A caustic solution metering system

Abstract

The application discloses a lye metering system and belongs to the technical field of water treatment. The lye metering system comprises a metering tank, which is used for storing lye and transmitting the lye to a regeneration system of ion exchange resin. The lye metering system further comprises a breathing pipe, which is connected to the metering tank and is used for balancing the internal and external pressures of the metering tank. The lye metering system further comprises an overflow sampling device. The overflow sampling device comprises a sampling piece, which is connected to the breathing pipe and is used for storing lye overflowing from the metering tank to the breathing pipe. The overflow sampling device further comprises a liquid level monitoring switch, which is arranged on the sampling piece and is used for outputting a switch signal according to the liquid level of the lye in the sampling piece. The overflow sampling device has little influence on the original structure and control system of the lye metering system, and the delay of the overflow sampling device in monitoring the overflow condition of the metering tank is low and the response speed is fast.

Description

Technical Field

[0001] This application relates to the field of water treatment technology, and in particular to an alkaline solution metering system. Background Technology

[0002] In industrial pure water production systems, ion exchange resins need to be regenerated periodically to restore their exchange capacity. During the regeneration process, a measured amount of alkaline solution (such as sodium hydroxide solution) is drawn from the metering tank and injected into the regeneration system through an ejector.

[0003] The normal operation of the ejector depends on specific inlet water flow and pressure. When problems such as insufficient inlet water pressure, nozzle blockage, or pipeline leaks occur, the resulting negative pressure is insufficient to draw up the alkali solution. Instead, water in the system may backflow into the alkali metering tank through the suction pipe, causing an abnormal rise in the tank level until overflow from the breather. To avoid affecting the ejector's suction efficiency, check valves are typically not installed on process pipelines, further increasing the risk of backflow. Furthermore, the inlet to the alkali metering tank is usually controlled by a float switch or level switch. If these control components malfunction (e.g., a stuck float or a faulty switch), the inlet valve may fail to close properly, continuously adding chemicals to the already full metering tank, also causing overflow. Alkali solution is highly corrosive; accidental leakage can seriously endanger equipment and personnel safety, and pollute the environment.

[0004] Currently, the system typically requires the integration of additional monitoring devices to monitor metering tank overflow. Installing these additional devices usually significantly impacts the existing system structure and control system. Furthermore, current monitoring devices typically monitor metering tank overflow by issuing commands based on upper-level computer logic, resulting in a delayed response. Utility Model Content

[0005] This application provides an alkali metering system, whose overflow sampling device has little impact on the original structure and control system of the alkali metering system, and the overflow sampling device has a low delay in monitoring the overflow of the metering tank and a fast response speed.

[0006] To achieve the above objectives, according to a first aspect of this application, an alkali metering system is provided. The alkali metering system includes a metering tank for storing alkali and for transferring alkali to a regeneration system for ion exchange resins. The system also includes a breather tube connected to the metering tank for balancing the internal and external pressures of the tank. Furthermore, the system includes an overflow sampling device. This overflow sampling device includes a sampling element connected to the breather tube, which stores alkali overflowing from the metering tank into the breather tube. The overflow sampling device also includes a level monitoring switch disposed on the sampling element, which outputs a switching signal based on the alkali level in the sampling element.

[0007] Optionally, the sampling device includes a horizontal pipe section and a vertical pipe section. The horizontal pipe section is connected to the breathing tube, and the vertical pipe section is connected to the horizontal pipe section. The vertical pipe section is used to store the alkaline solution overflowing from the metering tank into the breathing tube. A liquid level monitoring switch is installed in the vertical pipe section and is used to output a switching signal according to the liquid level of the alkaline solution in the vertical pipe section.

[0008] Optionally, the breathing tube includes a first breathing sub-tube and a second breathing sub-tube, which are respectively connected to the opposite ends of the horizontal pipe section. The inside of the metering tank is connected to the outside through the first breathing sub-tube, the horizontal pipe section and the second breathing sub-tube in sequence.

