Flow measurement system and flow control method

Abstract

The application discloses a flow measurement system and a flow control method, which comprise a liquid inlet pipe, a liquid outlet pipe and a dosing pipe group, the dosing pipe group is provided with an input end and an output end at two ends respectively, the input end is connected with the liquid inlet pipe, and the output end is connected with the liquid outlet pipe, a dosing pump is arranged at the middle section of the dosing pipe group, the dosing pump is used for pumping reagents from the input end to the output end and can be metered, a flowmeter is arranged on the liquid outlet pipe, the dosing pipe group is provided with two groups, and the two groups of dosing pipe groups are arranged in parallel, a buffer pipe is further arranged, one end of the buffer pipe is connected with the output end of the dosing pipe group, and the other end of the buffer pipe is provided with a diaphragm damper. The diaphragm damper can be used for buffering through pressure, so that the dosing output can be more stable, and the dosing amount can be accurately controlled.

Description

Technical Field

[0001] This invention relates to flow control equipment, and more specifically, to a flow measurement system, and also to a flow control method using the flow measurement system. Background Technology

[0002] In some wastewater treatment projects, it is necessary to add certain chemicals (such as acidic, alkaline, or corrosive chemicals) to the wastewater treatment system. Pumping devices are typically used to deliver these chemicals, ensuring timely and precise dosage. In other projects, precise chemical dosing is required, with small dosages and the need for long-term, stable dosing.

[0003] Current dosing equipment typically uses metering pumps for chemical dosing, which can achieve normal dosing. However, metering pumps have a certain degree of accuracy error. When the dosage is small, the error caused by the metering pump's inaccuracy is relatively large. Especially for chemicals that require long-term dosing, small deviations each time accumulate, leading to a continuous increase in error, making accurate measurement difficult. Over time, this can easily affect the normal operation of wastewater treatment projects.

[0004] Therefore, a new solution is needed to address this problem. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a flow measurement system and a flow control method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A flow measurement system includes an inlet pipe, an outlet pipe, and a dosing pipe assembly. The dosing pipe assembly has an input end and an output end at both ends. The input end is connected to the inlet pipe, and the output end is connected to the outlet pipe. A dosing pump is installed in the middle section of the dosing pipe assembly. The dosing pump is used to pump reagent from the input end to the output end and is capable of metering. A flow meter is installed in the outlet pipe. Two sets of dosing pipe assemblies are provided, connected in parallel. The system also includes a buffer pipe, one end of which is connected to the output end of the dosing pipe assembly, and the other end is equipped with a diaphragm damper.

[0008] The present invention is further configured such that the output ends of the two sets of dosing tubes are connected by a connecting pipe, and the buffer tube is connected to the output end of the dosing tube set by the connecting pipe.

[0009] The present invention is further configured to include a pressure gauge, which is used to detect the pressure at the output end of the dosing tubing assembly.

[0010] The invention is further configured to include a safety valve having a first port and a second port. The first port is connected to the input end of the dosing assembly, and the second port is connected to the output end of the dosing assembly. The safety valve is capable of releasing pressure from the second port to the first port.

[0011] The present invention also provides a flow control method, which uses the flow measurement system described above, wherein the amount pumped by the two sets of dosing pumps each time is a1 and a2, respectively; within a unit time t, the system presets the dosing amount as a, where a1 < a < a2;

[0012] i represents the number of pumping operations over time interval t, where i = i + 1; n represents the number of pumping operations of the first group of dosing pumps, where n = n + 1 for each pumping operation; m represents the number of pumping operations of the second group of dosing pumps, where m = m + 1 for each pumping operation; and at each time interval t, one of the two groups of dosing pumps is selected to pump once, where i = n + m.

