What method can be used to detect non-condensables in a refrigerant recovery cylinder?

What method can be used to detect non-condensables in a refrigerant recovery cylinder?

• A. Weight Measurement
• B. Sound Test
• C. Comparing cylinder pressure and temperature to a PT chart
• D. Visual Inspection

Answer: (C)

Using a PT (pressure-temperature) chart to compare the cylinder pressure and temperature is an effective method to detect non-condensables in a refrigerant recovery cylinder. This approach leverages the properties of refrigerants, which have predictable pressure and temperature relationships at specific conditions. When non-condensables, such as air or moisture, are present in the cylinder, they will affect the pressure readings of the refrigerant, leading to discrepancies when compared to the expected values indicated by the PT chart. If the pressure does not correspond to the temperature at which the refrigerant should condense, it suggests the presence of non-condensable gases. This method is preferred because it's based on established thermodynamic principles and provides a clear indication of the mixture's composition. Other methods, while they may have their uses, lack the precision or reliable correlation to directly identify the presence of non-condensables in the same way. For instance, weight measurement doesn't specifically indicate the gas composition, a sound test may not yield accurate information about the gaseous content, and visual inspection is not effective for identifying non-condensables that are typically not visible.

Using a PT (pressure-temperature) chart to compare the cylinder pressure and temperature is an effective method to detect non-condensables in a refrigerant recovery cylinder. This approach leverages the properties of refrigerants, which have predictable pressure and temperature relationships at specific conditions.

When non-condensables, such as air or moisture, are present in the cylinder, they will affect the pressure readings of the refrigerant, leading to discrepancies when compared to the expected values indicated by the PT chart. If the pressure does not correspond to the temperature at which the refrigerant should condense, it suggests the presence of non-condensable gases.

This method is preferred because it's based on established thermodynamic principles and provides a clear indication of the mixture's composition. Other methods, while they may have their uses, lack the precision or reliable correlation to directly identify the presence of non-condensables in the same way. For instance, weight measurement doesn't specifically indicate the gas composition, a sound test may not yield accurate information about the gaseous content, and visual inspection is not effective for identifying non-condensables that are typically not visible.