Advances In Desalination:

The Aul EGD Process


Robert A. Nelson

Electro-Gravitational Desalination ( EGD )

A simple method of desalting ocean water now exists which uses no external energy, and produces electrical power at the same time! This revolutionary process, called Electro-Gravitational Desalination (EGD), makes it possible to recover as potable water more than 80% of the saline or brackish water treated with the process. It also produces at least enough electrical power to operate pumps to keep the system flowing.

According to Albert Aul (email inJanuary 2003), the Aul EGD process is currently "dormant" because:

(1) "It was discovered that the gap between anode and cathode had to be maintained at 0.25 inches for the process to oeprate. This created a design and maintenance problem that limited the cost effectiveness of any equipment built, regardless of size.

(2) " Marine micro-organisms, such as gallionella, attacked copper voraciously: numerous test units were literally detroyed by them (chlorine does not appear to kill such organisms.

(3) "Most importantly, the development activity ran out of funds. Given the above described difficulties, a prolonged and expensive effort to overcome them was not to the best interest of the funding sources, and the work was abandoned."

Accordingly, the following information is presented with the suggestion that only the construction of a 1-gpd unit be attempted as a survival apparatus that can be cleaned manually, without concern for cost efficiency.

As human population increases, fresh water resources are being depleted rapidly due to waste, pollution, declining water tables, and subsequent salting-up (increased concentrations of dissolved minerals) of ground water, rivers, etc.. This makes desalination increasingly necessary and cost-competitive with the transportation of fresh water over long distances. Some 900 desalination plants with a total capacity of almost 300 million gallons/day are located throughout the world today.

Several processes have been developed for desalination of water. Distillation is the oldest and most common desalination process in use. Other processes include: solvent extraction, electro-dialysis, reverse osmosis, propane extraction, freezing, and ion-exchange systems. All of these methods consume large amounts of energy that alters the economics of desalination. But the cost of transporting fresh water is increasing, so desalination remains cost-competitive.

The new method of Electro-Gravitational Desalination (EGD) is the discovery of Albert H. Aul, who received U.S Patent # 3,474,014(Cl. 205-150) and several foreign patents for his invention.

Electronic coagulation of saline solutions has been developed since the early 1940s, but such systems employ strong direct current. The Aul EGD system requires no externally applied energy; rather, it generates its own electrical power. It is in effect a salt-water battery in addition to its desalination applications. Aul explains EGD as follows:

"The principle upon which EGD is based is galvanic to the extent that a 'primary' (not rechargeable), low-power battery is galvanic. In any EGD system (as in any battery), each cell contains two electrodes: a copper anode and an aluminum cathode. The electrolyte (dilute sulfuric acid in a storage battery, but only sea water in an EGD unit) 'connects' the electrodes at one end, but in order to complete an electric circuit it must be connected at the other end as well, and in order not to deplete the 'battery very quickly (as would be the case if the electrodes were connected only with a wire and no 'resistance' --- called a short-circuit), some resistance (or 'load') must be added, such as lights, or a motor or other devices, in the connection between the electrodes at the other end.

"Electricity is produced by chemical action, and in the case of an EGD unit using copper anodes and aluminum cathodes, oxygen and aluminum are the materials that react with each other, and hydrogen is the catalyst. In plain terms, a catalyst is a substance that causes other substances to become unstable and recombine to become stable. Aluminum and oxygen, when in contact, without the presence of hydrogen, will remain independent and stable, but in the presence of hydrogen will combine, releasing electrons. Water is hydrogen and oxygen. When in EGD the aluminum and oxygen combine, the hydrogen goes off mostly as a gas.

"In the EGD systems as described, no other electrode-metal reactions with materials in the water have been measured or observed. However, with the electrical field that exists, the particles of salts (chlorine, sodium, bromine, magnesium, and every other substance attached to the water molecules) become attracted to the electrodes. The field generated by the EGD system is stronger than the field that holds these particles to the water molecules; thus the copper anode electrode attracts the positively charged particles (anions), and the aluminum electrode attracts the negatively charged particles (cations), the particles or ions being molecules too, but composed of only atoms that each represents. Sea water, for example does not contain sodium chloride (table salt); chlorine and sodium ions are individually attached to the water molecule. In nature they only combine when the water molecule has been evaporated away, and there is no 'occupied' water molecule to become attached to. In EGD, these ions become detached because of the electrical field.

"In EGD the field strength is really unimportant, as long as a field exists. We make up for that lack of a field strength of a copper/aluminum EGD device by flowing the water through a large number of cells. The number of cells and the flow rate dictates the rate of desalting and the amount of saline material remaining in the water after it has gone through EGD processing. There are limitations on flow rate for each design, and there are minimum numbers of cells for each design. The maximum number of cells is dictated by the builder of the EGD devices; there is a point in each design where the amount of matter removed in relation to the cost of the cells is so small that it becomes impractical to have the extra cells.

