Abstract: A fluid flow conduit having its interior wear surface containing multiple anti-erosion protrusions for reducing erosion caused by flow of fluids carrying abrasive particles. The anti-erosion protrusions are usually located on radial outer portion of an elbow, and are preferably pyramid-shaped and arranged in a staggered pattern relative to the fluid flow direction, but other similar shapes can be used. The protrusions can be made integral with the conduit interior wall, or attached to the wall by welding individual protrusions, or by welding to the wall curved plates each containing a row of protrusions. Such protrusions reduce erosion in conduits for particulate bearing fluid streams flowing at velocities over about 50 ft/sec, to disrupt the fluid flow pattern, reduce the velocity and change the angle of impingement of abrasive particles, in areas where high wear rates occur and substantially reduce the rate of wear on the conduit surface.

Abstract: A connector 10 for a fluid-flow line comprising a pair of truncated spheres, the inner 14 nesting within the outer 12, with the truncated ends facing in opposite directions. The non-truncated ends of the spheres are each connected to a different circular disc with a grid structure, called an end member 22, 22'. An adjustable tension wire 24 is stretched between the end members 22, 22' and holds the spheres 12, 14 together. A fluid-bearing seal 16 is affixed to the outer surface of the inner sphere 14 and is in contact with the inner surface of the outer sphere 12. A second seal 18 is attached between the spheres 12, 14 but spaced from the fluid-bearing seal 16 to form a seepage space 30 therebetween. The fluid-bearing seal 16 is formed with internal tubes 32 which permit a small leakage flow from the main flow into the seepage space 30 between the upper surface 34 of the seal 16 and the inner surface of the outer sphere 12 so as to reduce friction between these surfaces.

Abstract: A section of tube with a series of inwardly directed projections is placed in the main conduit of a pneumatic applicator, upstream of the primary distribution head. The inner projections in the tube serve to center the direction of the blown granular material into the primary distributor head. The projections are arranged in annular rows with the projections of each row being offset from those of an adjacent row.

Abstract: A duct fitting for connecting a branch duct to a main duct including a tubular body having cutting teeth formed on one end thereof for cutting a hole in the main duct by pressing the cutting teeth against the main duct and rotating the tubular body about its longitudinal axis. Subsequent to cutting of the hole, the cutting teeth are bent into engagement with the interior of the main duct to squeezingly hold the main duct between the bent over teeth and a resiliently deflectable mounting flange provided on the tubular body. An air diversion scoop is mounted in the bore of the tubular body and is pivotably moved so that a portion of the scoop extends from the tubular body into the main duct.

Abstract: A vane pump having a flow regulating bypass valve activated by outlet pressure to direct excess flow back to the inlet is provided with a channeling having an element comprising a plug insertable in the valve housing, which plug has a specially shaped flow bend in the form of an arcate groove that forms a smooth transition for combined flow from a tank fed inlet and from the bypass valve to the pump inlet. This is effected by connecting a channel from the tank inlet and bypass valve to a channel for flow return to the pump inlet which channels are angularly related. Since the valve housing is die cast the difficulty of providing, in a casting, an exactly shaped smooth surfaced and accurately dimensioned transition passage between the aforementioned channels is overcome by the invention.

Abstract: A one-piece turbulator comprising a rectangular frame with two laterally spaced parallel bars having corresponding ends interconnected by end cross bars, and cross-pieces in the frame. The cross-pieces have a portion extending between the parallel bars, and a further portion projecting perpendicular to a plane defined by the axes of the parallel bars.

Abstract: Collapsible turbulator (10) comprises a plurality of substantially rigid sections (12), structure (14) for connecting the sections (12) in end to end relation for relative pivotal movement between an extended position wherein adjacent sections (12) are substantially coplanar, and an operative position wherein adjacent sections (12) are angularly oriented relative to one another, and structure (30) secured to one of the sections (12) for effecting movement of the sections (12) between the extended and operative positions. A method of inserting the turbulator (10) in a bent pipe (36) is also disclosed.