[0009] Optionally, the liquid level monitoring switch includes a guide rod and a float movably disposed on the guide rod, the float being used to monitor the liquid level of the alkaline solution in the sampling piece.

[0010] Optionally, the overflow sampling device also includes a drain valve connected to the sampling element, which is used to drain the alkaline solution in the sampling element.

[0011] Optionally, the alkali metering system also includes a power supply and a first control circuit, the power supply having a positive terminal and a negative terminal; wherein, the first control circuit includes: a reset switch; and an intermediate relay, the level monitoring switch, the reset switch, and the intermediate relay being connected in series between the positive and negative terminals; when the level monitoring switch is closed, the intermediate relay is energized to cause the alkali metering system to output an alarm signal, and the reset switch is used to disconnect the electrical connection between the intermediate relay and the power supply.

[0012] Optionally, the intermediate relay has a first contact, which is connected in parallel with the liquid level monitoring switch between the positive and negative terminals; when the liquid level monitoring switch is closed, the intermediate relay is energized, causing the first contact to close.

[0013] Optionally, the alkali metering system further includes an outlet pipeline, an outlet pneumatic valve, and a first solenoid directional valve. The outlet pneumatic valve is located in the outlet pipeline, and the first solenoid directional valve is connected to the outlet pneumatic valve. The alkali metering system also includes an inlet pipeline, an inlet pneumatic valve, and a second solenoid directional valve. The inlet pneumatic valve is located in the inlet pipeline, and the second solenoid directional valve is connected to the inlet pneumatic valve. The alkali metering system also includes a second control circuit, which is connected in parallel with the first control circuit between the positive and negative terminals. The second control circuit includes a first branch and a second branch connected in parallel. The intermediate relay has a second contact and a third contact. The second contact and the coil of the first solenoid directional valve are connected in series in the first branch, and the third contact and the coil of the second solenoid directional valve are connected in series in the second branch. When the liquid level monitoring switch is closed, the intermediate relay is energized, causing the second and third contacts to close, so that the first solenoid directional valve controls the outlet pneumatic valve to block the outlet pipeline, and the second solenoid directional valve controls the inlet pneumatic valve to block the inlet pipeline.

[0014] Optionally, the second control circuit also includes a manual / automatic switch, which is connected in series with the first branch and the second branch respectively. The manual / automatic switch is used to disconnect the electrical connection between the first branch and the second branch and the power supply.

[0015] Optionally, the alkali metering system further includes a third solenoid directional valve and a fourth solenoid directional valve; the pilot air paths of the first solenoid directional valve and the third solenoid directional valve are connected in series in the system air path of the outlet pneumatic valve, and the third solenoid directional valve is used to control the outlet pneumatic valve to open or close the outlet pipeline; the pilot air paths of the second solenoid directional valve and the fourth solenoid directional valve are connected in series in the system air path of the inlet pneumatic valve, and the fourth solenoid directional valve is used to control the inlet pneumatic valve to open or close the inlet pipeline.

[0016] In the alkali metering system of this application embodiment, the overflow sampling device includes a sampling element and a liquid level monitoring switch. The sampling element is connected to the breather tube, and the liquid level monitoring switch is located on the sampling element. The liquid level monitoring switch outputs a switching signal based on the liquid level of the alkali in the sampling element, so as to issue a signal when the metering tank overflows, thereby prompting and alarming the overflow situation. The overflow sampling device of this application embodiment samples from the breather tube, which minimizes the impact of the overflow sampling device on the original structure and control system of the alkali metering system, making construction simple and safe and reliable. Furthermore, in this application embodiment, the sampling element stores the alkali overflowing from the metering tank to the breather tube, and the liquid level monitoring switch outputs a switching signal based on the liquid level of the alkali in the sampling element, i.e., monitoring the overflow situation of the metering tank. This method has low latency and fast response speed.

[0017] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0019] Figure 1 This is a schematic diagram of the structure of an embodiment of the alkali metering system of this application; Figure 2 This is a schematic diagram of an embodiment of the control cabinet of this application; Figure 3 This is a schematic diagram of an embodiment of the control circuit of the alkali metering system of this application.

