US3319894A

US3319894A - Liquid dispenser

Info

Publication number: US3319894A
Application number: US478599A
Authority: US
Inventors: Rex C Cooprider
Original assignee: Diamond International Corp
Current assignee: Silgan Dispensing Systems Corp
Priority date: 1965-08-10
Filing date: 1965-08-10
Publication date: 1967-05-16
Anticipated expiration: 1984-05-16

Description

y 6, 1967 R. c. COOPRIDER 3,319,894

LIQUID DISPENSER Filed Aug. 10, 1965 I NV EN TOR (EX C COUPE/0E2 BY hu s, ywwfl ATTORNEYS United States Patent 3,319,894 LIQUID DISPENSER Rex C. Cooprider, Hacienda Heights, Califi, assignor, by

mesne assignments, to Diamond international Corporation, New York, N.Y., a corporation of Delaware Filed Aug. 10, 1965, Ser. No. 478,599 13 Ciaims. (Cl. 239-490) This invention relates to improvements in a liquid spray head and in a spray nozzle assembly including same. More particularly, it relates to an improved spray head and spray nozzle assembly of the type in which the liquid spin chamber and its associated swirl and delivery passages are defined at the interface between the inner wall of a socketed spray head and the outer wall of a liquid supply tube fitted into the socket of the spray head, through which the liquid is delivered under pressure for ejection in the form of a spray through an orifice which opens outwardly from the socket to the exterior of the spray head. Such nozzle assemblies and spray heads are exemplified in the US. Patents to Cooprider No. 3,075,708 and to Bretz, J r. Re. 24,981.

In prior nozzles or nozzle assemblies of this type, it has been the general practice to form the spin chamber and its associated swirl and delivery'passages as intercommunicating depressions and/ or grooves either in the wall of the spray head socket or in the exterior wall of the supply tube received in such socket, at areas where such walls of the socket and tube are in sealing engagement with each other. In order to avoid the need for orientation of the spray head and supply tube at the time of their assembly, it has been found necessary as a practical matter to form both the spin chamber and its associated swirl passage or passages as grooves or depressions in the inner wall of the socket in fixed relation to each other and to the spray orifice. The swirl chamber, therefore, has customarily been formed as a circular depression in the inner wall of the spray head socket. This, together with the necessity of having portions at least of the swirl passages extending in other than axial directions, where more than one such passage is employed, has introduced molding problems resulting in limiting of the depth to which such grooves and depressions can be formed by conventional molds and plastic molding procedures. Thus, by limiting the shape and proportions of these important components of the spray nozzle assembly, the performance of same has in turn been limited.

in the same way for practical purposes it has been necessary, where more than a single swirl passage is empioyed, to have all of the swirl passages intersect the spin chamber at locations which coincide along the extended axis of the orifice.

With the foregoing in mind, the primary objects of the present invention are to provide a spray nozzle assembly in which the depth of the spin chamber and its associated swirl passages may be quite substantial without increasing the difficulty of molding or forming either the spray head or its cooperating supply tube; to provide such an assembly in which there may be provided a plurality of swirl passages intersecting the spin chamber at different locations along the extended axis of the spray orifice, to thereby obtain an improved swirling action of the liquid within the spin chamber; to provide an improved unitary molded plastic spray head per se incorporating the advantages above described; and to provide such an assembly in which the components may be readily and accurately assembled in operative relation merely by press fitting or friction fitting them together without necessity for orientation thereof relative to each other.

Thus, in accordance with the present invention, the spin chamber around the inner end of the orifice, as well as all passages leading thereto are formed within the socket of the spray head to open in an outward axial direction toward the mouth of the socket in order to facilitate axial removal of the mold core upon completion of the molding process without limitation of their depth.

