Bypass precision filtration pretreatment device and intelligent pretreatment system for high-turbidity water quality

Abstract

The invention belongs to the technical field of online determination of volatile organic compounds in surface water. The invention provides a bypass precision filtration pretreatment device. The bypass precision filtration pretreatment device comprises a sampling port, a filter element bracket, a backwashing port, a water sample cup cover, a metal filter element, a water sample cup, an overflow pipe, a water inlet and a water outlet, the filter element bracket is internally provided with a hollow pipeline, the middle part is provided with an external thread, the top is provided with a sampling port and a backwashing port, and the bottom is provided with an internal thread; the metal filter element is connected with an internal thread at the bottom of the filter element bracket through a top external thread; the sampling port and the reverse cleaning port are communicated with the upper part of the hollow pipeline of the filter element bracket; the filter element bracket is connected with an internal thread of the water sample cup cover through an external thread in the middle; the metal filter element is of a hollow structure. The device provided by the invention not only can meet normal measurement of a water sample in a high-turbidity environment, but also can automatically carry out various intelligent quality control measures such as standard sample checking, multi-point calibration and emergency quality control on the online volatile organic compound monitor.

Description

Technical Field

[0001] The invention belongs to the technical field of online determination of volatile organic matter in surface water. Background Art

[0002] The online determination of volatile organic compounds in surface water is generally divided into pretreatment units, purge and capture units, chromatography or mass spectrometry analysis units, control units, etc. Among them, the purge and capture units and the detection units are basically integrated using mature laboratory instrument methods, and there are no significant differences between the various schemes. However, due to the complexity of surface water samples, the pretreatment unit also has a great impact on the consistency and repeatability of sample determination. And due to the characteristics of volatile organic compound monitoring instruments, the long-term stability of the instrument is not as good as that of traditional chemical instruments, and regular manual maintenance and calibration are required during on-site installation.

[0003] Prior art CN117517034A is a sample pretreatment system for volatile organic pollutants in water. When encountering flood season or high turbidity river basin, the instrument protection measures will be automatically activated, which will seriously affect the test data efficiency.

[0004] As a new product form, the online water quality monitor for volatile organic compounds still has many pain points in application. First of all, since most instruments use experimental instruments or simple transformation and integration, it is necessary to separately design pre-treatment and sampling devices that meet the instrument and field monitoring needs (turbidity pretreatment, pipeline backwashing); secondly, as detectors of volatile organic compounds, instruments such as gas phase / gas phase mass spectrometry are affected by field environmental conditions and the complexity of surface water samples. The stability and test consistency of the instrument are not as good as those in the laboratory. Over time, response attenuation and sample injection pipeline blockage are prone to problems. It is necessary to regularly check the standard sample to track the instrument status, and automatically perform calibration, multi-point linearity and other quality control work when necessary to ensure the accuracy and stability of the monitoring data. In summary, the online water quality monitor for volatile organic compounds needs to be designed with supporting pre-treatment and intelligent quality control devices before it can be better used on site.

[0005] In the prior art: 1) If the protective measures are turned on when encountering high turbidity, and the instrument is not allowed to perform measurements, it will have a great impact on the data efficiency, so it cannot be used for flood season monitoring and water body monitoring with high turbidity all year round, which greatly limits the use scenarios. 2) The traditional filter element filtration method is easy to clog. Although there is backwashing, it does not take into account that when this filtration method encounters high turbidity water bodies in reality, the traditional multi-stage filtration mode will cause the pre-filter element to be clogged due to the filter element filtration volume limitation, and the amount of water sample required for subsequent testing cannot be obtained. 3) The surface of the filter element is not thoroughly rinsed. Due to the physical properties of the materials, traditional filter elements such as PP cotton and activated carbon cannot be backwashed at high pressure. If only the surface of the filter element is backwashed, the filter element cannot be thoroughly cleaned. 4) The personnel cost of daily quality control is high and remote quality control cannot be performed. The shelf life of volatile organic compound standards is very short. The standard requires that they be prepared on demand. Therefore, if daily quality control is to be performed every day, people need to be sent to the site every day to manually prepare samples, which increases the workload. Moreover, the surface water operation and maintenance regulations stipulate that daily quality control needs to be carried out between 6 and 7 am every day, and it is not realistic to require manual on-site preparation of standard samples in advance. The above reasons also make it impossible to perform remote quality control such as standard sample verification and multi-point calibration. 5) The traditional injection mode consumes a large amount of standard samples, and the volatile organic compound standard solution needs to be stored in a sealed manner at low temperature and away from light. The traditional injection mode requires rinsing with standard solution, which consumes a lot of water. Volatile organic compound standards, especially isotope standards, are relatively expensive. The traditional rinsing and then injection mode will greatly increase the operation and maintenance costs, and it is difficult to support remote quality control functions. Summary of the invention

