Honeywell HON 673 User Manual

Basics for installing the device in a pipe
HON 380 gas pressure regulator with HON 673/674 controller 26
4.3 Operating and measuring lines
The lines must be arranged and sized in such a way that the devices’ intended
function will be ensured.
 Measuring line
 The measuring line transmits the pressure process value from the
sensing point to the measuring diaphragm of a controller or the pi-
lot of a gas pressure regulator or safety relief valve or to the measur-
ing diaphragm of the monitoring device of a slam-shut device. It
needs to be connected to the pipe sideways or upwards separately
for each device. In the case of safety equipment, the measuring line
must be connected upstream of the first outlet-side shut-off device
in such a way that it cannot be shut off. If the measuring line is addi-
tionally connected downstream of the first outlet-side shut-off de-
vice, 3-way ball valves with negative overlap must be used for
switching. These ball valves do not have a valve position in which
both measuring lines can be fully closed at the same time.
 Vent line
 The vent line is used to connect a measuring diaphragm to the at-
mosphere. If the measuring unit becomes damaged (e.g., dia-
phragm rupture), it can start conveying gas. Under certain operating
conditions, and following consultation with the manufacturer, vent
lines can be omitted if vent valves (HON 915) or safety diaphragm
configurations can be used instead.
 Blowdown line
 The blowdown line in a safety relief valve is used to divert gas (leak-
ing gas, for example) into the atmosphere.
 Grouping vent lines or blowdown lines (into a header) is permissible
if it does not have a negative impact on the individual devices’ oper-
ation. Within this context, it is recommended to have the cross-sec-
tional area of the header be at least five times as large as the total of
the individual lines’ cross-sectional areas.
 For primary slam-shut devices, it is recommended to route the
slam-shut devices’ vent lines separately. Vent lines must not be
grouped together with blowdown lines.
 Discharging line
 When using indirect acting (pilot-operated) slam-shut devices, the
discharging line is used to divert the exhaust gas from the pilot into
the system’s outlet chamber. On certain devices, the discharging
line will be grouped with the feedback line.
 Feedback line
 When using indirect acting (pilot-operated) slam-shut devices, the
feedback line is used to return the outlet pressure to the actuator.
Connection lines be-
tween device and gas
regulating line

Honeywell HON 673 Specifications

General

Brand	Honeywell
Model	HON 673
Category	Controller
Language	English