US1578092A - Hydraulic jet-dispersal nozzle - Google Patents

Description

March 23 1926. 1,578,092

O. A. PRICE HYDRAULIC JET DISPERSAL NOZZLE F'iled August 28, 1923 2 Sheets-Sheet l j /n's Afromg/s www March 23 1926.

o. A. PRICE HYDRAULIC JET DISPERSAL NozzLE 2 Sheets-Sheet 2 Filed August 28 1923 Patented Mar. 23, '1926.

OWEN ALFRED PRICE, OF KILMARNOCK, SCOTLAND.

HYDRAULIC JET-DISPERSAL NOZZLE.

lApplication filed August 28, 1923.l Serial No. 659,807.

To @ZZ whom t may concern.'

Be 1t known vthat I, OwnN ALFRED PRICE, a Brit-ish subject, and a resident 'of Kilmarnock, Scotland, have invented Certain new and useful improved Hydraulic Jet-Dispersal Nozzles, of which the followingis the specification.

This invention has for its object to provide means for dispersing and cushioningl the destructive energy in high velocity streams of water, and which for instance exists at the outfall of undersluices or discharge regulators for high dams, or in similar casesv where Yhigh level water is freely discharged into comparatively shallow river beds, watercourses, reservoirs, penstock chambers, conduit basins, ponds and the like. l

It has hitherto been the practice to allow such streams or jets to striker the down stream water as solid masses possessing concentrated energy whiclris expended as local shock. Consequentlyvery great damage has been done to the water bed and, due to the swirling currents set up, injury has been done to the masonry and foundations at the Y foot of the dam and to t-he banks and surrounding structures. In the great majority of cases where large high velocity streams are ejected the provision of a `water cushion of .suliicient depth and width to be effectual isa prohibitive undertaking on account of the .great cost of the works. As an alternative, or, in addition to some form of water cushion, it is customary to dump large boulders, blocks of masory and concrete into the water bed and to renew these as they become eroded away orbecome sunk into the water bedby'theeddying and swirling action of the water on the liner material composing the bed. y

i According to the invention means are provided 'immediately adjacent to the nozzle discharge outlet for the creation of one Aor more free'spiral vortices in the stream'immediately before its release to the vatmosphere the means being such that the device may be predeterminedly adapted to the water pressure, its volume and the space available for dispersion. Thus the stream is discharged as one or more conical showers of drops which are cushioned entirely against the atmosphere and scattered as heavy rain drops over a very wide area many hundred times as great as the shock area of the same stream when solid. Whatever velocity and of Vno consequence.

energy is possessed by the solid issuing stream, the dispersed water cannot meet the downstream water at a velocity greater than that of ordinary heavy falling rain, the damaging' effect of which, under the circumstances, is altogether negligible. Local destruction and swirling currents, also are impossible as the delivered water falls in a sheet of drops possessing no penetrating power, and induces a gentle uniform current over the whole width of the downstream bed.

Diffusing nozzles have been proposed in which an inflowing stream is divided into severa-l streams of differently directed motions so asto cause mutual interference and ultimate mixing accompanied by a condition of turbulence.y

Also, in spraying nozzles it has been proposed to produce a flaring discharge by imparting a tangential velocity to the escap-V ing stream, this tangential velocity being produced either by the impact of tangential jets or by helically `ror spirally disposed vanes, the result in either case being to produce a distribution of rotary velocity such that the tangential velocity is directly proportional to the radius, thatfis to say, the angular velocity is constant inany plane at rightl angles to the aXis. Similar devices which produce identically the sameconditions of-velocity distribution in the stream have also beenproposed in connection with Pelton wheel governing, and for dispersing pressure water escaping from relief valves on water turbine supply pipes when the stream lis diverted into confined spaces.

But in vthese cases the jets have been genen ally small in size, and under considerable pressure, thus resulting in very high velocities. The condition atthe outlet orifice has been that of a suddenly released forced vortex, and under these conditions the jetshave been eifectually broken up, while the back pressure'absorbed in the process has been At the same time the ideal conditions necessary for the most economical and most perfect dispersion of the streamhave not been obtained. In application of the present invention, the jets will usually be several feet in diameter and the available heads relatively low. Also on account ofthe totally different objects in view, a perfectly uniform and complete dispersion is required with the consumption of the least possible energy head.

