Device for rapidly measuring furfural in transformer oil

Abstract

The utility model relates to the field of furfural determination, in particular to a device for rapidly determining furfural in transformer oil. The device is provided with a waste liquid port and an air inlet, and comprises an injection assembly, a selector valve, a sample tube, a standard oil sample container, an eluent container, an extract container, a sample injection valve, a chromatographic column, a column oven, an LED detector, an on-line filter and a battery, the selector valve is provided with a common port and eight selection ports which are selected to be independently communicated with the common port through adjustment. The injection assembly comprises a high-pressure injection pump and a buffer ring, and the high-pressure injection pump, the buffer ring and a common port of the selector valve are sequentially communicated; the sample injection valve is a two-position six-way valve, is provided with six ports and two phases, and is internally provided with a quantitative loop; the on-line filter is communicated with the sample injection valve; a chromatographic column communicated with the sample injection valve is arranged in the column oven, and the column oven is provided with a heating sheet for heating and a thermocouple for detecting temperature; and the LED detector is communicated with the chromatographic column. The device has the advantages of high integration level, light weight, automatic measurement, labor cost saving and redundancy waste avoiding.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of furfural determination, especially a kind of rapid determination device of furfural in transformer oil. BACKGROUND

[0002] Transformer oil furfural test is the test for detecting the furfural content in oil-immersed transformer oil in the power industry. Furfural content is an important indicator for evaluating the quality of transformer oil. Furfural is generated by the decomposition of transformer oil under the conditions of high temperature, high voltage and high water content, which has a negative impact on the electrical properties of oil, so its content must be controlled within a certain range. Generally speaking, it is recommended to conduct transformer oil furfural test once a year; for transformers used normally, the test can be conducted once every other year or longer.

[0003] Currently, the power industry mainly uses industry standards to determine the furfural in transformer oil, using a liquid chromatograph and the liquid chromatography method for determining the furfural content in transformer oil according to the industry standard DL / T 1355-2014. The specific experimental procedure is to extract the transformer oil with methanol manually, filter the methanol layer obtained after suction extraction to obtain a test sample. The test sample is injected into the liquid chromatography system, and the sample is eluted with an appropriate proportion of organic solvent. The effluent is measured for ultraviolet absorption at 277 nm, and the peak time under the same conditions is compared with that of a known concentration of furfural standard solution for qualitative analysis; the peak areas of the two are compared for quantitative analysis. The liquid chromatography system is composed of a liquid pump, a sample injector and a detector. After the sample is injected into the chromatographic column, the eluent delivered by the liquid pump washes different substances from the inlet of the chromatographic column to the outlet of the chromatographic column. Different compounds are separated according to their different moving speeds and produce absorbance signals on the detector, and the compounds can be quantitatively analyzed according to the intensity of the absorbance signals.

[0004] However, the above-mentioned prior art has the following disadvantages:

[0005] 1. The volume and weight of the conventional liquid chromatograph are not suitable for mobile measurement. A general liquid chromatograph is composed of 3-6 different modules, and weighs dozens or even hundreds of kilograms, so it cannot be moved and the sample cannot be measured on site.

[0006] 2. A large number of professionals are needed for laboratory determination. According to the liquid chromatography method for determining the furfural content in transformer oil in DL / T 1355-2014, the transformer oil sample needs to go through several steps such as methanol extraction, sample filtration and chromatographic analysis. The operator needs to have basic chemical experiment training. This also brings inconvenience to the measurement of the project and increases the labor cost.

[0007] 3. Dedicated liquid chromatography is generally designed for the general determination of non-specific target compounds, but there is a lot of redundancy for the specialized furfural analysis needs, which results in a large amount of waste in equipment configuration. Utility Model Content

[0008] The purpose of the utility model is to address the problems existing in the background technology and propose a rapid determination device for furfural in transformer oil. The device integrates the multi-step functions of automatic sample pre-extraction, automatic filtration, automatic sampling, automatic chromatographic elution and quantification in one device. The whole device is light in weight, can realize mobile work and on-site analysis, and automatically determines the whole process, saving labor costs. The overall structure is simple and avoids redundancy and waste.