[0020] Explanation of reference numerals in the attached figures: 1-Metering tank; 2-Breathing tube; 21-First breathing sub-tube; 22-Second breathing sub-tube; 3-Overflow sampling device; 31-Sampling component; 311-Horizontal pipe section; 312-Vertical pipe section; 32-Level monitoring switch; 321-Guide rod; 322-Float ball; 33-Drain valve; 4-Power supply; 41-Positive terminal; 42-Negative terminal; 5-First control circuit; 51-Reset switch; 52-Intermediate relay; 521-First contact; 522-Second contact; 523-Third contact; 6-Second control circuit; 61-First branch; 62-Second branch; 63-Manual / automatic switch; 71-Outlet pipe; 72-Outlet pneumatic valve; 73-First solenoid directional valve; 74-Ejector; 81-Inlet pipe; 82-Inlet pneumatic valve; 83-Second solenoid directional valve. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0022] To address the technical problems of existing monitoring devices significantly impacting the original structure and control system, and exhibiting slow response times, this application provides an alkali metering system. The alkali metering system includes a metering tank for storing alkali and transferring it to the regeneration system of an ion exchange resin. It also includes a breather tube connected to the metering tank for balancing the internal and external pressures. Furthermore, the system includes an overflow sampling device. This overflow sampling device includes a sampling element connected to the breather tube, which stores the alkali overflowing from the metering tank into the breather tube. The overflow sampling device also includes a level monitoring switch located on the sampling element, which outputs a switching signal based on the alkali level in the sampling element. This will be described in detail below.

[0023] Please see Figure 1 , Figure 1 This is a schematic diagram of an embodiment of the alkali metering system of this application.

[0024] In one embodiment, the alkali metering system can be applied to the regeneration stage of ion exchange resin in an industrial pure water manufacturing system. The alkali metering system includes a metering tank 1, which stores alkali and is used to transfer alkali to the ion exchange resin regeneration system. The system also includes a breather tube 2 connected to the metering tank 1, used to balance the internal and external pressures of the metering tank 1. The system further includes an overflow sampling device 3. This device includes a sampling element 31 connected to the breather tube 2, used to store alkali overflowing from the metering tank 1 into the breather tube 2. The device also includes a level monitoring switch 32 located on the sampling element 31. This switch outputs a switching signal based on the alkali level in the sampling element 31, providing a signal when overflow occurs in the metering tank 1, thus alerting and alarming the overflow situation.

[0025] In this embodiment, the overflow sampling device 3 samples from the breathing tube 2, minimizing its impact on the original structure and control system of the alkali metering system. This method is simple to implement and highly reliable. Furthermore, in this embodiment, the sampling element 31 stores the alkali overflowing from the metering tank 1 into the breathing tube 2. The level monitoring switch 32 outputs a switching signal based on the alkali level in the sampling element 31, thus monitoring the overflow of the metering tank 1. This method exhibits low latency and fast response.

[0026] In one embodiment, the sampling device 31 includes a horizontal tube section 311 and a vertical tube section 312. The horizontal tube section 311 is connected to the breathing tube 2, and the vertical tube section 312 is connected to the horizontal tube section 311. The vertical tube section 312 is used to store the alkaline solution overflowing from the metering tank 1 into the breathing tube 2. A liquid level monitoring switch 32 is disposed in the vertical tube section 312 and is used to output a switching signal according to the liquid level of the alkaline solution in the vertical tube section 312.

[0027] The breathing tube 2 includes a first breathing sub-tube 21 and a second breathing sub-tube 22. The first breathing sub-tube 21 and the second breathing sub-tube 22 are respectively connected to the opposite ends of the horizontal tube section 311. The interior of the metering tank 1 is connected to the outside through the first breathing sub-tube 21, the horizontal tube section 311 and the second breathing sub-tube 22 in sequence.