"As the materials (ions of various salts) accumulate adjacent to the electrode surfaces, and the water's laminar flow downward along the electrode surfaces carry the ions out of the field, much of the ion material becomes reattached to water molecules not in the field (they redissolve), forming a dense brine. That water from which the saline ions have migrated, now is unburdened and less dense than the saline water. The desalinated (desalted) water occurs in the center of the gap between the electrodes and is "bouyed" up by the denser saline water below, so that the desalted quantity is to be found at the top, center-of-gap location of each cell.

"Only about 30% of the EGD process depends on chemical reactions. For this reason the initial urge of technical persons to analyze the process using conventional electro-chemical thermal balance equations should be subdued. The well-known phenomena of the behavior of matter ions in solution between a non-reactive cathode and non-reactive anode, more closely represents the facts, except that the electrolyte is not an electroplating medium, and that the system is galvanically disposed by a minimum reaction of cathode (aluminum) and electrolyte-borne oxygen/hydrogen, rather than with applied energy from an external source."

Of the 30% of the EGD process that includes chemical reactions, many of the materials are released as gases such as hydrogen, chlorine, and others. Hydrogen and chlorine also recombine to form hydrogen chloride, which reacts with calcium carbonate to produce precipitant calcium chloride and free hydrogen. Some of the liberated ions of sodium, calcium and magnesium recombine with the carbonate radicals disrupted from calcium carbonate and form respective carbonates and hydroxides. (Figure 1)

Because most of the salts are removed by EGD rather than by reducing the electrodes, the electrodes last a very long time and require only periodic cleaning. The cathode reduction rate is calculated at 0.0013 oz. avoir. of aluminum hydroxide for each 100 gallons of water desalinated. The average value of current produced is 0.000022 amp/sq. in. of cathode surface in contact with saline water being processed.

Albert Aul describes a very simple model that can be constructed to demonstrate the principle of EGD:

"Two metal plates, one of aluminum and one of copper, approximately 2" x 3" x 1/16" thick, are drilled with two 1/4" diameter holes in the top corners of both plates. Insert wood dowels through the holes so as to support the plates about 1/2" apart in a wide-mouthed jar of about 3-pint capacity. Connect the electrode plates with a short piece (about 5") of insulated wire, to both ends of which are soldered alligator clips. Fill the jar with ordinary tap water in which is dissolved about 1/2 gram of table salt. Then add a few milligrams of thymol blue pH indicator. Adjust the pH with a minute amount of very dilute acetic acid (vinegar) and sodium hydroxide (lye) until the water turns an orange color. Any additional acetic acid will increase the pH and produce a bright red color. Additional lye will change the color to clear yellow. The apparatus now is complete."

The two plates are electrically connected using the wire and clips, thereby establishing a galvanic cell of the type described by Albert Aul. After several minutes a noticeable change becomes apparent: the copper plate becomes blanketed with a thin layer of dark red color, and the aluminum plate is covered with a thin yellow layer. As the copper anode attracts positive ions and decreases the pH in its area, the indicator turns bright red in that region. The pH increases around the aluminum cathode and the indicator changes to a yellow color in that zone as the negative hydroxyl ions accumulate there. Within ten minutes the colored layers become about 1/16" thick on each side of the metal plates. Then streams of red and yellow fluid can be seen coming off the bottom of the metal plates and extending to the bottom of the jar. As the operation continues, the colored zones increase at the bottom of the jar. After several hours of operation, small flecks of aluminum hydroxide form on the aluminum cathode.

"The indicator changes color because the positively charged (electron-deficient) hydrogen atoms are attracted to the copper anode, and the negatively charged hydroxyl ions are attracted to the aluminum cathode. In the same manner, the dissociated salts yield positive ions of sodium, magnesium, and calcium that are attracted to the copper anodes while the anions of chlorine, carbonates, and hydroxides are attracted to the aluminum cathode. As the solution of ions increases near the plates they establish a gravitational convection flow in which the denser fluid layers containing higher concentrations of salt ions settle to the bottom of the jar, leaving the fluid zone between the electrode plates depleted of dissolved salts, i.e., desalinated."

The construction of a practical EGD system requires certain constraints. For instance, the gap between the aluminum and copper electrodes must be 1/4", with only a narrow margin for variation. If the gap is too narrow, it short-circuits as chains of aluminum hydroxide build up and bridge between the electrodes. If the gap is too wide, the electrochemical potential is too low and insufficient to the electrochemical reaction threshold. Also the water must enter the system within the electrode zone, not below it, as indicated in Figure 2. The following is a description of a preferred embodiment of the Aul EGD process:

"Four tubular copper anode containers were connected in such a manner as to permit saline water to be introduced a distance from the bottom of one tube, then permitted to flow out of the top of that tube into the next tube, where the inlet was in the identical location of the first, and so on for all four tubes. The distance from the bottom of the containers to the inlets was sufficient not to impede the deposition of the precipitants nor cause the incoming water to be mixed with the precipitants.

"Tubular aluminum cathode elements were then suspended into the tubular anode containers. The cathodes were connected together by... an insulated wire. The anodes were connected together by an insulated wire, and then connected to one side of a meter calibrated to be read in milliamperes. The cathodes were connected to an electrical resistance of 10 ohms. The electrical resistance was connected to the other side of the ammeter.