[0009] The technical solution of the utility model is a device for rapid determination of furfural in transformer oil, which has a waste liquid port and an air inlet, comprises an injection assembly, a selection valve, a sample tube, a standard oil sample container, an eluent container, an extract container, an injection valve, a chromatographic column, a column oven, an LED detector, an online filter and a battery; the selection valve has a common port and eight selection ports which are selected by adjustment to be individually connected to the common interface; the injection assembly comprises a high-pressure injection pump and a buffer ring, and the high-pressure injection pump, the buffer ring and the common port of the selection valve are connected in sequence; the injection valve is a two-position six-way valve, has six ports, has two phases, and a built-in quantitative loop; the online filter is connected to the injection valve; the column oven is equipped with a chromatographic column connected to the injection valve, and has a heating plate for heating and a thermocouple for detecting temperature; the LED detector is connected to the chromatographic column; the battery is used for power supply; the eluent container, the extract container, the standard oil sample container, the sample tube, the air inlet, the waste liquid port, the online filter and the injection valve are respectively connected to the eight selection ports of the selection valve.

[0010] Preferably, the buffer ring is a section of inert pipeline with an internal volume consistent with the range of the high-pressure injection pump.

[0011] Preferably, the selection valve includes a first valve body, a first stator located inside the first valve body, and a first rotor rotating on the outer periphery of the first stator. The first rotor has a slot, and a common port and eight selection ports are all located on the first valve body. When one of the slots is directed toward a selection port, the selection port is connected to the common port.

[0012] Preferably, the injection valve includes a second valve body, a second stator located in the second valve body, and a second rotor rotating around the outer periphery of the second stator.

[0013] Preferably, the selection valve and the injection valve are both made of stainless steel or polyetheretherketone.

[0014] Preferably, the device further comprises a sample base for placing the sample tube and a vibration motor arranged on the sample base.

[0015] Compared with the prior art, the device has the following beneficial technical effects:

[0016] The device is simplified and successfully combined with the functions of automatic pre-extraction, automatic filtration, automatic sample injection, automatic chromatographic elution and quantitative multi-step functions. The above equipment is integrated on a small-sized machine body with a total weight of about 10kg, the device can easily realize mobile work and on-site analysis, and can automatically perform the analysis of transformer oil samples and the self-cleaning step. The measured results are compared with the measured results of the built-in standard oil sample, and the measurement results are automatically obtained, manual operation is saved, and the determination operation is simple. The device combines the metering pump at different positions of the automatic sample injection module and the infusion module in the general liquid chromatograph, and adopts the simplest structure to realize the infusion of the single metering pump to the whole process. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The structure of the embodiment of the utility model is shown.

[0018] Reference signs: 1, high-pressure injection pump; 2, buffer ring; 3, selection valve; 4, sample tube; 5, sample base; 6, vibration motor; 7, standard oil sample container; 8, eluent container; 9, extraction liquid container; 10, sample valve; 11, chromatographic column; 12, column oven; 13, LED detector; 14, online filter; 15, battery; 16, data system. DETAILED DESCRIPTION

[0019] As Figure 1 shown, the device for rapidly measuring furfural in transformer oil provided by the embodiment has a waste liquid port and an air inlet, and comprises a high-pressure injection pump 1, a buffer ring 2, a selection valve 3, a sample tube 4, a sample base 5, a vibration motor 6, a standard oil sample container 7, an eluent container 8, an extraction liquid container 9, a sample valve 10, a chromatographic column 11, a column oven 12, an LED detector 13, an online filter 14 and a battery 15, and a data system 16 is additionally provided to control and analyze the whole measuring device.

[0020] The selection valve 3 has one common port and eight selection ports which are individually communicated with the common port by adjusting. The selection valve 3 comprises a first valve body, a first stator located inside the first valve body and a first rotor rotating outside the first stator, the first rotor has a slot, and the one common port and the eight selection ports are located on the first valve body, and the slot selectively faces one selection port to communicate the selection port with the common port. The eight selection ports are port A, port B, port C, port D, port E, port F, port G and port H respectively.

[0021] The high-pressure injection pump 1, the buffer ring 2 and the common port of the selection valve 3 are sequentially communicated, and the buffer ring 2 is a section of inert pipeline with an internal volume consistent with the range of the high-pressure injection pump 1.