[0028] For example, in this embodiment, the sampling component 31 can be a T-shaped tee fitting, etc. The horizontal pipe section 311 of the sampling component 31 is connected to the first breathing tube 21 and the second breathing tube 22 at both ends, respectively. The vertical pipe section 312 is connected to the horizontal pipe section 311, and a liquid level monitoring switch 32 is provided on the vertical pipe section 312. The length of the vertical pipe section 312 can be approximately 300 mm. The liquid level monitoring switch 32 includes a guide rod 321 and a float 322 movably disposed on the guide rod 321. The float 322 is used to monitor the liquid level of the alkaline solution in the sampling component 31. The sampling component 31 can have a top opening to install the liquid level monitoring switch 32 onto the vertical pipe section 312.

[0029] When metering tank 1 overflows, the overflowing alkaline solution flows into the vertical pipe section 312 of sampling element 31 through the first breathing tube 21. When the alkaline solution level in the vertical pipe section 312 reaches the set level, the float 322 rises, triggering the liquid level monitoring switch 32 to output a switching signal. This embodiment uses a direct mechanical float 322 (corrosion-resistant) switch for detection, which is highly sensitive, has extremely low delay, and achieves interlocking control through hard-wired circuitry. Its response speed is much faster than the method of issuing commands based on upper-level computer logic judgment, resulting in extremely high reliability. It is understood that the liquid level monitoring switch 32 in this embodiment utilizes the design principle of a float switch, and the principle of the float 322 rising to trigger the liquid level monitoring switch 32 to output a switching signal is within the scope of understanding for those skilled in the art and will not be elaborated upon here.

[0030] The overflow sampling device 3 also includes a drain valve 33, which is connected to the sampling element 31 and is used to discharge the alkaline solution in the sampling element 31. Specifically, the drain valve 33 is installed after the diameter of the vertical pipe section 312 of the sampling element 31 is reduced. The alkaline solution in the vertical pipe section 312 is discharged through the drain valve 33, causing the float 322 to sink and reset, so as to continue monitoring the overflow of the metering tank 1. During the process of the liquid level monitoring switch 32 monitoring the overflow of the metering tank 1, the drain valve 33 is in the closed state. The drain valve 33 can be a manual ball valve, etc., and is not limited here.

[0031] It should be noted that the breathing tube 2 is connected to the breathing port of the metering tank 1, serving to balance the pressure inside and outside the metering tank 1. In this embodiment, the overflow sampling device 3 is integrated into the breathing tube 2. It receives the overflowing alkali solution from the metering tank 1 through the vertical pipe section 312 of the sampling element 31, and the overflow situation of the metering tank 1 is monitored by the liquid level monitoring switch 32. Furthermore, the interior of the metering tank 1 is connected to the outside through the first breathing sub-tube 21, the horizontal pipe section 311, and the second breathing sub-tube 22 in sequence, ensuring that the breathing tube 2 can still play a role in pressure balance. In this embodiment, the overflow sampling device 3 has little impact on the original structure and control system of the alkali solution metering system, is simple to construct, and is safe and reliable.

[0032] Please see Figure 2and Figure 3 , Figure 2 This is a schematic diagram of an embodiment of the control cabinet of this application. Figure 3 This is a schematic diagram of an embodiment of the control circuit of the alkali metering system of this application.

[0033] In one embodiment, the alkali metering system further includes a power supply 4 and a first control circuit 5. The power supply 4 has a positive terminal 41 and a negative terminal 42. The first control circuit 5 includes a reset switch 51 and an intermediate relay 52. ​​The level monitoring switch 32, the reset switch 51, and the intermediate relay 52 are connected in series between the positive terminal 41 and the negative terminal 42. When the level monitoring switch 32 is closed, the intermediate relay 52 is energized to cause the alkali metering system to output an alarm signal, and the reset switch 51 is used to disconnect the electrical connection between the intermediate relay 52 and the power supply 4.

[0034] Reset switch 51 is normally closed. When metering tank 1 overflows, the switch signal output by level monitoring switch 32 is a closing signal, that is, level monitoring switch 32 closes, which makes intermediate relay 52 electrically connected to power supply 4. Power supply 4 supplies power to intermediate relay 52, causing the alkali metering system to output an alarm signal to notify the staff that metering tank 1 has overflowed.

