Abstract: Apparatus for supplying moisture to an envelope, having a body portion and a flap portion, the apparatus including, a substantially solid-rectangle-shaped pad made of a material capable of upwardly transferring fluid by capillary action, a device for supplying fluid to the pad, the fluid supplying device including a source of supply of fluid, the fluid supplying device including an elongate well having an elongate substantially rectangularly-shaped base wall, the well including a fluid inlet tube depending from the base wall and removably connected in fluid flow communication with the fluid supply source, the well including a pair of elongate substantially rectangularly-shaped and oppositely-spaced side walls, the well including a pair of substantially rectangularly-shaped and oppositely-spaced end walls extending between the side walls, the side and end walls extending upwardly from the base wall, the well including a plurality of upright posts located at spaced intervals longitudinally of the length of the

Abstract: To correctly splice two films to each other in the end-to-end relationship, a film splicer includes as essential components a base platform, a film guide mechanism arranged on the base platform, an arm member adapted to be turnably depressed against the upper surface of the film guide mechanism by actuating a handle for a cutter holder, an adhesive tape feeding mechanism, and a pair of tape cutters arranged on the lower surface of the arm member for cutting an adhesive tape in a film splicing operation region corresponding to the width of each film to be spliced. The adhesive tape feeding mechanism is composed of an adhesive tape unrolling member, a holding member for temporarily holding the foremost end part of the unrolled adhesive film, and an opposing pair of adhesive tape folding-back members for folding back the unrolled adhesive tape at a predetermined position in front of the film splicing operation region.

Abstract: A plurality of webs drawn from respective supply rolls forms a core stack which is passed through a single-level press to press boards from the press stack formed by applying cover foils to the core, the latter extending over and forming part of a transport belt that becomes part of the boards. Once the pressed board forming part of the belt is advanced from the press, the pressed board can be cut and trimmed from the belt.

Abstract: A tape applicator for application of a double-sided adhesive tape to a member which can be cut and assembled to form a frame for glazing for a skylight, a window or a door. The tape applicator includes a spindle for accepting a plurality of rolls of tape and apparatus for guiding the frame member past the roll of tape to permit accurate and dependable application of the tape to the frame member. A spring mounted block urges the tape into tight, adhesively bonded relation with the frame member at the desired location. The guiding apparatus is removable to allow selection and installation of an appropriate guiding apparatus configured to accept the cross-sectional size and shape of the particular frame member to which it is desired to apply tape. A wall acts as a stop to align the tape with the frame member. When the tape from a particular roll has been exhausted, the remaining core can be pushed past the wall into a recess to allow advancement of the next available roll into position.

Abstract: A production line for manufacturing wooden I-beams wherein a pair of grooved flanges are conveyed along opposite sides of a train of web members and converged so that the web longitudinal edges are inserted into the chord grooves is disclosed. The flanges are each sequentially fed into left and right hand sides of the assembly line through a cam type flange feeder and a resiliently mounted hold-down member automatically orienting the flanges with the flange grooves facing inwardly. A lugged web feeder engages a longitudinal edge of each web to laterally convey same, or random web lengths, into the upstream end of the assembly machine. A web bottom drive engages the web undersides to convey same into contact with the flanges while eliminating overhead clutter to enable easy access to the web and flange members for manual intervention.

Abstract: A process for epitaxially growing a compound semiconductor layer containing at least arsenic on a single crystal silicon substrate, which prevents the silicon impurity from intruding said compound semiconductor layer. The process comprises supplying one of the starting material gas, ASH.sub.3, into the reaction furnace to effect growth, but in such a manner that the AsH.sub.3 gas is pyrolyzed in advance to thereby supply arsenic alone either in an atomic or a molecular state. The GaAs layer is thus epitaxially grown on a single crystal silicon substrate in the crystal growing chamber, i.e., the reaction furnace in the apparatus, under an atmosphere comprising atomic or molecular arsenic at a temperature in the range of from 400.degree. to 650.degree. C. and at a vacuum degree of about 0.1 Pa. By thus epitaxially growing GaAs layer under an atmosphere comprising atomic or molecular arsenic, the intrusion of silicon impurity into the GaAs layer during its growth can be effectively prevented.

Abstract: A high precision electrode position controller is provided for use in a semiconductor etching device. The electrode position controller, system, and method of use can accurately and repeatedly position a dry etch electrode within the etch chamber without having to open the chamber and manually move the electrode. Moreover, the actual gap between electrodes can be calibrated each time the etching device is turned on. Frequent calibration of actual electrode position ensures the electrodes are positioned parallel to each other and at an optimal distance therebetween. Accurate positioning of the electrodes provides a more precise etch rate and a more uniform etch across the wafer surface. By repositioning the electrodes and maintaining parallelism, varying types of material can be accurately etched.

