Distilling apparatus

Distilling equipment comprising input apparatus (21) including a boiling chamber (83) and means (80-82, 104-107, 110, 111) for supplying raw liquid to the boiling chamber at a predetermined level, a closed condensation chamber (22) above the predetermined level and connected to the top of the boiling chamber (96) to receive therefrom only vapor from the raw liquid, and output apparatus (20) including a liquid collection container (25) below the condensation chamber and liquid circulating structure (29-34, 44-55) for withdrawing liquid from the container, cooling the liquid, discharging it within the condensation chamber, and returning it to the container.

TECHNICAL FIELD 
This invention relates to the field of chemical engineering, and 
particularly for intermediate-scale distilling applications such as 
deriving potable water from a source which because of non-volatile 
pollutants is saline or otherwise not potable, or for deriving alcohol of 
tractor-fuel grade as a byproduct of agricultural operations. 
BACKGROUND OF THE INVENTION 
Distillation, and fractional distillation, are well-known processes in 
chemical engineering. Apparatus and procedures for this use are known in 
laboratory type embodiments and in large scale commercial installations. 
There are, however, applications where these chemical procedures would be 
advantageous if intermediate-scale apparatus were available for reliable, 
trouble-free use requiring minimum supervision. One such application is 
the provision of potable water for individual farms and ranches in areas 
of the country where the natural water contains enough dissolved minerals 
to be unpleasant or physiologically unacceptable for drinking. Another 
application is the derivation, from suitable agricultural refuse at 
individual farms, of alcohol of purity adequate for use as a fuel for 
tractors and other engines. 
In these applications it is desirable to have the distillation equipment of 
limited dimensions so that it can be installed in small buildings. 
Equipment having tall towers is not feasible for installations of this 
sort: the well-known "barometric height" to which water, or 
water-and-alcohol, rises under a substantial vacuum, makes apparatus using 
such principles undesirable. 
SUMMARY OF THE INVENTION 
A system embodying the present invention comprises treated liquid output 
apparatus and raw liquid input apparatus, interconnected at a condensation 
chamber. The output apparatus comprises a generally vertical treated 
liquid supply column and a generally vertical treated liquid return 
column, interconnected near their tops for liquid flow through a portion 
of the condensation chamber, and the inlet apparatus comprises a generally 
vertical raw liquid boiling chamber having an upward extension connected 
to the condensation chamber near its top, to provide a path for material 
in vapor form only from the boiling chamber to the condensation chamber, 
without enabling movement therebetween of liquid material. The input 
apparatus draws raw liquid from a suitable source, heating it as 
necessary, and later discharges it at a lower temperature and a higher 
pollution concentration. The output apparatus recirculates treated liquid 
from a collection container, cools it as necessary to maintain its 
temperature at a lower level than that of the raw liquid, and later 
returns it to the container. Externally energized pumps are provided for 
maintaining operation of the system. 
Several modifications of the invention are shown. 
Various advantages and features of novelty which characterize the invention 
are pointed out with particularity in the claims annexed hereto and 
forming a part hereof. However, for a better understanding of the 
invention, its advantages, and objects attained by its use, reference 
should be had to the drawing which forms a further part hereof, and to the 
accompanying descriptive matter, in which there are illustrated and 
described certain preferred embodiments of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Turning first to FIG. 1, a water distillation system 19 according to the 
invention is shown to comprise output apparatus 20 and input apparatus 21 
having in common a condensation chamber 22. The system operates to take 
raw water from a source 23 open to the atmosphere, such as a pond or well, 
and to deliver treated water to a collection container 25 also open to the 
atmosphere, and having an overflow 26 from which the liquid output of the 
system is taken. 
Output apparatus 20 comprises means for circulating treated water at 
subambient temperature to cool the condensation chamber, and includes a 
treated water supply column 27 and a treated water return column 28. The 
columns are both generally vertical, and may, for example, be six feet in 
height. 
