CN106872225A - A kind of water sample pretreatment device and its application method - Google Patents

Abstract

The invention provides a kind of water sample pretreatment device and its application method, the device is made up of the part such as lid, sealing ring, collecting pit, liquid level sensor, water outlet on-off valve, drainpipe, two five mouthfuls of switching valves and air pump on water inlet on-off valve, water inlet pipe, tracheae, temperature sensor, pressure sensor, collecting pit.By controlling the folding of valve, an air pump realizes that collecting pit switches circulation between the state of drawing water and hull-borne, and iterative cycles are to complete water sample with bulk mass product pre-treatment, while water sample pre-treatment major parameter is measured, and with functions such as filter membrane replacing promptings.Simple structure of the present invention, technology maturation, a large amount of cumbersome artificial operations are eliminated, be particularly well-suited to ambient water sample filtering enrichment pretreatment process.

Description

A kind of water sample pretreatment device and using method thereof

technical field

The invention belongs to the field of analysis of target pollutants in environmental water samples, and mainly relates to the analysis pretreatment of organic pollutants in environmental water such as rivers, lakes, oceans, and discharge water, especially those involved in laboratory water sample filtration and enrichment treatment analysis processes A water sample pretreatment system and its application method.

Background technique

Trace organic pollutants in environmental water, especially polycyclic aromatic hydrocarbons, polychlorinated biphenyls and organochlorine pesticides, although the absolute content is very low, due to their persistence, bioaccumulation and long-distance transport characteristics have attracted widespread attention.

In order to adapt to various analysis methods, such as GC, LC, HPLC-MS, GC/MS, etc., it is often necessary to collect a large number of water samples to the laboratory for extraction and concentration. This not only has a large workload, but also has a series of unfavorable factors. The problem of transporting large-volume samples is that chemical changes and adsorption losses on the surface of the container may occur. In addition, it is expected that continuous sampling of the water system will yield a more representative sample than periodic sampling. Therefore, analysts hope to effectively eliminate these unfavorable factors in order to improve the quality of analysis.

Generally speaking, the time-consuming process of sample pretreatment accounts for more than 60% of the entire analysis process, and sample pretreatment is the focus of trace analysis. At present, the pretreatment methods with relatively mature technology development, high extraction efficiency and the use of more trace organic pollutants in water include solid phase extraction (solid phase extraction, SPE) and solid phase micro-extraction (solid phase micro-extraction, SPM). E), membrane extraction (membrane extraction), semi-permeable membrane passive sampling device (semi-permeable membrane devices, SPMD), etc. Generally, the total volume of filtered water samples is 20L or even more than 50L, and the flow rate of water samples through the filter membrane and extraction column is low. When using the traditional suction filter bottle experimental system to filter water samples, manual operation is required every few minutes to pour out the waste water or It often takes more than ten or dozens of hours to replace the suction filter bottle and prepare a concentrated sample, which is time-consuming and labor-intensive.

Therefore, the device of the present invention and its method of use are proposed. Driven by the water sample pretreatment device of the present invention, the collected water samples form a continuous filtration flow path: after the water sample is filtered through a filter membrane or enriched by a solid-phase extraction column, it flows into the Metering and control device, this device measures and controls the main parameters in the water sample filtration process, and can realize automatic and stable filtration process through computer control.

Contents of the invention

The technical problem solved by the invention is to provide a method and device for measuring and controlling parameters of water sample pretreatment. The invention belongs to the field of analysis of target pollutants in water samples, and mainly relates to the analysis pretreatment of organic pollutants in environmental water such as rivers, lakes, oceans, and discharge water, especially a process related to laboratory water sample filtration and enrichment treatment analysis processes. A water sample pretreatment device and a method for using the same.