[0006] In view of this, the present invention provides a bypass precision filtration pretreatment device, comprising: a sampling port, a filter element bracket, a backwash port, a water sample cup cover, a metal filter element, a water sample cup, an overflow pipe, a water inlet, and a drain port;

[0007] The filter element support is provided with a hollow pipe inside, an external thread in the middle, a sampling port and a backwash port at the top, and an internal thread at the bottom;

[0008] The metal filter element is connected to the internal thread at the bottom of the filter element bracket through the top external thread;

[0009] The sampling port and the backwash port are both connected to the upper part of the hollow pipe of the filter element support;

[0010] The backwash port is connected to the water vapor mixture through a pipeline;

[0011] The filter element bracket is connected to the internal thread of the water sample cup cover through the external thread in the middle;

[0012] The metal filter element is a hollow structure, with an external thread on the upper part connected to the internal thread at the bottom of the filter element bracket through the external thread, and the lower part is sunk into the water sample cup;

[0013] The water sample cup is sealed and connected to the water sample cup cover;

[0014] An overflow pipe, a water inlet and a drain are arranged in the water sample cup. The overflow pipe is used for liquid overflow. The water inlet and the drain are arranged at the bottom. The water inlet is used for water sample intake through a pipeline, and the drain is used for draining water sample through a pipeline.

[0015] In a specific embodiment of the present invention, the pore diameter of the metal filter element is 5 to 15 microns; the metal filter element is a stainless steel sintered filter element or a titanium-nickel alloy sintered filter element.

[0016] In a specific embodiment of the present invention, the internal volume of the metal filter element is 75 mL.

[0017] The present invention also provides a high turbidity water quality intelligent pretreatment system, comprising: a bypass precision filtration pretreatment device, a refrigerated precision sampling unit and an intelligent quality control device;

[0018] The refrigerated precision sample injection unit comprises: a refrigerated box 10, a ceramic plunger pump 11, an eight-way valve 12, a liquid storage ring 13, a three-way valve 14, a high-pressure nitrogen bottle 15, and a sample bottle 16.

[0019] The ceramic plunger pump 11 is connected to the normally open end of the three-way valve 14, the common end of the three-way valve is connected to the first end of the liquid storage ring, and the normally closed end of the three-way valve is connected to the high-pressure nitrogen bottle.

[0020] The liquid storage ring 13 contains pure water and the second end is connected to the common end of the eight-way valve.

[0021] The common end of the eight-way valve can be connected to other ports respectively by rotating the valve body: the first end is connected to the pure water bottle; the second end is connected to the mixing cup; the third end is connected to the detection unit; the fourth end is connected to the waste liquid bottle; the fifth end is connected to the air exhaust; the sixth end is the common end and is connected to the liquid storage ring; the seventh end is connected to the sample bottle, and the eighth end is connected to the bypass precision filtration pretreatment device.

[0022] The refrigerated precision sampling unit is respectively connected with the detection unit, the bypass precision filtration pretreatment device and the intelligent quality control device.

[0023] In a specific embodiment of the present invention, the sample bottle has a silicone rubber-polytetrafluoroethylene lined screw cap.

[0024] The device provided by the present invention can not only meet the normal measurement of water samples in a high turbidity environment, but also automatically perform various intelligent quality control measures such as standard sample verification, multi-point calibration, emergency quality control, etc. on the online volatile organic compound monitor, thereby ensuring the authenticity of the data, improving data efficiency, and reducing operation and maintenance costs. The system provided by the present invention can be applied on-site in unmanned surface water automatic monitoring stations for a long time to ensure the authenticity of water sample measurements and the accuracy of verification / calibration. The present invention mainly solves the problems of interference of high turbidity of surface water on measurement results / affecting data efficiency, poor storage of instrument standard samples, need for on-the-spot preparation, and large waste during sample injection, resulting in the inability of the instrument to perform unmanned intelligent quality control. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a diagram of a bypass precision filtration pretreatment device.

