Flexible Couplings ( RB ) - Coupling Manufacturer
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RB Design Variations |
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| The RB coupling eange can be adapted to meet customer needs,.Below are some of the arrangements that have been produced. For more comprehensive list contact-
POONA COUPLING PVT. LTD. |
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| Coupling with large boss driving flange and long boss inner member for vertical applications. |
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| Coupling with Brake drum for use on cranes fans and conveyor |
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| Cardon shaft coupling used to increase the misalignment capability and halve the torsional stiffness. |
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| Spacer coupling used to increse the distance between shaft ends and allow easy access to driven and driving machine. |
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Coupling Selection |
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To select a coupling for a given application the appropriate prme mover and driven equipment service factors must be applied. |
| COUPLING RATING = hp / rpm (Prime Mover Service Factor +Driven Equipment Service factor ) |
For example, the coupling rating for a centrifugal pump driven by a 6 cylinder desel engine rated at 1000 bhp at 900 rpm would be
1000 / 900 ( 1.7+1.25 ) + 3.28 hp / rpm |
| A coupling rating of 3.86 hp / rpm would therefore be chosen. |
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+ These applications require special consideration and transient response analysis. |
* The application of these drive type is highly specialised so please contact-POONA COUPLINGS for coupling selection. |
• Operation at speeds in excess of catalogue maximum could be approved in certain application. Such caseswould require dynamic balancing and should only be applied following approval from POONA COUPLINGS |
• For ease of assembly the coupling elements and cavity areas should be coated with silicon fluid. Insert the elementsin pairs, with the second pair diametrically oppoite the first the third and fourth pair at 90 etc. |
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| SELECTION EXAMPLE |
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| SELECTION EXAMPLE |
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* Selection of 6 Cylinder Diesel Engine 750 KWat 900 rpm driving centrifugal pump--
The coupling is flywheel ounted
Pump shaft diameter =dm
P =750 kW n =900 rpm
dm =95 mm temp =30 C
Fp =1.7 Fm =1.5
Tnorm = ( P / n ) X 9549 Nm
=( 750/900 ) X 9549
=7.958 kNm
Tmax =Tnorm (Fp+Fm )
=7.958 ( 1.7 + 1.5 )
=25.466 kNm
• The application is considered light industrial and RBtype coupling should be selected.
Examination of RB catalogue shows RB 3.86 as:
• Tkmax =27.4 kNm Tkn =9.159 kNm
Which satisfies the condition
• Tmax <Tkmax ( 25.466 < 27.4 ) kNm
• Tnorm < Tkn (7.859 < 9.159 ) kNm
• n< Coupling Maximum Speed ( 900 < 2500 ) rpm
• dmin < dm < dmax ( 80 < 95 < 170 ) |
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Our Parent Company ( Renold Hi- Tech ) is world leader in torsional vibration analysis for all types of machinery, using Computer programmes developed in house |
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We have also been offering this service mainly to indian Diesel Engine Industry through these programmes available with us. |
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| Product Range |
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RUBBER-
* Full laboratory control
* Supported bya wide range of sdpecialised equipment,
* Maintain high quality standards.
* Consistency in product performance. |
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DAMPING CHARACTERISTICS |
Coupling damping varies with torsional stiffness and inversely with frequency for a given rubber grade. This relationship is conventionally described by the dynamic magnifier. M. varying with hardness for the various rubber types.
This property may also be expressed as the Damping Energy Ratio or Relative Damping y. which is the ratio of the damping energy Ad. produced mechanically by the coupling during a vibration cycle and converted into heat energy, to the flexible strain energy. Af. with respect to the mean position.
Where C= Specific Damping ( Nms / rad )
K = Torsional Stiffness
W= Frequency ( Rad /s )
M= Dynamic Magnifier
d= Phase Angle Rad
y= Damping Energy Ratio
The rubber compound dynamic magnifier values are shown in the table below.
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