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EKOFINN-POL Ltd
ul. Lesna 12
80-297 Banino - Poland

tel. +48 58 684 87 03
fax +48 58 684 99 98
e-mail: ekofinn@ekofinn.pl

ROBUSCHI® Roots Blowers   

The Roots blowers are a positive displacement machine with rotary double or triple toothed rotors, used for gas transportation. Gas is forced between rotors and machine body. The shaft with the first rotor drives a second rotor shaft through a toothed gear and the movements of both rotors are synchronized. During operation rotors don't meet each other and the machine body. The gas transportation is possible due to minimum slots against rotors and rotors and machine body.
 
 
 

Application

The Roots blowers are widely used if a relatively high capacity at inconsiderable compression ratio is required, such as:

  • aeration systems in industry sewage treatment plants and water conditioning systems
  • power industry: transport of ash
  • food industry: drying, vacuum packing
  • chemistry and pharmaceutical industry: removal of gas and vapours, vacuum furnances, transport and separation of granulated products
  • electronic industry: production of integrated circuits, gas circulation in lasers
  • pneumatic transport of bulk material installations
  • installations of ash cleaning
  • installations of gas recirculation, aeration of combustion or cooling processes

 

Structure

ROBOX is an integrated compression package for conveying low pressure gases, equipped with the RBS positive displacement rotary lobes blower, driven by an electric motor through a special V-belt transmission, and complete with all necessary accessories. ROBOX packages perform up to 150 m3/min capacity and fit up to 250 kW motors.
For higher capacities and up to 250 kW motor installed power, GRB packages with standard V belt drive transmission are available, whereas for installed power over 250 kW, CRB packages with direct drive or gearbox are used.

ROBOX consist of the following units:

  • Blower
    The heart of ROBOX is the innovative RBS blower, especially designed to suit this special compression unit.
  • Inlet silencer
    The inlet silencer consists of a patented, adjustable device that can be tuned in order to reduce the noise at blower's basic frequency through the interference phenomenon of sound waves, and of an absorptive device fading the noise frequecies over 500 Hz. The filter is positioned into the silencer, just before the blower inlet port, avoiding pollution of conveyed gas even in case the absorbing material is damaged. In GRB, CRB packages, the silencer is a broad frequency band resonance type without sound absorbing material.
  • Discharge silencer
    The discharge silencer consists of a cross flow resonance chamber cutting noise frequencies over 500 Hz, connected in series to a patented adjustable device reducing the noise at blower's basic frequency through the interference phenomenon of sound waves. The discharge silencer has been especially designed to reduce pressure losses in the conveyed gas flow.
  • The absence of deadening material prevents the gas pollution and guarantees steady, efficient operation of the silencer throughout the time. The silencer body is a part of the baseplate, common to the blower and to the driving motor.
    In GRB, CRB packages, silencer is a broad frequency band resonance type without sound absorbing material.
  • Drive
    The V-belt drive is designed with a special patented device, supporting the motor on swinging brackets, which reduces loads on blower''s and motor''s bearings, assuring and keeping automatically the correct belt tension during operation, with no need of periodical adjusting.
  • In GRB packages V-belt drive is adjusted through a standard slide rails tensioning device suitable for motors up to 250 kW. In CRB packages the drive is direct through a standard flexible coupling or through gearbox to suit motor power up to 500 kW.
  • Electric Motor
    ROBOX is designed for three phases, B3 type, IEC norm motors with minimum IP 55 protection.
  • Safety Valve
    The safety valve limits the operating differential pressure value of the blower. It is made of G200 galvanized cast iron to make it weather-proof.
  • Check valve
    The valve prevents counter rotation of the blower when it is stopped under load. It is provided with a new disc in heat resistent rubber, reinforced with metallic core, which grants free gas flow through its full open passage section, reducing pressure losses and avoiding disc clattering under low flow conditions.
  • Unloading valve
    The valve, available upon request, allows direct gas discharge during start up, in particular when using star-delta starters. Operation is fully automatic and does not require an electric actuator. Electric control can be provided upon request, in case of special running cycles.
  • Noise enclosure
    Noise enclosure allows to meet the most stringent noise specifications. It is provided with self supporting, galvanized steel panels coated with polyurethane self extinguishing sound absorbing material. Side panels shield the package down to ground level assuring the highest noise reduction effect. Two galvanized steel bars form the ROBOX supporting base and the enclosure lifting frame during ROBOX positioning on site.

 

Blower RBS

Is the new innovative positive displacement rotary blower especially designed for application in ROBOX packages. The Blower fits special profile three lobes rotors which, together with a new design of the LOW-PULSE system, reduce residual pulsations of the conveyed gas below 2% of the operating pressure. Oversized shafts allow higher working pressures and higher rotation speeds. Reinforced bearings and in particular the drive shaft one are positioned closer to the rotor in order to cope with high V-belt drive loads.

  • Bearings
    Roller bearings are used, selected for B10 life of at least 100.000 hours under the heaviest operating conditions.
  • Gears
    Helical teeth gears are used, with hardened and grounded surface assuring a running life close to those of the bearings. Gears are oil press driven on taper shafts.
  • Seals
    Sealing of the conveyed gas is assured by labyrinth seals on the shaft integrated with oil slinger. These seals ensure that the gas is conveyed oil free assuring proper operation for long life as they are without wearing parts. To convey special gas, blowers with special seals (/TM-V /PR-V) can be supplied. The drive shaft is sealed by a lip seal, but for special applications it is possible to install mechanical seals (/TMS).
  • Lubrication
    Bearings and gears are lubricated by the oil splashed through disks fitted on shafts.
  • Cooling
    The blower and the lubrication oil are cooled by natural convection up to the outlet gas temperature of 150 oC. Beyond this temperature please contact Robuschi (or any authorized distributor) for additional cooling.

 

 

 

Blower selection

For quick selection of the Blower size use the selection diagrams. Entering with Capacity and Differential Pressure data, charts give Blower type, motor size and noise level for units equipped with enclosure.
Charts are valid for pressure operation with standard, 1,2 kg/m3.
specific weight, atmospheric air. Noise levels on charts refers to Sound Pressure measured at 1 m from the unit, in free field conditions, in accordance with norm ISO 3746.
For precise calculation of running data or in case of gases different from standard air, or in case of operation different from the pressure one, always ask selection through ROBUSCHI''s Machines Selection Program available at ROBUSCHI''s Sales offices and Distributors.

 

Drive

  • Belt transmission
    The tip speed of the pulleys must be < 32 m/s.
  • The electric motor
    The electric motor selected in selection diagrams is valid for most of the applications. It may be necessary to use de-rated motors according to the starting frequency, the ambient temperature (if > oC), the altitude (if > 1000 m) or the requested protection (if > IP 55), for which we recommend to contact the electric motor manufacturer.
  • Starting system:
    Direct on line: recommended for motors up to 4 kW
    Star / delta: The blower cannot be started under different pressure, use the unloading valve VSM
    Electronic starters: The blowers can be started under load, apply to distributor / manufacturer.
  • Frequency inverters:
    Consult the motor and Frequency Inverter manufacturer specifying the following parameters:
    a) Motor torque Mmot = 9550 * Nblower / RPMmot (constant when speed varies).
    b) Electric Frequency Range (suggested between 20 Hz and 50 Hz)
    c ) Check the motor ventilation and its possible de-rating (suggested servo ventilated motor).