Atex Safety Measures - VERDER Packo ZP Series Instruction Manual

2.2 ATEX SAFETY MEASURES

Pump
type
Liquid
Non ignitable
liquid
Ignitable liquid
The flashpoint of a combustible liquid is the lowest temperature at which sufficient vapor is created
above a combustible liquid so that it can ignite when mixed with air. However, be aware that the
temperature of certain spots on the pump (e.g. the mechanical seal or motor) could be warmer than
the temperature of the circulated liquid. Therefore, if the flashpoint of the liquid is above the
temperature the liquid is pumped but below 135°C, it should also be considered as ignitable when
considering the risk leakage.
Please be aware that if a mechanical seal runs dry, the temperature of the seal faces can rise above
400°C.
Pumps with flushed mechanical seal:
You have to make sure there is a continuous circulation of the flushing liquid and the motor is
stopped immediately in case of lack of flushing liquid. Otherwise the mechanical seal can run
dry and generate dangerous high temperatures. When a quench reservoir is applied, the level
of the flushing liquid in the quench reservoir must be guarded by an ATEX approved level
sensor. If the level becomes too high or too low, the pump must be stopped. The temperature
in the quench reservoir should be guarded by an ATEX approved temperature sensor. The
temperature of the flushing liquid should be kept below 60°C. If necessary an external cooling
system should be used to keep the flushing temperature under 60°C. It is the responsibility of
the end user to use a suitable flushing liquid for the mechanical seals. The mix of the flushing
liquid and the pumped liquid must not create any dangerous or explosive gasses.
The pump should never run with closed valve.
Pumps with single mechanical seal:
You must monitor the flow (e.g. with an ATEX approved flow sensor on the inlet of the pump).
If there is no flow detected, you must stop the motor immediately.
Leakage of an ignitable liquid is a serious safety risk. The end-user has to evaluate the
consequences of the leak and adjust the check frequency for leak of the mechanical seal. In
case leak is detected, the pump must be stopped and the mechanical seal has to be replaced.
The mechanical seal has to be replaced preventively every 3000 operating hours.
The baseplate of the pump must be earthed in order to prevent a build-up of static
electricity.
The pump must not pump liquids warmer than 108°C.
The pump should not be started before compliance with all these safety measures.
9
Risk Dry running of mechanical
seal
(overheated seal faces are an
ignition source)
• Flushed mechanical seal
• or flow monitoring to be
installed by the customer
Leakage
(inflammable liquid can come into the
atmosphere)
No danger
• Flushed mechanical seal
• or single seal with preventive
maintenance by the customer