Special Condition Moist Sample Gas; Electrical Connections - Bühler technologies P2.3C Guía Rápida

P2.3C, P2.4C

4.3 Special condition moist sample gas

Applications where the sample gas is still moist may result in
condensate forming in line and the pump body. In these
events the pump head must be suspended (pump body facing
down).
If the pump was not ordered this way, it can easily be conver-
ted on site.
Install the line between the gas output and condensate drain
with a grade so the condensate can drain and does not collect
inside the pump or the lines.
4.4 Connecting the gas tubes
The pumps are delivered with customized gas connections.
Please compare the part-no. on the type plate with the part-
no. explained in chapter "Introduction".
Avoid mixed installations, that is connecting metal tubes to
plastic bodies. If this is unavoidable for sporadic applications,
screw the metal fitting with utmost care and without any use
of force to the PTFE pump body.
Install the tubes in a way that the line at the inlet and outlet is
flexible over a sufficient distance (pump vibrates).
The pumps are marked with "In" for inlet (input) and "Out"
for outlet (output). Make sure that the connections to the
tubes are tight.
4.4.1 Monitoring the sample gas pump
NOTICE
When following preventive maintenance according to the
maintenance plan, a crack in the bellows is a rare malfunc-
tion, but cannot be completely eliminated.
NOTICE
If the bellow cracked, turn the pump off immediately!
NOTICE
If flammable gases (even above upper explosion limit (UEL))
or toxic gases are supplied, continuous monitoring of the
pump is mandatory.
DANGER
Explosion hazard, danger of poisoning!
A crack in the bellows when conveying flammable or poison-
ous gasses may allow explosive or poisonous gas mixtures to
leak or develop.
Monitor the pump with a flow- and/or vacuum monitoring
system (see flow diagram).
If a pump defect occurs, shut it off immediately.
4.4.1.1 General monitoring measures
Since a crack in the bellow allows the ambient atmosphere to
be sucked in and the sample gas pump continues to generate
pressure, the bellows of the sample gas pumps must be in-
spected regularly.
In addition, the flow rate of the pump (to the sample gas out-
let) must be monitored with a suitable flow meter.
12 Bühler Technologies GmbH
For more information or Inspecting the bellow the mainten-
ance schedule, please refer to the chapter Maintenance at the
end of the operating and installation instructions.
4.4.1.2 Monitoring measures when conveying
flammable and/or toxic gasses
Conveying flammable and/or toxic gasses further requires
continuous monitoring of the sample gas pump during oper-
ation. This can be done as follows (1) or (2).
1. Flow rate monitor before the pump's gas inlet and after
the gas outlet. A sudden reduction of the suction
volume / flow volume ahead of the pump and consistent
or suddenly increased flow volume after the pump indic-
ates a defective bellow (the pump can convey ambient air
suctioned in due to the tear).
2. Vacuum monitoring before the pump's gas inlet and flow
monitoring after the gas outlet (see illustration). A sud-
den drop in the vacuum before the gas inlet indicates a
defective bellow.
When conveying flammable gasses above the upper explosive
limit (UEL) we further recommend monitoring the lower ex-
plosive limit (LEL) in the installation location.
When conveying toxic gasses we recommend MAC monitoring
(MAC: Maximum Workplace Concentration) at the installation
site.
underpressure
manometer
shut-off valve
sample gas pump
Fig. 1: Sample flow diagram of suitable monitoring

4.5 Electrical connections

WARNING
Hazardous electrical voltage
The device must be installed by trained staff only.
CAUTION
Wrong mains voltage
Wrong mains voltage may damage the device.
Regard the correct mains voltage as given on the type plate.
A switch or circuit breaker (per approval) must be installed for
the sample gas pump. It must be easy for the operator to
reach. The switch must be marked as a cut-off for the device. It
mustn't be integrated into a supply cable or interrupt the
earth conductor. It must further separate all poles of the
sample gas pump from live parts.
The sample gas pump must be protected against prohibited
heating with suitable overload protection (protective motor
switch per approval).
Please note the rated current for the protective switch set-
tings (see motor type plate).
manometer
flowmeter
BX420022 ◦ 04/2021