[0013] The present invention is further configured such that the flow control method includes the following steps: two sets of dosing pumps alternately perform pumping, and at each time interval t, the flow meter detects the flow rate and records the actual total flow rate as V'(i); the current system preset total flow rate is V(i), V(i) = a·i;

[0014] By comparing the magnitudes of V'(i) and V(i), and then calculating the deviation between V'(i) and V(i), the percentage deviation rate K is calculated, K=|V'(i)-V(i)| / V(i). The deviation rate K represents the deviation between the actual reagent supply and the pre-approved standard quantity.

[0015] When V'(i) is greater than V(i) and the deviation rate K exceeds the preset deviation rate Q1, the first group of dosing pumps will be selected for pumping next time.

[0016] When V'(i) is less than V(i) and the deviation rate K exceeds the preset deviation rate Q1, the second group of dosing pumps will be selected for pumping next time.

[0017] The present invention is further configured such that the deviation rates of a1 and a2 from a do not exceed the preset deviation rate Q2.

[0018] The present invention is further configured such that the preset deviation rate Q1 is less than the preset deviation rate Q2; the preset deviation rate Q2 is 3.0%-5.0%, and the preset deviation rate Q1 is 0.5%-1.0%.

[0019] The invention is further configured such that, after each pumping operation, the corresponding pumping volumes a1 and a2 of the two sets of dosing pumps are reset.

[0020] When the first group of dosing pumps starts pumping, the flow meter displays the actual total flow rate as V'(i). Here, the actual pumping amount a1 = V'(i) - V'(i-1) is pumped. The pumping amount a1 of the first group of dosing pumps is recorded again.

[0021] When the second set of dosing pumps starts pumping, the flow meter displays the actual total flow rate as V'(i). The actual pumping amount a1 = V'(i) - V'(i-1) is then recorded again. The pumping amount a2 of the second set of dosing pumps is then recorded again.

[0022] The present invention is further configured such that, during the pumping process, the pressure P1 at the output end of the dosing pipe group is detected by pressure gauge one, and the internal pressure P2 of the diaphragm damper is detected by pressure gauge two, wherein 0.5P2 < P1 < 0.75P2.

[0023] In summary, the present invention has the following beneficial effects:

[0024] By setting up a diaphragm damper, pressure can be buffered, making the system output flow smoother. When the dosing pump pumps, the pressure at the output end will increase significantly. At this time, some of the agent can be buffered and enter the diaphragm damper. Then, the diaphragm damper releases slowly under the action of pressure, keeping the dosing output more stable.

[0025] By using two sets of dosing pipes to pump the chemicals together, the two sets of dosing pumps can work in concert to achieve the pumping action of the chemicals.

[0026] By operating two sets of dosing pumps separately and adjusting the ratio of a1 to a2, the overall flow rate of the flow measurement system can be controlled, making the overall flow rate value of the flow measurement system as close as possible to the standard value, thereby improving the control accuracy of the flow measurement system. Attached Figure Description

[0027] Figure 1 This is a perspective view of a flow measurement system according to Embodiment 1;

[0028] Figure 2 This is a front view of a flow measurement system according to Embodiment 1;

[0029] Figure 3 This is a schematic diagram of the diaphragm damper in Example 1;

[0030] Figure 4 This is a schematic diagram of the drug pump flow rate in Example 2. Figure 1 ;

[0031] Figure 5 This is a schematic diagram of the drug pump flow rate in Example 2. Figure 2 .

[0032] Reference numerals: Inlet pipe 1; Outlet pipe 2; Flow meter 21; Dosing pipe assembly 3; Input end 31; Output end 32; Dosing pump 33; Valve body 1 34; Connecting pipe 4; Safety device 5; First port 51; Second port 52; Pressure gauge 1 6; Valve body 2 61; Buffer pipe 7; Diaphragm damper 71; Valve body 2 72; Diaphragm 711; First chamber 712; Second chamber 713; Pressure gauge 2 714. Detailed Implementation

[0033] 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.

