Check valves with male stud end
Ball valves and shut-off valves
Check valves in male stud design pass the fluid in one direction only and close the return path on their own. The valve sits directly between the equipment port and the pipe: one end carries a male stud thread from G 1/8" to G 1-1/2", the other a cutting ring end for tubes from 6 L up to 42 L. The range holds 127 versions rated to 400 bar working pressure.
Three details govern the choice: thread size on the equipment, tube series, flow direction. Some valves flow from thread to tube, others from tube to thread; the direction is fixed inside the body and cannot be reversed on site. Available materials are zinc plated steel plus stainless steel 1.4571, supplemented by versions holding an NC cutting ring in 1.4571. Cracking pressure is either 0,2 or 1 bar.
Determine thread size and tube series separately: the stud thread follows the equipment, the cutting ring end follows the installed line. The two sizes often differ, for example tube 15 L (M22x1,5) on a G 1/2" stud. Light series L and heavy series S cannot be swapped, because cutting ring and cone geometry differ. Check the flow arrow before screwing the body in, since a valve fitted the wrong way round blocks the useful direction. Versions holding an NC cutting ring in 1.4571 suit thin walled tubes.
Hydraulic power units, presses and machine tools, where pumps, filters and accumulator lines have to be protected against backflow. Versions cracking at 1 bar keep return lines under preload, while the 0,2 bar version serves suction and replenishing lines running on a small pressure drop. Bodies in 1.4571 go into chemical plants, outdoor installations and washing systems, where plated steel fails.
