Abstract: Automatic control systems, and corresponding processes, for controlling either an anode adjuster in a chlor/alkali cell or at least one average middle temperature of a distillation column wherein the combination of feedback control from at least one real unit operation variable and an embedded real-time dynamic simulation of that variable are used.

Abstract: A method and apparatus for forming an array of multiple parallel flow orifices, for example by holes drilled through a plate in a selected pattern and spacing and of selected sizes or flow diameters, and whereby these orifices are used to provide an approximately equal and adequate distribution of liquid flowing through them as parallel streams of liquid and into an evaporation zone or a parallel array of evaporation channels, and wherein the orifices can be adjusted in flow diameter to control the flowrate of liquid in generally parallel streams with an array of orifice adjusting apparatus, for example an adjacent sliding orifice plate which provides for orifice flow rate adjustment with orifices through this second plate corresponding in position to those of the first orifice plate, and the use of such dual orifice plates for supporting a pool of liquid there-above and for controlling the flowrate of liquid through the first array of orifices by reducing or enlarging their orifice flow diameters to control

Abstract: A method of separating water from an aqueous emulsion using a minimum of energy includes heating the aqueous emulsion in a sump, conveying concentrated emulsion from the sump to a heat exchanger so as to pass therethrough back to the sump, circulating water vapor and non-condensable gases from the sump through a compressor to raise its temperature and passing the heated water vapor and non-condensable gases through the heat exchanger to condense and heat the concentrated emulsion therein and evaporate water therefrom, a thermostat filled with water and water vapor, together with first and second pressure switches respectively communicating with the sump and the external atmosphere and the heat exchanger and the external atmosphere, maintaining a temperature differential between 0.5.degree. and 3.degree. C. between the aqueous emulsion in the sump and the temperature of the compressed water vapor and noncondensable gases.

Abstract: Improved kugelrohr or apparatus for distilling or separating liquids. It includes a rugged, reliable air oven and drive unit with numerous safety features. One or more external guards eliminate burn hazard and risk of accidental contact. A thermal isolation support isolates the oven from its rest surface. A grounded heating element eliminates shock hazards. The oven is fitted with a grommet or bushing to support a flask connected to one or more additional flasks in a series. The outlet of the last flask in the series is connected to a drive tube via a flexible coupling. The drive tube is connected to a rotary bearing assembly mounted on a drive unit. The oven and the flasks may include impellers for circulating air to enhance heating efficiency.

Abstract: A distillation solvent recycling system is provided which is characterized by improved safety features, modular construction, a double insulated solvent reservoir, electronic control and display of system parameters, and self diagnosis of system malfunctions. The components of the system are assembled into a compact unitized structure so as to maximize safety, efficiency, portability, convenience and ease of operation and maintenance. An outer insulative and protective safety casing shields the operator from process hazards while the system is in operation. An inner lid is provided with improved sealing mechanisms for preventing the escape of toxic solvent vapors. An outer safety lid shields the operator from heat and trace vapors in the vicinity of the solvent reservoir.

Abstract: An improved drinking water apparatus is provided which utilizes a microcomputer to detect water level to automatically control water intake and heating. The apparatus includes a heating tank having a heater at the bottom side, a first cooling pipe at the top of the heating tank, a distilled water tank, and a second cooling pipe located at the top of the distilled water tank and connected to the first cooling pipe. The cooling pipes are each provided with a cooling fan for cooking the steam generated by boiling water into distilled water. The temperature of the distilled water is lowered to a degree suitable for drinking purposes.

Abstract: A process and apparatus for the production of a beverage distills aqueous influent into a forerun overhead fraction that is the first result of a distillation operation, a distillate, and a bottom products fraction that is left over from the aqueous influent without being distilled. The forerun overhead fraction is removed, the distillate is sterilized and remineralized into the beverage, and the bottom products fraction is removed so the process can begin again with more aqueous influent.