Abstract: A flue control device for slowing the rate at which heated exhaust gases rise through an exhaust stack comprises a cylindrical housing enclosed by end caps, with an offset inlet and outlet being positioned in opposite end caps. The interior of the housing defines a baffle chamber, and a baffle mechanism is positioned in the baffle chamber between the inlet and outlet. The baffle mechanism comprises two overlapping plates, each plate having a prominent flange extending in an upstream direction relative to the flow of gases through the baffle chamber. The flanges interrupt and slow the swirling circular flow of gases as they pass through the baffle chamber. The baffle and housing are of a size such that the cross-sectional area of the restricted portion of the housing adjacent the baffle is at least as large as the cross-sectional area of the exhaust stack.

Abstract: A device for converting a stream of a slurry or liquid flowing down a tube into a flat stream having a uniform flow across its width and, if a slurry, a uniform particle size distribution across that width. The device comprises a vertical tube from which the slurry or liquid may flow onto a horizontal first plate in an even laminar flow and a second plate adapted to receive medium flowing over the edge of the first plate disposed below the first plate and inclined relative thereto. Metering of the amount of medium flowing onto any one increment of the width of the second plate so that it will be substantially equal to the amount of medium flowing down any other increment of equal width is achieved by the use of a first plate having a closely defined peripheral shape or by the use of vertical dividing members spaced around the periphery at uniform angular spacings which direct the medium onto equal width increments of the second plate.

Abstract: A cooling plate for insertion into the lining of a blast furnace or the like wherein the plate is adapted to have a chamber with cooling water channels for the passage of cooling water therethrough and having a unique baffle means for dividing the flow of water to increase the velocity of flow and avoid stagnant zones.

Abstract: Systems for mixing gaseous medium streams at different temperatures are for changing the direction of flow of a stream which alleviate the effect of pressure losses. A plurality of hollow airfoil shaped vanes are positioned within a first gaseous stream, and the second stream is conveyed through the hollow vane and discharged into the first stream through a slot at the trailing edge of the vane. Fixed or movable flow direct the rate and direction of the discharge flow.

Abstract: A rail for mounting sheet metal turning vanes includes a sheet and integral vane guides extending generally perpendicular away from the plane of the sheet. Each vane guide is a plate slit from the sheet except for one edge along which the plate is bent. The plate is adapted for positioning adjacent to a wall of the vane. An access aperture, partially located in the sheet and partially located in the plate, is adapted to allow access to a portion of the vane wall for contact by a striking tool. A blow from the tool splits the sheet metal vane wall to form tabs which are folded through the aperture, which securely attach the wall to the rail.

Abstract: A mixing element for a motionless mixer comprises a passage tube through which fluids flow and a helical blade formed in the passage tube so as to be integral therewith. The interior of the passage tube is partitioned by the blade to form a plurality of fluid passages. The blade extends from one end of the passage tube to the other in the longitudinal direction of the passage tube to be twisted helically clockwise (right-handed) or counterclockwise (left-handed). The corner portions of the fluid passages are rounded. The end edges of the blade are curved in the direction of the thickness and rounded. The motionless mixer is formed by alternately and longitudinally coupling right- and left-handed rotation type mixing elements. The mixing elements are so arranged that the facing end edges of the blades of each two adjacent mixing elements cross at right angles.

Abstract: A method is provided for flow straightening and sampling gas in the stack of a gas scrubber. In normal operation the gas has a substantially nonaxial flow so as to retain within the stack droplets carried by the gas. A flow straightener having flow straightening panels is assembled in the chamber of the gas scrubber and lifted into the stack. Gas having an axial flow is then sampled. The flow straightener is then removed from the scrubber, and normal operation is resumed.

Abstract: To achieve uniform gas flow in a chamber to which gas is fed from a cylindrical pipe, the pipe has a closed end wall, at least two spaced rectangular apertures on one side near said end wall and, between each adjacent pair of apertures, a radial partition wall, having a central circular aperture. The arrangement is applicable to gas flow to a gas burner or a gas filter.

Abstract: An elbow is disclosed for use in effecting short radius turns in fluent transport systems while overcoming the previous problem of high wear at the turn. The subject elbow includes entry and exit ports at right angles to each other, an arcuate channel extending between the ports, and a chamber aligned with but axially offset from the entryport. The effect of this chamber is to provide abrasive resistance for the elbow by allowing a soft plug of the fluent material to form therein. The material forming the plug will rotate in a vortex manner in the chamber. The subsequently passing fluent material will deflect off of the soft plug rather than rub on the walls of the elbow while making the direction change. The elbow may be provided with an optional purge vent entering into the chamber.