[0034] Example 1

[0035] This embodiment discloses a flow measurement system, referring to... Figures 1-3 As shown, the components of the system are supported by a frame, including an inlet pipe 1, an outlet pipe 2, and a dosing pipe assembly 3. The dosing pipe assembly 3 has an input end 31 and an output end 32 at both ends. The input end 31 is connected to the inlet pipe 1, and the output end 32 is connected to the outlet pipe 2.

[0036] A dosing pump 33 is installed in the middle section of the dosing tubing assembly 3. The dosing pump 33 can be a diaphragm metering pump, which can pump the reagent that needs to be added. The dosing pump 33 can pump the reagent from the input end 31 to the output end 32 and can perform metering; the pumping volume is basically consistent each time, and a pulse-like pumping addition can be formed during the pumping process.

[0037] A valve body 34 is installed on both the input and output sides of the dosing pump 33, and the connection of the dosing pump 33 to the pipeline system can be controlled through the valve body 34.

[0038] A flow meter 21 is installed at the outlet pipe 2. The flow meter 21 can directly detect the amount of medicine output by the system, and can obtain the current delivery flow rate and the total cumulative amount over a certain period of time, thereby accurately obtaining the actual output flow rate of the system.

[0039] In this embodiment, the flow measurement system also includes a buffer tube 7. One end of the buffer tube 7 is connected to the output end 32 of the dosing tube assembly 3, and the other end is fitted with a diaphragm damper 71. By connecting the diaphragm damper 71 to the output end 32 of the system, the diaphragm damper 71 can provide damping and buffering.

[0040] Because the dosing pump 33 delivers the drug in pulses each time, the diaphragm damper 71 can buffer the flow through pressure, making the system output flow smoother. When the dosing pump 33 pumps, the pressure at the output end 32 will increase significantly. At this time, some of the drug can be buffered and enter the diaphragm damper 71, and then the diaphragm damper 71 will release it slowly under pressure, preventing the output from changing too quickly.

[0041] In the flow measurement system of this embodiment, a pressure gauge 6 is also provided, which can detect the pressure at the output end 32 of the dosing pipe assembly 3. The pressure P1 at the output end 32 of the dosing pipe assembly 3 is detected by the pressure gauge 6.

[0042] Specific reference Figure 3 As shown, the inner cavity of the diaphragm damper 71 is provided with a diaphragm 711, which divides the inner cavity of the diaphragm damper 71 into two chambers, namely the first chamber 712 and the second chamber 713. The first chamber 712 is connected to the buffer tube 7, and a pressure gauge 714 is installed in the second chamber 713. A certain amount of air pressure is pre-filled into the second chamber 713.

[0043] Since the first chamber 712 is connected to the output end 32 of the dosing tube assembly 3 via the buffer tube 7 and the connecting tube 4, the pressure detected by pressure gauge 6 is the pressure of the first chamber 712. The pressure on both sides of the diaphragm 711 can be detected by pressure gauge 6 and pressure gauge 714, and the damping buffering effect can be adjusted according to the pressure.

[0044] During the pumping process, pressure P1 at the output end 32 of the dosing pipe assembly 3 is monitored by pressure gauge 6, and internal pressure P2 of the diaphragm damper 71 is monitored by pressure gauge 714. By maintaining an appropriate pressure in the diaphragm damper 71, the agent can be released evenly in the pipeline.

[0045] In addition, to prevent excessive pressure at the output end 32 of the dosing pipe assembly 3, a safety valve 5 is also installed in the flow measurement system. When the pressure is too high, the pressure can be released through the safety valve 5 to prevent pipeline rupture and other unstable situations.

[0046] Safety valve 5 has a first port 51 and a second port 52. The first port 51 is connected to the output end 32 of the dosing tubing assembly 3, and the second port 52 is also connected to the output end 32 of the dosing tubing assembly 3. Safety valve 5 allows pressure to be released from the second port 52 to the first port 51. When the pressure at the second port 52 (i.e., output end 32) of safety valve 5 does not exceed a set value, safety valve 5 is in the closed state; when the pressure at the second port 52 (i.e., output end 32) of safety valve 5 exceeds the set value, safety valve 5 can open, allowing some of the agent at the output end 32 to flow back to the input end 31 of the dosing tubing assembly 3, preventing excessive pressure from causing equipment failure and avoiding excessive pressure on the diaphragm damper 71.

