US 3345271 A
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PRESSURE 1967 J. H. SHAY ETAL 3,345,271
FLASH DISTILLATION BOILER FOR TREATING MINERAL WATERS INCLUDING TEMPERATURE RESPONSIVE MEANS Filed Nov. 30, 1965 ATTORNEYS United States Patent ABSTRACT OF THE DISCLOSURE In summary the invention involves a system for removing minerals such as salt from Water and producing purified water. Impure water ispumped by a feed Water pump through feed water passages of a condenser and thus preheated. It is then discharged under pressure through a spray nozzle or nozzles into a flash boiler heated by an electric heater. Salt is removed from the boiler by blowdown. Steam from the boiler is carried through steam passages of the same condenser and then removed by a purified water discharge.
The feed water pump is controlled by a pyrometer in the boiler so that operation of the feed water pump ceases when a minimum boiler temperature is reached.
Description. of invention The present invention relates to a system for purifying water by removing minerals such as salt from it.
A purpose of the invention is to produce a very simple and inexpensive system for purifying water in which the feed water in the impure feed water passages of a condenser is heated and then is sprayed into a flash boiler Where it instantaneously forms steam, the steam passing through steam passages of the condenser and there being condensed to produce purified water.
A further purpose is to use the impure feed water to condense the steam and provide purified water from the flash boiler.
Further purposes appear in the specification and in the claims.
In the drawings we have chosen to illustrate one only of the numerous embodiments in which the invention may appear, selecting the form shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.
FIGURE 1 is a diagrammatic vertical section of the device of the invention.
FIGURE 2 is an electrical diagram.
Many highly developed and relatively complicated evaporative systems for desalting water are available, as for example, that shown in Wilson U.S. Patent 3,147,598, granted Sept. 8, 1964, for Apparatus for Evaporating Impure Water.
The present invention is concerned withthe production of very inexpensive equipment for distilling Water to purify it. In the mechanism of the invention a flash boiler is used in which the steam is almost instantaneously generated from a spray of water, and the steam is condensed by the cooling effect of the feed water which is shortly to be sprayed into the boiler.
Considering the drawing in detail, We there show a fiash boiler 20 having an inlet 21 and a discharge 22. An emergency blow-01f valve is provided at 23.
The bottom of the boiler slopes at 24 to a sump 25 in which salt collects, and the salt is removed by opening normally closed blowdown valve 26. If there is difficulty through excessive dryness of the mineral, this can be corrected by introducing additional water in the boiler before blowdown.
3,345,271 Patented oer. 3,1967
The boiler is heated by an internal electric heater 27 connected to external terminals 28 and 30 through insulating seals 31 Well known in the art.
At the outlet 22 there is preferably provided a pressure release valve 32, although this is not necessary, and the system will often be operated as an open system. From the pressure release valve 32 steam passes by pipe 33 to steam passages 34, suitably a steam coil, in the interior of a condenser 35. Cooling applied by the condenser condenses the steam, and it discharges through a purified water discharge 36.
The water to be purified enters at 37 at the inlet end of a feed water pump 38 driven by an electric motor 40. Discharge from the pump passes by pipe 41 to the cooling water jacket portion 42 of the condenser 35, surrounding the steam coil 34. Feed water is removed from the cooling jacket portion 42 suitably at the bottom by pipe 43 which connects at the inlet 21 to the boiler 20 with spray nozzle or nozzles which introduce a spray of water into the boiler preferably upon the heater 27. 7 As shown in FIGURE 2, power lines 45 and 46 are connected to the electric motor 40 for driving the pump through pyrometer switches 45 and 46 controlled by a pyrometer 44, which are open when the temperature is too low for injection of Water into the boiler and cut off water from the boiler. The heater 27 is in continuous operation when the device is functioning.
In operation, starting with the boiler 20'cold and the device not in operation, the power lines 45 and 46 are connected to the device, energizing the heater 27in the boiler.
Prior to injection of water into the boiler, the boiler is heated up suitably to a temperature of 450 to 500 F. In
the preliminary test boiler this took about 15 minutes.
When the boiler reaches a temperature of 450 F. or the temperature at which the pyrometer 44 is set to operate, the pyrometer closes the switches 45 and 46 energizing motor 40 to drive pump 38. This pumps impure water from pipe 37 through pipe 41 and the cooling water portion of condenser 35 and then through pipe 43 into the spray nozzle or nozzles 40 for spraying a fine stream of water into the boiler and preferably onto the heater 27. Steam is almost instantaneously formed and evolves through the outlet 22 and the pipe 33 assuming that the valve 32 is constantly open. If the valve 32 is closed, steam does not evolve until a pressure is reached such as 50 psi. which opens valve 32. The steam is condensed in steam coil 34 of the condenser and forms purified water which passes out of the system through discharge pipe 36, which may if desired flow to a distribution system or to a storage tank.
Periodically, depending on the mineral content of the water, the blowdown valve 26 is operated to discharge the mineral deposit 25 to waste. If the mineral content is heavy, blowdown should be operated at least once each day, and if the mineral content is extremely heavy, blowdown should be operated every few hours.
If necessary, to render the mineral content liquid or dispersible, prior to blowdown excess water can be introduced into the boiler, as by disconnecting the pyrometer temporarily and closing the switches 45 and 46.
It will be evident that in normal operation, if excessive water is introduced, the temperature of the boiler will lower and the pyrometer Will open switches 45 to 46, cutting olf the operation of the pump drive motor 40 and avoiding introduction of Water until such time as all water in the boiler has been converted to steam.
Unlike the usual type of boiler, which is likely to explode if it runs dry, the boiler of the present invention is capable of operating without burning out the heater 27 notwithstanding that the boiler is dry.
If there is a problem of excessive boiler temperature, electrical fuses can be employed which are responsive to boiler temperature and will disconnect the heater in case the temperature of the heater rises excessively far beyond the desired temperature range.
In view of our invention and disclosure, variations and modifications to meet individual whim or partciular need will doubtless become evident to others skilled in the art,
to obtain all or part of the benefits of our invention without copying the mechanism shown, and we therefore claim all such insofar as they fall within the reasonable spirit and scope of our invention.
Having thus described our invention what we claim as new and desire to secure by Letters Patent is:
1. In a system for removing minerals from water, a flash boiler having an inlet and an outlet, blowdown means for removing minerals from the boiler, electric heating means for heating the boiler, a condenser having feed water passages and steam passages in heat transfer relationship with one another, piping connecting the steam passages of the condenser at one end with the outlet from the boiler, a feed water pump connected to one end of the feed water passages of the condenser, electric motor means for driving the feed water pump, electrical switch means in circuit with electric motor means, a spray nozzle in the boiler connected to the other end of the feed Water passages of the condenser, a purified water discharge connected to the other end of the steam passages in the con- References Cited UNITED STATES PATENTS 2,471,035 5/1949 Hurd 159-3 X 3,055,810 9/1962 Skow 20310X 3,212,997 10/1965 Walker 2033 3,252,501 5/1966 Loebel et al 202236 X 3,269,923 8/1966 Roche et al. 203 X 3,294,649 12/ 1966 Powell 203-10 3,298,931 1/1967 Herbert et a1. 203-10 X FORETGN PATENTS 392,044 5/ 1933 Great Britain.
NORMAN YUDKOFF, Primary Examiner.
WILBUR L. BASCOMB, JR., Examiner.
F. E. DRUMMOND, Assistant Examiner.