[0035] Furthermore, the intermediate relay 52 has a first contact 521, which is connected in parallel with the level monitoring switch 32 between the positive terminal 41 and the negative terminal 42. The first contact 521 is a normally open contact. When the level monitoring switch 32 is closed, the intermediate relay 52 is energized, causing the first contact 521 to close. In this embodiment, after the intermediate relay 52 is energized, the first contact 521 closes to achieve self-locking. Thus, even if the float 322 sinks and causes the level monitoring switch 32 to open, the intermediate relay 52 remains electrically connected to the power supply 4 through the first contact 521 until the operator controls the reset switch 51 to open, at which point the intermediate relay 52 will be de-energized.

[0036] In one embodiment, the alkali metering system further includes an outlet pipe 71, an outlet pneumatic valve 72, and a first solenoid directional valve 73. The outlet pneumatic valve 72 is disposed on the outlet pipe 71, and the first solenoid directional valve 73 is connected to the outlet pneumatic valve 72. An ejector 74 is connected to the outlet pipe 71. The alkali metering system also includes an inlet pipe 81, an inlet pneumatic valve 82, and a second solenoid directional valve 83. The inlet pneumatic valve 82 is disposed on the inlet pipe 81, and the second solenoid directional valve 83 is connected to the inlet pneumatic valve 82.

[0037] The alkali metering system also includes a second control circuit 6, which is connected in parallel with the first control circuit 5 between the positive terminal 41 and the negative terminal 42. The second control circuit 6 includes a first branch 61 and a second branch 62 connected in parallel. The intermediate relay 52 has a second contact 522 and a third contact 523. The second contact 522 and the coil of the first solenoid directional valve 73 are connected in series in the first branch 61, and the third contact 523 and the coil of the second solenoid directional valve 83 are connected in series in the second branch 62. When the liquid level monitoring switch 32 is closed, the intermediate relay 52 is energized, causing the second contact 522 and the third contact 523 to close, so that the first solenoid directional valve 73 controls the outlet pneumatic valve 72 to block the outlet pipe 71, and the second solenoid directional valve 83 controls the inlet pneumatic valve 82 to block the inlet pipe 81.

[0038] Both the second contact 522 and the third contact 523 are normally open contacts. When the metering tank 1 overflows, the liquid level monitoring switch 32 closes, the intermediate relay 52 is energized, causing the second contact 522 and the third contact 523 to close. This causes the first solenoid directional valve 73 to control the outlet pneumatic valve 72 to block the outlet pipe 71, and the second solenoid directional valve 83 to control the inlet pneumatic valve 82 to block the inlet pipe 81, thus terminating the continued output of alkali solution from the metering tank 1 and stopping the liquid from entering the metering tank, completely eliminating the overflow source.

[0039] In existing technologies, systems rely solely on high-level alarms from the metering tank to alert personnel. The supervisory control and data acquisition (SCADA) system cannot distinguish whether the increase in liquid level is due to normal dosing, water backflow, or a control malfunction. High-level alarms from the metering tank require manual on-site confirmation, resulting in a delayed response and an inability to proactively cut off the risk source before overflow occurs. This embodiment proactively cuts off the overflow risk source before the overflow becomes severe. Whether the increase in liquid level is caused by backflow from the ejector 74 or a malfunction in the inlet control, as long as the alkali solution overflows to the sampling element 31, it can be effectively monitored and triggered to block the outlet pipe 71 and the inlet pipe 81, providing comprehensive protection. Furthermore, in this embodiment, the liquid level monitoring switch 32, intermediate relay 52, and their contacts all employ a "power-on, valve-off" interlocking logic, ensuring that the liquid level monitoring switch 32 and intermediate relay 52 will not malfunction and interfere with normal production in the event of system power failure or malfunction; they will only activate when protection is truly necessary.