In order that the parts may be assembled without necessity for orientation, the socket and the free end portion of the supply tube received therein are formed in corresponding multi-diameter coaxial sections presenting axially-directed shoulders at the junctions of the respective sections. In the assembled relation of parts, both the radially-presented curved surfaces and the axially-presented curved surfaces and the axially-presented shoulder portions of the respective parts have areas in sealing engagement with each other. The said multi-diameter portions or sections of the socket are arranged in inwardlystepped relation with the diameters of said portions, thus decreasing respectively from the outer end toward the blind end of the socket so that the shoulder or shoulders are directed axially outwardly, and both the spin chamber and its associated swirl passage or passages are formed to open outwardly through said shoulder or shoulders in an axial direction, to be closed on their outwardly-opening sides by the cooperating shoulders of the tube. The said spin chamber and passage or passages are placed in communication with the blind or inner end portion of the socket by a groove or grooves which extend radially along the inner walls of the socket, and the radially inwardly-opening sides of said chamber, passages and grooves are closed or sealed by the opposing outer surface portions of the liquid supply tube, In a preferred embodiment, the spin chamber, though formed primarily in the inner wall of the socket section through which the spray orifice opens, intersects the axially-directed shoulder of an adjoining smaller diameter socket section inwardly thereof, whereby a circumferentially extending swirl passage may be defined by an axially-relieved or cutaway portion of the shoulder. Said passage is placed in communication with the inner or blind end of the socket by an axial groove in the inner wall of the socket. Further it is desirable to form a portion of the inner peripheral wall of the chamber concentrically to the orifice and to merge the said swirl passage tangentially with said surface.

In the accompanying drawing and detailed description illustrating the preferred embodiment of the invention, specific words and terms will necessarily be employed in order to promote a clear understanding of the invention. However, it is to be understood that both the draw ings and the detailed description are by way of exemplification only, and that the invention is capable of other and different embodiments, and of changes of its various components without departing from the invention.

In the accompanying drawings:

FIGURE 1 is an exploded perspective view, partly in section, showing the spray head and the upper end portion of its cooperating supply tube;

FIGURE 2 is a section on the line 2-2 of FIGURE 1, and;

FIGURE 3 is a section on the line 33 of FIGURE 1.

Referring now in detail to the accompanying drawing, the spray nozzle assembly therein illustrated comprises a liquid supply tube designated T in its entirety and only the free or delivery end portion of which is illustrated. The said tube defines an internal passage 10 opening outwardly from the free end thereof for delivery of liquid under pressure from any suitable source into the hollow interior of a spray head, generally designated S. The spray head S is of generally inverted cuplike configuration, being formed with a blind socket or recess for snug fluid-tight reception of the free end of the tube T, the arrangement being such that liquid delivered into the blind end of the recess 11 through the tube is conveyed around the end of the tube T and is led to the discharge orifice 12 of the nozzle for discharge therethrough in the form of a spray, by various passages defined at the interface of the respective members S and T, as more fully hereinafter described.

In the instant embodiment of the invention, the spray head S and its associated supply tube T exemplify the components of a spring-projected liquid dispensing pump adapted for application to portable containers for liquids in a well-known manner and as exemplified in the US. Patent to Corsette No. 3,053,459 of Sept. 11, 1962. Accordingly, in the present embodiment, the tube T comprises the reciprocating hollow pump plunger of the dispensing pump, while the spray head S is carried at the upper end of the tube for reciprocation therewith, and is prefearbly provided with an axially-presented finger piece P through which intermittent axial finger pressure may be applied for the purpose of operating the pump to supply liquid under pressure through the tube T into the spray head S for discharge through the orifice 12. For purposes of clarity, the "structure shown in the accompanying drawings is several times the actual size. It will be readily understood that the supply tube T may also exemplify the tubular valve stem of a conventional aerosol or pressurized liquid container or, in fact, any discharge outlet or conduit through which liquid under pressure is delivered to the spray head S.

Considering the parts in more detail, the socket 11 within the spray head is a multi-diarneter socket having a plurality of coaxial interconnected

socket sections

13, 14 and 15, the inner walls of which are of circular cross section. These socket sections are of relatively-decreasing diameter from the open end or mouth 16 to the closed or blind end 17 of the socket. There is thus provided an annular outwardly-presented shoulder 18 at the juncture of the outer socket section 13 and intermediate socket section 14 and a similarly-presented annular shoulder 19 between intermediate socket section 14 and the inner socket section 15. Preferably the inner walls of the respective socket sections are of cylinderical shape, though if desired, they may be of tapered or conical configuration converging inwardly or toward the blind end 17 of the socket.

The mating free end portion of the supply tube T similarly is formed with multiple diameter sections 13t, 141 and 152 respectively increasing in diameter from the free end of the tube and proportioned for snug fluid-tight reception in the respective

mating socket sections

13, 14 and of the spray head. The

shoulders

18t and 19t at the junctures of the respective pairs of sections are axially spaced the same distance as

shoulders

18 and 19 within the socket 11 and are disposed in radial planes with respect to the axisof the tube to make flush sealing contact with the

respective socket shoulders

18 and 19 in the assembled relation of the parts. It is desirable, also, in the preferred embodiment that the engagement of the respective shoulders 18t and 191. with their

counterparts

18 and 19 within the socket limits the insertion of the tube T into the spray head S so as to maintain the free end edge of the tube in spaced relation from the blind end or wall 17 of the socket so that the delivery passages defined respectively by the

axial grooves

20 and 21 in the inner socket wall may open radially into the socket above the free end of the tube T to thus communicate with the tube passage 10.

