text:
|Publication number
|Publication type
|Application number
|Publication date
|May 21, 1996
|Filing date
|May 6, 1994
|Priority date
|May 6, 1994
|Fee status
|Publication number
|James L. Filson, Wesley R. Carrera, Ramesh R. Bhave
|Original Assignee
|Illinois Water Treatment, Inc.
|Export Citation
|BiBTeX, EndNote, RefMan
|Patent Citations (20), Non-Patent Citations (8), Referenced by (65), Classifications (33), Legal Events (9)
|External Links: USPTO, USPTO Assignment, Espacenet
1. Technical Field
This invention relates to novel apparatus and process for filtering ultra pure water. In one aspect, the invention relates to a separations process for providing particle-free ultra pure water for use in the electronics and semiconductor industries.
2. Background
High purity water is required for semiconductor device manufacturing. In semiconductor manufacturing, high purity water is used primarily for wafer rinsing. This rinsing process removes both contaminants inadvertently introduced to the wafer during the manufacturing process as well as chemicals intentionally introduced to the wafer for the purpose either of cleaning or of etching patterns into the semiconductor surface or the conductive or dielectric thin films grown or deposited on this surface as required to produce a semiconductor device.
These chemicals include, but are not limited to, hydrofluoric acid, ammonium fluoride, phosphoric acid, piranha solutions (the generic name used for mixtures of sulfuric acid and a strong oxidizer: usually hydrogen peroxide or ozone), and the two component solutions comprising the industry standard RCA cleaning method, i.e, the so-called SC-1 and SC-2 solutions. (W. Kern and D. A. Puotinen, RCA Review, Volume 31, pp. 187, 1970.)
SC-1 is a mixture of ammonium hydroxide, unstabilized hydrogen peroxide, and ultra pure water. SC-2 is a mixture of hydrochloric acid, unstabilized hydrogen peroxide, and ultra pure water. Ultra pure water rinses are also used to remove the solvents used for the removal of photoresists. Ultra pure water is the chemical used in the greatest quantity in semiconductor manufacturing, and extremely large quantities of ultra pure water are produced in modern semiconductor production facilities.
The greatest cause of yield loss in modern semiconductor manufacturing is particulate contamination. Particles interrupt the photolithographic patterns that define integrated circuit components and can cause open circuits in the conductive metal thin films that wire these circuits together. When attached to a semiconductor wafer, particles are extremely difficult to remove as they electrostatically bond to the wafer. Therefore, all of the fluids which contact the semiconductor wafer must be rigorously filtered to remove particles. This includes ultra pure water.
Preferred characteristics for an ultra pure water filter, in addition to excellent particle removal efficiency, include quick rinse up, no shedding of its materials of construction into the water stream, no contribution of ionic species, minimal introduction of TOC (Total Oxidizable Carbon or Total Organic Carbon) to the water stream, and ozone and hot ultra pure water (UPW) compatibility. Ozone compatibility is important because ozone enables the destruction of microbial matter without the introduction of additional chemical agents such as chlorine or hydrogen peroxide which are themselves considered contaminants in ultra pure water. Microbial matter, such as bacteria and viruses, is the primary source of TOC.
Ozone is produced by spark discharge from ultra pure oxygen and eventually decomposes into diatomic oxygen in ultra pure water. It therefore offers an extremely clean method of system sterilization. This ability of ozone to kill biological contaminants is especially critical for ultra pure water systems as bacteria and microorganisms can grow rapidly in the conditions commonly found in ultra pure water distribution loops.
The above-described characteristics are desirable for all of the various types of filters typically used in ultra pure water systems: microfilters, tangential-flow or cross-flow filters such as ultra filters, and RO (reverse-osmosis) membranes.
Ozone can be utilized in an ultra pure water system in various ways. It can be used for initial sterilization of a system after construction. It can be used periodically afterward for re-sterilization after system component replacement or maintenance, or it can be used continuously.
Hot ultra pure water (UPW) has become desirable for semiconductor wafer rinsing as the diffusive removal of chemicals from solids is accelerated by heat, the diffusion process being temperature dependent. Additionally, most substances (although not all) are more readily soluble in hot water than in cold. The superior cleansing properties of hot UPW are perceived to extend as well to the removal of particles from the wafer surfaces. Currently used ultrafilters are incompatible with hot UPW. (M. S. Homick, K. L. Fulford, and S. Browne, "Design and Performance of a Central Hot Ultrapure Water System", Proceedings of the 1992 Microcontamination Conference, pp. 753-763, 1992.) The ceramic membrane ultrafilter is unaffected by hot UPW with or without ozone injection.
The different components used in UPW (ultra pure water) systems all have different levels of compatibility with ozone and hot UPW. Most final filters used to produce ultra pure water are not compatible with ozone. Therefore, most conventional final filters used to produce ultra pure water today must be taken out, or "valved out," of the loop during ozone sterilization. These conventional filters typically are sterilized separately with hot UPW or chemical solutions. Addressing final filters separately during frantic plant shut-downs creates extra work, thus increasing the length and cost of the shut-down. In many cases, ozone sterilization of the service loop will take place without the final filters on line. This situation invites particulate contamination of the service loop. Alternatively, hot ultra pure water sterilization, which is ideal from the standpoint of cleanliness, requires significant extra effort and equipment during the filter sterilization, and hot UPW may also attack the materials of construction of these final filters. Commonly used chemical oxidizing agents, such as hydrogen peroxide, have undesirable drawbacks associated with contamination and rinse up problems.
A preferred filter would also be resistant to particle release because of pressure fluctuations. Filter design is an important factor in determining the particle shedding characteristics of ultrafilters in both normal and pulsed conditions. Many types of filters including ultrafilters will shed particles or pass trapped particles when the feed pressure pulsates. (Meltzler, T. H., "An Investigation of Membrane Cartridge Shedding: A Quantitative Comparison of Four Competitive Filters", Transcripts of Sixth Annual Semiconductor Pure Water Conference, pp. 221-239, Santa Clara, Calif., Jan. 15-16, 1987.)
Conventional processes for producing ultra pure water typically use dead-end filtration with polymeric membranes. For example, conventional ultrafilters (similar in design to RO membrane systems) are used to produce high purity water for electronics applications. Spiral wound membranes, another commonly employed technology, require low solids in the feed stream and have high pressure drops associated with the restrictive liquid flow paths through their extremely narrow channels. The fouling of polymeric ultrafilters is a problem as is the requirement to periodically clean these filters off line. (D. Sinha, "Pretreatment Process Considerations for the Semiconductor Industry", Ultrapure Water 7(6), pp. 21-30 (1990).)
These and other known processes for producing ultra pure water for the electronics or semiconductor manufacturing applications, as represented in the following.
U.S. Pat. No. 5,292,439, assigned to Mitsubishi Kasei of Japan, discloses a method for preparing ultra pure water for use in electronics industries. The patent discloses that the water quality of ultra pure water is largely affected by impurities eluted from the materials constituting the purification apparatus. (Col. 1, bottom). An improved ion exchange process is provided to overcome the problems of the impurities eluted from the materials constituting the purification apparatus.
U.S. Pat. No. 5,259,972, assigned to Nippon Rensui and Mitsubishi Denki of Japan, discloses apparatus and method for purifying water for use in the electronics industry. The patent discloses that it is known to combine an ultrafilter membrane with ion exchange, ultraviolet (UV) sterilizers, cartridge filters, reverse osmosis (RO) and other components to produce ultra pure water. (Col. 1, line 18).
U.S. Pat. No. 5,160,429, assigned to Tadahiro Ohmi of Japan, discloses supplying ultra pure water for the electronic industry. The patent shows the use of ultrafiltration units 108 and 109.
U.S. Pat. No. 5,128,043 discloses apparatus and method for purifying water for use in the electronic industry. The patent discloses using an electric field. A specific object is to remove particles. Another object is to provide a method and apparatus not affected by ozone. A membrane filter 4 removes particulates. A final filter 12 is sized at 0.2 microns.
U.S. Pat. No. 5,124,033, assigned to Shinko Pantec of Japan, discloses an ultra pure water producing system for the semiconductor manufacturing process. Metallic ions and particulates are removed. An ultrafilter 39 is disclosed. The patent discloses that when water comes in contact with the materials of the devices and pipings, materials such as silica are leached out.
U.S. Pat. No. 5,073,268, assigned to Ebara Corp. of Japan, discloses a process for purifying water or ultra pure water for use in the electronics industry. An ultrafilter unit 22 is disclosed.
U.S. Pat. No. 5,061,374, assigned to Micron Technology of Boise, Idaho, discloses an ultra pure water system employing a second train which reduces particulate in the manufacture of integrated chips (IC's). The patent discloses ozone and membrane filters and reduces particulate in the water to a level of less than 30 counts per milliliter sizes 0.1 micron to 1 micron. (Col. 1, lines 48-50.)
U.S. Pat. No. 5,024,766 discloses water purification which reduces particulate in semiconductor manufacturing. The patent discloses ozone and submicron filter 20. Polymeric membrane filters marketed as Fluorodyne are disclosed at the top of Col. 9.
U.S. Pat. No. 4,879,041, assigned to Hitachi of Japan, discloses a process for producing ultra pure water for semiconductor manufacturing. The patent discloses ozone and membrane filters.
U.S. Pat. No. 4,863,608, assigned to Nomura Micro Science of Japan, discloses a process for producing ultra pure water for integrated circuits manufacturing. The patent discloses ultrafiltration and microfiltration.
There are many costly problems and drawbacks associated with the utilization of conventional loop or final filters in the conventional or prior art processes or methods for producing ultra pure water. One problem involves using ozone sterilization and/or high temperatures. If ozone is present, none of the conventional polymeric membranes are resistant with the exception of polytetrafluoroethylene (PTFE). If high temperature operation is required, organic extractables and short membrane life become problems for many polymeric membranes. Ozone can cause the oxidation and therefore growth of a polymeric filter's pore size resulting in lower particle retention levels with increasing exposure to ozone.
Accordingly, a drawback of conventional processes is the failure of the filter media surfaces or opening of the filter pores because of oxidation of non-resistant organic materials in the presence of strong oxidizing agents such as ozone.
Another drawback is the failure of welded polymer seams along the filter pleat.
A further drawback is the requirement of high flux or throughput for economic viability.
Another drawback is that ozone-resistant organic materials suffer from low flux.
The conventional methods utilize an organic copolymer membrane. Therefore, another drawback in dealing with such materials is that the oxidizing environment will degrade or produce organic impurities which raise TOC levels.
