Drinking Water Filter

SUMMARY OF THE INVENTION

In view of the foregoing, it is a primary object of the subject invention to provide an improved water filter used for various household uses. Also, the water filter can be used in commercial and industrial applications where treated drinking, cooking and washing water is desired or required. The water filter provides a consumer with protection against major water contaminants found in municipal water supplies.

Another object of the invention is the water filter removes the contaminants in the water to below E.P.A. recommended minimum levels.

Yet another object of the invention is the water filter is designed to remove large and small sediments in the water. Also, the filter removes chlorine, trihalomethanes, hydrogen sulfide, pesticides, herbicides, toxic heavy metals, (such as lead, organic mercury, organic arsenic and others), cysts, protozoa, (including giardia and cryptosporidium), cancer-causing organic pollutants, micro-organisms and other foreign particles and organisms. The subject invention gives treated water a sparkling clarity by screening material out of the water down to a one micron in size.

Still another object of the invention is the filter is designed to raise the water's pH, thereby lowering acidity and increasing alkalinity, which is recommended by many nutritionists.

A further object of the water filter is no plumbing is required in its use. The water filter is received in a filter housing which is attached to a standard water faucet. The filter housing can be disposed on a counter top for household use. Also, the water filter housing can be attached to a water supply line and mounted under a kitchen sink.

Another object of the invention is the water filter costs pennies per gallon, is compact and space saving in design and eliminates the need to buy, lift and carry heavy water bottles. The water filter has a filter life of treating 1500 gallons of tap water, which is a typical one year average drinking and cooking water use of a family of four. The water filter includes a replaceable filter cartridge which can be quickly and easily replaced.

The filter includes a cylindrical filter cartridge with a number of filter layers therein. The filter cartridge is adapted for receipt in a water filter housing connected to a municipal water supply. The filter cartridge includes an upper filter cap with water inlet in fluid communication with a tap water supply to the filter housing. The upper filter cap is received inside an open top portion of the cartridge. The cartridge also includes a lower filter cap with a water outlet. The lower filter cap is received inside an open bottom portion of the cartridge.

The cartridge further includes a plurality of filter pads which may be used as dividers between different layers of filtration material and along a length of the cartridge. The filter pads are designed to remove large and small sediments in the water from 1 to 100 microns in size and greater when the water is introduced through the cartridge.

In an upstream upper portion of the cartridge is layer of a granulated zinc and copper alloy. The zinc and copper alloy is known in the trade by a brand name of KDF-55. The zinc and copper alloy is used for removing chlorine and some heavy metals in the water. Also, the alloy is an excellent bacteriostat for reducing bacteria in the water.

In a center portion of the filter cartridge is a layer of granulated activated carbon. The activated carbon is used for removing chlorine, odor and color from the water being filtered. Also, the activated carbon removes organic contaminants such as pesticides, herbicides, arsenic, mercury and trihalomethanes, a cancer-causing organic pollutant.

Downstream from the layer of granulated activated carbon is a layer of a granulated ion exchange resin. The ion exchange resin has an exceptional affinity for lead and removes this contaminant to below minimum E.P.A. standards.

In a downstream bottom portion of the cartridge is a layer of granulated calcite. The calcite may be used in the filter to raise the water's pH. This feature lowers the acidity of the water and increases the alkalinity, which many nutritionists recommend.

The last stage of the filter is a one micron absolute depth filter material made of polypropylene or like material. The one micron filter material screens out cysts and protozoa, which includes giardia and cryptosporidium. Also, by filtering the water through the one micron filter material, the water is given a sparkling clarity.

These and other objects of the present invention will become apparent to those familiar with the water filters and water filtration equipment when reviewing the following detailed description, showing novel construction, combination, and elements as herein described, and more particularly defined by the claims, it being understood that changes in the embodiments to the herein disclosed invention are meant to be included as coming within the scope of the claims, except insofar as they may be precluded by the prior art.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing illustrates complete preferred embodiment of the present invention according to the best modes presently devised for the practical application of the principles thereof, and in which:

FIG. 1 is a perspective view of the subject water filter with the filter cartridge in an upright position. A portion of a cartridge housing has been cutaway to expose and illustrate the various granular materials used in filtering the water to be treated. Arrows are shown at the top of the cartridge to illustrate the incoming unfiltered water. Also, additional arrows are shown at the bottom of the filter cartridge illustrating discharged treated water.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, a perspective view of the subject water filter is shown having a general reference numeral 10. The water filter 10 includes a cylindrical hollow filter cartridge 12 shown in an upright position. The cartridge 12 is adapted for receipt inside a filter housing which is connected to a tap water supply line. The filter housing and the water line are not shown in the drawings. The filter housing may be a free standing unit for receipt on top of a kitchen counter top or may be mounted under a kitchen sink or like installation.