"The axes of the copper anode containers and the aluminum cathodes were coaxial and oriented perpendicular with the earth's surface. The total capacity of the system was measured at 2.7 gallons of water. At the bottom of each container a stopcock was provided for the removal of precipitants.

"Saline water was introduced and permitted to flow continually through the system at a rate of 2.7 gal./day. the water was tested. The total dissolved and solid saline materials were 36,000 ppm of water before the introduction into the process, and only 370 ppm after ejection from the system, indicating about 99% desalination. The precipitants were removed as a dense brine which measured 104,000 ppm of suspended solids for each 2.7 gallons processed."

After sea water containing about 15,000 ppm of dissolved or suspended solids has passed through a series of about a dozen Aul EGD cells, its saline content has been reduced to about 250 ppm. This is good drinking water. If the water is used for agricultural purposes, a higher saline content is acceptable.

In 1965, Louis Shaffer, chief of the Reclamation Bureau's Division of Hydrology at San Bernardino, tested an Aul EGD plant which processed water from the Salton Sea to yield desalted water about equal in quality to kitchen tap water in San Bernardino. Shaffer said:

"It's a revolutionary approach to the age-old problem of converting sea water to fresh water in the arid regions of the world."

The Aul EGD process has become a dormant technology since the death of the inventor. This elegant technology now awaits further development, and a thirsty society awaits its implementation. Following herewith are Albert Aul's US Patent # 3,474,014 and construction plans for EGD units with 1 gallon/day and 100 gpd capacity. As stated at the beginning of this report, only the construction of a 1-gpd unit can be recommended as a survival apparatus...


1.  Aul, Albert H.: U.S Patent # 3,474,014 (Cl. 204-150), 21 October 1969; "Electro-Gravitational Desalination of Saline Water"
2.  Stuart, Fred E.: "Electronic Coagulation"; Public Works (April 1947), pp. 27-36.
3.  Murphy, George W., & Batzer, David: "Apparatus for Studying Electro-Gravitational Separations"; J. Electrochem Soc. (December 1952), pp. 520-526.
4.  Luce, Capt. J.D.: U.S. Coast Guard Trip Report (12 January 1966):"Visit to   General Marine Technology Corp."
5.  U.S. Bureau of Reclamation Report (23 April1965/3 May 1965):"U.S. Salinity Lab Water, Untreated & Desalinated Salton Sea Water, & Sea Water Comparison with City of San Bernardino Water."
6.  San Francisco Chronicle; 5 July,1965
7.  Hoblscher, Prof. Erwin C.: "Analysis of Desalination Process Proposed by Mr.  Albert Aul"; Supplementary Report (17 January 1969).

Foreign Patents Issued to Albert Aul for EGD:

Australia # 435,486 (62,235/69), 10 May 1973.
Belgium # 740,506 (20 October 1969).
Canada #909,716 (12 September 1972).
France # 2,063,974 (69-35684), 17 October 1969).
Great Britain # 1,271,829 (20 October 1969).
Israel # 33,147 (28 September 1972).
Italy # 1,045,106 (10 May 1980).
Japan #792,258.
Sweden # 343,282 (15 June 1972).

Figure 1: ElectroGravitational Desalination ~

Figure 2: EGD Cell ~

U.S. Patent # 3,474,014

Electrogravitational Desalination of Water
U.S. Cl. 204-150 (Oct. 21, 1969)

Albert H. Aul


Electrogravitational method of desalination of salt water using two dissimilar metal electrodes connected externally which form a galvanic couple creating current flow through the system. Portions of salts that are attracted to the electrodes establish concentrated areas of higher density that settle to the bottom of container whereby the solution removed from the bottom is of a greater concentration than the water thereabove.

This process removes the saline materials from saline water for the purpose of making the water potable and useful for agriculture without ill effect.

The novelty of this invention is that it requires no application of energy from any source external to the process; that it incorporates no critical or strategic materials and that it is completely self-contained.

Existing desalination processes require the application of heat energy or electrical energy from an independent source to make the process operational, whether for direct separation of saline material from water by electrolytic means using applied electricity, distillation of steam or evaporated water, operation of pumps and other equipment necessary to such processes.

This invention produces its own electrical energy as well as making it possible to recover more than 80% of the volume of saline water injected into the process, as desalinated water.

Minerals such as aluminum and alloys of aluminum and other minerals react with saline materials that are dissolved and suspended in saline water. These chemical reactions cause the saline materials to combine with the minerals placed in the water for that purpose. The chemical reactions cause a change in the energy levels of various atoms in the reacting molecules.

When non-reacting minerals such as copper, alloys of copper or other minerals are placed at a distance from the reacting minerals with an unobstructed quantity of saline water between the reacting and non-reacting materials, an electrostatic field is caused to exist.

