The Sugar Engineers

Batch Vacuum Pan Design Specification

Please contact us if you require expert help in designing and specifying a pan for your factory

Refinery White Pan

Strike Level above tube plate	1300 - 1400 mm
Graining Volume % Strike Volume	less than 40 %
Graining Level above tube plate	50 mm
Heating Surface to Volume ratio	7.0 m^-1
Down Take Diameter % Pan Diameter	40 %
Disengagement space above strike level	2 m

Raw A (and First Crop Recovery) Pan

Strike Level above tube plate	1300 - 1400 mm
Graining Volume % Strike Volume	less than 35 %
Graining Level above tube plate	50 mm
Heating Surface to Volume ratio	6.0 m^-1
Down Take Diameter % Pan Diameter	40 %
Disengagement space above strike level	2 m

Raw B and C (and Second and Third Crop Recovery) Pans

Strike Level above tube plate	1300 - 1400 mm
Graining Volume % Strike Volume	less than 35 %
Graining Level above tube plate	50 mm
Heating Surface to Volume ratio	5.5 m^-1
Down Take Diameter % Pan Diameter	40 %
Disengagement space above strike level	2 m

Load Conditions

The following load cases shall be considered

Self weight
Weight of massecuite (pan filled to the very top)
Full vacuum in pan body
Full vacuum in calandria
Full design steam pressure in calandria
Calandria full of water
Full calandria pressure in the pan body

The following combinations of the above load cases shall be considered

a+b
a+b+c
a+b+c+d
a+b+c+e
a+b+c+f
a+b+c+d+f
a+b+e+g
a+c
a+c+d
a+c+e
a+c+f
a+c+d+f

The value of density used for massecuite shall not be less than 1500kg/m³.

Tube Plates

The tube to tube plate joint shall be by expansion. The expansion joints shall comply with the following requirements

Expansion shall be to TEMA C recommendations
Tube hole surface finish shall be in the range 1.6mm < R_a <= 3.2mm, assessed in accordance with BS1134
The tube hole nominal size shall be 102.28mm
The tube hole tolerance shall be H12
The tube plate ligaments shall be as follows
96% of all ligaments shall be greater than or equal to 16.94mm
100% of all ligaments shall be greater than or equal to 9.2mm

Tube specification

The tubes shall comply the sugartech specification for tubes less than three metres in length. Furthermore, the tubes shall be supplied in the annealed condition. The finished tube shall not have a weld bead either on the outside or the inside. The tube nominal diameter shall be 4 inches (101.6 mm), the tube wall thickness shall be 1.5mm.

Sight and Light Glasses

The sight glasses shall be arranged vertically with the centre of the second sight glass from the top at the design strike level. One light glass with and electric light fitting shall be located at the rear of the pan. Wash water sprays shall be provided to all light and sight glasses. The transparent material shall be Lexan or similar product, sufficiently strong to resist all load conditions.

Man-ways

Man-ways shall be of sufficient size so that the stirrer blades and the entrainment packs can be fitted and removed. No man-way shall be less than 450 mm in diameter.

Feed Manifold

The distribution of liquor to the pan shall be by means of an external ring line from which risers lead to radial distributors. The feed velocity shall not exceed 1 m/s 5.16 Calibrated level board A calibrated level board marked in metres and centimetres shall be provided adjacent to the sight glasses. The level board shall indicate height above the top of the top tube plate.

Pan Stirrer

The pan stirrer shall comply with the sugartech specification