Abstract: A nebulizer for efficiently and reliably delivering aerosolized fluid to an inhaling patient is disclosed. The nebulizer includes a fixed diverter and a movable fluid orifice or fluid pathway connected with an actuator for responding to an inhalation or a manual actuation and beginning the nebulization process. Also provided is a method of providing nebulization including the steps of moving a fluid orifice or fluid pathway connected to an actuator so that the fluid orifice or fluid pathway reaches a nebulizing position during inhalation.

Abstract: The present invention relates to an inhaler for effectively delivering medications by inhalation through the mouth of patients, having a spacer for more effectively mixing the medication and air, and easy to operate lever and canister selection mechanisms. A preferred embodiment of the invention has a mouthpiece comprising a flexible, elastic material. A lever arm is provided that is opposed to the body of the inhaler, which allows a patient to use the entire hand to activate the metered dose inhaler canister. In a preferred embodiment a valve assembly and whistle are included in the inhaler to improve the consistency and effectiveness of delivery of medication to the lungs of a patient.

Abstract: The present invention is an inner pressure indicator of a cuff comprising, a housing possessing on one end an opening that can connect to a cuff inflating tube of a tracheostomy tube with a cuff or of an endotracheal tube and on the other end of said housing possessing an opening to which a valve that prevents the reduction of inner pressure is equipped with, said housing is characterized by being equipped with an inner pressure indicating device of cuff and also the inner pressure of the cuff can be regulated by said opening with a valve by way of said inner pressure indicating device of the cuff.

Abstract: Method and apparatus for enabling a user having reduced manual dexterity and/or strength to operate an aerosol inhaler by modifying the inhaler to have a lever juxtaposed adjacent the flat end of the aerosol cannister, or inserting an inhaler into a device having a lever juxtaposed to the flat end of the aerosol cannister, the lever adapted to be moved by the user to depress the aerosol cannister and dispense medication contained in said aerosol cannister.

Abstract: A device for passive humidification of tracheostomized or intubated patients, comprising an outer body which forms an opening for connection to the patient and is connected to at least one seat of a filtering element which is connected to the outside, the device further comprising, on the outer body, a coupling for connection to at least one oxygen delivery duct which ends proximate to the outer part of the filtering element.

Abstract: HEAD PROTECTION EQUIPMENT THAT CAN BE DONNED QUICKLY The breathing protection equipment comprises a breathing mask provided with a regulator for connection to a source of breathing gas under pressure, and a harness having at least one extensible strap whose ends are connected to the mask and which comprises an element that can be inflated temporarily by the gas under pressure in order to lengthen the strap until it is of a size that is sufficient to enable the user to put the harness over the head, and that can be exhausted to enable the strap to press the mask against the face. A flexible cover covering the head is fixed in leaktight manner to the single strap or to the top strap of the harness, and it is also fixed to the mask; it is transparent, at least in a portion facing the eyes when the equipment is being worn.

Abstract: Triplicate Diving Gas Valve Device, comprising: a siren unit, a Life Coat Inflation unit and a User's Respiration Unit. The Siren drives its alarm sounding by reciprocating pounding of piston in a cylinder, by reason of this, the siren will serve its purpose ready submerged in waters or on the surface. The Gas Valve can be used in combination with both the Life Coat and the Respiration Mouthpiece, it can be manipulated manually using one hand expeditiously for triplicate services including: Life Coat Inflation/Deflation, siren alarming appealing for Help, and Respiration-charged air-compression. At a suitable location in the Respiration Mouthpiece is positioned a Flow Division Block serving to block compressed gas that is supplied from the Compression Cylinder, so that the compressed gas is split to pass to flanks on both sides, in that manner safeguarded from charging straight into Diver's throat, so that the diver is relieved from any discomfort while breathing all the while.

Abstract: An anesthetic metering system includes an anesthetic reservoir (1) having an anesthetic reserve (2), which is limited by a flexible material wall and to which pressure is admitted by means of a propellant (3) acting thereon via the wall material. The anesthetic reservoir (1) has a first valve (4), which is in flow connection with the liquid anesthetic reserve (2) and can be inserted into a mounting element (6) of an anesthesia apparatus. The metered release of anesthetic to the anesthesia apparatus takes place via a volumetric nozzle (8). The present invention provides an anesthetic metering device which avoids, on the one hand, the drawbacks of the anesthetic evaporators used previously, which are to be refilled with anesthetics at the workplace, and makes possible the refilling of the anesthetic reservoir (1) at the anesthetic manufacturer, on the other hand.

