Degassing Oscillation Test for Transformer Insulating Oil Overview Transformer insulating oil is the core liquid medium inside oil-filled power transformers. Refined from petroleum fractions, it features excellent insulation and thermal conductivity, and undertakes three core functions during equipment operation: insulation protection, heat dissipation and cooling, and arc extinguishing and buffering. It is a critical material to ensure the stable operation of transformers. During long-term operation of transformers, insulating oil will gradually age under the action of high temperature, electric field and oxidation. On the one hand, it will decompose and produce dissolved gases such as hydrocarbons, carbon monoxide and carbon dioxide, and abnormal components of these gases often indicate latent faults such as overheating and discharge inside the equipment. On the other hand, it will generate water-soluble acidic substances. Excessive acidic substances will corrode metal components and insulating materials, accelerate equipment aging, and even cause insulation breakdown accidents in severe cases. Therefore, dissolved gases and water-soluble acids are the core indicators of insulating oil testing, and constant-temperature oscillation degassing is an essential pretreatment step for both tests. Experimental Purpose The degassing of dissolved gases in insulating oil and the dissolution of water-soluble acids are completed through constant-temperature oscillation treatment, to provide qualified samples for subsequent testing, so as to determine the aging degree of insulating oil and the operation status of transformers. The experiment strictly complies with GB/T 17623-1998 Determination of Components of Dissolved Gases in Insulating Oil by Gas Chromatography and DL 429.4-91 Quantitative Determination of Water-Soluble Acids. The SH121 Degassing Oscillator used in this test is developed and manufactured in accordance with the method requirements of the two standards. Experimental Samples and Instruments Experimental sample: In-service transformer insulating oil Experimental instruments and consumables: SH121 Degassing Oscillator 100mL glass syringes, sealing rubber caps Calibration glass thermometer Cleaning and wiping consumables Operation Procedures 1. Chromatographic Degassing Oscillation (Corresponding to GB/T 17623-1998) Slowly inject the insulating oil sample to be tested into a 100mL glass syringe, expel all air bubbles and seal it. Place the syringes steadily on the double-layer sample carrier inside the instrument in turn, and close the upper cover. Turn on the power supply, and select the chromatographic degassing oscillation mode on the main interface of the 5-inch color touch screen. The instrument has pre-set parameters in accordance with the standard: constant temperature of 50℃, oscillation for 20 minutes, and constant-temperature standing for 10 minutes. After clicking start, the instrument automatically completes the whole process of temperature rise, oscillation and standing without manual attendance throughout the process. The screen displays the current temperature and operation status in real time. At the end of the experiment, the instrument gives a buzzer prompt. Take out the samples for subsequent gas chromatography component detection. The operation can be stopped or returned to the main interface at any time during the process. 2. Water-Soluble Acid Oscillation (Corresponding to DL 429.4-91) Prepare the oil sample and extractant according to standard requirements, put them into the syringe and seal it, fix it on the sample carrier, and close the upper cover of the instrument. Select the water-soluble acid oscillation mode on the main interface. The instrument pre-sets a constant temperature of 75℃ and oscillation for 5 minutes in accordance with the standard. After clicking start, the instrument runs automatically and gives a buzzer reminder when finished. Take out the samples for quantitative titration of water-soluble acids. 3. Custom Oscillation Mode For personalized oscillation pretreatment requirements of other oil products, the custom oscillation mode can be selected. The target temperature can be freely set within the range from room temperature to 100℃, and the oscillation duration and constant-temperature standing duration can be adjusted within 0-99 minutes, to adapt to different experimental requirements. Data Analysis and Result Evaluation Parallel test verification was carried out on multiple groups of standard insulating oil samples, and the test results of samples treated by the SH121 Degassing Oscillator are stable and reliable: Temperature control accuracy meets standard requirements: the temperature control accuracy reaches ±0.2℃ in the range of room temperature to 50℃, and ±0.3℃ in the range of 50℃ to 100℃. The constant temperature state is stable without obvious temperature fluctuation, and the degassing and dissolution effects will not be affected by temperature deviation. Excellent consistency of treatment effect: with 35mm oscillation amplitude and stable oscillation frequency of 275±3 times per minute, it can fully separate dissolved gases in oil, and also ensure the complete dissolution of water-soluble acidic substances. The detection deviation of parallel samples is within the allowable range of the standard, with good repeatability. Adaptable to laboratory batch testing needs: it can hold 8 pieces of 100mL syringes at the same time in a single run, supporting synchronous pretreatment of batch samples, which greatly improves detection efficiency. The low-noise transmission design and compact body can also well adapt to the layout of conventional laboratory benches.