It is also a drawback of conventional methods in the requirement for a separate sterilizing agent because of non-compatibility with ozone, which is the current sterilizing agent of choice in the electronics industry.
Therefore, it is an object of the present invention to provide a stable, high flux ultrafiltration membrane for filtering ultra pure water.
It is another object of the present invention to provide a process for filtering particles from ultra pure water for use in electronics manufacturing.
It is a further object of the present invention to provide a process for filtering ultra pure water through an ultrafilter in hot, ozonated high purity water with no detectable metal extractables.
It is still a further object of the present invention to provide a process for filtering ultra pure water through a filter which passes toxicology tests to provide for use in food and pharmaceutical applications.
It is still a further object of the present invention to provide a process for filtering ultra pure water through a filter with no particle shedding.
It is still a further object of the present invention to provide a process for filtering ultra pure water through a filter which provides long membrane life and an economical and compact design.
It is still a further object of the present invention to provide a process for filtering ultra pure water through a filter providing a metal oxide membrane on a ceramic support which is able to withstand prolonged contact with ozone and/or high temperatures.
It is another object of the present invention to provide a process for filtering ultra pure water through a filter providing a metal oxide membrane on a ceramic support which does not alter ultra pure water properties, e.g., without leaching ions into the ultra pure water.
It is another object of the present invention to provide a process for filtering ultra pure water through a filter providing a metal oxide membrane on a ceramic support which maintains acceptable ultra purity filtration without leaching ions into the ultra pure water produced over high recoveries per pass, which result in longer times of water contact with the filter.
It is a further object of the present invention to provide a process for filtering ultra pure water through a filter which can be maintained and returned to operable condition by sterilizing with ozone or cleaning with steam, acid, and/or basic solutions.
A further object of the present invention is to provide a process for filtering ultra pure water through a filter which is integrity testable and bacteria and pyrogen retentive while providing acceptable flux and permeability, i.e., flux per unit transmembrane pressure, over a wide range of operating conditions.
It is yet another object of the present invention to provide a membrane filter which is insensitive to sudden process upsets such as high pressure pulses or temperature or both.
Another further object of the present invention is to provide a filter which can be back-pulsed with clean water flux to dislodge and remove contaminated trapped by the membrane layer.
These and other objects of the present invention will be described in the detailed description of the invention which follows. These and other objects of the present invention will become apparent to those skilled in the art from a careful review of the detailed description and from reference to the figures of the drawings.
The present invention provides for filtration of particle contaminants from ultra pure water by passing through a metal oxide membrane on ceramic support. In one aspect, the process of the present invention filters ultra pure water by passing a feed solution cross-flow through a multichannel sintered monolithic metal oxide membrane on ceramic support to form a permeate of particle-free ultra pure water. The sintered metal oxide membrane nominal pore size is in the range of about 50 to 500 Angstroms, preferably less than about 200 Angstroms.
In one aspect, the present invention includes providing cross-flow particle filtration, using multichannel monolithic ceramic membranes, at about 50-200 Angstroms pore sizes, in a total chemical process system including ozonation sterilization of the ceramic particle filter and the ability to operate continuously at elevated temperatures, e.g., above about 90� C. in water purification applications for electronics manufacturing.
FIG. 1 is a process schematic diagram of a system for generating ultra pure water as used in the "prior art."
FIG. 2 is a process schematic diagram of a system for filtering ultra pure water in accordance with the present invention.
FIG. 3 shows a schematic representation of a multichannel monolithic cross-flow membrane on ceramic support in accordance with the present invention and includes a detailed view of a section of the membrane on ceramic support.
FIG. 4 is a process schematic diagram of a experimental testing system for comparing the prior art with ultra pure water filtration in accordance with the present invention.
The present invention includes removing particles from high purity water for use in electronics applications using multichannel monolithic cross-flow ceramic membranes. It has been found through empirical testing that the advantages of using multichannel monolithic cross-flow 200 Å ceramic membranes in this filtration include an ability to run hot and to put ozone in the ceramic membrane filter for particle purification purposes. An unexpected result was observed in complete particle rejection together with no leaching of the membrane element.
The ceramic membrane ultrafilter's particle retentive characteristics of the present invention, because of its rigid construction, are unaffected by pressure pulses. This is a definite advantage.
Prior to the demonstration of this technology, it was believed that significant particle counts could be removed, but that the resulting product stream would contain ions formed from leaching out of aluminum.
It was found from work conducted by an independent analytical laboratory that the product water stream contained acceptable TOC, together with high particle removal. The independent analytical laboratory can detect aluminum at 0.007 parts per trillion, and none was observed at or above this detection limit.
The demonstration was unexpected and surprising in the result of no aluminum leaching because aluminum or alumina in contact with water will leach out aluminum ions at least in the parts per billion range. Such leaching is particularly expected in the case of ultra pure water. Although not certain, it may be that the mechanism operating here is attributable to the sintered nature of the membrane.
The novel filtration technology of the present invention is run with very high recoveries per pass such that water is in contact with the ceramic membrane over a high residence time. This aspect of the process makes the unexpected result of no leaching of the ceramic membrane elements even more surprising. The ceramic membrane ultrafilter's pore size was found to be unaffected by ozone independent of ozone concentration or length of exposure.
Conventional methods such as polymeric membrane ultrafiltration are less suitable because they cannot function in aggressive, higher temperature and extreme pH regimes. Polymeric ultrafiltration membranes are difficult to clean. The ceramic membrane ultrafilter disclosed in detail herein is far less susceptible to fouling by dissolved solids and can by cleaned dynamically during use without system shut-down by a technique know as backpulsing.
Polymeric ultrafiltration membranes provide only relatively low fluxes, i.e., low permeation rates per unit of filtering. Polymeric ultrafiltration membranes can not be back-pulsed at high pressures. Back-pulsing is the periodic application of counter pressure on the permeate side of the membrane element to push back a given permeate volume into the feed side of the membrane element to disrupt or destroy the gel layer or particle deposits on the membrane surface.
We have found empirically that the process of the present invention provides an efficient and effective process for filtering ultra pure water. The metal oxide membrane on ceramic support substantially removes particles from the water. We also have observed that the apparatus and process of the present invention provide advantages of filtering out contaminants while undesirable metal ions are not leached out into the ultra pure water product stream. Accordingly, we have developed practical and efficient filtration apparatus and method for filtering ultra pure water for use in electronics manufacturing and for cleaning the filter for repeated use. The apparatus and process of the present invention provide consistently high quality, particle-free ultra pure water.
The ultra pure water as produced in the apparatus and method of the present invention includes ultra pure water as referred to in electronics manufacturing as defined by the standards of Balazs Analytical Laboratory's Pure Water Specifications and Guidelines, 1993.
As used herein, the term "contaminants" include, either singly or in mixtures, ions, colloids, particles, and organic compounds, both dissolved or suspended. Also included in this term are materials which are impurities detected in the process fluid.
In one aspect of the process of the present invention, the membranes on ceramic support are chemically cleaned and can retain essential filtering characteristics even after ozone sterilization or aggressive, extreme pH cleaning in strongly acid or alkaline solutions.
Referring now to FIG. 1, a representative system for generating ultra pure water as used in the "prior art" will be described. Referring to FIG. 1, a typical ultrapure water production facility is shown incorporating common, conventional treatment technology. Municipal water in feed stream 1 enters multimedia filter 2. Multimedia filter 2 is designed to remove suspended solids present in the feed stream water supply. Water from multimedia filter 2 is passed in stream 4 to activated carbon filter 6 designed to remove oxidizing agents and organic compounds. Water from activated carbon filter 6 exits in stream 8. Acid in line 10 is introduced into stream 8 for pH control. An antiscalant in line 12 is added for scale control. Water is then passed to prefilter system 14. Prefilter system 14 is designed to remove suspended solids present in the feed water supply and to act as a polishing filter to the multimedia filter 2.
Water from prefilter system 14 is passed in line 16 to reverse osmosis booster pump 18, which increases feed water pressure by about 200-300 psig. Water at boosted pressure is passed through line 20 to reverse osmosis system 22. Reverse osmosis system 22 is designed to remove suspended and dissolved solids by more than about a 95% reduction. Reverse osmosis product water is removed in line 24 and fed to storage tank 26. By design, the percentage of reverse osmosis feed water, i.e., the feed to reverse osmosis system 22 which does not become reverse osmosis product water is termed the "concentrate" and exits reverse osmosis system 22 as waste through line 25 to drain 27.
Water from storage tank 26 in line 28 is supplied to repressurization pump 30, which increases water pressure by about 100-150 psig. Repressurized water in line 32 is fed to vacuum degasifier system 34. Vacuum degasifier 34 is designed to remove dissolved or entrained gasses through line 36 and vacuum pump 38. Water from vacuum degasifier 34 is passed in line 40 to enter repressurization pump 42, which increases water pressure by about 100-150 psig.
Repressurized water in line 44 is fed to ultraviolet system 46. Ultraviolet system 46 is designed to reduce the total amount of organic contaminants. Water from ultraviolet system 46 is fed in line 48 to primary mixed bed deionizer 50 which is designed to remove dissolved ions.
Water then is passed in line 52 to ultraviolet system 54 designed to reduce the total amount of bacteria or microorganisms. Water then is passed in line 56 to final polishing deionizer 58 which is designed to remove any ionic contamination not removed by primary deionizer 50.
Water from final polishing deionizer 58 is passed in line 60 to loop booster pump 62 which boosts water pressure by 100-150 psig. Boosted pressure water in line 64 enters ultrafilter prefilter 66. Water then is passed in line 68 to prior art ultrafilter 70 which is designed to remove suspended solids. The ultrafilter product water in line 72 is supplied to points of use. By design, the percentage of ultrafilter water which does not become ultrafilter product water is termed "reject," and exits the prior art ultrafiltration system 70 as waste through line 74 to drain 76.
In the prior art process, the ultrapure water containing contaminants is introduced into a polymeric membrane system in line 68. The ultrapure water containing contaminants is introduced into an element pressure vessel 70 containing the polymeric membrane (not shown). Water flows across the surface of the membrane cross-flow. The polymeric membrane uses an envelope design with three sealed sides and the fourth side attached to a product tube (not shown). This design renders the membrane system susceptible to irreversible damage caused by back pressure or sudden backpulses. Water passing through the membrane is termed flux, permeate, or product. Permeate flows from the membrane and is collected in the product tube and exits the pressure vessel 70 in line 74. Water, by design, not permeating through the membrane is termed concentrate, retentate, or waste. Waste exits the pressure vessel 70 in line 72 where it goes to drain or to some reuse program. This system is operated as a feed and bleed system. It has a maximum temperature limit of 50 degrees C., a pH range from 2-13, limited resistance to some oxidizing agents with no resistance to ozone, and limited resistance to back pressure/pulses.