Return column 28 comprises in sequence a conduit 29, a heat exchanger 30, a 
conduit 31, a control arrangement 32, a conduit 33, and a distributor 34 
in chamber 22. 
Control arrangement 32 includes a throttling valve 35 actuated through a 
mechanical connection 36 by a low-speed reversing A.C. motor 37 actuated 
through a cable 38 by a controller 39: valve 35 is bypassed by a loop 40 
including a manual throttling valve 41 and a normally closed solenoid 
valve 42 actuated through a cable 43 by controller 39. It is understood 
that heat exchanger 30 is externally provided with cooling fluid, as 
suggested by arrows 44. 
Supply column 27 extends from container 25 through a conduit 45, a positive 
displacement pump 46 driven uniformly through a mechanical connection 47 
by a motor 48, and an inlet conduit 49 having an inlet port in a closed 
chamber 50, to a plurality of separate conduits 51 projecting below and 
sealed into the top of chamber 50, and sealed into and flush with the 
bottom of condensation chamber 22. The surface of the liquid in container 
25 is to lie above the lower ends of conduits 29 and 45. The surface of 
the liquid in chamber 50 is to lie above the lower ends of conduits 51, so 
that the inlet port of inlet conduit 49 is higher in chamber 50 than the 
lower ends of conduits 51. 
Distributor 34 comprises a plurality of nozzles 52 directed downwardly and 
toward the walls of the lower portion of chamber 22. 
A liquid level sensor 53 is connected by conduits 54 and 55 to the top of 
chamber 22 and the bottom of chamber 50, respectively, and is connected by 
a cable 56 to controller 39, as is best shown in FIG. 2. Here sensor 53 is 
shown to comprise a float 57 and a pair of vertically spaced movable 
contacts 60 and 61 which are normally out of engagement with a pair of 
fixed contacts 62 and 63, respectively. When the liquid rises above a 
first level, float 57 moves contact 60 into engagement with contact 62, 
and when the liquid falls below a second level float 57 moves contact 61 
into engagement with contact 63. Motor 37 is shown to comprise a pair of 
windings 64 and 65, a capacitor 66, and a rotor 67. Control of valve 42, 
and reversible control of motor 37, from an A.C. source 68, are exercised 
by sensor 53, in part through a relay 70 comprising a winding 71 which 
actuates an armature 72 to close a pair of normally open contact sets 73 
and 74. 
A normally closed tap 75 and a shut-off valve 76 in conduit 29 may be 
provided for priming the output apparatus with potable water. 
Returning to FIG. 1, input apparatus 21 includes a conduit 80 extending 
below the surface of the liquid in source 23, a normally closed solenoid 
valve 81, and a conduit 82 opening into a boiling chamber 83 having 
laterally displaced vertical branches 84 and 85. Branch 84 includes a heat 
exchanger 86 connected by conduits 87 and 90, sealed into the bottom of 
the chamber, to a solar heating panel 91: a pump 92 driven through a 
mechanical connection 93 by a motor 94 is included in conduit 90. Chamber 
83 has an upward extension 95, above branch 85, which has a connection 96 
to the upper part of condensation chamber 22, and which may contain 
refluxing material such as glass beads or metal mesh. 
At the bottom of boiling chamber 83 there is a drain connection 97 
including a conduit 98, a check valve 99 opening away from chamber 83, and 
a pump 100 driven through a mechanical connection 101 by a motor 102 to 
discharge liquid at 103. 
A second liquid level sensor 104 is connected by conduits 105 and 106 with 
the top of condensation chamber 22 and the bottom of boiling chamber 83 
respectively, and actuates valve 81 through a suitable cable 107, 
controller 110, and cable 111 as described for valve 42. 