Abstract: A water distilling apparatus includes a preheat tank having an inlet and an outlet for storing water from a water source via the inlet, a boiling tank formed of a conductive casing connected to a ground potential and having an inlet in connection with the outlet of the preheat tank, a heater located within the boiling tank to boil water thereby generating steam, and an outlet flue extending from the boiling tank through the preheat tank as to condense the steam and preheat the water within the preheat tank, a heat dissipation coil connected with the outlet flue out of the preheat tank, a fan blowing air against the heat dissipation coil, a cool water tank connected with the heat dissipation coil for storing condensed water therefrom, an electrode vertically extending into the boiling tank, electrically isolated from the case of the boiling tank and connected to a positive voltage source, a control circuit electrically connected to each of the electrode, the fan, and the heater for disconnecting the fan and th

Abstract: A system for decontaminating and separating individual refrigerants from a mixture of refrigerants contaminated with solids, liquids and non-condensible gasses, includes three stages. In the first stage, solid and liquid contaminants are removed. In the second stage, the mixture of refrigerants passes through a condensation column where successive condensation stages remove individual refrigerants from the mixture of refrigerants. The remaining mixture of refrigerants passes through a third stage where non-condensible gas contaminants are removed.

Abstract: In the method of optimizing the control of the mass transfer zone in distillation columns by their characteristic areas which are dependent on pressure and heating steam, the temperature is measured on two different theoretical plates in the mass transfer zone of the column. The measured values are compared with one of the characteristic curves of the characteristic areas, which represent the nominal values for the temperature and the distance between the points where the thermometers are installed in the column.

Abstract: A portable water distiller comprising a vaporization chamber containing an inclined electric coil heating element, a finned tube condenser coil and an electric fan. The heating element is provided with forward and rear portions, the forward portion being elevated relative to the rear portion with the thermostatic control means positioned above the forward elevated position and maintained in contact with the substantially uniform water level. Accordingly, when the uniform water level dips below the thermostatic control means, the heating element is immediately de-energized thereby preventing the residual heat in the heating elements from quickly evaporating the raw water in the raw water receptacle.

Abstract: A process and device for purifying organically polluted waste water utilizing a primary system and a closed secondary system. The primary system includes a first heat exchanger, a second heat exchanger and a cyclone located between the two heat exchangers. The first heat exchanger evaporates the waste water into a waste water vapor and a waste water sump solution. The heat for evaporating the waste water in the first heat exchanger is obtained primarily from raw water in the secondary system. A second heat exchanger in the primary system condenses the waste water vapor and in the process causes evaporation of raw water in the secondary system. The level of waste water in the primary system is monitored as is an operational parameter in the secondary system. With the data obtained from this monitoring, the drawing off of the waste water sump solution is controlled.

Abstract: The invention relates to an improved method and a novel apparatus for the concentration, separation, and purification of contaminated chemical compounds, wherein the chemical compound is less volatile than the contaminant. The distillation is performed using constant, predetermined distillation parameters.

Abstract: A method of optimizing the control of the mass transfer zone in distillation columns. Distillation columns are control optimized by controlling the steam feed, reflux, or pressure by determining the deviation from nominal values of characteristic curves of characteristic areas determined by measuring two different theoretical plates in the mass transfer zone of the column.

Abstract: A pollution control apparatus (10) for controlling water-based liquid waste includes a vacuum distillation vessel (14) for separating water-based liquid waste into a distilled water component and a pumpable sludge component. A pH control system (12) allows the vacuum distillation vessel (14) to operate at maximum efficiency, and a purification system (22) allows the distilled water component to be purified to a level capable for reuse in chemistry, or else suitable for direct discharge into a municipal sewer. A microprocessor allows the apparatus (10) to operate automatically.

Abstract: In a distillation column, which for control purposes cannot tolerate the inherent dead time between analysis of consecutive samples in chromatograph analyzers, the chromatograph output is frequently corrected by inferring a dynamic correction based on the temperature change of a selected tray in the column. The dynamic correction applied to the distillation analyzer essentially eliminates the inherent dead time for obtaining a chromatograph analysis, and accordingly increased the rapidity of response of the column controls which rely on chromatograph analysis.

Abstract: A water purification device mounted within a housing adapted to be positioned on an existing water cooler/dispenser has a valve control member extending from the base of the housing and is positionable within the water reservoir of the dispenser to control the release of purified water from the device to the reservoir. The device includes a feedwater tank into which supply water is fed and which feeds water to a water level control tank which communicates with the bottom of a boiler which is maintained at the same level as the water in the control tank. The control tank includes a control valve which maintains the water in it to a predetermined level above the level of the heating element in the boiler. The boiler is connected to condenser coils for condensing vaporized water from the boiler to form distilled water which is directed through a carbon filter to a distillate storage tank where the purified water is stored until required by the water cooler/dispenser.

