Standard 218 establishes a test procedure to determine the critical solution locus of miscible properties of a lubricant and refrigerant mixture. The standard applies to pure-component refrigerant and lubricants and multicomponent refrigerant and lubricant mixtures.<\/p>\n
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| 1<\/td>\n | ANSI\/ASHRAE Standard 218-2019 <\/td>\n<\/tr>\n | ||||||
| 3<\/td>\n | CONTENTS <\/td>\n<\/tr>\n | ||||||
| 4<\/td>\n | 1. PURPOSE 2. SCOPE 3. DEFINITIONS 4. SAFETY 5. APPARATUS 5.1 Sealed Glass Tubes. One end is sealed to form a rounded bottom with the open-end fire polished. The preparation of these tubes shall be performed by someone skilled in the art of glass blowing. A skilled glass blower shall take into consideration… 5.2 Metal Test Cell. The metal test cell design shall allow charging of refrigerant and lubricant as well as visualization of the liquid and vapor phases. An example design is shown in Figure 1. The cell is constructed of stainless steel and high- pr… 5.3 Charging Manifold. The charging manifold is illustrated in Figure 2. This apparatus consists of a manifold (metal or glass), vacuum pump, pressure gage, high vacuum gage, refrigerant cylinder, valves, and filling ports. The function of this appar… <\/td>\n<\/tr>\n | ||||||
| 5<\/td>\n | Figure 1 Design drawing of a metal test cell. Figure 2 Charging manifold. <\/td>\n<\/tr>\n | ||||||
| 6<\/td>\n | 5.4 Temperature Controlled Bath. A temperature controlled bath (air or liquid) is required to achieve the necessary temperature control and be large enough for testing multiple samples at one time. The bath is constructed to provide a stable temperat… 5.5 Temperature Measuring Devices. The temperature shall be measured with a calibrated temperature device with accuracy \u00b11\u00b0C (\u00b11.8\u00b0F) or better. Suitable devices are type K, type T, type J, thermistor, platinum resistance thermometers, or alcohol… 5.6 Mechanical Vacuum Pump. A mechanical vacuum pump that provides an absolute pressure of 13 Pa (100 mTorr) shall be used. 6. TEST MATERIAL SPECIFICATION AND THEIR PREPARATION FOR USE 6.1 Glass Tube Cleanliness and Inspection. The tubes shall be scrupulously clean and dry. Before use, inspect all tubes for cleanliness and for any cracks, severe scratches, or other faults in the glass. Discard any defective tubes. 6.2 Alternate: Metal Test Cell Cleanliness and Inspection. The metal test cell shall be scrupulously clean and dry. The test cell shall be free of any residues and the windows clean. The cell shall be dried by placing on the charging manifold and pul… 6.3 Refrigerant Purity. The refrigerant used shall meet specifications of AHRI Standard 700 7, or be of known purity. 6.4 Lubricant. The refrigeration lubricant shall be clean and dry per manufacturer\u2019s recommendations. Lubricants can be of two categories: formulated and base stocks. Lubricant shall be identified in the final report. 7. PROCEDURE 7.1 Preparation of Glass Tubes for Testing. Tubes shall be prepared as described in ASHRAE Standard 97 4. 7.2 Preparation of Metal Test Cell for Testing. Metal test cells shall be prepared as described in ASHRAE Guideline 38 8. 7.3 Inspection of Glass Tubes or Metal Test Cells. Wipe each tube or test cell window with a tissue to inspect for the following: 7.4 Measurement of the Miscibility Point <\/td>\n<\/tr>\n | ||||||
| 7<\/td>\n | 8. SIGNIFICANCE OF RESULTS Figure 3 Sample miscibility report. 8.1 Results Reporting. The following information shall be reported: 9. REFERENCES <\/td>\n<\/tr>\n | ||||||
| 8<\/td>\n | INFORMATIVE APPENDIX A: SAFETY <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" ASHRAE Standard 218-2019 – Method of Test for Lubricant and Refrigerant Miscibility Determination (ANSI Approved)<\/b><\/p>\n |