Single stage centrifugal biogas blowers MCF series

Centrifugal single stage biogas blowers

• Pressure differential up to 150 mbar (g)
• Flowrate up to 2,800 m³/h

Principle of operation

The MAPRO® centrifugal fans, MCF Series, are made of:

• An intake duct conveying the aspirated gas to the impeller inlet that is coaxial to the shaft
• A closed impeller with axial flow inlet and radial flow exit
• A toroidal discharge volute with tangential exit

While the impeller is rotating, the vanes give a centrifugal thrust tothe aspirated gas which is forced outwards into the toroidal discharge volute. The volute collects the gas delivering it to a tangential nosepiece. The compression occurs through the increment of kinetic energy given to the gas by the vanes of the impeller and the subsequent conversion of the kinetic energy into static pressure in the discharge volute.

Generalities and construction features in conformity with the 2014/34/EU Directive (ATEX)

The MAPRO® centrifugal fans, MCF Series to be used for extraction or compression of combustible gases, such as biological or natural gas, have been designed in order to fall within the Equipment- Group II as required by the 2014/34/EU Directive, Category 2 both for the surrounding area conditions and for the internals of the machines.

Main construction features:

• Aluminium casted casing, impeller made of spark proof aluminium alloy with caulked vanes, bearings housing made in cast iron and with aluminium casted caps, shaft in carbon steel
• Casing impregnated with Loctite;
• Casing halves sealed;
• Shaft sealing by a pair of special double-lip seals whose lubrication is provided by an automatic lubricator.

The centrifugal fans are generally coupled to the electric motor via belt drive and the safety drive guard is made of spark-free material.

We can also offer machines coupled to the electric motor via flexible shaft coupling and centrifugal fans manufactured in the so-called “CLOSE COUPLED” version (MCF..CC type) - i.e. a flange mounted electric motor is bolted to the fan casing and the impeller, which is dynamically balanced, is fitted directlyonto the motor shaft extension.

If the area surrounding the equipment is classified as Zone 1, the electric motors are flameproof, type of protection “d”, with specific marking Ex II 2 G, additional marking Ex-d IIB T3.
If the area surrounding the equipment is classified as Zone 2, where, for the Group II, Category 3 equipments are accepted, the machine could be equipped with the type of protection “n” non-sparking motor, with specific marking Ex II 3 G, additional marking Ex-nA II T3.

For particular duties and/or in function of the gas composition, fans with special construction features could be proposed; for example with the aluminium casted parts treated with anodic oxidation and the blades of the impeller in stainless steel; and it is also possible to fit the pair of double-lip seals on the shaft so that they are suitable for a barrier fluid in between.


Advantages

The rotating parts are not in contact with the casing during rotation. There is therefore no friction during operation and thus no internal lubrication is necessary.
The gas moving through the machine remains uncontaminated and completely oil-free.

The other main advantages of using the MAPRO® MCF centrifugal fans are:

• Easy installation
• Low noise level
• No vibration
• Pulsation free gas flow and no surge
• Minimal maintenance

The most common fields of application

The most common fields of application for MAPRO® centrifugal fans, MCF Series, are:

• Extraction of biogas from gasometer, natural gas from pipeline or gasometer, and burner or gas engine feeding
• Tank or plant gas recovery to feed torch or burner
• Biogas transfer from the production plant to remote satellite CHP units

The typical “flow rate - pressure” curve, rather flat at fixed rpm, and the absence of surging when decreasing the gas flow, make the MAPRO® centrifugalfans the ideal machines for all the applications in which the gas flow ratecould vary, even considerably. In fact, as the "flow rate - pressure"curve is quite flat on a large range of duty, the fan can immediately and safely react to the flow variations by moving its operating point along the curve itself.


Complete range of accessories:

• Gas-tight filters
• Stainless steel flanged flexible connection bellows
• Non return valves
• Pressure gauges and thermometers
• Explosion-proof pressure switches and temperature switches
• Intrinsically-safe pressure and temperature transducers
• Manual and automatic cut-off valves
• Acoustic enclosures

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