A method and system for estimating the flow rate of water entering or exiting a pool tank

Abstract

The application provides a water tank water inflow and outflow flow estimation method, a liquid level meter is arranged in the water tank and is used for detecting a liquid level value of the water tank, and the method comprises the following steps: step A1, a first algorithm model is used to calculate water inflow and outflow of the water tank when a water inlet valve is in a closed time period; step A2, a second algorithm model is used to calculate water inflow and outflow of the water tank when the water inlet valve is in an open time period; wherein the first algorithm model and the second algorithm model are both established based on liquid level change of the water tank. The application proposes a soft flow meter control algorithm which does not need a flow meter hardware carrier and is not limited by site installation conditions, realizes water tank water inflow and outflow flow estimation based on existing hardware facilities of a pump room water tank, and reduces construction cost.

Description

Technical Field

[0001] This invention relates to the field of water conservancy equipment technology, and in particular to a method and system for estimating the flow rate of water entering and leaving a water tank or pool. Background Technology

[0002] In current secondary water supply systems using water tanks and variable frequency drives, flow meters are typically used to collect flow data from the inlet and outlet of the water tank. However, the construction of information systems for pump stations inevitably faces two dilemmas. First, current flow measurement relies primarily on hardware such as electromagnetic and ultrasonic flow meters, leading to increased construction costs due to the large investment in flow meter hardware. Second, many older pump stations have limited space, making on-site flow meter installation impossible. There is a gap in existing technology for water system-based algorithm design, using model calculations to replace hardware flow meters. This is partly because flow meter manufacturers need to ensure profitability and development through hardware sales from a commercial perspective, and partly because secondary water supply manufacturers often focus their expertise on hardware design, manufacturing, and processing, with relatively weak accumulation of technical expertise in algorithm models and industrial control systems. Summary of the Invention

[0003] Based on the problems existing in the prior art, the present invention provides a method for estimating the flow rate of water entering and leaving a water tank, aiming to solve the technical problems of high construction cost and difficulty in installing flow meters in some areas when using flow meters in the prior art.

[0004] A method for estimating the flow rate of water entering and leaving a water tank, comprising installing a level gauge in the tank to detect the water level, and including the following steps: Step A1: During the time period when the inlet valve is closed, the first algorithm model is used to calculate the inlet flow rate and outlet flow rate of the water tank; Step A2: During the time period when the inlet valve is open, the second method model is used to calculate the inlet flow rate and outlet flow rate of the water tank. Both the first and second algorithm models are based on the changes in the liquid level in the water tank.

[0005] Furthermore, in step A1, during the closed period of the water inlet valve, the first algorithm model sets the water inlet volume of the water tank to 0; The formula for the first algorithm model is shown below: ; in, Q 出 This refers to the water flow rate from the water tank. L 0 represents the water level in the tank at time t0 during the closed period of the inlet valve; L1 represents the water level in the tank at time t1 during the closed period of the inlet valve; S This is the bottom area of ​​the water tank; Δ t Let t1 be the time difference between time t1 and time t0, where time t1 is greater than time t0.

[0006] Furthermore, step A2 includes: Step A21: Obtain the opening time of the inlet valve; Step A22: Calculate the water flow rate of the water tank during the preset time period before the opening time of the inlet valve, so as to use it as the water flow rate of the water tank during the opening time period between the opening time and the closing time of the inlet valve. Step A23: During the opening period of the inlet valve, obtain the liquid level change value of the water tank, and calculate the inlet flow rate of the water tank during the opening period based on the liquid level change value and the outflow rate during the opening period.

[0007] Furthermore, in step A23, the formula for calculating the water flow rate of the water tank within the preset time period is as follows: ; in, Q 出 This refers to the water flow rate from the water tank. L 2 represents the water level in the tank at time t2, before the inlet valve opens; L 3 represents the water level in the tank at time t3, before the inlet valve opens; S This is the bottom area of ​​the water tank; Δ t 1 represents the time difference between time t3 and time t2, where time t3 is greater than time t2; Furthermore, in step A23, the formula for calculating the inflow rate of the water tank during the opening period is as follows: ; in, Q 入 This refers to the inflow rate of the water tank during the opening period; L 4 represents the water level in the tank at time t4 during the opening period of the inlet valve; L 5 represents the water level in the tank at time t5 during the opening period of the inlet valve; Δ t 2 represents the time difference between time t5 and time t4, where time t5 is greater than time t4.