Theoretical considerations suggest, and experiments have demonstrated that if a free-spiral-vortex is allowed to escape freely into the atmosphere the various co-axial free spiral currents of which it is composed cease rotating and pursue a straight'line course. rI`he free vortex condition hereinbefore referred to exists in a fluid flowing axially in a confined space of substantially cylindrical form if it has, combined with the axial component of flow, a tangential component so distributed, across a plane at right angles to the axis, that the said tangential component varies inversely as the radial distance from the axis. By virtue of the free vortex condition each concentric series of currents possesses a different `absolute velocity which is inversely proportional to the distance from the axis, and consequently, each concentric series of currents pursues a different straight line course, those currents nearer the axis, because of their greater velocity, taking a more divergent course, relative to the axis, than those remote from the axis. The result is that the inner currents tend to pass through the outer currents, the released free-vortex becomes a hollow expanding cone of interlacing lilaments to fluid and is rapidly shattered into drops. In this state it is susceptible to the air 'cushioning which is one of the principal objects of the invention.

In carrying out the present invention a nozzle is formed with one or more chambers behind the orifice suitable in shape for the accommodation of a free-spiral-vortex and anterior' to this space apparatus is provided to produce -a'forced-x'fortex of such a type that it most efficiently initiates that free vortex possessing the desired predetermined properties. Various constructions may be adopted according to the size and velocity of the water jet and according as the nozzle is an independent fitting or is combined with a stream-lined valve or other apparatus.

One form of independent nozzle, designed to throw a single hollow cone is preferably constructed of three parts. (l) A divergent conical portion intended to gradually enlarge the area of the stream in order to provide space for the insert-ion of the blading without constricting the free channel. (2) A blade element consisting of radiating vanes with or without a central boss which may have a central passage through it from which the vanes radiate. The vanes are shaped so that they have but a small angle to the normal direction of flow (that is they are at a lesser angle to the axial plane than to the plane of rotation). Their pitch or angular disposition. relative to the axis of the nozzle, gradually becomes less as the distance from the axis increases, thereby imparting a greater tangential velocity to the central. water than to the water nearer the circumference, thus setting up the forcedvortex conditions hereinbefore referred to. It is to be understood however that the rate of change of pitch of the vanes along the radius may be varied. usually convergent and truncated, conical, conoidal, or dome-like providing the space for the consolidation of the natural free vortex and containing a circular outlet orifice in axial line.

In another form intended for a larger stream of water the general design is identical except that an inner Vconoidal shell is Vintroduced dividing the free vortex chamber vinner cone might have a wider angle of divergence than the outer cone so that the inner water would strike the outer water and shiver it more quickly than would be the case if disruption were left entirely to the disintegrating filaments within the hollow cone.

The advantage of throwing more than one cone becomes more valuable as the size of the stream increases, because, witha large jet the discharge cone would have to expand to a very large diameter indeed before it became sufficiently attenuated to become entirely broken into drops. rlChe thickness of the hollow cone at which the water is completely shattered into drops is approximately constant for all sizes of jets and therefore a large stream if dispersed as a single cone, would expand to inconvenient dimensions before this completely shattered thickness was attained. For this reason multiple cones are used as described.

Multiple cones may also be produced by simply dividing the orificel by concentric tubular extensions into two or more b-odies of water. In this case the inner ycones are more divergent than the outer ones because they are supplied with water by the more rapidly rotating portion of the natural free vortex, while the outer cone is supplied b v the more slowly moving annulus. y

then the dispersion nozzle constructed in accordance with the present invention is combined with a stream-lined valve. as already referred to, the conoidal central boss from which the blades radiate and as already described, becomes modified to such proportions as will embrace the operating member of the valve.