The mineral in contact wit the saline water and reacting with the saline water is called the cathode. The mineral in contact with the saline water and considered non-reacting is termed the anode. When the cathode and anode are placed at a distance from each other with an unobstructed quantity of saline water in contact with the surface of each, and when an electrically conductive material is placed so that it continually is in contact with both the cathode and anode, but not in contact with the saline water, an electric current is caused to exist. The rate of chemical reaction, production of electrical energy and rate of separation of the saline materials and their removal from the saline water are proportional.

Saline water tested by this process was obtained from the Pacific Ocean having a content of dissolved and suspended solids 44,000 milligrams per liter of water of which 6400 milligrams of the same solids were CaCO3 (calcium carbonate). After processing per this process, wherein the reaction was controlled to accomplish a separation of saline materials of approximately 70% of the amount contained in the saline water, analysis of the processed water showed that the total of solid materials remaining dissolved and suspended in the water measured 10,660 milligrams solids per liter of water. Of these solids 1,530 milligrams were calcium carbonate. The control was subsequently adjusted to cause more separation and removal of saline materials; the resulting analyses showing the processed water to contain 650 milligrams per liter of water of solid matter, of which 320 milligrams were calcium carbonate.

The reacted materials do not adhere to the cathode but disengage as their density increases and fall to the bottom of the vessel in which they are contained. Non-reacting materials suspended in the water being processed become charged in the electrical field between the cathode and anode. Each particle will then be attracted to the next as their respective negative and positive poles come into opposition. Ultimately the accumulated density exceeds their former buoyancy as a result of the coalescence by attraction and these materials deposit at the bottom of the vessel in which they are contained.

The electric current produced as a by-product of the desalination process chemical reaction was measured to have an average value of 0.000022 ampere per square inch of cathode surface in contact with the saline water being processed. For each combination of cathode and anode the electromotive force as measured to be 0.5 volt. The rate of separation and removal of saline materials from the water, termed desalination, has been calculated. The calculations are based on the amount of material separated and removed from the water, the observed change in measurement of electric current and the amount of water processed. The rate of desalination of one cubic inch of saline water in contact with the surfaces of one cathode and one anode of one square inch area, where the cathode and anode are in mutual contact with an electrically conductive material not in contact with the water, is two minutes for water having a content of 650 parts  of solid material in suspension and solution per million parts of water after processing from an original state wherein 44,000 parts of solid material in suspension and solution per million parts of water were measured before processing.

By analysis 31,675 parts of cathode materials were reacted and removed from the cathode for each million parts of water processed, where the processed water contained 650 parts of solid material in suspension and solution for each million parts of water.

The material separated and removed from the water by the desalination process described herein, are removed from the bottom of the vessels in which they are deposited, and made available for processing into chemical, metals, chemical products, metal products, and all other uses to which they are applicable. Many of the materials released by the chemical reactions of the process are released as gases, such as hydrogen, oxygen, chlorine and others.

These gases partially combine in the water, small portions of chlorine gas dissolving. Hydrogen and chlorine combine to form hydrochloric acid that in turn reacts with calcium carbonate resulting in free hydrogen gas and precipitant calcium chloride. The hydrogen gas expands out of the water to atmosphere.

The chlorine gas is released when the sodium chloride molecule is disrupted by the electrochemical reactions of this process. As the chlorine atoms are recombined as described in the foregoing so does the sodium atom combine with the carbon atoms of the disrupted calcium carbonate molecule resulting in precipitant sodium carbonate and sodium hydroxide.

For a clearer understanding of the invention, specific examples of the invention, specific examples of the invention are given below. These examples are merely illustrative ad not to be understood as limiting the scope and underlying principles of the invention.

Example I:

A tubular container of copper was constructed into which a cylindrical rod of aluminum was suspended coaxially. The aluminum cathode was connected to the copper anode with an electrical conductor.

The entire assembly was oriented with the axes of the cylindrical parts perpendicular to the earth’s surface. Saline water was introduced into the anode container. The saline water had a content of dissolved and solid saline matter of 35,00 parts per million of water.

The distance by which the surfaces in the container and the cathode rod were separated was 0.75 inch. The water was permitted to remain in the container one hour. After one hour the water was removed and tested. The remaining dissolved and suspended solid material was measured at 28,900 parts per million of water.

Example II:

Four tubular copper anode containers were connected in such a manner as to permit saline water to be introduced a distance from the bottom of one tube, then permitted to flow out of the top of that tube into the next tube where the inlet was in the identical location of the first, and so on for all four tubes. The distance from the bottom of the containers to the inlets was sufficient not to impede the deposition of the precipitant nor cause the incoming water to be mixed with the precipitants.

Tubular aluminum cathode elements were then suspended into an anode container. The cathodes were connected together by an electrically conductive material. The anodes were connected together by an electrically conductive material. The anodes were then connected to one side of a meter calibrated to be read in millamperes. The cathodes were connected to an electrical resistance of 10 ohms. The electrical resistance was connected to the other side of the ammeter.

The axes of the anode containers and the cathodes were coaxial and oriented to be perpendicular with the earth’s surface. The total capacity of the system was measured at 2.7 gallons of water. At the bottom of each container a means was provided for the removal of precipitants.