Abstract: The invention provides an apparatus for supplying a respiratory gas to a respiratory air way of a patient. The respiratory gas supplying apparatus 10 includes a cylinder 12 filled with a respiratory gas, a cart 14 having an accommodating portion for disposing the cylinder 12, a shut-off valve 18 attached to the cylinder 12, a flow regulating valve 40 attached to the shut-off valve 18, a conduit 22, attached to the flow regulating valve 40, for directing the respiratory gas to the inlet of the respiratory airway of the patient, a coupler 16, integrally connected to the flow regulator 40, for coupling the flow regulating valve 40 to the shut-off valve 18, and a linkage 110 for disengaging the coupler 16 from the shut-off valve 18 when the cylinder 12 is detached from the cart 14.

Abstract: Mask ports 180 for attaching supplemental oxygen tubes 510 or measurement devices to a respiratory mask are downwardly directed and recessed into the base 110 of the mask frame 100. The ports may comprise a pair of downwardly extending tubular spigots 185 each housed in a respective recess 190 in the base 110, with a shallow bridge recess 290 therebetween for receiving a bridging piece 300 of a closure cap 280.

Abstract: A nasal cannula retainer has a flexible member and cannula grips. The flexible member has a central nose portion with an adhesive backing for adhering to a patients nose and two cheek portions connected to the nose portion, each of the cheek portions having an adhesive backing for adhering to a patient's cheek. The adhesive layers are covered with a peel layer which is removed prior to applying the retainer. The cannula grips are attached to the cheek portions to secure a nasal cannula on each of the patient's cheeks. The grips are releasable and reusable, allowing the cannula to be repositioned or temporarily removed without the need for the retainer to be discarded and replaced, and without the use of tape to secure the cannula to the retainer after the cannula is repositioned.

Abstract: A speaking valve for a tracheostomy tube which is disposed in the first end of the tube protruding from the throat of the patient. The valve has guiding ribs and a retainer to retain a ball within the end of the tube. The flow of air around the ball is unrestricted to reduce the force required to move the ball when the patient inhales and exhales. A spherical chamber is formed in which the ball is disposed. The tracheostomy tube with the valve in the first end presents a low profile.

Abstract: A method of treating snoring, includes injecting least one of a monomer composition, a polymer solution and a microparticle solution into a patient's soft palate, optionally with a least one of an additional medicament, bioactive agent, sclerotic agent or stiffening agent. The injected composition, if not already polymerized prior to injection, is allowed to polymerize to form a polymer within the soft palate, thereby stiffening the soft palate, rendering it resistant to palatal flutter.

Abstract: In a method of performing a hyaline cartilage allograft transplantation procedure in which a surgeon has pre-operatively determined a size of allograft to be needed for the procedure, a service provider facilitates the procedure by arranging, upon receiving an order from the surgeon or a hospital for an allograft of a specified diameter, for the delivery of a precut allograft core along with a customized set of instrumentation for performing the transplantation to the surgeon or hospital prior to the scheduled time of the operation. The service provider also arranges for the return of any non-disposable instrumentation to the service provider after the operation.

Abstract: The need for the delivery of insulin by injection can be reduced or eliminated by a method whereby an aerosolized insulin formulation is delivered to a patient's lungs and the rate at which the insulin is absorbed into the blood is increased by the use of an inhale-exhale breathing maneuver. Particles of insulin delivered to the surface of lung tissue will be absorbed into the circulatory system. The rate of absorption is enhanced by instructing the patient to inhale maximally and thereafter exhale maximally. This maneuver causes a spike in the rate at which insulin enters the circulatory system thereby increasing the rate at which glucose is removed from the circulatory system. The insulin may be a dry powder but is preferably in a liquid formulation delivered to the patient from a hand-held, self-contained device which automatically releases an aerosolized burst of formulation.

Abstract: The present invention is generally directed to smoking articles having reduced carbon monoxide delivery. In order to reduce carbon monoxide delivery, the wrapping papers used to construct the smoking article has a fiber basis weight of less than about 18 gsm. Smoking articles constructed in accordance with the present invention can have a carbon monoxide delivery less than about 18 mg per smoking article.

