What is the seal function of the outer covering?

Answer 1

There are various applicaitons of mechanical shaft seals, but the most common are centrifugal pumps, propeller shafts on ships, and industrial mixers. The common factor here is a rotating shaft, where one end is in fluid that must be sealed off from the other end. Mechanical seals typically replace packing in a chamber called a stuffing box. Packing is a resilient material. A part called a gland compresses the packing, causing it to expand against the rotating shaft and the walls of the packing chamber, sealing it off. Packing is higher maintenance than a mechanical seal, as it must be continually adjusted as it wears out. If compressed too tightly in the process of eliminating all leakage, packing can cause damage to the shaft. A mechanical seal eliminates the damage and most of the maintenance, but has the drawback of much higher cost.

Answer 2

The seal function of the outer covering is to protect the contents of the item from external elements such as dust, moisture, and contamination. It helps maintain the integrity of the product and ensures that it reaches the end user in good condition.

Answer 3

I think, that its purpose is to protect the tank by the instable pressure inside