[0026] Among them, 1 is the sampling port, 2 is the filter element bracket, 3 is the backwash port, 4 is the water sample cup cover, 5 is the metal filter element, 6 is the water sample cup, 7 is the overflow pipe, 8 is the water inlet, and 9 is the drain outlet.

[0027] Figure 2 It is a schematic diagram of the refrigerated precision sampling unit.

[0028] Among them, 10 is a refrigerator, 11 is a ceramic plunger pump, 12 is an eight-way valve, 13 is a liquid storage ring, 14 is a three-way valve, 15 is a high-pressure nitrogen bottle, and 16 is a sample bottle with a silicone rubber-polytetrafluoroethylene liner screw cap. DETAILED DESCRIPTION

[0029] Example

[0030] The present invention designs a set of high turbidity water quality intelligent pretreatment system, which includes a bypass precision filtration pretreatment device, an intelligent quality control device and a refrigerated precision sampling unit. It can not only meet the normal measurement of water samples in a high turbidity environment, but also automatically perform standard sample verification, multi-point calibration, emergency quality control and other intelligent quality control measures on the online volatile organic compound monitor, thereby ensuring the authenticity of the data, improving data efficiency and reducing operation and maintenance costs.

[0031] The system provided by the present invention can be applied on-site in a long-term unattended surface water automatic monitoring station to ensure the authenticity of water sample measurement and the accuracy of verification / calibration.

[0032] The present invention mainly solves the problems that high turbidity of surface water interferes with the measurement results / affects data efficiency, instrument standard samples are difficult to preserve, need to be prepared on demand, and there is a lot of waste during sample injection, resulting in the inability of the instrument to perform unmanned intelligent quality control.

[0033] The intelligent quality control device is an instrument that uses an intelligent quality control sample preparation device to remotely command / automatically prepare standard samples such as standard verification samples and multi-point calibration samples, and after preparation, provide them to the monitoring instrument for testing corresponding quality control items.

[0034] The daily quality control is to conduct a standard sample check on the instrument every day, and determine the instrument performance through the indication error of the standard sample check result.

[0035] The high turbidity water quality intelligent pretreatment system comprises a bypass precision filtration pretreatment device, an intelligent quality control device and a refrigerated precision sampling unit.

[0036] The sampling port 1 of the bypass precision filtration pretreatment device is connected to the eighth port of the eight-way valve of the refrigerated precision sampling unit;

[0037] The third end of the eight-way valve of the refrigerated precision sampling unit is connected to the mixing cup of the intelligent quality control device;

[0038] The intelligent quality control device includes a mixing cup, a quantitative system, and a liquid power system; the mixing cup is used to configure a container for a standard sample of a required concentration; the quantitative system is used to accurately control the amount of liquid used; and the liquid power system is used to provide power and a delivery pipeline for the transfer of liquid between different containers.

[0039] The bypass precision filtration pretreatment device comprises: a sampling port, a filter element bracket, a backwash port, a water sample cup cover, a metal filter element, a water sample cup, an overflow pipe, a water inlet, and a drain outlet.

[0040] The filter element bracket is provided with a hollow pipe inside, an external thread in the middle, a sampling port and a backwash port on the top, and an internal thread at the bottom; the metal filter element is connected to the internal thread at the bottom of the filter element bracket through the top external thread; the sampling port and the backwash port are both connected to the upper part of the hollow pipe of the filter element bracket; the sampling port is connected to the sampling port of the precision sampling unit through a pipeline; the backwash port is connected to the water vapor mixture through a pipeline; the filter element bracket is connected to the internal thread of the water sample cup cover through the external thread in the middle; the metal filter element is a hollow structure, and the upper It is provided with an external thread and is connected to the internal thread at the bottom of the filter element bracket through the external thread, and the lower part is sunk into the water sample cup; the diameter of the metal filter element is 5 to 15 microns; the metal filter element is a stainless steel sintered filter element (or a titanium-nickel alloy sintered filter element) with an internal volume of 75mL; the water sample cup is sealed and connected to the water sample cup cover; an overflow pipe, a water inlet and a drain are provided in the water sample cup, the overflow pipe is used for liquid overflow, the water inlet and the drain are arranged at the bottom, the water inlet is used for water sample intake through a pipeline, and the drain is used for emptying the water sample through a pipeline.

