Abstract: An agricultural sprayer includes a spray boom equipped with a plurality of spray heads, with each head having a body defining a cavity located in fluid communication with a fluid inlet and an array of four outlets leading to four nozzles respectively having different flow rates. A nozzle-select control member is mounted for rotation in the cavity and includes a fluid passage arrangement for establishing fluid connections between the inlet and different ones or combinations of the four nozzles as the control member is rotated among preselected discrete positions by an electric stepper motor, with the stepper motor being controlled in response to vehicle speed so that the spray tip capacity decreases for effecting a constant application rate as the vehicle speed decreases from a maximum permitted speed.

Abstract: A method and apparatus for depositing a fluid over an interface. A nozzle may comprise a body having a first end and a second end, an input located at the first end of the body, an output located at the second end of the body, and a plurality of channels located within the body. The input may be configured to receive a fluid. The plurality of channels may have a configuration that causes the fluid received through the input to flow through the plurality of channels and exit the output to form a deposition having a desired shape over an interface.

Abstract: A water separation structure of a shower head includes a cover unit, a cover seal seat and a main body seal seat. The cover unit has three water outlets. Three water passages and a shift water passage are formed between the cover seal seat and the cover unit. The cover seal seat has five through holes. The main body seal seat has a water inlet and a blind hole which are spaced and located corresponding to the five through holes. The water inlet comprises a seal ring therein. The blind hole comprises a seal pad therein. The water inlet communicates with one of the five through holes by means of rotation to open the relative water passage. The blind hole is to block the other through holes and close the other water passages. The seal ring and the seal pad are against the cover seal seat.

Abstract: The present invention is directed to an apparatus for producing a water maze from walls of falling water that can be reconfigured to change the maze. In one embodiment, the apparatus is comprised of a plurality of spray bars that are each capable of producing a separate wall of falling water droplets and a plurality of water valves that are each associated with only one spray bar. The water valves can be used to define at least two different paths between the entrance and exit of the maze. The apparatus is also capable of being used to create interesting visual effects by projecting light/images on to multiple screens created by walls of falling water droplets.

Abstract: This invention disclosed a mixed-mode fuel injector with a micro-variable-circular-orifice (MVCO), which is a fuel injection device for internal combustion engines, either diesel or gasoline engines. The fuel injector has means of generating variable mixed-mode sprays of conical and multi-jet shapes.

Abstract: A water separation structure of a shower head includes a cover unit, a cover seal seat and a main body seal seat. The cover unit has three water outlets. Three water passages and a shift water passage are formed between the cover seal seat and the cover unit. The cover seal seat has five through holes. The main body seal seat has a water inlet and a blind hole which are spaced and located corresponding to the five through holes. The water inlet comprises a seal ring therein. The blind hole comprises a seal pad therein. The water inlet communicates with one of the five through holes by means of rotation to open the relative water passage. The blind hole is to block the other through holes and close the other water passages. The seal ring and the seal pad are against the cover seal seat.

Abstract: A shower having a shower area changed with variation of water pressure includes: a holding unit, in which a water channel is designed and a feed-water valve is added on the top of the water channel; a spraying water unit, which is sealed with the holding unit, comprising at least two spraying water groups that are a main spraying water group and at least one branch spraying water group; and at least one movable unit, whose number is equal with the number of branch spraying water groups, assembled with the branch spraying water groups in one to one correspondence. In order to change the shower area, we could regulate the opening and closing of the feed-water valve to control water pressure.

Abstract: Apparatus for applying fluids such as adhesive, in particular hot melt adhesive, to a substrate. The apparatus includes a main body which can be connected to a fluid source, an application valve for selectively interrupting or enabling a flow of fluid, and a nozzle arrangement arranged on the main body for applying the fluid. The nozzle includes a distributor passage communicating with the fluid source, and the nozzle arrangement has at least one outlet opening for delivery of the fluid, which communicates with the distributor passage, and a closure body arranged movably in the distributor passage for varying the length, which can be acted upon with fluid, of the distributor passage. The distributor passage is provided in a one-piece portion of the nozzle arrangement.