Abstract: A finger nail decorations attaching device includes a base member having a recess for receiving a finer therein and a strip driven by two mandrels is movably located above the base member, wherein a plurality of decals are connected to the strip. A heating member is located beside the strip and softens the decals. A pressing member has a rod and a soft pad which is connected to a first end of the rod and located above the strip. The rod is moved toward the strip by pivoting a lever connected to the rod.

Abstract: A transmission for changing rotary motion into angularly reciprocating motion and adapted to be mounted on the output end of a power unit of the type having a rotary drive output and used to drive a tool. The transmission is comprised of a support member, a driving resinous member supported by the support member for rotary motion, and a driven resinous member supported by the support member for reciprocating angular movement by the support member. The transmission subassembly is formed by the driving resinous member, driven resinous member and support member and adapted to be mounted on the output end of the power unit with a rotary drive output mechanically coupled to the driving resinous member. A driving cam surface is disposed on a portion of the driving resinous member. A driven cam surface is disposed on a portion of the driven resinous member. The driving cam surface is in contact with the driven cam surface during at least a portion of the cycle of rotation of the driving cam surface.

Abstract: The file, the body of which is provided on at least part of its surface with a roughness varying from 10 to 100 &mgr;m, is made of flat, pressed or hardened glass. The file can have a variety of geometrical shapes and cross sections.

Abstract: A hair warming tool of the present invention is in the form of sheet and has at least one heating part in the center thereof and a margin around said heating part. It is designed to wrap tied hair in said heating part and to be held in place to keep the wrapping state by fastening said margin by means of a fastening means such as an elastic band, a string or a wire. A hair treating method of the present invention comprises wrapping tied hair with a hair warming tool of sheet form having at least one heating part while leaving at least the part of the hair near the roots unwrapped to warm the hair.

Abstract: A device for holding a kit of items used for wet shaving has a razor-receiving section for storing a razor in an upright manner with the blade head protectively located, and a container-receiving section for storing a can of shaving foam or gel. The body of the holder has an internal storage space for storing one or more replacement blade cartridges, and a miniature mirror is removably and reversibly fitted in the base of the device.

Abstract: This application relates to a case (1) comprising a bottom (2) and a lid (4) capable, at least prior to first use, of pivoting with respect to the bottom so as to be positioned underneath the latter, the bottom (2) being hinged about a first axis (A1) with respect to an intermediate element (20), the latter being hinged with respect to the lid (4) about a second axis (A2), locking means (B1, B2, C) being capable of locking the lid (4) with respect to the intermediate element (20) when the latter pivots with respect to the bottom (2) about the axis (A1), and of locking the bottom (2) with respect to the intermediate element (20) when the latter pivots with respect to the lid (4) about the axis (A2).

Abstract: In an ultrasonic washing method of washing a thing to be washed by supplying ultrasonic-wave-applied cleaning fluid to the thing, the ultrasonic wave is applied to the cleaning fluid in such a manner that the ultrasonic wave is turned on and off repeatedly at specific time intervals.

Abstract: In a system for cleaning a workpiece or wafer, a boundary layer of heated liquid is formed on the workpiece surface. Ozone is provided around the workpiece. The ozone diffuses through the boundary layer and chemically reacts with contaminants on the workpiece surface. A jet of high velocity heated liquid is directed against the workpiece, to physically dislodge or remove a contaminant from the workpiece. The jet penetrates through the boundary layer at the point of impact. The boundary layer otherwise remains largely undisturbed. Preferably, the liquid includes water, and may also include a chemical. Steam may also be jetted onto the workpiece, with the steam also physically removing contaminants, and also heating the workpiece to speed up chemical cleaning. The workpiece and the jet of liquid are moved relative to each other, so that substantially all areas of the workpiece surface facing the jet are exposed at least momentarily to the jet.

Abstract: The present invention provides a method of cleaning a chamber of a CVD machine and elements within. A gas mixture of carbon tetrafluoride (CF4) and perfluoro ethane (C2F6) is first injected into the chamber. After performing a surface treatment, comprising a sandblasting step or a polishing step, on the surfaces of the elements, the elements are then immersed in a cleaning solution, comprising at least ammonia water (NH4OH) and hydrogen peroxide (H2O2) at a temperature maintained between 40° C. to 70° C. Finally, the temperature of the cleaning solution is raised so that the residual layer on the surface of the elements can drop from the surfaces of the heater and the process kits or dissolve into the cleaning solution.

