The digital pressure gauge and manometer DMU-JB is a battery-operated handheld service and workshop instrument, intended for wide use in industry, power engineering, heating and combustion technology, air-conditioning, ventilation, laboratories, etc. Its qualities especially come out compared with liquid column manometers (U-tubes). The DMU-D instrument is used for measuring pressure differences at corresponding pressure which is comparable with the nominal range. It is not possible to measure pressure differences at high corresponding pressure, eg. on flow plates in gas pressure distribution systems. For these measuring is intended the DMU-P instrument, which enables measuring of pressure differences on the static pressure up to 100 times higher than the nominal differential pressure, but max. 1MPa. When one of the pressure inputs is not connected, the instruments measure relative overpressure or underpressure against the atmospheric pressure. The measured medium can only be non-aggressive gas, eg. air, nitrogen, etc. The DMU gauges, version JB are spark secure types marked I M1 Ex ia I Ma, which can be used in mines with occurrence
of methane and/or flammable dust or marked II 2G Ex ia IIAT4 Gb, which can be used in areas with explosive gas atmosphere (Zone 1).
The instrument is mounted into a plastic casing from ABS. An inseparable part of the spark secure version is a leather case. The instrument is controlled by means of buttons on a folio keyboard which enable switching on//off the instrument, possible zero correction and switching on the time filter, which enables reading the mean value at the pulsating pressure on the input. Inlets with the external diameter 5 mm are used for connecting the pressure of the medium. Digital data about the measured pressure are displayed on a 3.5-figure LCD display in Pa or kPa with differentiability 0.1% from the nominal range. A positive value corresponds with overpressure, a negative one to underpressure, at differential measuring a positive value corresponds with higher pressure on the positive pressure input. The instrument can be used for measuring pressure up to 200% of the nominal pressure range. Based on an agreement, it is possible to supply DMU instruments calibrated also in other pressure units.