Abstract: An injection nozzle for an internal combustion engine comprising a nozzle body defining a seating surface and having at least one first nozzle outlet and a valve member received within the nozzle body and engageable with an external seating defined by the seating surface so as to control fuel injection through the at least one first nozzle outlet. The valve member is provided with a bore having an internal bore surface and an insert is received within the bore. The insert includes a part-spherical head which spans an internal diameter of the bore so as to maintain contact with an internal surface of the bore as the valve member moves, in use, so as to guide movement of the valve member. The part-spherical head also includes a surface which defines an internal seating for the valve member.

Abstract: A showerhead has at least a first set of nozzles and a second set of nozzles for discharging water. The showerhead discharges water according to one of multiple water delivery functions, where a first water delivery function corresponds to water being discharged through only the first set of nozzles, a second water delivery function corresponds to water being discharged through only the second set of nozzles and a third water delivery function corresponds to water being discharged through the first and second sets of nozzles simultaneously. The spacing between the first set of nozzles and the second set of nozzles is carefully selected so that the third water delivery function corresponds to the integrated nozzles of the first and second sets of nozzles. As a result, the third water delivery function provides a coherent and balanced water flow resulting in a more pleasant feel.

Abstract: An injection nozzle for use in delivering fuel to an internal combustion engine includes an outer valve (24) which is engageable with an outer valve seat (38) so as to control fuel delivery into the engine through a first nozzle outlet (26) and an inner valve (32) which is slidable within a bore (30; 130) provided in the outer valve (24) and engageable with an inner valve seat (40) so as to control fuel delivery into the engine through a second nozzle outlet (28).

Abstract: A device for dispensing fluid onto a substrate that is movable relative to the device. The device includes a basic body that has a fluid supply channel which is connectable to a fluid source. A slotted nozzle assembly communicates with the fluid supply channel. The slotted nozzle assembly is formed on or attached to the basic body and has a slot-shaped discharge opening for dispensing the fluid. A fluid valve selectively interrupts or releases the fluid stream. The basic body and/or the slotted nozzle assembly have a plurality of segments which are situated adjacent to each other in the direction of the longitudinal extension of the slot-shaped discharge opening.

Abstract: A multi-function showerhead has at least a first set of nozzles forming first curves and a second set of nozzles forming second curves. The showerhead discharges water through the first curves when a first water delivery function is selected and through the second curves when a second water delivery function is selected. The first curves and the second curves are interleaved so that a coherent and balanced spray pattern is provided resulting in a pleasant showering experience, regardless of the selected water delivery function.

Abstract: A switch-equipped sprinkler including a main body, a rotary water-distributing switch and a color-changeable warning facial cap mounted in a facial cap of the sprinkler. The switch is mounted in the main body. The switch has an operating handle arranged between the facial cap and the handle of the sprinkler. In the case that the temperature of the water exceeds a set value, the color-changeable facial cap will warn a user. The switch is operable with single handle to control the path of the water flow and switch the figures of the sprinkled water as necessary.

Abstract: The applicator device (AV) for hot-melt adhesive (HK) comprises a housing (1) with an adhesive feeder element (2) and an adjustable nozzle slot (3) to let out the adhesive by pressure. The nozzle slot (3) can be adjusted by means of two nozzle sliders (4) that can be displaced linearly and continuously towards each other from a zero position to a maximum open position with the purpose of adjusting the width (B) of the adhesive applicator. Both sliders (4) are displaced synchronously or independently towards each other, whereby both sliders (4) can be displaced towards each other by the same distance and/or by a different distance from the center (0) of the application width (B) of the nozzle slot (3).

Abstract: A throttleable rocket injector assembly is disclosed wherein the flow of oxidizer into each of the oxidizer injectors is simultaneously regulated by a mechanical assembly mounted entirely within the oxidizer chamber.

Abstract: A mobile asphalt dispenser for applying strips of asphalt having prescribed widths to a roof. The dispenser has a frame including an asphalt container for holding the asphalt. At least one wheel is rotatably mounted on the frame. A valve assembly is provided in fluid communication with the asphalt container and is operable to control flow of the asphalt from the container to the roof. The dispenser has a valve assembly selectively positionable into at least three prescribed positions, each of the prescribed positions corresponding to a respective one of the prescribed widths of the asphalt strips. In addition to or as an alternative to the valve assembly, the dispenser may include a side dispensing arm for applying asphalt to a cant of the roof. Preferably, the dispenser is provided with a swivellable wheel.