Abstract: Disclosed is an angled gas conduit for a gas flowing under high pressure and at an elevated temperature which comprises a first conduit part and second conduit part connected at an angle forming an area of deflection for gas flowing within said conduit parts, an apertured plate arranged at an oblique angle within said conduit in the area of deflection, the apertured plate having a plurality of circular passages for directing the flow of gas in the conduit. A mounting arrangement for the apertured plate is also disclosed.

Abstract: A filter apparatus having an inlet duct (30) with a plurality of vanes (10) therein. Each vane (10) is positioned in the fluid duct (30) and adapted for deflecting fluid as it moves through the duct (30) and further for preventing the accumulation on the vane (10) of particulate matter entrained in the fluid. Vane (10) comprises a vane body (11) defining a forward edge portion (12) which faces upstream into the moving fluid. Forward edge portion (12) has a pre-determined angle of incidence to the direction of travel of the moving fluid sufficient to overcome frictional adherence of the particulate matter. Vane body (11) also has a free end (16) spaced apart from the inner walls of duct (30). The vane body (11) also defines a rearward edge portion (13) downstream of forward edge portion (12) and defines an angle within duct (30) corresponding to the extent of deflection to be applied to the moving fluid. One of the embodiments includes alternating vane bodies (11) positioned on opposite walls of the duct (30).

Abstract: The reaction gas throughout of the supply duct feeding gas to the bottom of a fluidized bed reactor of the kind shown in U.S. Pat. No. 4,153,004, issued May 8, 1979, is increased by providing the reaction gas supply tube in the form of a bundle of tubes of small cross-section of about 2 mm diameter. Subdivision of the supply tube into hexagonal ducts in honeycomb arrangement maximizes the useful cross-sectional area of the supply tube. With the smaller elemental tube diameters, a higher rate of flow is maintainable without loss of laminar flow behavior, which behavior is maintained in the jet issuing from the subdivided reaction gas supply duct as it flows towards the constricted entrance into the fluidized bed container while being surrounded by a sheath of inert carrier gas supplied by an annular duct surrounding the reaction gas tube.

Abstract: A solar collector of the tubular type comprising a solar energy transmissive outer tube encircling a solar energy converter inner tube disposed for having a flow of fluid directed longitudinally through it. The outer and inner tubes have respective opposing end portions sealed to one another and respective mid-portions radially spaced from one another for forming an interposed vacuum chamber. The sealed joints may include at least one flexible member disposed to compensate for differences in thermal characteristics of the inner and outer tubes. The inner tube is provided with an exhaust tubulation which communicates with the vacuum chamber for evacuating the chamber, and extends inwardly of the inner tube for producing turbulence in the flow of fluid to aid in the transfer of heat energy from the inner tube to the fluid.

Abstract: An ejector comprising a housing (30, 81) and an ejector insert (40, 82) received therein to form a venturi which is eccentric with the housing, and a muffler-ejector assembly (25), including such an ejector (80), so mounted that the inlet axis (78) of the exhaust tube (71) may be made to approach or even coincide with the axis (59) of the casing (60) without enlarging the lateral dimensions of the latter.

Abstract: A bag-type filter apparatus, whose gas-permeable tubular filter bags are cleaned by a periodic reverse purge flow of air directed into one end of the filter bag, has a combination filter bag support and air diffuser for each filter bag and which is characterized in that the support holds the filter bag in an open tubular configuration throughout the length of the filter bag, but the air diffuser is of shorter length than the filter bag to more effectively clean the filter bag.

Abstract: The fluid throughput of a conduit is increased without increasing the power requirements or the size of the conduit by affixing to the inner surface of the conduit at least one airfoil located with its leading edge facing into the flow substantially at the beginning of rectilinear flow. The airfoil advantageously has a body portion, a head portion, and a tail portion wherein the body portion has upper and lower planar surfaces defined by substantially parallel planes, side portions defined by substantially parallel side planes which are substantially normal to the upper and lower parallel planes, the head portion has a bulbous portion extending substantially below the lower parallel plane and the tail portion extends substantially below the lower parallel planes but not as far below as the bulbous portion.

Abstract: Individually adjustable D-port inserts for securement to an engine header and projecting therefrom into exhaust ports to occupy the stagnation areas thereof and in each instance placeable for fine tuning thereof to optimize flow, and removeable with the header without alteration of the exhaust port configuration established thereby.