Referring now to FIG. 2, the present invention provides particle filtration of water in line 68 fed to module 80 containing a ceramic element having a metal oxide membrane. Water in stream 82 exits module 80 and is supplied as particle-free ultra pure water to points of use. Clean water supply in line 84 is used to carry out the backpulsing mode described in detail hereinbelow. By design, the percentage of the feed water which does not become product water is termed "retentate" and exits through line 86 as waste and goes to drain 90.
The separation membrane housing or module includes an annular housing, preferably of stainless steel, which contains at least one longitudinal ceramic element mounted therein. As will be explained further hereinafter with respect to FIG. 3, the ceramic element includes a metal oxide membrane on ceramic support. Any number of ceramic elements can be contained in a module, up to 37 as used in accordance with the present invention.
The ultra pure water containing contaminants is introduced into the ceramic membrane system in line 68. The feed water enters the module housing 80 and flows across the surface of the membrane in a cross-flow pattern. The ceramic membrane utilizes a multi-channel element with the membrane sintered to a support matrix which is shown and described in more detail hereinbelow. The membrane of the present invention allows the membrane system to be back pulsed with clean water flux to dislodge and remove contamination trapped by the membrane gel layer. Water passing through the membrane is termed flux, permeate, or product. Permeate flows from the membrane and through the support matrix and is collected within the confines of the housing and exits in line 82. Water, by design, not permeating through the membrane is termed concentrate, retentate, or waste. Waste exits the pressure vessel 80 in line 86 and goes to drain 90 or to some reuse program. During the back pulse sequence of operation, permeate from line 82 is supplied to line 84 in order to dislodge and remove contamination trapped by the membrane gel layer and is rinsed from the element through line 86 where it goes to drain 90 or to a reuse program. The present invention has been structured and operated as a feed and bleed system.
As will be explained in further detail with respect to FIG. 3, a cross-flow or tangential flow filtration process is established. The feed stream enters the element at a feed side of the element. The feed stream minus settled contaminants moves across or parallel to the membrane of the ceramic element while removing permeate solution tangentially through the element. The permeate is transported away from the module 80 containing the ceramic membrane element via a permeate outlet and through permeate line 82 into a permeate collection tank. The permeate fed in line 82 is particle-free ultra pure water. Ultra pure water fed in line 82 then can be used in the electronics fabrication (FAB) manufacturing operations or processes.
Flowing in the retentate side of the module 80 is the concentrate where contaminants are retained. The retentate will flow from the retentate output side of the module into output line 86 and into a recycle reservoir for a batch mode process with total recycle. A continuous process termed feed and bleed method can be operated where a predetermined recovery rate is maintained.
The process is continued until a steady state is reached or a predetermined concentration of contaminants is achieved in the retentate, also expressed as per cent recovery. The recovery rate or per cent recovery is defined as the ratio of permeate obtained per unit volume of feed multiplied by 100 or as shown in the following equation.
% Recovery=(Permeate Rate/Feed Rate)�100
In any case, the filter then is cleaned. The filter may be renewed by flowing ozone, preferably, or acid or alkaline cleaning solutions, alternatively, through he ceramic element. The ozone or the acid or alkaline solution contacts the ceramic element membrane surface but does not have to pass across the membrane as permeate. The composition of the ceramic support and membrane layers can withstand such harsh cleaning without sacrificing its essential characteristics, which are high permeability to water, exceptionally good chemical resistance properties, and an ability to preserve the pore structure intact.
Referring now to FIG. 3, a schematic diagram is shown of a portion of the ceramic element 3 used in accordance with the process and apparatus of the present invention. Ceramic element 3 includes ceramic support 5 of alpha-alumina which has multiple channels 7 incorporated in monolithic support material. Channels 7 can be 3, 4, 6, or 7 mm in diameter and can be present in multiple number, such as the nineteen channel element depicted in FIG. 3. A one-channel element also can be provided as well as a thirty-seven channel element. A membrane layer 9 of metal oxide coating preferably is formed on the inside of axially oriented channels.
Ceramic support 5 is preferably an alpha-alumina, multi-layer support although other support materials such as iron oxide, titanium oxide, zirconium oxide, zeolite (alumina/silica oxide), and silicon oxide can be used. The alpha-alumina support is a multi-layer structure comprising one or more sublayers, e.g., such as a sublayer of 0.2 micrometers pore diameter preferably about an average of 20 micrometers thick. The membrane layer 9 is further supported on a second sublayer, e.g., of about 0.8 micrometers pore diameter of about an average of 40 micrometers thickness, on the other side of the first sublayer. This structure then is further supported on a porous support which has a pore diameter of about 10 to 15 micrometers and a thickness of about 1.5 to 2 mm. The above ranges are exemplary in nature and thinner membranes and supports can be used.
Membrane layer 9 is preferably made of a sintered zirconium oxide optionally with yttrium oxide as a stabilizer. Other metal oxide particles which can be employed as the membrane layer in the invention, either singly or in mixtures thereof, include sintered zirconia or alpha-alumina (alpha-alumina for applications requiring nominal pore sizes of the membrane of about 0.2 micron and above) or other sintered metal oxides which provide the characteristics required in the apparatus and process of the present invention and which are capable of withstanding aggressive and extreme pH of alkaline or acid or strong chemical oxidants such as ozone at elevated temperatures.
In one aspect, the apparatus and process of the present invention include using a ceramic support and sintered zirconium oxide membrane controlled to have nominal pore sizes of less than about 200 Angstroms (20 nanometers). By controlled nominal pore size is meant establishing an average pore size, e.g., such as about 200 Angstroms, including more than about 95% of the pore sizes within the range of about plus or minus 5% of the nominal pore size, e.g., such as plus or minus 10 Angstroms in the case of a 200 Angstroms nominal pore size. In one embodiment, the nominal pore size of the zirconium oxide membrane on the support of the present invention is about 200 Angstroms, thereby providing higher flux.
Raw materials for the outer coating of the membrane include zirconium oxide stabilized with yttrium oxide. These raw materials are mixed with water or alcohol and a suspending agent to form liquid suspensions called slips. The slips are deposited onto the support and are heated to drive off the liquid medium, to burn off the suspending agent, and to sinter the membrane.
Slip preparation from the yttrium oxide-stabilized zirconium oxide begins by mixing the ZrO2 powder with water and organic additives to form a homogeneous suspension. The organic additives, polyvinyl alcohol, and ethanol act as deflocculating agents and also help to adjust the rheological properties of the slip. They are evaporated or burned off later in the manufacturing process. The suspension then is diluted with water.
The slip prepared by the above method next is allowed to flow over the support where it is deposited and dried. The newly-formed layer then is subjected to a heat treatment in an oxidizing atmosphere which removes excess water and alcohol. The heat treatment also oxidizes the organic additives and sinters the ZrO2 particles, thereby fusing them to each other and to the support. Maximum temperatures during the heat treatment vary with the pore diameter desired for the final product, but preferably the temperatures reach at least 500� C. to ensure all organic additives have been oxidized.
The present invention includes passing a feed 11 of ultra pure water 13 containing particles 15 through the ceramic element 3 in a cross-flow or tangential flow over membrane layer 9. By cross-flow or tangential flow, feed 11 can be channeled essentially perpendicular to the flow of the permeate 17 through support 5 and separated from retentate 19 as shown in FIG. 3.
In one embodiment, a specific membrane on support for the apparatus and process of the present invention can be provided by United States Filter Corporation/Membralox Division having an office at 181 Thorn Hill Road in Warrendale, Pa. The U. S. Filter membrane is referred to as a zirconia ultrafilter.
The separation process involves complete removal from permeate 17 of particles, colloidal and suspended, including bacterial debris, if any.
The following actual example illustrates the membrane and method of the present invention as providing superior results over prior art processes.
The objective of this actual example was to determine whether or not there was any compatibility of an alumina ceramic membrane with ultra pure water. A pilot scale unit operation depicted in the schematic of FIG. 4 was carried out incorporating a polysulfone prior art ultrafiltration system and a 200 Angstrom zirconium oxide sintered multichannel membrane on alphaalumina support sealed into a separation membrane module. FIG. 4 is a process schematic diagram of the experimental testing system comparing the prior art with a process for filtering ultra pure water (UPW) in accordance with the present invention. Ambient UPW was supplied to the element housing through valves. Feed water data were gathered from a pressure gauge, and a sample valve supplied water to be tested to on-line analytical equipment. Feed water entered the housing through the inlet port. Air was vented from the housing through a vent port and valve. Permeate exited the housing through an outlet port. A valve supplied water to be tested to the on line analytical equipment. Permeate pressure was indicated by pressure gauge. A valve was utilized for permeate isolation with a flow meter for flow totals and drain line taking all permeate to a waste drain. Retentate exited the housing through an outlet port. A valve was utilized for the purpose of fast flush to drain. Retentate pressure was indicated by pressure gauge. A valve for retentate isolation was provided with a flow meter for flow totals and a drain line taking all of the retentate to a waste drain.
For hot UPW, ambient UPW was supplied to the heat exchanger. From the heat exchanger, hot UPW was supplied to the element housing.
For ozonated UPW, hot or ambient valves were opened allowing water to pass through the eductor drawing in ozone.
Sampling of the ultra pure water and the analysis work was performed by an independent laboratory (Balazs Analytical Laboratories located in Austin, Tex. and Sunnyvale, Calif.) to show that the filter was not adding any measurable contamination. Referring now to FIG. 4, water exiting ultrafilter prefilter 66 in line 68 was fed (1) in stream 90 supplied to heat exchanger 92 and (2) in stream 91 to valve 98 or to polysulfone prior art ultrafiltration system 70.
Heat exchanger 92 increased feed water temperature by about 50-150 degrees F. As needed, hot ultrapure water was fed from heat exchanger 92 through line 94 to valve 96 and to lines 95 each containing the same water characterization. Valves 99 and 100 were isolation valves located between lines 95 and were used to provide proper flow conditions. Valve 102 on line 95 supplied ultrapure water, either hot from line 95 or ambient from line 91, to ceramic membrane module 110 through housing inlet port 108. Pressure indicator 104 measured feed water pressure. Sample valve 106 supplied feed water samples in line 107 to on-line analytical equipment 112. In the experimental mode, housing 110 had port 114 used as a vent port to vent air or water from the test system through valve 115.