[0040] Furthermore, the second control circuit 6 also includes a manual / automatic switch 63, which is connected in series with the first branch 61 and the second branch 62. The manual / automatic switch 63 is used to disconnect the electrical connection between the first branch 61 and the second branch 62 and the power supply 4. The manual / automatic switch 63 is normally closed. In this embodiment, by setting the manual / automatic switch 63, when an abnormal situation occurs, the operator controls the manual / automatic switch 63 to open, thereby de-energizing the first solenoid reversing valve 73 and the second solenoid reversing valve 83, and reconnecting the outlet pipe 71 and the inlet pipe 81.

[0041] It should be noted that, in this embodiment, by setting a reset switch 51, after the overflow of metering tank 1 has been handled, the operator confirms on-site and controls the reset switch 51 to open. At this time, the intermediate relay 52 is de-energized, and the first contact 521, the second contact 522, and the third contact 523 are all open, causing the first solenoid directional valve 73 and the second solenoid directional valve 83 to be de-energized, and the outlet pipeline 71 and the inlet pipeline 81 to be reconnected. This embodiment, by setting a reset switch 51 and a manual / automatic switch 63, facilitates maintenance, debugging, and emergency intervention by the operator, improving the operability and flexibility of the system.

[0042] In one embodiment, the alkali metering system further includes a third solenoid directional valve and a fourth solenoid directional valve (not shown). The pilot air paths of the first solenoid directional valve 73 and the third solenoid directional valve are connected in series in the system air path of the outlet pneumatic valve 72. The third solenoid directional valve is used to control the outlet pneumatic valve 72 to open or close the outlet pipe 71. The pilot air paths of the second solenoid directional valve 83 and the fourth solenoid directional valve are connected in series in the system air path of the inlet pneumatic valve 82. The fourth solenoid directional valve is used to control the inlet pneumatic valve 82 to open or close the inlet pipe 81.

[0043] In other words, the third and fourth solenoid directional valves are the valve bodies that originally control the operation of the outlet pneumatic valve 72 and the inlet pneumatic valve 82. This embodiment adds a first solenoid directional valve 73 and a second solenoid directional valve 83 to the third and fourth solenoid directional valves. The pilot air paths of the first and third solenoid directional valves are connected in series in the system air path of the outlet pneumatic valve 72. The first solenoid directional valve 73 is configured to be normally open. Under normal conditions (i.e., when metering tank 1 does not overflow), the first solenoid directional valve 73 will not affect the normal control of the third solenoid valve to the outlet pneumatic valve 72 to block or open the outlet pipeline 71. Similarly, the pilot air paths of the second and fourth solenoid directional valves are connected in series in the system air path of the inlet pneumatic valve 82. The second solenoid directional valve 83 is configured to be normally open. Under normal conditions, the second solenoid directional valve 83 will not affect the normal control of the fourth solenoid valve to the inlet pneumatic valve 82 to block or open the inlet pipeline 81. In this embodiment, the first electromagnetic reversing valve 73 and the second electromagnetic reversing valve 83 have minimal impact on the original gas path and control system of the alkali metering system, and are simple to construct and safe and reliable.

[0044] The working process of the alkali metering system in the embodiments of this application is described below.

[0045] The application site of the alkali metering system is equipped with a control cabinet. The cable of the level monitoring switch 32 is connected to the control cabinet. The control cabinet is equipped with a power supply 4, which can be a 24V DC power supply. The positive terminal 41 of the power supply 4 is connected in series with the reset switch 51 and the level monitoring switch 32, and then connected to the coil of the intermediate relay 52. ​​The coil of the intermediate relay 52 is connected to the negative terminal 42. At the same time, the first contact 521 of the intermediate relay 52 is connected in parallel across the two ends of the level monitoring switch 32 to form a self-locking circuit. An outlet pneumatic valve 72 is installed on the outlet pipe 71 of the metering tank 1, and an inlet pneumatic valve 82 is installed on the inlet pipe 81. The air paths of both valves are controlled by two-position three-way or five-position three-way solenoid directional valves (i.e., the first solenoid directional valve 73 and the second solenoid directional valve 83). Connect the air inlets of the first solenoid directional valve 73 and the second solenoid directional valve 83 to the control air source of the original system, and connect their air outlets to the cylinder interfaces of the outlet pneumatic valve 72 and the inlet pneumatic valve 82. Under normal conditions, the first solenoid directional valve 73 and the second solenoid directional valve 83 are not energized, the air path is open, and the original system can normally control the opening and closing of the outlet pneumatic valve 72 and the inlet pneumatic valve 82.