And (3) a part Various other constructions may be adopt ed in accordance with the presentjin'vention, the essence of t-he contrivance 'being the comhina-tion in a nozzle of two 4types of vortex, a forced vortex produced by blading of such form that the water leaving it rapidly consolidates itself into a free-vortex of predetern'iined properties, according to the water pressure available, th'evolume to be discharged andthe dispersion space available, this free vortex being formed wit-lun4 aA suitably shaped chamber behind the nozzle orifice so that a perfectly stable freeespiralvortex `is released at the orifice. The disintegration of this vortex when freely ejected allows of the great resistance of the air to act with cushioning effect upon the enormously increased superficial' areaproduced by the perfect shattering' of the stream into uniformly small globules.Y The whole of the destruct-ive energy is therebyrdissipated and no harmful effect can occur at the surface uponwhich the water falls.4

In ano-ther application of the invention, the escaping streams are broken into drops in order to aerate the water for the purposei of improving its quality for town supply purposes and other uses.

Two sheets of explanatory ldrzmvings are hereunto appended in which Figures l to 8, sheet l, are sectio-nal elevations showing somewhat diagrammatically eight examples of the improved nozzle. Figure 9 is a similar view showing the nozzle combined with a. stream-lined valve. The details of the specific construction shown in Fig. 9 are not claimed in this applicationas they form the subject of my divisionaly application, Ser. No. 719,203 filed June. 10, 1924. Figure 10, sheet 2, is a sectional `diagram indicating the course of the free spiral currents formed byfree-vortex action whilst Figures ll and 12 are like views showing how' these currents .cause a divergent conical formation of the stream.

According to the example shown in Figure l the nozzle is designed to throw a single hollow cone of fluid and is constructed of threeV parts. (l) yAn inlet branch A of divergent conical formation intended to gradually enlarge the area of the stream. (2) A blade element composed of vanes B radiating from a central conoidal or stream-lined boss C. These vanes are shaped so that their pitch vor angular disposition relative to the axis of the nozzle gradually becomes less as the distance from the axis increases thereby imparting a greater tangential velocity' tol the central water than to the water nearer t-he circumference. The pitch of the vanes will vary according to the proportion of the work which it is desired thatv the vanesV should accomplish, and the change of pitch' of each vane in a radial direction will vary according to the nature of the fluid being treated and according t-o the surface resistance offered by the particular modification of device adopted, and (3) aconvergent truncated conoidal art D having ay circular outlet orifice in axial line.

This constructionof nozzle therefore produces a forced-vortex, of such form that the lwater rapidly consolidate-s itself into a freevortex within the chamber D and before its release to the atmosphere.

The construction shown in Figure 2 differs from that hereinbefore described in that the divergent conical inlet branch A2 is shortened and made in a piece with the convergent outlet branch D2. The diameter and lengt-h of the central boss C2 is also increased and the pitch of the vanes B2 altered to suit the changed velocity of the fluid produced bythe relatively restricted passage between the boss and the outer wall. The full lines in this ligure show the form of nozzle preferred when used with high pressure fluid and the dotted lines the preferred form for lower pressures.

The designshown in Figure is intended for use in connection with a comparatively large stream of water, In general outline it is similar to the example first hereinbel fore described except that the part forming the free-vortex chamber is of more ycurved form; that is, it diverges outward from the vanes B3 and is convergent towards the outlet orifice; and an inner conoidal shell E3 is introduced dividing the forced and free vortex chambers and the outlet orifice into two parts comprising a central double conoidal r.chamber and an outer annular chamber D3. This conoidal shell E3 is extended outwards beyond the main outlet orifice. lSuch a nozzle throws two coaxial discharge cones and according to the design of the blading B3 these cones may` have equal or different angles of divergence.

The example shown in Figure et shows the application of this inner conoidal .shell E, to L construction very similar to that shown in Figure 2.

Figure 5 differs from the example last hereinbefore described mainly in Athat the inner conoidal shell occupies only the forward portion of the free-vortex chamber D5.