Housing port 116 was used as a product port supplying product water through line 118 to valve 120. Valve 120 supplied product water samples to on-line analytical equipment 112 through line 121. Water in line 118 is passed to pressure indicator 122 for providing product water pressure data, then through valve 124 as an isolation valve on line 118, and finally through product water flow meter 126 before passing in line 118 to drain 200.
Housing port 130 supplied water in line 132 through valve 34 as a fast flush through line 135 to drain 200. Pressure indicator 136 provided retentate pressure of line 132. Water in line 132 was passed through isolation valve 138. Water from valve 138 was passed through retentate flow meter 140 and line 39 before going to drain 200.
Ozone was added to the test system through line 150 into eductor 152. Valves 154 and 156 were opened for ozone addition and valves 99 and 100 were closed.
When steady state was established in pressure, linear velocity of solution through the feed channels, and temperature, the permeate valve in the membrane module was opened, and a flux was established corresponding to a transmembrane pressure differential of approximately 5 bar. Operating parameters were logged twice daily over a four week period. The permeate valve then was closed. Virgin membrane flux and permeability were calculated and served as a baseline for determining membrane regenerability after cleaning, should fouling occur. Ambient temperature deionized water was added to the feed tank until the final desired operating volume was attained. The valves then were configured to enable circulation of the water through the feed side of the process. The permeate valve was opened, and the water allowed to permeate the membrane at steady state conditions with the permeate solution being returned to the feed tank. Operations were continued for a period of four weeks to identify any long term membrane leaching or shedding.
After cleaning with ozone, clean water flux of the cleaned membrane was calculated and compared to the virgin membrane flux. Hydrogen peroxide was used as the primary cleaning agent during the study, taking 30% and blending it down to 10%.
Metal ions in the permeate were found to be almost negligible.
A 200 Angstrom sintered zirconia ultrafiltration membrane on alpha alumina support was observed to filter at a level as reported in the Tables. Flux values with the 200 Angstroms zirconia membrane were observed to be acceptable. Particles were 100% retained at lower transmembrane pressures.
Operating parameters to determine whether fouling was taking place were recorded. Also recorded were data to show the rinse-up characteristics of the filter. During the four week study, the element was not back pulsed, and no fouling of the element was reported as developing. However, daily fast flushes were run where the waste valve was opened to increase the velocity across the membrane surface. The same method was utilized for the polymeric membrane system.
It is important to note that the membrane element and housing were shipped separately to prevent shipping damage and the element installed into the housing at the test site in a non-clean room environment. The assembled module was then placed within the test system. The test system (piping and element) then underwent a cleaning for particles and biomatter with a 10% hydrogen peroxide (30% MB Grade H2 O2 blended with ultra pure water) solution before going on line.
Ceramic element characteristics are shown in Table I.
TABLE I______________________________________ELEMENT CHARACTERISTICS______________________________________Model No.: P19-40 with 0.2 m2 of surface areaMembrane: Zirconia 200 Å pore sizeMembrane Support: Alpha alumina matrix (12 to 15 micrometers)Permeability: 400 L/hour per m2 per bar Δp (evaluated model P19-40 with 0.2 m2 of membrane surface area yielding 80 L/hr per bar nΔp)pH Capabilities: Alpha alumina: 0-14 Zirconia: 0-14Operating Temp.: 215� C. Limited only by gasket materialsOperating Pressure: 120 psi standard modules, higher pressure modules availableBurst pressure: Limited by the maximum housing pressure______________________________________
For the purpose of challenging the ceramic element under normal operating conditions over a four week experimental period, the element was set up to operate at conditions close to normal design parameters (model P19-40 with 0.2 m2 of surface area yielding at least 80 L/hr per bar Δp). Throughout the course of this actual example, the ceramic element gave no indications of degradation to mechanical, structural, or final product water quality. The performance held constant with no significant decline in permeation rate.
Inlet pressure to the membrane averaged 94 psi during the study with a minimum pressure of 90 psi and a maximum of 100 psi being recorded.
Trans-membrane Δp averaged 72 psi (about 5 bar) during the study with a minimum differential pressure of 68 psi and a maximum of 77 psi being recorded.
The recorded product flow rate averaged 7.6 L/min. during the example with a minimum flow rate of 7.6 L/min. and a maximum of 8.0 L/min. It should be noted that the sample port for the on-line analytical instruments was upstream from the product flow meter and therefore not represented in the product flow data. The average flow rate to the analytical instruments during this example was recorded to be 271 mL/min.
Waste flow rate averaged 1465 mL/min. during the example with a minimum flow rate of 1420 mL/min. and a maximum of 1600 mL/min. being recorded.
The recoveries per pass rate averaged 81% with a minimum of 80% and a maximum of 82%. The recoveries per pass rate calculations take the analytical instrument flow rate into account.
Particles (On-line): Particle Measuring Systems (PMS--Boulder, Colo., USA): Micro LPS-PB with LVP-0.5 measuring cells. At start up, the PMS indicated 135 particles/L at 0.5 pm and within 8 hours had rinsed to 10 particles/L at 0.5 μm. The data indicated an average count of 3 particles/L at 0.5 μm during the example. During this example, the analyzer was set to a sampling volume of 0.2 L. At this setting and with this sensitive instrument, a comparison of very low particulate ultra pure water systems is not possible. On-line particle counters would provide higher sensitivity.
Total Oxidizable Carbon (TOC) On-line (Anatel Corp.-Boulder, Colo. USA): Model A-100P. Anatel rates this instrument as having a dynamic range down to 10 ppb. However, experience with the meter shows it to be equivalent to the more sensitive Model A-100P SE in side by side comparison. The Model SE was calibrated to a 1 ppb standard before this example was started. The TOC at start up was recorded (by the A-100P) to be 4.9 ppb and within 4 hours had rinsed to 2.1 ppb. The data indicated an average TOC level of 0.65 ppb during the example. For comparison, the polysulfone filter initially had a TOC reading of 1600 ppb.
Resistivity: Thornton Model 822-A01 controller with model 211 cell. This system is not National Institute of Science and Technology (NIST) traceable. Therefore, it was only used to provide trending data. The initial resistivity reading was 4.5 M-ohm/cm lower than the final reading. Within 4 hours, the reading had increased to 1.2 M-ohm/cm lower than final reading. Within 16 hours, resistivity had rinsed to 0.5 M-ohm/cm lower than final. The final resistivity was reached within four days. The final resistivity was approximately 18.2 megohm/cm because of the lack of charged species found in the product water.
The third party tests for contamination were performed as follows:
TRACE METALS: Balazs method using SCIEX/Perkin-Elmer Inductively Coupled Plasma/Mass Spectrometry (ICPRllS) equipment modified for lower detection limits. This test used the low level boron option. The first contamination concern was zirconium, yttrium, or aluminum leaching because of the construction material of the membrane. Therefore, more trace metal data were taken than any other type of off-line analytical data.
TOC (Off-line): Balazs procedures using O.I. Instrument equipment. The sampling procedure exposes the sample to air which allows for probable contamination at this low TOC level. Higher TOC data were obtained at other times, but are not reported here.
PARTICLES by Scanning Electron Microscope (SEM): Balazs Method using Cambridge Scientific Model. Data from SEM can be highly dependent on the sample volume. Data reported is from samples taken with the most similar sampling volumes. Because of concerns about analytical filter integrity, SEM data was not taken for the hot ultra pure water tests.
The precision information supplied by Balazs is based on the sample volume passed through the analytical filter, the number of particles counted and the fraction of the analytical filter examined. The actual precision of the analysis will be worse than reported. Random factors including the number of particles added to the filter during sampling and the number of particles on the filter (as supplied) cannot be accounted for in the precision calculations.
BACTERIA by culturing : Balazs modified ASTM method with a 1 L sample size using Millipore Sterile Sampling Valves. Bacteria data are reported in colony forming unit (CFU) per 100 mL.
SILICA: Balazs molybdate complexing methods. Non-dissolved or colloidal silica is calculated by subtracting the dissolved (reactive) silica from the total silica.
IONS: Balazs methods using Dionex ion chromatography equipment. The lower detection limit used for the ultra pure water guidelines was not available during this example.
The Balazs guidelines do not specify concentrations for all metals tested. All shaded data in the trace metal portion of the table are for specified metals.
Other trace metal data given here are current ICP/MS detection limits except as noted below. Several complete sets of analytical tests were performed at both room and 54� C. temperature. Boron analysis is by low detection limit method. A 0.01 ppb detection limit for iron was available but not used for this testing.
Tables II and III present a compilation of results from this actual example.
Table II provides analytical data relating to trace metals measured in the product water stream of the present invention.
TABLE II______________________________________TRACE METAL ANALYSIS DetectionMetal Limit ppb Measured ppb______________________________________Aluminum (Al) 0.007 --Barium 0.002 --Boron (B) 0.3 0.25Chromium (Cr) 0.008 --Copper(Cu) 0.005 --Iron (Fe) 0.01 <0.1Lithium (Li) 0.004 --Magnesium (Mg) 0.002 0.004Manganese (Mg) 0.004 --Nickel (Ni) 0.005 --Sodium (Na) 0.007 --Strontium (Sr) 0.002 --Yttrium (y) 0.005 --Zinc (Zn) 0.008 --Zirconium (Zr) 0.005 --______________________________________
Although there was an initial concern based on the best available engineering regarding some trace metals because of the production method of the present invention, Table II shows that aluminum, yttrium, and zirconium were not found above the detection limits of the analytical equipment. Based on the experience and the professional opinion of the independent laboratory conducting the test, the contamination which was detected above the detection limits was atmospheric contamination picked up by the water during the time of sample collection.
Table III provides analytical data comparing items measured in the product water stream of the present invention to established Pure Water Guidelines.
