Abstract: A combustion grate has fire bars which have whole or partial cooling by gas or fluid use via a closed regulating circuit. Lines which conduct the fluid or gas have thermal expansion capability. In particular, windings are provided in the shape of a helical spring. The fire bars have corrugated exchangers and can be replaceable rods.

Abstract: A modular pontoon boat including a modular deck and modular pontoons is described. The modular deck includes interlocking portions. Each modular pontoon includes interlocking sections having locks and keys. The modular pontoon boat enables the length of the boat to be selected at the time of assembly, rather than fabrication.

Abstract: A process for growing a single crystal silicon ingot having an axially symmetric region substantially free of agglomerated intrinsic point defects. The ingot is grown generally in accordance with the Czochralski method; however, the manner by which the ingot is cooled from the temperature of solidification to a temperature which is in excess of about 900° C. is controlled to allow for the diffusion of intrinsic point defects, such that agglomerated defects do not form in this axially symmetric region. Accordingly, the ratio v/G0 is allowed to vary axially within this region, due to changes in v or G0, between a minimum and maximum value by at least 5%.

Abstract: A SiGe monocrystalline etch-stop material system on a monocrystalline silicon substrate. The etch-stop material system can vary in exact composition, but is a doped or undoped Si1−xGex alloy with x generally between 0.2 and 0.5. Across its thickness, the etch-stop material itself is uniform in composition. The etch stop is used for micromachining by aqueous anisotropic etchants of silicon such as potassium hydroxide, sodium hydroxide, lithium hydroxide, ethylenediamine/pyrocatechol/pyrazine (EDP), TMAH, and hydrazine. For example, a cantilever can be made of this etch-stop material system, then released from its substrate and surrounding material, i.e., “micromachined”, by exposure to one of these etchants. These solutions generally etch any silicon containing less than 7×1019 cm−3 of boron or undoped Si1−xGex alloys with x less than approximately 18. Alloying silicon with moderate concentrations of germanium leads to excellent etch selectivities, i.e.

Abstract: Plasma enhanced chemical vapor deposition (PECVD) reactors and methods of effecting the same are described. In accordance with a preferred implementation, a reaction chamber includes first and second electrodes operably associated therewith. A single RF power generator is connected to an RF power splitter which splits the RF power and applies the split power to both the first and second electrodes. Preferably, power which is applied to both electrodes is in accordance with a power ratio as between electrodes which is other than a 1:1 ratio. In accordance with one preferred aspect, the reaction chamber comprises part of a parallel plate PECVD system. In accordance with another preferred aspect, the reaction chamber comprises part of an inductive coil PECVD system. The power ratio is preferably adjustable and can be varied. One manner of effecting a power ratio adjustment is to vary respective electrode surface areas.

Abstract: A processing apparatus of the present invention has a mounted chamber holding a semiconductor wafer and having members for work-processing the substrate under any of heating, plasma and process gas or a combination of them, in which a film of Al2O3 and Y2O3 is formed on an inner wall surface of the chamber and on those exposed surface of the members within the chamber and has a high-corrosion resistance and insulating property and, when the process gas is introduced onto a processing surface of a semiconductor wafer and diffused into it, any product is less liable to be deposited on a plasma generation area and on those members held within the chamber.

Abstract: For increasing the rate with which a workpiece is treated in a plasma enhanced chemical vapor deposition method and thereby lowering for coating treatment exposure of the coating to ion impact, there is maintained a non-vanishing dust particle density along the surface to be treated with a predetermined density distribution along this surface. The density distribution may be controlled by appropriately applying a field of force substantially in parallelism to the surface to be treated and acting on the dust particles entrapped in the plasma discharge.

Abstract: A water heater including a water container; a combustion chamber containing a main burner and a pilot burner positioned to heat water in the water container and having a side wall; a main burner fuel supply line adapted to connect between a fuel control valve and a main burner; a pilot fuel supply line adapted to connect between the fuel control valve and a pilot burner; a heat sensor line connected to a heat sensor and adapted to connect to the fuel control valve and positioned to sense heat from the pilot burner; an igniter line connected to an igniter positioned proximate the pilot burner and connected to an igniter initiator; and a removable plate sealed to the combustion chamber through which the main burner fuel supply line, the pilot fuel supply line, the heat sensor line and the igniter line pass in a sealed condition.