Turning now to FIG. 3, a first modified control arrangement 112 is shown to 
comprise a manual throttling valve 113 bypassed by loop 40 including 
throttling valve 41 and normally open solenoid valve 42' controlled 
through cable 43 by a controller 39, which is in turn controlled through 
cable 56 by level sensor 53. In this modification valve 113 is not motor 
driven. 
A further modified system is shown in FIG. 4 to include a control 
arrangement 112 as just described. A controller 120 is energized by sensor 
53 through cable 56 to energize valve 42' through cable 43, as before, and 
is also connected by a cable 121 to control the operation of a D.C. motor 
119, so that the speed of pump 46 varies with the level sensed by sensor 
53. 
As shown in FIG. 5, contacts 61 and 63 of sensor 53 are not used in this 
arrangement. Controller 120 comprises a relay 122, having a winding 123 
which actuates an armature 124 to close a pair of normally open contact 
sets 125 and 126, and a pair of resistors 127 and 130. The controller is 
energized from A.C. source 68, and from a D.C. source 131. 
FIG. 8 illustrates another modification of the system which affects output 
apparatus 20. Return column 28 can further comprise a plenum 195 which has 
portions of conduits 51 passing therethrough. Plenum 195 is disposed 
sequentially intermediate heat exchanger 30 and conduit 31. 
A still further modification of the system is shown in FIG. 6. Here a 
source of liquid, which may be a fermentation mash--a mixture of ethyl 
alcohol, water, sugar solution, yeasts, and other carbohydrates--is shown 
at 132. This liquid is understood to be warmed, by the sun or some other 
source of heat, to maintain a proper temperature for fermentation. The 
fluid from source 132 is conducted to branch 133 of boiling chamber 134 by 
a conduit 135, which may include an input strainer 136, a motor driven 
throttling valve 137, and a conduit 140 which is sealed into branch 133 at 
an angle, to direct liquid emerging therefrom obliquely against the wall 
of the chamber. Level sensor 104 is connected by a cable 107 to a 
controller 141 like controller 39 in FIG. 1, which acts through a cable 
142 to control a motor 143 to actuate valve 137 through a mechanical 
connection 144 as described in connection with valve 35 of FIG. 1. Pump 
102 discharges into source 132. 
FIG. 7 shows how the thermal efficiency of the system shown in FIGS. 1 and 
6 may be improved. Here a heat exchanger 146 is submerged in the mash in 
source 132, to act as the condenser of a heat pump 147 having a compressor 
150 connected to heat exchanger 146 by a conduit 151 and to heat exchanger 
30, which comprises the evaporator of the heat pump, by a conduit 152, the 
path for refrigerant being completed by conduit 153 and an expansion valve 
154. This improves the thermal efficiency of the system by providing heat 
for warming the mash or raw water. 
OPERATION 
The operation of the system is as follows, referring first to FIGS. 1 and 
2. Motor 48 is driving pump 46 to create a negative pressure in conduit 
49, which is transmitted through chamber 50 and conduits 51 to 
condensation chamber 22. Atmospheric pressure acts on the liquid in 
container 25 to force treated water upward through heat exchanger 30, 
where it is cooled, and through control arrangement 32 to nozzles 52, the 
rate of flow being determined by arrangement 32 under the control of level 
sensor 53. Atmospheric pressure on the liquid in source 23 is also 
available to force raw water upward into boiling chamber 83 whenever valve 
81 is open. 
Pump 92 is running to circulate heat exchange liquid through solar heating 
panel 91 and heat exchanger 86, so that the temperature of the raw liquid 
in chamber 83 is superambient, while that from nozzle 52 is subambient. 
