Note: Descriptions are shown in the official language in which they were submitted.
877
INTERCHANGEABLE NOZZLE APPARATUS FOR
FULL OR PART CIRCLE IRRIGATION SPRINKLERS
TECHNICAL FIELD
This invent on relates generally to nozzles for
lrrigation sprinklers, and, more particularly, to an inter-
changeable nozzle for selectively varying the size and shape
of the outlet orifice of such sprinklers.
BACKGROUND OF THE PRIOR ART
As is well known in the art, it is highly desirable
for an irri~ation sprinkler, partlcularly of the so-called
large gun type, to be provlded with a means for varying the
size and shape of the outlet orifice of the sprlnkler so
that the user of the sprinkler may selectively vary the
characteristics of ~he flow of water emitted by the sprink-
ler according to, for example, varying seasonal requirements.It may be desired, for example, to control the flow rate
the water emitted ~rom the sprinkler, to control the dis-
tribution of water over the range of throw of the sprinkler~
or to enhance the range of throw of the sprinkler when
water i~ supplied to the sprinkler at relatively low
pressures .
One way in which this has been accomplished is by
providing the large gun type sprinklers with a set of inter-
changeable orifice rings which may be secured to the dis-
charge end of a generally frusto-conical houslng mounted on
the dis¢harge tube of the sprlnkler. The~e rings restrict
the discharge orifice and reduce the flow rate through the
sprinkler.
Another method ~or varying the shape of the outlet
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Or such a sprinkler is to mount a housing on the discharge
tube of the sprinkler which has the desired shape formed
integrally at its ~tlet. The desired shape may be, ~or
example, a converging frusto-conical outlet for enhancing
the distribution of water over a relatively short range of
throw, or a substantially stralght bore outlet ~or enhancing
the range of throw of a sprinkler when operated at a
relatively low supply pressure.
Although these methods function satisfactorily,
if it is desired to vary the size as well as the shape o.
the outlet, a separate unit, including housing and outlet,
must be provided for each combination of size and shape
desired. Moreover, the houslngs of all of the above de-
scribed nozzle arrangements are sub~ected to the highly
abraslve flow of water through the sprinkler which adversely
affects their wear life. The cost of providing a separate
nozzle, including housing and outlet, for every combination
of size and shape desired, when added to the co~t of
periodic replacement of these nozzles, signlficantly in-
creases the cost of operating an irrlgatlon system.
In part-clrcle applicatlons, a reactlon drive type
sprinkler ls rotatably driven by a reaction arm in a flxst
direction about a vertical axis in a manner well known in
the art. When the sprinkler has been rotated through a
pre-selected arc, a camming mechanism operates to move a
reverse drlve arm, thereby placing a reverse deflector
spoon in the stream of water ejected from the sprinkler.
The reaction ~orce created by the stream of water impinging
on the deflector spoon rotates the sprinkler in a reverse
direction back through the same pre-selected arc, and at the
other end of the arc, the camming mechanism operates to
move the deflector spoon out of the stream of water and
normal operation of the sprinkler in the first direction is
resumed. One sprinkler of the foregoing general type is
the Model 103 Rain Gun manufactured by Rain Blrd Sprinkler
Mfg. Corp., of Glendora, California.
If the reverse deflector spoon moves too far into
the stream, the resulting higher reaction force on the
spoon can rotate the sprinkler vary rapidly in the reverse
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directiong thereby causing increased wear and possible damage
to the sprinkler. To avoid this possibility, reverse drive
arms have been provided with a means for adjusting the
extent to which the reverse deflector spoon enters the
stream. Although the mechanisms provided for this purpose
function satisfactorily, whenever the nozzle size i~ changedJ
as described above, it is necessary to read~ust the reVerse
drive arm to achieve proper reverse rotational speed of
the sprinkler.
Accordingly, there has existed a need for a con-
venient and effective devlce for varying the size and shape
of the outlet orifice of a sprinkler, particularly of the
large gun type, which is relatively inexpensive to manu-
facture and does not sub~ect its housing to the abrasive
15 ~low of water through the sprinkler. Further, there exists
a need for a sprinkler of the foregoing type which includes
some means associated with its reversing mechanism for
automatically compensating for nozzles of different sizes.
As will become apparent from the following~ the present
20 invention satisfies these needs.
BRIEF SUMMARY OF THE INVENTION
The pre~ent invention resides in a ne~ and improvad
nozzle for uae in irrigation sprinklers, primarily of the
large gun type, and by whlch the sizes and shape of the
25 outlet ~ the sprinklers may be selectively varied by inter-
changeably retaining a plurality of nozzle insert members
in a single housing attached to the discharge end of the
sprinkler. When used in combination with part-circle
sprinklers, each insert member is arranged to cooperate with
30 the reverse drive arm of the sprinkler so that the operative
position of the reverse deflector spoon is automatically
ad~usted to provide the desired reverse rotational speed
of the sp~rinkler. Moreover, the nozzle of the present
invention is relatively inexpensive to manufacture, is
35 trouble-free and reliable in use) and attaine its advan_
tageous result without sub~ecting the housing to the abra-
alve flow o~ water through the sprinkler.
More specifically, the nozzle of the present in-
vention includes a housing which is secured to the outlet
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end of the sprinkler and extends outwardly from the
sprinkler. All o~ the interchangeable nozzle inserts are
of the same exterior size so that they fit uniformly in the
same housing and are held firmly in the housing by the same
retalning collar. The inlet of each of the inserts has a
diameter which matches the diameter of the discharge end
of the sprinkler, and the oùtlet of each of the inserts may
be of any smaller diameter.
