Final answer:
The two best shaft seals used in refrigeration compression systems are Carbon ring seals and Mechanical seals, providing durability and effectiveness in maintaining tight seals.
Step-by-step explanation:
In refrigeration compression systems, the effectiveness of a shaft seal is crucial to ensure system efficiency and reliability. Two of the most appropriate types of shaft seals used in these systems are Carbon ring seals (A) and Mechanical seals (D).
Carbon ring seals provide a versatile sealing solution with relatively simple construction and are known for their durability. They are made of segmented rings ensuring tightness and can handle a wide temperature range, which is a common requirement in refrigeration systems.
Mechanical seals are another favorable choice, offering a robust sealing mechanism that is particularly effective in preventing refrigerant leakage. They usually consist of a rotating and stationary face pressed together through spring or hydraulic action to maintain the seal. Due to their sophisticated design, mechanical seals are able to handle high pressures and are suitable for various refrigerant types, making them a popular option in modern refrigeration systems.