Abstract: The present invention generally relates to manufacturing apparatus, method of manufacture, and products manufactured thereby and more particularly to an integral three-dimensional object (6, 15) formed from individually contoured laminations (4, 62) of the same or gradually varying shape, successive laminae of that object being produced out of thin sheet or powder based materials (1, 60) through the cutting, fusing or physiochemical property changing action generated by a computer directed beam (7) of concentrated energy or matter, successive substantially planar laminations (4, 62) of that object (6, 15) being automatically stacked together for step-wise laminar buildup of the desired object (6, 15).

Abstract: Method for forming a ceramic circuit board by forming a metal circuit pattern on a ceramic board through an active metal ingredient-containing brazing material and removing an unnecessary part of the brazing material by chemical liquor treatment.

Abstract: Etching of an article is carried out by maintaining the article at a temperature at which the vapor pressure of etching gas molecules becomes equal to or higher than the pressure of etching gas and the vapor pressure of neutral radicals contained in a plasma becomes equal to or lower than the pressure of an etching gas. An etching pattern with a substantially vertical side profile and extremely small in dimensional shift from the mask can be formed at high precision.

Abstract: A process for selectively etching a substrate 20 having a molybdenum silicide layer 25 with a resist material 26 on portions of the molybdenum silicide layer 25 is described. The substrate 26 is placed into an etch zone 54 and the process gas comprising SF.sub.6 and HBr is introduced into the etch zone 54. Preferably, the volumetric flow ratio of SF.sub.6 :HBr is from about 1:10 to about 1:1, and more preferably, an oxygen containing gas such as O.sub.2 is added to the process gas. A plasma is generated in the etch zone 54 to form an etch gas from the process gas that anisotropically etches the MoSi.sub.x layer 25 with good selectivity and reduced profile microloading.

Abstract: A method and apparatus for dry etching changes at least one of the effective pumping speed of a vacuum chamber and the gas flow rate to alter the processing of an etching pattern side wall of a sample between first and second conditions. The first and second conditions include the presence or absence of a deposit film, or the presence, absence or shape of a taper angle. Various parameter for controlling the first and second conditions are contemplated.

Abstract: A liquid level control structure and a method for its production. The liquid level control structure is comprised of a wafer having substantially flat top and bottom surfaces and a channel for containing a marking fluid. The channel is defined by inwardly sloping walls that extend through the wafer and that join with the top surface of the wafer to define protrusions. The protrusions interact with the marking fluid's surface tension so as to control the location of an unbounded surface of the fluid within the channel.An alternative embodiment liquid level control structure uses a thin film layer deposited over the wafer's top surface that extends over the protrusions to form lips. Those lips interact with the marking fluids surface tension to control the location of the unbounded surface.The methods for producing the liquid level control structures use semiconductor fabrication techniques such as photolithography and anisotropic etching.

Abstract: An etching process allows a selective single-step patterning of III-V or II-VI semiconductor compound devices such as GaAs and InP or CdS and ZnSe in a noncorrosive environment. The etching relies on a maskless laser-assisted technique in a gaseous chlorofluorocarbon ambient, such as gaseous dichlorodifluoromethane and chloropentafluoroethane. Laser-assisted photothermal chemical etching reactions on the III-V or II-VI semiconductor compounds occur in these ambients when the incident fluence from an excimer laser at 248 nm exceeds the melt threshold. This provides a means for thin membrane formation in III-V or II-VI semiconductor compounds, rapid etches and processing of packaged devices or partially fabricated dies. The reduction in processing steps as compared to conventional wet chemical etches provides improvements in yield, reliability and cost.

Abstract: A dry etching method for performing anisotropic etching of a layer of a silicon based material without using a chlorofluorocarbon gas, is proposed. Sulfur halides yielding free sulfur (S) into a plasma under conditions of dissociation by electrical discharge, such as S.sub.2 F.sub.2 or S.sub.2 Cl.sub.2, are used as main components of the etching gas. This S is used for sidewall protection and for improving selectivity during etching, and is removed by sublimation by heating the wafer after etching. Although etching may be achieved by S.sub.2 F.sub.2 alone, suitable measures may preferably be used to increase the S/X ratio of an etching reaction system, which is a ratio of the number of atoms of S to that of X or a halogen, because the layer of the silicon based material is highly susceptible to halogen radicals. Specifically, optimum results may be obtained by (a) adding H.sub.2, H.sub.2 S or SiH.sub.