Abstract: The invention relates to an improved method and a novel apparatus for the concentration, separation, and purification of contaminated chemical compounds, wherein the chemical compound is less volatile than the contaminant. The distillation is performed using constant, predetermined distillation parameters.

Abstract: A water distillation apparatus includes a cylindrical housing with a first cover thereon, a pair of spaced apart funnel-shaped partitions, a second cover on the uppermost partition and a skirt extending downwardly from the periphery of the cover and the uppermost partition to a location above the bottom of the housing, the partitions and skirt dividing the interior of the housing into an inlet reservoir chamber for cold water above the first partition, a lower boiling chamber beneath the second partition and an inclined condensation passage between the partitions. Cold water is introduced through a pipe and solenoid valve into the bottom of the reservoir chamber for overflow through an opening in the second cover into the boiling chamber. A heater in the boiling chamber heats the water to produce steam which rises, passing into the condensation passage and flowing downwardly to a central drain for discharge into a distilled water reservoir beneath the housing.

Abstract: A method of controlling concentrations in process technology operations--preferentially in thermal separation technology--using a non-linear, pressure-compensated temperature as control signal. The method can be used flexibly within a wide operating range.

Abstract: An automatic water heating and distilling apparatus is provided having a hot water reservoir, an evaporator tank, a condenser, a distilled water reservoir and a control mechanism. Water is boiled within the evaporator tank generating steam which is condensed in the condenser to form distilled water. The heat rejected during condensation is transferred into the hot water reservoir. The distilled water reservoir has an input coupled to the condenser, an output for distilled water, and an overflow so that excess distilled water is returned to the evaporator tank. The control mechanism automatically regulates the operation of a heater within the evaporator to maintain the water in the hot water reservoir within a selected operating range. Various alternative embodiments are also described including a hot water heating apparatus utilizing an enclosed heat transfer device partially filled with liquid having a boiling point above the selected temperature for the water to be heated.

Abstract: This disclosure relates to an improved solar water purification system and process wherein the evaporating, condensing and distillate collecting chambers are located underground to assist in the evaporation and condensation process. The system includes three computer controlled preheaters which are constantly monitored to determine the temperature of the load therein. The cycling and recycling of the load relative to the load tank and the three preheaters is controlled by the computer for optimum system efficiency. One of the three preheaters is located underground, while a second preheater is located externally as a solar preheater and the third preheater is an outside gas, oil or waste heat fired preheater. In addition to producing pure water through the evaporation process, there is disclosed a system and process whereby various contaminants may be captured for further processing, storage and exploitation.

Abstract: There is described an apparatus for distilling liquids in a vacuum, having a receptacle for a liquid that can be connected to a vacuum pump, a heating arrangement for heating the receptacle causing the liquid to evaporate, a condenser for condensing the vapour, and a collecting vessel for the condensate. To be able to handle the apparatus quickly and more simply and to make it overall more economical and make it possible to carry out continuous distillation, the heating arrangement includes a vacuum-tight receiving chamber (1) for the receptacle (2) and a microwave generator (13, 13.

Abstract: An apparatus for removing non-volatile residues and impurities from a used solvent includes a self-scrubbing heating distillation subassembly for separating purified solvent for reuse and a controlled waste collector subassembly for overflowing concentrated residues and impurities stripped from the used solvent into an easy-to-service container. The apparatus may be disposed in a parallel in-line relationship with a circulating solvent flow circuit, such as in a dry cleaning operation, to continuously withdraw and purify aliquot portions of the circulating solvent stream, returning good solvent back to the flow circuit and concentrating non-volatile residues and impurities to a removable, environmentally sound serviceable container.

Abstract: A method and apparatus are disclosed wherein a standpipe mounted in an accumulator outside the operating zone of a distillation column is used in conjunction with a liquid level controller to measure condensate collected in the accumulator and to change the amount of energy provided to the distillation column in response to changes in the level of condensate collected in the accumulator.

Abstract: The apparatus is located almost completely under the surface of the sea. The vacua in the de-aeration and the evaporation chambers are generated by a vacuum pump and are maintained by the effects of a pressure reduction device at the inlet for warm seawater and a lifting pump at the outlet for brine. The de-aerator and the evaporator are laid out as heat exchangers and penetrated by heating tubes, which are flowed through passively by warm seawater. The immersion tube forming the steam compartment which is suspended vertically in the sea serves as a condenser. The condenser is cooled passively by cold seawater. The attachment to the bottom of the sea is performed by a single point mooring construction via an anchor chain at an anchor weight. The elevation of the water production unit is controlled automatically by means of an air chamber and an air compressor.