[0041] The method for treating highly turbid water samples by the bypass precision filtration pretreatment device comprises the following steps:

[0042] First, graded sedimentation is used to remove easily settleable particles and primary sedimentation is performed to reduce large particles of sediment. The easily settleable turbidity water samples can usually be reduced to below 500NTU after sedimentation in the sedimentation tank.

[0043] Second, the water sample with easily settled particles removed enters the water sample cup through the water inlet. During the secondary sedimentation, the water sample is filtered from the outside to the inside of the metal filter element. After filtration, the turbidity of the water sample can be reduced from 500NTU to below 100NTU.

[0044] Third, the water sample passes through the sampling port and then passes through the refrigerated precision sampling unit to be supplied to the detection unit.

[0045] Fourth, after sampling is completed, discharge the water sample in the water sample cup through the drain port.

[0046] Fifth, inject the high-pressure water vapor mixture into the metal filter element through the backwash port, and clean the water sample cup while cleaning the filter element to achieve the purpose of thorough cleaning.

[0047] The intelligent quality control device includes: a mixing cup, a quantitative system, and a liquid power system. The sample preparation process of the intelligent quality control device is as follows:

[0048] The intelligent quality control device first calculates the required sample volume and the volume of pure water for dilution according to the required standard sample concentration, then accurately quantifies the required sample volume through the refrigerated precision sampling unit, injects the sample into the mixing cup of the intelligent quality control device, and then injects the required pure water quantified by the intelligent quality control device into the mixing cup for mixing.

[0049] The refrigerated precision sample injection unit is a sample injection unit with a constant temperature refrigeration function.

[0050] The refrigerated precision sample injection unit comprises: a refrigerated box, a ceramic plunger pump, an eight-way valve, a liquid storage ring, a three-way valve, a high-pressure nitrogen bottle, and a sample bottle with a silicone rubber-polytetrafluoroethylene liner screw cap.

[0051] The ceramic plunger pump is connected to the normally open end of the three-way valve, the common end of the three-way valve is connected to the first end of the liquid storage ring, the normally closed end of the three-way valve is connected to the high-pressure nitrogen bottle, a section of pure water is stored in the liquid storage ring for a long time and the second end is connected to the common end of the eight-way valve, and the common end of the eight-way valve can be connected to respectively through the rotating valve body: the pure water bottle at the first end; the mixing cup of the intelligent quality control device at the second end; the detection unit at the third end; the waste liquid bottle at the fourth end; the air exhaust at the fifth end; the common end at the sixth end; the sample bottle with a silicone rubber-polytetrafluoroethylene gasket screw cap at the seventh end; and the bypass precision filtration pretreatment device at the eighth end.

[0052] The sampling method of the refrigerated precision sampling unit comprises the following steps:

[0053] First, when quantitative measurement begins, first switch the common end of the eight-way valve to the pure water bottle at the first end of the eight-way valve, extract a certain amount of pure water, and use the pure water to clean the liquid storage ring. After cleaning, switch the common end of the eight-way valve to the waste liquid bottle at the fourth end of the eight-way valve and drain the cleaning water to the waste liquid, then switch to the air at the fifth end of the eight-way valve, and at the same time switch the three-way valve to the normally closed end and the common end, use high-pressure nitrogen to purge the liquid storage ring, and then empty it from the fifth end to ensure that there is no liquid residue.

[0054] Second, when the standard sample is quantified, the eight-way valve switches the common end to the empty connection with the fifth end of the eight-way valve to extract a certain amount of air, and then switches to the sample bottle with a silicone rubber-polytetrafluoroethylene liner screw cap at the seventh end of the eight-way valve, and then extracts the required amount of liquid to accurately quantify the standard sample.

[0055] Third, after the quantification is completed, the common end of the eight-way valve is switched to the mixing cup at the third end and liquid is injected into the mixing cup to dilute the sample.

[0056] The quantitative analysis of the refrigerated precision sampling unit ends here. The following is the process of quantitative analysis of pure water and diluted standard solution by the intelligent quality control device:

[0057] The intelligent quality control device uses a high-precision photoelectric quantitative system to quantify the required pure water, quickly (speed ≥ 25 ml / min) and accurately (repeatability ≤ 0.5%) prepare the required sample in the mixing cup, ensuring that the pure water and the sample do not interfere with each other. After the preparation is completed, the sample diluted to a specific concentration is supplied from the mixing cup to the subsequent detection unit (purge and capture) by the refrigerated precision sampling unit for measurement.