A water sample pretreatment parameter measurement and control system proposed by the present invention, the main components include water inlet on-off valve, water inlet pipe, air pipe, temperature sensor, pressure sensor, collection pool cover, sealing ring, collection pool, liquid level Sensor, water outlet on-off valve, drain pipe, two-position five-port switching valve, air pump and other components; the upper cover of the collection pool, the sealing ring cooperate with the collection pool to form a closed space inside the collection pool; water inlet pipe, air pipe, temperature Sensors and pressure sensors are installed and fixed on the upper cover of the collection tank; a liquid level sensor is installed on the side wall of the collection tank; a water on-off valve and a drain pipe are installed on the bottom of the collection tank, and the water on-off valve is normally closed when it is not powered; The upper cover of the collection tank is connected with the two-position five-port switch valve through the air pipe, so that the air path in the inner space of the collection tank communicates with the P port of the two-position five-port switch valve.

The bottom of the water inlet pipe is an oblique cut, which is installed on the upper cover of the collection tank. After being fixed, the cut of the water inlet pipe is in contact with the inner wall of the collection tank, and the water flow slowly flows into the inner space of the collection tank along the inner wall of the collection tank.

The temperature sensor is a slender thermal resistance or thermocouple, which is installed on the upper cover of the collection pool, and after being fixed, the lower part extends into the inner space of the collection pool to detect the temperature of the water sample.

The pressure sensor is a pressure sensor with a data signal output, which is used to detect the air pressure in the inner space of the collection tank.

The collection tank is made of stainless steel, plexiglass and other materials. The inner wall is smooth and the bottom is conical.

The liquid level sensor is a continuous liquid level sensor fixed on the side of the collection tank, which is used to detect the height of the water samples collected in the collection tank. Through calculation, the parameters such as the total volume and average flow rate of the filtered water samples can be obtained.

The two-position five-port switching valve has five air ports A, B, R, P, and S, and the A port is connected to the air pump inlet through the pipeline; the B port of the two-position five-port switching valve is connected to the air pump outlet through the pipeline The P port of the two-position five-port switching valve is connected to the internal space of the collection tank through the air pipe; the two-position five-port switching valve is in the default state. It communicates with port S, and the air pump pumps air into the internal space of the collection tank; in the state of power on, the internal pipeline P port of the two-position five-port switching valve communicates with port B, and port A communicates with port R, and the air pump blows air into the internal space of the collection tank .

A method for using a system for measuring and controlling water sample pretreatment parameters. By controlling the state of an air pump and a valve, the water sample can be measured at a slow flow rate, and the water sample can be automatically collected and drained within a certain volume, and the water sample can be monitored. The real-time temperature, average flow rate, and total volume of filtration.

The working state of the flow control system has two states: pumping and draining: in the pumping state, the internal pipeline of the water inlet on-off valve is opened, the internal pipeline of the outlet water on-off valve is closed, the two-position five-port switching valve is closed, and the internal pipeline P The port is connected to the A port, and the B port is connected to the S port. The air pump pumps air to the inner space of the collection tank, forming a negative pressure water sample enters the collection tank and collects; when the liquid level of the water sample detected by the liquid level sensor reaches the set upper limit , the system control switches to the drainage state, the internal pipeline of the water inlet on-off valve is closed, the internal pipeline of the outlet water on-off valve is opened, and the two-position five-port switching valve is opened. The P port of the internal pipeline is connected to the B port, and the A port is connected to the R port. The air pump blows air to the inner space of the collection tank to form a positive pressure. After switching the on-off valve, the water sample is discharged from the bottom of the collection tank; when the liquid level of the water sample detected by the liquid level sensor reaches the set lower limit or passes the set After a certain period of time, the system switches to the pumping state, and the total accumulation of filtered water samples is added once; the cycle is repeated to complete the pretreatment of large-volume water samples.

In a cycle of pumping and draining, the system records the filtration time and the effective volume of the initially calibrated collection tank, and converts the average water flow rate in a single cycle.

The system has filter clogging and replacement reminder functions. The system sets the alarm pressure limit value based on experience. When the pressure value of the pressure sensor exceeds the alarm pressure limit value, the system sends a signal to remind the user to replace the filter membrane.