Abstract: A water heater including a water container; a combustion chamber containing a main burner and a pilot burner positioned to heat water in the water container and having a side wall; a main burner fuel supply line adapted to connect between a fuel control valve and a main burner; a pilot fuel supply line adapted to connect between the fuel control valve and a pilot burner; a heat sensor line connected to a heat sensor and adapted to connect to the fuel control valve and positioned to sense heat from the pilot burner; an igniter line connected to an igniter positioned proximate the pilot burner and connected to an igniter initiator; and a removable plate sealed to the combustion chamber through which the main burner fuel supply line, the pilot fuel supply line, the heat sensor line and the igniter line pass in a sealed condition.

Abstract: A self-compensating, energy saving heat transfer unit to provide an efficient means to transfer energy from steam to water in a central heating system. The steam enters a mixing chamber and creates a negative pressure environment. Water in a backwater pipe, which is at a lower temperature and pressure, is than is absorbed into the mixing chamber where energy is passed from the steam to the water. The water then leaves the first mixing chamber and enters a second mixing chamber where compensation water is added to make up for the possible loss of water that may occur in the central heating system. The heated water then exits the heat transfer unit and goes back into the central heating system. After being cooled in the central heating system, the water then reenters the heat transfer unit at the backwater pipe and continues the cycle over again.

Abstract: A hydrogen generating system is provided for use in internal combustion engines for increasing the efficiency of the engine and decreasing emissions from the engine. The hydrogen generating system has an electrolysis cell for generating hydrogen and oxygen gases by electrolysis of an aqueous solution, a power source for providing electrical power to the electrolysis cell, an outlet flow means for introducing the generated gases into the intake manifold system of an internal combustion engine, a monitoring means for monitoring the operating conditions of the hydrogen generating system, and a control means connected to the monitoring means for controlling the operation of the hydrogen generating system in response to the monitoring means. The invention is also directed to a controller for controlling a hydrogen generating system for use in an internal combustion engine for increasing the efficiency of the engine and decreasing emissions from the engine.

Abstract: A valve-open-close mechanism is proposed which has parts designed to reduce friction during sliding. The electromagnetic actuator comprises a pair of electromagnets each having a stator and a coil opposed to each other with a gap therebetween, an armature disposed in the gap, and a first stem for transmitting to external the movement of said armature. A retainer and a first return spring are provided on the valve. A second stem is provided at other side of the armature and another retainer and a second return spring are provided for the second stem. A coating film is formed on at least one of the surface or end face of the stem portion of the valve, end faces of the first return spring or second return spring, spring bearing end faces of the retainers, surface or end face of the second stem, and the surface of the armature.

Abstract: Provided is a diamond-coated sliding part that is light, has excellent abrasion resistance, that prevents abrasion of the material of an opposite member, and that is effective in reducing power loss. This sliding part is especially useful as an adjusting shim for the valve train mechanism of an internal combustion engine such as an automobile engine in which the base material is silicon nitride or sialon and this base material surface is coated with a diamond coating layer. By performing finish processing on only a small part of peaks of diamond particles protruding from the surface of the diamond coating layer to reduce the height of the protrusions, or by controlling film forming conditions, etc., the profile bearing length ratio (tp) at a cutting level of 0.1 &mgr;m for the sliding surface of the diamond coating layer is made 60% or greater.

Abstract: A chain drive of a V-engine with overhead camshafts includes chains which are driven by a crankshaft. In each case the overhead cam shafts are driven by a separate chain. Tensioner blades swivellably assigned to a respective slack run of the chains are acted upon by hydraulic chain tensioners of the same type of construction. The chain tensioners are arranged in an accessible manner on the exterior side on the V-engine and interact with sloped contact ramps on the tensioner blades. The chain tensioners of the same construction are arranged transversely to one another on the V-engine and are configured for a reliable venting in each installed position by including two mutually independently operating leakage devices.

Abstract: A stratified charge is formed in an engine by injecting fuel at an impingement surface adjacent an outlet of the injector. The injected fuel thereby forms a cloud shallowly penetrating the combustion chamber so as to float therein to reduce wall-wetting and subsequent soot formation. A substantially flat top piston urges the cloud upwardly during a compression stroke of the engine. The cloud remains substantially unmixed with the inducted air, thereby producing the stratified charge. The continued motion of the piston causes the cloud to move toward the spark plug for ignition.