These delivery passages or passage sections 29 and 21 respectively (hereinafter sometimes designated connecting passages) communicate with

swirl passages

22 and 23 to direct the streams or jets of liquid into a spin chamber 25 which is formed as a recess or depression in the inner socket wall around the inner end of the orifice 12. In accordance with usual practice, orifice 12 extends radially through the said wall for discharge of the liquid in the form of a spray. If desired, the orifice may .4, be surrounded externally by a usual housing or guard 26 constituting an integral portion of the spray head S.

It will be appreciated that but a

single swirl passage

22 or 23 is required in order to produce a satisfactory swirling action by introducing fluid into the spin chamber 25 generally tangentially to the orifice 12, and the invention contemplates the use of but a single such passage where desired. Generally, however, a plurality of swirl passages is desired. An advantageous, though not essential, feature of the present invention consists in location of the

swirl passages

22 and 23 respectively to open into or intersect the spin chamber 25 to deliver jets of liquid thereinto at different depths, or in other words, different locations along the extended axis of the orifice 12, to complement the action of each other and to initiate the swirling action for such proportion of the full depth of the chamber or as may be desired.

Where multiple swirl or

injection passages

22 and 23 are to be em loyed, the orifice 12 is located to extend radially through the medial or intermediate socket section 14 at an axial location midway between the inner and

outer shoulders

13 and 19. Though defined primarily in the intermediate socket portion 14, chamber 25 nevertheless extends inwardly of the socket somewhat across the plane of the shoulder 19 with its inner periphery defined at its inner end by a curved surface or peripheral portion 25a defined by an indentation in shoulder 19 concentric to the orifice 12 and merging with parallel peripheral side wall surfaces 25b. These peripheral walls or surfaces 25b extend axially of the socket and intersect the shoulder 18 so that the chamber 25 opens downwardly or outwardly through the shoulder 13 toward the open end or mouth 16 of the socket 11. The depth of the spin chamber 25 is preferably coextensive with that of the shoulder 18, so that the radially outerface 250 of the spin chamber in effect constitutes an axial extension of the inner surface 13 of the outer socket section.

Clearly the chamber 25 may be of lesser depth if desired. Formation of the chamber in this manner facilitates its formation by a conventional molding process in which the said chamber may be defined by a fixed axial projection of appropriate shape on the mold core, the configuration of the chamber 25 thus making possible the easy withdrawal or stripping of the core regardless of the depth of the chamber 25.

As will be readily apparent, the outwardly-opening side of the spin chamber 25 is closed and sealed by the shoulder 18t of the liquid supply tube. This shoulder 18: is in abutting sealing relation with the opposing shoulder 18 within the socket 11 and a portion thereof extends across the open peripheral side of chamber 25 to form a portion of the peripheral wall of the chamber.

The swirl passage 22 is defined by an axially-relieved or cut-away portion of the socket shoulder 18, the inner axial side of which is defined by the axially-presented surface 22a extending circumferentially between the chamber 25 and the connecting passage 20, in conjunction with the overlying surfaces of tube T. Where this relieved portion extends to the outer radial extremity of the shoulder 18, as in the preferred embodiment, the tube shoulder 181, by its sealing abutment with shoulder 18, closes and seals the outwardly opening peripheral side of the said passage 22 as well as the outer end of the connecting passage 20, while the outer

cylindrical walls

14t and 15t of the tube close the radially inwardly open sides of the chamber 25,

swirl passages

22 and 23, and the connecting

grooves

20 and 21. In the preferred embodiment, therefore, it will be seen that the passage 22 is jointly defined by the spray head S and tube T at their interface both by radially and axially-spaced portions thereof.

However, if the

relieved areas

22 and 23 are defined merely by circumferential grooves or indentations in the axial surface of the

respective shoulders

18 and 19, then such grooves or indentations may be closed solely by the 29 axially-opposed tube shoulders 18! and 19;. It will be noted that with the arrangement herein illustrated, the depth of the swirl passage 22 and its associated connectiug passage 20 could if desired be coextensive with that of the spin chamber 25, though it has not been formed to such full depth in the present embodiment because of the employment therein of the two

such swirl passages

22 and 23 which may be caused to supplement each others action by injecting the liquid into the spin chamber at different depths therein.