Abstract: A method for the fractional distillation of a mixture of at least two compounds with different boiling points, a rising flow of vapor is brought into intimate contact with a descending flow of liquid obtained within a column (1) by the partial condensation of the flow of vapor itself by heat exchange with a cooled surface which extends through a filling (37).

Abstract: The concentrate holding lower portion of a sample and concentrate holding vessel has a jacket for shielding such concentrate holding portion from heat sufficient to volatilize appreciable solvent therefrom when the vessel is subjected to sufficient heat for effecting evaporative concentration of solution in such vessel.

Abstract: A water purification device mounted within a housing adapted to be positioned on an existing water cooler/dispenser has a valve control member extending from the base of the housing and is positionable within the water reservoir of the dispenser to control the release of purified water from the device to the reservoir. The device includes a feedwater tank into which supply water is fed, either automatically, or manually. The feedwater tank, when the water is above a minimal level, feeds water to an anti-backflow control housing which communicates the water from the feedwater tank to the bottom of a boiler which is maintained at the same level as the water in the feedwater tank without the use of a float within the boiler. The anti-backflow housing includes a check valve in the form of a ball that prevents the backflow of heated water from the boiler into the feedwater tank.

Abstract: To decrease the sulfur emissions of a sulfate cellulose mill, black liquor is heated before the last effect of the evaporation at a temperature higher than the cooking temperature of the sulfate cook and the sulfidity of white liquor is adjusted by adjusting the temperature and/or retention time of the heat treatment so that a predetermined amount of sulfur compounds are separated from the gaseous black liquor. Preferably, the sulfur containing gas is thereafter divided into different fractions and separately combusted.

Abstract: A coolant recycling apparatus has a boiler and condenser for distilling a glycol and water from a used coolant. The glycol and water are recombined in a mixing tank to form a mixture having a desired ratio of water to glycol, and an inhibitor is added to the mixture to obtain a fresh coolant mixture ready for use in an engine cooling system. Contaminants in the used coolant are concentrated to form a sludge.

Abstract: In a fractional distillation process which performs a binary or limited multicomponent separation, and in which it is desired to maintain composition set points for dual product streams, a computer is programmed for applying model based control. Multivariable, noninteracting control of the distillation process is achieved by utilizing a nonlinear model, which calculates process vapor and distillate flow rates required to maintain product set points. The model, which applies tray-to-tray calculation essentially derived from a McCabe-Thiele analysis, is periodically updated by adjusting tray efficiency based on steady state composition measurements to keep the model in pace with changing process conditions.

Abstract: A system for removing volatile constituents (e.g., hydrocarbons) from a liquid (e.g., water) containing the same by which there is a continuous countercurrent contact between the liquid and a forced air flow. Water collected in a reservoir is continuously pumped to the top of a stripping tower where it is dispersed downwardly over packing material. A blower forces air upwardly in the tower so as to remove the volatile constituents that exit the tower with the exit air. Since the water flow is continuous, multiple passes occur through the tower to enhance separation efficiency. Water from the base of the tower returns to the reservoir via overflow from a standpipe. A lower liquid level sensor in the reservoir initiates operation of the water pump to the tower, and an upper liquid level sensor initiates operations of another pump for pressure discharge from the base of the tower to an exterior site.

Abstract: A compact solvent reprocessing system for use in a limited physical area. Solvents to be reprocessed is contacted by deionized water in a water wash column and delivered to a distillation column where waste solvent is separated from materials that boil at a higher temperature than the waste solvent. Distilled solvent is delivered to a drying column and final filters for removal of any other foreign materials. The modular solvent reprocessing system to reclaim/recycle high purity solvents on-site at a manufacturing facility. A system includes a pumpless pressurized tank solvent transfer units, storage tanks, liquid-liquid extraction column, distillation columns, submicron filtration units, and water and acid adsorption columns arranged as necessary to produce ultra-high purity solvents from waste solvent streams. The systems are packaged in modular assemblies with secondary containment to meet U.S. EPA requirements.