Abstract: Several embodiments of direct injected spark ignited internal combustion engines. In these embodiments, the fuel injector is positioned quite close to the cylinder bore axis so as to ensure a homogeneous mixture in the combustion chamber under all running conditions and particularly high speed high load conditions. The injector in each embodiment is positioned, however, relative to this spark plug or plugs so that fuel will not be sprayed into their gap to cause fouling. In addition, an improved arrangement for showing heat transfer from both the spark plugs and fuel injectors to the engine coolant is also disclosed.

Abstract: In a pressure-maintaining device for a fuel supply system of an internal combustion engine (1) of a motor vehicle, a pressure reservoir (5) is arranged in a supply line (7) leading to the internal combustion engine (1). The pressure reservoir (5) has a pressure chamber (13), which is bounded by a movable wall (14) that is pretensioned by a compression spring (15). The position of the movable wall (14) is registered by a displacement transducer (18) and forwarded to a regulating device (12). The regulating device (12) regulates the rotational speed of a fuel pump (3) as a function of the position of the movable wall (14).

Abstract: In a system for coating human skin, a chemical composition, such as a cosmetic or medical formulation, is uniformly coated over the entire body or selected parts of the body of the person being coated. The system includes atomization of the coating composition, containment of the atomized spray, and residual recovery which together yield a novel method for applying chemical compositions.

Abstract: The present invention relates to an apparatus for mixing a solid or liquid chemical into water for solving for preparing a chemical solution. The present apparatus is used for preparing a chemical solution, attached to a channel for solving chemical into water running along the channel., The apparatus is provided with a container having an inlet for introducing water, an outlet for discharging the water introduced from the inlet, a water path extending from the inlet to the outlet, and a chemical room for housing the chemical. According to the present invention, the chemicals housed in the chemical room is solved into water running through the water path. Chemical may be solved easily and safety.

Abstract: An energy saving heat transfer unit providing an efficient means to transfer energy from steam to water in a central heating system. The steam enters a mixing chamber and creates a negative pressure environment. Water in a backwater pipe, which is at a lower temperature and pressure, is than is absorbed into the mixing chamber where energy is passed from the steam to the water. The heated water then exits the heat transfer unit and goes back into the heating system. After being cooled in the heating system, the water then reenters the heat transfer unit at the backwater pipe and continues the cycle over again.

Abstract: A flood control device bases a valve closure decision on a plurality of sensed parameters. The parameters may be sensed by both a mechanical and an acoustic flow sensor. An adaptive parameter evaluation algorithm and fuzzy logic decision making may be used to reduce errors in triggering flow shut-off.

Abstract: An on-off device disposed at each of the inlet and the outlet of a fluid controller is one of five kinds of on-off devices, i.e., on-off device having a two-port valve, on-off device having a two-port valve and a three-port valve, on-off device having a two-port valve and two three-port valves, on-off device having two three-port valves, and on-off device having three three-port valves. The main bodies of two-port valves of all types of on-off devices are identical in configuration and each have an inlet and an outlet in a bottom face thereof. Main bodies of three-port valves of all types of on-off devices are identical in configuration and each formed in a bottom face thereof with an inlet, an outlet always in communication with the inlet, and an inlet-outlet subopening.

Abstract: A valve arrangement for controlling hydraulic fluid flow to a subsea system includes a plurality of docking modules each having a valve element for controlling the flow of a fluid and a docking module port for fluid flow between the valve element. The valve arrangement additionally includes a manifold having manifold ports of uniform cross section. The docking modules can be interchangeably mounted to the manifold ports as desired to tailor the valve arrangement for any selected valve operation.

Abstract: A modular fluid control system is disclosed in which a common fluid manifold is formed by the connection of a required number of identical manifold modules (4). Each manifold module (4) has a valve module (9) connected thereto with connections to receive and return fluid from/to the manifold. In addition, each manifold module (4) includes data/power connectors (36, 37) which allow connection to adjacent manifold modules (4) thereby forming a common power and data bus through the connected manifold modules (4). Each manifold module (4) includes a controller (18) capable of controlling the valve within its connected valve module (9) in accordance with instructions received from a primary controller (16) connected to the data/power bus at one end of the common manifold.

Abstract: A gas chromatograph with multiple valves is disclosed. An embodiment of the multi-valve gas chromatograph includes multiple valves, multiple thermal conductivity detectors (TCD's), and a manifold. This allows separation and measurement of a gas sample in one compact integrated unit. The unit is particularly desirable because the solenoids associated with the valves are attached directly to the underneath of the manifold, thus eliminating the need for tubing between the solenoids and the valves.