TABLE III______________________________________ULTRA PURE WATER CHARACTERISTICS Balazs 1993 UPW Membralox� Guidelines (11) 0.02 μm______________________________________Resistivity 18.2 n/aM ohm/cm @ 25� C.TOC ppbOff line <10.0 5.0On line <1.0 0.7Particles/L (SEM 0.1 μm)0.10-0.20 μm <200 137 � 560.20-0.50 μm <100 84 � 410.50-1.00 μm <1 39 � 22>1.00 μm <1 36 � 23Volume Sampled 3168Particles/L (on line)0.05-0.1 μm <100 n/a0.1-0.20 μm <50 n/a0.2-0.30 μm <20 n/a0.3-0.50 μm <10 0.7 avg.>0.50 μm <1 0.11 avg.Bacteria (by culture)cfu/100 mL <0.1 <0.1Silica/ppbDissolved <0.2 0.2Non-Dissolved <0.5 0.5Total <0.5 0.7Ions/ppb (by Ion Chroma-tography)CationsLithium Li+ <0.05Sodium Na+ <0.01 <0.05Ammonium NH4 + <0.06 <0.1Potassium K.sup. + <0.02 <0.1AnionsFluoride F- <0.1 <2.0Chloride Cl- <0.02 <0.05Bromide Br- <0.02 <0.1Nitrate NO3 - <0.02 <0.1Nitrite NO2 - <0.02 <0.05Phosphate HPO4.sup.═ <0.02 <0.1Sulfate SO4.sup.═ <0.05 <0.1______________________________________
The tests were performed utilizing the best available technology during the time the study was conducted. The following provides a brief description of those findings. Resistivity was not reported because the instrument utilized to collect this data was not NIST traceable and was used only for reference. During this actual example, no drop in water quality was detected. TOC off line detected no drop in water quality. TOC on line noted an improvement in the initial TOC levels when compared to the initial TOC levels of the polymeric membrane system. No drop in water quality was detected. As to Particles by SEM, the independent laboratory reported excellent results. It is their opinion, based on experience, that the results would even improve had higher sample volumes run through the SEM filters to provide better resolution. As to Particles by On Line Detection, the independent laboratory reported excellent results. During the actual example, no drop in water quality was detected. As to Bacteria by Culture and Ions by Ion Chromatography, the independent laboratory reported excellent results. During the actual example, no drop in water quality was detected.
Tests were performed utilizing the best available technology during the time the actual example was conducted.
The data presented in the Tables show very little, if any, difference between the ceramic filter and the polysulfone filter. The dissimilarities shown are not greater than the uncertainty of the test measurements associated with the analyses. The variability between particle counts by SEM for the ceramic filter and the polysulfone fit into that category. In fact, the contrast between the SEM counts for the two filters and the Balazs specification also fit into that category.
The ceramic filter did not show any sign of degradation or any other operational problems during this test. The total permeate flow was slightly higher than specification (7.8 L/min. total flow at 72 psi compared to 6.4 L/min. specified).
In the area of filter cleanliness, the only significant difference between filters is that the initial TOC for the ceramic filter element was significantly lower than the initial TOC for the polysulfone filter element. Rinse-up characteristics of the ceramic filter were quite positive compared to experience with other filters.
The distinction between the silica data for the two filters was small. The data also were close to the detection limits such that no difference exists in silica retention.
The ceramic filter tested appeared suitable for use in semiconductor ultra pure water systems in respect to cleanliness at both room and elevated ultra pure water temperatures. The ceramic filter did not contribute measurably more particles than the conventional polysulfone filter. It also did not plug or foul when operated in the same way as the polysulfone membrane.
A 200 Å multichannel monolithic cross-flow 1P1940 element through a test protocol which included on-line TOC analysis, particle count, resistivity measurements, and trace metal analysis performed after two days of running and then after five days of operation at Balazs laboratories to determine extractables from the ceramic elements.
The system was operated at 83% recoveries per pass and at very low cross-flow velocities since the water has been through an RO filter and then deionized before entering the multichannel monolithic cross-flow system. The industrial interest in this application relates to the need to replace polymeric 10,000 MW ultrafiltration systems with a membrane that can tolerate both ozone and high temperature if necessary.
The module for this application extended the rinse up of the module at startup. It took about a week to rinse out the TOC components from Viton gaskets, and particle counts were slow to reach zero.
It is recommended that the housings and gaskets should be rinsed before installing them into the housing in a clean room environment. It is recommended then to cover or bag the housings with particle-free bags and should realize a one day rinse up to operation.
The current representative operational parameters for the system are as follows:
______________________________________Pressure in: 90 psigPressure out: 89 psigPermeate back pressure: 25 psigTemperature: 80� F.Feed flow: 2.51 gpmPermeate flow: 2.08 gpmConcentrate flow: 0.43 gpmFast Flush frequency: 2.5 gpm/every 8 hrs. for 5 min.______________________________________
The Table II trace metal analysis sheets show some sodium leakage from their IX columns. Boron was primarily coming from the feed water and was in line with the existing water system results, and Magnesium was unexplained. Particle counts were zero, and the TOC on-line analyzer indicated that the permeate from the ceramic membrane was identical to the existing water system quality.
The need for extremely clean water in the production or manufacturing of electronics components or semiconductors has always been an important issue, and it will continue to be an important issue far into the foreseeable future. Each ultra pure water facility in operation today must be scrutinized to identify areas of improvement in system operation and quality that can be made now so that the stringent manufacturing needs of tomorrow can be met. The present invention is a result of current developments underway in researching improvements in the filtration of ultra pure water and documenting comparisons between different filter media.
Thus it can be seen that the invention accomplishes all of its objectives.
Although the invention has been illustrated by the preceding actual examples, it is not to be construed as being limited to the materials employed therein.
Whereas particular embodiments of the invention have been described hereinabove, for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details may be made without departing from the invention as defined in the appended claims.
The apparatus and process of the present invention are not limited to the descriptions of specific embodiments presented hereinabove, but rather the apparatus and process of the present invention should be viewed in terms of the claims that follow and equivalents thereof. Further, while the invention has been described in conjunction with several such specific embodiments, it is to be understood that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing detailed descriptions. Accordingly, this invention is intended to embrace all such alternatives, modifications, and variations which fall within the spirit and scope of the appended claims.
|Cited Patent
|Filing date
|Publication date
|Sep 5, 1975
|Mar 29, 1977
|Systems Engineering & Manufacturing Corporation
|Wastewater treatment
|Nov 20, 1975
|Jan 17, 1978
|E. I. Du Pont De Nemours And Company
|Ultrafiltration device
|Feb 10, 1984
|Sep 9, 1986
|Sterimatics Company Limited Partnership
|Process and system for producing sterile water and sterile aqueous solutions
|Feb 7, 1985
|Oct 6, 1987
|Hitachi, Ltd.
|Apparatus for producing ultra-pure water by ion exchange resin
|Mar 9, 1988
|Sep 5, 1989
|Nomura Micro Science Co., Ltd.
|Photocatalytic treatment of water for the preparation of ultra pure water
|Mar 24, 1988
|Nov 7, 1989
|Hitachi, Ltd.
|Process for producing ultra-pure water and process for using said ultra-pure water
|Aug 6, 1990
|Apr 9, 1991
|Wisconsin Alumni Research Foundation
|Metal oxide porous ceramic membranes with small pore sizes
|Nov 9, 1988
|Jun 18, 1991
|Shahzad Mahmud
|Point of use deionized water purification unit
|May 16, 1990
|Jul 9, 1991
|Massachusetts Institute Of Technology
|Process for the preparation of a binary membrane top layer
|Dec 18, 1989
|Oct 29, 1991
|Micron Technology, Inc.
|Reverse osmosis as final filter in ultrapure deionized water system
|Dec 11, 1990
|Dec 17, 1991
|Ebara Corporation
|Process and system for purifying pure water or ultrapure water
|Jul 3, 1990
|Apr 14, 1992
|Aluminum Company Of America
|Pyrogens separations by ceramic ultrafiltration
|Apr 30, 1990
|Jun 23, 1992
|Shinko Pantec Co., Ltd.
|Ultrapure water producing system
|Feb 13, 1991
|Jul 7, 1992
|Wildermuth Glen W
|Method and apparatus for purifying liquids
|Jun 29, 1989
|Nov 3, 1992
|Tadahiro Ohmi
|Piping system for supplying ultra-pure water
|Apr 25, 1991
|Sep 7, 1993
|U.S. Filter/Illinois Water Treatment, Inc.
|Bacteria removal by ceramic microfiltration
|May 13, 1992
|Oct 5, 1993
|Studiengesellschaft Kohle Mbh
|Procedure for the preparation of microporous ceramic membranes for the separation of gas and liquid mixtures
|Jul 30, 1991
|Nov 9, 1993
|Nippon Rensui Company
|Apparatus and method for purifying water
|Oct 8, 1991
|Dec 7, 1993
|Anderson Marc A
|Microprobes aluminosilicate ceramic membranes
|Nov 22, 1991
|Mar 8, 1994
|Mitsubishi Kasei Corporation
|Method for preparing ultrapure water
|Collentro, "Filtration: An Overview of Present and Future UF Technologies for Semiconductor, Pharmaceutical, and Power Applications," Ultrapure Water, pp. 20-31, Sep. 1993.
|Collentro, Filtration: An Overview of Present and Future UF Technologies for Semiconductor, Pharmaceutical, and Power Applications, Ultrapure Water, pp. 20 31, Sep. 1993.
|Lloyd and Bentley, "Evaluating Point-Of-Use Membrane Filters Under Pulsed-Flow Conditions," Microcontamination, pp. 37 et seq., Apr. 1992.
|Lloyd and Bentley, Evaluating Point Of Use Membrane Filters Under Pulsed Flow Conditions, Microcontamination, pp. 37 et seq., Apr. 1992.
|Pate, "Filter Research: DI Water Ultrafilters Filtration Efficiency and Ozone Compatibility Study," Ultrapure Water, pp. 35-41, Sep. 1991.
|Pate, "Filtration: Ozone Compatibility Study of DI Water Filters," Ultrapure Water, pp. 42-50, Sep. 1990.
|Pate, Filter Research: DI Water Ultrafilters Filtration Efficiency and Ozone Compatibility Study, Ultrapure Water, pp. 35 41, Sep. 1991.
|Pate, Filtration: Ozone Compatibility Study of DI Water Filters, Ultrapure Water, pp. 42 50, Sep. 1990.
|Citing Patent
|Filing date
|Publication date
|May 16, 1996
|Jul 8, 1997
|Illinois Water Treatment, Inc.
|On-line ozonation in ultra pure water membrane filtration
|Apr 18, 1997
|Jul 28, 1998
|American Scientific Materials Technologies L.P.
|Thin-walled, monolithic iron oxide structures made from steels
|Nov 9, 1994
|Sep 29, 1998
|American Scientific Materials Technologies L.P.
|Thin-walled, monolithic iron oxide structures made from steels, and methods for manufacturing such structures
|Jan 17, 1997
|Nov 10, 1998
|Orango Corporation
|High-purity water producing apparatus utilizing boron-selective ion exchange resin
|Jun 5, 1997
|Jul 27, 1999
|Lucid Treatment Systems, Inc.
