REV
.
04
02-12-2019
INSTALLATION
,
USE AND MAINTENANCE MANUAL
–
PNR/E 73-83-104-124
–
PNR 142
17 / 44
Jurop
SpA
Via Crosera n° 50
33082 Azzano Decimo, PN (Italia)
T
EL
.
+39
0434
636811
F
AX
.
+39
0434
636812
http://www.jurop.it
e-mail: [email protected]
flanged version (without manifold with 4-way valve and non-return vale),
it is advisable to intercept the working line of the machine when it is
stopped, to prevent contrary rotations until the rebalancing of the
pressures. The interception can take place through a controlled valve or
an automatic unidirectional valve (swing valve).
• Avoid starting the pump under load: motor and drive system can be
excessively stressed.
• With temperature below 5 °C (40 °F) and long periods of inactivity,
introduce some quantity of oil through the suction connection before
starting off the pump.
• The air injection cooling system grants the use of the vacuum
pump at high vacuum rates. Anyway it has to be remembered that the
pump has been designed for non-continuous work. This cooling system
allows to dissipate part of the accumulated heat still at satisfactory
lubrication conditions. Continuous, heavy-duty work, or prolonged work
periods will cause an over-heating of the pump, consequently reducing
performances and durability.
• With the PNR models it is quite normal that the vacuum rate in the
tank will fall down at about 50%, if and when the pump is stopped for
sufficient time. This because atmosferic air will flow back in the tank
through the injection valves, which are adjusted at approximately 0,5
bar. Vent the tank and take it to atmospheric pressure when stopping
the pump in order to avoid back rotation of the pump.