Stop pneumatic valve and brake valve installation direction difference

in general, for by the pneumatic valve and gate valve installation direction, it is generally easy to confuse. In fact the difference is that by the direction of pneumatic valve is installed, mainly according to the arrow direction of the pneumatic valve body, not according to the higher than that of low into the installation instructions. But some special cases can be high in low out. Pneumatic valve is
gate on both sides of the same.