what device separates Wemmick from the rest of the world?

There are two devices which seperate Wemmick from the rest
of the world. The first is a physical construction. Wemmick's house is a castle,
complete with cannon and drawbridge. He is able to seperate himself and his father off
from the rest of the world by raising their drawbridge and receding into their private
world together. Here we see him as a compassionate and jolly man, entertaining his
father with the cannon and welcoming Pip into his
family.

The second device is less concrete. Wemmick
partitions off his life between work and home life. As clerk to Jaggers the solicitor he
is abrupt, officious and distant. This image is projected to all including Pip, despite
their closeness and trust for each other outside of their business
dealings.