Abstract: The present invention relates to an apparatus for dampening pulses in a hydraulic system and is characterized by the provision of a hydraulic accumulator device having disposed in the hydraulic flow path a baffle member shiftable from the exterior of the dampener in a direction normal to the flow path and toward and away from the oil port of the accumulator whereby the device may be critically adjusted or tuned to deal effectively with pulses of a variety of frequencies and amplitudes.

Abstract: A spherical-shaped, honeycombed segment for positioning downstream of a bend or turn, in an air flow duct for rapidly returning air flow to a uniform, or predictable, cross-sectional flow.

Abstract: In storage apparatus wherein asphalt hot mix is moved by gravity along a chute from the top of a bucket elevator to the inlet of a batching hopper at the top of a storage bin, a baffle in the chute, over the inlet, prevents segregation of mix entering the hopper. The baffle is spaced forwardly of the front end of the chute bottom wall, is oriented generally vertically and transversely to the length of the chute, and is flatwise swingable backward and forward. By means of a set screw through a front wall of the chute the position of swinging motion of the baffle is so adjusted that coarse mix components, carried against the baffle by momentum, are deflected by it towards the center of the hopper. Adjustable remixing baffles in the chute, adjacent its side walls and behind the front end of its bottom wall, deflect material away from the chute side walls to effect remixing of aggregate that became segregated during its charging into the bucket elevator.

Abstract: A crossover duct assembly for providing flow communication between multiple stages of centrifugal compressors and the like. The duct assembly includes inner and outer wall sections forming a continuous annular flow path between compressor stages for turning radially outward gas flow to a radially inward direction. The duct includes a thin vane diffuser section, a vaneless turning bend having an elongated wall geometry, and a deswirl vane section for enhancing smooth gas flow with minimum pressure loss.

Abstract: A pulse dampener device in which the effective cross section of the flow path through the dampener assembly may readily be varied thereby enabling the device to be adjusted or tuned to deal most effectively with any of a variety of pulse variables encountered in a particular installation.

Abstract: A system for suppressing cavitation in fluid pipeline passages such as fluid loading arms, particularly of the marine type, comprising extended turning vanes in the elbows of the loading arm, preferably in the upstream direction from the elbow tangent point, and also including the capability for adjusting the attack angle of the vane relative to the pipe axis. The combined effect of the extended vane and the negative attack angle improves cavitation performance to a greater extent than each of these expedients when used separately. This system obtains increased flow rates without significantly increasing the system back pressure and the adjustability of the attack angle will allow for optimization relative to changes in products and flow conditions.

Abstract: A flow device and method delivers a gaseous medium to utilization equipment having variable pressure conditions at its intake. A gaseous medium intake zone connects with structure defining a variable area throat zone for constricting the flow of the gaseous medium to increase its velocity to sonic. Wall structure downstream from the throat zone provides a gradually diverging zone for efficiently recovering the kinetic energy of the high velocity gaseous medium as static pressure. Perforations are provided in the wall structure downstream and spaced from the throat zone, and these perforations connect on the back side of the wall structure with the intake of the utilization equipment. When supersonic flow occurs the high velocity mass moving past the perforations pulls a small portion of the gaseous medium already delivered to the intake of the utilization equipment into the gradually diverging zone.

Abstract: A process for achieving a uniform flow profile of very viscous liquids when flowing through tubes or reaction chambers, wherein the very viscous liquid is passed through annular spaces extending concentrically with increasing diameter over the entire cross-section of the tubes or reaction chambers and having the same depth in the direction of flow, and this procedure is repeated once or several times, the annular spaces being staggered with respect to each other as viewed in the direction of flow, and an apparatus consisting of a combination of two or more discs arranged at axial intervals within a tube transversely to the direction of flow, each disc consisting of a plurality of ring-shaped bands of increasing diameter, the bands being arranged freely of one another and concentrically at intervals on a grid supporting means to provide correspondingly concentric open spaces between the bands over the entire cross-section of the tube, with the walls of the bands running parallel to the direction of flow, and t

Abstract: A flow device and method delivers a gaseous medium to utilization equipment having variable pressure conditions at its intake. A gaseous medium intake zone connects with structure defining a variable area throat zone for constricting the flow of the gaseous medium to increase the velocity thereof to sonic. The throat zone is adjustably varied in correlation with operating demands imposed upon the utilization equipment. Wall structure downstream from the throat zone provides a gradually diverging zone for efficiently recovering the kinetic energy of the high velocity gaseous medium as static pressure. Through such efficient recovery the velocity of gaseous medium through the throat zone is sonic over a wide range of pressure conditions at the intake of the utilization equipment. A flow splitter is spaced from the adjustable throat zone and the splitter is arranged to divide the downstream end portion of gradually diverging zone into multiple zones of reduced divergence.