 Determination of Moisture Content in Samples 1. Product Overview   Trace moisture is a key indicator for evaluating the quality of various chemical raw materials, oil products, pharmaceuticals and mineral materials. Excessive moisture will directly impair product performance, shorten shelf life and bring potential operational risks.   The Karl Fischer Coulometric Titration method is currently the mainstream technique for trace moisture determination across industries, featuring high testing accuracy and broad applicability.   The SH103 Fully Automatic Trace Moisture Analyzer is developed and manufactured by Shandong Shengtai Instrument Co., Ltd. Based on the classic Karl Fischer Coulometric Titration principle, it can accurately measure trace moisture in liquid, gas and solid samples. This instrument is widely used in petrochemical industry, oil-filled electrical equipment, pharmaceuticals, pesticides, mineral raw materials and other fields.   Equipped with a 7-inch color LCD touch screen for intuitive operation, it boasts high sensitivity, fast testing speed and excellent data repeatability. It also supports data storage, historical record query and result printing. With high automation and user-friendly design, it is a common device for routine trace moisture testing.   2. Test Objectives   Accurately determine the trace moisture content of test samples so as to control product quality and operational safety. This test is conducted strictly in accordance with the Karl Fischer Coulometric Titration principle using the SH103 Trace Moisture Analyzer. The high precision of the instrument ensures authentic, accurate and reliable test data.   3. Test Preparation 3.1 Test Samples： Test samples (liquid, gas or solid, selected according to actual test objects) 3.2 Instruments and Accessories 1. Main unit of SH103 Trace Moisture Analyzer 2. Matching electrolytic cell, electrolytic electrode and measuring electrode 3. Microsyringe, silicone pad, indicator silica gel and magnetic stir bar 4. Special Karl Fischer electrolyte, absolute ethanol, acetone and other auxiliary reagents   4. Operating Procedures 1. Inspect the appearance of the instrument, electrodes, pipelines and drying tubes. Confirm that the silica gel is still effective and all electrodes are firmly connected. Assemble the electrolytic cell as required and pour a sufficient amount of electrolyte into it. 2. Connect to AC220V power supply and turn on the instrument. The device will start up automatically and enter the home interface. Tap the screen to access the function selection page. 3. Set relevant parameters as required: adjust system time and sample serial number, and enable or disable the automatic printing function as needed. Select the corresponding calculation formula (F0, F1, F2) based on sample type, and set stirring speed, sample volume, mass, density and other basic parameters. 4. After parameter configuration, enter the test interface. Turn on stirring and electrolysis functions. The instrument will start stirring and electrolyte balancing. When the screen shows "Balanced", the electrolyte preparation is completed. 5. Draw the test sample with a microsyringe. Insert the needle into the electrolyte and inject the sample slowly, then tap the test button to start detection. Avoid touching the inner wall of the electrolytic cell and electrodes with the sample to prevent deviation of test results. 6. The instrument will perform electrolytic titration automatically. A buzzer will sound upon test completion, and the moisture content value will be displayed on the screen directly. Print the test report if needed. All test data will be automatically saved to the instrument’s historical records. 7. For continuous testing, proceed with the next sample directly after one test is finished. Upon completion of all tests, cut off the power supply, clean the electrolytic cell, electrodes and pipelines, and store all equipment and accessories properly.   5. Data Analysis and Result Evaluation   The sensitivity of the SH103 Trace Moisture Analyzer reaches 0.1 μg H₂O. For moisture content ranging from 10 μg to 1 mg, the test error is only ±3 μg. For moisture content above 1 mg, the error is controlled within 0.3% (excluding sampling error).   Multiple parallel tests on the samples show favorable data repeatability and stable results, which fully meet the accuracy requirements for trace moisture testing in various industries. Featuring stable operation and simple operation, the instrument is applicable to routine batch testing and high-precision laboratory analysis.

