Question 310General Subjects - QMED70% to pass
Which of the following statements represents the main difference between a stuffing box gland and a mechanical seal for sealing the shaft of a centrifugal pump?
AI Explanation
The correct answer is A.
The main difference between a stuffing box gland and a mechanical seal is that if the packing in a stuffing box gland fails, the leak can be temporarily stopped by tightening the gland. However, if a mechanical seal fails, the entire seal must be replaced to stop the leakage. Packed stuffing box glands are subject to wear over time and require adjustment, while mechanical seals provide a more reliable seal that does not require adjustment.
The other answer choices are incorrect. Packed stuffing box glands are subject to wear, while mechanical seals are not (B is incorrect). The sealing surface of a mechanical seal is perpendicular to the shaft, not parallel (C is incorrect). Both packed stuffing box glands and mechanical seals do not require cooling by the liquid being pumped (D is incorrect).
Related Questions
#308 Which of the following statements is true regarding mechanical seals? #309 Which of the devices listed is used to maintain a snug interface between the rotating and stationary seal members shown in the illustration? Illustration GS-0071 #311 One disadvantage of using a mechanical shaft seal instead of mechanical packing is that _______________.#312 Mechanical shaft seals used on water service pumps require lubrication of the seal faces to minimize deposits of foreign matter on those surfaces. Which of the following pressures and lubricants are required? #313 Which of the listed types of seals is used effectively for pumps handling toxic or highly flammable liquids that cannot be permitted to escape into the atmosphere?