To sum outcome of consideration of the above-described structures, it can be concluded that all the described valves prospects are not widely used. One has to wonder why such companies as Cameron, JSC 'Tyazhpromarmatura' and OOO 'Plant 'Gazprommash' spending money on maintenance of patents. The main drawback – it is the need to press the plug into the seat, which is loaded with the whole area of cross-section of the pressure work environment. Our ancestors in ancient antiquity knew that gravity is better to move, rolling (rotate cranes loaded jam in the traditional design) or podklinivaya and moving (as block valves), and without looking up (as suggested here). All the above valves require a significant moment in the management of the spindle and, therefore, powerful drives (2206809, 2188978, 2158866). The same place where used trapezoidal thread (Orbit Valve, 2278311, 2088828, 2273782), clear height increased so much that cranes have become more valves, and given their cost and the inability to apply conventional control a quarter of current drive is to understand what can cause the consumer to buy them is difficult. Simply buy an old acquaintance – the usual wedge valve. If we look at the figures on the ratio of the diameter of the bent lower end of the spindle (which takes all the load of pressure on the stopper valve in the closed position) with respect to the diameter of the passage, then becomes clear that the design is suitable for small diameters and pressures, otherwise the weight of superstructure would be enormous. Extract the best of what is considered inherent in cranes and draw conclusions: – New construction crane should have not treated the cork, and sealing belts only processed: – New construction crane should be able to adjust seal wear during operation, without removing the valve from the pipeline – for control valve must be applied normal circulating quarter drive low power. To achieve this, a more logical solution is to take an unloaded from the pressure of the saddle, than to move the stopper, such designs exist, and consider them in the next article.