A rapid dilution device for on-line analysis

Abstract

The present invention provides a rapid dilution device for on-line analysis, which includes a three-way solenoid valve group, a dilution cell, a sampling pipeline, a diluent pipeline and an air inlet pipeline; the three-way solenoid valve group includes a first three-way solenoid valve, a second three-way solenoid valve and a third three-way solenoid valve; the common end of the first three-way solenoid valve is connected to the common end of the second three-way solenoid valve through a first metering tube, and the normally open end of the second three-way solenoid valve is connected to the common end of the third three-way solenoid valve through a second metering tube; the sampling pipeline is connected to the normally closed end of the second three-way solenoid valve; the diluent pipeline is connected to the normally closed end of the third three-way solenoid valve; the air inlet pipeline is connected to the normally open end of the third three-way solenoid valve; the dilution cell is connected to the normally open end of the first three-way solenoid valve through a third metering tube. The dilution device of the present invention has a controllable dilution ratio and high quantitative accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of on-line analysis, and particularly relates to a rapid dilution device for on-line analysis. Background Art

[0002] In the prior art, on-line analyzers all have a certain detection range. When the concentration of the substance to be measured exceeds the detection upper limit of the analyzer, it is necessary to dilute the sample to dilute the sample concentration within the detection range of the on-line analyzer, and then perform detection.

[0003] Dilution operations usually introduce systematic errors. To obtain accurate test data, it is required that both the sample volume and the diluent volume in the dilution process be accurately quantified as much as possible. The quantification methods in the dilution process of on-line analyzers on the market are usually the following three: one is peristaltic pump quantification. According to the flow rate of the liquid pumped by the peristaltic pump and the running time, a certain proportion of the volume of the sample and the diluent are respectively added to the dilution pool, and then stirred evenly. Since the pump tube will deform over time, this method will cause the ratio of the sample and the diluent to change in the long term, resulting in a gradual deterioration of the dilution accuracy. To ensure the dilution effect, it is necessary to frequently calibrate the peristaltic pump quantification, and the operation and maintenance are complex. The second is syringe pump quantification. Syringe pump quantification is more accurate and stable than peristaltic pump quantification, but the running speed is low, and there is a problem that the syringe piston will leak air due to wear in the long-term use, resulting in a deterioration of the dilution accuracy. In addition, the cost of the syringe pump is often high. The third is peristaltic pump combined with photoelectric sensor quantification. The peristaltic pump only serves as a driving device for liquid flow, and the quantification is completed by a photoelectric sensor fixed at a specific position in the liquid flow path. This method has a high quantification accuracy, but the unit structure is relatively complex, the running speed is low, and for samples with high chromaticity or turbidity, there is a possibility that the photoelectric sensor cannot recognize or misjudge the liquid level. Therefore, for complex application scenarios, the reliability is low.

[0004] Based on this, the present invention provides a rapid dilution device for on-line analysis, which dilutes the sample by using a three-way solenoid valve and a metering tube, with few interference factors and accurate quantification. Summary of the Invention

[0005] The purpose of the present invention is to provide a rapid dilution device for on-line analysis, and the technical problem to be solved is the deficiency that the existing dilution device relies on a peristaltic pump for quantification, and the dilution ratio accuracy gradually deteriorates after long-term use.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] A rapid dilution device for on-line analysis includes a three-way solenoid valve group, a dilution pool, a sampling pipeline, a diluent pipeline, and an air inlet pipeline;

[0008] The three-way solenoid valve group includes a first three-way solenoid valve, a second three-way solenoid valve, and a third three-way solenoid valve; the common end of the first three-way solenoid valve is connected to the common end of the second three-way solenoid valve through a first metering tube, and the normally open end of the second three-way solenoid valve is connected to the common end of the third three-way solenoid valve through a second metering tube;

[0009] The sampling pipeline is connected to the normally closed end of the second three-way solenoid valve; the diluent pipeline is connected to the normally closed end of the third three-way solenoid valve; the air inlet pipeline is connected to the normally open end of the third three-way solenoid valve; the dilution tank is connected to the normally open end of the first three-way solenoid valve through a third metering tube.

[0010] The present invention can be improved as follows. A bubble sensor is provided on the third metering tube. The bubble sensor cooperates with the air inlet pipeline and the diluent pipeline to push the liquid, which helps to improve the metering accuracy.

[0011] The present invention can be further improved. It further includes a first waste liquid recovery pipeline, and the first waste liquid recovery pipeline is connected to the dilution tank.

