KROHNE ALTOSONIC III EN - Manual (Page 27)

Installation and operating instructions
27 ALTOSONIC III
5. Installation in
hazardous
areas, zone 1
and zone 2
5.1 Approvals The ALTOSONIC III ultrasonic flowmeters in compact and separate design are in accordance with the European
Directive 94/9 EC (ATEX 100a) and approved for hazardous classified locations of Zone 1 and 2 by the PTB conform to
the European Standards of the EN 500xx series, approval number: PTB 03 ATEX 2021 X.
5.2 Compact flowmeter The standard ALTOSONIC III C-EEx compact flowmeter is designed for ambient temperatures (i.e. Ta) in the range of
-40°C / 104°F up to +70°C/158°F. The maximum allowed process liquid (medium) temperature is restricted by the
combustible atmosphere that (possibly) surrounds the apparatus, determined by the temperature class of the
atmosphere, see table below.
Temperature class Maximum process liquid temperature at
Ta ≤ 40°C / 104°F Ta ≤ 50°C / 122°F Ta ≤ 60°C / 140°F
T6 80°C / 176°F 80°C / 176°F 80°C / 176°F
T5 95°C / 203°F 95°C / 203°F 95°C / 203°F
T4 130°C / 266°F 130°C / 266°F 125°C / 257°F
T3 180°C / 356°F 165°C / 329°F 125°C / 257°F
The ALTOSONIC III K/…-EEx compact flowmeter consists of the UFC III…-EEx flow converter that is screwed on top of
the UFS III-EEx flow sensor by four hexagonal socket head cap screws of size M6. The standard compact flowmeter is
marked with one of the codes below:
Standard: II 2G EEx de [ib] IIC T6…T3 for the terminal compartment of the flow converter housing in type of protection
increased safety "e" according to EN 50019.
Optional: II 2G EEx d [ib] IIC T6…T3 for the terminal compartment of the flow converter housing designed as
flameproof enclosure "d" according to EN 50018.
5.3 Flow sensor The UFS III…-EEx flow sensor is the measuring unit of the ALTOSONIC III (3-beam) ultrasonic flowmeters. It contains
the ultrasonic sensor (three pairs of opposite transducers) in type of protection intrinsic safety category "ib" according to
EN 50020. All sensor circuits are wired by separate coaxial cables and connected through SMB connectors, which are
marked by the respective numbers 1.1, 1.2, 2.1, 2.2, 3.1 and 3.2. The flow sensors are available in size DN25 (1”) up to
DN1000 (40”) in diameter.
The UFS III…-EEx flow sensor is used in combination with the flow converter unit type UFC III…-EEx, which is either
directly mounted on top of the flow sensor (compact meter) or installed on a distance and connected via a cable
(separate version). In the last case the flow sensor as well as the flow converter unit are both provided with a junction
box, in which the SMB connectors are mounted.
The UFS III F/…-EEx flow sensor in separate design is the measuring unit of the separate flowmeter system. The
sensor is suitable for process liquid temperatures from -25°C/-13°F up to +180°C/356°F and designed for an ambient
temperature in the range of -40°C/-40°F up to +70°C/158°F.
The UFS III F/…-EEx flow sensors in separate design are classified according to the temperature classification table
below.
Temperature class Maximum process liquid temperature at Ta = 60°C / 140°F
T6 80°C / 176°F
T5 95°C / 203°F
T4 130°C / 266°F
T3 180°C / 356°F
The UFS III F/…-EEx flow sensors are marked with the explosion safety codes: UFS III F-EEx: II 2G EEx ib IIC T6…T3.
The intrinsically safe "ib" ultrasonic sensor circuits inside the UFS III…-EEx flow sensor have the following maximum
values (i.e. entity parameters):
Maximum input voltage : V
max
= 13.1 V