The cartridge 12 includes a cartridge housing 14. The cartridge housing 14 includes an upstream upper portion 16, a center portion 18 and a downstream lower portion 20. A portion of the cartridge housing 14 in FIG. 1 has been cutaway to expose and illustrate the various layers of granular materials and filter pads used in filtering the water as it flows therethrough.

Also, the cartridge 12 includes an upper filter cap 22 with a water inlet 24. The water inlet 24 is in fluid communication with the tap water supply line. The upper filter cap 22 is received inside an open top portion 26 of the cartridge housing 14. The cartridge 12 also includes a lower filter cap 28 with a water outlet. The lower filter cap 28 is received inside an open bottom portion 30 of the cartridge housing 14. The water outlet is centered on the lower filter cap 28 and is hidden in this drawing and therefore not shown. In this drawing, arrows 32 are shown at the top of the cartridge 12 to illustrate the incoming unfiltered water from the water supply line. Also additional arrows 34, illustrating the discharged treated water, are shown leaving the water outlet in the lower filter cap 28.

The filter cartridge 12 further includes a plurality of filter pads which may be used as dividers between different layers of filtration material and along a length of the cartridge housing 14. A first filter pad 36 is designed to remove large solids and sediments such as rust. The pad 36 is typically a 100 micron sponge filter but can be in a range of 50 to 150 microns for screening large particles and floating solids in the unfiltered water.

In the upstream upper portion 16 of the cartridge 12 and below the pad 36 is layer of a granulated zinc and copper alloy 38. The zinc and copper alloy 38 is known in the trade by a brand name of KDF-55. The zinc and copper alloy 38 is used for removing chlorine and some heavy metals in the water. Also, the alloy 38 is an excellent bacteriostat for keeping bacteria from growing inside the cartridge 12.

Disposed below the layer of alloy 38 is a second filter pad 40. The second filter pad 40 is typically a 10 micron felt pad for removing smaller floating solids in the water. The pad 40 can be in a range of 5 to 20 microns for screening small particles out of the water.

In the center portion 18 of the cartridge 12 and below the second filter pad 40 is a layer of granulated activated carbon 42. The activated carbon 42 is used for removing chlorine, odor and color from the water being filtered. Also, the activated carbon 42 removes organic contaminants such as pesticides, herbicides, arsenic, mercury and trihalomethanes, a cancer-causing organic pollutant.

Disposed below the layer of activated carbon 42 is a third filter pad 44. The third filter pad 44 is typically a 10 micron felt pad for removing fine sediment in the water. The pad 44, similar to the second pad 40, can be in a range of 5 to 20 microns for screening small and fine particles out of the water.

Downstream from the layer of granulated activated carbon 42 and below the third filter pad 44 is a layer of a granulated ion exchange resin 46. The ion exchange resin 46 has an exceptional affinity for lead and removes this contaminant to below minimum E.P.A. standards.

Disposed below the layer of ion exchange resin 46 is a fourth filter pad 48. The fourth filter pad 44 is typically a 10 micron felt pad for removing fine sediments in the water. The pad 48, similar to the second and third pads 40, 44, can be in a range of 5 to 20 microns for screening additional small and fine particles out of the water.

In the downstream bottom portion 20 of the cartridge 12 is a second layer of granulated activated carbon 42. The second layer of activated carbon 42 provides additional protection in removing chlorine, odor, and cancer-causing organic pollutants from the water.

Disposed below the second layer of activated carbon 42 is a fifth filter pad 50. The fifth filter pad 44 is typically a 10 micron felt pad for removing fine sediment in the water. The pad 48, similar to the other above mentioned felt pads and can be in a range of 5 to 20 microns for screening additional small and fine particles out of the water.