Abstract: The present disclosure concerns a fluid dispersion system such as for use in a personal shower. Groups of nozzles on a single showerhead are separately activated and regulated by corresponding valves. Each valve is controlled from a remote panel to provide an appropriate flow of water. A position detection system determines the relative position of a body with respect to the showerhead. The remote panel receives data from the position detection system and adjusts the valves to ensure the user remains in a desired flow of water.

Abstract: An irrigation device has an arm which is rotatably fastened at its ends to a pair of side elements of the irrigation device, and from one of which elements there extends a driving shaft. The device comprises a cam substantially in the shape of a heart integral with the shaft, a connecting rod coupled to the cam by the of a pair of shoes that engage the perimeter of the cam in substantially diametrically opposite positions. The connecting rod is provided with a slot wherein a guide for the connecting rod is engaged integral with the cam, and a crank integral with arm. The connecting rod can be hinged to the crank in a plurality of positions substantially aligned along a radial direction lying in a plane orthogonal to the axis of rotation of the arm and placed at different distances from the axis of rotation.

Abstract: An applicator head for the metered release of flowing media, particularly hot-melt glues, cold glue paste, lubricants, paints, or similar substances, comprises a housing within which there is disposed a pivoting rocker having two oppositely disposed rocker arms which are operatively associated with two valve mechanisms. Two stacks of piezoelectric elements are disposed upon opposite sides of a rocker axis such that when a particular one of the stacks of piezoelectric elements is energized or activated, the rocker is pivoted about the rocker axis whereby one of the valves is opened while the other valve is simultaneously closed. In accordance with one embodiment of the invention, one of the valves is an applicator or dispensing valve and the other one of the valves is a closing or recirculation valve operatively connected to a recirculation system. In accordance with a second embodiment of the invention, both valves are applicator or dispensing valves.

Abstract: The invention is directed to a spray cooler for regulating the temperature of superheated steam with a stream of cooling water. Its primary inventive feature is directed to a throttle area which has a continuously widening cross section disposed on a piston rod and arranged between the cooling water inlet opening and the nozzles of the spray cooler. The throttle area serves to regulate the pressure the cooling water in proportion to the movement of the piston carrying the throttle.

Abstract: The present invention relates to a fire fighting equipment, comprising at least one spray head (1) with a number of nozzles (3) directed obliquely sideways. The nozzles (3) are arranged so close to each other that the fog formation areas of the individual nozzles intensify the fog flows and provide a suction to cause the fog formation areas to be compressed into a continuous directional fog spray.

Abstract: An apparatus and method for dispensing water in a radially uniform distribution over a surface. The reciprocating sprinkler device includes a housing, an inlet port for receiving water under pressure to the housing, at least two outlet ports capable of dispersing water in differing directions, and a reciprocating water driven valve. Each outlet port includes an opening for receiving water from within the housing. The reciprocating valve alternately covers portions of the outlet port openings as it moves, thereby modulating the flow of water between the outlet ports resulting in increasing and decreasing flows of water across a surface.

Abstract: An irrigator comprises an oscillating arm (1) formed by a hollow cylinder provided with a longitudinal succession of holes (8) suitable for passage of an irrigation liquid. An operation unit (6) oscillates the arm about its own axis. A cylindrical sleeve (9) is inserted coaxially and rotatably in the oscillating arm, and has thereon at least one surface groove (11) for channeling the irrigation liquid whereby the irrigation liquid is emitted through the holes in the arm aligned with the surface groove. The sleeve has a terminal section (13) and a remaining section (12), and the groove (11) has a terminal groove section in the terminal section of the sleeve and a remaining groove section in the remaining section of the sleeve. The terminal section (13) of the sleeve is rotatable with respect to the remaining section (12) of the sleeve, to allow the terminal groove section to be staggered with respect to the remaining groove section for controlling the flow of irrigation liquid from the oscillating arm.

Abstract: A light-weight turf conditioning machine provides programmable subterranean soil processing. The machine includes a set of electronically controlled air guns that are mounted on a frame a given distance above the ground. Each air gun disperses a high pressure stream of fluid into the ground in a vertically aligned cylindrical shape drilling holes into a golf green. The holes are drilled using a hydrated polymer that absorbs and releases moisture in a controlled fashion fostering plant growth. A programmable controls circuit controls the rate, pattern and depth in which holes are drilled into a golf green. A portable storage tank is fluidly joined by a hose to the air guns. The hose allows the storage tank to spaced from the machine as the air guns are carried over the golf green.