In the present embodiment, it "will be noted that the bottoms of the respective groves (on the radially-outer sides thereof) are parallel to the socket axis to facilitate axial withdrawal of the mold core, the axial disposition of the passages 24 and 21, and the axially outwardlydirected open side and end of the

passages

22 and 20 respectively contributing to this also.

For the same reasons, the connecting passage 21 is in the form of a groove of uniform depth in the cylindrical surface of the inner end section of the socket and opens axially outwardly through the shoulder 19. The swirl passage 23 which communicates with the passage 21 is formed in the same manner as passage 22 by a cutaway or axially-relieved portion of the shoulder 19. The said portion is thus relieved axially to provide an offset axial groove wal-l 23a which merges tangentially with the curved inner end wall periphery 25a of the spin chamber and is in a radial plane parallel to the relatively-spaced tube shoulder 192 forming the opposite side wall of the passage 23. As will be apparent from FIGURE 2, the other walls of said groove are defined by the radiallyopposed and spaced

cylindrical surfaces

15 and 15! respectively, it being understood that both the

cylindrical surfaces

13, 13t, 14, MI, 15 and 15t as well as the

shoulders

18, 19, ISI and 19t are in mutually-sealing engagement with each other except at locations where the said surfaces or shoulders are grooved or relieved to form the desired passages at the interface between the members S and T.

In addition to the sealing and passage-defining actions of the above-mentioned shoulders, it will be apparent that the same may be utilized to limit the insertion of the tube T within the socket of the spray head S, so as to maintain the free end of the tube somewhat spaced from the end wall 17 of the socket and thus in effect to provide a distribution chamber 27 at the inner end of the socket, through which fluid or liquid emerging from the tube T isdelivered into the inwardly-opening connecting or delivery passages and 21.

The arrangement is such that in assembling a nozzle in accordance with the invention, the free end portion of the tube T need be merely inserted and pressed into the socketed spray head S, which snugly receives it and may be frictionally retained thereon, though in certain instances it may be desirable to employ more positive retention means of a conventional nature such as threaded interconnections, snap fitting, cementing, of the like.

In the operation of the invention, the liquid delivered under pressure through the tube T and into distribution chamber 27 enters the radially inwardly-opening portions of the

grooves

20 and 21 between the free end of the tube T and the end wall 17 of the socket. It is then delivered through the connecting passages 29 and 21 into the

swirl passages

22 and 23 respectively which inject it at high velocity into the spin chamber from opposite sides thereof and generally tangentially to the spin chamber and its orifice 12 to promote a rapid spinning action about an axis coincident with the orifice, so that as the rapidly-rotating liquid is discharged through the centrally-loca-ted orifice 12, its centrifugal force will cause it to expand radially in all directions about its line of discharge to thus form a fine spray pattern.

It will be readily apparent that the spray nozzle assembly of the invention is adapted for easy and economical fabrication by molding and for ready assembly without necessity for relative orientation of the parts. Also, be-

cause of the specific arrangement of the various passages and the spin chamber of the spray head, these may be formed of substantial depth by conventional plastic molding processes and apparatus without difiiculty.

In this application, there is shown and described only the preferred embodiment of the invention. However, it will be appreciated that the inventive ideas and concepts disclosed herein are capable of embodiment in other forms and for other purposes and that various of the elements and details thereof may be omitted or changed, all without departing from the invention. Also, it will be appreciated that the spray head per se as well as in combination with the supply tube is included in the invention.

Having thus described my invention, I claim:

1. A unitary spray head formed with a socket having coaxial sections of circular cross section, which sections are of successively increasing internal diameter from the blind end toward the open end of the socket, axially outwardly-presented annular inner and outer shoulders being provided between adjoining sections, the spray head being formed with a spray orifice opening in a generally radial direction from its socket to its exterior at an axial location medially between said shoulders, and a spin chamber in the form of a depression around the inner end of said orifice, said spin chamber having one peripheral side opening axially through said outer shoulder toward the open end of the socket, said chamber intersecting and extending axially into said inner shoulder, said inner shoulder having a concave depression concentric to said orifice defining an inner peripheral wall portion of the chamber, the balance of said peripheral wall being defined by parallel axially-extending sides of said chamber, said spray head being formed within said socket and on opposite sides of the spin chamber with radially inwardly-opening axial depressions spaced circumferentially from the chamber and each opening axially outwardly through one of said shoulders, said shoulders respectively being formed with axially-inward indentations extending circumferentially of the socket from each said last-mentioned depression into said chamber.

