What is an advantage of a "non-pusher" seal over a "pusher" seal?

The statement that a "non-pusher" seal has reduced wear due to less movement of the sealing ring highlights a significant advantage of this design compared to a "pusher" seal.

In a "non-pusher" seal, the sealing elements are typically static or have minimal movement. This characteristic helps to maintain the integrity of the sealing surfaces over time, reducing the rate of wear caused by friction. Unlike "pusher" seals, which often require more movement as the components expand, contract, or rotate, "non-pusher" seals minimize this dynamic interaction, leading to a longer lifespan and improved reliability in service.

The other options, while potentially relevant factors in seal design, do not directly describe the primary mechanical advantage associated with reduced wear. For instance, the complexity of installation may vary depending on the specific application and design constraints, and cost of materials can be influenced by many other factors beyond the basic seal type. Similarly, sealing efficiency can depend on various elements, including the operating conditions and the specific application, rather than solely the design type (pusher vs. non-pusher).