[0046] After the positive terminal 41 is connected in series with the manual / automatic transfer switch, it splits into two parallel branches. The first branch 61: after connecting in series with the second contact 522 of the intermediate relay 52, it is connected to the coil of the first solenoid directional valve 73 corresponding to the outlet pneumatic valve 72; the second branch 62: after connecting in series with the third contact 523 of the intermediate relay 52, it is connected to the coil of the second solenoid directional valve 83 corresponding to the inlet pneumatic valve 82. The other ends of the coils of the first and second solenoid directional valves 73 are connected in parallel and then back to the negative terminal 42.

[0047] Normal state: The alkali solution level in metering tank 1 is normal, and there is no alkali solution overflowing into breather tube 2. There is no liquid in the vertical pipe section 312 of sampling unit 31, float 322 falls, liquid level monitoring switch 32 is disconnected, intermediate relay 52 is not energized, and first contact 521, second contact 522, and third contact 523 are all disconnected. The coils of first solenoid directional valve 73 and second solenoid directional valve 83 are not energized, keeping the air path unobstructed and not affecting the original system's control of outlet pneumatic valve 72 and inlet pneumatic valve 82.

[0048] Abnormal overflow condition: When backflow or overfilling occurs, the alkali solution overflows into the breathing tube 2 and enters the vertical tube section 312 of the sampling device 31. The liquid level in the vertical tube section 312 rises, pushing the float 322 to float upward, causing the liquid level monitoring switch 32 to close. The circuit is completed, and the coil of the intermediate relay 52 is energized.

[0049] Self-locking and interlocking: After the coil of intermediate relay 52 is energized, its first contact 521 closes instantaneously, achieving self-locking. Even if the float 322 subsequently falls and the level monitoring switch 32 is opened, intermediate relay 52 remains energized until the reset switch 51 is manually pressed. At the same time, the second contact 522 and the third contact 523 close. At this time, the manual / automatic switch 63 is in the closed state, and current flows through the second contact 522 and the third contact 523, energizing the coils of the first solenoid directional valve 73 and the second solenoid directional valve 83 simultaneously.

[0050] Shutdown Execution: The coils of the first solenoid directional valve 73 and the second solenoid directional valve 83 are energized, driving them to cut off the air supply to the outlet pneumatic valve 72 and the inlet pneumatic valve 82. The outlet pneumatic valve 72 and the inlet pneumatic valve 82 are then immediately closed by the action of the cylinder spring or actuator (fail-safe design), thereby terminating the continued output of alkali and stopping the inflow into the metering tank 1, completely eliminating the overflow source.

[0051] Reset: After the fault is resolved, manual on-site confirmation of safety is required. Press the reset switch 51 to de-energize and reset the intermediate relay 52, and the entire alkali metering system will return to its initial standby state.

[0052] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0053] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0054] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0055] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An alkaline solution metering system, characterized in that, include: Metering tanks are used to store alkali solutions and to transfer alkali solutions to the regeneration system of ion exchange resins. A breathing tube is connected to the metering tank, and the breathing tube is used to balance the internal and external pressure of the metering tank; as well as Overflow sampling device; The overflow sampling device includes: A sampling device, connected to the breathing tube, for storing alkali solution overflowing from the metering vessel into the breathing tube; and A liquid level monitoring switch is installed on the sampling element, and the liquid level monitoring switch is used to output a switching signal according to the liquid level of the alkaline solution in the sampling element.