A pumping action takes place in supply column 27, to augment operation of 
pump 46, as will now be described. Liquid is supplied through nozzles 52 
to chamber 22 at such a rate that its entrance into conduits 51 is 
turbulent, and the flow down the conduit comprises mixed streams of liquid 
masses interspersed with gaseous bubbles carried downwardly with the 
liquid by gravity and by pump 46. It is important to note that a 
considerable number of conduits of small diameter are used here, rather 
than a single large conduit, to ensure adequate extraction from chamber 22 
of bubbles which are principally of water vapor, but may also include any 
air initially in the system or brought into the system dissolved in the 
raw water. After a short period of initial operation, the pressure in 
chamber 22 is substantially the partial pressure of water at a subambient 
temperature, the pressure in extension 95 is that of the partial pressure 
of water at the superambient temperature, which is greater, and water 
vapor moves from extension 95 to chamber 22, to condense on the cooler 
walls and the cooler water therein, and pass downward through conduits 51, 
chamber 50, and pump 46 into container 25. Here any component such as air 
which has not condensed is free to bubble to the surface. 
It is clear that the pressure in chamber 22 is essentially the vapor 
pressure of water at the subambient temperature. If that low pressure were 
also present at pump 46, the natural liquid seal of the pump would be 
destroyed by boiling of the liquid. This is prevented by the construction 
of supply column 27, which presents a pressure head equal to the height of 
a column of water of the length of conduits 51 less the total length of 
the bubbles in the conduits. The conduit length is chosen to provide a 
head of several feet, sufficient to prevent boiling of the liquid in the 
pump, and satisfactory sealing is accomplished. 
The operation of arrangement 32 to regulate liquid flow at nozzle 52 will 
now be explained. Sensor 53 is positioned at a level slightly below the 
bottom of chamber 22, since it has been found that in the length of this 
column approximately one foot is occupied by vapor bubbles rather than 
liquid. The main liquid flow through arrangement 32 is through throttle 
valve 35, with a subordinate flow through throttle valve 41 when solenoid 
valve 42 is open. 
If the liquid level at sensor 53 becomes too high, float 57 in sensor 53 
rises, closing contacts 60 and 62 to complete a circuit which may be 
traced in FIG. 2 from source 68 through conductors 160 and 161, contacts 
62 and 60, and conductor 162 to motor winding 64 directly, and to motor 
winding 65 through capacitor 66, the circuit being completed through 
conductors 163 and 164, 165, and 166. At this time valve 42 is not 
energized. Motor 37 operates slowly in a direction to close valve 35, thus 
reducing the rate at which liquid can flow to distributor 34. Continued 
operation of pump 46 causes the level of liquid to decrease, and sensor 
float 57 disengages contact 60 from contact 62 to interrupt motor 
operation, so that liquid flow continues at the slightly lesser rate 
resulting from the new position of valve 35. 
If the liquid level at sensor 53 becomes too low, float 57 descends, 
closing contacts 61 and 63 to complete a circuit which may be traced from 
source 68 through conductors 160, 167, and 170, contacts 61 and 63, and 
conductor 171 to relay winding 71, the circuit being completed through 
conductors 172 and 166. Relay 70 operates to complete a first circuit, 
form conductor 167 through conductor 173, contact set 74, and conductor 
174 to valve 42, the circuit being completed through conductors 175, 172, 
and 166 so that valve 42 is opened. Relay 70 also completes a second 
circuit, from conductor 177 to motor winding 65 directly and to motor 
winding 64 through capacitor 66, the circuits being completed through 
conductors 163 and 164, 165, and 166. Motor 37 operates slowly in a 
direction to open valve 35, and open valve 42 also passes fluid at a rate 
determined by the setting of manual throttle valve 41. The increased flow 
of liquid causes the liquid level to rise, and sensor float 57 disengages 
contact 61 from contact 63 to interrupt motor operation and enable closure 
of valve 42, so that liquid flow continues at the slightly greater rate 
resulting from the new position of valve 35. 
Proper manual setting of throttle valve 41 can result in quite stable 
system operation in which valve 35 reaches a setting which is very close 
to that providing exactly the correct liquid flow, and operations of 
controller 39 are infrequent and short. 
