; Step S2, emptying the water scale and cleaning the water scale; Step S3: inject a volume V of wastewater to be sampled into the water scale, and weigh the weight M of the wastewater. n ; Step S4, emptying the water scale and cleaning the water scale; Step S5: Calculate the sewage sampling concentration m n , according to the formula: m n =(M n -M) / M, calculate the sewage sampling concentration m n .

2. The sewage sampling method according to claim 1, characterized in that: An overflow port is arranged on the top of the water scale for overflow of sewage or clean water, so as to ensure that the volume of the sampled sewage or clean water is V.

3. The sewage sampling method according to claim 2, characterized in that: In step S1, when the water scale is filled with clean water and overflow occurs, the injection of clean water is stopped, and the clean water weight M is read after the overflow ends and the weighing data of the water scale is stable.

4. The sewage sampling method according to claim 2, characterized in that: In step S3, when the sewage fills the water scale and overflows, stop injecting sewage. After the overflow ends and the weighing data of the water scale stabilizes, read the sewage weight M. n .

5. A sewage preparation method, characterized in that: The method is implemented based on any one of the sewage sampling methods in claims 1 to 4, and comprises the following steps: Step S10, collecting sewage from the sewage tank and the blending tank, and injecting them into the water scale respectively; Step S20, weighing the weights M1 and M2 of the collected sewage in the sewage tank and the blending tank at the same volume V with a water scale; Step S30, calculating the sewage sampling concentrations m1 and m2 of the collected sewage tank and the blending tank; Step S40: when the liquid level of the blending tank is lower than the blending lower limit, start the blending; Step S50, execute blending: inject the sewage in the sewage tank and the clean water in the clean water tank into the blending tank respectively, and control the sewage injection time t5 and the clean water injection time t6. The calculation formulas of t5 and t6 are as follows: ； ； Among them, V2 is the target volume of the mixed sewage in the mixing tank; V1 is the existing volume of sewage in the mixing tank before mixing; m is the sewage concentration in the mixing tank expected by the customer; m1 is the sewage sampling concentration of the sewage tank before mixing; m2 is the sewage sampling concentration of the mixing tank before mixing; q1 is the flow rate of sewage from the sewage tank injected into the mixing tank; q2 is the flow rate of clean water from the clean water tank injected into the mixing tank; Step S60: When the liquid level in the blending tank reaches the upper limit of the blending, or when the sewage and clean water are injected, the blending is completed.

6. The sewage preparation method according to claim 5, characterized in that: The steps S10 to S30 are executed in a timed loop to ensure that the sewage sampling concentrations m1 and m2 in the sewage tank and the blending tank are the latest data.

7. The sewage preparation method according to claim 5, characterized in that: The mixing tank is a cylinder with an inner diameter of d. The liquid level height at the lower limit of mixing is h1, and the liquid level height at the upper limit of mixing is h2.

8. A sewage blending device, comprising a sewage tank, a blending tank and a clean water tank, characterized in that: It also includes a water scale with a fixed volume V; an overflow port is provided at the top of the water scale; the sewage tank, the mixing tank and the clean water tank are connected to the water scale through independent valves and pipelines, and the sewage or clean water in the corresponding tanks are respectively injected into the water scale; the sewage mixing device adopts any one of the sewage mixing methods in claims 5 to 7 to perform sewage mixing operations.

9. The sewage preparation device according to claim 8, characterized in that: The sewage tank and the clean water tank are connected to the mixing tank through independent pumps and pipelines, and sewage and clean water are respectively injected into the mixing tank to realize the mixing operation.

10. A concrete mixing station, characterized in that: Install any one of the sewage blending devices in claim 8 or 9 to provide blended sewage for concrete mixing production.

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