[0022] The sample injection valve 10 is a two-position six-way valve, having six ports, namely port 1, port 2, port 3, port 4, port 5 and port 6. The sample injection valve 10 has two phases, in one phase, 1-2, 3-4 and 5-6 three groups of ports are connected to each other, in the other phase, 1-6, 2-3 and 4-5 three groups of ports are connected to each other. The sample injection valve 10 is provided with a quantitative ring. The sample injection valve 10 includes a second valve body, a second stator located in the second valve body and a second rotor rotating on the outer periphery of the second stator.

[0023] The material of the selection valve 3 and the sample injection valve 10 is stainless steel or polyether ether ketone, which is an inert material not reacting with the analyte and the reagent used.

[0024] The sample base 5 is used for placing the sample tube 4, and the vibration motor 6 is arranged on the sample base 5 to realize the function of shaking and extracting the oil sample. The sample base 5 is provided with an opening hole above which the sample tube 4 can be inserted, and the insertion interface uses a luer interface. The opening hole is a through hole below, and is connected to the selection valve 3 through a pipeline. The sample base 5 and the sample tube 4 are inert materials not reacting with the analyte and the reagent used. In this example, the material of the sample base 5 is selected to be stainless steel, and the sample tube 4 is made of polypropylene.

[0025] The online filter 14 is communicated with the sample injection valve 10, and is used for filtering a small amount of particulate matter that may exist in the sample to prevent the device from being blocked. The online filter 14 generally uses a sieve plate or filter core with micropores as a filter material. The filter core is an inert material not reacting with the analyte and the reagent used. In this example, the material is selected to be a stainless steel sintered sieve plate.

[0026] The chromatographic column 11 is communicated with the sample injection valve 10, and the chromatographic column 11 is a core component for realizing separation. The stainless steel shell of the chromatographic column 11 is filled with powdered filler to provide separation capacity. The chromatographic column 11 selects a C18 filler chromatographic column, and is arranged in the column oven 12. The column oven 12 is provided with a heating sheet for heating and a thermocouple for detecting temperature, so as to keep the chromatographic column 11 at a required stable separation temperature. The PTC ceramic heating sheet is used to realize the heating of the column oven 12, and the thermocouple adopts a PT100 thermocouple to feedback the temperature.

[0027] The LED detector 13 is communicated with the outlet of the chromatographic column 11. The outlet of the LED detector 13 is connected to an open pipeline, which is used as a waste liquid outlet. The LED detector 13 uses an LED as a light source, and is a single-wavelength ultraviolet detector for detecting the absorbance at a fixed wavelength of 277 nm. After the chromatographic effluent is introduced into a quartz flow cell, the light absorption condition of the effluent to the LED light source is measured by using a photocell to measure the effluent amount of furfural.

[0028] The battery 15 is used for supplying power to the entire measuring device.

[0029] The eluent container 8, the extract container 9, the standard oil sample container 7, the sample tube 4, the air inlet, the waste liquid outlet, the online filter 14 and the sample valve 10 are respectively communicated with eight selection ports of the selection valve 3. All connecting pipelines of the device are inert pipelines suitable for liquid chromatography systems, and in the present example, the materials are selected to be stainless steel or polyether ether ketone.

[0030] The specific connection of the eight selection ports of the selection valve 3 is as follows: port A is connected to the extraction solvent in the extract container 9, and the extraction solvent is methanol. Port B is connected to the chromatographic eluent in the eluent container 8, and the eluent is a mixed solvent of 50% methanol and 50% water. Port C is connected to the standard oil sample in the standard oil sample container 7. Port D is connected to the bottom of the sample base 5, and the sample base 5 and the vibration motor 6 are connected using soft rubber material to provide the shaking function. The top of the sample base 5 is provided with a jack for inserting the sample tube 4. The jack at the top and the connecting port at the bottom are both through holes, so as to communicate port D and the sample tube 4 through the sample base 5. Port E is connected to an open pipeline as an air inlet. Port F is connected to an open pipeline as a waste liquid outlet. Port G is connected to the inlet end of the online filter 14 as a sample outlet, and the outlet end of the online filter 14 is connected to port 3 of the sample valve 10. Port H is connected to port 1 of the sample valve 10 as a mobile phase outlet.

