Based on the environment requirements in seaside there exists static and dynamic seal designing for the photoelectric
Theodolite. Static seal designing emphatically includes the designing of o-ring size and mechanical property analysis of
o-ring seal, which is difficult to adopt conventional dynamic seal to meet the requirements. According to practical
application, the combination of the radial labyrinth seal and high quality felt seal are designed. The combination seal
which better solves the seal problem of narrow radial size is a good way of dynamic seal. At the same time, there is
engineering practice needing to proof the radial labyrinth seal.