Abstract: A distillation purifying system including a section which creates a vacuum pressure that is transmitted throughout the system, a distillation/purification zone in which fluids to be distilled/purified are treated, and a collection zone in which the distilled/purified liquids are transferred. The system is effective for use with liquids, solutions, fluids and the like and can be used for water treatment as well as bodily fluid treatment.

Abstract: A process for the separation of multicomponent systems containing intermediate boiling substances in separating separating columns with side discharge, the temperatures T.sub.u and T.sub.o above and below the side discharge are measured on the column or inside the column and the temperature difference T.sub.u -T.sub.o is used for controlling the side discharge. The control is carried out by constantly controlling one of the two temperatures T.sub.u or T.sub.o by the output of the evaporator or the discharge from the sump or the reflux or the removal of distillate or the reflux ratio.

Abstract: An improved distillation device (1) which uses a combination of centrifugal and positive displacement pumps to purify raw liquid in an area of limited space. The device (1) includes evaporation assembly (2) having a boiling chamber (5), a valve and float switches (15, 16, 17) for maintaining the liquid level (20) in the boiling chamber (5) at a predetermined level, and connecting conduit (21) for directing vapor to a condensation apparatus (3). The condensation assembly (3) includes a condensation chamber (6), a collection chamber (7), and at least one bubble tube (22) connecting the two chambers (6, 7). Leading from the collection chamber (7) is first transfer conduit (50), a tube (51) for permitting vapor to bleed from the collection chamber (7) back to condensation chamber (6), and second transfer conduit (52) for returning only distillate from collection chamber (7) to condensation chamber (6) to cool condensation chamber (6).

Abstract: A wastewater evaporator system is provided for evaporating wastewater at a rate of about seven gallons per hour. Such system includes a heater, a blower, a plurality of honeycombed plates, a drive element including an electric motor, and a tank. Such system improves the environment and allows safe, reliable, and economical disposal of wastewater.

Abstract: The centrifugal evaporator-concentrator includes a central tubular pivot (18) surmounted by a nozzle (35) and constituting the pivot axis of a rotor (9) rotating in a vessel (8) closed by a cover (11). With the rotor rotating in the partial vacuum created by a vacuum pump (33), a small quantity of gas or air is temporarily and periodically admitted into the vessel, this gas being heated by a heating resistor (38) inside the vessel for the purpose of heating by conduction the specimens to be concentrated and of accelerating the rate of evaporation.

Abstract: A distillation system where a saline fluid (10) is pumped into a pressure vessel (14), through a counterflow heat exchanger (16) and heated to boiling. A salt free distillate (20) is separated from the saline fluid (10). The concentrate valve (24) and the distillate valve (26) restrict egress flow. The concentrate valve (24), the distillate valve (26) and the heater (18) are controlled by a computer control system (32) to attain and maintain a desired value of the Ewing Number. The Ewing Number is a dimensionless measure of performance defined as the heat of vaporization of the distillate (20) at standard atmospheric conditions times the distillate (20) mass flow divided by the system power input.

Abstract: A system for the catalytic distillation production of alkylated aromatic compounds is provided wherein the vapor pressure of the olefin may be increased while maintaining the same olefin feed rate and aromatic to olefin ratio. In one embodiment a side stream from the vapor from the second column below the catalyst and olefin feed is condensed and rerouted to the aromatic make up stream from the reflux drum. The vapor pressure of the olefin in the lower end of the first column in the catalyst bed is thus increased which increases the equilibrium concentration of the olefin in the liquid phase. In another embodiment of the invention the effective driving force for the reaction is increased by injecting the olefin at different heights within the catalyst bed. If additional olefin is injected more catalyst bed height would be required, but the additional catalyst is more that offset by the increased throughput at the same overall olefin conversion.

Abstract: A method for water degasification and distillation in an apparatus having a container for a reservoir of water to be degasified and distilled, a relatively small boiler adjoining the container and having a feed water conduit connecting the container and boiler so that a selected water level in the container will fill the boiler to the same level, a coiled tube condenser within the container immersed in the water therein, the condenser coil having a vertically disposed longitudinal axis, a second conduit in the boiler connecting the space above the water level therein to the inlet of the condenser so that steam flows from the boiler to the condenser, an outlet on the condenser extending through a container wall for discharging the condensed steam as degasified distilled water, a heater in the boiler for heating the water therein, and a motor driven stirrer axially of the coiled tube condenser for generating a swirling movement of the reservoir water with formation of steam bubbles therein.