Abstract: A process for producing a leadframe for a semiconductor including (i) providing nickel or nickel-base alloy plating layers on both sides of a base material including an iron-base material or a copper-base material by electroplating or chemical plating so as to have a single layer thickness in the range of from 3 to 20 microns, (ii) applying a photoresist on both sides of the leadframe material produced in step (i) and forming a leadframe pattern by a patterning process and (iii) subjecting the leadframe material patterned in step (ii) to etching.

Abstract: A method of bleaching a chemical pulp with a gaseous bleaching agent by uniformly impregnating the pulp with a solvent for lignin and that is fully miscible with water but does not significantly swell cellulose so that the availability, of lignin to the bleaching agent is significantly improved, then subjecting the impregnated pulp to the action of the bleaching agent to preferentially attack the lignin for its subsequent solubilization and separation from the pulp.

Abstract: A paper product treated with a degradation product of a polysaccharide derivative comprising a mixture of oligomers of the polysaccharide derivative, a majority of said oligomers having a degree of polymerization such that the oligomer conforms to a rod-like configuration.

Abstract: Tissue papers, in particular pattern densified tissue papers, having an enhanced tactile sense of softness when treated with certain polyhydroxy fatty acid amide softener systems that are biodegradable are disclosed. The polyhydroxy fatty acid amides have the formula: ##STR1## wherein R.sup.1 is H, C.sub.1 -C hydrocarbyl, 2-hydroxyethyl, 2-hydroxypropyl, methoxyethyl, methoxypropyl or a mixture thereof; R.sup.2 is a C.sub.5 -C.sub.31 hydrocarbyl group; and Z is a polyhydroxyhydrocarbyl moiety having a linear hydrocarbyl chain with at least 3 hydroxyls directly connected to the chain.

Abstract: A blade mounting frame is attached to a support structure having an endless forming wire rotatably mounted thereon. At least one turn shoe is mounted to the support structure for guiding the rotating path of the forming wire. A blade assembly attached to the blade mounting frame includes a blade in contact with the wire for removing debris from the forming wire before the debris is caught at a nip between the rotating wire and the turn shoes.

Abstract: The invention relates to the manufacture of moulded objects from a fluidized fiber raw material. The fiber raw material used, is a pulp processed from waste paper by slushing the waste paper in a pulper. All or some part of the waste paper added to the pulper is subjected to a separate controlled dry grinding prior to the slushing in the pulper.

Abstract: Method and apparatus for the distillation of liquids which is particularly suited for the removal of soluble impurities and insoluble and non-volatile particles of 10 microns to 0.2 micron or less in size. A substantially elongated distillation chamber having walls equipped with axially disposed concentric boiling rings spaced from the walls near the bottom, and a packing stop, packing redirector rings for condensed vapor, and a reflux condenser in the upper part of the distillation chamber provide, during distillation, a smooth convective upward flow of distilling liquid and vapor proximate the walls and boiling rings and a smooth convective downward flow of distilling liquid and vapor substantially centrally of the distillation chamber.

Abstract: A discrete impure cresylic acid distillate fraction derived by fractional distillation of a natural cresylic acid feedstock from which tar bases and/or neutral oils have not been removed is subjected to extractive distillation with a polyhydric alcohol extractant and subsequent separation of the discrete cresylic acid fraction. The extractive distillation removes tar bases, neutral oils, undesirable phenolic substances, sulfur compounds, color-forming impurities and odor-imparting impurities.

Abstract: Contaminants are removed from impure propylene oxide by fractionating in a first column to remove overhead essentially all of the pentenes and pentanes and most of the oxygen-containing impurities to provide a partially purified first propylene oxide bottoms fraction, extractively distilling the first bottoms fraction in a second extractive column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a second overhead fraction comprising propylene oxide, hexenes, hexanes, water, residual quantities of pentenes and pentanes and oxygen-containing impurities, extractively distilling the second overhead fraction in a third column using a C.sub.6 to C.sub.10 alkane hydrocarbon extractive distillation agent to form a third bottoms fraction comprising the extractive distillation agent, propylene oxide, hexenes, hexanes, residual quantities of pentenes and pentanes and water, and extractively distilling said third bottoms fraction in a fourth column using a C.sub.6 to C.sub.

