| 摘要 |
<p>The present invention regards a valve assembly (100) for injecting fluid, preferably a liquid, into a tubing, comprising a first and a second valve sections arranged in series within at least one outer housing (10,11), the first valve section comprises an internal bore (13) in the housing (10) and a first sealing surface (14) and a first valve element (20) arranged movable within the bore (13) with an sealing surface (25) interacting with the first sealing surface (14) of the at least one housing (10,11) to form a metal-metal seal, and pretension means (33) keeping the first valve section in a closed position against a hydrostatic pressure independent of tubing pressure, the second valve section arranged downstream of the first valve section and comprises an internal bore (16) in the housing (11) and a second sealing surface (17) and a second valve element (26) arranged movable within the bore (16) with a sealing surface (31) interacting with the second sealing surface (17) of the at least one housing (10,11) to form a metal-metal seal, and pretension means (34) keeping the second valve section in a closed position until there is a given pressure difference between the fluids on the two sides of the second valve element (26) where the valve assembly in closed state forms a double barrier across the valve assembly. The present invention also regards a tubing element with a valve assembly as defined and a method for operating an injection valve assembly injecting.</p> |