[0047] In the flow measurement system of this embodiment, two sets of dosing pipe groups 3 are provided, which are connected in parallel. The output ends 32 of the two sets of dosing pipe groups 3 are connected by a connecting pipe 4, and the buffer pipe 7 is connected to the output ends 32 of the dosing pipe groups 3 through the connecting pipe 4. During pumping, the two sets of dosing pumps 33 work together to pump the dosing agent. The two sets of dosing pumps 33 cooperate to realize the pumping action of the agent.

[0048] Both sets of dosing pumps 33 can be diaphragm metering pumps, with pumping volumes a1 and a2 respectively each time. The pumping volume is basically stable each time. By counting the number of pumping operations, the cumulative pumping volume of dosing pump 33 can be obtained.

[0049] Example 2

[0050] This embodiment discloses a flow measurement system, which, based on Embodiment 1, further refers to... Figure 4 , Figure 5 Please provide a detailed explanation.

[0051] In this embodiment, the flow measurement system is also equipped with a pressure gauge 6 and a safety valve 5. The pressure gauge 6 can detect the pressure at the output end 32 of the dosing pipe assembly 3. The pressure P1 at the output end 32 of the dosing pipe assembly 3 is detected by the pressure gauge 6.

[0052] Reference Figure 4 As shown, the diaphragm damper 71 can buffer the pressure, making the system output flow smoother and able to buffer the pulsed pumping volume into a wave-like pattern (e.g., Figure 4 The horizontal axis represents time, and the vertical axis represents the dosing flow rate, which can improve the continuity of the dosing pump flow rate.

[0053] The pressure P1 at the output end 32 of the dosing pipe assembly 3 is detected by pressure gauge 6, and the internal pressure P2 of the diaphragm damper 71 is detected by pressure gauge 714. By maintaining an appropriate pressure in the diaphragm damper 71, the agent can be released evenly in the pipeline.

[0054] Pressures P1 and P2 should be maintained within an appropriate range, with 0.5P2 < P1 < 0.75P2, to ensure uniform release of the reagent in the pipeline. Adjusting pressures P1 and P2 can make the reagent pumping flow smoother, improving the stability of reagent addition. For example, refer to... Figure 5 As shown.

[0055] Example 3

[0056] This embodiment discloses a flow control method, which uses a flow measurement system as described in Embodiment 1 or Embodiment 2 to control the pumping flow rate of the agent.

[0057] In this embodiment, the pumping amounts of the two sets of dosing pumps 33 are a1 and a2 respectively each time, and there is a deviation between the pumping amounts a1 and a2 of the two sets of dosing pumps 33.

[0058] Within a unit time t, the preset dosage of the flow measurement system is 'a', where a1 < a < a2. 'a' can be considered the standard value, a1 is a smaller value, and a2 is a larger value. By operating two sets of dosing pumps 33 respectively and adjusting the ratio of a1 to a2, the overall flow rate of the flow measurement system can be controlled, ensuring that the overall flow rate value of the flow measurement system approaches the standard value as closely as possible, thereby improving the control accuracy of the flow measurement system.

[0059] In this embodiment, i is defined as the time-based count, and i = i + 1 at each time interval t. n is defined as the pumping count of the first group of dosing pumps 33, and n = n + 1 for each pumping operation. m is defined as the pumping count of the second group of dosing pumps 33, and m = m + 1 for each pumping operation. At each time interval t, one of the two groups of dosing pumps 33 is selected to pump once, i = n + m, and the total number of pumping operations performed by the two groups of dosing pumps 33 is consistent with the time-based count i.