Abstract: A unitary, self-contained apparatus for generating microbubbles using a pipe section with a constriction device for producing a venturi effect to cause a mainstream liquid flowing under pressure in the pipe section to draw a column of additive fluid into the mainstream liquid from an aspiration tube for mixing with the liquid and a turbulence part of the pipe section immediately downstream from the constriction device. Protrusions from the inside surface of the turbulence part of the pipe section protrude to at least the theoretical interface between the column of additive fluid and the surrounding mainstream liquid and preferably beyond, where the theoretical interface is a circumference of the column of additive fluid having a radius equal to the radius of the inside surface of the aspiration tube.

Abstract: End or tab stock and a method for its manufacture in which a low alloy content aluminum alloy is continuously cast to form a hot feedstock, the hot feedstock is rapidly annealed and quenched rapidly to prevent substantial precipitation of alloying elements and rolled. The can end and tab stock of the invention has strength and formability equal to higher alloy content aluminum alloy.

Abstract: A ferritic stainless steel plate of excellent ridging resistance and formability, as well as a manufacturing method thereof are proposed. Specifically, the rolling is conducted at a rolling reduction of 30% or more in at least 1 pass and at a temperature difference between the center of the plate thickness and the surface of 200° C. or lower in a pass for the maximum rolling reduction to cause the area ratio of a {111}orientation colony to be present by 30% or more in the regions of ⅛ to ⅜ and ⅝ to ⅞ of the plate thickness. The {111}orientation colony is an assembly of adjacent crystals in which the angle of <111> orientation vector for each of the crystals relative to the direction vector vertical to the rolling surface is within 15°.

Abstract: Provided is a method for preparing a flowable solid propellant wherein a) liquid oxidizer is added to a tank, b) pellets of cross-linked hydrogel polymer are added to the liquid oxidizer in the tank so that liquid oxidizer is absorbed into the pellets to form flowable combustible pellets and c) the combustible pellets are then flowed into a combustion chamber of a vehicle to combust and the combustion products flow out the propulsion nozzle of the vehicle. Also provided are the liquid oxidizer absorbed flowable combustible pellets so made.

Abstract: A propellent charge powder for barrel-type weapons having a plasticizer on the basis of nitramine and nitrocellulose, nitramine and energetic and non-energetic plastic binders, or nitrocellulose or an explosive, and wherein the plasticizer is a mixture of at least two chemically different dinitro diaza compounds. The plasticizer facilitates the production and use of the propellent charge powder possessing a low temperature coefficient.

Abstract: An electronic component connecting method of connecting a first electronic component and a second electronic component via a connecting structure like a bump electrode in which a thermosetting conductive adhesive is applied on connecting electrodes on an IC chip, which serves as the first electronic component, by printing or the like, and is hardened, whereby tapered projecting electrodes as bump electrodes are formed to project in the form of, for example, a circular cone. Then, a conductive adhesive for connection is applied on the projecting electrodes. Before the conductive adhesive for connection is hardened, the IC chip is aligned with a wiring board, which serves as the second electronic component, so that the ends of the projecting electrodes and connecting electrodes on the wiring board are in contact with each other. In this aligned state, the conductive adhesive for connection is hardened.

Abstract: The invention relates to a radiopaque catheter tip and catheter assembly having radiopaque elements associated with a catheter. The preferred materials for the radiopaque elements are made of a 90% platinum and 10% nickel composite structure or a 90% platinum and 10% iridium composite structure.

Abstract: A support 55 comprises a dielectric 60 covering a primary electrode 70, the dielectric 60 having a surface 75 adapted to receive a substrate 25 and a conduit 160 that extends through the dielectric 60. The thickness of a portion of the dielectric 60 between an edge 195 of the primary electrode 70 and a surface 180 of the conduit 160 is sufficiently large to reduce the incidence of plasma formation in the conduit 160 when the primary electrode 70 is charged by an RF voltage to form a plasma of gas in the chamber 30 during processing of the substrate 25.

Abstract: A liquid processing apparatus is capable of uniformly processing substrates by a liquid process. The liquid processing apparatus has a chemical liquid tank (21) containing a processing liquid for processing wafers (W) by a predetermined liquid process, a carrying device (24) provided with a wafer holder (42) capable of holding a plurality of wafers (W) to be subjected to the liquid process in a vertical position, and capable of carrying the wafers (W) between a processing position where the wafers (W) are immersed in the chemical liquid contained in the chemical liquid tank (21) and a position above the processing position, and a cover (50) for covering a space extending over the wafers (W) held on the wafer holder (42) of the carrying device (24) so that any air currents may not be substantially generated in the same space.