The beneficial effects of the present invention are: the water sample pretreatment parameter measurement and control system proposed by the present invention replaces the cumbersome manual operation of concentrating and preparing water samples by traditional methods such as laboratory suction bottles; it is convenient for automatic program control to realize the water flow path and complete After the water sample is filtered and enriched, parameters such as filtered water temperature, average water flow velocity, and total filtered water volume are automatically measured; by monitoring the air pressure in the collection pool, functions such as an alarm for filter membrane clogging can be realized. The invention has simple structure and mature technology, and is especially suitable for the process of sample preparation in the pretreatment of large-volume environmental water analysis.

Description of drawings

Fig. 1 is a schematic connection diagram of the system for measuring and controlling water sample pretreatment parameters in the water sample preparation process of the present invention. After the collected large volume of water is filtered through the filter membrane and enriched by the enrichment unit, the water flows into the system for measuring and controlling the water sample pretreatment parameters of the present invention;

Fig. 2 is the schematic diagram of the system of water sample pretreatment parameter measurement and control of the present invention;

Among them, 1 is the water inlet on-off valve; 2 is the water inlet pipe; 3 is the air pipe, 4 is the temperature sensor, 5 is the pressure sensor, 6 is the upper cover of the collection tank, 7 is the sealing ring, 8 is the collection tank, and 9 is the liquid level sensor , 10 is the water outlet on-off valve, 11 is the drain pipe, 12 is the two-position five-port switching valve, and 13 is the air pump;

Fig. 3 is a flow chart of water sample preparation process;

Fig. 4 is a schematic diagram of pumping state;

Fig. 5 is a schematic diagram of the drainage state.

detailed description

A water sample pretreatment device proposed by the present invention includes a water inlet on-off valve, a water inlet pipe, a gas pipe, a temperature sensor, a pressure sensor, a collection tank cover, a sealing ring, a collection tank, a liquid level sensor, an outlet water on-off valve, a drainage Pipe, two-position five-port switching valve, air pump and other components; the upper cover of the collection tank, the sealing ring and the collection tank cooperate to form a closed space inside the collection tank; the water inlet pipe, air pipe, temperature sensor, and pressure sensor are installed and fixed on the collection tank. The tank is covered; a liquid level sensor is installed on the side wall of the collection tank; a water outlet on-off valve and a drain pipe are installed at the bottom of the collection tank, and the water outlet on-off valve is in a normally closed state when it is not powered; the upper cover of the collection tank is connected to the two The one-position five-port switching valves are connected to each other, so that the gas path in the inner space of the collection tank communicates with the P port of the two-position five-port switching valves.

The bottom of the water inlet pipe is an oblique cut, which is installed on the upper cover of the collection tank. After being fixed, the cut of the water inlet pipe is in contact with the inner wall of the collection tank, and the water flow slowly flows into the inner space of the collection tank along the inner wall of the collection tank.

The temperature sensor is a slender thermal resistance or thermocouple, which is installed on the upper cover of the collection pool, and after being fixed, the lower part extends into the inner space of the collection pool to detect the temperature of the water sample.

The pressure sensor is a pressure sensor with a data signal output, which is used to detect the air pressure in the inner space of the collection tank.

The collection tank is made of plexiglass and other materials. The inner wall is smooth and the bottom is conical.

The liquid level sensor is a continuous liquid level sensor fixed on the side of the collection tank, which is used to detect the height of the water samples collected in the collection tank. Through calculation, the parameters such as the total volume and average flow rate of the filtered water samples can be obtained.

The two-position five-port switching valve has five air ports A, B, R, P, and S, and the A port is connected to the air pump inlet through the pipeline; the B port of the two-position five-port switching valve is connected to the air pump outlet through the pipeline The P port of the two-position five-port switching valve is connected to the internal space of the collection tank through the air pipe; the two-position five-port switching valve is in the default state. It communicates with port S, and the air pump pumps air into the internal space of the collection tank; in the state of power on, the internal pipeline P port of the two-position five-port switching valve communicates with port B, and port A communicates with port R, and the air pump blows air into the internal space of the collection tank .