Below the fifth filter pad 44 is a layer of granulated calcite 52. The calcite 52 may be used in the filter 10 to raise the water's pH. This feature lowers the acidity of the water and increases the alkalinity.

The last stage of the water filter 10 is a one micron absolute depth final filter 54. The final filter 54 is made of cellulose or like material. The one micron final filter 54 screens out cysts and protozoa. Also, by filtering the water through the one micron final filter 54, the water is given a sparkling clarity. The final filter 54 is disposed above the lower filter cap 28.

While the invention has been shown, described and illustrated in detail with reference to the preferred embodiments and modifications thereof, it should be understood by those skilled in the art that equivalent changes in form and detail may be made therein without departing from the true spirit and scope of the invention as claimed, except as precluded by the prior art.

AIR FILTRATION

AIR FILTRATION

---

THEORY AND BACKGROUND

Airborne Particle Characteristics

Airborne contaminants pose a constant threat to our environment. Man and nature both foul the air with particulate and gaseous pollutants. Despite efforts to control emission of these pollutants, the air around most large cities still contains billions of particles per cubic foot of air. A great many of these are dangerous to plant and animal life. Clean air is dependent upon a reduction of these particulate levels.

The following information is provided to give a basic understanding of the characteristics of particulate matter.

Particulate Matter

For our purposes , particles are defined as bodies with:

1. Definite physical boundaries in all directions.
2. Diameters ranging from 0.001 micron to 100 microns.
3. Liquid or solid phase material characteristics.

A micron, or micrometer, is a measure of length in the metric system. One micron equals one-millionth (1/1,000,000 or 0.000001) of a meter. In English units one micron equals 1/25,400 inch.

EXAMPLES:

1. 1 inch = 25,400 microns (or 0.000039411 = 1 micron).
2. Eye of needle (1/32 inch) = 749 microns.
3. The dot of an "i" (1/64 inch) = 397 microns.

Particle Visibility

The ability to see an individual particle depends on the eye itself, the intensity and quality of light, the background and the type of particle. The particles seen on furniture or floating in a ray of sunshine are in the range of 50 microns or larger, although 10 micron particles can be seen under favorable conditions. A beam of light is visible due to the light scattering effects produced by a multitude of particles present in the air. In this manual, 10 microns has been chosen as a conservative dividing line between larger. visible and smaller, invisible particles.

Particles smaller than 10 microns are visible under a microscope. Electron microscopes can resolve particles down to 0.001 micron. Particles as small as 0.01 micron are demonstrably removable by an electronic air cleaner although theoretically it will remove particles down to 0.001 micron.

The majority of invisible particles are 3 microns in diameter and smaller. If these smaller particles are present in vast numbers, they are usually visible as a pollutant due to their light scattering quality. For instance, a wisp of cigarette smoke is actually composed of tiny particles (0.01 to 1 micron) which are too small to be seen individually. As soon as the smoke particles disperse, they are no longer visible.

Visible particles (less than 10% of the total airborne particles by count) tend to settle on horizontal surfaces of furniture, floors and shelves where they can be removed by a dust cloth, mop or vacuum cleaner. Invisible particles can deposit on vertical as well as horizontal surfaces. In industry, this contributes to the soil and grime that collects on walls, windows, machinery and clothing, forming potential health hazards as well as maintenance problems.

Particle Weight and Density

In ambient air, 99% of airborne particles by count are less than 1 micron but contribute only 20% of the total particle weight. The remaining weight comes from a rather small number of particles up to 100 microns in size. Industrial processes generate particulate, adding to material already suspended in the air. The "smoke" they generate usually consists of high concentrations of particles less than 10 microns (typically, 60% are less than 2 microns).

Standard filter media can remove particles above 10 microns very effectively. As particle size decreases to 5 microns, 2 microns and on into the sub-micron range, mechanical particulate removal systems become increasingly expensive to operate at high efficiency. It is in this range that the electronic air cleaner performs best, yielding high collection efficiency at a very low expenditure of energy.

Particle Settling Factor

The rate at which particles of the same density (same weight per volume) settle out of the air is an important factor affecting the performance of air cleaning equipment. In a room with an eight foot ceiling, the time necessary for particles to settle out of the air can be dramatic.