Abstract: A flow preconditioner for an electrostatic precipitator which removes particulate matter from a stream of polluted gas immediately after it passes through a tangential inlet at the lower end of a vertical cylindrical housing and straightens and divides the stream into laminations parallel to the axis of the housing. It comprises an annular ledge or choke ring extending inwardly from said housing above the inlet and an assembly of vanes above said ledge extending radially from the axis of the housing and angularly spaced apart. Each of said vanes has a flow receiving edge directed toward said inlet, a curved portion extending upwardly and away from said inlet, and a flat portion extending upwardly from said curved portion in a plane parallel to the housing axis.

Abstract: To minimize loss of pressure energy in metering fluid flow by means of primary flow tube elements, the contour of the throat inlet section of the flow tube is that which produces a constant rate of acceleration of flow through the inlet to the throat section. The contour equation is given. At least in larger sizes of flow tubes, the inlet section is formed of thin metal such as stainless steel and arranged in such a way that it is not subject to mechanical stress in the installed assembly.

Abstract: A heating wall for coke ovens with horizontal coking chambers comprises vertical heating flues arranged in pairs, every pair of adjoining heating flues being separated by a partition formed with a flow port in the upper portion. Lateral sides of the flow port are provided with vertical slot-like guides which accommodate projections of a slide gate. The guides are formed in their upper portion with stepped recesses the vertical extent of which exceeds the length of the slide gate projections. The slide gate center of gravity is shifted with respect to the longitudinal axis of its projections in the direction opposite to the stepped recesses. The slide gate is provided with means for introducing a hook and vertically moving the slide gate into its uppermost and lowermost position in the flow port. As a result, the flow port vertical position is changed substantially without changing the clear opening of the flow port.

Abstract: The invention relates to a process for the manufacture of a generally flat triangularly shaped metal deflector for installation to the interior non-tangential surface of an inlet pipe to the bowl of a centrifugal separating cyclone. The deflector constricts the inlet cross section to the bowl by about 19% to about 32%. The process comprises the steps of selecting a pipe section of the same size as the inlet pipe and marking the chord ends at the center angle between 118.degree. and 149.degree., preferably close to 120.degree.

Abstract: A noise suppressor for fluid systems may comprise: a cylindrical housing, having an inlet and an outlet, through which fluid may flow and a baffle assembly disposed in the housing providing a path for the flow of fluid whereby the flow is diverted from one side of the housing to the other as fluid flows between the inlet and outlet. A perforated plate member may also be transversely disposed in the housing between the baffle assembly and either the inlet or outlet.

Abstract: The head box guide is formed of a metal block with cylindrical bores into which a pair of telescoping plastic inserts are fitted. Each pair of inserts are formed so as to define a stepped widening within the block. In addition, the inserts have terminal parts which are disposed outside of the bores and which are locked together in contiguous fashion so as to avoid any gaps. Also, a honeycomb connecting member rests on the downstream terminal parts of the inserts to form continuations of the flow passages.

Abstract: Device for stabilizing flow through radial bores formed in a hollow rotation cylinder wherein a gaseous medium passes from a stationary chamber surrounding the hollow rotating cylinder through nozzle-like openings formed in a wall of the hollow rotating cylinder into the interior of the latter, includes a stationary ring disposed in the stationary chamber surrounding the hollow rotating cylinder, the stationary ring partly covering the openings formed in the wall of the hollow rotating cylinder.

Abstract: A pipe cross fitting for interconnecting tubular structural members of an offshore platform of the type used by the oil industry. The cross fitting is reinforced by the addition of an internal structural element that extends across the central open portion of the fitting and into all of the branches of the fitting to resist the tension and compression forces applied to the fitting during use.