|Method and apparatus for recovery of water and slurry abrasives used for chemical and mechanical planarization
|Dec 16, 1997
|Dec 7, 1999
|Limaye; Santosh Y.
|Fluid separation module having a porous monolithic core
|Nov 18, 1999
|Jun 12, 2001
|Speedfam-Ipec Corporation
|Method and apparatus for immersion treatment of semiconductor and other devices
|Jul 11, 2000
|Sep 4, 2001
|Z Cap L.L.C.
|Method and apparatus for immersion treatment of semiconductor and other devices
|Dec 31, 1997
|Feb 19, 2002
|David R. Stewart
|Methods to remove metals from water
|Apr 26, 1999
|Apr 30, 2002
|Lucid Treatment Systems, Inc.
|Apparatus for separation and recovery of liquid and slurry abrasives used for polishing
|Feb 17, 1999
|Oct 8, 2002
|American Scientific Materials Technologies, Lp
|Methods of making sintered metal oxide articles
|Mar 19, 2001
|Nov 19, 2002
|Linica Group, Ltd.
|Apparatus and process for separation and recovery of liquid and slurry abrasives used for polishing
|May 25, 2001
|Nov 4, 2003
|Z Cap, L.L.C.
|Method and apparatus for immersion treatment of semiconductor and other devices
|Feb 28, 2003
|Nov 30, 2004
|Gerard F. Tempest, Jr.
|System and method for water purification
|Dec 22, 1998
|Apr 26, 2005
|Shin-Etsu Handotai Co., Ltd.
|Silicon wafer storage water and silicon wafer storage method
|Dec 11, 2003
|Mar 3, 2009
|Whirlpool Corporation
|Solvent cleaning process
|Feb 16, 2006
|May 12, 2009
|Gtc Biotherapeutics, Inc.
|Clarification of transgenic milk using depth filtration
|Mar 9, 2010
|Selecto, Inc.
|Modular fluid purification system and components thereof
|Apr 13, 2010
|Whirlpool Corporation
|Non-aqueous washing machine and methods
|Jun 22, 2010
|Whirlpool Corporation
|Fabric laundering apparatus adapted for using a select rinse fluid
|Apr 12, 2005
|Nov 23, 2010
|Whirlpool Corporation
|Dry cleaning method
|Nov 30, 2010
|Lumimove, Inc.
|Electroactivated film with polymer gel electrolyte
|Jun 14, 2011
|Lumimove, Inc.
|Electroactivated film with electrocatalyst-enhanced carbon electrode
|Jun 28, 2011
|Whirlpool Corporation
|Methods and apparatus to accelerate the drying of aqueous working fluids
|Jun 21, 2006
|Aug 9, 2011
|Crosslink Polymer Research, a division of Lumimove, Inc.
|Signal activated decontaminating coating
|Sep 11, 2012
|Whirlpool Corporation
|Non-aqueous washing apparatus and method
|Aug 10, 2009
|Jul 9, 2013
|General Electric Company
|Hybrid multichannel porous structure for hydrogen separation
|Mar 15, 2013
|Dec 31, 2013
|Debasish Mukhopadhyay
|Method for high efficiency reverse osmosis operation
|Mar 12, 2013
|Feb 4, 2014
|Debasish Mukhopadhyay
|Method for high efficiency reverse osmosis operation
|Nov 2, 2009
|Mar 4, 2014
|General Electric Company
|Hybrid multichannel porous structure for hydrogen separation
|Jan 26, 2006
|Jun 24, 2014
|Debasish Mukhopadhyay
|High purity water produced by reverse osmosis
|Nov 1, 2012
|Jul 7, 2015
|Debasish Mukhopadhyay
|Method for high efficiency reverse osmosis operation
|Dec 21, 2012
|Jul 26, 2016
|Infineon Technologies Austria Ag
|Power converter circuit with AC output
|Jan 30, 2008
|Aug 16, 2016
|Infineon Technologies Ag
|Method of forming a non volatile memory device using wet etching
|Jan 8, 2013
|Aug 23, 2016
|Infineon Technologies Austria Ag
|Power converter circuit with AC output and at least one transformer
|Dec 30, 2013
|Aug 30, 2016
|Debasish Mukhopadhyay
|Method for high efficiency reverse osmosis operation
|Mar 28, 2002
|Oct 2, 2003
|Eugenio Bortone
|Apparatus and method for improving the dimensional quality of direct-expanded food products having complex shapes
|Feb 28, 2003
|Dec 4, 2003
|Showalter Dan Joseph
|Electromagnetic clutch assembly having enhanced torque throughput
|Jan 9, 2004
|Nov 18, 2004
|Dhv Water B.V.
|Apparatus for the purification of water
|May 17, 2004
|Feb 3, 2005
|Axtell Holly C.
|Multi-functional protective fiber and methods for use
|Dec 11, 2003
|Jun 16, 2005
|Unilever Home & Personal Care Usa, Division Of Conopco, Inc.
|Solvent cleaning process
|Feb 4, 2005
|Sep 8, 2005
|Gtc Biotherapeutics, Inc.
|Methods of protein fractionation using high performance tangential flow filtration
|Jul 21, 2005
|Nov 24, 2005
|Gtc-Biotherapeutics, Inc.
|Methods of tangential flow filtration and an apparatus therefore
|Dec 9, 2004
|Jun 15, 2006
|Nick Masiello
|Method of purifying recombinant MSP 1-42 derived from Plasmodium falciparum
|Jan 26, 2006
|Oct 19, 2006
|Debasish Mukhopadhyay
|High purity water produced by reverse osmosis
|Jun 29, 2005
|Jan 4, 2007
|Ehud Levy
|Modular fluid purification system and components thereof
|Jun 21, 2006
|May 24, 2007
|Crosslink Polymer Research
|Signal activated decontaminating coating
|Feb 16, 2006
|Aug 16, 2007
|Gtc Biotherapeutics, Inc.
|Clarification of transgenic milk using depth filtration
|Sep 16, 2008
|Apr 2, 2009
|Fujifilm Corporation
|Focal point detection device and image capture device
|Jul 30, 2009
|Daniel Pak-Chum Shum
|Method of Forming a Non Volatile Memory Device
|Jun 26, 2008
|Nov 26, 2009
|Lumimove, Inc. Dba Crosslink
|Electroactivated film with electrocatalyst-enhanced carbon electrode
|Jun 26, 2008
|Nov 26, 2009
|Lumimove, Inc. Dba Crosslink
|Electroactivated film with layered structure
|Nov 26, 2009
|Lumimove, Inc. Dba Crosslink
|Electroactivated film with polymer gel electrolyte
|Nov 26, 2009
|Lumimove, Inc. Dba Crosslink
|Electroactivated film with immobilized peroxide activating catalyst
|Jul 18, 2007
|Dec 24, 2009
|Parekh Bipin S
|Apparatus and method for conditioning an immersion fluid
|Feb 10, 2011
|General Electric Company
|Hybrid multichannel porous structure for hydrogen separation
|May 5, 2011
|General Electric Company
|Hybrid multichannel porous structure for hydrogen separation
|Aug 24, 2005
|Oct 27, 2009
|Diversified Technologies Services, Inc.
|Method in treating aqueous waste feedstream for improving the flux rates, cleaning and the useful life of filter media
|Jul 21, 2003
|Aug 27, 2008
|Process for efficient removing organic pollutant in water by catalysis and ozonization
|Jul 8, 2004
|Jan 11, 2006
|Peter Taboada, S.l.
|Water treatment system for haemodialysis
|Nov 19, 2013
|Sep 7, 2016
|Lance Energy Services Llc
|Functionalized ceramic membranes for the separation of organics from raw water and methods of filtration using functionalized ceramic membranes
|Nov 19, 2013
|Sep 7, 2016
|Lance Energy Services Llc
|Functionalized ceramic membranes for the separation of organics from raw water and methods of filtration using functionalized ceramic membranes
|Dec 30, 1998
|Jul 8, 1999
|Basx Systems, Llc
|Methods to remove metals from water
|May 19, 1999
|Jan 6, 2000
|Speedfam Corporation
|Method and apparatus for immersion treatment of semiconductor and other devices
|Sep 30, 2014
|Apr 9, 2015
|Ultrapure water production apparatus
|U.S. Classification
|210/651, 210/636, 210/653, 210/650, 210/500.26, 210/900
|International Classification
|Cooperative Classification
|European Classification
|Feb 26, 1996
Owner name: ILLINOIS WATER TREATMENT, INC., PENNSYLVANIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FILSON, JAMES L.;BHAVE, RAMESH R.;REEL/FRAME:007825/0939
Effective date: 19960219
|Oct 28, 1999
|Fee payment
Year of fee payment: 4
|Oct 30, 2003
|Fee payment
Year of fee payment: 8
|May 4, 2004
Owner name: USFILTER PROCESS WATER SYSTEMS, INC., ILLINOIS
Free format text: CHANGE OF NAME;ASSIGNOR:ILLINOIS WATER TREATMENT, INC.;REEL/FRAME:014588/0720
Effective date: 20030401
|Sep 10, 2004
Owner name: USFILTER PWS INC., COLORADO
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:USFILTER PROCESS WATER SYSTEMS, INC.;REEL/FRAME:015098/0542
Effective date: 20040731
|Oct 24, 2006
Owner name: SIEMENS WATER TECHNOLOGIES CORP., MASSACHUSETTS
Free format text: MERGER;ASSIGNOR:USFILTER PWS, INC.;REEL/FRAME:018420/0699
Effective date: 20060804
|Oct 16, 2007
|Fee payment
Year of fee payment: 12
|Apr 11, 2011
Owner name: SIEMENS WATER TECHNOLOGIES HOLDING CORP., PENNSYLV
Free format text: MERGER;ASSIGNOR:SIEMENS WATER TECHNOLOGIES CORP.;REEL/FRAME:026106/0467
Effective date: 20110401
|Apr 15, 2011
Owner name: SIEMENS INDUSTRY, INC., GEORGIA
Free format text: MERGER;ASSIGNOR:SIEMENS WATER TECHNOLOGIES HOLDING CORP.;REEL/FRAME:026138/0593
Effective date: 20110401


text:
Toner cartridge is specially formulated for increased print consistency and continuity even on rough papers. Ensure extraordinary print quality and superior reliability. Cartridge is designed for use in Xerox Phaser 6250.
