Safety Device At The System Delivery; By-Pass Valve - VARISCO V-ATEX Instructions De Sécurité

V-ATEX
- SAFETY INSTRUCTIONS IN ACCORDANCE WITH DIRECTIVE 2014/34/EU
Figure 3 indicates a diagram of the lubrication circuit and the application of the temperature probe.
If an external pressurisation system is connected for mechanical seals, the relative user and maintenance instructions must be
complied with.
9.2 PACKING SEAL
The packing seal must drip for it to function smoothly; in relation to the characteristics of the fluid and the operating parameters
of the pump, the seal must lose 10 to 100 drops per minute. The dripping lubricates the packing rings and eliminates the heat
generated by friction. The packing seal requires frequent adjustment to ensure proper dripping. For the adjustment of the gland,
refer to Par. 10.2 of the User and maintenance instructions.
The braided seal must be replaced when its tightness properties have reduced significantly. A pack that is too compressed,
hardened and dry causes wear on the shaft.
V Atex packing pumps can be supplied without flushing (SP version) or with flushing (SP1 version). In the first case, a probe can
be connected to monitor the seal temperature (Fig. 4.a); in the second case, (Fig. 4.b) it is not recommended to connect a probe
in this position, otherwise the temperature will not be monitored correctly.
Incorrect adjustment of the gland and/or inadequate connection of any temperature probe will invalidate the requirements
concerning safety and protection against the risk of explosion.
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SAFETY DEVICE AT THE SYSTEM DELIVERY

It is strictly essential to install a pressure limiting device downstream of the pump; it must be placed as close as possible to the
pump delivery but before any valve that may limit the flow. This component must be CE marked in accordance with Directive
2014/68/EU (PED) in category IV, as a safety device and in conformity to Directive 2014/34/EU.
The requirements concerning safety and protection against the risk of explosion are invalidated if the maximum pressure
safety device is missing or its characteristics do not correspond.
The operating pressure of this device must be taken from the efficiency curve of the pump relative to the rotation speed used
(Fig. 5): the calibration pressure (see instructions of the valve manufacturer) must be higher than the operating pressure of the
pump.
Incorrect calibration of the maximum pressure safety device invalidates the requirements concerning safety and
protection against the risk of explosion.
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BY-PASS VALVE

The by-pass valve is an optional accessory and if it is supplied, it is fitted on the pump (with the exception of V 25-2/V 30-2 K+R2,
in which case the valve must be fitted on the delivery pipe). The by-pass valve protects the pump (not the entire piping system)
if brief overpressure pulses occur. If the calibration pressure of the by-pass valve is exceeded, a part or all the flow is returned
to the pump suction: this way, liquid recirculation is generated inside the pump which can cause the liquid to heat significantly and
consequently, the pump. Do not use the by-pass valve to maintain constant pressure or flow at pump delivery. The calibration
pressure (see Par. 7.4 of the User and maintenance instructions) must exceed the operating pressure of the pump and in any
case must not allow any liquid to leak during regular pump operation, which could cause the superficial temperature of the device
itself to increase.
The by-pass valve must not trip for a prolonged period of time; long recirculation of liquid causes the liquid and the pump
to heat up, consequently invalidating the requirements concerning safety and protection against the risk of explosion.
The integrator/installer must guarantee the flow of process liquid.
If, following the process risk analysis, the integrator/installer decides to install a sensor to guarantee this condition, it must have
minimum safety function efficiency equal to PL=c, category=2, in accordance with UNI EN 13849-1:2008; this sensor must be
connected to the control panel and must stop the pump when the set threshold is reached. The connection must be carried out
by specialised personnel and in compliance with the regulations in force.
CAUTION
CAUTION
CAUTION
CAUTION
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