Abstract: An oscillating sprinkler adjustable to selectively alter and adjust the spray pattern as desired is provided. Adjustment is provided by an internal selectable cam connected to an external rotary dial at the distal end of the sprinkler. Placing the spray adjustment dial at the distal (non-hose) end of the sprinkler minimizes the chances of the operator getting wet while selecting the desired spray pattern while the sprinkler is in operation.

Abstract: A nozzle bar apparatus for applying a pattern of a viscous material upon a portion of a substrate where the apparatus is adjustable to vary the length, width and position of the pattern relative to the substrate including a nozzle member for selectively dispensing the material in a predetermined pattern and frequency including at least one material flow path through the nozzle member, the flow path having a first end forming an outlet facing the substrate for dispensing the material to the substrate and a second end in operable communication with a material supply for providing a flow of viscous material, the outlet having a predetermined range defining a width of the pattern, the nozzle member being activated for a selected period of time to control a length of the pattern and including a pattern control mechanism for selectively varying the width as well as the position of the pattern anywhere across the range of the outlet.

Abstract: The invention relates to a linear burner with jets extending through an opening made in a wall of a body of the burner defining an air-distribution chamber. According to the invention, the jets are connected to a series of tubes for supplying fuel gas or a gas/air mixture, these tubes passing through the body of the burner in order to be connected on the outside to a distribution housing provided with gas or with a gas/air mixture, this housing comprising adjustment means for selectively supplying the tubes joined to the jets.

Abstract: A system is provided for introducing fluids into a wind stream. Such fluids may be used to cool the orchard during the late summer and early fall, to aid in prevention of frost damage during the spring, or to distribute agricultural chemicals. This invention ensures that the fluid is introduced into the wind stream in the most efficient manner, thus ensuring economical use of fluids and minimizing any detrimental environmental effects of their use. The fluid introduced into the wind stream is of such a fine character that the fluid is broken up into a mist which will carry over a great distance, such as a fog.

Abstract: A nozzle (10) with lateral slots (16, 17 and 18) for discharging a high pressure liquid for treating a work material (30) is described. The nozzle has a constriction orifice (15) between an enlarged or main orifice (13) and restriction orifice (14) leading to the slots which increases the velocity of the liquid issuing from the slots. The nozzle is particularly adapted for deburring transmission fluid channels in transmission main control valve bodies.

Abstract: A method of detecting spray header valve and nozzle malfunctions, in a spray header including plural nozzles each having its own control valve, by supplying the spray header with liquid at a constant pressure head through a conduit while opening and closing the nozzle valves one at a time, and measuring the flow rate through the conduit each time one of the valves is open and when all the valves are closed. In response to detection of a malfunction at a particular nozzle, the valves of one or more adjacent nozzles are adjusted so that the adjacent-nozzle flow rates compensate for the malfunction, for example to maintain a desired cooling pattern across a surface being cooled by the spray header notwithstanding the malfunction at the particular nozzle.

Abstract: An improved dispenser for granular materials is disclosed, comprising upper and lower fixed plates and a rotating intermediate plate. The upper and lower plates have orifices formed in them which are out of register with one another. The relative extent of these orifices is chosen in accordance with the material to be dispensed such that the material only flows through the plates when the intermediate plate is rotating.

Abstract: A valved flow control dispenser including a slot nozzle through which molten thermoplastic material is dispensed onto a substrate. The slot nozzle includes a nozzle body within which there is a transverse cylindrical bore, which bore is intersected by two spaced radial openings. One of these openings is in fluid communication with a pressurized source of molten thermoplastic material, and the other opening is in fluid communication with a slotted discharge opening of the nozzle. A cylindrical flow control member having a groove provided in its exterior surface is rotatably mounted within the bore. This groove is of varying width and provides a flow path for molten thermoplastic material between the openings in the bore. By varying the rotatable orientation of the cylinder relative to the openings, the width of molten material dispensed from the slotted discharge openings of the nozzle may be varied.

Abstract: A device for applying coolant/lubricant to the surface of the rolls of the rolling mill and/or the workpiece being rolled. The device comprises a housing having a plurality of nozzles associated therewith, a rotating inner manifold having a plurality of apertures therein in a particular array for directing liquid to the nozzles and sealing means between the manifold and housing which provides a leak-free passageway for the liquid. The manifold is rotated to align the apertures therein with the leak-free passageway to supply liquid to the desired nozzles.

