Batch Centrifugal Machine Capacity and Gravity Factor Calculation

Formulas for Batch Centrifugal Machine Capacity and Gravity Factor with Online Calculator

The batch centrifugal machines have been using to handle white and refined sugar massecuites as well as for affination of raw sugar in the sugar refineries. The batch machines were fully satisfying the sugar industry requirements for high sugar quality such as: low color, no lumps and low residual moisture content.

The purpose of this article is to evaluate the batch centrifugal machine capacity and its gravity factor

Parameters to be required for calculation:Batch Centrifugal machine capacity and gravity factor

Basket Shell Internal Diameter in meters = D

Thickness of the massecuite in meters   = e (Generally “e” value taken 0.14D for theoretical and 0.12D  for practical)

Basket top plate angle to horizontal level in Deg.= θ (Generally this value having 5deg.)

Height of the basket in meters= H

RPM of the basket (maximum RPM in Cycle)  = N

Time required for one cycle in sec    = T

Density of the massecuite in gm/ml    = S

Formulas for Calculation :

Volume of the massecuite per cycle in M3  (M3/cycle)  = V      = π e[ H(D-e) + e tanθ ((3D-4e)/6)]

No. of cycles per hour  (cycle/hr)                              =C       =3600/T

Capacity of the machine (Theoretically)                = Q      = C x V in M3/hr  (M3/cycle x Cycle/hr)

                                                                                                =Q x S in tons/hr

But in practically calculating the capacity of machine takes the following considerations.

  1. Take 1 to 2 empty cycles during in an hour (Depends on massecuite condition) so consider one empty full cycle in total cycles per hour.
  2. While charging the massecuite is always purged, spelling out some molasses such that creating space for further massecuite. This is called purging capacity. It is 10% more than theoretical capacity.

Capacity of the machine (Practically)  =Q       = [(C-1) x V] x 1.1 in M3/hr

= Q x S in tons/hr

Empty Basket Shell Radius in mtrs    = R   = D/2

Basket Shell Radius with massecuite in mtrs   = r    = R-e

Mean Equivalent Radius in mtrs = Rm = 2/3 [(R3 – r3) / (R2 – r2)]

Gravity factor     = G   = Rm x 1119 x (N / 1000)2

Gravity factor (General formula)   = G   = D x N2 / 1800

Explanation for gravity factor formula

Gravity Factor   =     Centrifugal force /  Gravitational force

=   m x  Rm x w2   / m x g.

Where Rm is M.E.R. and

  w = angular velocity   = 2 π N  /60      g = 9.8 m/sec2

Gravity Factor =[ Rm . X  1 X (2πN / 60 )2 ] / 9.8

   = Rm x 1119 x (N / 1000)2

Online Calculator to find Batch Centrifugal Machine Capacity and Gravity Factor

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Post Author: siva alluri

The aim of this Blog "sugarprocesstech" is Providing basic to advance knowledge in sugar process industry and providing maximum calculation regarding capacity and equipment design online calculators .

11 thoughts on “Batch Centrifugal Machine Capacity and Gravity Factor Calculation

    Awanish kumar

    (May 8, 2017 - 9:21 am)

    How you are converting that volume into kg/charge
    Volume of the massecuite per cycle in M3 = = π e[ H(D-e) + e tanθ ((3D-4e)/6)]

    No. of cycles per hour =C =3600/T

    Capacity of the machine (Theoretically) = Q = C x V in M3/hr
    =Q x S in tons/hr

    & Gravity factor = G = Rm x 1119 x (N / 1000)2

    Is not coming accordingly.

    Please suggest.

      siva alluri

      (May 9, 2017 - 2:05 pm)

      Thank you for your commenting sir
      Explanation for above given default example in calculator

      Practical capacity Theoretical capacity
      Tanθ 0.087 0.087
      H(D-e) 1.586 1.550
      (3D-4e)/6) 0.714 0.691
      e tanθ ((3D-4e)/6) 0.013 0.014
      π e[ H(D-e) + e tanθ ((3D-4e)/6)] 1.024 1.169 M3 /cycle
      V x Density x 1000 x1.1(10%extra for pratical capacity only)) 1644.443 1706.586 Kgs/Cycle
      Capacity of the machine x No. of cycles per hour 31244.42 34131.72 Kgs/hr
      31.24 34.13 Ton/hr
      R = D/2 0.850 0.850
      r = R-e 0.646 0.612
      Rm = 2/3 [(R3 – r3) / (R2 – r2)] 0.753 0.737
      Rm x 1119 x ( N / 1000)2 928.526 910.000


    (November 13, 2017 - 12:47 pm)



    (December 15, 2017 - 9:00 am)

    Hello sir,
    The calculations are very helpful.
    Do you have the data and calculations for continuous centrifugals and those for the drying section?

      siva alluri

      (December 15, 2017 - 4:02 pm)

      Thank you for your appreciation
      we published soon regarding this top


    (December 18, 2017 - 7:55 am)

    Hello Sir,
    your calculation is very helpful. Since i have study about the centrifugal for the sugar processing, i need to explain about the calculation in details. I have try using your calculation and i got the answer, but when i calculate manually, it is too different. Could you help me ?


    (February 9, 2018 - 7:52 am)

    very good ormula.

    B. N Amarendra

    (March 31, 2018 - 1:36 pm)

    sir, Pl tell me about massecuite reheater design calculation

    Shubham sadalage

    (July 7, 2018 - 9:05 am)


      siva alluri

      (July 12, 2018 - 1:43 pm)

      It is very simple
      1. Find the hole dia of the screen – i.e mesh size ex: 0.06 (60 micron) or 0.09 ( 90 micron)
      2. Find the no of holes per
      3. Find the perforated area of the each segment of the screen and calculate total area in
      Now we can find the screen opening area

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