2. The alkali metering system according to claim 1, characterized in that, The sampling device includes a horizontal pipe section and a vertical pipe section. The horizontal pipe section is connected to the breathing tube, and the vertical pipe section is connected to the horizontal pipe section. The vertical pipe section is used to store the alkaline solution overflowing from the metering tank into the breathing tube. The liquid level monitoring switch is installed in the vertical pipe section and is used to output a switching signal according to the liquid level of the alkaline solution in the vertical pipe section.

3. The alkali metering system according to claim 2, characterized in that, The breathing tube includes a first breathing sub-tube and a second breathing sub-tube, which are respectively connected to the opposite ends of the horizontal pipe section. The interior of the metering tank is connected to the outside through the first breathing sub-tube, the horizontal pipe section and the second breathing sub-tube in sequence.

4. The alkali metering system according to claim 1, characterized in that, The liquid level monitoring switch includes a guide rod and a float movably disposed on the guide rod, the float being used to monitor the liquid level of the alkaline solution in the sampling element.

5. The alkali metering system according to claim 1, characterized in that, The overflow sampling device also includes a drain valve connected to the sampling element, which is used to discharge the alkaline solution in the sampling element.

6. The alkali metering system according to claim 1, characterized in that, The alkaline solution metering system also includes a power supply and a first control circuit, wherein the power supply has a positive terminal and a negative terminal; The first control circuit includes: Reset switch; and An intermediate relay, the liquid level monitoring switch, the reset switch, and the intermediate relay are connected in series between the positive and negative terminals; when the liquid level monitoring switch is closed, the intermediate relay is energized to cause the alkali metering system to output an alarm signal, and the reset switch is used to disconnect the electrical connection between the intermediate relay and the power supply.

7. The alkali metering system according to claim 6, characterized in that, The intermediate relay has a first contact, which is connected in parallel with the liquid level monitoring switch between the positive and negative terminals; when the liquid level monitoring switch is closed, the intermediate relay is energized, causing the first contact to close.

8. The alkali metering system according to claim 6, characterized in that, The alkali metering system further includes an outlet pipeline, an outlet pneumatic valve, and a first solenoid directional valve. The outlet pneumatic valve is located in the outlet pipeline, and the first solenoid directional valve is connected to the outlet pneumatic valve. The alkali metering system also includes an inlet pipeline, an inlet pneumatic valve, and a second solenoid directional valve. The inlet pneumatic valve is located in the inlet pipeline, and the second solenoid directional valve is connected to the inlet pneumatic valve. The alkaline solution metering system further includes a second control circuit, which is connected in parallel with the first control circuit between the positive electrode and the negative electrode. The second control circuit includes a first branch and a second branch connected in parallel. The intermediate relay has a second contact and a third contact. The second contact and the coil of the first solenoid directional valve are connected in series in the first branch, and the third contact and the coil of the second solenoid directional valve are connected in series in the second branch. When the liquid level monitoring switch is closed, the intermediate relay is energized, causing the second contact and the third contact to close, so that the first solenoid directional valve controls the outlet pneumatic valve to block the outlet pipeline, and the second solenoid directional valve controls the inlet pneumatic valve to block the inlet pipeline.

9. The alkali metering system according to claim 8, characterized in that, The second control circuit also includes a manual / automatic switch, which is connected in series with the first branch and the second branch respectively. The manual / automatic switch is used to disconnect the electrical connection between the first branch and the second branch and the power supply.

10. The alkali metering system according to claim 8, characterized in that, The alkali metering system further includes a third electromagnetic reversing valve and a fourth electromagnetic reversing valve; the pilot air paths of the first electromagnetic reversing valve and the third electromagnetic reversing valve are connected in series in the system air path of the outlet pneumatic valve, and the third electromagnetic reversing valve is used to control the outlet pneumatic valve to open or close the outlet pipeline; the pilot air paths of the second electromagnetic reversing valve and the fourth electromagnetic reversing valve are connected in series in the system air path of the inlet pneumatic valve, and the fourth electromagnetic reversing valve is used to control the inlet pneumatic valve to open or close the inlet pipeline.

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