[0031] The connection of the six ports of the sample valve 10 is as follows: port 1 is connected to port H of the selection valve 3. Port 2 is connected to the quantitative ring inlet. Port 3 is connected to port G of the selection valve 3. Port 4 is connected to an open pipeline as a waste liquid outlet. Port 5 is connected to the quantitative ring outlet. Port 6 is connected to the inlet of the chromatographic column 11.

[0032] The transformer oil rapid determination device has the following four functions: liquid suction and delivery with self-cleaning function, automatic sample extraction function, chromatographic column flushing and elution function, and liquid chromatography sample filtration, sample injection and pipeline self-cleaning function.

[0033] The specific implementation of the above four functions is as follows:

[0034] Function 1: It has self-cleaning function, and the specified volume and speed of liquid suction and delivery. If a volume of V of a certain liquid is required to be sucked from a port M and pushed out to another port N, the pipeline is cleaned after pushing out. The ports M and N are randomly set according to application requirements. The specific process is as follows:

[0035] The selection valve 3 is switched to port F, and the high-pressure injection pump 1 pushes out all the remaining liquid, and the piston reaches the farthest end.

[0036] The selection valve 3 switches to port A, and the high-pressure injection pump 1 sucks 1 mL of methanol, the extraction solvent. Then the selection valve 3 switches to port E, and 0.1-0.2 mL of air is sucked in. Then it switches to the designated suction port M, and the volume V is sucked at the designated speed. For 1 mL of methanol and the certain liquid in volume V, there is air in between as a separator, so the two zones will not mix.

[0037] Then the selection valve 3 switches to the port N that needs to be output, and the high-pressure injection pump 1 piston is pushed out of volume V at the designated speed, and the volume V of liquid sucked from port M in the buffer ring 2 is pushed out to port N. After the infusion is completed, the selection valve 3 switches to port F, and the remaining air and 1 mL of methanol are pushed out. The methanol pushed out can flush the remaining liquid from port M in the buffer ring 2 to achieve self-cleaning of the pipeline.

[0038] Function two: the process of automatic sample extraction is realized in the sample tube inserted into the sample base. If it is necessary to use the extraction liquid with a volume of V1 to extract the sample with a volume of V2. The implementation scheme is as follows:

[0039] Insert the empty sample tube 4 into the sample base 5, and the volume of the sample tube 4 is preferably 2-3 times (V1+V2). Inject V2 volume of the sample to be tested in the sample tube 4. The selection valve 3 switches to port A, and the high-pressure injection pump 1 sucks V1 of the extraction solvent methanol. Then it switches to port D, and the high-pressure injection pump 1 slowly pushes out the extraction solvent methanol. According to the standard DL / T 1355-2014, 8 mL of transformer oil is extracted using 2 mL of methanol, and the infusion amount of methanol is 1 mL / min.

[0040] At the beginning of the methanol infusion, the vibration motor 6 is turned on to realize the shaking function. According to the standard DL / T 1355-2014, the shaking time is 5 minutes. After standing and stratifying, if the target sample is in the lower layer, it is directly sucked from port D to obtain the sample to be tested after extraction. If the target sample is in the upper layer, the selection valve 3 switches to port D to suck out slightly more than V2 of the lower layer liquid; then it switches to port F to completely discharge the lower layer liquid. At this time, only the upper layer liquid remains in the sample tube 4, and it is directly sucked from port D to obtain the sample to be tested after extraction. If necessary, a pipeline cleaning process can be added in between.

[0041] After the extraction is stratified, 1 mL of methanol is sucked from port A, 0.2 mL of air is sucked from port E, and 8.5 mL of lower layer liquid is sucked from port D, and then the waste is discharged from port F, during which the lower layer liquid is discharged and the pipeline is flushed with methanol. Then in the sample injection step, the upper layer methanol layer sample obtained by extraction can be sucked from port D.