Abstract: A coolant nozzle of adjustably variable width stream for a grinding wheel or the like, the nozzle including a hollow housing extending laterally across the working face of the grinding wheel having a coolant inlet in an upper region and a coolant outlet extending laterally in a lower region, a tubular formation extending laterally across the interior of the housing having a coolant receiving opening on its upper side adjacent to one end of the tubular formation and a coolant discharging port configuration on its lower side extending the length of the tubular formation. A control element or closure extends across the tubular formation and is shiftable longitudinally along the tubular formation to communicate the upper receiving port with a selected length of lower discharging port.

Abstract: A variable output nozzle for permitting the output of air or gas from the nozzle to be varied. The variable output nozzle includes a nozzle housing having a bore located therein, a spherical ball located within the bore for reciprocal movement within the bore and an aperture in the nozzle housing for supplying pressurized air or gas to the bore in the nozzle housing. A plurality of slots are also located in the nozzle housing and extend into the upper portion of the bore and the bottoms of at least some of these slots are located at different depths so that the volume of pressurized air or gas exiting the nozzle will vary as the spherical ball passes the bottoms of the slots. The variable output nozzle is particularly useful as a pneumatic pressure transducer nozzle.

Abstract: A fuel injection nozzle for supplying fuel to a compression ignition engine includes a valve member slidable within a bore, a seating in the bore and the valve member being shaped to co-operate with the seating. An extension is carried by the valve member and is slidable in a guide bore extending from the seating to the exterior of the nozzle. The extension has an outlet chamber into which opens a first passage through which fuel can flow as soon as the valve member is lifted from the seating and a second passage through which fuel can flow with increasing quantity as the valve member lifts from the seating. The first passage causes swirling of fuel in the chamber and produces a bushy fuel spray and the fuel flowing through the second passage progressively cancels the swirling to produce a penetrative jet of fuel.

Abstract: A steam desuperheater comprising a liquid spray tube assembly positioned in a steam line and including a plurality of liquid outlet openings supplying liquid to plural spray nozzles, and a hollow piston plug axially movable therein upwardly from a lower valve seat to progressively open said outlet openings.

Abstract: A pinch valve for selectably controlling flow of fluid through one of two resiliently deformable tubes used e.g., for transporting water in a steam iron. The valve comprises a body member defining a compression surface supporting each one of the tubes. A selector lever is pivotally mounted on the body for selectably moving an integral cam abutment between individual tube shut-off positions. A rocker element supported on the tubes is captively held in the body member intermediate the selector lever and the compression surface for rocking movement between tube pinching positions. The cam abutment continually presses on the rocker causing the rocker to bear upon each one of the tubes on the compression surface. As the selector lever is pivoted, the cam abutment engageably slides along the rocker to rock the rocker between its tube pinching positions. The tubes are thus isolated from sliding contact with the cam abutment by the interposed rocker thereby preventing frictional wear of the tubes.

Abstract: The invention relates to a fuel injection nozzle in which a control piston acts on the valve needle, which control piston can also be acted upon by another fluid with an arbitrarily changeable pressure. In this manner it is relatively simple to meet the ever increasing requirements to apply an influence of engine characteristic values to the fuel injection process.

Abstract: A gated irrigation pipe is operated by a pneumatic control system which automatically opens and closes the gates. Each gate is slidable along the pipe surface and is coupled to a pair of parallel air conduits extending longitudinally along the pipe. The conduits are connected midway between their ends to a common movable pneumatic cylinder which receives therein a piston fixed to the exterior of the pipe. The conduits communicate with opposite ends of the cylinder, and serve as both an air line to the cylinder and an operating linkage which opens and closes the gates and which will not cause damage to the gates in response to differentials of expansion and contraction. A plurality of pipes thus equipped are serially connected to form an irrigation pipeline and the air conduits are interconnected at the pipe joints by flexible hose couplings which may be preset any time during each watering interval.

Abstract: The invention relates to fuel injection nozzles for internal combustion engines provided with a nozzle body one end of which includes plural fuel injection spray apertures with plural telescopable valve needles slidably positioned in the nozzle body and arranged to control feed to the spray apertures. At least one valve needle is controllable by an adjusting piston subjected to fuel supply.