Determination of Extreme Pressure and Anti-wear Properties of Lubricating Oil Overview   As essential lubricating media for mechanical equipment, lubricating oil forms protective oil films on friction pairs to reduce metallic wear and prevent oxidative corrosion. Classified into industrial oil, automotive oil and lubricating grease per service conditions, its extreme pressure and anti-wear performance directly impacts equipment service life. Under heavy-load conditions, broken oil film may cause metal sintering and mechanical seizure, hence national standards mandate regular physical and chemical testing of lubricants.   Test Purpose   Determine four core indicators including last non-seizure load (PB), weld load (PD), mean Hertz load (ZMZ) and friction coefficient to evaluate load-bearing and anti-wear capacity for heavy-duty application. Tests comply with GB/T12583-98, GB3142-82, SH/T0189-92 and ASTM D5183-2005, using SH120 automatic four-ball friction and wear tester.   Test Samples & Instruments Sample: Industrial lubricating oil / grease Equipment: SH120 automatic four-ball tester, Φ12.7mm standard steel balls, high/normal-temperature oil cups and cleaning accessories.   Test Procedures 1. Fix three standard steel balls inside the oil cup and clamp one single ball onto the spindle taper hole; submerge contact points with test oil. 2. Power on tester and connected computer, launch control software, select corresponding standard test mode (PB/PD/friction coefficient), set load, spindle speed, test duration and temperature parameters. 3. Preheat equipment for 15 minutes, lift loading piston to reset readings of friction force, test load and timing; adjust temperature to preset value via temperature control module. 4. Start test; the spindle drives the upper ball to rotate for point-contact sliding friction. The system collects real-time friction and temperature data and plots relevant variation curves automatically. 5. Auto-stop upon test completion, unload piston, take out oil cup and measure wear scar diameter under microscope for parameter calculation.   Data Analysis & Conclusion   Step-load testing is conducted in accordance with standard specifications. For qualified oil specimens, intact lubricating film and stable friction coefficient are maintained during graded loading, with PB=1220N and PD=2450N. After 60min test under 392N load and 1450r/min, average wear scar diameter is 0.39mm and ZMZ reaches 35.0N, meeting technical requirements for heavy machinery lubrication. In contrast, inferior lubricants feature poor load resistance, low PB & PD values, oversized wear scars and fluctuating friction, which will significantly accelerate component abrasion in practical operation.  

Determination of Dielectric Strength of Insulating Oil Overview Insulating oil is an important liquid insulating medium, widely used in high-voltage electrical equipment such as transformers, oil circuit breakers, oil-filled cables and power capacitors. It functions for insulation, heat dissipation and arc extinction. During long-term operation, insulating oil is prone to deterioration under the effects of oxygen, high temperature, humidity and impurities, which degrades its insulation performance and directly endangers the safe operation of electrical equipment.   Experimental Purpose Testing the dielectric strength (breakdown voltage) of insulating oil can accurately judge the insulation quality of oil samples and evaluate the operational safety status of equipment. The test is carried out in accordance with GB507-86 Determination of Dielectric Strength of Insulating Oil and IEC-156 standards, using the SH125A insulating oil breakdown voltage tester.   Experimental Samples and Instruments - Test sample: Insulating oil to be tested - Test instruments: 1. SH125A insulating oil breakdown voltage tester 2. Special insulating oil cup, suede cloth, cleaning reagents and other accessories   Operation Procedures 1. Clean the oil cup, adjust the electrode gap to 2.5 mm, place the magnetic stirrer inside, and fill with an adequate amount of test insulating oil. 2. Place the oil cup steadily into the high-pressure chamber of the instrument, cover the high-pressure hood and close the safety switch; connect the power supply and ensure reliable grounding. 3. Preset test times, stirring and standing time via the instrument panel, then enter standby mode after setting. 4. Press the Test key; the instrument automatically completes stirring, standing, pressure rising, breakdown detection and data recording. 5. After the test, the instrument automatically calculates and displays the average value and supports one-click printing of test reports.   Data Analysis and Result Evaluation Nine dielectric strength tests were performed on insulating oil with the SH125A tester under the standard electrode gap of 2.5 mm. The minimum breakdown voltage was 35.4 KV, the maximum 43.5 KV, and the average 39.8 KV. All measured values exceed the national qualified standard of ≥35 KV. The test data show small fluctuation and good repeatability, proving the instrument features high measurement accuracy and stable performance. The tested insulating oil meets the requirements of GB507-86 and IEC-156 specifications with qualified insulation performance, and can be safely applied to various high-voltage electrical equipment.