Abstract: An air barrier device using pressurized swirls for creating an air curtain barrier across a building opening, such as a door or window, to reduce heat transfer and thereby reduce both winter and summer energy losses. The device comprises a housing with an air intake for mounting within the building above the opening to be protected, a number of air discharge ducts having internal means for whirling the air passing therethrough and arranged to discharge the air downwardly across the opening as a series of distinct adjacent, oppositely rotating, pressurized swirls to form an air curtain barrier to energy transfer in either direction through the opening, and a blower mounted in the housing to receive air from the intake and discharge it through the ducts.

Abstract: A seal for flow passages has directional characteristics allowing gases or fluids to flow freely in one direction while restricting the flow in the opposite direction. The seal includes a flow diverter cone (or other inclined surface) which is spacedly mounted on a flow inverter cone (or other inclined surface) in a passage to effectively reverse the direction of undesired counterflow of gases without restricting normal gas flow. The seal has no moving parts but serves as an effective aerodynamic valve. Addition of this seal to the stack of a flare system, or to other chimneys, restricts the flow of air into the stack while allowing the waste gases to be exhausted with negligible restriction.

Abstract: Fluid flow diffuser has a first divergent duct connected by a sudden enlargement of flow area to a second divergent duct. The enlargement is defined by a fence situated downstream of the downstream end of the first duct. The top of the fence is on a flow perimeter intermediate between the downstream end of the first duct and the upstream end of the second duct, the latter end being defined by the bottom of the fence. An opening defined by the downstream end of the first duct and by the top of the fence gives access to a chamber connected to a pressure less than that at latter downstream end thereby to generate a vortex having a surface bridging the opening and assisting transition of flow from the first duct to the top of the fence. A second vortex formed immediately downstream of the fence assists transition of flow from the top of the fence to the surface of the second duct. The first duct has a rate of divergence low enough to avoid boundary separation.

Abstract: The flow straightener is used in piping for papermaking machines and employs ribs which are angled at the front edge to a plane perpendicular to the flow path to avoid fiber accumulations thereon. The ribs can be disposed in tube bends or elbows and can be used in circular or rectangular pipes.

Abstract: Cylindrical body the outer periphery of which is provided with means to counteract vibrations occurring in that body as a result from transverse flow against it, these means comprising a number of small planes mounted according to a certain pattern and placed substantially perpendicular to the outer periphery of the body, which planes form an angle of from 5.degree. to 25.degree. with the cross-section of this cylindrical body; the surfaces of these planes at the most amounting to 2.5% of the surface of the cross-section of the cylindrical body and their lengths at most to 20% of the diameter of this body.

Abstract: A supersonic diffuser having a plurality of blades therein for dividing the diffuser channel into a plurality of approximately axisymmetric ducts wherein a portion of said ducts ingest a boundary layer along at least one of the walls of the supersonic diffuser. The blades in the diffuser channel have their upstream ends bent away from the wall having the boundary layer to redirect the flow into the ducts. In one embodiment the wall between the duct having the boundary layer and the duct adjacent to the duct having the boundary layer is made in two sections with both sections being bent away from the wall having the boundary layer, to provide internal redistribution between the two ducts.

Abstract: A fluid circulating apparatus includes a housing which forms a part of an aggregate, for instance a heat exchanger. The housing has an inlet portion for admission of fluid into a first compartment and an outlet port which communicates with a pressure chamber of the housing. One wall of the housing has at least one aperture through which fluid can flow from the first compartment into the heat exchanger proper, and at least one second aperture through which fluid flows from the heat exchanger proper into a second compartment. A pump in the pressure chamber draws fluid from the second compartment through an opening in a funnel-shaped member extending transversely through the housing and discharges pressurized fluid into the pressure chamber. An inclined wall extending between the funnel-shaped member and an opposite housing wall separates the first from the second compartment.

Abstract: An improvement to the controllability of aircraft wherein vortex generators are connected to a control surface in front of the hinge line of the control surface so that when the control surface is deflected, the vortex generators project into the airstream on the opposite side from the deflecting control surface. The action of the vortex generators causes the airflow to remain attached to the control surface at higher angles of attack than would otherwise be possible thus increasing the lift of the airfoil and control surface.

Abstract: A jet flow alternator for reversing the flow of a confined fluid stream which includes selectively controlled tubes to cause said stream to flow in either one of two directions under pressure.