[0008] Furthermore, t3 is the time 0-10 minutes before the inlet valve opens.

[0009] Furthermore, the activation periods are the morning peak hours, the midday peak hours, and the evening peak hours.

[0010] A system for estimating the flow rate of water entering and leaving a water tank, comprising the aforementioned method for estimating the flow rate of water entering and leaving a water tank, including: a level gauge for detecting the level value of the water tank; The inlet valve is installed on the inlet pipe; The processing module is connected to the level gauge and the inlet valve respectively. The processing module is configured with a first algorithm model and a second algorithm model for: Real-time acquisition of valve status and liquid level value of the inlet valve; The first algorithm model is used to calculate the inlet and outlet flow rates of the water tank during the period when the inlet valve is closed. The second algorithm model is used to calculate the inlet and outlet flow rates of the water tank during the opening period of the inlet valve; Both the first and second algorithm models are based on the changes in the liquid level in the water tank.

[0011] Furthermore, during the closed period of the inlet valve, the first algorithm model sets the water inlet volume of the water tank to 0; The formula for the first algorithm model is shown below: ; in, Q 出 This refers to the water flow rate from the water tank. L 0 represents the water level in the tank at time t0 during the closed period of the inlet valve; L 1 represents the water level in the tank at time t1 during the closed period of the inlet valve; S This is the bottom area of ​​the water tank; Δ t Let t1 be the time difference between time t1 and time t0, where time t1 is greater than time t0.

[0012] Furthermore, the processing module includes: The valve status acquisition module is used to acquire the opening time of the inlet valve; The first calculation module, connected to the valve status acquisition module, is used to calculate the water tank's outflow rate during a preset time period before the opening time of the inlet valve, so as to serve as the water tank's outflow rate during the opening time period between the opening and closing times of the inlet valve. The second calculation module is connected to the valve status acquisition module and the first calculation module respectively. It is used to acquire the liquid level change value of the water tank during the opening period of the inlet valve, and calculate the inlet flow rate of the water tank during the opening period based on the liquid level change value and the outlet flow rate during the opening period.

[0013] The beneficial technical effects of this invention are as follows: This invention proposes a hardware carrier that does not require a flow meter and a soft flow meter control algorithm that is not limited by on-site installation conditions. Based on the existing hardware facilities of the pump room, water tank, and water reservoir, it realizes the estimation of the inlet and outlet flow of the water tank. Attached Figure Description

[0014] Figure 1-2 This is a flowchart illustrating the steps of a method for estimating the flow rate of water entering and leaving a water tank in this invention. Figure 3 This is a schematic diagram of a system for estimating the flow rate of water entering and leaving a water tank according to the present invention. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0018] See Figure 1 This invention provides a method for estimating the flow rate of water entering and leaving a water tank, comprising the following steps: A level gauge is installed in the water tank to detect the water level value. Step A1: During the time period when the inlet valve is closed, the first algorithm model is used to calculate the inlet flow rate and outlet flow rate of the water tank; Step A2: During the time period when the inlet valve is open, the second method model is used to calculate the inlet flow rate and outlet flow rate of the water tank. Both the first and second algorithm models are based on the changes in the liquid level in the water tank.

[0019] This invention addresses the current state of hardware facilities in secondary water supply pump stations. Since equipment operation and water tank regulation and control are involved, all basic hardware facilities such as level gauges and electric valves are already in place. Therefore, this invention proposes a method for estimating inlet and outlet water flow without a flow meter, eliminating the need for significant additional costs associated with installing flow meters.

[0020] Because the water tank experiences simultaneous inflow and outflow during operation, it's necessary to decouple the inflow and outflow rates to obtain accurate data. While the outflow rate is intermittent and uncontrollable due to its correlation with user water usage, the inflow rate can be controlled by adjusting the inflow valve. Therefore, the water tank's operating states are categorized into two main types: when the inflow solenoid valve is closed, it operates in an "outflow-only" mode; and when the inflow valve is open, it operates in a "both inflow and outflow" mode.