Saline water was introduced and permitted to flow continually through the system at a rate of 2.7 gallons per day. This produced 0.05 amperes of electrical current at an electromotive force of 0.5 volts continually. The water was tested. The total dissolved and suspended solid saline materials were 36,300 parts of water before introduction into the process and 370 parts per million parts of water after ejection from the process. The cathode reduction rate was calculated at 0.0013 ounces avoirdupois of aluminum lost for each 100 gallons of water desalinated. The precipitants were removed as a dense brine that measured 104,000 parts per million parts of water of suspended solids for each 2.7 gallons processed.

The present invention in its broader aspects is not limited to the specific minerals, mechanizations and examples described, but also includes within the scope of the accompanying claims any departures made from such minerals, mechanizations and examples which do not sacrifice their chief advantages.

What is claimed is:

1. The process of desalination of salt water which comprises flowing such water between spaced-apart, substantially vertically arranged dissimilar metal electrodes in a cell-like means, the electrodes being connected by an electrical conductor outwardly of the water, whereby an electric current flows between them, attracting, by such flow of current, portions of the salts to each electrode, whereby to cause an increase in density of water adjacent to each electrode, permitting settlement downward from adjacent the electrodes to the bottom of cell-like means, and removing from the bottom a brine of greater concentration than that of the water thereabove.

2. The process as defined in claim 1 together with the subsequent steps of flowing the upper portions of such water between electrodes of further cell-like means, and repeating the remainder of the steps so set forth, whereby to effect progressive desalination


566,324  (8/1896)  Kendrick  (Cl. 204-150)
2,451, 067  (10/1948)  Butler  (Cl. 204-248)
3,342,712  (9/1967)  O’Keef  (Cl. 204-148)

U. S. PATENT No. 3,474,014


Electrogravitational Desalination of Saline Water (EGD), is a process designed for the desalting of sea water to produce potable and agricultural water as a supplement to existing water supplies, for application in sea coast communities.

The invention operates much the same as a storage battery except that there are a great number of cells, and the electrolyte (sea water), continuously flows through the system. The amount of residual salts left in the product water is controlled by the flow rate; the faster the water flows the more is left in it, conversely the slower the water flows the more is removed, however, for each design there is an optimum flow rate and a minimum flow rate. The average minimum flow rate should never fall below one gallon per day for any system, but for larger systems this figure is even too low. The rule of never permitting the system flow rate to be less than 10% of the designed optimum flow rate in units over 10 gallons per day is best to follow.

Although some ion exchange takes place in the system and is the source of the by-product electrical power that is generated, most of the saline matter is removed by the electrogravitational phenomenon. Between the rods (the cathodes) and the tubes (the anodes), an electrical field comes into existence when tube and rod are connected together electrically (outside of the electrolyte), with some kind of resistance load (light bulbs, or motors, etc.) between. The electrolyte forms the other “connection” between the rod and tube. The dissolved salts are, in fact, ions (atomic sized particles) with positive or negative charges, attached to the water molecules. The electrical field in the EGO process causes these ions to be detached from the water molecules and migrate to either the anode or cathode, depending on the charge of the ion.

The ions accumulate at the surfaces of each (rod and tube), but only the Oxygen and Hydrogen ions will react with the materials of which the rods and tubes are made, and in the case of the designs contained in these instructions, only the rods are consumed over a long period of time. The rest of the ions (the salt ions) accumulate at the rod and tube surfaces, gradually being drawn downward by gravity until these reach the space below the rod (where there is no electrical field), where these redissolve (the ions become reattached to the water molecules), forming a dense brine. To this brine is added the hydroxides formed by the ion exchanges (reactions) between rods and those ions we mentioned before. These hydroxides are in the form of flakes and whitish in color. These flakes are only slightly more dense than the water, and though most will fall to the bottom, some will stay suspended in the water and usually filtered out before the product water is used. These hydroxides are harmless, being in fact one of the two constituent materials used in treating digestive tract ailments in products bearing trade names of Maalox, Di-Gel, etc. The main ingredients of these products are aluminum and magnesium hydroxides, of which ours is aluminum hydroxide.

Other beneficial side effects of EGD operation include the release of chlorine ions, which expand out of the water as a gas (rising to and out of the water's upper surface), some, of course, is carried down with the other materials. The gaseous chlorine destroys harmful organisms. All but trace amounts of chlorine are usually removed from the product water by aerating before storage, as it comes from the output filter.


These instructions contain basic information for the construction of two different units; a unit that will produce 100 gallons per 24 hour day of water containing 400 parts per million total dissolved solids, from saline ocean water containing 30,000 parts per million total dissolved solids from which suspended matter has been removed by filtration to ten microns, and a one gallon per 24 hour day unit producing water of the same quality as that specified for the 100 gallon per day unit from the same source .

The designs have been developed to permit the builder to obtain materials that are commercially available from hardware stores, plumbing supply centers, lumber supply centers and retail metal products suppliers. Significant latitude has been allowed to facilitate substitutions as well as permitting the builder to fully decide on certain materials as well as size of materials and parts. Where strict limitation was necessary in material selection, and dimensions they are clearly identified. The designs have been developed from fully tested and demonstrated laboratory devices.