Particle Settling Times

Many 10 micron and larger particles settle out of the air before they reach the air cleaner. About 5 to 10% (75 to 90% by weight) settle in the rooms and never reach the air cleaner. Particles less than 1 micron have masses so small that gravity is seemingly neutralized. Their settling velocities are so low that they are easily affected by air movement from hot working machinery and plant circulation systems. These particles are also subject to Brownian motion, i.e., erratic movement of particles in a fluid (in this case, air). Brownian effects become dominant on particles less than 0.3 micron in size, where their random motion keeps them almost indefinitely suspended in the air. By continuously recirculating plant air through an air cleaner, or series of cleaners, a high efficiency of small particle removal can be attained. By capturing the particles at the generation source, an even higher efficiency can be achieved, usually with less air cleaner capacity.

Respirable Fraction

Industrial hygienists are concerned about airborne particulates and their effect on the welfare of workers. The human body is a marvelous filter mechanism, but vulnerable to heavy concentrations of small particles. Some particles are particularly dangerous to the human anatomy since they can become trapped for long periods of time, or even permanently.

Some particle size ranges have been identified as areas of special attention. Particles 10 microns and below fall into the "inhalable fraction" range, i.e., those particles small enough to pass through the body's standard filtration mechanisms and deposit. Particles below about 2.5 microns constitute the "respirable fraction", i.e., that percentage of particles which can be trapped in the human lung or even find their way into the blood stream. Potential chemical reactivity, surface reactivity and immunological effects make these particulates extremely dangerous. Two stage electrostatic precipitators, with peak efficiencies in the inhalable and respirable fraction range, are useful tools in industrial particulate emission control.

Particulate Adhesion and Soiling Effects (Housekeeping)

Particles under 1 micron in size are suspended in the air until they deposit on some type of surface. They deposit on vertical and underside surfaces such as walls and ceilings, as easily as they do on floors. Once deposited, they are imbedded or attached to that surface by molecular adhesion so that manual cleaning is the only way to remove them. Examples of this include oily residue on machinery, discoloration and dirt build-up on walls and light fixtures, and thick layers of powdery residue in welding shops.

The Electronic Air Cleaner

The electronic air cleaner is technically referred to as an electrostatic precipitator. An electrostatic precipitator is a device which ionizes, or charges, then collects, particulate suspended in a gas stream. The term "electrostatic" is used even though the mechanism of removal is dynamic rather than static. This term evolved because of the close relationship between the physical behavior of the device and the general field of static electricity that exists in it. Credit is given to two modem day pioneers, F. G. Cottrell in the United States and Sir Oliver Lodge in Great Britain, for developing the single stage precipitator for particulate removal in industries such as blast furnaces, reverberatory furnaces and power plants. In 1933, Dr. Gaylord Penney developed the two-stage electrostatic precipitator-the type most commonly used today in commercial and industrial process applications.

Theory of Electrostatic Particle Attraction

Common electrical phenomena, such as a comb attracting bits of paper or dry clothes that cling to the body, (occurrences normally ascribed to static electricity), illustrate the attractive force employed in electronic air cleaners. Under normal conditions, particles in the air tend not to exhibit visible attraction to one another because they are electrically "neutral," carrying little, if any, charge.

In the example of the comb and bits of paper the rubbing of the comb changes the electrical balance, or polarity," and causes the comb to attract the paper. In the same manner, an electronic air cleaner actively alters the electrical balance of particles in the air by imparting a high positive charge to those particles. The particles' tendency to be repelled by other positive surfaces and to be attracted by negative surfaces is radically intensified. These phenomena occur because the materials involved have different electrostatic charges, or polarities, with respect to one another. However, none of the above exhibit a visible attraction for any of the others without special treatment. They are usually electrically neutral because each one tends to be balanced electrically and has very little, if any, charge. Rubbing the objects disturbs the electrical balance and creates a slight mutual attraction between them.

How Electronic Air Cleaners Work

A two-stage electrostatic precipitator is constructed in two sections-a charging, or ionizing, section and a collecting section. The charging section contains a series of fine wires suspended between metal plates; the collecting section is a series of parallel, flat metal plates spaced about a quarter inch apart. The entrained particles are first given an electrical charge by the ionizer. They are then collected on plates which have an opposite charge in the collection cell.