The following is an illustration of the specific implementation of this patent, and the specific steps are:

1) Collect 20L of environmental water samples such as rivers and lakes, and connect the pipeline to the system of the present invention after passing through the filter membrane and the enrichment unit.

2) Under program control, start the air pump, open the internal pipeline of the water inlet on-off valve 1, close the internal pipeline of the water outlet on-off valve 10, close the two-position five-port switching valve 12, and connect the P port and the A port of the internal pipeline. Port B communicates with port S, and the air pump pumps air into the inner space of the collection tank 8 to form a negative pressure water sample that enters the collection tank and collects.

3) After a period of time (such as 20s), when the liquid level of the water sample detected by the liquid level sensor 9 reaches the set upper limit value, under program control, the system control switches to the drain state, and the internal pipe of the water inlet on-off valve 1 The circuit is closed, the internal pipeline of the water outlet on-off valve 10 is opened, and the two-position five-port switching valve 12 is opened. The P port of the internal pipeline communicates with the B port, and the A port communicates with the R port. The air pump 13 blows air to the internal space of the collection tank 8. Positive pressure is formed, and after switching the on-off valve, the water sample is discharged from the bottom of the collection tank 8 .

4) When the water is discharged to the lower limit set by the liquid level sensor, under program control, the system switches to the pumping state, and the total accumulation of filtered water samples is added once;

5) Repeat steps 2-4 above until the air pressure monitored by the system is lower than the empirically set pressure (such as -20Kpa), and the program will give an alarm for filter membrane clogging, prompting the operator to replace the filter membrane;

6) After the replacement, continue until the total volume of filtered water reaches 20L, collect the filter membrane and enrichment unit as the prepared concentrated water sample, and send it to the next step of the pollutant analysis process.

Claims (10)

1. a kind of water sample pretreatment device, it is characterised in that：Part include water inlet on-off valve (1), On water inlet pipe (2), tracheae (3), temperature sensor (4), pressure sensor (5), collecting pit cover (6), Sealing ring (7), collecting pit (8), liquid level sensor (9), water outlet on-off valve (10), drainpipe (11), Two five mouthfuls of switching valves (12) and air pump (13)；

Collecting pit (8) is the container of upper end open, and container open end is provided with lid (6) on collecting pit, receives (6) are covered on Ji Chi sealing ring (7) is provided with and between container open end；On described collecting pit cover (6), Sealing ring (7) coordinates the space for collecting pit is internally formed closing with collecting pit (8)；

Water inlet pipe (2), tracheae (3), temperature sensor (4), pressure sensor (5) are installed and fixed In covered on collecting pit on (6) and respectively with collecting pit (8) intracavity inter-connection, water inlet pipe sets on (2) Have into water on-off valve (1)；In collecting pit (8) side, wall is provided with for monitoring collecting pit (8) interior liquid The liquid level sensor (9) of height；Drainpipe (11), drainpipe (11) are installed in collecting pit (8) bottom Water outlet on-off valve (10) is provided with, normal off status is in when water outlet on-off valve (10) is not powered on；Tracheae (3) it is connected with a port of two five mouthfuls of switching valves (12) away from one end that (6) are covered on collecting pit It is logical, collecting pit (8) inner chamber is connected with two five mouthfuls of switching valves (12) by tracheae (3), make Collecting pit (8) inner space gas circuit is obtained to be communicated with two P mouthfuls of five mouthfuls of switching valves (12).

2. device as claimed in claim 1, it is characterised in that：Water inlet pipe (2) outlet at bottom is wedge Shape angular cut, is installed on collecting pit and covers on (6), coordinates the otch of water inlet pipe (2) and receipts after fixing Ji Chi (8) inwall is contacted, and it is internal that current slowly flow into collecting pit (8) along collecting pit (8) inwall Space.

