Question 1
The Parameters determined by the PV Value are:
A. Power Loss
B. Surface Temperature Increase
C. Wear Rate
D. Lifetime

Question 2:
The contact property of the interface is matter of concern for the Primary and Mating Rings, which are typically chosen from dissimilar materials to reduce friction and wear.
The various forces acting on the floating element of the seal are to be considered to balance the pressure difference across the seal, which affects the mean pressure between the seal faces. A proper balancing with the appropriate balance factor is important, as an underbalanced seal might incorporate too high mean pressure not allowing the minimum clearance. Or an overbalanced seal might introduce leakage of high pressure fluids

Question 3:
Face area A = π (61.8²-49.2²)/4 = 1098 mm²
Balance Ratio B = (61.8²– 52.6²) / (61.8²– 49.2²) = 0.75
Spring Pressure Psp= Fsp / A = 188 / (1098 x 10¯⁶) = 171.22 KPa
The system is unbalanced as the balance ratio is less than 1.

Question 4:
Primary Seals:
A. Retainer
B. Spring
C. Disk
D. Primary Sealing Ring
E. Mating Ring
Secondary Seals:
A. “O” Ring
B. “O” Ring

Question 5:
In the First Figure, we see a cross section of a conventional inside unbalanced seal. Most of the stuffing box pressure is exerting a closing force on the primary sealing ring. Only a small portion of the primary sealing ring face is exposed over the top of the mating ring, allowing a proportionately small amount of pressure to work against the primary sealing ring in the opposite direction (in addition to the opening force exerted by the liquid film between the faces). If the closing force becomes great enough, the liquid film between the faces is literally squeezed out. Deprived of the lubrication, if highly loaded, the faces might soon destroy themselves. The solution to the problem is to balance the seal.
The Second Figure demonstrates a cross section of an outside balanced seal. The shaft packing is forced against the retainer, leaving an area under the seal ring exposed to stuffing box pressure. The closing force exerted by the stuffing box pressure, acting against the shoulder of the seal ring, is slightly greater than the opening force exerted by the liquid film between the faces, thereby keeping the faces in contact at all times.

Question 6:
The Primary Sealing Elements in a single mechanical seal are:
A. Retainer
B. Spring
C. Disk
D. Primary Sealing Ring
E. Mating Ring

A disc-shaped nickel specimen, 50 mm in diameter, is subject to hi...