Abstract: Crude propylene oxide is purified by a distillation process wherein it is (a) extractively distilled in a first column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a first overhead fraction comprising propylene oxide, C.sub.5 -C.sub.7 hydrocarbons, methanol, water and oxygen-containing impurities, (b) wherein the first overhead fraction is separated in a plurality of intermediate distillation columns to provide an intermediate propylene oxide overhead fraction consisting essentially of propylene oxide and water, and (c) the intermediate propylene oxide overhead fraction is charged to a final distillation column using a C.sub.2 to C.sub.6 alkylene glycol extractive distillation agent to form a final overhead fraction consisting essentially of propylene oxide.

Abstract: A process for the production of pure distilled isocyanates in which the corresponding amine is reacted with phosgene in a suitable solvent and working up of the isocyanate containing solution obtained by multistage distillation into pure isocyanate, pure solvent and a residue. The residue is then charged to a vessel containing at least one hydrocarbon having a high boiling point. The contents of this vessel are then heated with stirring to distill off any free isocyanate present. The remaining residue is a solid which may be disposed of readily.

Abstract: Method for providing a proportioned gas flow of triisobutylaluminum from liquid triisobutylaluminum having isobutene admixed therein. The liquid is preheated sufficiently to evaporate the isobutene therefrom but leaving the triisobutylaluminum substantially in liquid phase. The vaporized isobutene is separated from the liquid triisobutylaluminum, and subsequently the triisobutylaluminum from which isobutene has been removed is evaporated. Preheating is conducted at a temperature of 30.degree.-40.degree. C. The evaporation of liquid triisobutylaluminum is conducted at a temperature of 40.degree.-60.degree. C.

Abstract: Waste solution of developer, used as developer for a positive type photo resist and containing tetraalkylammonium hydroxide is neutralized with carbon dioxide, and it is filtered through a separation membrane. After removing precipitates of insoluble organic substances, it is sent to an anode chamber of an electrolytic cell divided by a cation exchange membrane, and electrolysis is performed. Low grade organic compounds in aqueous solution of tetraalkylammonium hydroxide obtained from a cathode chamber of a first stage electrolytic cell are oxidized and decomposed and are then supplied to an anode chamber of the next stage electrolytic cell, and high purity tetraalkylammonium hydroxide aqueous solution is obtained from the cathode chamber.

Abstract: The novel process of the invention produces chlorine dioxide by feeding an aqueous solution of chloric acid to a chlorine dioxide generator. The aqueous solution of chloric acid is reacted with a reducing agent in the chlorine dioxide generator to produce chlorine dioxide and a spent chloric acid solution containing metallic impurities. A portion of the spent chloric acid solution containing metallic impurities is reacted with a basic compound selected from the group consisting of alkali metal hydroxides, and alkali metal carbonates in a neutralizing zone to form a precipitate of the metallic impurities and an alkali metal chlorate solution. The precipitate of the metallic impurities is separated from the alkali metal chlorate solution and the alkali metal chlorate solution fed to an ion exchange compartment of an electrolytic cell having an anode compartment, a cathode compartment, and at least one ion exchange compartment between the anode compartment and the cathode compartment.

Abstract: The invention concerns a device and a method for removing nitrogen compounds from an aqueous liquid containing nitrogen oxides (NO.sub.x) and/or nitrates (NO.sub.3.sup.-). It comprises an electrochemical cell (10) with a cathode and an anode and a current source applied thereto. According to the invention, the cell is divided by a cation selective membrane into a cathode compartment (2) to be filled with said liquid, and an anode compartment (3) to be filled with an anolyte containing an aqueous solution of an alkali or hydrogen halide such as sodium bromide or sodium chloride, and the membrane (1) is constituted by a microporous fabric of PTFE.

Abstract: A method is provided for microelectropolishing a transmission electron microscopy nonhomogeneous multi-element compound foil. The foil is electrolyzed at different polishing rates for different elements by rapidly cycling between different current densities. During a first portion of each cycle at a first voltage a first element electrolyzes at a higher current density than a second element such that the material of the first element leaves the anode foil at a faster rate than the second element and creates a solid surface film, and such that the solid surface film is removed at a faster rate than the first element leaves the anode foil. During a second portion of each cycle at a second voltage the second element electrolyzes at a higher current density than the first element, and the material of the second element leaves the anode foil at a faster rate than the first element and creates a solid surface film, and the solid surface film is removed at a slower rate than the second element leaves the foil.

