Apparatus for continuous distillation

A compact integral apparatus is provided for the continuous distillation of water. The apparatus comprises an upright cylindrical boiling vessel communicating at an upper portion thereof with a vapor condensation tube which leads into a water cooling tube disposed within a reservoir vessel. Water is supplied to said reservoir vessel through a float-controlled valve adapted to maintain a substantially constant amount of water in said reservoir vessel at a height sufficient to immerse said water cooling tube and thereby receive heat therefrom. Water to be distilled flows by gravity from said reservoir vessel to said boiling vessel. The component parts are structurally interconnected to facilitate facile mounting of the apparatus on a support structure.

BACKGROUND OF THE INVENTION 
This invention relates to a distillation apparatus, and more particularly 
to improvements in an apparatus for the continuous automatic distillation 
of a volatile liquid such as water. 
The purification of liquids by distillation is well known, and various 
types of equipment find widespread utilization in distillation operations. 
The requisite features of distillation apparatus generally include a 
boiling vessel, condensation means to cause the vapors created in the 
boiling vessel to return to the liquid state, and a receiver vessel to 
capture and confine the liquified product produced by the condensation 
means. 
In distillation systems designed to handle a continuous feed stream of 
liquid to be purified, special control means are required to regulate the 
flow of liquid into the boiling vessel and to remove purified product from 
the receiver vessel and nondistillable residues from the boiling vessel. 
Such control means should be of simple and durable construction to enable 
the apparatus to function reliably for extended periods without 
maintenance. 
Water distillation units of relatively small capacity designed for home or 
industrial use are generally required to be of compact size and amenable 
to easy installation and operation. Such units should preferably be 
further equipped with control means which facilitate intermittent 
operation. To reduce the cost of operation, particularly the cost of 
heating the water to volatilization, the distillation apparatus should be 
designed in a manner which affords efficient use and recovery of thermal 
energy. 
Unlike complex fractionation systems capable of selectively condensing and 
isolating specific components of a volatile mixture, a distillation 
process merely separates volatile from non-volatile substances. If, for 
example, a water supply contains volatile impurities such as chlorine, 
chloramines and/or chlorinated organic species including chloroform known 
to be produced by chlorine, such species cannot be removed by ordinary 
distillation methods because they will co-distill and co-condense with the 
water. Although various techniques may be sequentially combined to purify 
water, practical single process means for the production of pure water 
from a feed stream containing volatile and nonvolatile impurities have not 
heretofore been available. 
It is accordingly an object of the present invention to provide a compact, 
easily installed apparatus for the distillation of water continuously 
supplied to said apparatus. 
It is another object of this invention to provide an apparatus of the 
aforementioned nature having the ability to remove from water substances 
more volatile than water. 
It is a still further object to provide an apparatus of the aforementioned 
nature wherein the component functional parts of said apparatus are 
designed and arranged in a manner to efficiently utilize the thermal 
energy required to achieve distillation. 
These and other objects and advantages of the invention will be apparent 
from the following description. 
SUMMARY OF THE INVENTION 
The above and other beneficial objects and advantages are accomplished in 
accordance with the present invention by the provision of an improved 
distillation apparatus which comprises an elongated vertically disposed 
cylindrical boiling vessel having an electrical heating element positioned 
adjacent the bottom thereof, a vented reservoir vessel which holds water 
awaiting distillation and sends said water by gravity flow through a 
transfer conduit to said boiling vessel, a float valve associated with 
said reservoir vessel which controls the admission of water from a water 
supply conduit in a manner to maintain a substantially constant water 
level in said reservoir vessel, a vapor condensation tube communicating at 
its entrance end with an upper portion of said boiling vessel, and 
communicating at its exit end with a water cooling tube disposed in a 
manner to be immersed in water confined within said reservoir vessel, and 
exit means for removing water from said water cooling tube, the various 
aforesaid components of said apparatus being interconnected in a manner 
causing said apparatus to have a structurally integral nature. 
The boiling vessel is preferably provided with mounting means adjacent its 
upper extremity to facilitate attachment of the apparatus to a support 
member such as a wall. The reservoir vessel, in preferred embodiments, is 
of open top construction, thereby providing the maximum possible venting 
to the atmosphere. 
