Attach gauges or sensors to these valves so you can remove them for maintenance and calibration without depressurizing your line. Also known as block and bleed valves, turn the handles to block both upstream and downstream flow, drain the liquid trapped in the valve through the bleed port, and then remove your instrument from the gauge port. Often used in chemical-processing lines, these valves have a PTFE seal and a corrosion-resistant 316 stainless steel body. All are standard port, so they slightly restrict flow.

Flow coefficient (Cv) is the amount of water (in gallons per minute) at 60° F that will flow through a fully open valve with a difference of 1 psi between the inlet and the outlet.