Abstract: The invention concerns a fuel injection nozzle with a valve needle and a hollow needle, both of which are loaded by only one spring. During opening one of the needles strikes a stop while the other needle continues to move against the force of the spring.

Abstract: The invention relates to fuel injection nozzles for internal combustion engines provided with a nozzle body one end of which includes plural fuel injection spray apertures with plural telescopable valve needles slidably positioned in the nozzle body and arranged to control feed to the spray apertures. At least one valve needle is controllable by an adjusting piston subjected to fuel supply and plural pressure chambers associated with the respective valve needles permits pressurized fuel supply to successively lift the valve needles independently of the other away from the spray apertures in the nozzle body.

Abstract: A fuel injector for air-compressing, direct-injection internal combustion engines. The injector essentially comprises a nozzle body, a hollow nozzle needle which is axially displaceable therein, and a second nozzle needle which is displaceable within said hollow nozzle needle. The two nozzle needles are controlled in such a way that in the lower speed and/or load range of the internal combustion engine, initially only one nozzle needle opens to release one or some of the spray holes, while the full fuel injection, which may be in different directions, occurs only at full load by opening the other nozzle needle. One of the spray holes is coaxial with the longitudinal axis of the injector, and in the closed and partly opened state of the injector, a pin of the second nozzle needle extends into this hole with clearance.

Abstract: A fuel injector for internal combustion engines having an axially slidable nozzle needle capable of being lifted off its sealing seat by pressure of fuel against at least one spring and having a control pintle below the sealing seat sliding in a blind-hole recess is provided with the improvement comprising a cavity starting immediately below the sealing seat and formed as an eccentric widening extending parallel to the blind-hole type recess, said spray holes opening into said blind-hole type recess and the cross sectional areas of the nozzle seat gap and the cavity at each position of the needle nozzle are greater than the cross sectional area of the at least one spray hole uncovered at any time by the movement of the control pintle.

Abstract: A plunger valve nozzle has a nozzle body with a constant diameter bore extending therethrough, one end of which is open to receive fluid under pressure and has a hollow plunger extending thereinto with a direct acting piston portion slidably fitting the bore and exposed to the fluid pressure through the open end of the bore, there being orifices connecting the interior of the plunger to the periphery of the piston portion which are uncovered by the bore when the fluid pressure is sufficient to move the plunger further inwardly of the bore a predetermined distance, which movement is opposed by a spring connected to the plunger and reacting against the nozzle body.

Abstract: A simple, inexpensive sprinkler head is disclosed which may be adjusted to discharge a fluid in a full circular pattern of variable radius or in a variable size segment of such circular pattern of variable radius. The structure of the sprinkler head, which includes a short tubular body having an array of apertures through the wall thereof forming a closed elipse is described, together with a valve means for adjustment of the radius of the circular pattern of fluid discharge and a movable diaphragm means for adjustment of the size of the segment of the circular pattern in which fluid is discharged. The method of making such structure, including the fabrication of the tubular body of such structure in two parts by casting or molding techniques, is disclosed.

Abstract: An elongated cylindrical housing is arranged to be mounted adjacent to and parallel with the surface of a moving abrasive member and has a row of ports establishing communication between the interior of the housing and its exterior. An elongated cylindrical core member is rotatably supported in the housing and has a spiral groove in its surface of a selected width and pitch such that a small number of ports are exposed to the groove at a time to form a narrow jet. Fluid under pressure is supplied to the groove and upon rotation of the core member the jet of fluid travels across the surface of the moving abrasive member to clean it. A cam is provided in the present apparatus to reciprocate the housing in its longitudinal dimension through a distance approximately equal to the spacing of the ports so that the surface of the abrasive member between the ports is also cleaned.

Abstract: A showerhead of the type including an inlet end, an outlet end, and a bore defining a passage between the two. Two discs are disposed in the passage, in face-to-face engagement with each other and mounted for relative rotation about a central axis. A plurality of orifices, arranged with their centers spaced at regular intervals around a circle of predetermined diameter, extend through each disc. Each orifice of the downstream disc defines a small port at the downstream face and a large port at the upstream face of the disc. Each orifice through the upstream disc defines at its downstream face a port that communicates with but is smaller than a respective port at upstream face of the downstream disc.