Abstract: A process and apparatus for quantitatively and selectively separating metal ions from mixtures thereof in aqueous solution. The apparatus includes, in combination, a horizontal electrochemical flow cell containing flow bulk electrolyte solution and an aqueous, metal ion-containing solution, the cell containing a metal mesh working electrode, a counter electrode positioned downstream from the working electrode, an independent variable power supply/potentiostat positioned outside of the flow cell and connected to the electrodes, and optionally a detector such as a chromatographic detector, positioned outside the flow cell. This apparatus and its operation has significant application where trace amounts of metal ions are to be separated.

Abstract: A process for the synthesis of fluorinated organic compounds and a reagent suitable for use in the process. The process is carried out by exchange with fluorides, while preferably agitating the reaction medium with ultrasonic sound.

Abstract: To detect bands in an electrophoresis capillary tube having a liquid separating medium, a light source and a light detector of a monitor are positioned on opposite sides of the capillary tube with the light source transmitting light through a first slit and light passing to the detector through a second slit after it has passed through the capillary tube. The first and second slits are aligned with the direction of motion of bands, have a maximum length of less than 500 micrometers and a maximum width of less than 200 micrometers. There are no vertical lengths in the capillary tube having a dimension greater than one third of its length between a sample injecting end and a detecting end of the capillary tube.

Abstract: Coating composition containing a resin and fine particles of an electrically semiconductive substance, whereby a coating film to be formed therefrom on a work article surface exhibits a varistor property represented by the following equation (1):I=(V/V.sub.1).sup.n (1)wherein I is a current density (mA/cm.sup.2); V.sub.1 is a voltage at which a current of 1 mA begins to flow when a voltage applied to the coating film is increased; V is an applied voltage; and n is an exponent showing the non-linearity between I and V and is 1.5 or more. Coating films formed from such coating composition exhibit excellent film forming and corrosion-resistant properties.

Abstract: The present invention is a method for enhancing the separation of polynucleotides or polypeptides of various chain lengths or a mixture of polynucleotides and polypeptides of various chain lengths using electrophoretic processes to sharpen sample component zones and produce maximum resolution of electrophoretically separated macromolecules by modifying the matrix of electrophoretic gel.

Abstract: An apparatus for physical-vapor deposition of material layers includes a distributed electron cyclotron resonance (ECR) plasma processing device (12) having a process chamber (14) and a plasma formation region (18). A magnetron target stage (19) connects to a sputtering target material (20) in fluid communication with the process chamber (14) and with the plasma formation region (18) and substantially within the line of sight or view angle of a semiconductor substrate (16). The magnetron target stage (19) induces particles to separate from the sputtering target material (20) and move into the process chamber (14) for subsequent deposition onto the semiconductor substrate (16).

Abstract: An electrolytic electrode substrate comprises an electrically conductive substrate and, formed on the surface of the electrically conductive substrate, an oxide layer having a thickness of from 10 to 200 .mu.m, wherein the oxide in the oxide layer comprises a non-stoichiometric composition containing oxygen and at least one metal selected from the group consisting of titanium, tantalum, and niobium. An advantage of the electrode substrate is that it is stable when used in electrolytic processes involving a reversal of current flow. Further, the electrode substrate is stable in the presence of corrosive substances such as a fluorine.

Abstract: A thin film forming apparatus which utilizes cluster ion beam deposition to form thin films on a substrate. In one embodiment, the electrons which ionize the vapor clusters are generated by a cathode which is located inside the corresponding anode. The cathode serves not only as a source of electrodes but also as a means for heating the crucible containing the substance to be deposited. In another embodiment, an electron emitter located at a position remote from the vapor flow in the apparatus is utilized as the source of electrons to form the ionized clusters.

Abstract: A ceramics rotatable magnetron sputtering cathode target comprising a cylindrical target holder and a ceramics layer as a target to be sputtered, formed on the outer surface of the target holder, wherein at least one layer selected from the group consisting of a layer of a metal or alloy having a thermal expansion coefficient of an intermediate level between the thermal expansion coefficients of the ceramics layer and the target holder, and a layer of a metal or alloy having a thermal expansion coefficient approximating to the thermal expansion coefficient of the ceramics layer, is formed as an undercoat between the ceramics layer and the target holder.

Abstract: A biosensor for electrochemically detecting an electrochemically active material generated by a reaction of a compound to be analyzed in a liquid sample and at least one compound which specifically reacts with the compound to be analyzed, in which a working electrode has at least two electrode parts and the supplied liquid sample contacts the electrode parts successively at an interval, and with which, the electrochemically active material and the compound to be analyzed are quantitatively analyzed separately.

