13
2.3 SF
6
Sensor Mounting
Pipe Thread
INCON offers an SF
6
density sensor as an accessory to
the
OPTI
mizer²
: The
Model DSDP
with digital output
signal. This sensor uses a G 3 / 8” British Standard parallel
pipe thread with an O-ring seal. An appropriate adaptor
fitting will be required when installing one of these sensors
into a manifold or vessel with a different thread.
Other brands of SF
6
density sensor are available
with many other pipe thread options. Be sure you are
combining the appropriate sensor threads with the
appropriate adaptor fitting threads.
Location
It is always preferable that the SF
6
density sensor be
mounted as close to the gas vessel as possible, so that the
sensor can be close to the same temperature as the vessel.
The INCON DSDP is a “true density” sensor, not a
temperature-compensated pressure sensor. For this
reason, it is less critical that it be mounted as close as
possible to the SF
6
gas vessel. The density measurement
is not as affected by temperature.
Other brands of SF
6
density sensor may be used. Virtually
all other brands are temperature-compensated-pressure-
type sensors. It is more critical to mount this type of sensor
as close as possible to the SF
6
gas vessel, so that the
temperature of the SF
6
gas can properly affect the sensor.
A difference in temperature between the SF
6
gas in the
vessel and a sensor of this type will cause an error in the
density output signal.
The SF
6
density sensor may be installed alongside an
existing SF
6
density switch or gauge. If only one opening
is available, a “T” fitting may be used to create a second
opening for the sensor.
Any air in the piping to the sensor can delay accurate
density measurement for up to two weeks. The sensor
should be installed with the gas port facing upward if
possible. A SMALL amount of SF
6
can be bled past the
sensor threads before tightening the sensor to purge
trapped air.
Extreme care must be taken when
installing sensors. A gas-tight seal
must be achieved on all pipe fitting and
sensor threads.
Vacuum
If a vacuum is used to extract air before filling a breaker
with SF
6
gas, do not expose the density sensor to vacuum
greater than one atmosphere.
1
2
3
4
Viewed from end
SF
6
Sensor Connections
Pin 1: Connect to Opti
mizer
²
+ Terminal (Red Wire)
Pin 2: Connect to Opti
mizer
²
— Terminal (Black Wire)
Pins 3 & 4: No Connection
1.06" Dia.
(27 mm)
2.00"
(50.8 mm)
1.135"
(28.8 mm)
3.24"
(82.3 mm)
0.454"
(11.5 mm)
G ⅜" Thread
Figure 4: DSDP Sensor Connections
Caution