[0021] Furthermore, in step A1, during the closed period of the water inlet valve, the first algorithm model sets the water inlet volume of the water tank to 0; The formula for the first algorithm model is shown below: ; in, Q 出 This refers to the water flow rate from the water tank. L 0 represents the water level in the tank at time t0 during the closed period of the inlet valve; L 1 represents the water level in the tank at time t1 during the closed period of the inlet valve; S This is the bottom area of ​​the water tank; Δ t Let t1 be the time difference between time t1 and time t0, where time t1 is greater than time t0.

[0022] When operating in "outflow only" mode, the inlet valve is closed, so the inflow rate is 0, and the liquid level change is directly related to the outflow rate.

[0023] Take Δ t The liquid level change over time, where the liquid level at time t0 is... L 0, experiencing Δ t After a certain time, the liquid level is L 1. The change in liquid level difference is Δ L ,at this time: ; Since the solenoid valve is closed at this time, Q 入 Substituting =0 into the above formula, we get: .

[0024] Because a solenoid valve is installed on top of the float valve, the adjustable liquid level range is relatively large. Before peak water usage, the water tank is at a high level. At this time, the equipment only discharges water and does not receive water, so the liquid level change Δ in the water tank is significant. L Multiply by the fixed base area S This is equivalent to the water supply volume, and its differential relationship with time is roughly equivalent to the water flow rate from the tank. Further, step A2 includes: Step A21: Obtain the opening time of the inlet valve; Step A22: Calculate the water flow rate of the water tank during the preset time period before the opening time of the inlet valve, so as to use it as the water flow rate of the water tank during the opening time period between the opening time and the closing time of the inlet valve. Step A23: During the opening period of the inlet valve, obtain the liquid level change value of the water tank, and calculate the inlet flow rate of the water tank during the opening period based on the liquid level change value and the outflow rate during the opening period.

[0025] During peak periods, the outflow rate fluctuates little, so step A22 can be used to estimate the outflow rate during periods of both inflow and outflow, and this can be used to calculate the flow rate. Collecting a large amount of inflow and outflow rate information facilitates peak-shaving and water storage. During off-peak periods before peak periods, the water tank is filled with water for a short time. During this short period, the outflow rate does not change much, and the inflow and outflow rates of the water tank can also be calculated using the methods in steps A21-A23.

[0026] Furthermore, in step A23, the formula for calculating the water flow rate of the water tank within the preset time period is as follows: ; in, Q 出 This refers to the water flow rate from the water tank. L 2 represents the water level in the tank at time t2, before the inlet valve opens; L 3 represents the water level in the tank at time t3, before the inlet valve opens; S This is the bottom area of ​​the water tank; Δ t 1 represents the time difference between time t3 and time t2, where time t3 is greater than time t2; Furthermore, in step A23, the formula for calculating the inflow rate of the water tank during the opening period is as follows: ; in, Q入 This refers to the inflow rate of the water tank during the opening period; L 4 represents the water level in the tank at time t4 during the opening period of the inlet valve; L 5 represents the water level in the tank at time t5 during the opening period of the inlet valve; Δ t 2 represents the time difference between time t5 and time t4, where time t5 is greater than time t4.

[0027] When operating in a "both in and out" state, in order to obtain the water tank outlet flow rate... Q 出 Under the same operating conditions (morning peak), the water level changes in the immediate time before the valve state switch are taken to calculate the water tank's outflow rate. Since the operating conditions are the same, the calculated outflow rate is roughly equivalent to the water tank's outflow rate during the simultaneous inflow and outflow process, i.e., the process when the inlet valve is open.

[0028] ; Record the water tank level at a certain moment before the valve is opened. L 2, after Δ t After 1 hour, the liquid level is now... L 3. The outflow rate is: ; Therefore, the formula for influent flow rate is: ; In other words, the peak liquid level change is the difference between the inlet flow rate and the outlet flow rate of the water tank. Therefore, to obtain the inlet flow rate of the water tank, the outlet flow rate under the same operating conditions can be calculated first. Since the operating conditions are the same, the outlet flow rate at a similar moment before valve opening is essentially equivalent to the outlet flow rate when water is simultaneously entering and exiting. After calculating the outlet flow rate, the coupled flow rate change of simultaneous water entry and exit can be obtained by differentiating the liquid level change * bottom area S (equivalent to volume) with time. This coupled flow rate is equal to the difference between the inlet and outlet flow rates. Combined with the outlet flow rate at a similar moment before valve opening, the inlet flow rate can then be calculated.