[0042] Function three: Chromatographic column flushing and elution function. This measuring device supports the use of two different solvents to flush and elute the chromatographic column 11. Flushing is used to remove impurities and keep the chromatographic column 11 clean, and elution is used to provide the chromatographic column 11 with a mobile phase suitable for analyzing and measuring the sample. Both flushing and elution need to be performed at a specified infusion flow rate and infusion volume. The chromatographic column 11 is flushed using the extractant from port A, which is sucked and pushed out to port H at a specified speed so that the cleaning solvent enters the column head. The elution uses the eluent from port B, which is sucked and pushed out to port H at a specified speed so that the cleaning solvent enters the column head. During the elution process, the column oven 12 is used to keep the chromatographic column 11 at the separation temperature specified by the method.

[0043] During flushing and elution, the injection valve is in a phase where ports 1-2, 3-4, and 5-6 are connected in pairs. Liquid injected into port 1 flows through ports 1 → 2 → sample loop → 5 → 6 → column and enters column 11. Ports 3 and 4 are not in the flow path.

[0044] According to the standard DL / T 1355-2014, column 11 was cleaned using 2.5 mL of methanol drawn from port A at a flow rate of 1 mL / min. Column 11 was eluted using 5 mL of methanol drawn from port B at a flow rate of 1 mL / min. The column temperature was set to 40°C.

[0045] Function 4: Liquid chromatography sample filtration, injection and pipeline self-cleaning. After the above sample extraction step is completed, the sample to be tested retained in the sample tube 4 is filtered and injected into the chromatographic column 11. The specific method of achieving sample flow through the pipeline self-cleaning is as follows:

[0046] Selector valve 3 switches to port A, and high-pressure syringe pump 1 draws 5 mL of extract. Selector valve 3 then switches to port E, drawing 0.1-0.2 mL of air. Then, it switches to port D, drawing a volume of sample, Vs. The drawn air acts as a separator, preventing mixing of the two zones. The volume of the sample loop is Vloop, and the sample draw volume, Vs, is greater than Vloop.

[0047] Next, selector valve 3 is switched to port G, while injection valve 10 is positioned so that ports 1-6, 2-3, and 4-5 are connected in pairs. High-pressure syringe pump 1 is pushed slightly beyond Vloop, but not exceeding Vs. The previously drawn sample zone is filtered through in-line filter 14 before being injected into port 3. The flow proceeds from 3 to 2 to the sample loop, then to 5 and finally to 4, where it is injected into the sample loop. The existing liquid in the sample loop and the excess sample are discharged through port 4.

[0048] After that, the injection valve 10 is switched to the phase of connecting the three groups of ports 1-2, 3-4, 5-6 two by two. The liquid injected into port 1 will enter the chromatographic column 11 through the flow path 1→2→quantitative loop→5→6→chromatographic column. Ports 3, 4 are not in the flow path. All the liquid remaining in the high-pressure injection pump 1 is pushed out from port G, and the 5 mL of extracted liquid previously sucked is used to clean the online filter 14 and the injection line and is discharged through port 4. At this time, the quantitative loop is already filled with the sample after extraction, and after the high-pressure injection pump 1 extracts the eluent, the chromatographic elution is performed according to the set flow rate and elution volume.

[0049] After the elution is completed, an appropriate amount of extracted liquid is sucked. Then, the valve 3 is switched to port D, and the extracted liquid is pushed out, and then the extracted liquid pushed out is sucked again to clean the line from the selection valve 3 to the sample base 5. Then, it is switched to port F, and the extracted liquid cleaned through the line is discharged. If necessary, multiple times can be performed.

[0050] The volume of the quantitative loop is 20 μL, and during injection, 5 mL of methanol, 0.2 mL of air, and then 1 mL of sample are sucked. After 0.5 mL of sample is pushed out and the quantitative loop is filled, the injection valve 10 is switched and the remaining liquid is pushed out to clean the injection line.

[0051] The above is the four functions that can be achieved by the present determination device.

[0052] The following is the specific process of fully automatic extraction and separation determination equivalent to manual operation in DL / T 1355-2014:

[0053] The method is set as follows: the device is equipped with a 10 mL high-pressure injection pump 1, a 10 mL buffer loop 2, a 20 μL quantitative loop, a 277 nm LED detector 13, and the column temperature is set to 40°C.