2. A spray nozzle assembly including a unitary spray head as defined in claim 1, in combination with a liquid supply tube the supply passage of which opens through its terminal end, and the terminal end portion of which comprises relatively-coaxial adjoining sections of relatively-decreasing diameter toward said terminal end, said tube sections being received in the respective multi-diarneter sections of the spray head socket in radial sealing engagement therewith to define the radially inner walls of the spin chamber, and depressions, said tube having axially-presented shoulders at the junctures of the respective adjoining tube sections in sealing engagement with the respective shoulders in said socket and closing the outwardly-open side portions of said spin chamber and dep-ressions.

3. A unitary spray head formed with a socket having coaxial sections of circular cross section, which sections are of successively-increasing internal diameter toward the open end of the socket, axially outwardly-presented annular inner and outer shoulders being provided between adjoining sections, said spray head being formed with a spray orifice opening in a gene-rally radial direction from said socket to the exterior thereof at an axial location medially between said shoulders, and with a spin chamber in the form of a depression around the inner end of said orifice, said chamber axially intersecting both said shoulders and having one peripheral side thereof opening axially outwardly of the socket through said outer shoulder, one of said shoulders being formed in its axiallypresen-ted surface with an axially relieved area communicating with said chamber, said area extending circumferentially from the chamber for a portion only of the circumference of the socket and opening axially outwardly through said one shoulder, the socket section immediately inwardly of said one shoulder being formed with a radially inwardly-opening axial groove intersecting said area at its outer end and extending therefrom toward the inner end of said socket to a location spaced axially inwardly of both said shoulders.

4. -A unitary spray head formed with a socket having coaxial sections of circular cross section which sections are of successively-increasing internal diameter toward the open end of the socket, axially outwardly-presented annular inner and outer shoulders being provided within the socket between adjoining said sections, said spray head being formed with a spray orifice opening in a generally radial direction from said socket to the exterior of the spray head at at location between said shoulders, and with a spin chamber in the form of a depression around the inner end of said orifice, said spin chamber opening axially through said outer shoulder toward the open end of the socket and intersecting said inner shoulder, said inner shoulder having formed in its axiallypresented surface an indentation extending circumferentially from said chamber, said spray head further being formed within said socket with a radially inwardly-opening axial groove intersecting said indentation and spaced from said chamber, said groove extending axially inwardly through said inner shoulder.

5. A unitary spray head formed with a socket having coaxial sections of circular cross section Which sections are of successively-increasing internal diameter toward the open end of the socket, axially outwardly-presented annular inner and outer shoulders being provided between adjoining said sections, said spray head being formed with a spray orifice opening outwardly from said socket to the exterior thereof and with a spin chamebr in the form of a depression around the inner end of said orifice, said spin chamber extending between and axially intersecting said shoulders to open axially outwardly through said outer shoulder and to have its inner end closed by a portion of said inner shoulder, said outer shoulder having an axially relieved portion extending circumferentially into said chamber to define a swirl passage, and said spray head being provided with means for delivering pressurized liquid into said indentation at a location remote from said chamber.

6. A unitary spray head formed with a socket having coaxial sections of circular cross section which are of successively increasing internal diameter toward the open end of the socket, an axially outwardly-presented annular shoulder being provided between adjoining said sections, said spray head being formed with a spray orifice opening in a generally radial direction from said socket to the exterior of the spray head and axially displaced from said shoulder, and with a spin chamber in the form of a depression around the inner end of said orifice and intersecting said shoulder, said shoulder being formed with a generally circumferentially extending axially relieved area communicating with said chamber and extending therefrom for a portion only of the circumference of the socket, to define a swirl passage and with an axial groove intersecting and terminating at said relieved area at a location remote from said chamber, to provide a connecting passage between said swirl passage and the inner end of the socket.

7. In combination with a spray head as defined by claim 6, a liquid supply tube having a free end portion of reduced external diameter relative to that of the adjoining tube portion remote from the free end of said tube, said free end reduced diameter portion being received in sealing engagement with said socket wall around said chamber and said passage to close the radially inwardlyopening sides thereof, and having an axially inwardlypresented shoulder in sealing engagement with said shoul- O n der of the spray head for closing the axially outwardlyopening sides of said chamber and swirl passage.