In Figure 6 there is shown a construction which differs from that hereinbefore described practieally only in that the centralv boss CS is of hollow ring form. It has been `found that this ring formation offers less surface friction to the water andeliminates all tendency to cavitation. The centre jet of water passing through the ring is revolved by the large body of water around it, and as no resistance to rotation exists, the centre revolves more quicklyvthan otherwise, and so results in a quicker disintegration. Thc vring itself is employed for llO Il t) (itl construction-al purposes only to hold the ends of the vanes rigidly in position. In small nozzles where the vanes are short and stift the ring may be dispensed with and the vanes simply cut ott leaving a clear central space. This ring construction may be embodied in any of the multiple cone examples shown in Figures 3, 4e and 5 with the same advantageous effects.

rlChe example shown in Figure 'i' differs from that last hereinbeiore described in that, shown in full lines, the free vortex such proportions as t embrace the oper-u atmg member Il. of the valve which, in this example, closes in an upstream direction but may equally well be designed to close in a downstream direction. rlhe free vortex chamber is the predetermining infiuence over the behaviour of the apparatus. The forced vortex chan'iber blades B., have angularly disposed faces imparting the necessary tangential velocities to the stream.

In Figure it will be seen that the free-spiral vortex shown as escaping freely into the vatmosphere comprises various coaxial free spiral currents which have ceased rotating` and pursue a .straight line course. By virtue of the free vortex condition, each concentric series of currents possesses a different absolute velocity which is inversely proportional to the distance from the axis, and consequentl, each concentric series of currents pursues a different straight line course, those currents J nearer the axis, because ot their greater velocity, taking a more divergent course, relative to the axis, than those l remote from the axis. The result is that the inner currents .l tend to pass through the outer currents K, the released freewortex becomes a hollow expandingl cone of interlacing filaments of fluid and is rapidly shattered into drops.

Figure 1l shows how the jet becomes thinned before disruption. ures l0 and 1l. show the jet thrown by the examples hereinbefore described with reference to Figures l, 2, 6, T, S and 9.

Figure l2 shows the two coaxial discharge cones of water thrown from the examples of nozzle described with reference to Figures 3, #l and 5. 0f course it is to be understood that the angles of divergence These two Figof these cones depend upon the pitch of the blading, the inner cone having, as shown, a greater angle of divergence than the outer cone so that the inner water strikesv the outer water and shivers it more quickly than would be the case if disruption were left entirely to disintegration with the l1ollow cone.

That I claim is l. A jet-dispersal nozzle comprising combination and coaxially arranged an let portion, a blade element consisting radiating blades each of a pitch thatY de! creases progressively from the central portion of the stream toward the peripl'iery,

to accommodate a freey spiral vortex, and' all coacting in such manner that the central portion of the stream is revolved with a higher velocity than the peripheral portion, as and for the purposes set forth.

3. A jet-dispersal nozzle comprising in combination and coaxially a divergent inletA portion, a blade element consisting of radiating blades whose pitch variesl inversely with the radius, a central boss and an outlet portion, as and for the purposes set forth.

t. A iet-dispersal nozzle having in combination and coaxially a blade element having means ladapted to impart a greater tangential velocity to the central liquid than to the liquid nearer the circumference, and an outlet portion adapted to form a free spiral vortex.

5. A jet-dispersal nozzle having in combination and coaxially a bladeelement including vanes whose angular disposition relative to the axis of the nozzle gradually becomes less as the distance from the axis increases, and an outlet portion adapted to form a free spiralvortex from theliquid received from the blade element and containing a circular orifice for the jet.

,6. A jet-dispersal nozzle comprising, in combination`v and coaxially arrangethan inlet portion, a blade-element consisting of radiating blades whose pitch varies inversely with the radius, a cent-ral boss having an axial aperture, and an outlet portion.

7. A jet-dispersal nozzle comprising, in combination, and coaxially arranged, an inlet portion, a blade element consisting of radiating blades, whose pitch varies inversely with the radius, adapted to form a forced spiral vortex that Will rapidly con- Solidate to a free spiral Vortex, an outlet portion to accommodate the free spiral vortex, and acentral boss from Which the blades radiate.

8. A jet-dispersal nozzle, comprising, in combination, and coaxially arranged, an in- 10 let portion, a blade element consisting of radiating blades, Whose pitch varies inversely with the radius, adapted torform a forced spiral vortex that Willrapidl7 consolidate to a free spiral vortex, an outlet portion to accommodate the free spiral vortex, andan 15 axially apertured member Within said nozzle.

In testimony whereof I have .signed my name to this specification.

OWEN ALFRED PRICE.

Images