[0054] The test steps include the following steps A1-A6:

[0055] A1, a disposable sample tube 4 with a luer joint at the lower end is inserted into the sample base 5. 8 mL of oil sample to be tested is injected through port C using a disposable dropper or other appropriate method.

[0056] A2, according to the method of function two described above, 2 mL of methanol is automatically sucked and slowly injected into the sample tube 4 from the interface at the lower end of the sample base 5. At the same time, the sample tube 5 is shaken for 5 min. Wait for the sample to separate, and the system automatically times during this period.

[0057] A3, according to the method of function four described above, the sample is injected into the quantitative loop with a volume of 20 μL, which is the volume of the quantitative loop. The excess sample is discharged from the waste port. Then, the cleaning of the injection line is performed.

[0058] A4. Following the method described in function 3 above, flush the chromatographic column with the eluent at a flow rate of 1 mL / min for 5 minutes and record the UV signal. Data system 16 automatically integrates the chromatographic peak area generated by the sample to obtain the sample peak area As.

[0059] A5. According to the method of function three above, flush the chromatographic column 11 with 2.5 mL of methanol and 3 mL of eluent in sequence at a flow rate of 1 mL / min to clean and balance the chromatographic column 11.

[0060] A6. Follow the method in function 4 above and use 5 mL of methanol to clean the pipeline from port D to sample base 5 twice.

[0061] After the above steps A1-6, the system automatically completes the sample pretreatment and measurement.

[0062] As a quantitative basis, the following steps B1-B6 are taken for the determination of standard samples:

[0063] B1. Insert the disposable sample tube 4 with a Luer connector at the bottom into the sample base 5. Inject 8 mL of standard oil sample into the base through port C.

[0064] B2. Following the procedure described in function 2 above, the system automatically draws 2 mL of methanol and slowly injects it into sample tube 4 from the port at the bottom of sample base 5. Simultaneously, the sample tube is shaken for 5 minutes. The system automatically counts the time while the sample is allowed to separate.

[0065] B3. Following the procedure in function 4 above, the system injects the sample into the loop, with a volume equal to the loop's capacity of 20 μL. Excess sample is discharged through the waste port. The sample line is then cleaned.

[0066] B4. Following the procedure in function 3 above, flush the column with eluent at a flow rate of 1 mL / min for 5 minutes while recording the UV signal. The data system automatically integrates the peak area generated by the sample to obtain the peak area Astd of the standard oil sample.

[0067] B5. According to the method of function three above, flush the chromatographic column 11 with 2.5 mL of methanol and 3 mL of eluent in sequence at a flow rate of 1 mL / min to clean and balance the chromatographic column 11.

[0068] B6. Following the method in function 4 above, use 5 mL of methanol to clean the line from port D to the sample base twice.

[0069] The furfural content in the final sample was C = 0.1 As / A std mg / L. The linear range of the method was 0.01-10 mg / L, and the reproducibility was calculated based on 0.1 mg / L sample, with an RSD of <5%.

[0070] In particular, when there are multiple sample sequences, two samples that are adjacent in time can be partially overlapped in the process. For example, for two adjacent samples A and B, the actual execution order is as follows S1-S9:

[0071] S1. Insert a disposable sample tube with a Luer connector at the bottom into the sample base 5. Use a disposable dropper or other appropriate method to inject 8 mL of the oil sample A to be tested into the base.

[0072] S2. The system automatically draws 2 mL of methanol according to the method described in function 2 above and slowly injects it into sample tube 4 from the port at the bottom of sample base 5. Simultaneously, the sample tube is shaken for 5 minutes. The system automatically counts the time while the sample is allowed to separate.

[0073] S3. Following the method described in function 4 above, the system injects the sample into the loop, with a volume equal to the loop's capacity of 20 μL. Excess sample is discharged through the waste port. The injection line is then cleaned.

[0074] S4. Following the procedure described in function 3 above, flush the column with the eluent at a flow rate of 1 mL / min for 5 minutes while recording the UV signal. The data system automatically integrates the chromatographic peak area generated by the sample to obtain the peak area As of the sample.

[0075] S5. According to the method of function 4 above, use 5 mL of methanol to clean the pipeline from port D to sample base 5 twice.