Abstract: The present invention discloses a method for cleaning a surface of a substrate where a silicon epitaxial layer will be formed before growing the silicon epitaxial layer in a selective epitaxial growth process. Firstly, a high temperature heating element is aligned in a silicon epitaxial layer growth chamber, disposed separated from the substrate, a cleaning gas is inserted into the chamber and is decomposed into an atom or radical state having high reactivity in a gas phase according to heat generation of the high temperature heating element, and is diffused into the substrate, whereby a substrate cleaning reaction is performed at a substrate temperature ranging from 400 to 600° C.

Abstract: A vacuum debris removal system for an integrated circuit manufacturing device is disclosed. The vacuum debris removal system comprises at least one vacuum tube. An opening is formed in the at least one vacuum tube at a selected location to cause air flow away from an element of the integrated circuit manufacturing device.

Abstract: An apparatus for cleaning castings includes a cleaning cabinet having a rotary clamping device which clamps a casting to be cleaned upon a freely rotatable plate in the cabinet. An elongate lance having a high pressure nozzle at its inner end projects into the cabinet and delivers a high pressure water jet against the casting at a pressure of 1,000 psi to 40,000 psi. A spherical bearing pivotally and rotatably mounts the lance on a vertically reciprocal carriage. A pair of pneumatic cylinder and piston units are connected to lance and are differentially operated with respect to actuation times and length of piston stroke to thereby produce random movement of the lance during the cleaning operation.

Abstract: In this substrate transport apparatus, portions connecting a transport chamber (101) with a first load-lock chamber (109) and a second load-lock chamber (110) are provided to linearly align with each other. A processing station (120, 121) for processing a substrate (400) is provided on a position not interfering with rotational motion and telescopic motion of a robot arm (106). A substrate transport apparatus capable of improving the degree of integration of the apparatus while suppressing enlargement of a foot print and implementing common load-lock chambers can be provided by employing this structure.

Abstract: A substrate dual-side processing apparatus has a processor to apply a specific process to a front surface and a rear surface of a substrate, a reversing unit to reverse the substrate and a substrate-transfer mechanism to transfer the substrate between the processor and the reversing unit. The reversing unit has a holder for holding the substrate when the substrate is being transferred to and from the substrate-transfer mechanism and a rotating mechanism for rotating the substrate, thus the substrate being reversed while held by the holders. The reversing unit may have a pair of holders for holding the substrate at the front and rear surfaces, a drive mechanism for driving the pair of holders so that the holders become close to or apart from each other and a rotating mechanism for rotating the substrate, thus the substrate being reversed while held by the holders.

Abstract: An umbrella with quick connect and rotatable coupling including an umbrella portion having a handle portion. The handle portion has a lower end with an opening formed therein. A main body is coupled with respect to a handle bar. The main body has a generally cylindrical configuration defined by an upper end, a lower end, and an intermediate extent therebetween. The upper end has a connector pin extending outwardly therefrom. The connector pin is receivable within the opening formed in the lower end of the handle portion of the umbrella portion.

Abstract: A switch for folding and opening an umbrella automatically, comprises an engaging tube having a first spring and a second spring, and a buckle; one end of the engaging tube has a tube; a lateral side of the tube having a protrusion; two outer lateral sides of the engaging tube being installed with parallel lateral sides; a button for covering the engaging tube being exactly located upon the receiving space; a central post, a third spring, and a movable block being pivotally installed in the sliding groove, wherein the movable block can slid on the central post freely; a sleeve being a hollow tube for receiving the engaging tube; a post being protruded from another end; an embedding hole being installed on the post at the connection to the wall of the sleeve; an outer edge of the post being installed with an embedding body; and a handle being inserted by the sleeve; and the blind hole being formed with an embedding seat for being embedded by the embedding body.

Abstract: The present invention relates to an improved rib structure of a windproof umbrella, more particularly to the improved rib structure of an umbrella having an airflow guidance function, mainly comprising a main shaft and a predetermined number of external supporting ribs, internal supporting ribs, stretcher ribs, and linking ribs; wherein an auxiliary set of supporting ribs being disposed at the external edge of the pivotal connecting section of the internal supporting, and such set of supporting ribs using an isolating member substantially in “T” shape being coupled to the external supporting ribs such that there exists an appropriate interval between the two ribs, and a ringed latch being disposed at the appropriate location on the periphery of the auxiliary external rib in order to set up a second umbrella layer and form an airflow space in the interval between the two layers.