Abstract: There is disclosed a non-contact radiating structure provided with a plurality of space portions formed by a boundary wall. In the space portion a heating source and a heat pipe are installed in the vicinity of each other. Since the heating source and heat pipe in the same space portion are prevented by the boundary wall from being influenced by another heating source, each heat pipe efficiently transmits heat generated by the heating source. The radiating structure is installed in a housing installed outdoors. The heat pipe reaches the housing, and the heat is radiated to outside air from a housing outer surface.

Abstract: An air compressor and aftercooler combination in which the aftercooler is located in front of the air compressor. The aftercooler is connected to the air compressor for receiving hot, high pressure air and for effectively cooling the same such that the temperature of the high pressure air delivered by the aftercooler approaches that of atmospheric ambient. A fan is located to draw and direct atmospheric ambient air to the compressor and to and through aftercooler for effective cooling of the high pressure air in the aftercooler, as received from the compressor.

Abstract: A heat exchanger and a method of manufacturing the heat exchanger is disclosed for dissipating heat from a heat generating component. The heat exchanger comprises a thermally conductive base in thermal communication with the component, a plurality of thermally conductive plate fins affixed to the base wherein the plate fins define a fin field and channels, and fluid control for controlling the fluid flow within the fin field. The individual fins of the heat exchanger are tapered with the cross-sectional area of the individual fins decreasing from an inlet region of the heat exchanger toward a middle region of the heat exchanger. The tapering of the fins function to minimize formation of high pressure with the fin field. In an alternative embodiment, the heat exchanger may comprise an aperture for enhancing ventilation of fluid within the fin field, and thereby reducing formation of high pressure within the fin field.

Abstract: A heat exchanger and a method of manufacturing the heat exchanger is disclosed for dissipating heat from a heat generating component. The heat exchanger comprises a thermally conductive base in thermal communication with the component, a plurality of thermally conductive plate fins affixed to the base wherein the plate fins define a fin field and channels, and fluid control for controlling the fluid flow within the fin field. The individual fins of the heat exchanger comprise apertures extending through the walls of the individual fins. The formation of the apertures within the individual plate fins provides communication of fluid across the channels within the fin field.

Abstract: A heat exchanger and a method of manufacturing the heat exchanger is disclosed for dissipating heat from a heat generating component. The heat exchanger comprises a thermally conductive base in thermal communication with the component, a plurality of thermally conductive plate fins affixed to the base wherein the plate fins define a fin field and channels, and fluid control for controlling the fluid flow within the fin field. The individual fins of the heat exchanger comprise textured regions positioned about a side surface of the fins and extending into an adjacent channel. The positioning of the textured regions function to minimize formation of high pressure within the fin field by disturbing the fluid flow passing along the fins. Alternatively or in conjunction with the above-outlined embodiments, the heat exchanger may comprise a fluid control feature for substantially preventing premature egress of fluid from a top region of the fin field caused by the high pressure region within the fin field.

Abstract: The invention relates to a cooling apparatus (10) based on heat energy bound to working fluid in phase transition, the cooling apparatus comprising, for conducting elsewhere the heat energy generated by an electronic component (7), elongated cooling elements (1; 6a, 6b; 9a-9f) containing working fluid and extending in at least two different directions forming a matrix of cooling elements, and a heat conducting material (8; 15) binding the matrix of the cooling elements. The cooling elements (6a, 6b; 9a-9f) are arranged parallel to a circuit board level (A) and in at least one direction deviating from the circuit board level (A).

Abstract: A torsion bar clamp device and method for mounting a heat sink to an electronic component comprising a torsion bar having a longitudinally extending bar and at least one integral lever adapted to engage a heat sink and mounting legs which couple forces imparted by the torsion bar to the heat sink and electronic component such that the heat sink and electronic component are compressively coupled. The invention may be manufactured of injection molded plastic and may be adapted to allow the mounting legs to engage bosses on a socket in which an electronic component is mounted.

Abstract: An apparatus for cleaning tubing in an operating heater, in which the tubing has an inlet and an outlet. While the heater is in operation, a pig is run through the tubing from the inlet to the outlet and then returned to the inlet along return tubing, in parallel connection to the heater tubing. A combined pig launcher and receiver mounted parallel to the tubing, and controlled with three-way full port valves, is used to launch pigs into the tubing and remove them from the tubing. A boost pump is used to force pigs back from outlet to inlet.