In FIG. 2, conductors 161, 162, 170 and 171 comprise cable 56 of FIG. 1, 
conductors 162, 165, and 177 comprise cable 38, and conductors 174 and 175 
comprise cable 43. 
Since the water vapor from extension 95 is continuously condensing by 
contact with the cooler walls of chamber 22 and the cool water from 
nozzles 52, a continuous flow of water in vapor phase passes out of 
boiling chamber 83. The level of water in this chamber is maintained by 
sensor 104, which energizes valve 81 to open and close as the liquid 
reaches lower and upper levels. 
Valve 81 is normally closed. if the liquid at sensor 104 drops to a 
predetermined level, the sensor float operates to open valve 81 as 
described in connection with valve 42, enabling the reduced pressure above 
boiling chamber 83 to draw liquid from source 23 into the chamber. When 
the liquid regains a desired level sensor 104 de-energizes valve 81, which 
closes to prevent further input of water into boiling chamber 83. 
Because of the continuous evaporation, the pollution content in boiling 
chamber 83 continuously rises, which also raises the boiling point of the 
liquid. To maintain stable system operation, pump 100 is operated from 
time to time to draw some liquid from the bottom of chamber 83 and 
discharge it to a waste, replacement of water being caused by sensor 104 
as the level descends. Pump 100 and check valve 99 are necessary because 
operation of pump 46 would prevent outflow of liquid through conduit 98, 
and might even draw waste in through conduit 103 and the pump. 
If desired, operation of pump 100 may be automated by providing a 
conductivity sensor in chamber 83 to energize and de-energize motor 102. 
The operation of the modification of the invention shown in FIG. 3 will now 
be apparent, as it is simply a less complicated arrangement which omits 
the motor control of one throttle valve. In this arrangement throttle 
valve 113 is manually set to provide slightly less than the necessary 
flow, and manual valve 41 is set to augment the flow, when valve 42 is 
open, by slightly more than the amount required for exact system 
operation. Level control is now accomplished by automatic opening or 
closing of valve 42. This gives a system which is continuously hunting, 
and is thus in this respect less perfect than that of FIG. 1. It is less 
costly to install and maintain, however, and is usable where initial 
system cost is a serious practical consideration. 
The embodiment of the invention shown in FIG. 4 operates in generally the 
same fashion, except for control of liquid flow in the output apparatus. 
Resistors 127 and 130 of FIG. 5 are so chosen that normally motor 119 is 
energized through a circuit which may be traced from D.C. source 131 
through conductor 180, resistor 127, junction point 181, resistor 130, 
conductor 182, motor 119, and conductor 183 to source 131, and the motor 
operates to drive pump 46 at a predetermined low speed. Valves 41 and 113 
are set so that slightly more than enough liquid is passed at this pump 
speed to maintain the level. As the level rises, float 57 causes contact 
60 to engage contact 62, and a circuit is completed from source 68 through 
conductor 184, contacts 62 and 60, and conductor 185 to relay winding 123, 
the circuit being completed through conductor 186. Relay 122 operates, 
completing a circuit from conductor 185 through conductor 187, contact set 
126, and conductor 190 to valve 42, the circuit being completed through 
conductors 191 and 186, and valve 42 closes to reduce the flow of 
additional liquid determined by valve 41. At the same time, relay 122 
closes contact set 125 to short-circuit resistor 127 through conductors 
192 and 193, increasing the speed at which motor 119 drives pump 46 to 
further increase the liquid flow and lower the liquid level to a point 
where fall of float 57 enables contact 60 to disengage contact 62, relay 
122 is de-energized, valve 42 opens, and motor 48 reverts to its lower 
speed. 
The modification of return column 28 as illustrated in FIG. 8 can be used 
with any embodiment heretofore described. The liquid in container 25 will 
be forced upwardly through heat exchanger 30 and into plenum 195 prior to 
entering conduit 31 and control arrangement 32. Since the treated liquid 
is passed through heat exchanger 30 prior to its entering plenum 195, its 
temperature will be lower than the temperature of the condensed liquid 
passing downwardly through conduits 51 and into chamber 50. Consequently, 
a heat exchange process will occur in plenum 195 wherein the temperature 
of the condensed vapor passing down conduits 51 will be reduced. 
