Triple Expansion Method: Micro-Vapor Pressure Tester
Triple Expansion Method Vapor pressure, an important parameter of substance volatility, refers to the pressure exerted by a substance’s vapor at its liquid (or solid) surface at a specific temperature. When gas and liquid (or solid) phases reach dynamic equilibrium, the measured pressure is the substance’s saturated vapor pressure at that temperature. For oils, vapor pressure indicates the tendency of lighter components to vaporize from the liquid state into space; higher values indicate greater volatility and storage challenges.
Various methods for measuring vapor pressure exist globally, tailored to different test subjects and techniques, but share the basic principle of expanding a fixed-volume liquid several times its original size at a specific temperature to measure pressure, as per methods like ASTM D6378. This method, known as the Triple Expansion Method, is widely adopted for its accuracy, good repeatability, and high level of automation worldwide.
Micro-Vapor Pressure Tester
Introduction
Zeal Instruments introduces its Micro-Vapor Pressure Tester, a precision instrument boasting top-tier testing accuracy and an extensive pressure range. This device is designed to assess the vapor pressure of a variety of substances including liquefied petroleum gas (LPG), crude oil, gasoline, kerosene, and various chemicals and solvents. Utilizing the advanced triple expansion method, the tester is ideal for applications within the petroleum and chemical industries, enabling accurate determination of vapor pressure for substances such as gasoline, aviation gasoline, hydrocarbon solvents, light petroleum distillates, and chemical reagents.
Key Features and Functionality
The Micro-Vapor Pressure Tester stands out with its ability to operate without sample pre-treatment and complete experimental operations at the push of a button. It is fully automated, significantly reducing potential errors from manual handling. The device requires only 1 ml of the sample to produce results within 10 minutes. It offers flexibility in setting and automatic detection across multiple temperature points, facilitating the quick compilation of temperature-pressure reference charts. Moreover, its unique cleaning method minimizes sample cross-contamination, thus enhancing both detection efficiency and precision.
Technical Specifications and Standards Compliance
This tester operates efficiently within a temperature range of 5°C to 40°C and accommodates a broad vapor pressure range from 0 to 1000 kPa with a precision of 0.01 kPa. Its temperature accuracy is remarkable at ±0.1°C. The micro steam pressure tester complies with many international standards such as SH/T 0769, SN/T 2932, ASTM D6378, SH/T 0794, ASTM D5191, GB/T 8017, ASTM D323, EN 13016-1 and IP 394. It ensures its reliability and repeatability under various operating conditions. The structure design of the equipment is compact and sturdy. The size is 225mm x 290mm x 390mm and the weight is 12kg, which is suitable for intensive testing environment.
User Interface and Data Management
The user interface of the Micro-Vapor Pressure Tester is designed for optimal user-friendliness, featuring a 7-inch color LCD touchscreen that dynamically displays the experimental process. The system is equipped with USB, RS232, and RJ45 ports for easy connectivity and data management. An optional thermal printer can be added for immediate printouts of results. With user hierarchical management, the device allows for controlled access at different administrative levels, enhancing its utility in environments where multiple users or teams may need access to the testing equipment. This aspect of design not only secures the data but also facilitates seamless integration into existing workflows in laboratory settings.
Overview of Testing Procedures
Testing vapor pressure involves a methodical approach to ensure precise and consistent results. Proper preparation and adherence to specific conditions are critical for achieving reliable data. Below are the steps necessary to effectively operate the testing equipment.
Step 1: Cylinder Preparation and Cleaning
Begin by thoroughly cleaning the test cylinder with methanol. This initial wash removes any contaminants. Follow up with three rinses using the sample to be tested. This process eliminates residues from previous tests, preventing contamination and ensuring the cylinder is suitable for the new sample.
Step 2: Setting Temperature and Gas-to-Liquid Ratio
Prepare the test cylinder by adjusting the sample temperature within the range of 0°C to 100°C. Set the gas-to-liquid ratio between 4:1 and 0.02:1. These parameters significantly impact vapor pressure dynamics in the cylinder, directly influencing measurement accuracy.
Step 3: Sample Injection and Equilibrium
Connect the syringe containing the sample to the instrument’s injection port. Inject precisely 10 mL of the sample into the test cylinder using the piston. Adjust the sample volume to achieve the desired gas-to-liquid ratio post-expansion. The instrument performs triple expansion autonomously to reach vapor pressure equilibrium. Once stabilized, record the test results detailing vapor pressure under the set conditions.
Step 4: Equipment Maintenance
After testing, clean the instrument thoroughly with methanol to remove any sample residues. This ensures the equipment is primed for future tests, free from potential contamination. Regular cleaning and maintenance are essential to uphold accuracy and extend the instrument’s lifespan.
In Closing
The Triple Expansion Method used in the Micro-Vapor Pressure Tester represents a significant leap forward in accurately and efficiently measuring vapor pressures. This approach ensures precise and reproducible testing of volatile substances such as gasoline, LPG, and various chemicals, proving invaluable in the petroleum and chemical sectors. By automating the expansion process and reducing human error, this tester streamlines laboratory workflows, enhancing the reliability of results. Its ability to operate with minimal sample quantities and deliver rapid outcomes underscores its suitability for high-volume testing environments. In short, the Micro Vapor Pressure Tester sets a new benchmark in vapor pressure analysis. It combines advanced technology with user-friendly design. It effectively meets the stringent requirements of industry applications.