Abstract: A protective covering device having a weather-resistant sheet of material wound about a spring-loaded roller, which material may be extended off the roller and over an object to be covered in a relatively easy manner, and which material may then be spring-assisted back onto the roller during the uncovering of such object. The spring-loaded roller is positioned with a housing that is either anchored to the same surface on which the object to be covered is positioned, or is mountable to a vertically-oriented surface located near one end of the object to be covered. The opposite end of the cover has a four-point multiple curved contour configuration to provide better wrapping both on the storage roller and about the end of a vehicle to be covered. Elastic attachments between the cover and the draw bar serve to draw it over the vehicle and provide convenient and efficient wrapping of the cover about the end of the vehicle.

Abstract: A tent which includes a body, a door which is connected to the body by a seam line, a zipper sewn and attached to the body and the door, a slider for opening and closing the zipper and connection equipment for holding an open portion of the door. The zipper includes a holder provided with a pair of through holes for holding the slider when a user opens and closes the door. The connection equipment includes an elastic string and a connection portion which is attached to a position which is connected to the seam line and the zipper. With a holder hole of the zipper slider and the connection portion at the bottom of the tent door integrated into the body of the tent, the door of the tent does not reach to the ground while people go in and out, thus making outdoor life more enjoyable and comfortable by preventing the tent door from getting dirty or damaged.

Abstract: A thermoelectric module includes plural thermoelectric semiconductor chips connected in series, first and second substrates, plural first and second electrodes formed on the first and second substrates, first solder through which the first and second electrodes are bonded to end portions of the thermoelectric semiconductor chips. The first substrate includes two or more protrusions protruding toward opposite sides with respect to the second substrate when being viewed vertically. A method of assembling a thermoelectric module in a radiating member includes the steps of mounting the first substrate on a radiating member through the second solder having a liquidus temperature lower than a solidus temperature of the first solder; holding the protrusions by leading edges of support arms where the second solder is melted to push the first substrate toward the radiating member under pressure while rocking the first substrate in a direction orthogonal to the pushing direction.

Abstract: The invention provides a thermoelectric conversion material which is low toxic and can be used at a high temperature of 500° C. or higher without variation in performance, and a thermoelectric conversion device containing the material. The thermoelectric conversion material is formed of an oxide represented by (Ca3-xMx)Co4O9 (M: Sr or Ba, 1.2>x>0.5).

Abstract: An object is to provide an electronic device driven by a solar cell having improved transparency by extremely narrowing photocells.

Abstract: The solar energy converter comprises an electron emitter and an electron collector. They are provided separate from each other in a vacuum vessel. Solar energy in a wide range of sunlight spectrum can be efficiently converted into electric energy by moving electrons from the electron emitter to the electron collector.

Abstract: A solar cell has an active structure including a paint voltage source having a first paint layer structure comprising p-type pigment particles dispersed in a first-layer binder, and a second paint layer structure comprising n-type pigment particles dispersed in a second-layer binder. The second paint layer structure is in electrical contact with the first paint layer structure. The active structure further includes an electrically conductive contact structure having a first electrically conductive contact to the first paint layer structure, and a second electrically conductive contact to the second paint layer structure. At least one of the first electrically conductive contact and the second electrically conductive contact permits light to pass therethrough to the paint voltage source. A capacitive paint layer may be included to store electrical charge produced by the active structure. The active structure may be affixed to a support.

Abstract: In a process for forming on a substrate a transparent conductive film having crystallizability, the process comprises a first step of forming a film at a first film formation rate and a second step of forming a film at a second film formation rate, and the relationship between film formation rates in the respective steps satisfies:

Abstract: A connector (30) in a network of lubrication pipes (31, 32, 33) is provided with a valve (45) that automatically closes off the connector (30) whenever one of the pipes is withdrawn following an incident. Lubricant leaks are thus avoided. The valve plug is cylindrical-conical (46, 47) and it is fitted with a needle (48).

