- Exclusive UK and Ireland Rixen Messtechnik representative
- Hazardous-area configuration guidance
- Ex-zone, output and limit contact support
Rixen Messtechnik RW65_EX_II Intrinsically Safe Ringbalance Differential Pressure Gauge
ATEX intrinsically safe Ringbalance gauge for hazardous-area low-pressure monitoring with local indication and passive 4–20 mA output.
Key highlights
- Intrinsically safe: ATEX approved for gas and dust hazardous areas
- Ex-zone suitability: Approved for zones 0, 1, 2, 20, 21 and 22
- Local indication: Large 150 x 150 mm analogue dial for on-site reading
- 4–20 mA output: Passive transmitter output for remote signal transmission
- Biogas applications: Suitable for gas accumulator and anaerobic digestion monitoring
- Configuration options: Measuring range, scaling, housing and limit sensor options selected to suit the duty
The Rixen Messtechnik RW65_EX_II is an intrinsically safe Ringbalance differential pressure gauge for hazardous-area low-pressure monitoring. It combines local analogue indication with a passive 4–20 mA transmitter output for applications where pressure measurement is required in Ex-zone environments.
As an ATEX differential pressure gauge for gas and dust hazardous areas, the RW65_EX_II is approved for gas zones 0, 1 and 2, and dust zones 20, 21 and 22. Its ATEX marking is II 1G Ex ia IIC T4 Ga and II 1D Ex ia IIIC T135°C Da.
The instrument is particularly relevant for biogas, anaerobic digestion and gas accumulator pressure monitoring. Rixen Messtechnik’s product material discusses pressure monitoring in anaerobic digestion plant reservoirs where methane, carbon dioxide, hydrogen sulphide and other gases may be present.
Using the Ringbalance measuring principle, the RW65_EX_II provides local pressure indication through a large analogue dial while also supporting remote signal transmission via its intrinsically safe passive 4–20 mA output. This allows the instrument to support both visual checks and connection to a suitable control or monitoring system.
Measuring range, scaling, housing material, output configuration, limit sensor requirements and overload protection should be reviewed before ordering. Optional NAMUR inductive limit contacts and DZ overload protection may be considered where switching duties or overload conditions are expected.
Key Features
- Intrinsically safe Ringbalance gauge: Provides low draft, pressure and differential pressure measurement for hazardous-area applications.
- ATEX gas and dust approval: Approved for gas zones 0, 1 and 2, and dust zones 20, 21 and 22 with II 1G and II 1D marking.
- Local analogue indication: Large 150 x 150 mm dial supports direct pressure reading at the instrument.
- Passive 4–20 mA output: Intrinsically safe transmitter output supports remote pressure monitoring through suitable Ex signal equipment.
- Hazardous-area application focus: Suitable for applications such as biogas, anaerobic digestion and gas accumulator pressure monitoring.
- Freely selectable range and scaling: Measuring range and scale can be selected to suit the required low-pressure duty.
- Optional limit sensing: NAMUR inductive limit contacts can be specified where minimum or maximum switching functionality is required.
- Overload protection option: DZ1 or DZ2 overload protection can be considered where excessive differential pressure may occur.
Specifications
| Measurement | |
| Product Type | Intrinsically safe Ringbalance differential pressure gauge with passive transmitter output |
| Model | RW65_EX_II |
| Measurement Duties | Draft, pressure and differential pressure |
| Display | Large analogue dial, 150 x 150 mm |
| Measuring Range | All combinations between ±20 Pa and ±1,800 Pa |
| Scale Selection | Freely selectable scaling, including Pa, mbar, mmWS, in.W.C., kPa, daPa and mmCE |
| Accuracy | Maximum error ±1.5% FS, or ±1.5 Pa |
| Ambient Temperature | -20 °C to +50 °C |
| Hazardous-Area Approval | |
| Certificate | OBAC 17 ATEX 0166 |
| Certificate Product Description | Ringbalance meter with 4–20 mA loop powered transmitter type RW 65 EX II |
| ATEX Category | II 1 GD Ex ia IIC/IIIC T4 Ga Da |
| Gas Marking | II 1G Ex ia IIC T4 Ga |
| Dust Marking | II 1D Ex ia IIIC T135°C Da |
| Gas Zones | 0, 1 and 2 |
| Dust Zones | 20, 21 and 22 |
| Intrinsically Safe Parameters | Ui = 29 V; Ii = 107 mA; Pi = 620 mW; Li and Ci negligible |
| Output and Signal Options | |
| Transmitter Output | 4–20 mA passive |
| Supply | 11–30 V DC via Zener barrier / isolating amplifier |
| Safe-Side Interface | Zener barrier or isolating converter required on the safe side |
| Optional Limit Sensor Function | Up to 2 optional NAMUR inductive contacts; no MK contacts in Ex zone |
| Limit Contact Integration | Requires suitable certified switching amplifier or intrinsically safe NAMUR input |
| Housing and Construction | |
| Dimensions | 235 x 195 x 165 mm (H x W x D) |
| Housing Options | Steel RAL 5015 or stainless steel |
| Housing Protection | IP65 for steel housing; IP66 for stainless steel housing |
| Connection | 8 mm nozzles |
| Mounting | Wall-mounted housing |
| Overload Protection | |
| Inherent Protection | Ringbalance instruments are inherently protected to at least ±900 Pa with mineral oil filling |
| Synthetic Oil Protection | With synthetic oil filling, inherent protection is up to approximately ±2 kPa |
| DZ1 Option | Overload protection for applications where connection polarity is observed |
| DZ2 Option | Two-sided overload protection where pressure inversion may be possible |
| Overload Note | Overload conditions should be stated during specification and ordering |
| Ordering and Configuration | |
| Required Configuration | Measuring range, scale, housing material, output / limit function and overload protection requirements |
| Included Documentation | Factory calibration and Declaration of Conformity included |
| Installation Note | Installation and Ex signal integration must be carried out by suitably qualified personnel |
| Application Review | Hazardous-area classification, gas / dust zone, signal interface and process conditions should be reviewed before quotation |
Support
Able Instruments are Rixen Messtechnik’s Exclusive Representative for Sales and Service in the UK and Ireland, providing application and configuration support for hazardous-area low-pressure monitoring applications.
- Hazardous-area review: Advice on whether the RW65_EX_II is suitable for the required gas or dust Ex-zone application
- Range and scale selection: Support selecting the correct low-pressure measuring range and dial scaling
- Signal integration: Guidance on passive 4–20 mA output, Ex separation and suitable control system interface requirements
- Limit contact options: Support reviewing NAMUR inductive limit contact requirements where min / max switching is needed
- Overload protection: Advice on whether DZ1 or DZ2 overload protection should be considered where pressure spikes or pressure inversion may occur