Yokogawa DM8C/VD6 Liquid Density Analyzer - Manual (Page 22)

< 1. GENERAL >
1-12
IM 12T03A01-02E
1.4.3 Installation Area and Ambient Conditions
Model VD6DF density detector can be installed in hazardous area where specifi ed gases are present.
However, do not install the detector at the place where explosive gases may be continuously present,
and in which the gas concentration is continuous or for long period, equal to or more than, the lowest
gas explosion limit.
Environmental conditions at the installation site are very important to the detector.
Before installing the detector, check the temperature, humidity and altitude of the site.
The conditions shall not exceed the specifi ed ranges. The temperature range (-10 to 50 °C) in
indicated on the data plate, and the altitude shall be 1000 meters or less above sea level and the
relative humidity range 45 to 85 %.
1.4.4 External Wiring Work
External wiring for fl ameproof detector shall be carried out according to the fl ameproof metal conduit
wiring. For TIIS explosionproof specifi cations, the fl ameproof packing type is used for leading external
cables.
1.4.5 Maintenance Procedure
Do not remove the detector cover in a hazardous area unless power is OFF. However, if detector
maintenance with power on is unavoidable, a gas detector check should fi rst be made to determine
whether a hazardous atmosphere exits in the installation area.
1.4.6 Repairs
The following points must be observed during repairs.
The detector must be restored to their original conditions, electrically and mechanically to maintain
their fl ameproof properties.
The gaps, path lengths and mechanical strength of enclosures are important factors in establishing
fl ameproof properties. Therefore, service staff should be careful not to damage point surfaces and not
to shock enclosures.