Xerox Phaser Printers:
©Copyright 1996-2016 ANTOnline (Atlanta Network Technologies Inc) Atlanta Network Technologies, Inc is not responsible for typographical or photographical errors. Prices and specifications are subject to change without notice.

subset: commoncrawl


text:
GREENBURGH, N.Y. -- Playoff experience isn't high on Rangers coach John Tortorella's list of critical components for a playoff contender.
"The more guys without playoff experience the better as far as I'm concerned," Tortorella said. "There's not going to be a lot of explanation to them. We just want them to play. I think having innocence in these situations is very good for a hockey club."
Luckily for Tortorella, he's going to have more than enough players who have never skated in the NHL playoffs.
The Rangers have eight players on their roster who will be preparing to potentially make their playoff debut when the Blueshirts travel to face the top-seeded Capitals on Wednesday night. Most of the players will be counted on to play key roles for the Rangers and could help determine their fate.
"We just want to play hockey," Rangers rookie forward Derek Stepan said. "Gotta go out and play our team concepts and do what we've done all year long. Obviously it's going to be a little different that eight guys don't know what it's like yet, but I think we'll be all right."
The list of Rangers newcomers to the playoffs spans across all positions, including Stepan and fellow forwards Brandon Prust, Brian Boyle and Mats Zuccarello; defensemen Ryan McDonagh, Michael Sauer and Matt Gilroy; and goalie Chad Johnson.
Of that group, Stepan, Prust, Boyle, McDonagh and Sauer are the most active contributors and play key minutes, while Gilroy and Zuccarello could be healthy scratches in the playoffs and Johnson is the backup to Henrik Lundqvist.
Talk to the guys who have not played in the playoffs and the biggest thing that sticks out is their excitement. For some of the guys, like Stepan and McDonagh, they're getting the chance in their rookie season. Others, like Boyle and Prust, have a few seasons under their belt.
"A lot of guys don't have that experience but there are a lot of guys that do and I think the guys that don't are going to be really excited and really hungry going out there," Sauer said. "It's something you dream about growing up, playing in the NHL playoffs and winning the Stanley Cup -- and this is the start of it and this is a stepping stone that we had to do and we got here. Now it's a whole new season."
In terms of preparation, the general consensus around the team is that the playoff noobies have to just jump in. They can ask around to the veterans for advice, but as Lundqvist said: "[The] playoffs [are] something you have to experience and learn for yourself."
It's that mentality that has Tortorella enthused about his newcomers heading into the quarterfinals. They all have a blank slate. They haven't felt the pressure of being in those games before and don't have to get caught up in the negatives. They can just go play hockey, as they did down the stretch when the Rangers could afford no breathing room.
"You don't want to overthink anything," McDonagh said. "You want to stay focused mentally and prepare yourself the same way you would for any other game. You don't want to change anything up because it's the playoffs. Same goes for our system and our structure that's why we got here, because we're detailed in those areas and we need to make sure we stick with that."
The intensity of the stretch run was also valuable experience for the group of eight. The last two months of the season were essentially packed with playoff games for the Rangers -- although those games pale in comparison to the pressure that a single postseason game brings.
Just ask the Rangers coach.
"I think this is such a great opportunity for players," Tortorella said. "This is where you get defined, in the playoffs. This is where teams get defined, players are defined."
Wednesday night, that group of eight gets its first crack at greatness.
NEW SEASON FOR GABBY: The playoffs are called a second season, or a new season, for a reason. For Rangers forward Marian Gaborik, a clean slate is appreciated after a down regular season.
Now, it's time for the Rangers' sniper to try and find his groove.
"It's big not just for myself but for everyone," Gaborik said. "It's a motivation and a challenge. I'm very excited for this opportunity we have and we have to grab it."
After blasting 42 goals and tallying 44 assists last year in his first season with the Rangers, Gaborik struggled this year, tallying just 22 goals and 26 assists. He played 14 fewer games and struggled through portions of the season, getting benched amid long stretches without goals.
Tortorella said this season was a struggle for Gaborik, but said Gaborik has to look forward to this opportunity and "express himself as a player," which he believes Gaborik will do against Washington.
"I think Gabby cares," Tortorella said. "If it's one guy, it's a great situation for him. You need to have a short-term memory and move on. You're not defined by regular season play as a player, you're defined as what you do in crucial situations and that's playoff hockey. I know Gabby is willing to grab a hold and try to get this club to where it wants to be. That will go game to game, shift to shift with him."
While he might have had a down season, Gaborik's confidence in his team hasn't taken a hit. He provided perhaps the only trash talking line by any Ranger, as tame and unintentional as it might've been.
"I don't think [Washington] wanted to play against us. I think they would rather have played Carolina because they have a good record against them," Gaborik said. "We have to be ready and make sure we play good defensively and make sure we know where their top guys are on the ice and create offense and make sure we get a lot of shots and create chances."
GET SOME POWER: The Rangers power play isn't blossoming heading into Game 1, as the Blueshirts went just 14-of-72 on the power play in their final 21 games. Finding ways to take advantage during a power play, while also limiting Washington's advantages, will be important for the Rangers against the Capitals.
"Special teams are going to the key. We know we have to be disciplined," Gaborik said. "They have a good power play and if we get on the power play -- we practiced it yesterday -- we know they are going to come out hard and be aggressive. So we need to move the puck quick and make sure we create chances and do the job."
Tortorella said that he's still working on the groupings for the power play, but did say that Gaborik could help the Rangers there if he finds his stride in the playoffs.
"[In the] playoffs, special teams is always a huge component of trying to win a series," defenseman Marc Staal said. "I think it will be big. Coming up this week we obviously need to pay attention to defense in our zone and making sure we're doing those things properly to try and give ourselves a chance to score."
CHAMPIONSHIP RESUME: Tortorella, who won a Stanley Cup with the Lightning in 2004, said his coaching staff will try and be "guidance counselors."
Torts said he's grown since '04 as that guidance counselor.
"This is a new team for me," Tortorella said. " I grew with that team in Tampa. I changed over the years with Tampa. ... If you're still trying to teach the lessons and be the person that you were back then, it's disrespectful to the players, so we've all grown together here and I think coaches have to go along with that as your players start growing as people and players."
NO HINTS: Tortorella will not divulge any information about the lines or the roster spots for Wednesday's game, but here were the lines (in no order) during practice Tuesday: Zuccarello-Chris Drury-Sean Avery-Erik Christensen; Gaborik-Artem Anisimov-Vinny Prospal; Stepan-Brandon Dubinsky-Ruslan Fedotenko; Prust-Boyle-Wojtek Wolski.


text:
Title contention and massive disappointment are both possibilities for the 2013-2014 Rockets.
Almost five years ago, Houston GM Daryl Morey explained his long-term team-building strategy on a stage at a conference in Boston.
Basketball, he said, is "not like many professions." In most lines of work it is enough to be really good. But in basketball, you have to be the absolute best, No. 1 out of 30, or else you have failed. Twenty-nine teams go home unhappy. Run your team making only conservative decisions and end up, almost certainly, as one of the 29 losers -- so that's not what Morey intended to do.
And Morey has been a man of his word, rolling the dice every which way in attempts to get top-shelf players. He went all-in trying to woo Chris Bosh in the summer of 2010. He traded for Pau Gasol in the Chris Paul deal that fell apart at the direction of David Stern.
Most teams shy away from tough-to-value players, but Morey has signed a ton of them. Ron Artest (as Metta World Peace was known then) was on Rockets' roster when Morey spoke at the MIT Sloan Sports Analytics conference. Since then, effective-in-short-minutes backups like James Harden, Jeremy Lin and Omer Asik have beguiled executives.
Morey signed them all to big deals. He also drafted Royce White, a tantalizing talent with a well-documented history of mental illness that has kept him from the NBA court.
Take the right big risks, and you'll still probably end up as one of the 29 losers -- that's the math -- but at least you have a chance.
Which is precisely where Morey has steered the Rockets now, after trading for James Harden a year ago, and then luring Dwight Howard to Houston in free agency.
Everyone knows Howard was the best player on the free-agent market; the contest to sign him has been called a "sweepstakes."
But he's also an enigmatic player with a history of back trouble, coming off the two worst seasons of his career at an age when most players at his position would be peaking. They're not ready to start ordering championship rings in Houston, but now rings are among the things that really could happen. Among the other possibilities is what happened to the last team that signed Howard: The Lakers are in total disarray.
It's not about knowing the future. It's about maximizing the likelihood of being the last team standing.
Vegas says that adding Dwight Howard to a roster of Harden, Omer Asik, Jeremy Lin, Chandler Parsons, Patrick Beverley, Donatas Motiejunas, Terrence Jones, Greg Smith & Co. gives Houston about a 10-to-1 chance of winning the title this season. Before the Howard signing that was 20-to-1, according to Bovada. And bad as 10-to-1 sounds, only the Heat and Thunder have better chances. The Rockets are in the hunt with teams like the Bulls and Clippers.
But like the Bulls and Clippers, the Rockets are wrestling with profound risk. The teams' key unanswered questions:
Is Dwight Howard healthy?
The Rockets have yet to complete their physical of Howard. It's hard to believe anything they'd find would have the potential to make them walk away from free agency's greatest coup.
But what they find will have to matter for a franchise that is only a few years removed from envisioning Yao Ming as the cornerstone of a title team. Yao's premature retirement due to foot problems still hangs over the Rockets -- Yao's only five years older than Howard, but last played meaningful minutes when he was about the same age Howard is now.
The good news is that Howard has not had a career like Yao, Greg Oden or other famously injury-prone players. He has been a durable performer over the past nine years, having missed just 25 games over the first nine years of his career. He was even, compared to most other NBA players, pretty good last season while playing injured. The Lakers were better with him on the floor, even if his PER was right there with Robin Lopez's, and well behind, say, J.J. Hickson's.
It's no lock Howard will ever return to his wicked-high, contender-anchoring production of three years ago. Back then his seemingly invincible body was his greatest advantage. Now, like all aging players, he's trying to learn how to help a team as much without deploying so much body-taxing explosiveness.
Can the Rockets still play fast?
The Rockets used a clever style to turn a mediocre roster into the NBA's sixth-best offense: They played at the NBA's fastest pace. As they flew down the court, they looked for two kinds of shots: those behind the 3-point line and those at the rim. Those shots aren't easy to get against set defenses, but early in the clock, with creative ball handlers like Harden and Lin doing their thing, there are buckets to be had without having to sweat matchups and all that.
In other words: These players can score, if they play fast.