[0012] Furthermore, it further includes a second waste liquid recovery pipeline, and the second waste liquid recovery pipeline is connected to the normally closed end of the first three-way solenoid valve.

[0013] In the present invention, a peristaltic pump is provided on the sampling pipeline, a peristaltic pump is provided on the diluent pipeline, and a peristaltic pump is provided on the air inlet pipeline.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) The rapid dilution device for on-line analysis of the present invention uses three-way solenoid valves and metering tubes for dilution, with a simple structure. It replaces the peristaltic pump metering in the prior art, the dilution ratio is controllable, and the metering accuracy completely depends on the selection of the metering tube, without relying on sensors, and has high accuracy.

[0016] (2) The rapid dilution device of the present invention is supplemented by a peristaltic pump to drive the liquid flow, and a bubble sensor (photoelectric sensor) is used to judge the liquid position. The peristaltic pump can drive the liquid flow at a relatively high operating speed, and quickly and efficiently complete the metering and transfer of the sample and the diluent. Since the peristaltic pump does not participate in metering and only drives the liquid flow, the metering accuracy is not affected by the change of the pump tube flow rate and is stable in the long term.

[0017] (3) The dilution ratio of the present invention depends on the selection of the metering tube, and there are various volume specifications for the metering tube. Therefore, the dilution ratio can be adjusted by replacing the metering tubes with different volumes. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of the rapid dilution device for on-line analysis of the present invention;

[0019] The reference numerals are as follows: 1 - the first three - way solenoid valve, 2 - the second three - way solenoid valve, 3 - the third three - way solenoid valve, 4 - the first metering tube, 5 - the second metering tube, 6 - the third metering tube, 7 - the sampling pipeline, 8 - the diluent pipeline, 9 - the intake pipeline, 10 - the first peristaltic pump, 11 - the second peristaltic pump, 12 - the third peristaltic pump, 13 - the fourth peristaltic pump, 14 - the first waste liquid recovery pipeline, 15 - the second waste liquid recovery pipeline, 16 - the dilution tank, 17 - the bubble sensor, 18 - the waste liquid collection bucket. Detailed implementation manners

[0020] The present invention will be further described below in conjunction with specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention.

[0021] Embodiment

[0022] As Figure 1 shown, a rapid dilution device for on - line analysis includes a three - way solenoid valve group, a dilution tank 16, a sampling pipeline 7, a diluent pipeline 8 and an intake pipeline 9.

[0023] The three - way solenoid valve group includes a first three - way solenoid valve 1, a second three - way solenoid valve 2 and a third three - way solenoid valve 3; the common end of the first three - way solenoid valve 1 is connected to the common end of the second three - way solenoid valve 2 through the first metering tube 4, and the normally open end of the second three - way solenoid valve 2 is connected to the common end of the third three - way solenoid valve 3 through the second metering tube 5.

[0024] The sample injection pipeline 7 is provided with a first peristaltic pump 10. One end of the sample injection pipeline 7 is connected to a sample, and the other end is connected to the normally closed end of the second three-way solenoid valve 2. When the first peristaltic pump 10 rotates counterclockwise, the sample can be transported to the three-way solenoid valve group; the diluent pipeline 8 is provided with a second peristaltic pump 11. One end of the diluent pipeline 8 is connected to a diluent, and the other end is connected to the normally closed end of the third three-way solenoid valve 3. When the second peristaltic pump 11 rotates counterclockwise, the diluent can be transported to the three-way solenoid valve group; the air inlet pipeline 9 is provided with a third peristaltic pump 12. One end of the air inlet pipeline 9 is communicated with air, and the other end is connected to the normally open end of the third three-way solenoid valve 3. When the third peristaltic pump 12 rotates counterclockwise, the air can be transported to the three-way solenoid valve group; the dilution tank 16 is provided with magnetic stirring, which can quickly mix different liquids evenly. It is connected to the normally open end of the first three-way solenoid valve 1 through the third metering tube 6, and a bubble sensor 17 is provided on the third metering tube 6. The bubble sensor 17 cooperates with the diluent pipeline 8 and the air inlet pipeline 9 to push the liquid, which helps to improve the metering accuracy. In the present invention, the pipe diameters and pipeline lengths of the first metering tube 4, the second metering tube 5 and the third metering tube 6 are determined according to the required metering volume, and the pipe diameters and pipe lengths of all other pipelines can be varied within a certain range. In addition, it should be clear that the metering volume of the diluent is actually composed of two parts, the second metering tube 5 and the third metering tube 6, and the first metering tube 4 is used to meter the sample. The internal volume ratio of "the second metering tube 5 + the third metering tube 6" to "the first metering tube 4" is the metering ratio of the diluent to the sample, that is, the dilution ratio.