Abstract: The invention relates to a method of draining condensate from a reservoir that communicates with a trap via a drain pipe. The reservoir is subjected to a gas pressure p(reservoir) that can be below atmospheric pressure p(air) or above atmospheric pressure p(air).

Abstract: A float operated fuel tank vent valve has a pair of vent passages with one of the pair larger than the other. A thin flexible elastomeric strip valve has one end attached to the valve body and the distal end bent over the top of the float and attached thereto. The strip valve has a pair of annular sealing surfaces formed thereon each disposed respectively opposite one of the vent passages. Upon refueling of the tank, as the float rises, the strip valve first progressively closes the larger vent passage and then progressively closes the smaller vent passage. As fuel is drawn from the tank by engine operation and the float is lowered, the strip valve is first peeled away from one edge of the smaller vent passage and then completely opens the smaller vent passage. As the float is further lowered, the valve strip is peeled away from one edge of the longer vent passage and then completely open the larger vent passage.

Abstract: There is a valve assembly for controlling the admission of a fluid such as air into a vehicle tyre or other pressure vessel. The assembly includes a housing (1) with a valve assembly (10) movable therein by a predetermined pressure in said vessel against a spring 5A. The valve member (10) is movable from a first position at which ports (14) of an inlet passage (13) in the housing (1) are open to fluid flow into the vessel to a second position at which the ports (14) are closed by the valve member (10). In use of the valve assembly when the valve member (10) is biased to the first position by the spring 5A the fluid can flow into the vessel until pressure therein reaches the predetermined pressure and the valve member (10) is moved to the second position to terminate flow into the vessel. The valve assembly also includes a low pressure indicating means comprising a transparent cap 3A with an opaque band (23) and a collar (8) movable with the valve member (10).

Abstract: An apparatus for flushing a water line includes a pipe, a valve in the pipe, and a controller that automatically opens the valve to allow water to flow through the pipe at preselected intervals and for preselected times. The controller derives power for its operation and the operation of the valve from a solar panel, which stores energy in a battery. The pipe's outflow orifice has a diffuser to slow the flow of water from the apparatus. An erosion mat cushions the impact of the water from the orifice and helps to prevent erosion of the surrounding soil. An alarm notifies passersby that the apparatus is about to flush the lines.

Abstract: A pneumatic valve, includes a housing having first and second ports for entry and exit of an operating gas, a main connection line for linking the ports, and a cross bore intersecting the main connection line. A throttle includes a control element which is received in the cross bore and has a control opening with an effective area which progressively decreases from a first end position to a second end position, as the control element moves in a direction toward the second end position, whereby a counterforce is provided to oppose this movement of the control element. Disposed in the main connection line in series with the throttle is a flow orifice, wherein a gas pressure differential upstream and downstream of the flow orifice, as viewed in movement direction of the control element, is utilized to control the effective area of the control opening.

Abstract: A backflow prevention assembly has a unitary housing with a passage therethrough, two threaded regions formed in an inner surface of the unitary housing, and two valve assemblies positioned in the passage to prevent fluid flow in a direction. Each valve assembly has an annular mount having a threaded outer surface that engages one of the threaded regions on the inner surface of the housing. The threads can be formed by placing a die having a thread on an outer surface thereof in contact with an inner surface of the unitary housing, and pressing on the outer surface of the housing.

Abstract: A damper valve (70) located between a control valve (18) and a power steering motor (22) in a hydraulic power-assisted steering system (10). The damper valve (70) comprises a housing (72) having axially opposite first and second end portions (76 and 78) and an intermediate portion (80) interposed between the first and second end portions (76 and 78). The first end portion (76) is for fluid communication with the control valve (18) and the second end portion (78) is for fluid communication with the power steering motor (22). A flow restricting element (114) is located within the housing (72) and is movable through portions of the housing (72) including the intermediate portion (80) by fluid flow through the housing (72). The damper valve (70) further includes a biasing element (106) for restraining movement of the flow restricting element (114) toward the first end portion (76) of the housing (72).

Abstract: A method of individually adjusting auxiliary hydraulic valves for work vehicles is provided such that they provide different maximum flow rates for opposite flow directions through the valve. The valve is controlled by a flow rate control for setting a maximum flow rate and is also controlled by a proportional control input device having one range of positions for providing a corresponding first range of flow rates in the one direction, a central position for providing substantially no flow, and another range of positions for providing a corresponding second range of flow rates in the other direction.