Abstract: A structure of a super-thin heat plate comprising surrounding bodies having a thin plate shape and supporting body is disclosed. Each supporting body have function of capillarity and is enclosed within the surrounding bodies. The surrounding bodies and the supporting body are connected by a plurality of welding spots, and the edges are properly sealed. The supporting body is distributed uniformly by a whole web structure. Thus, the heat plate wick structure is very stable with a preferred performance of heat transfer and can be finished easily. In mass production, the structure still has a high stability.

Abstract: In a heat exchanger of the present invention for exchanging heat between fluid flowing in a flow passage in a heat exchanger tube and fluid flowing outside of said heat exchanger tube, a solid bar-like insertion member or a hollow bar-like insertion member whose opposite ends are closed is provided in said flow passage in which a fluid having phase change flows in gas-liquid two phase state or liquid phase state, a cross section of said insertion member is formed into a substantially circle shape, a polygonal shape or a starlike shape, and a cross-sectional area of a flow passage in which said fluid flows is reduced as a mass flow rate quality of said fluid is reduced. With this construction, it is possible to restrain the pressure loss at the time of evaporation, and the evaporation ability can be enhanced or can be restrained from being deteriorated.

Abstract: The invention relates to a flat tube evaporator for motor vehicle air conditioning equipments with flat tubes (2), the longitudinal extension direction of which is vertical, and zig zag fins (8) arranged between the flat tubes (2), against which the external heat exchange fluid can flow (arrow 9). According to the invention it is provided that a water flow gutter (50) extending downwards on both sides of the flat tubes (2) is designed next to the rear end region (52) of the zig zag fins (8), seen in the flow direction (arrow 9) of the external heat exchange fluid.

Abstract: Refrigerant fluid such as CO2, compressed to the supercritical pressure by a compressor, is delivered selectively through a three-way valve, either into a branch of the circuit containing a cooler, an expansion device and an evaporator for cooling the cabin of a vehicle, or into a branch containing another expansion device and a heat exchanger for the purpose of heating the cabin.

Abstract: A transmission fluid cooling system includes a cooler-bypass unit having a banjo bolt relief valve. The banjo bolt relief valve includes a head portion and a body portion. A relief valve is incorporated into the body portion. A valve seat is formed between the head portion and body portion. A ball is biased against the valve seat toward the head portion by a spring within the body portion. When the transmission fluid is cool and viscous, pressure buildup in the head portion overcomes the spring bias of the ball against the valve seat, permitting the flow of transmission fluid through the cooler-bypass unit, bypassing the transmission fluid cooling unit.

Abstract: An integral well filter and screen and a method for making and using it are described. A first embodiment includes a perforated cylindrical well screen with a filter assembly in its interior. The filter assembly includes a pliable filter material bonded to a filter support. The filter support is a plastic lattice rigid enough to hold the shape of the filter assembly and keep the filter material in contact with the inner surface of the well screen, yet deformable enough that the filter assembly can be formed into a shape consistent with the interior of the well screen. A second embodiment includes a well screen with a filter made of a rigid, porous material placed inside the well screen. Because the filter is rigid, it needs no filter support. Methods of manufacturing each of the embodiments are presented.

Abstract: It is common practice to rotate casing in shallow holes (to approx. 1000m). This has been found to noticeably enhance the bond between the casing and cement and wellbore wall and cement and to decrease the chance of microchannelling along the annulus. The rotating casing assembly and method, as described herein, allows for rotation of the casing at any depth. Only the lower portion is rotated. This lower portion is generally that portion crossing the production zone. This method is extremely economical compared to other methods and requires no additional rig time or surface equipment. The casing is driven to rotate by the energy of the fluid being pumped through the casing and across vanes in the casing.

Abstract: A method of fracturing a subterranean formation which surrounds a well bore comprises the steps of providing a fracturing fluid, and injecting the fracturing fluid into the well bore at a pressure sufficient to form fractures in the subterranean formation which surrounds the well bore. The pressure is then released from the fracturing fluid, after which the fluid may be removed from the well and the well placed into production. The fracturing fluid comprises an aqueous liquid, a polysaccharide soluble or dispersible in the aqueous liquid in an amount sufficient to increase the viscosity of the aqueous liquid, an enzyme breaker which degrades said polysaccharide at a temperature above 180° F. Fracturing fluid compositions and enzyme breaker systems useful for carrying out the invention are also disclosed.