Construction of tube assemblies for both types of units only differs in size. Rod assemblies for the two differ in construction due to the very small diameter of the one gpd unit's rods. The one gallon unit is intended to be an emergency device only, the design does not lend itself well to prolonged use as it is a hand filled unit, and when not in use must be disassembled completely, and all parts thoroughly dried (after removing all traces of saline water by rinsing in fresh water). The following instructions give more on the subject of storage .


100 gpd:

Figure I illustrates a vertical side view with partial cut-away to show cell (tube and rod, assembled), position and identify certain components as well as construction fundamentals. The solenoid shown is for lifting the perforated plate that pushes the valves open momentarily to dump the waste brine. The dumping need only be done once each day, and for no more than a half second of time. A hydraulic cylinder may be used instead, but this requires a motorized pump. The cylinder may be preferable over the solenoid in order to get the force needed to raise the valves against nearly 800 lbs. of water weight, but this is a decision the builder must make based on equipment availability. The schedule for Figure I is on the page following.

Figure II gives the recommended construction dimensions for the housing. Items 9 and 14 on Figure I need not be mounted to their support angles, but can be laid on them. The lid should be locked into position only to prevent shifting and dislocation that would adversely affect rod/tube alignment and electrical connections. The method of locking is optional. Inlet and outlet pipes are not shown or specified on the housing. The builder has the option as to which way these should project from the unit (whether out the ends or the sides), keeping in mind that the inlet of water to the tubes is at the bottom and the outlet at the top.

Figure IIA shows the location of two sets of holes that correspond to the mounting positions of the rods, and the tabs for making the electrical connections to the tubes. The .201" diam. holes are for mounting of the rods to the lids as well as making the electrical connections to the rods. The .250" diam. holes are for passing the wires from the tube electrical connection tabs out onto the lid top where the connections can be made. The frame for the valve plate lift ropes and lifting mechanism support is also shown on Figure IIA . Standard fiberglass sheets come in a maximum size of 4' x 8'. These can be cemented together with a wide strip of the same material to obtain the larger dimensions recommended in these instructions, using epoxy cement (2 part is recommended).

Figure III and its associated schedule illustrate the assembly of the tubes for the system. The recommended spacing center to center of each tube in both directions is 2-1/2" (from centerline of a tube to the centerline of its neighbor tubes). The inlet and outlet direction is shown for illustration purposes only, and as stated are optional.

Figure IV and its associated schedule illustrate tube constructions. All the materials recommended are those in use for transfer of potable water (drinking and cooking water). It is recommended that the builder use only those materials, and not materials that might be contaminating.

Figure V illustrates rods for both 100 gpd and one gpd units. Details VI - X should be carefully examined. Detail VI and Detail VIII should be drilled in line with the .201" diam. holes in Figure IIA, which in turn must align with the tube array.

Detail VIII supports the tube array and is drilled to permit the valve stems to hang down. Detail VI maintains tube alignment and separation at the top of the tubes, while allowing the tabs to clear.

Detail IX calls out perforated plastic sheet, but expanded metal sheet that has been completely coated with a well bonded coating without obstructing the perforations so that the waste water may pass through, may be preferred. The plate must lift the valve stems against approximately 800 lbs. of water weight, without permanently deforming.

Figure XI illustrates the electrical connections recommended; 1) connections are series connections that add the voltage of each cell so connected to the next, and 2) connections are parallel connections that add the current values of the cells so connected. Per the recommended connections shown, an average total of 997 Watts will be available. This power is ample for operating a water pump motor 1/4 hp to 1/3 hp), for filling the unit, at a constant rate. If it is preferred by the builder that the power be first converted from the DC produced to AC, it must be kept in mind that some power loss will result in such conversion. It is recommended that the builder employ a power panel containing a wattmeter and switching so that power stability can be monitored. Power drop-off is directly related to reduction in desalting activity, and is usually due to the rods having become coated with hydroxides. This condition can be corrected without shutting the unit down, by employing a hand held ultrasonic generator, and touching each tube for a few minutes to "shake-off" the hydroxide materials. Care must be taken not to cause an electrical short or to be subjected to electrical shock during this process. It is recommended that the ultrasonic device be fully electrically insulated. The rods can be vibrated through their mounting screws.

One gpd:

Figure XII illustrates the recommended container for a one gallon emergency use device. Figure XII and its associated schedule are considered clear enough to permit construction of such a device, employing the other applicable parts of this instruction (Figures IV, V, XI and their associated schedules), and the general recommendations given herein.