If they can play fast with post-back injury Howard, however, they will have figured out a trick that befuddled the Lakers' coaching staff.
It's not how most fans see the game, but there are great post-up opportunities very early in the clock; the best time to score from the post is before there's help. Howard could, in theory, be part of this attack. But it would mean doing the hard work of defending the rim, warring for the rebound and then racing the floor. It's a tall order, and not something any player can do for 40 minutes a night.
Which brings up ...
The Omer Asik issue
Asik is not a superstar, by name. But he's a very fine defender. He was on the floor for 62 percent of the Rockets' minutes last season, during which time the team was very good, outscoring opponents by six points per 100 possessions. During the other 38 percent of the season the team was so bad that all the other big-minute Rockets -- Harden, Chandler Parsons, Lin -- finished the season with negative plus/minus ratings.
In other words, we think of Howard joining a pretty good team, and making it better. But in fact, by sending Asik to the bench, Howard is taking the floor with four guys who needed heroic defensive help just to win 45 games. The great news for the Rockets is that they'll have finally solved last season's crisis -- no good backup for Asik -- but there's still no getting around the reality that Howard is benching one of the very best Rockets, and it's no surprise Asik's not happy about it and has asked for a trade.
The Rockets believe they need Asik and won't trade him, however. Not to mention: It might make sense some nights to close games with Asik on the floor instead of Howard.
Keeping everybody focused on the bigger picture will be a massive challenge for coach Kevin McHale.
McHale is a legend as a player. But we still don't know much about him as a coach. He has won a little less than half of the 242 regular-season games he has coached, with last season's 45-win Rockets team his best full season. This past spring he won the first two playoff wins of his coaching life.
And without a good post player, the man who was once lauded for his top-shelf post moves has scarcely been able to play his best coaching cards. Perhaps he will coach Howard better than he can coach anybody.
But as far as devising the best team scheme, or massaging all the egos enough to keep everyone focused on the bigger goal, we don't yet know how he ranks.
Will there be enough basketballs?
Superstars drive the championships in the NBA, it's generally bad strategy to leave them. But did you notice that both Rockets stars, Howard and Harden, are on the short list of players who could still be teamed with superstars but chose otherwise? It's not a stretch to say that Howard wanted the ball bad enough to flee Kobe Bryant. Harden played in the shadow of Kevin Durant and Russell Westbrook in Oklahoma City. The Thunder reportedly offered Harden $55 million over four years to stick with a team that had just made the Finals. Harden rejected the deal, convinced he was worthy of leading man dollars and status. The Thunder traded Harden to Houston, where he has more than proved his point.
It's not a tale of selfishness. Harden and Howard deserve the ball, and know what to do with it. But if the Rockets are counting on Harden and Howard being happy in any role so long as they're winning, well, history would argue otherwise.
Even before Howard, there have been issues on the Rockets with how much Harden needs the ball. For instance, Lin is best with the ball, too, and struggled to be effective playing with Harden. Imagine if Lin and Howard develop into a potent pick-and-roll combination. Will that sit well with the bearded shooting guard?
Teams wooing Howard tried to scare him off the Rockets by pointing out that Harden likes to shoot almost as much as Bryant does, which is something of a stretch -- Harden passes more -- but it's in the neighborhood of true.
You can say that Harden shot that much only because the Rockets needed him to, and with efficient-scoring Howard on the court it'd make more sense to hand it over. But should Harden shoot at anything like Bryant levels, will we see the return of the gloomy, less productive Howard who played for the Lakers last season?
A roster with little wiggle room
By the time the smoke has cleared and Howard is officially a Rocket -- the news conference is expected at the end of this week -- the Rockets will likely have the ability to add minimum contract players and somebody with the mini midlevel. And that's it.
In other words: Andrei Kirilenko isn't walking through that door. That means the starting power forward will be some combination of Jones or Motiejunas -- who are young and promising, but come with a lot of unknowns.
There are a lot of question marks about how it all fits together. It might work, but if it doesn't, this is a contender in need of a major trade, which is almost the same as not being a contender at all.
Patrick Beverley -- who has emerged as a very good point guard for the Rockets -- had the key line in this Michael Wallace article about how Howard will fit in Houston: "Nobody," says Beverley, "has a crystal ball."
So true. We simply don't know what will happen.
One thing that could happen, though, is that the Rockets could win a title in the next few years, which is new, and a credit to the franchise.


text:
Skip to comments.The nobody needs fallacy
Posted on 01/07/2013 7:04:17 AM PST by marktwain
Does anyone really need old family snapshots? Pictures of your child as a baby, or of your grandparents on their honeymoon have no monetary worth and nearly no practical value. What can you do with them, besides looking every few years. Would you be OK with government taking away by an arbitrary decree?
We dont need apples. Pears are close enough and can be used in the same recipes. Would you be OK with apple growing being prohibited?
Nobody needs to read Jonothan Swift. Should the books be destroyed for their supposed advocacy of cannibalism?
When we are robbed of snapshots, apples or books, we are robbed of more than sentimental value we are robbed of free choice! Applied to guns, the claim that we dont need them though faulty in itself is first and foremost ethically offensive to the core! To have a master decide if you may have a pear but not an apple, or a smoothbore shotgun instead of a rifle, or any other personal aspect of your life is the very definition of slavery. Its the major component in learned helplessness. When our government officials behave as domestic abusers, its time to start wondering why.
The gun banners are right on one thing: weapons are a special case, just not the way they think. I may have a gun that I do not need. It could be less than a wallhanger, just something taking up space in the attic. But that lack of purpose goes away the second somebody wants to rob me of it defending against brigandage becomes that guns primary purpose.
How about: Nobody needs 24/7 media coverage of these mass killings. It is very dangerous and leads to the copycat effect where unbalanced people are given an incentive to kill masses of innocents in order to become famous.
While many statists would agree to limit the First Amendment here, many others woud see the point.
Nobody needs health insurance, until they do.
Nobody needs liability insurance, until they do.
And guess what? Our govt. says we have to buy those.
Why is this so hard for people?
I can certainly see the enviros jumping on the argument with a "no family needs more than one car" position.
The Founding Fathers could not possibly foresee high speed printing presses.
Therefore nobody needs a high speed printing press.
A single page, manual press will do.
Liberals bitch about killing the trees, yet, their favorite hangouts are bookstores with coffee shops.
And why one of their most favorite hangouts in Denver, the Tattered Cover, is dying. If it wasn't for the attached coffee shop it would have been a goner long ago.
In Austin (the liberal/socialist mecca of Texas) they decided to clear cut thousands of trees in order to install, get this, a solar energy station.
Yep, they is some real smart cookies them greenies.
There is a distinction between things that are needed because they are necessary for survival or for living a life proper to a rational being and things that are simply wanted for whatever reason. Something may not be needed but could still be wanted.Everyone has their own hierarchy of values that they use to make decisions about what they want to gain or keep.In a free society it is up to the individual to decide for himself what values he want to pursue, in what order, and how.
It's called the bill of rights
Not the bill of needs.
From each according to their abilities, to each according to their needs. -Marx
When you surrender to the idea that someone can dictate or even suggest your needs, and how to apply your abilities you are in essence a slave.
Marx just made it sound noble.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.


text:
Wednesday, August 29, 2012
As the community tries to make sense of the death of Dana Woods, her mother has reached out to The Independent to share her thoughts about her child, who had the best of her life ahead of her.
"Dana is a sharp kid," said Jennifer Hill on Wednesday morning. "My daughter is a good girl."
Hill said her daughter was out on Saturday night doing a favor for her – taking her cousin home to the child's mother in Pinopolis and then picking up her friend June Guerry to give her a ride home.
"(Dana and June) weren't going out," Hill said. "Dana doesn't do that sort of thing. She was actually doing a favor for me.
"June and Dana loved each other so much. And I know Dana wants June found. Dana would have done anything to protect June so she could go home to her baby, and we're all praying that June is found safe. I know Dana would want that."
Woods, 18, had finished her final year of high school as a home schooled student with Berkeley County's K-12 Virtual Charter School program. She was simultaneously taking college courses at Trident Tech.
"She is a sharp kid," her mother said. "She had already finished two years of college courses. Dana wanted to go to law school eventually, at South Carolina. She was just beginning to get all the things she's wanted in life, a new car, a phone, a computer. She has so much to look forward to and so much ahead of her."
Hill continually called her daughter a good girl, a "techie," one who had to have the latest, the newest and the best in technology.
"Dana has three computers in her room," her mother said. "A desktop, a laptop and a tablet, and was often on at least two of them at the same time.
"She also has a Smart Phone. And that's how I knew something was wrong because she is never off that Smart Phone."
Hill remembered her daughter as one who would go out of her way to help and protect others and would often put their needs ahead of her own.
"She would often get off work at 8 p.m. when she worked at Burger King, come home and take a nap and then be back up there at 1 a.m. because there was a boy she worked with who needed a ride home and she would go back to give him a ride home all the way to Cross," Hill said.
Dana Woods was loved by many people, her mother said.
"She was stubborn and hard headed and often she was a pain in the butt, but she worked her butt off so she could get ahead in life," Hill said. "She was driven and ambitious and had so much ahead of her."
Hill said at 18, Dana had just received her first credit card.
"She came up to me and said, 'Look Mama, I have a credit card.' She was so proud of that and so responsible with her money. She didn't just take life by the horns. Dana was the bull that was charging ahead."
Hill remembered a story about Dana in her class finals review and how her daughter was always one to play the practical joke: "In class before the teacher came in, Dana had grabbed the remote for the projector and while the teacher was giving instructions Dana was changing the image size on the screen. The other students were laughing and the teacher didn't know what the problem was with the projector.
"Dana couldn't help it and busted out laughing on the joke she played on the teacher. She was a prankster. She liked to mess with people like that. Her teacher said she'd be sure to get her back next semester."
As a mother now deals with the void left behind by her daughter and struggles to cope with every parent's horror, Hill's thoughts turn to hers and Guerry's families. Hill wants people to know about her daughter's love for June Guerry.
"Dana had this need to protect," her mother continued. "Dana would do anything to protect those she loved. I suspect that's what happened to her. She was protecting June."
The days now have lost their color for a mother struggling to make sense of the loss of a daughter she loved more than anything in the world.
"Dana was all set to get her life going," she said. "She had so much to look forward to out of life. Dana was such a good girl."
© 2016 The Journal Scene an Evening Post Industries company. All Rights Reserved.
Registration on or use of this site constitutes acceptance of our Terms of Service, Privacy Policy and Parental Consent Form.