Studying the range of pipeline shut-off valves presented on the market, you may notice some oddity. Technical characteristics show that with the same connecting diameter, ball valves have different throughput. The thing is that there are full-pass and incomplete-pass shut-off devices, and their characteristics differ significantly. Moreover, this is not a marriage, but two different products for different purposes, with the same connecting size.
The size of the hole in the locking ball at the full-passage shut-off valve exactly corresponds to the inner diameter of the connecting pipe. As a result, the loss of hydraulic pressure in such fittings is practically zero. There are no swirls of the flow, there is almost no wear, and the duration of operation of the ball valve increases significantly.
The main advantages of full-pass devices include the following features:
The principle of operation of full-bore cranes is based on the rotation of a floating ball with a hole inside an unassembled body. The sealing seat is pressed against the ball valve by the action of a poppet spring. Inside, the device is equipped with a spindle that ensures the position of the sealing rings.
The peculiarity of their design is that the passage hole in the locking ball is 1-3 sizes smaller than the diameter of the connecting pipe. As a result, when the flow of the working medium is moving, a large hydraulic resistance is created. The throughput and pressure of the liquid or gas are reduced.
Initially, you might think that this is bad and you don’t need to make such fittings. However, this judgment is deeply erroneous and sounds due to ignorance of the hydraulic principles of pipeline networks.
Impassable ball valves are installed in places of branches from high-pressure main lines. They reduce the pressure of the transported product and allow you to abandon the additional installation of expensive regulators.
In addition, the design of incomplete cranes is less metal-intensive due to the small size of the locking ball and housing. Consequently, they are cheaper than fittings with a fully open passage and are easier to block. The collapsible design of the housing allows for repairs with the replacement of broken parts.
between full and incomplete ball valves. It just doesn’t make sense to talk about what is better. These are two different types of shut-off valves and each has its own purpose.