The significance of the decreased temperature of the condensed vapor is 
that the distillate entering pump 46 is colder than it would otherwise be. 
The fluid entering pump 46 should be as cold as possible in order to 
inhibit any boiling action in the pump which might be induced by the 
vacuums in condensation chamber 22 and chamber 50. Such boiling action 
could have the adverse effect of destroying the seal in the pump and 
causing loss of lubrication. 
The embodiment of the invention shown in FIG. 6 is adapted for use where 
the raw liquid to be treated is already at a superambient temperature, so 
that additional heat from a heat exchanger is not needed. It also shows a 
modification of the boiling chamber designed to introduce raw water in 
such a way as to create a whirling vortex in one branch of the chamber; 
such an arrangement is very effective in suppressing the spray which 
otherwise might occur and be carried or projected up into the chamber 
extension 95, with danger of contaminating the apparatus. 
In FIG. 6 the pressure in chamber 134 is lowered as described in connection 
with FIG. 1, drawing raw liquid upward from source 132 through valve 137. 
If the liquid affecting sensor 104 rises to a first level, controller 141 
acts as described above to energize motor 143 in a sense to close valve 
137, reducing the flow from source 132 so that the level at sensor 104 
drops and motor 143 is de-energized in a slightly different position of 
valve 137. On the other hand, if the liquid affecting sensor 104 falls to 
a second level, controller 141 acts as described above to energize motor 
143 in the sense to open valve 137, increasing the flow from source 132 so 
that the level at sensor 104 rises and motor 143 is again de-energized. 
FIG. 7 shows portions of FIGS. 1 and 6 interconnected by heat pump 147, and 
those portions operated as previously described. The heat pump operation 
is as follows: operation of compressor 105 draws gaseous refrigerant from 
heat exchanger 30 through conduit 152, compresses it, and discharges it as 
a liquid to condenser 146, where it gives up its heat to the mash or raw 
water. The cooled refrigerant flows through conduit 153 to expansion valve 
154 which admits it to evaporator 30, where its transformation from a 
liquid to a gas cools the liquid in the evaporator. The electrical energy 
required to operate heat pump 147 is very considerably less than the 
amount of energy which would be required to raise the temperature of the 
mash in source 132 to the same extent by direct heating. 
It is to be understood that when the apparatus is being used for fractional 
distillation to produce alcohol, the end product is not intended to be 
absolute alcohol: the partial pressures of alcohol vapor and water vapor 
under vacuum are such that for a practical temperature of liquid mash they 
are equal when water vapor comprises about 7% of the total, and no pure 
alcohol is obtainable by this apparatus. Ninety-three percent alcohol is, 
however, a very satisfactory fuel for tractor engines and similar uses, 
and is readily obtainable from a suitable mash using the apparatus of the 
invention. 
From the foregoing it will be evident that the invention comprises a system 
for unattended distillation or fractional distillation, the system 
incorporating a novel vacuum pumping arrangement for maintaining the seal 
of a positive displacement pump when used to convey liquid and vapor at 
subambient pressures, and much of the energy required being derived from 
the temperature difference between a raw liquid and a treated liquid 
resulting therefrom. A great advantage of the system is its low cost of 
operation. 
Numerous characteristics and advantages of the invention have been set 
forth in the foregoing description, together with details of the structure 
and function of the invention, and the novel features thereof are pointed 
out in the appended claims. The disclosure, however, is illustrative only, 
and changes may be made in detail, especially in matters of shape, size, 
and arrangement of parts, within the principal of the invention, to the 
full extent indicated by the broad general meaning of the terms in which 
the appended claims are expressed.