[0060] Specifically, in this embodiment, the specific steps of the flow control method are as follows:

[0061] Two sets of dosing pumps 33 alternately perform pumping. At each interval t, the flow meter 21 detects the flow rate and records the actual total flow rate under the current state as V'(i). The current system preset total flow rate is V(i), which is the flow rate value under the ideal state and can be calculated as V(i) = a·i.

[0062] Since the dosage of the dosing pump 33 has a certain deviation, by combining the smaller deviation with the larger deviation, the resulting values ​​V'(i) and V(i) will have a certain difference. Based on the deviation between V'(i) and V(i), the corresponding dosing pump 33 is controlled to perform pumping, which can compensate for the deviation. As the pumping volume accumulates, the system can tend to stabilize and maintain the deviation between V'(i) and V(i) within a stable range.

[0063] By comparing the magnitudes of V'(i) and V(i), and then calculating the deviation between V'(i) and V(i), the percentage deviation rate K is calculated as follows: K = |V'(i) - V(i)| / V(i). The deviation rate K represents the deviation between the actual reagent supply and the pre-approved standard quantity, thus determining the reagent dosing status. Through flow control, the deviation rate of the entire dosing system can be maintained within the pre-approved deviation range.

[0064] When V'(i) is greater than V(i) and the deviation rate exceeds the preset deviation rate Q1, the first group of dosing pumps 33 will be selected for pumping next. Since the actual reaction flow rate V'(i) is too large, selecting the first group of dosing pumps 33 with a smaller pumping volume can gradually reduce the actual reaction flow rate V'(i), allowing it to approach V(i) and keeping the deviation between the two within the preset deviation rate Q1.

[0065] When V'(i) is less than V(i) and the deviation rate exceeds the preset deviation rate Q1, the second set of dosing pumps 33 will be selected for pumping next. Since the actual reaction flow rate V'(i) is small, selecting the second set of dosing pumps 33 with a smaller pumping volume can gradually increase the actual reaction flow rate V'(i), so that the actual reaction flow rate V'(i) can approach V(i), and the deviation between the two can be controlled within the preset deviation rate Q1.

[0066] Furthermore, in this embodiment, the pumping values ​​a1 and a2 of the two sets of dosing pumps 33 are limited for each pumping operation. The deviation rates of a1 and a2 from a dosing pump a do not exceed a preset deviation rate Q2, thus avoiding excessive deviation between the pumping value of the dosing pump 33 and the standard value a. Limiting the pumping values ​​a1 and a2 of the dosing pump 33 to a more accurate state can improve the initial accuracy of the system and also improve the accuracy of the single pumping volume.

[0067] Specifically, the preset deviation rate Q2 is 3.0%-5.0%. It is generally 5.0%, and can be selected according to the accuracy requirements.

[0068] The preset deviation rate Q1 is the deviation rate of the system under stable pumping conditions, reflecting the system's accuracy in this state. The preset deviation rate Q1 should be smaller than the preset deviation rate Q2, typically between 0.5% and 1.0%. By using dosing pumps 33, which have larger deviation rates, in cooperation, a higher precision operating state can be achieved, improving the accuracy of the system's output after stabilization. The method in this embodiment allows for the accumulation of higher precision through cumulative operation using a lower-precision pumping device, significantly improving the operational stability of the dosing equipment and the accuracy of the dosing dosage.

[0069] As the system continues to operate, after each pumping operation, the dosing pump 33 will experience minor wear inside. Each instance of wear will gradually accumulate, and long-term accumulation may affect the system's operational accuracy and stability.

[0070] Furthermore, in this embodiment, after each pumping operation, the two sets of dosing pumps 33 reset the corresponding pumping quantities a1 and a2. That is, the pumping quantities a1 and a2 of the dosing pumps 33 will be counted separately according to the actual situation to ensure the accuracy of the pumping quantity.

