Document P/N:
2A44778_SVC_MNL
Release Date:
07/29/2019
Revision: 1.0
7 of 23
Prior to operation, the user enters a
Pop-Off Set point
and a
Reset Pressure
. The
Pop-Off Set point
is the highest pressure that the
system will allow before actuating the relief system. If the wellhead pressure exceeds this value, the N
2
Relief Valve vents and relieves
pressure in the line until the reset conditions are met. The
Reset Pressure
is set below the
Pop-Off Set point
to ensure successful
reseating and protect the valve.
Example Operation Cycle
To prevent unintended pop-offs, a pop-off event occurs only when the treating pressure has exceeded the
Pop-Off Set point
for a period
of time. The time period is configurable and is referred to as
Pop-Off Filter.
It is typically set to 100 ms (see Pop-Off Detail).
Pop-Off Detail
2.1 Venting and Reset
When a pop-off event occurs, the relief valve’s nitrogen chamber is emptied so that the valve can open fully. Strobe lights on the valve
box alert operators that the valve is venting. Once a pop-off event has been triggered, the valve continues to vent until two reset
conditions are satisfied. Reset condition 1 requires the treating pressure to remain below the
Reset Pressure
for a minimum amount of
time. The time period is referred to as
Reset Filter
and is typically set to 100 ms (see Reset Condition 1 Detail). Reset condition 2
requires that, once the valve begins venting, it does not reseat for a minimum amount of time (referred to as Minimum
Pop off Time
and typically set to 2 s). The reset conditions can be satisfied in either order.
Reset Condition 1 Detail
SECTION II: Operation
