English to German Tech/Engineering Mechanics / Mech Engineering Valves

Context:

"Through conduit gate valves; which should be used either in the fully open or fully closed position."

Hier ein Bild zu dieser Art der Ventile:
http://www.newayvalve.com/en/product/product-content.jsp?pro...

Hier von einem anderen Hrsteller:
http://www.fluitekvalves.com/product/gate-valves/through-con...
"
Through conduit gate valves are an alternative to ball valves for transmission pipelines. The choice is very often based on past customer satisfaction, more than any technical consideration. FLUITEK ORSENIGO VALVES through conduit valves feature standard principles of this well known type of product. The disc is of slab type gate, seat rings are floating, energized by means of multiple springs, and the line fluid pressure pushes the upstream ring against the disc, thus assuring the sealing. The system allows the so called “self relieving” effect, i.e. any over-pressure acting in the body cavity is discharged in the line when force caused by the over-pressure on the seats exceeds the force provided by the springs. At the same time, the construction permits the double block and bleed functioning meaning that pressure applied contemporaneously upstream and downstream pushes both seats against the disc and opening the body cavity bleed relieves any pressure and fluid in the body cavity."