[0029] The gateway collects the transposed liquid level value. The gateway has built-in the first and second calculation models mentioned above. Since the gateway is a high-frequency acquisition device, the acquisition frequency can be set, and Δ is taken as the value. t 1=Δ t 2=Δ t Δ t With a very short time difference, the influent flow rate formula simplifies to: ; The purchase cost of a single DN100 electromagnetic flowmeter is around 10,000 yuan. For water companies managing hundreds or thousands of water tanks and pools, adding flowmeter hardware to each one would inevitably increase investment costs. By designing using the soft flow calculation method, the purchase cost of flowmeters can be reduced by millions of yuan. At the same time, there are no on-site installation, maintenance and replacement costs for hardware, resulting in good economic benefits.

[0030] Social Benefits: With the advancement of smart water management informatization and energy conservation, energy consumption measurement indicators based on power consumption per thousand tons of water per hundred-meter head require the acquisition of equipment energy consumption and flow data. Soft flow meters can better accelerate the informatization process of smart water management and provide a better understanding of equipment energy consumption evaluation.

[0031] Furthermore, t3 is the time 0-10 minutes before the inlet valve opens.

[0032] Furthermore, the activation periods are the morning peak hours, the midday peak hours, and the evening peak hours.

[0033] Furthermore, the inlet valve is a solenoid valve.

[0034] The present invention also provides a flow rate estimation system for water tanks and reservoirs, including the above-mentioned method for estimating the flow rate of water tanks and reservoirs, comprising: a level gauge (1) for detecting the level value of the water tank; Water inlet valve (2) is installed on the water inlet pipe; The processing module (3) is connected to the level gauge (1) and the inlet valve (2) respectively. The processing module (3) sets up a first algorithm model and a second algorithm model for: Real-time acquisition of valve status and liquid level of inlet valve (2); The first algorithm model is used to calculate the inlet and outlet flow rates of the water tank during the period when the inlet valve is closed. The second algorithm model is used to calculate the inlet and outlet flow rates of the water tank during the opening period of the inlet valve; Both the first and second algorithm models are based on the changes in the liquid level in the water tank.

[0035] Furthermore, during the closed period of the inlet valve, the first algorithm model sets the water inlet volume of the water tank to 0; The formula for the first algorithm model is shown below: ; in, Q 出 This refers to the water flow rate from the water tank. L 0 represents the water level in the tank at time t0 during the closed period of the inlet valve; L 1 represents the water level in the tank at time t1 during the closed period of the inlet valve; S This is the bottom area of ​​the water tank; Δ t Let t1 be the time difference between time t1 and time t0, where time t1 is greater than time t0.

[0036] Furthermore, the processing module (3) includes: a valve status acquisition module (31), used to acquire the opening time of the inlet valve; The first calculation module (32) is connected to the valve status acquisition module (31) and is used to calculate the water flow rate of the water tank during a preset time period before the opening time of the inlet valve, so as to serve as the water flow rate of the water tank during the opening time period between the opening time and the closing time of the inlet valve. The second calculation module (33) is connected to the valve status acquisition module (31) and the first calculation module (32) respectively. It is used to acquire the liquid level change value of the water tank during the opening time period of the inlet valve, and calculate the inlet flow rate of the water tank during the opening time period based on the liquid level change value and the outlet flow rate during the opening time period.

