Improvements in Evaporating Pans.
Year: 1890

page_text: Date of Application, 28th Apr., 1890
Complete Specification Left, 16th Jan., 1891-Accepted, 7th Mar., 1891
PROVISIONAL SPECIFICATION.
Improvements in Evaporating Pans.
I, GEORGE FLETCHER, of Masson Works, Litchurch, in the County of
Derby, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to pans for the evaporation by boiling of cane juice and
other liquids, the said invention being applicable either to open pans working
under atmospheric pressure, or to closed vessels working under more or less
complete vacuum and has for its object to promote the circulation of the boiling
liquids.
In a pan or vessel constructed according to my invention the heating surface is
preferably formed by tubes fixed in tube plates which latter are also fixed to the
sides of the pan or vessel; or by means of a drum containing the bulk of the
heating surface, also in the form of tubes, the said drum being fixed in the pan or
vessel.
In the above mentioned pan or vessel I place a circulating tube or tubes of such
dimensions that the area, or the combined areas if more than one is used, is equal
to the combined areas of the heating tubes; and in the case of the drum placed in
the pan I make the combined area of the circulating tube or tubes and of the
annular space round the drum and between it and the sides of the vessel or pan
equal to the combined area of the heating tubes. Instead of inserting a large
circulating tube or tubes in the pan, vessel or drum I can fix internal tubes in the
heating tubes, the combined areas of these internal tubes being equal to the
combined areas of the annular spaces surrounding them in the heating tubes.
The object of the invention is to promote the circulation of the boiling liquids
in the pan or vessel. By making the circulating tube of large area I obtain a free
circulation of the liquor. This perfect circulation greatly increases the value of
the heating surface in the pan or vessel and thus enables a larger amount of work
to be accomplished in a given time with a certain amount of heating surface. Also
the rapid circulation of the liquor allows the steam or vapour generated to disengage
itself with rapidity and freedom from the liquor and thus enables it to boil fiercely
at a somewhat lower temperature and at the same time tends to decrease the
tendency to blowing up or boiling over, that is so prevalent and troublesome in
vessels or pans used for evaporating purposes.
Dated the 28th day of April 1890.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Evaporating Pans.
I, GEORGE FLETCHER, of Masson Works, Litchurch, in the County of Derby,
Engineer, do hereby declare the nature of this invention, and in what manner
the same is to be performed, to be particularly described and ascertained in and
by the following statement :-
My invention relates to pans for the evaporation by boiling of cane juice and
other liquids, the said invention being applicable either to open pans working
under atmospheric pressure, or to closed vessels working under more or less
complete vacuum and has for its object to promote the circulation of the boiling
liquids.

page_text: In a pan or vessel constructed according to my invention the heating surface is
preferably formed by tubes fixed in tube plates which latter are also fixed to the
sides of the pan or vessel; or by means of a drum containing the bulk of the
heating surface, also in the form of tubes, the said drum being. fixed in the pan or
vessel.
In the above mentioned pan or vesselt I place a circulating, tube or tubes of such
dimensions that the area, or the combined areas if more than one is used, is equal
to the combined areas of the heating tubes; and in the case of the drun placed
in the pan I make the combined area of the circulating tube or tubes and of the
annular space round the drum and between it and the sides of the vessel or pan
equal to the combined area of the heating tubes. Instead of inserting a large
circulating tube or tubes in the pan, vessel or drum I can fix internal tubes in the
heating tubes, the combined areas of these internal tubes being equal to the
combined areas of the annular spaces surrounding them in the heating tubes.
In order to enable my invention to be fully understood I will describe how it can
be carried into practice by reference to the accompanying drawings, in which
Figures 1, 3 and 5 are vertical sections of evaporating pans constructed
according to my invention, in which relatively large circulating tubes and small
heating tubes are employed.
Figures 2, 4 and 6 are plans of Figures 1, 3 and 5 respectively.
Figure 7 is a vertical section drawn to an enlarged scale of part of the tube
plates fitted with heating tubes having internal circulating tubes.
Figure 8 is a plan of the tubes.
Referring to Figures 1 and 2, A is the circulating tube and B, B: the heating
tubes fixed in the tube plates C, C secured to the sides of the pan or vessel E, the
area of the circulating tube A being equal to the combined areas of the heating
tubes B; B.
By this means, the requisite quantity of liquid to be treated being placed in the
pan or vessel E, and steam being admitted to the space between the tube plates B; B
and around the circulating tube A, a circulation of the liquid in the pan or vessel E
will be promoted, the course of the liquid being up the tubes B, B. and down the
tube C as indicated by the arrows in Figure 1.
This free or perfect circulation, obtained by making the circulating tube A. of
large area greatly increases the value of the heating surface in the pan or vessel E
and thus enables a larger amount of work to be accomplished in a given time with
a certain amount of heating surface. Also the rapid circulation of the liquor
allows the steam or vapour.generated to disengage itself with rapidity and freedom
from the liquor and thus enables it to boil fiercely at a somewhat lower temperature
and at the same time tends to decrease the tendency to blowing up or boiling over,
that is so prevalent and troublesome in vessels or pans used for evaporating
purposes.
The pan or vessel illustrated in Figures 3 and 4 is fitted with tubes similarly to
Figures 1 and 2 except that four circulating, tubes A, A, A, A are employed
instead of a single one the circulation taking place in a similar manner to that just
described.
In Figures 5 and 6 the pan or vessel is provided with tubes A and B, B placed
similarly to those shewn in Figures 1 and 2, but they are here shewn fitted in a
drum F connected to nozzles D, D, Figure 5, which serve to support it in the pan
or vessel E. In this case the combined areas of the heating tubes B,, B' are equal
to the combined areas of the circulating, tube A. and annular space H around the
drum F. The steam is admitted to the interior of the drum F through one of the
nozzles D and promotes a circulation of the liquid in the pan or vessel E as
herein before described, the water of condensation being discharged' through the
other nozzle D.
In Figures 7 and 8, the circulating tubes marked G G; are suspended inside the
heating tubes B, B, the area of each internal tube G being equal to the area
comprised by the annular space I between it and the heating tube B.

page_text: In this case the steam being admitted to the space between the tube plates CC
Figure 7, the circulation of the liquid to be treated takes place up the outer tubes B, B
and down the internal tubes G, G as indicated by the arrows in Figure 7.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what
I claim is :-
1. Open pans working under atmospheric pressure or closed vessels working
under more or less complete vacuum for the evaporation by boiling of cane juice
and other liquids, in which the heating surface is formed by tubes fixed in tube
plates, secured to the sides of the pan or vessel and fitted with one or more large
circulating tubes the combined areas of which are equal to the combined areas of
the heating tubes, substantially as hereinbefore described and illustrated in Figures 1
to 4 of the accompanying drawings.
2. An evaporating pan or vessel of the kinds herein referred to having a steam
drum containing the bulk of the heating surface formed also of tubes the said
drum being also fitted with one or more large circulating tubes the combined areas
of the heating tubes being equal to the combined areas of the circulating tubes
together with the area of the annular space surrounding the drum, substantially as
hereinbefore described and illustrated in Figures 5 and 6 of the accompanying
drawings.
3. An evaporating pan or vessel of the kind herein referred to having its heating
surface formed by tubes in which are fitted other tubes for promoting circulation
the area of each internal tube being equal to that of the annular space surrounding
it substantially as hereinbefore described and illustrated in Figures 6 and 7 of the
accompanying drawings.
4. The improved evaporating pans or vessels hereinbefore described and
illustrated in the accompanying drawings.
Dated the 16th day of January 1891
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.