Application
- Circular EXCONTROL CAV controllers of Type RN-Ex for the precise supply air or extract air flow control in constant air volume systems
- For use in potentially explosive atmospheres (ATEX)
- Mechanical self-powered volume flow control without external power supply
Simplified project handling by ordering based on nominal size
Special characteristics
- ATEX mark and certification
- ATEX equipment group II, approved for zones 1, 2, 21 and 22
- The volume flow rate can be set using an external scale; no tools required
High volume flow rate control accuracy
Useful additions
- Circular silencers CA (for Germany and Switzerland) and CAH (for EMEA)
Pipe silencer to be ordered separately
Construction features
- Circular casing
- Construction and materials comply with the EU directive for use in potentially explosive atmospheres (ATEX)
- Spigot suitable for circular ducts to EN 1506 or EN 13180
Spigot with insert bead for lip seal; (except RN-Ex-P1/80 not possible with insert bead/lip seal)
Materials and surfaces
Galvanised sheet steel construction
- Any installation orientation
Correct operation even under unfavourable upstream or downstream conditions (1.5 D straight section required upstream)
Classification
According to type examination certificate TÜV 05 ATEX 7159 X
- Casing made of galvanised sheet steel
- Interior parts, nominal sizes 3 – 5: stainless steel 1.4301, nominal sizes 6 – 16: galvanised sheet steel
- Polyurethane bellows
- Plain bearings with PTFE coating
- Leaf spring made of stainless steel
- Zone 1 and 2 (substance group gases): II 2 G c II T5 / T6Powder-coated (P1)
Zone 21 and 22 (substance group dusts): II 2 D c II T 80 °C
Nominal sizes
3, 4, 5, 6, 8, 10, 12, 16
Variants
- RN-Ex: ATEX volume flow controller in standard construction
- Casing made of galvanised sheet steel, powder-coated
- Interior parts, nominal sizes 3 – 5: stainless steel 1.4301, nominal sizes 6 – 16: galvanised sheet steel, powder- coatedStainless steel construction (A2)
- Casing made of stainless steel 1.4301
- Interior parts made of stainless steelFor demanding acoustic requirementsVariant with acoustic cladding (-D)
- RN-Ex-D: ATEX volume flow controller with acoustic cladding
Acoustic cladding cannot be retrofitted
Construction
- Galvanised sheet steel
- Acoustic cladding made of galvanised sheet steel
- Rubber seal for the insulation of structure-borne noise
- Lining made of mineral wool Mineral wool
- P1: Powder-coated surface, silver (RAL 7001)
A2: Stainless steel
Parts and characteristics
- Ready-to-commission controller
- Damper blade with low-friction bearings
- Bellows for vibration damping
- Cam plate with leaf spring
- Scale with pointer to set the volume flow rate setpoint
- Terminal point for equipotential bonding
- Enclosed ground cable (approx. 3 ft length)
- Aerodynamic functional testing of each unit on a special test rig before shipping
- Acc. to EN 13501, fire rating class A1, non-combustible
- RAL quality mark RAL-GZ 388
Harmless to health due to high biosolubility, according to TRGS 905 as well as EU Directive 97/69/EC
Standards and guidelines
- Directive 94/9/EC: Equipment and protective systems intended for use in potentially explosive atmospheres
- Meets the hygiene requirements of VDI 6022
Casing air leakage acc. to EN 1751, class C
Maintenance
Maintenance-free, as construction and materials are not subject to wear and tear
Accessories
- Lip seals on both ends (factory fitted)
Function
Functional description
The volume flow controller is a mechanical self-powered unit and works without external power supply. A damper blade with low- friction bearings is adjusted by aerodynamic forces such that the set volume flow rate is maintained within the differential pressure range.
The aerodynamic forces of the airflow create a closing torque on the damper blade. The bellows extends and increases this force while at the same time acting as an oscillation damper. The closing force is countered by a leaf spring that unrolls over a cam plate. The shape of the cam plate is such that a change in the differential pressure leads to an adjustment of the damper blade in a way that the volume flow rate is maintained almost exactly.
Efficient commissioning
The volume flow rate setpoint value can be set quickly and easily using the pointer on the external scale; no measurements are required.
The advantage over flow adjustment dampers is that there is no need for repeat measurements or adjustments by an air conditioning engineer. Should the system pressure change, e.g. by opening or closing of duct sections, the flow rates in the entire system will also change if flow adjustment dampers are used; however, this is not the case with mechanical self-powered volume flow controllers A mechanical self-powered controller reacts immediately and adjusts the damper blade such that the set constant volume flow rate is maintained.
Schematic Illustration of the RN-Ex
① Damper blade
② Bellows
③ Bellows inlet
④ Crossbar
⑤ Leaf spring
⑥ Cam plate
⑦ Volume flow rate scale lock
⑧ Volume flow rate scale
⑨ Lip seal
Specification Text
This tender text describes the general properties of the product. Texts for variants are generated by our Easy Product Finder design programme.
Volume flow controller in round design for constant volume flow systems in potentially explosive atmospheres, mechanically automatic, without auxiliary power, for supply air or extract air, in eight nominal sizes.
Controller ready for commissioning, consisting of the housing with smooth-running control damper, control bellows and external cam disc with leaf spring as well as components for equipotential bonding and explosion protection.
Volume flow controllers are factory-set to a reference volume flow (setting of the desired volume flow on site by the customer). Spigot with insert bead for lip seal, suitable for air ducts to EN 1506 or EN 13180.
Casing air leakage according to EN 1751, class C.
Special Characteristics
- ATEX mark and certification
- ATEX equipment group II, approved for zones 1, 2, 21 and 22
- The volume flow rate can be set using an external scale; no tools required
- High volume flow rate control accuracy
- Any installation orientation
- Correct operation even under unfavourable upstream or downstream conditions (1.5 D straight section required upstream)
Materials and surfaces
Galvanised sheet steel construction
- Casing made of galvanised sheet steel
- Interior parts, nominal sizes 3 – 5: stainless steel 1.4301, nominal sizes 6 – 16: galvanised sheet steel
- Polyurethane bellows
- Plain bearings with PTFE coating
- Leaf spring made of stainless steel Powder-coated (P1)
- Casing made of galvanised sheet steel, powder-coated
- Interior parts, nominal sizes 3 – 5: stainless steel 1.4301, nominal sizes 6 – 16: galvanised sheet steel, powder- coatedStainless steel construction (A2)
- Casing made of stainless steel 1.4301
- Interior parts made of stainless steel Variant with acoustic cladding (-D)
- Acoustic cladding made of galvanised sheet steel
- Rubber seal for the insulation of structure-borne noise
- Lining made of mineral wool Mineral wool
- Acc. to EN 13501, fire rating class A1, non-combustible
- RAL quality mark RAL-GZ 388
- Harmless to health due to high biosolubility, according to TRGS 905 as well as EU Directive 97/69/EC
Construction
- Galvanised sheet steel
- P1: Powder-coated surface, silver (RAL 7001)
- A2: Stainless steel
Technical data
- Nominal sizes: 3 to 16 in
- Volume flow rate range: 23 – 2966 cfm
- Volume flow rate control range: approx. 25 – 100 % of thenominal volume flow rate
- Minimum differential pressure: 0.20 in wg (nominal size 3: 0.40 in wg)
- Maximum permissible differential pressure: 4.02 in wg
