double valves

double valves

[¦dəb·əl ′valvz]
(petroleum engineering)
Two valves in series used as subsurface traveling or standing valves in wells, the dual arrangement being more reliable than a single valve.
References in periodicals archive ?
This case is presented for involvement of double valves of heart with regurgitant lesions, which is rare in a young male with Takayasu arteritis.
3 Y-adapter with double valves stopping - 2 400 pieces
Double valves will be installed in the hull to permit the fuel oil to seep by gravity into rigid balloons made of aluminium, capable of holding up to 300m3 of oil.
The Fukuroi plant is one of the first to be equipped with a pneumatic-sender pressure vessel system, whereby a pressure vessel is installed underneath each of the three main scales, which is directly fed by the scale through DFWG double valves and air shut-off valves.