The Ionizing Section

When observed in darkness, a pale violet glow appears around the fine wires of the ionizer when it is operating. This is a visible indication of a corona discharge in the air immediately adjacent to the wires. It is in the area of this discharge that the electric charges are produced for the particles to be collected. The intense electrical activity which occurs in this area may be explained as it applies to the charging of particles in an electronic air cleaner. According to electrostatic theory, when a continuous DC voltage is applied to a fine wire suspended between grounded metal plates (a large surface in relation to the wire), a nonuniform electrostatic field is formed in the inter-electrode space (on both sides of the wire between the grounded plates). The field is said to be non-uniform because it is very strong near the wire, decreasing rapidly, as distance from the wire increases, to a relatively low value at the surface of the grounded plates. By increasing the voltage on the wire, field strength is proportionately increased. Eventually, depending upon wire size, wire shape and distance from wire to plate, corona starting conditions are reached and air (gas molecules) near the wire is forced to undergo an electrical change

A molecule is the smallest portion of any substance that can exist and still retain the chemical characteristics of the substance. Each molecule includes protons that carry a positive electrical charge and electrons that carry a negative electrical charge. The negative charges of the electrons are all of the same value and in an electrically neutral molecule their sum equals the sum of the positive charges of the protons in the molecule. But if one or more of the electrons is knocked out of the molecule, for instance by collision with a foreign electron, the molecule is left with a surplus of positive charge and then is called a positive ion. If the positive ion is in an electrostatic field, it will be propelled toward the negative side of the field. The freed electron will be propelled toward the positive side of the field. The propelling force will be proportional to the gradient of field intensity. "Free" electrons (those not attached to atoms) exist everywhere, even in a vacuum. Within the non-uniform electrostatic field in an electronic air cleaner, free electrons are accelerated toward the positively charged wire. The velocity becomes very great as they pass through the increasingly higher fie!d intensity in approaching the wire. On their way, many free electrons strike air molecules and knock other electrons out of them. The dislodged electrons then accelerate toward the positive wire, in turn knocking more electrons free from other molecules. In this way a vast number of positive ions are created and they move rapidly toward the grounded plates. The electrons attracted to the wire tend to neutralize the positive charge on the wire, but are prevented from doing so by the continuously supplied current from a highvoltage power supply. In the process, electrons pass through the wire and the power supply circuit to the negatively charged plates, where they again combine with positive ions and prevent the neutralizing of the negative charge on the grounded plates.

Dense clouds of charged air molecules, or ions, are diffused and accelerated away from the wire (toward the grounded plates) by electrostatic field and molecular forces. A dense cloud of air ions exists in the interelectrode space across the inlet to the electronic air cleaner. These ions attach to particulate and cause the particulate to be removed by the field. The disruption of the molecules in the process of creating the positive ions causes energy to be radiated. Some of this energy is in the visible light spectrum producing a visible corona around the wire.

The Collecting Section

While some collecting occurs in the ionizer of a two-stage electronic air cleaner, most takes place in the separate collecting section, or second stage. The collecting section is comprised of a series of flat metal plates set parallel to the airflow through the air cleaner. Their spacing is a design consideration that varies somewhat from air cleaner to air cleaner, but is usually about a quarter-inch. To make the collector work, a high voltage DC source is applied to every other plate. The alternate plates are grounded so that there is a high voltage difference between plates.

The following examines the collecting process with reference to just one set of two adjacent collecting plates. (This applies to a series of plates as well.) A uniform electric force field is produced between the two plates when a voltage is applied to them, creating a uniform distribution of electrons (negative charge) on the surface of one plate opposite an equal and uniformly distributed deiciency of electrons (positive charge) on the other. The voltage gradient is uniform throughout this field.

A single, positively charged particle entering such a field is acted upon by a force, the sum of all the attracting and repelling forces due to the interaction of the uniformly distributed charges on the plates and the charge on the particle itself. These forces accelerate the particle toward the negative (grounded) plate. Likewise, a negatively charged particle is forced toward the positive plate. As a design consideration, it is important to note that the amount of force on the particle depends on the amount of charge imparted on the particle in the ionizing section, the voltage applied to the cell plates, and the space between the plates. These relationships, along with the velocity of the airstream itself, account for significant differences in efficiencies between various types and brands of electronic air cleaners.