[0076] S6. As in S1, insert the disposable sample tube with a Luer connector at the bottom into the sample base 5. Use a disposable dropper or other appropriate means to inject 8 mL of the oil sample B to be tested into the base.

[0077] S7. The system automatically draws 2 mL of methanol according to the method described in function 2 above and slowly injects it into sample tube 4 from the port at the bottom of sample base 5. Simultaneously, the sample tube is shaken for 5 minutes. The system automatically counts the time while the sample is allowed to separate.

[0078] S8. While waiting for the sample to be separated, according to the method of function three above, use 2.5 mL of methanol and 3 mL of eluent in sequence to flush the chromatographic column 11 at a flow rate of 1 mL / min to clean and balance the chromatographic column 11.

[0079] S9: Similar to S2-S5, aspirate the extracted sample B for analysis and determination, and clean the line from cleaning port D to the sample base twice. Similar to S5 and S6, the chromatographic column 11 can then be flushed and re-equilibrated while the next sample is extracted and awaiting separation.

[0080] This process takes approximately 13 minutes per sample.

[0081] The embodiment adopts similar structure of liquid chromatography, but simplifies the device and successfully combines the functions of automatic pre-extraction, automatic filtration, automatic sampling, automatic chromatographic elution and quantitative multi-step functions. The above equipment is integrated on a small-sized machine body with a total weight of about 10 kg, and the device can easily realize mobile work and on-site analysis. The whole process of the device is fully automatic, after the transformer oil sample to be detected is added in the sample tube 4, all analysis and self-cleaning steps are automatically executed. The measured result is compared with the determination result of the built-in standard oil sample, and the measurement result is automatically obtained. No human intervention is required in the process, and the operator does not need experimental experience and special training to use it conveniently.

[0082] The embodiment of the utility model is described in detail above in combination with the drawings, but the utility model is not limited to this, various changes can be made within the knowledge range of the technical personnel in the technical field without departing from the purpose of the utility model.

Claims

1. A rapid determination device for furfural in transformer oil, characterized in that: With waste and air inlets, including: A selection valve (3) having a common port and eight selection ports which are selectively connected to the common port by adjustment; An injection assembly comprises a high-pressure injection pump (1) and a buffer ring (2), wherein the common ports of the high-pressure injection pump (1), the buffer ring (2) and the selection valve (3) are connected in sequence; a standard oil sample container (7), an eluent container (8), an extraction liquid container (9), and a sample tube (4); The injection valve (10) is a two-position six-way valve with six ports, two phases, and a built-in quantitative loop; an in-line filter (14), which is in communication with the injection valve (10); a column oven (12) having a built-in chromatographic column (11) connected to the injection valve (10), and having a heating plate for heating and a thermocouple for detecting temperature; an LED detector (13), which is in communication with the chromatographic column (11); a battery (15) for power supply; The eluent container (8), the extracting liquid container (9), the standard oil sample container (7), the sample tube (4), the air inlet, the waste liquid port, the online filter (14) and the injection valve (10) are respectively connected to the eight selection ports of the selection valve (3).

2. A rapid determination device for furfural in transformer oil according to claim 1, characterized in that, The buffer ring (2) is a section of inert pipeline with an internal volume consistent with the measuring range of the high-pressure injection pump (1).

3. A rapid determination device for furfural in transformer oil according to claim 1, characterized in that: The selection valve (3) comprises a first valve body, a first stator located inside the first valve body, and a first rotor rotating on the periphery of the first stator. The first rotor has a slot. A common port and eight selection ports are all located on the first valve body. When one of the slots faces a selection port, the selection port is connected to the common port.

4. A rapid determination device for furfural in transformer oil according to claim 3, characterized in that, The injection valve (10) comprises a second valve body, a second stator located in the second valve body, and a second rotor rotating around the outer periphery of the second stator.

5. A rapid determination device for furfural in transformer oil according to claim 4, characterized in that, The selection valve (3) and the injection valve (10) are both made of stainless steel or polyetheretherketone.

6. A rapid determination device for furfural in transformer oil according to claim 1, characterized in that: The invention also comprises a sample base (5) for placing the sample tube (4) and a vibration motor (6) arranged on the sample base (5).

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