[0037] The processing module (3) is the gateway.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for estimating the flow rate of water entering and leaving a water tank or pool, characterized in that, The flow estimation method is based on the hardware facilities of the secondary water supply pump station; Installing a level gauge in the water tank to detect the water level includes the following steps: Step A1: During the time period when the inlet valve is closed, the first algorithm model is used to calculate the inlet flow rate and outlet flow rate of the water tank; Step A2: During the time period when the inlet valve is open, the second algorithm model is used to calculate the inlet flow rate and outlet flow rate of the water tank; Both the first algorithm model and the second algorithm model are established based on the liquid level changes in the water tank; Step A2 includes: Step A21: Obtain the opening time of the water inlet valve; Step A22: Calculate the water flow rate of the water tank during a preset time period before the opening time of the inlet valve, so as to use the water flow rate of the water tank during the opening time period between the opening time and the closing time of the inlet valve. Step A23: During the opening time period of the inlet valve, obtain the liquid level change value of the water tank, and calculate the inlet flow rate of the water tank during the opening time period based on the liquid level change value and the outflow rate during the opening time period.

2. The method for estimating the flow rate of water entering and leaving a water tank as described in claim 1, characterized in that, In step A1, during the closed time period, the first algorithm model sets the water inlet volume of the water tank to 0. The formula for the first algorithm model is shown below: ； in, Q 出 This refers to the water flow rate from the water tank. L 0 represents the water level in the tank at time t0 during the closed period of the inlet valve; L 1 represents the water level in the tank at time t1 during the closed period of the inlet valve; S The bottom area of ​​the water tank; Δ t Let t1 be the time difference between time t1 and time t0, where time t1 is greater than time t0.

3. The method for estimating the flow rate of water entering and leaving a water tank as described in claim 1, characterized in that, In step A22, the formula for calculating the water flow rate of the water tank within the preset time period is as follows: ； in, Q 出 This refers to the water flow rate from the water tank. L 2 represents the water level in the tank at time t2, prior to the opening of the inlet valve; L 3 represents the water level in the tank at time t3, prior to the opening of the inlet valve; S The bottom area of ​​the water tank; Δ t 1 represents the time difference between time t3 and time t2, where time t3 is greater than time t2.

4. The method for estimating the flow rate of water entering and leaving a water tank as described in claim 3, characterized in that, In step A23, the formula for calculating the inflow rate of the water tank during the opening time period is as follows: ； in, Q 入 This refers to the inflow rate of the water tank during the opening period; L 4 represents the water level value of the tank at time t4 during the opening period of the inlet valve; L 5 represents the water level in the tank at time t5 during the opening period of the inlet valve; Δ t 2 represents the time difference between time t5 and time t4, where time t5 is greater than time t4.

5. The method for estimating the flow rate of water entering and leaving a water tank as described in claim 3, characterized in that, in, t3 is the time 0 to 10 minutes before the opening of the inlet valve.

6. The method for estimating the flow rate of water entering and leaving a water tank as described in claim 1, characterized in that, The opening time periods are the morning peak period, the middle peak period, and the evening peak period.

7. A system for estimating the flow rate of water entering and leaving a water tank or pool, characterized in that, The method for estimating the flow rate of water entering and leaving a water tank as described in any one of claims 1-6 includes: A level gauge is used to detect the liquid level in the water tank. The inlet valve is installed on the inlet pipe; The processing module is connected to the level gauge and the inlet valve respectively. The processing module is configured with a first algorithm model and a second algorithm model, used for: The valve status of the inlet valve and the liquid level value are collected in real time. The first algorithm model is used to calculate the inlet flow rate and outlet flow rate of the water tank during the closed period of the inlet valve; The second algorithm model is used to calculate the inlet flow rate and outlet flow rate of the water tank during the opening period of the inlet valve; Both the first algorithm model and the second algorithm model are established based on the liquid level changes in the water tank.

8. The flow rate estimation system for inlet and outlet water of a water tank as described in claim 7, characterized in that, The processing module includes: The valve status acquisition module is used to acquire the opening time of the inlet valve; The first calculation module, connected to the valve status acquisition module, is used to calculate the water flow rate of the water tank during a preset time period before the opening time of the inlet valve, so as to use the water flow rate of the water tank during the opening time period between the opening time and the closing time of the inlet valve. The second calculation module is connected to the valve status acquisition module and the first calculation module, respectively. It is used to acquire the liquid level change value of the water tank during the opening time period of the inlet valve, and calculate the inlet flow rate of the water tank during the opening time period based on the liquid level change value and the outflow rate during the opening time period.

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