3. device as claimed in claim 1, it is characterised in that：Temperature sensor (4) is elongated Thermal resistance or thermocouple, are installed on collecting pit and cover on (6), coordinate fixed rear lower to extend into collection Pond (8) inner space, is used to detect the temperature of water sample；

Described pressure sensor (5), the pressure sensor with data-signal output, is used to detect receipts The air pressure of Ji Chi (8) inner space.

4. device as claimed in claim 1, it is characterised in that：Collecting pit (8) is by stainless steel or has The materials such as machine glass are processed, and inner wall smooth, bottom is tapered, and the water for collecting can be smooth along inwall Flow through water outlet on-off valve (10), drainpipe (11) and discharge collecting pit.

5. device as claimed in claim 1, it is characterised in that：Liquid level sensor (9) is affixed to A kind of continuous liquid level sensor of collecting pit (8) side, is used to detect the water collected in collecting pit (8) The height of sample, by the cumulative volume, the mean flow rate that calculate the water sample that can draw filtering.

6. device as claimed in claim 1, it is characterised in that：Two five mouthfuls of switching valves (12) tools There are five gas ports of A, B, R, P, S, A mouthfuls is connected by pipeline with air pump (13) air inlet (13a) It is logical；Two B mouthfuls of five mouthfuls of switching valves (12) passes through pipeline and air pump (13) gas outlet (13b) phase Connection；Two P mouthfuls of five mouthfuls of switching valves (12) empty with the inside of collecting pit (8) by tracheae (3) Between be connected；

Two five mouthfuls of switching valves (12), two five mouthfuls of switching valve (12) internal duct P by default Mouth is communicated with A mouthfuls, and B mouthfuls communicates with S mouthfuls, and air pump (13) is evacuated to collecting pit (8) inner space； In the energized state, two five mouthfuls of P mouthfuls of switching valve (12) internal ducts are communicated with B mouthfuls, A mouthfuls and R Mouth is communicated, and air pump (13) is to collecting pit (8) inner space air-blowing.

7. a kind of application method of any water sample pretreatment devices of claim 1-6, it is characterised in that： By controlling air pump and valve state, realize that the water sample in a constant volume is collected and draining automatically, And monitor real time temperature, mean flow rate, the filtering cumulative volume of water sample.

8. application method as claimed in claim 7, it is characterised in that：Working state of system draws water With 2 kinds of states of draining：

Draw water under state, water inlet on-off valve (1) internal duct is opened, water outlet on-off valve (10) is internal Pipeline is closed, two five mouthfuls of switching valves (12) are closed, and internal duct P mouthful communicates with A mouthfuls, B mouthfuls and S mouthfuls communicates, and air pump is evacuated to collecting pit (8) inner space, forms negative pressure water sample and enters collecting pit simultaneously Collect；When the water sample liquid level of liquid level sensor (9) detection reaches the higher limit of setting, system control System switches to hull-borne, and water inlet on-off valve (1) internal duct is closed, water outlet on-off valve (10) is interior Portion's pipeline is opened, two five mouthfuls of switching valves (12) are opened, and internal duct P mouthfuls communicates with B mouthfuls, A mouthfuls Communicated with R mouthfuls, air pump (13) forms malleation to collecting pit (8) inner space air-blowing, and switching is logical After disconnected valve, water sample is discharged from collecting pit (8) bottom；When the water sample of liquid level sensor (9) detection Liquid level reaches the lower limit of setting or by after a period of time for setting, system switches to the state of drawing water, mistake The water sample cumulative volume of filter is cumulative 1 time；Iterative cycles are completing water sample with bulk mass product pre-treatment.

9. water sample pre-treatment parameter metrology as claimed in claim 7 or 8 and the system of control make With method, it is characterised in that draw water with one cycle period of draining, the system record filtering time and The dischargeable capacity of the collecting pit of initial alignment, the average current velocity in the conversion single cycle cycle.

10. application method as claimed in claim 7 or 8, it is characterised in that：The system has filter membrane Block, change prompting function, system rule of thumb sets alarm pressure limiting value, when pressure sensor Pressure value exceedes alarm pressure limiting value, and system sends signal and reminds user to change filter membrane.