[0025] The rapid dilution device for on-line analysis in this embodiment further includes a first waste liquid recovery pipeline 14 and a second waste liquid recovery pipeline 15. The first waste liquid recovery pipeline 14 is provided with a fourth peristaltic pump 13. One end of the first waste liquid recovery pipeline 14 is connected to the dilution tank 16, and the other end is connected to the waste liquid collection bucket 18. When the fourth peristaltic pump 13 rotates clockwise, the liquid in the dilution tank 16 can be emptied and transported to the waste liquid collection bucket 18. One end of the second waste liquid recovery pipeline 15 is connected to the normally closed end of the first three-way solenoid valve 1, and the other end is connected to the waste liquid collection bucket 18.

[0026] The method for diluting a sample using the above rapid dilution device for on-line analysis includes the following steps:

[0027] a. Cleaning the pipeline and metering the diluent: Open the third three-way solenoid valve 3, and the second peristaltic pump 11 rotates counterclockwise for a certain period of time (e.g., 10 seconds). The diluent passes through the diluent pipeline 8, the second peristaltic pump 11, the normally closed end of the third three-way solenoid valve 3, the common end of the third three-way solenoid valve 3, the second metering tube 5, the normally open end of the second three-way solenoid valve 2, the common end of the second three-way solenoid valve 2, the first metering tube 4, the common end of the first three-way solenoid valve 1, the normally open end of the first three-way solenoid valve 1, and the third metering tube 6 in sequence, and then enters the dilution tank 16. The liquid originally existing in the above pipeline is all pushed into the dilution tank 16 by the diluent. At the same time, the above pipeline includes the second metering tube 5 and the third metering tube 6, which are all filled with diluent, that is, the metering of the diluent has been completed simultaneously. Then close the third three-way solenoid valve 3.

[0028] b. Emptying the dilution tank 16: The fourth peristaltic pump 13 rotates clockwise for a certain period of time (e.g., 15 seconds). The liquid in the dilution tank 16 passes through the first waste liquid recovery pipeline 14 and the fourth peristaltic pump 13 in sequence, and then enters the waste liquid collection bucket 18. This step can also start synchronously with the previous step, but it needs to end a few seconds later than the previous step to completely empty the dilution tank 16.

[0029] c. Metering the sample: Open the first three-way solenoid valve 1 and the second three-way solenoid valve 2, and the first peristaltic pump 10 rotates counterclockwise for a certain period of time (e.g., 10 seconds). The sample passes through the sampling pipeline 7, the first peristaltic pump 10, the normally closed end of the second three-way solenoid valve 2, the common end of the second three-way solenoid valve 2, the first metering tube 4, the common end of the first three-way solenoid valve 1, the normally closed end of the first three-way solenoid valve 1, and the second waste liquid recovery pipeline 15 in sequence, and then enters the waste liquid collection bucket 18. Then close the first three-way solenoid valve 1 and the second three-way solenoid valve 2. At this time, the sample with the required metered volume has been retained in the first metering tube 4.

[0030] e. Mixing evenly: Two methods are available.

[0031] Method 1: The third peristaltic pump 12 rotates counterclockwise for a certain period of time (e.g., 15 seconds). The air passes through the air inlet pipeline 9, the third peristaltic pump 12, the normally open end of the third three-way solenoid valve 3, the common end of the third three-way solenoid valve 3, the second metering tube 5, the normally open end of the second three-way solenoid valve 2, the common end of the second three-way solenoid valve 2, the first metering tube 4, the common end of the first three-way solenoid valve 1, the normally open end of the first three-way solenoid valve 1, and the third metering tube 6 in sequence, and then enters the dilution tank 16. The sample in the first metering tube 4 and the diluent in the second metering tube 5 and the third metering tube 6 are all pushed into the dilution tank 16 by the air, and then are stirred evenly in the dilution tank 16 by electromagnetic stirring.

