Technical Document
Mount and operation of integral block and bleed valves
𝗔𝗕𝗔𝗖 𝗩𝗜𝟱 valves provide a safe, simple and unexpensive way for installing gauges, pressure switches, pressure transmitters and indicators. They combines blocking and purge effects in a single unit, this features are essential for the correct installation of this kind of instruments.
Its studied design is used to obtain less leak risks in the installations with lower labour costs and prices. No other accessories are needed.
For horizontal pipes, when the process connection is vertical, the 𝗩𝗜𝟱 is mounted as delivered, screwing the inlet (male or female) in the process and at the other end the pressure gauge or instrument (see drw. 1).
For vertical pipes, when the process connection is horizontal, the side plug provided must be removed and placed on the female outlet end. Then, mount the instrument on the 1/2″ female side connection (see drw. 2).
Operation:
Once the instrument is online, open completely the blocking valve to assure the backseat effectiveness. Thus, the PTFE (or Grafoil) seal does not remain under pressure. In normal operation, the block valve is open and the purge one is cosed.
To take out the instrument or check the zero, the block valve will have to be closed and the purge one opened to leave the pressure.
To check an instrument without taking it away, use the threaded purge to put a know signal, with the block valve closed.