Abstract: A water distiller has a housing having an open interior area and a door that can be opened and closed to permit and block access into the interior area. A steam chamber is located in the interior area. The steam chamber includes a movable tray for holding water to be distilled. The tray seats against a fixed top where steam created in the chamber by heating the water in the tray is collected. By opening the door to the distiller, the tray can be unseated and removed for cleaning. After cleaning, the tray can be returned to the distiller and reseated against the top steam collecting portion by closing the door. In a preferred arrangement, the tray includes a chamber for holding a water soluble disinfectant for release during the distillation process.

Abstract: An evaporating process that alternate between different modes of operation, according to the characteristics of the product handled; the product is either force fed into the tube nest, or cascaded through it in a free-falling film.

Abstract: This invention is a continuous process for preparing phenol having improved clarity when dispersed in water. The phenol is prepared from crude phenol being the product of decomposition of cumene hydroperoxide and having previously been distilled to remove large portions of acetone, cumene and alphamethyl styrene.

Abstract: A water distiller has a steam chamber that includes a tray for containing water to be distilled. Water is conveyed from a source to the tray for distillation. A valve operates in an open position to convey water to the tray and a closed position to block the passage of water to the tray. A heating element means extends in the steam chamber for submersion in the water carried by the tray. The heating element is operable within a range of temperatures to heat the water in the tray. The heating element includes a main body portion having an axis that extends in a plane generally parallel to the water in the tray and a section havign an axis that is deflected above the axis of the main body portion. A heat sink surrounds the deflected section of the heating element means. A heat sensor detects the temperature of the heat sink. A control connects the valve and the heat sensor means. The control closes the valve when the sensed temperature of the heat sink is equal to or less than a predetermined amount.

Abstract: A disposal device for photographic processing waste liquor which concentrates the photographic process waste liquor by evaporation. The disposal device has a gas detecting device for detecting gas which may be generated during the evaporation of the waste liquor and a control device for stopping the evaporation based on the detection of a concentration of a specific gas. The processing method for photographic waste liquor involves evaporating the waste liquor to concentrate it and detecting gases which are generated during the evaporation process. When the concentration of a specific gas reaches a certain level, the evaporation step is halted.

Abstract: A method and apparatus for automatically and sequentially distilling batches of water having substantially equal volumes in a plurality of distillation cycles, one batch in each cycle. During each cycle, water is admitted to a boiler tank for a fixed interval of time to form a batch in the tank. The batch of water in the tank is then vigorously boiled while venting the tank through a pipe to the atmosphere. The vigorous boiling is terminated when the temperature within the vent pipe reaches the boiling point of pure water. Upon termination of the vigorous boiling phase, a gentle boiling phase is initiated, the vent pipe is closed, and vapor in the tank is admitted to a condenser. The condenser condenses the vapor to obtain distilled water which is collected in a collection device. The gentle boiling phase continues until the level of water in the tank recedes to the level of a heater in the tank.

Abstract: Apparatus and methods for determining the Reid Vapor Pressure of either an overhead, side draw or bottoms product stream of a fractionating column used for fractionating a multi-component hydrocarbon feed stream into an overhead product stream, a side draw product stream and a bottoms product stream are provided. The Reid Vapor Pressure of the particular product stream is determined in response to the temperature of the product stream, the vapor pressure of the product stream, the rate of flow of the bottoms product stream, the rate of flow of the overhead product stream, and/or the rate of flow of the side draw product stream without further analyses thereof. The Reid Vapor Pressure indication is used to maintain the actual Reid Vapor Pressure of the particular product stream substantially equal to the desired Reid Vapor Pressure of the particular product stream and to thereby control the quality of the desired product stream.

Abstract: A control for a water distillation apparatus admits untreated feed water to the boiling tank in response to a demand for the production of distilled water and operates the heater to produce steam. Level probes in the boiling tank monitors the level of untreated water in the boiling tank and admits more feed water as necessary. When demand for production of distilled water has ceased, the heater is deenergized and the boiling tank is filled to dilute the residual water in the tank and lower its temperature prior to drainage to prevent damage to a plastic house drain. In a preferred embodiment, feed water is admitted to the boiling tank in large batches and the production of distilled water continues uninterrupted until the entire batch is distilled to conserve heat energy even if demand ceases during such batch distillation. A cleaning mode is provided to remove scale from the interior of the boiling tank with a simplified manual cleaning procedure.