VACUUBRAND RC 6 - Manual (Page 29)

page 29 of 59
Avoid high heat supply (e.g., due to hot process gases).
See “Technical data”, pg. 19, for maximum permitted
gas and ambient temperatures.
A warm up period (approximately 30 min.) is required to
ensure that the rated ultimate vacuum and pumping speed
as well as the full vapor pumping rate and chemical resis-
tance of the pump are attained. To warm up the pump
effectively before connecting to the vacuum application,
install a shut-off valve (see ”Accessories”, pg. 39).
The attainable ultimate vacuum is limited by the properties
of the vacuum vessel (leak-tightness, cleanliness and de-
gassing of the inner surfaces), degassing of substances
used and the condition of the pump oil (cleanliness, con-
tent of hydrocarbons with higher partial pressures).
Use the manometer monitoring the pressure in the oil
reservoir of the HYBRID pump to check the operability of
the diaphragm pump. If during the process the pressure
inside the oil reservoir should rise significantly (manome-
ter needle clearly in the red zone), it is necessary to take
appropriate measures to reduce the inlet pressure.
For the HYBRID principle to work it is necessary to
prevent the pumped vapors from condensing inside
the oil reservoir. Therefore the pressure inside the
oil reservoir has to be lower than the vapor pressure
of the pumped media at the oil’s temperature (140°F
(60°C)). If necessary, the volume of pumped vapors
has to be reduced or a cold trap has to be installed.
If no improvement is achieved even with the vacuum
chamber being absolutely leak tight, this points to a po-
tential failure of the diaphragm pump, e.g., a diaphragm
crack. A more accurate check of the pressure inside the oil
reservoir is possible with a more precise manometer, e.g.,
a DVR 2 digital vacuum gauge. If a pressure higher than
19 Torr (25 mbar) is measured with inlet port and gas bal-
last valve closed, check the diaphragm pump and replace
the diaphragms if necessary.
Any drop in the diaphragm pump’s pumping speed pro-
duces a pressure increase in the oil reservoir. Although