Figure XII - Item 10 is the top plate of the base box. This plate supports the rods and is where the electrical connections should be made. The electrical leads can be connected to a "jack" type socket on the side of the housing (base box), from which a number of items can be operated if fitted with mating plugs. Some of the possible devices are: an emergency transceiver radio, light, emergency radio transmitter beeper. The device will produce an average 0.98 Watts, ample in a number of the devices mentioned. As shown on Figure XII, the lid assembly is also the filling reservoir. Again, as in the 100 gpd unit, the builder has the option of the outlet location, as well as the inlet to the first cell. The outlet should have a valve so that the flow can be controlled, but when flow is controlled at the outlet, extra care must be taken to prevent overflow of the tubes from filling with more water than is being allowed to pass out. Corrosion and electrical shorts can result that would seriously effect the desalting capability of the device.


If a unit is stopped for any reason, it must be drained of all saline water, the electrical circuit opened (switched off), the cell components thoroughly rinsed and dried (fresh water rinse). If the units are to be stored after having been used, stopped and dried, the rods should be removed from the cells and stored separately. Some corrosion of the tubes may occur in storage, or a patina may form in them. Providing that such storage is not for an exceptionally long period that might seriously damage the tubes, the unit can usually be put back into operation very quickly by filling the tubes with any of the liquid copper cleaners generally available to remove the corrosion products .The cleaner must be thoroughly rinsed out of the system before using the system again. The rods should be cleaned to remove all oxides and expose bare metal. Electrical connection points should be carefully inspected and corroded parts cleaned or replaced .

The desalting unit should be filled with filtered sea water taken from far enough offshore to minimize the pollutant content. The finer the filtration, the lower the risk of potential troubles. Petroleum contaminants for instance, can cause very frustrating contamination that will obviously stop the process from operating effectively.

These units should be operated in as motion free an environment as possible. Agitation of the water in the tubes will cause mixing which totally defeats the process function. Too high a flow rate will cause turbulence that results in the same problem. The one gallon unit can be used in life boats as long as there is relative calm, or as long as internal "sloshing" can be prevented.

The waste brine tank in the bottom of both units must be fitted with a means for removing the brine periodically. To monitor the level, a clear plastic window can be cemented into the housing wall, and a manually operated drain valve installed. The brine can be evaporation dried and its salt content recovered .

SCHEDULE FOR FIGURE I      [ # Required / gpd]

1)      108" x 78" fiberglass sheet (3/16" to ½" thick)    [1 / 100 ]
2)      Figure IV tube assembly      [ 660 / 100 ]
         Figure IV tube assembly      [ 48 / 1]
3)      Figure V rod        [ 660 / 100 ]
         Figure V rod        [ 48 / 1 ]
4)      #8-32 x 1" round hd. machine screws     [ 660 / 100 ]
         #5-40 non-conductive, non-corrosive hex. nuts   [ 192 / 1 ]
5)      Detail IX (can use fully epoxy coated expanded metal)   [ 1 / 100 ]
6)      1/4""std. thd. eye bolts w/nuts      [ 4 / 100 ]
7)      1/4" marine quality nylon rope    [ approx.600 ft. / 100 ]
          " " " " "       [ 15 ft. / 1 ]
8)      DC (or optional AC) 1" stroke vert.mnt. solenoid.  [ 1 / 100 ]
        (must lift min. 1000 lbs .)
9)      Detail VI fiberglass sheet (3/16" to 3/16" min. thick)   [ 1 / 100 ]
10)      3" x 6" x 1/4" aluminum angle (paint with epoxy)   [ 48 ft. / 100 ]
11)      2" x 2" x 1/4" aluminum angle (paint with epoxy)    [ 144 ft. / 100 ]
12)      3" x 3" x 1/4" aluminum angle (paint with epoxy)   [ 28 ft. / 100 ]
13)      104" x 84" fiberglass sheet (3/16" min. Thick)    [ 2 / 100 ]
            84" x 74"   " " " " "       [ 2  / 100 ]
14)      Detail VIII fiberglass sheet (3/16" to 1/2" thick)    [ 1 / 100 ]
15)      Detail VII 1/2" P\/C or ABS pipe, and elbows (cementable)  [ as req. / 100 ]
16)      72" x 102" fiberglass sheet (min.3/8" thick, double-up 3/16"
            cementing pieces together at edges to prevent leaks)  [ 1 / 100 ]
17)      3" x 6" x  1/4", aluminum angle (paint with epoxy)  [ 13 ft. / 100 ]
18)      1/4" - 20 x 4" bolt with min. g' thread length    [ 4 / 100 ]
19)      1/4" - 20 hex. nut for above bolts, with lock washers  [ 4 / 100 ]
20)      2" spacers (cut from tubing, or drill cut round -Alum.)  [ 4 / 100 ]
21)     1/4" aluminum plate 6" x 32"     [ 1 / 100 ]
22)      Detail X; 1/4" -20 x 36" threaded round   [ 2 / 100 ]
23)      Detail X; 1/4" -20 hex. nuts & lockwashers    [ 4 / 100 ]
24)      Detail X; 1/2" O.D. (min. 3/8" I.D.) tubing, 30-1/2" lg.  [ 2 / 100 ]


For 100 gpd unit:

A ~ 30 rows of cells interconnected as shown
B ~ 23 cells per row, with transition connections made per Detail VII
C ~ Salt water inlet into bottom of first cell
D ~ Desalted water outlet from top of last cell
E ~ Cell inlet
F ~ Cell outlet

NOTE: Connect first cell and next cell outlets to adjacent cell inlets for 659 cells (last cell's outlet is outlet D).

