GAS 222.11
4.7 Connecting the Blowback and Pressure Vessel
(Optional)
The air lines must be connected carefully and properly, using
suitable fittings.
If the probe is equipped with pressure vessel for efficient
blowback (optional), a manual shut-off valve (ball valve) must
be installed in the air supply, immediately upstream from the
pressure vessel.
On probes used to sample flammable gas, nitrogen (inert gas)
must be used for blowback. Blowback of explosive gases is
prohibited.
NOTICE
The operating pressure of the compressed air (inert gas) re-
quired for blowback must always be higher than the process
pressure.
Required pressure differential min. 3 bar (44 psi).
DANGER
Broken pressure vessel
Gas leak, danger due to flying parts.
Maximum operating pressure of the pressure vessel 10 bar
(145 psi)!
The operating pressure reduces based on the operating
voltage (see solenoid valve type plate).
DANGER
Adiabatic compression during gas blowback (explosion
hazard)!
Adiabatic compression may cause high gas temperatures and
must be checked by the user.
Gas blowback may result in high gas temperatures due to
adiabatic compression. This can cause flammable gases to ig-
nite spontaneously.
a) Blowback of explosive atmosphere / gases is prohibited.
b) Flammable atmosphere / gases (non-explosive) may only
be blown back with nitrogen (inert gas).
4.8 Electrical Connections
DANGER
Explosion hazard due to absence of potential equalisa-
tion
The device must be connected to potential equalisation
(earthed) at the designated points.
Please observe the local regulations and guidelines.
CAUTION
Wrong mains voltage
Wrong mains voltage may damage the device.
Regard the correct mains voltage as given on the type plate.
BX460037 ◦ 09/2021
Atex valves only:
DANGER
Explosion hazard when opening the solenoid valve
housing
The solenoid valve is a closed system. It must not be removed!
A fuse suitable for the rated current (max. 3 x Ib per
IEC 60127-2-1) or a protective motor switch with short circuit
and fast thermal response (set for rated current) must be con-
nected upstream from each magnet to prevent short-circuits.
• For magnets with a very low rated current, a fuse of the
lowest current value under the IEC standard will suffice.
This fuse must be connected separately, upstream.
• The rated fuse voltage must be equal to or greater than
the specified nominal voltage (U
The fuse rating is specified in the type plate of the solen-
oid valve.
• The limiting breaking capacity of the fuse element must
be equivalent to or greater than the maximum short-cir-
cuit current expected at the installation site (typically
1500 A).
4.8.1 Heated Pressure Vessel (Optional)
A heated blowback vessel may optionally be used for blow-
back. Heated via self-regulating PTC heating cartridge to pro-
tect against frost.
The electrical connection (mains connection 115/230 V AC)
uses a cubic plug as per DIN 43650. Please refer to the ter-
minal diagram at the end for the connection.
• Only use cables with a temperature resistance of > 100 °C
to connect to power.
• Make sure the connecting cable has sufficient strain relief
(match cable diameter to the seal on the socket).
• When connecting, also observe the applicable Ex protec-
tion regulations and general warnings in these operating
instructions.
CAUTION
Equipment damage
Cables damaged
Do not damage the cable during installation. Install a strain
relief for the cable connection. Secure the cable against twist-
ing and loosening. Please note the temperature resistance of
the cables (> 100 °C/212 °F).
DANGER
Adiabatic compression during gas blowback (explosion
hazard)!
Adiabatic compression may cause high gas temperatures and
must be checked by the user.
Gas blowback may result in high gas temperatures due to
adiabatic compression. This can cause flammable gases to ig-
nite spontaneously.
a) Blowback of explosive atmosphere / gases is prohibited.
b) Flammable atmosphere / gases (non-explosive) may only
be blown back with nitrogen (inert gas).
+10 %) of the magnet.
N
Bühler Technologies GmbH
11