The vapor condensation tube is preferably disposed directly above said 
reservoir vessel. Both the vapor condensation tube and the water cooling 
tube preferably have a spiral configuration. The exit means for removing 
water from said water cooling tube may be at an elevation lower than or 
equal to that end of said water cooling tube which joins with said vapor 
condensation tube.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, a distillation apparatus of the present invention is 
shown comprised of vertically upright boiling vessel 10 having positioned 
at the bottom 11 thereof electrical heating element 12. Valved drain means 
13 is positioned in vessel 10 adjacent the bottom 11 thereof and adapted 
to cause removal of liquid residue from said vessel. A mounting bracket 14 
engages vessel 10 adjacent the upper extremity thereof, said bracket being 
adapted to facilitate attachment of the distillation apparatus to a 
support structure. The upper extremity 15 of vessel 10 communicates with 
tube 16 adapted to achieve condensation of water vapor to produce water in 
the liquid state. Said tube 16 is of spiral configuration and provided 
with a multitude of cooling vanes 17 which function to increase the 
external heat transfer surface of tube 16. A pressure control valve 18 
communicating with tube 16, and associated guage 19 affords the ability to 
regulate pressure within the distillation apparatus. 
The lower extremity of downstream end of tube 16 merges in a continuous 
manner with the upper or upstream terminus of water cooling tube 20 having 
a spiral configuration. Said water cooling tube is positioned within 
cylindrical reservoir vessel 21 in a manner such that it will be immersed 
in water confined within said reservoir vessel. The lower or downstream 
terminus of water cooling tube 20 is provided with valve means 22 adapted 
to control the flow of water from said tube. 
A float valve mechanism 23 is located within reservoir vessel 21 and 
adapted to control the level of water contained within said vessel. The 
float valve mechanism is comprised of a float 24 attached to vertical 
extension rod 25 having a valve head 26 at the lowermost extremity which 
mates with a correspondingly shaped valve seat 27. A water inlet conduit 
28 provides a continuous supply of water to the aforesaid valve mechanism 
for controlled admission to reservoir vessel 21. 
A transfer conduit 29 containing check-valve 30 delivers water by gravity 
flow from the bottom of reservoir vessel 21 to the bottom of boiling 
vessel 10. A connecting strut 31 achieves rigid structural integration of 
boiling vessel 10 with reservoir vessel 21. 
In operation, water to be distilled is delivered by inlet conduit 28 to 
valve head 26 which controllably admits water into reservoir vessel 21. 
The water then flows through transfer conduit 29 to boiling vessel 10, 
thereby establishing equal levels of water in both vessels. The heating 
unit 12 causes volatilization of water. The water vapor (or steam) travels 
upwardly into vapor condensation tube 16, wherein cooling action is 
achieved by the passage of air, water or other coolant streams in contact 
with the outer periphery of said tube, causing the vapor to condense to 
liquid phase water. In the course of said cooling and condensing action, 
the heat earlier required to vaporize the water, namely 540 calories per 
gram of water, is given up to the cooling media, which is thereby raised 
to a higher temperature. If said cooling media is water, which is allowed 
to fall into reservoir vessel 21, the heat acquired by said water by 
virtue of contact with condensation tube 16 represents a saving of total 
energy required of heating element 12 to volatilize water in boiling 
vessel 10. If said cooling action is achieved by a flow of air as may be 
produced by a fan, the resultant stream of heated air may be directed so 
as to make efficient use of the heat. 
The water which condenses in condensation tube 16 flows downwardly through 
water cooling tube 20 wherein heat is transferred from said condensed 
water to water held by reservoir vessel 21 awaiting distillation. Such 
transfer of heat preheats water prior to its entrance into boiling vessel 
10, and represents a still further recovery of thermal energy. The heating 
of the water in the reservoir vessel also causes volatile substances 
dissolved in the water to leave the water through the air-water interface 
adjacent the top of the reservoir vessel, and thereby enter the ambient 
atmosphere. Such removal of volatile substances is enhanced by a large 
air-water interface and adequate venting to the atmosphere, as is obtained 
when the reservoir vessel is of an open top construction. 
The condensed water, following its passage through water cooling tube 20, 
may be drawn off for use in either a continuous or discontinuous manner. 
When discontinuous removal of said water is sought, sensor means of well 
known design may be utilized to detect the amount of water within cooling 
tube 20, and turn off heater element 12 to conserve energy. 
After prolonged periods of operation, non-distillable residues will 
accumulate in the water in boiling vessel 10. Removal of such material is 
achieved by periodic draining of water from boiling vessel 10 via drain 
means 13. 
Because the various components of the apparatus are rigidly interconnected, 
the apparatus is caused to have a compact, integral construction amenable 
to facile attachment to a support structure such as a wall of a building. 
While particular examples of the present invention have been shown and 
described, it is apparent that changes and modifications may be made 
therein without departing from the invention in its broadest aspects. The 
aim of the appended claims, therefore, is to cover all such changes and 
modifications as fall within the true spirit and scope of the invention.