[0058] The solution of the present invention can effectively solve the following problems:

[0059] 1) Ensure that the filter element will not be blocked while obtaining sufficient filtered water samples. Experiments have shown that after enabling bypass precision pretreatment, the turbidity of water samples can be controlled below 100 NTU, and the particles in the water are all below 15 um, ensuring that the sample inlet pipeline will not be blocked.

[0060] 2) After each test, the filter element and sampling cup are automatically backwashed with a high-pressure water-gas mixture. In the case of high turbidity, the number of cleaning times will be automatically increased to ensure the cleaning effect.

[0061] 3) By using the sampling unit in the refrigerator, the waste of mother solution can be reduced and the consistency of the sample can be ensured. The standard solution can be used for a long time (>1 month) in the refrigerated precision sampling unit.

Claims

1. Bypass precision filtration pretreatment device, characterized in that: include: Sampling port, filter element bracket, backwash port, water sample cup cover, metal filter element, water sample cup, overflow pipe, water inlet, drain port; The filter element support is provided with a hollow pipe inside, an external thread in the middle, a sampling port and a backwash port at the top, and an internal thread at the bottom; The metal filter element is connected to the internal thread at the bottom of the filter element bracket through the top external thread; The sampling port and the backwash port are both connected to the upper part of the hollow pipe of the filter element support; The backwash port is connected to the water vapor mixture through a pipeline; The filter element bracket is connected to the internal thread of the water sample cup cover through the external thread in the middle; The metal filter element is a hollow structure, with an external thread on the upper part connected to the internal thread at the bottom of the filter element bracket through the external thread, and the lower part is sunk into the water sample cup; The water sample cup is sealed and connected to the water sample cup cover; An overflow pipe, a water inlet and a drain are arranged in the water sample cup. The overflow pipe is used for liquid overflow. The water inlet and the drain are arranged at the bottom. The water inlet is used for water sample intake through a pipeline, and the drain is used for draining water sample through a pipeline.

2. The bypass precision filtration pretreatment device according to claim 1, characterized in that: The pore diameter of the metal filter element is 5 to 15 microns; The metal filter element is a stainless steel sintered filter element or a titanium-nickel alloy sintered filter element.

3. The bypass precision filtration pretreatment device according to claim 2, characterized in that: The internal volume of the metal filter element is 75 mL.

4. High turbidity water quality intelligent pre-treatment system, characterized by: It includes the bypass precision filtration pretreatment device, the refrigerated precision sampling unit and the intelligent quality control device as described in claim 1; The refrigerated precision sample injection unit comprises: a refrigerated box, a ceramic plunger pump, an eight-way valve, a liquid storage ring, a three-way valve, a high-pressure nitrogen bottle, and a sample bottle; The intelligent quality control device includes a mixing cup, a quantitative system, and a liquid power system; the mixing cup is used to configure a container of a standard sample of a required concentration; the quantitative system is used to accurately control the amount of liquid used; and the liquid power system is used to provide power and a delivery pipeline for the transfer of liquids between different containers; The ceramic plunger pump is connected to the normally open end of the three-way valve. The common end of the three-way valve is connected to the first end of the liquid storage ring. The normally closed end of the three-way valve is connected to a high-pressure nitrogen bottle. The liquid storage ring contains pure water and the second end is connected to the common end of the eight-way valve. The common end of the eight-way valve can be connected to: the pure water bottle at the first end; the detection unit at the second end; the mixing cup at the third end; the waste liquid bottle at the fourth end; the drain at the fifth end; the common end at the sixth end; the sample bottle at the seventh end, and the bypass precision pretreatment device at the eighth end through a rotating valve body.

5. The high turbidity water quality intelligent pre-treatment system according to claim 4 is characterized in that: The sample vials had silicone-PTFE lined screw caps.

6. The method for treating highly turbid water samples using the bypass precision filtration pretreatment device according to any one of claims 1 to 3, characterized in that: The steps include: The water sample enters the water sample cup through the water inlet, and the water sample is filtered from the outside to the inside of the metal filter element.

7. The method for treating highly turbid water samples using the bypass precision filtration pretreatment device according to claim 6, characterized in that: Also includes: The water sample filtered into the metal filter element is supplied to the refrigerated precision sampling unit through the sampling port and then to the detection unit.

8. The method for treating highly turbid water samples using the bypass precision filtration pretreatment device according to claim 7, characterized in that: Also includes: The high-pressure water-vapor mixture is injected into the metal filter element through the backwash port.

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