Because of the uniform characteristics, the amount of force on the particle is the same whether the particle is near the negative plate, positive plate or anywhere in between. If no other force is acting on the particle, it is accelerated (constant rate of increase in velocity) in the direction of the negative plate. The force on a small particle can be in excess of 1,000 times the force of gravity.

Other forces also act on this particle as it passes between the collecting plates in an air cleaner. Among them are the resistance of the airstream, the repelling and attracting forces between it and other particles, gravity, inertia and others. Any or all of these forces may affect the movement of the particle toward the collecting plates. Although the actual paths of particles in the collector vary considerably, the component of force (the electrostatic field force) toward the plates is great enough in relation to the downstream component to transport the particles along a nearly diagonal path to the collector plates.

The air cleaner designer uses this information to increase the effectiveness of the collecting section. He might lengthen the plates (in the direction of airflow) so that the particles have more time to migrate to them. He might increase the voltage, decrease the space between plates, decrease velocity or increase the charge on the particles by strengthening the electrostatic field in the charging section.

Other Air Cleaner Components

To maintain maximum efficiency, the air entering the cleaner must be equally distributed across the ionizer and collecting cell. This is accomplished with pre and afterfilters. The prefilter diffuses the air across the ionizer as it enters the air cleaner. It traps larger particles that could short out the active components and allows the precipitator to collect the small to submicron particles to which it is best suited. The afterfilter also aids in equalizing air distribution.

Measuring Efficiency

Finding an accurate test procedure and evaluation method has occupied filter manufacturers for over 20 years. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) Technical Advisory Committee on Air Cleaning has been establishing test procedures since the early 1930's.

Lack of standardization has resulted in line after line of filtering products which are almost perfect according to the manufacturer's own ratings. From published efficiency ratings, it is often only possible to find differences among filters in the last 1/10 of 1%. In recent years, there has been a more realistic approach to advertised ratings of air cleaning devices due, in part, to the emergence of electronic air cleaners and other new filter products.

Ozone

Ozone is a pungent, colorless, toxic, unstable form of oxygen. Its chemical symbol is O3 It is formed in nature as well as by artificial means. It is usually produced by the discharge of electricity (lightning) in ordinary air or by subjecting air or oxygen to ultraviolet radiation. Normally, it is present in low concentrations wherever there is oxygen. The ozone layer in the stratosphere at an altitude of about 35 to 40 miles has concentrations of 10 to 20 parts of ozone per million (PPM) of air. Normal down drafts and other atmospheric disturbances bring some of this ozone down to the surface of the earth where concentrations seldom exceed a few parts per million.

Ozone generators are devices that produce ozone as a primary function. Electrostatic precipitators, copy machines and arc welders are devices that produce some ozone as a by-product of their intended function.
Ozone can be injurious to health when reaching certain levels. It can have undesirable physiological effects on the central nervous system, heart and vision. The predominant physiological effect is that of irritation to the lungs resulting in pulmonary edema. On the positive side, ozone acts as a deodorizing agent for objectionable odors. It readily oxidizes organic matter and has a variety of uses such as sterilization of water, bleaching and control of fungi in cold storage rooms.

Like many substances, ozone has advantages and disadvantages depending on its intended use and concentrations. Concentrations of ozone, as related to adverse health effects, influence allowable exposure time. High levels of ozone can be tolerated for a short period of time or low levels of ozone for a long period of time.

OSHA (Occupational Safety and Health Administration) has established 0. 1 parts per million (PPM) by volume of air, 0.2 Mg/M3, as the maximum allowable safe concentration of ozone for an 8 hour industrial exposure.

Ozone, being a form of oxygen, mixes with and decomposes in air. Decomposition is more rapid in higher humidity. The amount of ozone, therefore, that will be in the air depends upon the rate of generation versus the rate of decomposition. Another factor affecting the amount of ozone is the dilution of the air. The above statement applies only to an airtight room. The average building today completely exchanges the air 1 to 4 times an hour depending on the insulation, tightness of construction and make-up air systems.

Independent laboratory tests show that some air cleaner generate ozone at an average rate of 0.8 parts per 100 million (PPHM), or 0.008 parts per million (PPM) or less, a figure well below allowable concentrations.