For 1 gpd Unit:

A ~ 8 rows of cells interconnected as shown
B ~ 6 cells per row, with transition connections per Detail VII
C )
D ) Same as above (100 gpd schedule)
E )

NOTE: connect first cell and next cell outlets to adjacent cell inlets for 48 cells (last cell's outlet is outlet D).


1)  Plastic pipe "T" (PVC orABS), cementable, modify for achieving dimension-A, if necessary:
       for 100 gpd -- 1" x 1/2"                                                   1320 required
        for 1 gpd = 3/4" x 1/"                                                     96 req.

2)  Plastic pipe:  for 100 gpd = 1/2" dia. (PVC/ABS)               360 ft. req.
        for 1 gpd = 1/4"dia. (PVC/ABS)                                      40 ft. req.

3)  Plastic pipe' el' (PVC/ABS), cementable, modify for achieving dimension -A, if necessary:
        for 100 gpd = 1/2"                                                            1320 req.
        for 1 gpd = 1/4"                                                                96 req.

4)  Copper tubing:
        for 100 gpd = 1" diam x 0.03 wall x 64" lg.(3520 ft.)         660 req.
        for 1 gpd -- 3/4" dia. x .06 wall x 18" lg. (72 ft)                 48 req.

5) Plastic pipe:
        for 100 gpd -- 1" dia. (PVC/ABS) x 2" lg. (110 ft.)           660 req.
         for 1 gpd = 3/4" dia. (PVC/ABS) x2" lg. * ft.)                  48 req.

6) Plastic (PVC/ABS) closure caps drill thu to fit 7:
        for 100 gpd -- 1" cementable                                              660 req.
        for 1 gpd --- 3/4" cementable                                                48 req.

 7)  Standard faucet washer:
        for 100 gpd --                                                                    660 req.
        for 1 gpd --                                                                         48 req.
        Note: Must seat and seal hole in 6 without binding, but leak free

7) 2" long bolt selected to fit hole in faucet washer:
        for 100 gpd --                                                                      660 req.
        for 1 gpd ---                                                                        48 req.

8) 2" long bolt selected to fit hole in washer:
        100 gpd --                                                                            660 req.
        1 gpd --                                                                                48 req.

9) Hex nuts to fit bolt 8:
        100 gpd --                                                                            1320 req.
        1 gpd --                                                                                 48 req.

10)  #6 self-tapping screw, 3/8" long:
        100 gpd --                                                                             660 req.
        1 gpd --                                                                                 48 req.

11)  3/16" wide x 1" lg. X .03 max thick, screw mounting electrical wiring link:
        100 gpd --                                                                            660 req.
        1 gpd --                                                                                48 req.

Dimension A:  for 100 gpd = 2-1/2" ; for 1 gpd = 2"

Dimension B:  for 100 gpd = 1-1/2" max.; for 1 gpd = 1-1/2" max.

Dimension C: for 100 gpd = 2"; for 1 gpd = 2"

Dimension D:  for 100 gpd = 3/4"; for 1 gpd = 3/4"

Dimension E:  for 100 gpd = 1/2" dia.; for 1 gpd = 1/4" dia.


1) 3" x 3" aluminum angle x ¼" thick (epoxy paint), 22 ft. req.; make frame so that fiberglass sheet attach inside

2) Lid: top & bottom of lid must be assembled and sealed to lid frame as a box, and so assembled that the fill pipe just enters the gap between the rod and the tube without binding or causing spillage. Lid "box" is salt water reservoir for and filling thru 6" diam. hole.

3) Bottom support plate, 1/8" min. fiberglass sheet, 1 req.

4) Fiberglass sheet for sides, bottom and lid: approx. 25 sq. fr., 1/8" min. thickness

5) 1" x 1" x 1/8" aluminum angle, 30 ft. required: when preparing assembly with items 3 & 9 & 10, arrange so that disassembly can be achieved with ease (screw mount support ledges only. Short pieces on which these plates can be laid then screwed in place.).

6) Seal this 19" x 15" x 1/8" thick min. fiberglass sheet to box as reservoir for waste brine. A drain pipe must be added, with a valve out of box side, to permit waste brine removal.

7) [Missing in plans]

8) Epoxy coated expanded metal sheet for valve lift, 1 req.

9) Tube holding plate, 1 req, 1/8" fiberglass sheet.

10) Rod holding plate, 1 req., 1/8" fiberglass sheet.

Figure I: Elevation, 100 gpd assembly ~

Figure II: Elevations, 100 gpd unit housing ~

Figure IIA: Top View, 100 gpd housing ~

Figure III: Tube array plan & tube connection data ~

Figure IV: Tube assembly construction ~


Figure V: Rod assemblies construction ~


Details VI: Figure X:

Figure XI: Electrical Connections ~ 

Figure XII: Housing for 1 gpd unit ~ 

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