[0032] In the second method, the third peristaltic pump 12 rotates counterclockwise for a certain period of time (such as 2 seconds). The air passes through the intake pipe 9, the third peristaltic pump 12, the normally open end of the third three-way solenoid valve 3, and the common end of the third three-way solenoid valve 3 in sequence. At this time, a small section of air enters the second metering tube 5, and pushes the diluent in the second metering tube 5 and the third metering tube 6, as well as the sample in the first metering tube 4, a short distance in the direction of the dilution tank 16. Then, the third three-way solenoid valve 3 is opened, and the second peristaltic pump 11 rotates counterclockwise. At the same time, the bubble sensor 17 starts to monitor whether an air section appears at the end of the third metering tube 6. The diluent passes through the diluent pipe 8, the second peristaltic pump 11, the normally closed end of the third three-way solenoid valve 3, the common end of the third three-way solenoid valve 3, the second metering tube 5, the normally open end of the second three-way solenoid valve 2, the common end of the second three-way solenoid valve 2, the first metering tube 4, the common end of the first three-way solenoid valve 1, the normally open end of the first three-way solenoid valve 1, and the third metering tube 6 in sequence, and pushes the diluent in the second metering tube 5 and the third metering tube 6, the sample in the first metering tube 4, and a small section of air brought in by the previous action in the direction of the dilution tank 16. When the bubble sensor 17 monitors that an air section continuously appears at the end of the third metering tube 6 (such as continuously for 1 second), the second peristaltic pump 11 stops operating. At this time, the diluent in the second metering tube 5 and the third metering tube 6, as well as the sample in the first metering tube 4, have all entered the dilution tank 16, and are then stirred evenly under the action of magnetic stirring. Finally, the third three-way solenoid valve 3 is closed.

[0033] The above-mentioned first method is driven by pure air, and the second method is driven by the combination of an air section and diluent. Since it is a small section of air rather than a large section of air in the first method that drives the sample and diluent into the dilution tank 16 in the second method, the pipeline residue is smaller, so the dilution accuracy will be higher.

[0034] The above embodiments have elaborated in detail different implementation processes of the present invention. However, the implementation manners of the present invention are not limited thereto. Those of ordinary skill in the art can achieve the purpose of the present invention based on the content disclosed in the present invention. Any improvements and deformations made based on the concept of the present invention fall within the protection scope of the present invention. The specific protection scope is subject to what is recorded in the claims.

Claims

1. A rapid dilution device for on-line analysis, characterized in that It includes a three-way solenoid valve group, a dilution tank (16), a sample injection pipeline (7), a diluent pipeline (8), and an air inlet pipeline (9); The three-way solenoid valve group includes a first three-way solenoid valve (1), a second three-way solenoid valve (2), and a third three-way solenoid valve (3); the common end of the first three-way solenoid valve (1) is connected to the common end of the second three-way solenoid valve (2) through a first metering tube (4), and the normally open end of the second three-way solenoid valve (2) is connected to the common end of the third three-way solenoid valve (3) through a second metering tube (5); The first metering tube (4) is used for quantifying the sample, and the second metering tube (5) and the third metering tube (6) are used for quantifying the diluent; The sample injection pipeline (7) is connected to the normally closed end of the second three-way solenoid valve (2); the diluent pipeline (8) is connected to the normally closed end of the third three-way solenoid valve (3); the air inlet pipeline (9) is connected to the normally open end of the third three-way solenoid valve (3); the dilution tank (16) is connected to the normally open end of the first three-way solenoid valve (1) through a third metering tube (6); The sample injection pipeline (7) is provided with a peristaltic pump, the diluent pipeline (8) is provided with a peristaltic pump, and the air inlet pipeline (9) is provided with a peristaltic pump; The peristaltic pump of the air inlet pipeline (9) is used to push a small section of air into the second metering tube (5) to propel the liquid after the quantification of the first metering tube (4), the second metering tube (5), and the third metering tube (6) is completed; the peristaltic pump of the diluent pipeline (8) is used to push the diluent into the second metering tube (5) to propel a small section of air after the air inlet pipeline (9) pushes a small section of air into the second metering tube (5), and the volume of the small section of air is less than the total volume of the first metering tube (4), the second metering tube (5), and the third metering tube (6); A bubble sensor (17) is provided at the end of the third metering tube (6), and the bubble sensor (17) monitors whether a small section of air appears and is used to cooperate with the diluent pipeline (8) and the air inlet pipeline (9) to propel the liquid.

2. The rapid dilution device for on-line analysis according to claim 1, characterized in that, It also includes a first waste liquid recovery pipeline (14), and the first waste liquid recovery pipeline (14) is connected to the dilution tank (16).

3. The rapid dilution device for on-line analysis according to claim 2, characterized in that, It also includes a second waste liquid recovery pipeline (15), and the second waste liquid recovery pipeline (15) is connected to the normally closed end of the first three-way solenoid valve (1).

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