Level 1 - Mechanical Seals Quiz #3

The main difference between the 280 and the 255 dual cartridge mechanical seal is that the 280 uses direct centering. This means that the seal is centered directly on the shaft, providing more stability and accuracy in its performance. On the other hand, the 255 seal does not use direct centering.

The main difference between an S20 and a 250 mechanical seal is the type of seal used. The S20 uses a cassette seal, while the 250 uses a cartridge seal. The cassette seal is a single unit that contains all the necessary components, such as the seal faces and springs, in a compact design. On the other hand, the cartridge seal is modular and allows for easy replacement of individual components. This difference in design affects the ease of installation and maintenance of the seals.

The minimum pressure requirement when providing barrier fluid is 20-30 Psi (or 2 BAR above stuffing box pressure). This ensures that there is enough pressure to prevent the process fluid from leaking into the barrier fluid and causing damage to the equipment. Higher pressure helps to create a reliable barrier between the process fluid and the barrier fluid, reducing the risk of contamination and maintaining the integrity of the system.

The S20 will not fit this seal chamber because the diameter of D4 is 4.500 inches, which is larger than the maximum diameter of the S20.

The mechanical seal models 255 and 280 are designed to allow motion.

The given statement is true because it states that the least expensive Chesterton dual mechanical seal is the 250. This implies that there are other more expensive options available, but the 250 is the most affordable among them.

The seal models that use monolithic seal faces are 280, 255, and S20.

The key feature of the 280 versus the 255 mechanical is the direct centering clips. These clips help in aligning and centering the mechanical component properly, ensuring its optimal performance. They provide stability and prevent any misalignment or movement during operation. This feature is essential for maintaining the efficiency and longevity of the mechanical system.

The given question is asking for an O-ring size that is not used in a S20 -15 (1.875 inch) dual seal. The correct answer is -137. This means that -137 is not a valid O-ring size for this specific seal.

The correct answer, 2866.00 666018, is the US suggested list price and item number for a 255 -17 SA SSC/CB/SSC/CB 316SS FKM.