[0071] Specifically, when the first group of dosing pumps 33 performs pumping, the flow meter 21 displays the actual total flow rate as V'(i). The actual pumping amount a1 = V'(i) - V'(i-1) is recorded again. Similarly, when the second group of dosing pumps 33 performs pumping, the flow meter 21 displays the actual total flow rate as V'(i). The actual pumping amount a1 = V'(i) - V'(i-1) is recorded again.

[0072] By reassigning values ​​to the pumping quantities a1 and a2, it can be ensured that the pumping quantity of the dosing pump 33 can approach the actual value during the calculation process, thus ensuring the accuracy of the pumping execution quantity and improving the actual pumping accuracy of the overall system.

[0073] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A flow control method, characterized in that, A flow measurement system is adopted, which includes a dosing tube assembly (3). The dosing tube assembly (3) has an input end (31) and an output end (32) at both ends. The input end (31) is connected to the inlet pipe (1), and the output end (32) is connected to the outlet pipe (2). A dosing pump (33) is installed in the middle section of the dosing tube assembly (3). The dosing pump (33) is used to pump the reagent from the input end (31) to the output end (32) and can perform metering. A flow meter (21) is installed in the outlet pipe (2). There are two sets of dosing tube assemblies (3), and the two sets of dosing tube assemblies (3) are set in parallel. The two sets of dosing pumps (33) pump out amounts a1 and a2 respectively each time; within a unit time t, the system preset dosing amount is a, a1 < a < a2; i represents the number of pumping operations over time t, where i = i + 1; n represents the number of pumping operations of the first group of dosing pumps (33), where n = n + 1 for each pumping operation; m represents the number of pumping operations of the second group of dosing pumps (33), where m = m + 1 for each pumping operation; and at each time interval t, one of the two groups of dosing pumps (33) is selected to pump once, where i = n + m. The flow control method includes the following steps: two sets of dosing pumps (33) alternately perform pumping, and at each interval t, the flow meter (21) detects the flow and records the actual total flow as V'(i); the current system preset total flow is V(i), V(i) = a·i; By comparing the magnitudes of V'(i) and V(i), and then calculating the deviation between V'(i) and V(i), the deviation rate K is calculated, K=|V'(i)-V(i)| / V(i); When V'(i) is greater than V(i) and the deviation rate K exceeds the preset deviation rate Q1, the first group of dosing pumps (33) will be selected for pumping next time. When V'(i) is less than V(i) and the deviation rate K exceeds the preset deviation rate Q1, the second group of dosing pumps (33) will be selected for pumping next time. After each pumping operation, the two sets of dosing pumps (33) reset the corresponding pumping volumes a1 and a2. When the first group of dosing pumps (33) performs pumping, the flow meter (21) displays the actual total flow rate as V'(i). Here, the actual pumping amount a1 = V'(i) - V'(i-1) is pumped. The pumping amount a1 of the first group of dosing pumps (33) is recorded again. When the second group of dosing pumps (33) performs pumping, the flow meter (21) displays the actual total flow rate as V'(i). Here, the actual pumping amount a1 = V'(i) - V'(i-1) is pumped, and the pumping amount a2 of the second group of dosing pumps (33) is recorded again.

2. The flow control method according to claim 1, characterized in that, The deviation rates of a1 and a2 from a respectively do not exceed the preset deviation rate Q2.

3. The flow control method according to claim 2, characterized in that, The preset deviation rate Q1 is less than the preset deviation rate Q2; the preset deviation rate Q2 is 3.0%-5.0%, and the preset deviation rate Q1 is 0.5%-1.0%.

4. The flow control method according to claim 1, characterized in that, During the pumping process, the pressure P1 at the output end (32) of the dosing pipe group (3) is detected by pressure gauge 1 (6), and the internal pressure P2 of the diaphragm damper (71) is detected by pressure gauge 2 (714), where 0.5P2 < P1 < 0.75P2.

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