Test Method for Carbon Tetrachloride Adsorption Rate of Coal-based Granular Activated Carbon Coal-based granular activated carbon is a black columnar or irregular porous carbon adsorbent made from high-quality anthracite coal and tar via carbonization and activation. It is one of the most common types of coal-based activated carbon. It features high mechanical strength, easy regeneration, large specific surface area, strong adsorption capacity and low cost. Its physical strength is no less than 90.0%, with specific surface area generally ranging from 900 to 1000 m²/g. Pores are mainly micropores below 1 nanometer with a small number of mesopores. It boasts favorable chemical stability, acid, alkali, high temperature and high pressure resistance, and can be reused after regeneration. Test Objectives Adsorption performance evaluationCarbon tetrachloride has similar molecular size to most organic contaminants. Its adsorption rate directly reflects micropore development degree and saturated adsorption capacity for non-polar organic pollutants such as VOCs. Higher rate means stronger adsorption capability.     Production quality controlAs a core factory inspection index for gas-phase adsorption activated carbon, this test verifies activation effect, ensures batch product compliance and realizes in-process quality management. Application selection guidanceAdsorption requirements vary in different scenarios. The index provides reference for product selection in air purification, organic waste gas recovery, gas mask and other gas-phase treatment applications. Environmental safety assessmentIt predicts adsorption efficiency in organic pollutant treatment projects, guarantees environmental safety and supplies technical parameters for project design. Test Samples and Equipment Sample: Coal-based granular activated carbon Equipment: ST-65 Carbon Tetrachloride Adsorption Rate Tester, compliant with GB/T7702.13 Test Procedures Sample preparationDry the test sample in an oven at 150℃ for 2 hours, then cool down to room temperature in a desiccator. Adsorption tube pretreatmentWeigh the clean empty tube and record the mass m1. Fill the cooled carbon sample layer by layer with bed height controlled at (100±0.2) cm. Seal the tube tightly and apply vaseline to ensure air tightness. Adsorption processFix the tube in a constant temperature water bath at 25℃. Feed stable saturated carbon tetrachloride vapor until the carbon reaches adsorption saturation with constant weight. Final weighingTake out the tube, wipe off external condensed liquid and weigh immediately to record mass m2. Conduct blank test following identical steps and record blank mass variation m0. Test Result Two parallel test results are 150.5% and 150.2%. The absolute difference is 0.3%, less than the allowable 0.5%, meeting repeatability standard. The final test result is 150.4%.  

Determination Method of Moisture Content in Pesticides Pesticides refer to mixtures and preparations composed of one or several chemically synthesized substances, biological sources or other natural substances, which are used to prevent and control diseases, insects, weeds, rodents and other harmful organisms endangering agriculture and forestry, as well as to purposefully regulate the growth of plants and insects. As defined in the Regulations on Pesticide Administration, pesticides include not only traditional insecticides, fungicides and herbicides, but also non-lethal products such as plant growth regulators. The modern pesticide concept has shifted from the early focus on eliminating pests to emphasizing regulation and ecological environmental harmony. Experimental Purpose This experiment aims to learn the determination method of moisture content in pesticides, master its influence on product quality, stability and efficacy, and ensure pesticides comply with national standards through scientific testing. Guarantee product quality: Excessively high moisture content will cause caking, decomposition or stratification of pesticides, and affect the stability and efficacy of active ingredients. Optimize production processes: Guide enterprises to adjust drying, formula and packaging processes via test data to improve product uniformity. Avoid storage deterioration: High moisture easily leads to mildew, hydrolysis and package corrosion, shortening shelf life. Testing effectively avoids such storage risks. Distinguish formulation standards: Different formulations such as emulsifiable concentrates and wettable powders have different moisture limit requirements. This test accurately judges product qualification. Test Samples and Instruments Test Sample: Pesticide Test Instrument: STNY-102 Automatic Pesticide Moisture Tester, compliant with GB/T 1600 Test Procedures 1. Reagent Calibration Add an appropriate amount of anhydrous methanol into the titration cell, start the tester and titrate to the end point with Karl Fischer reagent to remove trace moisture in methanol. Accurately inject 10μL pure water (about 0.0100g) into the titration cell with a dry syringe, record the consumed volume (V_1) of Karl Fischer reagent. Repeat calibration for 3 times and calculate the average titer T (mg/mL), formula: (T = m_1/V_1) ((m_1) stands for pure water mass). 2.Sample Determination Solid sample: Accurately weigh 0.5-5g sample (adjust weight according to moisture content to ensure reagent consumption within 1-10mL), quickly add into the titration cell, stir to dissolve and titrate to the end point, record the consumed reagent volume (V_2). Liquid sample: Draw proper amount of sample with dry syringe, inject into the titration cell and perform titration following the same steps above, record (V_2). Blank test: Use the same volume of anhydrous methanol to replace the sample for blank titration, record the consumed reagent volume (V_0). Test Result The average moisture content of emulsifiable concentrate samples is 0.81%, which meets the requirements specified in GB/T 1600.