Abstract: An electrochemical sensor for the determination of the partial pressure of oxygen in a bloodstream comprising a cathode and an anode immersed in an electrolyte contained in a chamber defined by an oxygen gas permeable membrane wherein the insulated portion of each of the conductors forming the cathode and the anode has an additional layer of insulation applied over the original insulation.

Abstract: A pH electrode suitable for in vivo use is provided in a cannula 10, and comprises a reference electrode 14 consisting of a chloridized silver wire surrounded by a solid unbuffered internal reference material 16 comprising potassium chloride, silver chloride, citric acid and sorbitol as a hygroscopic agent. The material 16 is surrounded by a PVC sleeve 12. The tip of the cannula 10 has a pH sensitive polymer-based membrane 20 across its end. The reference material has a pH when hydrated of about 2 which is below the range of pH response of the membrane 20.

Abstract: Inhibiting coke formation on heat transfer surfaces used to heat or cool a petroleum feedstock at coke-forming conditions. The heat transfer surfaces are treated with an effective amount of S,S,S-trihydrocarbyl phosphorotrithioate to inhibit coke formation on the heat transfer surfaces. The phosphorotrithioate is essentially free from contributing to corrosion and from producing catalyst-impairing by-products.

Abstract: A two stage process for catalytically reforming a gasoline boiling range hydrocarbonaceous feedstock. The reforming is conducted in two stages wherein the first stage is operated in a fixed-bed mode, and the second stage is operated in a moving-bed continual catalyst regeneration mode. A gaseous stream comprised of hydrogen and predominantly C.sub.4.sup.-- hydrocarbon gases are separated between stages. A portion of the hydrogen-rich gaseous stream is recycled and the remaining portion along with the C.sub.5.sup.+ stream are sent to second stage reforming.

Abstract: A novel zeolite characterized by a large number of secondary pores, a substantially decreased lattice constant, and a substantially decreased acid site density is attained by hydrothermal and acid-treating of an ultrastable Y-zeolite or a superultrastable Y-zeolite.

Abstract: Reactive S (e.g. H.sub.2 S and mercaptans) in petroleum liquid are scavenged by the use of oil soluble trialkyl hexahydro triazines wherein at least one alkyl group, and preferably all three, contain from 7 to 20 carbon atoms.

Abstract: A continuous process for deasphalting and demetallating a residue from crude oil distillation, by means of dimethyl carbonate as extraction solvent, comprises:mixing a residue from crude oil distillation with a recycled liquid stream containing oil and dimethyl carbonate, in order to produce a homogeneous solution;cooling said homogeneous solution and separating a refined light, liquid, phase; an extracted middle phase; and a heavy phase containing asphaltenes;recovering a primary, deasphalted/demetallated oil from said light phase;partially recycling said middle phase to the mixing step, and recovering a secondary deasphalted oil from the residual fraction;recovering asphaltenes from said heavy phase.

Abstract: Filtering systems used to filter contaminated fluid. The filtering system (10) includes a supply pump (12); a filter tank (14) having a plurality of removable filter cassettes (16) disposed therein, each filter cassette housing in proper orientation a filter pad (164); a suction pump (18); a level control mechanism (148) maintaining a substantially uniform level of contaminated fluid within the filter tank; and a control panel (20) housing other process control components. Operation of the filtering system includes a backflush cycle and a relaxation cycle to extend the loading life of the filter pads. Also included is a preventive measure designed to eliminate fluid shear that may result as the filter pads approach the end of their loading life. The double-density filtering system (300) employs double-density filter cassettes(304), each cassette housing a pair of filter pads (164). This allows the volume of the filter tank (302) to be reduced, thereby reducing turnover.

Abstract: A method of control of the porosity of wells with a fibrous fluid blocking layer disposed on formation faces is provided. By means of mineral fiber pellets of critical dimensions wherein the mineral fibers are highly soluble in acid, a fluid blocking layer formed of semi-dispersed pellets can bridge formation face pores subject to removal at will by acid treatment. Thus after well rework the plugging layer is treated by an acid solution after sealing the formation faces to prevent fluid losses to quickly dissolve the mineral fibers to the desired extent for control the porosity. A novel well workover product making the method possible is formed from raw material clinkers of highly acid soluble mineral fibers of between 5 to 15 microns in diameter by grinding in a hammermill into pellets of a range of 1/32 inch to 1/2 inch in diameter with an average being between 1/16 inch to 1/8 inch and with fiber lengths between 1/64 inch to 3/8 inch.