8. The combination defined in claim 7 in which said shoulder limits the axial insertion of said tube into said socket to maintain the free end of the tube in axiallyspaced relation from the end of the socket, said axial groove in the socket wall extending inwardly of the socket to a location between said free end of the tube and the inner end of the socket and communicating with the said tube.

9. In combination with a spray head as defined in claim 6, a liquid supply tube having a free end portion received in the socket of said spray head in peripheral sealing engagement with the inner walls of said socket to close the inwardly-opening sides of the said passage and spin chamber, and having an axially inwardly-presented annular shoulder in sealing engagement with said shoulder of the spray head to close the axially-opening sides of said chamber and passages.

10. A unitary spray head as defined in claim 6, in which said shoulder is located axially inwardly of the said orifice and defines an inner peripheral wall portion f the said chamber, the relieved area opening into the spin chamber through said peripheral wall portion.

11. A unitary spray head as defined in claim 10, in which said inner peripheral portion defined by said shoulder is in the form of a curved indentation concentric to the orifice o fthe spray head, and the inner surface of said relieved area merges tangentially with said curved surface.

12. A unitary spray head as defined in claim 6 in which said spin chamber is located inwardly of said shoulder and opens axially therethrough.

13. A spray head formed with a socket having coaxial sections of circular cross section, which sections are of successively increasing internal diameter toward the open end of the socket, axially outwardly-presented inner and outer shoulders being provided between adjoining sections, such spray head being formed with an orifice opening outwardly thereof from said socket from a location between said shoulders, and with a spin chamber in the form of a radially inwardly-opening depression around the inner end of said orifice, said chamber axially intersecting the respective shoulders and being of a radial depth no greater than that of said outer shoulder to open outwardly through said shoulder toward the open end of the socket, said inner shoulder being formed with an axially-inward indentation communicating with the spin chamber and extending circumferentially therefrom from a portion only of the circumference of the socket, in combination with a liquid supply tube having a free terminal end portion received in said socket and in spaced relation to the inner end of the socket, said terminal end portion having coaxial sections of successively-decreased diameter toward its terminal end and in snug sealing engagement with the inner peripheries of said respective socket sections, said tube including an axially inwardlypresented annular shoulder in axial sealing engagement with the said outer shoulder of the socket to close the outwardly-opening side of said chamber, and a further shoulder abutting against said inner socket shoulder to close the inner end of the chamber and to coact with said indentation of the inner shoulder in providing a closed swirl passage communicating with the chamber, said tube and said spray head jointly defining means for establishing communication between the tube interior and said swirl passage.

No references cited.

EVERETT W. KIRBY, Primary Examiner.

Claims

5. A UNITARY SPRAY HEAD FORMED WITH A SOCKET HAVING COAXIAL SECTIONS OF CIRCULAR CROSS SECTION WHICH SECTIONS ARE OF SUCCESSIVELY-INCREASING INTERNAL DIAMETER TOWARD THE OPEN END OF THE SOCKET, AXIALLY OUTWARDLY-PRESENTED ANNULAR INNER AND OUTER SHOULDERS BEING PROVIDED BETWEEN ADJOINING SAID SECTIONS, SAID SPRAY HEAD BEING FORMED WITH A SPRAY ORIFICE OPENING OUTWARDLY FROM SAID SOCKET TO THE EXTERIOR THEREOF AND WITH A SPIN CHAMBER IN THE FORM OF A DEPRESSION AROUND THE INNER END OF SAID ORIFICE, SAID SPIN CHAMBER EXTENDING BETWEEN AND AXIALLY INTERSECTING SAID SHOULDERS TO OPEN AXIALLY OUTWARDLY THROUGH SAID OUTER SHOULDER AND TO HAVE ITS INNER END CLOSED BY A PORTION OF SAID INNER SHOULDER, SAID OUTER SHOULDER HAVING AN AXIALLY-RELIEVED PORTION EXTENDING CIRCUMFERENTIALLY INTO SAID CHAMBER TO DEFINE A SWIRL PASSAGE, AND SAID SPRAY HEAD BEING PROVIDED WITH MEANS FOR DELIVERING PRESSURIZED LIQUID INTO SAID INDENTATION AT A LOCATIONS REMOTE FROM SAID CHAMBER.