An Improved Method of and Means for Evaporating or Drying Viscous Substances, Semi-liquids, and Pasty Materials.
Year: 1897

page_text: An Improved Method of and Means for Evaporating or Drying
Viscous Substances, Semi-liquids, and Pasty Materials.
I, HUGH MCPHAIL, of The Towers, Wakefield, in the County of York, Engineer,.
do hereby declare the nature of this invention to be as follows:-
-
This invention relates to an improved method of and means for evaporating or
drying viscous substances, semi-liquids, and pasty materials by which the opera-
tions can be conducted very conveniently and expeditiously.
According to my invention the drying or evaporating agent employed is super-
heated steam in direct contact with the substances treated.
For the purposes of my invention I employ a drying or evaporating chamber
or vessel in which the substances to be treated are placed and I pass superheated
steam into, the said chamber or vessel and preferably draw the same off con-
tinuously through a suitable outlet by means of an exhaust pump or fan. The
superheated steam is brought in actual contact with the substances to be dried
or evaporated and preferably it passes through them and so acts very efficiently.
The slight amount of condensation of steam that takes place while the substances
are cold is soon re-evaporated along with the moisture originally contained by the sub-
stances when the temperature rises sufficiently high. The degree of superheat
is regulated as may be required according to the character of the substances and so as
to produce the desired result. When the boiler and superheater are a consider-
able distance from the drying or evaporating chamber or vessel it may be necessary
to further superheat the steam by a special superheater placed close to the drying
chamber or vessel. I sometimes superheat saturated or exhaust steam for the pur-
poses herein described. Any suitable form of superheater may be employed, and
the same may be heated by gas, oils, coal, coke or other suitable heating agent.
I sometimes dispense with the exhaust pump or fan for exhausting or drawing
the steam through or from the drying chamber or vessel, and in such cases I blow
the steam through or into the chamber or vessel. The steam may be caused to
take a circuitous path in its passage through the drying chamber, for instance it
may pass under and over trays containing the substances to be treated, but I prefer
as before stated to cause the steam to actually pass through the substances. I
may employ this method for concentrating or evaporating molasses, sugar, syrup,
glycerine, tar and pitchy materials, pulp, soap, acids, alkalies and the like and
for drying pasty materials generally. When it is necessary a reducing-valve
is used to reduce the pressure of the superheated steam.

page_text: An Improved Method of and Means for Evaporating or Drying
Viscous Substances, Semi-liquids, and Pasty Materials.
I, HUGH MCPHAIL, of The Towers, Wakefield, in the County of York, 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 follow-
ing statement:-
I have described in the Complete Specification of an Application for Patent
No. 11,448 of 1897, filed simultaneously herewith, a method of drying such
materials as yarns and textile fabrics by superheated steam brought into actual
or direct contact therewith. It is the object of my present invention to utilize
the same method for evaporating and drying substances of a viscous semi-liquid
or pasty character whereby these operations can be conducted very easily and
expeditiously.
The manner in which I carry out my invention is similar to that set forth in my
aforesaid specification, that is to say I employ a drying or evaporating chamber or
vessel in which the substances to be treated are placed and to which the super-
heated steam is supplied from a superheater which may be arranged in proximity
thereto, the superheated steam after taking up or absorbing the moisture from the
substances under treatment being withdrawn from the chamber or vessel by any
suitable means.
This method may be employed for concentrating or evaporating molasses, sugar,
syrup, glycerine, tar and pitchy materials, pulp, acids, alkalies and the like, and
for drying pasty materials generally.
In the accompanying drawings I have illustrated apparatus suitable for carry-
ing out my invention; Figure 1 being a vertical section and Figure 2 a plan
thereof.
A is the chamber or vessel within which the substance to be treated is placed.
B is a pipe, through which the superheated steam is led from the superheater into
tho said vessel A. This pipe is provided with a valve 131 and terminates within
the vessel A in a number of branch pipes B³, situated near the bottom of the
said vessel, each branch pipe having lateral perforations through which the super-
heated steam escapes into direct contact with the substance in the vessel A.
C is an opening at the bottom of the vessel A provided with means for closing it;
through this opening the substance within the vessel A can be allowed to flow away
after having been treated.
A number of the said vessels A may be arranged in a chamber that is capable
cf being tightly closed, such chamber being, if desired, provided with steam coils
o" a steam jacket in an analogous manner to that set forth in my aforesaid Specifica-
tion No. 11,448 of 1897.
This enclosing chamber may also if desired be provided with superheated steam
supply pipes, and when suction is employed for removing the superheated steam
from the said chamber I form one or more openings therein to enable an exhaust
pump or fan to be connected thereto.
I wish it to be understood that I do not confine myself to the apparatus herein
shown and described, as I may employ apparatus of other construction. For
instance apparatus of the kind illustrated in the drawings forming part of my
Application for Patent No. 11,449 of 1897 could be utilized for my present purpose.
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 T.
claim is:
1. A method of evaporating or drying substances of a viscous, semi-liquid or

page_text: pasty character by subjecting them to the direct action of superheated steam sub-
stantially as described.
2. Apparatus substantially such as that herein described, employed for the
purpose of my invention as above set forth.
Dated this 7th day of February 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.