ATEX UNLOADER AND RELIEF VALVES
SAFETY NOTE
SN03
Rev. 00
Date 27/10/2020
Pag. 6 of 10
3.3.1 CONNECTION & SETTING
The valve must be connected to a pressure application, usually fed by piston pumps, pressure washers and similar; in
order to prevent possible damage to persons and things, where such an application must be equipped with all safety
parts and control (like safety valves, regulating etc.) foreseen by the directives in force. Use a resistant and adequate
sized tube for the connection, possibly avoiding narrow necks and abrupt direction variations to restrain the pressure
loss.
The valve must be anchored firmly by an appropriate support. This type of valve must be held and fed by a fixed pipe
that prevents any swinging.
The connecting tube to the valve must be of such to help the fluid flow without any excessive pressure drop.
The assembler is compelled also to carry out the inspection of all the connection links.
The apparatus must be installed by the following procedure:
Assure that there is no obstacle placed between valve and attachment; place a suitable gasket that assures a
seal age conform and a protection grade minimum IP54 for Gas and IP6X for powders.
Insert the connection tubes (entry and exit) following a good technique and using acknowledged
components, adopting the foreseen clamping instructions.
During the connection of the tubes, make an electrical earth link-up with a minimum cable size 4mm
observing the prescribed terms for equipotential connections.
Inspection after installation, to be carried out by the assembler or end user, in particular the perfect coupling
of usage at the various openings (keep to the limit levels of emission rated in the zoning phase).
3.4 USE & WORKING
3.4.1 WORKING & ADJUSTMENT
The function of the unloader valve is to prevent the risk of overpressure by automatically releasing the overpressure
towards the by-pass line when the pressure exceeds the set value.
The function of the relief valve is to discharge excess fluid to the inlet system when the pressure of the protected
equipment exceeds the maximum allowable pressure values for expressly non-ordinary reasons of operation
(incorrect maneuver with excess pressure and excess temperature, also caused by external fire).
This function takes place with the direct discharge into the atmosphere without the need for drainage with the direct
discharge pipe into the atmosphere, or with recycling in the collection and replenishment system water tank.
The valves intent is to be assembled into a set whose destination has industrial, technological and production
purposes.
The procedures to observe during function concern the process levels and correct running.
3.4.2 SUITABLE & NON-SUITABLE USE
The cleaning liquid should have an ignition temperature of minimum 50K over the maximum exterior temperature of
the appliance's surface where the cleaning liquid is utilized. (T=70 °C).
It is forbidden to make substantial modifications to the valve (replacement of parts not recognized by P.A. S.p.A. or
assembly variations). In the other cases of ordinary & extraordinary maintenance and repairs, refer to the
maintenance manual.
