Cranes with ball caps – a relatively new and progressive form of reinforcement, which is not more than fifty years. After the launch of their design constantly improved, contributing to the use of ball valves virtually all industries, displacing the traditional wedge gate valves and valve. Particularly rapid growth in production of ball valves in the world had at the beginning of the 80s, which is associated with the beginning of widespread use in Machining CNC machines and the emergence of sealing material Teflon and polyurethane. The advantages of ball valves often include: 1) high integrity, 2) minimal wear of the ball, 3) ease construction, 4) high speed, 5) easy installation and maintenance, 6) low cost of maintenance during operation, 7) long-term trouble-free operation. 8) low hydraulic resistance, 9) absence of stagnant zones, How do these qualities correspond to reality? Consider the details: 1) High tightness. In today's construction cranes type "plug on support" tightness is achieved by constant pressing of the surface Seat seal to the surface of the ball by springs.
The springs are needed for pre-closing element sealing at low pressures, when the effect of "self-packing saddle" is not working. By turning the ball plug tap, seal seats slide over a spherical surface. That they are not out of order, and remains, above mentioned, high integrity cranes, is time-consuming process of manufacturing areas, consisting to obtain the correct form and high purity spherical surface, cover it durable and corrosion-resistant materials. All of this ultimately increases the cost of ball valves.