Chemistry: electrical and wave energy – Processes and products – Electrostatic field or electrical discharge
Reexamination Certificate
2000-06-01
2001-12-25
Mayekar, Kishor (Department: 1741)
Chemistry: electrical and wave energy
Processes and products
Electrostatic field or electrical discharge
C422S186220, C204S571000, C204S671000
Reexamination Certificate
active
06332960
ABSTRACT:
FIELD OF INVENTION
This invention relates fluid treatment systems. In particular, this invention relates to a device and method for purifying a fluid through the application of electrostatic fields.
BACKGROUND OF THE INVENTION
Fluid purification systems are used in many different types of applications. Water purification techniques are widely used in both open and closed-loop water systems to reduce levels of contaminants and to maintain conditions suitable for habitation, for example washing and bathing, leisure activities such as swimming. Perhaps most important, such systems are used to create potable water from various water sources which may contain different kinds of organic and inorganic contaminants that are unsuitable for human consumption, or even dangerous.
Both open- and closed-loop water systems, such as aqueduct networks, water towers, ice machines and particularly hot water systems such as boilers, vapour humidifiers and the like, are prone to calcification, scale formation and contamination by many types of biological contaminants. The nature and extent of these problems varies depending upon the water chemistry and the type of water system. In many cases, a large portion of the cost of maintaining a water system is devoted to the elimination of minerals and contamination caused by microbiological pollutants such as bacteria, endotoxins, moulds, parasites, fungus and viruses.
The purification of large volumes of water by conventional techniques has conventionally been costly and problematic. Chemical treatments tend to have undesirable side effects, and can actually be harmful if precise conditions are not maintained. Mechanical filtration is probably the most common method of water purification, but it is substantially limited both in terms of the rate at which water can be purified and the useful life of the filter used in the system.
Reverse osmosis filtration is one of the most effective filtration techniques. In a typical reverse osmosis filtration system, water is forced through a semi-permeable membrane to extract pollutants and contaminants. Reverse osmosis systems provide an extremely effective level of filtration initially, but this tends to degrade quickly as the membrane deteriorates and becomes clogged with contaminant particles.
In water treatment systems the filter membrane is subject not only to clogging by fine particles, but also tends to become positively charged as electrons are shed into the passing water, and the charged membrane actually attracts and holds neutral particles such as calcium carbonate, exacerbating clogging of the membrane. Moreover, reverse osmosis filter membranes require continual replacement as a result of constant wear and tear from undesirable elements, for example some types of inorganic contaminants, such as calcium carbonate, which coalesce in water systems to form sharp, needle-like structures that pierce and erode the filter membrane. This significantly limits the life of the membrane and results in a slowly deteriorating output water quality and filtration rate.
Reverse osmosis filter membranes are so sensitive that in many environments, once the efficiency of the filter membrane drops by as little as 2% the membrane must be replaced. Thus, reverse osmosis filter membranes must be replaced on a regular basis, which is very costly.
It is known to treat and/or pre-treat fluids such as water with electrostatic fields, to eliminate biological pollutants and reduce calcification and scaling in water circulation systems. However, there has previously been no system capable of efficiently and effectively treating fluids such as water in large volumes, or for treating fluids such as water for prolonged intervals without the need for continuous maintenance and replacement of filter membranes.
It would accordingly be advantageous to provide a system capable of reducing or eliminating mineralization and biological contamination in fluid circulation and distribution systems. It would further be advantageous to provide a system which effectively pre-treats a fluid prior to filtration, to reduce the harmful effects of contaminants on the filter membrane and thus prolong the useful life of the membrane.
SUMMARY OF THE INVENTION
The present invention provides a device and method for the treatment of fluids using electrostatic fields generated by a high voltage electric current. The device of the invention can be built into new water systems or retrofitted to existing water systems, to reduce or eliminate calcification, scaling and microbiological contamination, and to pre-treat water so as to enhance the performance and durability of purification systems such as reverse osmosis filtration systems.
The invention accomplishes this by applying a high voltage DC current to a core electrode, generating an electrostatic field which traverses a dielectric sleeve surrounding the core electrode and charges the exterior surface of the dielectric sleeve. The charge remains on the dielectric sleeve until transferred to a contaminant particle entrained in the fluid, charging inorganic particles and, in the case of a biological contaminant such as bacteria, killing the organism. Fluid flowing through the device is agitated by a combination of spiral vane sections surrounding the dielectric sleeve and helical baffle sections lining the housing wall. Charged inorganic particles coalesce into spherical aggregates, rather than the sharp needle-like structures which form naturally in water systems, and can be filtered by techniques such as reverse osmosis without deteriorating the filter membrane. Moreover, the inorganic microspheres retain the charge imparted by the device and are thus repelled by a reverse osmosis filter membrane, facilitating removal of the contaminants from the filtration chamber.
In open- and closed-loop circulation and distribution systems such as cooling towers, ice machines, boilers and the like, the inorganic spheres resist adhesion to pipes and vessels. The system of the invention thus reduces or eliminates biological contaminants as well as both calcification and scaling.
The device and method of the invention are particularly suitable for the purification of water in both open- and closed-loop circulation and distribution systems, and for the pre-treatment of water in water filtration systems, such as reverse osmosis systems, to increase the efficiency and consistency of the filtration process and reduce maintenance and filter replacement costs.
The present invention thus provides device for purifying a fluid, comprising a housing having a fluid inlet and a fluid outlet spaced from the fluid inlet, an electrode core disposed within the housing for connection to a high voltage electrical power supply, a dielectric sleeve disposed about the electrode core, the dielectric sleeve having an exterior surface comprising at least one spiral vane section for agitating a fluid flowing through the housing, and at least one ground electrode disposed within the housing spaced from the dielectric sleeve, wherein a high voltage electric current applied to the core electrode generates an electrostatic field which traverses the dielectric sleeve and imparts a charge to contaminants entrained in the fluid.
The present invention further provides a method of purifying a fluid, comprising the steps of forcing the fluid through a housing containing a core electrode surrounded by a dielectric sleeve, and at least one ground electrode spaced from the dielectric sleeve, agitating a fluid flowing through the housing by at least one spiral vane section provided on an exterior surface of the dielectric sleeve, and applying a high voltage electric current to the core electrode, wherein the high voltage electric current generates an electrostatic field which traverses the dielectric sleeve and imparts a charge to contaminants entrained in the fluid.
In further aspects of the invention the ground electrode comprises a plurality of ground electrode rings surrounding the dielectric sleeve; the ground electrode rings are fixed in spaced relation with
Dimock Stratton Clarizio
Eisen Mark B.
Hydra-Static Systems Inc.
Mayekar Kishor
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