The inner wall of one set of inserts which defines
a passage from the inlet to the outlet can decrease in
diameter ak a constant rate through the insert thereby
forming a converging frustoconical surface for enhancing
the rapid breakup of a stream of water ejected from that
insert. The inner wall of another set of inserts can de-
crease in diameter at a constant rate to a desired diameterand then provide a region of con~tant diameter, or a straight
bore portion adJacent the outlet. This type of insert can
be selected for achieving an enhanced range of throw over
the range achieved by the aforementioned frustoconical
insert.
The inner wall of yet another set of lnserts can
decrease in diameter at a radually decreasing rate from the
inlet to the outlet and end in an asymptotic portion which
approaches a substantially straight bore outlet. A stream
of water flowing through such an insert ~s gradually re-
duced in diameter and passes smoothly into the asymptotic
portion of the insert ~mediately before being emitted from
the nozzle, thereby causing the stream to be highly colli- -
mated and achieving an enhanced range of throw when water
iæ supplied to the sprinkler at relatively low pressures.
For use in connection with part-circle sprinklersJ
the insert member can include an axially extending portion
ad~acent its outlet end and projectlng outwardly from the
nozzle housing. For limiting the movement of the reverse
deflector spoon into the stream of water e~ected from the
sprinklerJ an ad~ustable stop is provided on the reverse
drive arm in a position for abutting the extending portion
of the insert member when the reverse deflector spoon is
moved into the stream. In this way, the operative ~sition
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of the reverse deflector spoon is automatically adjusted
to provide substantially the same reverse rotational speed
of the sprinkler regardless of the size ~ the nozzle being
used.
Alternatively, the housing may be adapted for use
wlth conventional ring orifice devices by placing a liner
insert in the housing to protect the housing from wear, and
securing a ring orifice to the outlet ~nd of the housing
uslng the same retaining collar used to secure the other
sets of interchangeable inserts within the housing. The
liner insert has an inlet diameter which matches the diame-
ter ~f the discharge end of the sprinkler, and the inside
diameter of the liner insert decreases along its length
for directing the stream of water flowing through the nozzle
15 toward the discharge aperture in the ring orifice. When
this arrangement is used in connection with a part-circle
sprlnkler, an axially extending portion can be secured to
the ring orifice for projecting outwardly from the nozzle
housing and cooperating wlth the stop on the reverse drive
20 arm in the same manner as described above.
Other features and advantages of the present in-
ventlon wlll become apparent from the followlng detailed
descrlptionS taken ln con~unction with the accompanying
drawlngs, which lllustrate~ by way of example, the prln-
25 ciples ~ the lnventlon.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE 1 is a perspective vlew ~ a nozzle assemblyembodying the present invention~ and illustrated assembled
on a conventlonal sprinkler ~ the large gun reaction drive
30 type;
FIG. 2 is an enlarged, fragmentary~ cross-section-
al vlew of the nozzle assembly of the present inventlon
taken substantlally along line 2-2 of FIG. 1, and illus-
trated wlth a power nozzle type insert;
FIG. 3 is a perspective view of the lnsert
shown ln FIG. 2;
FIG. 4 is a perspective vlew of an insert similar
to t~at shown in FIG. 3) but having a smaller outlet
diameter;
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FIG. 5 is an enlarge~, fragmentaryg cross-sectional
view Or the nozzle assembly of the present invention, taken
substantially along line 2-2 of FI~. 13 and illustrating a
frustoconical type insert;
FIG. 6 is an enlarged, fragmentary, cross-sectlonal
view of the nozzle assembly of the present invention, taken
substantially along line 2-2 of FIG. 1, and illustrating a
straight bore type insert;
FIG. 7 is an enlarged, fragmentary; cross-sectlonal
10 view of the nozzle assembly of the present invention~ taken
substantially along llne 2-2 of FIG. 1, and illustrating a
liner insert for uæe with a conventional ring ori~ice;
FIG. 8 is a perspective view of a nozzle assembly
of an alternative em~odiment o~ the present invention, and
15 illustrated assembled on a conventional part-circle sprink-
ler of the large gun reactinn drive type;
FIG. 9 is an enlarged fragmentary view, partly
in section, showing relevant detail of the nozzle assembly
and reverse drive arm construction of the sprinkler
20 FIG. 8; and
FIG . 10 is an enlarged, fragmentary, cross-
sectional view) similar to the view of FIG. 9~ and illus-
trating the ring orifice assembly of the present invention
adapted for use in connection with a part-circle sprinkler.
DETAILED D~SCRIPTION OF.THE INVENTION-
As shown in the exemplary drawings, the present
inventlon is embodied in a nozzle assembly for use with an
lrrigation sprinkler of the impact or reaction drive type,
and herein is shown in the drawlngs as a large gun reaction
- 30 drive type sprinkler, indlcated generally by reference
numeral 1~ in FIG. 1. . In this instance, the sprinkler 10
ls mounted for rotation about a vertical axis on a water
; supply pipe 12, and includes a rotational bearing portion
14, an elbow 16, and a range tube 18 through which water
travels to a nozzle, indicated generally by reference
.` numeral 20.
When in use; water is admitted under pressure
into the sprinkler 10 through the supply pipe 12, and
travels through the elbow 16 and the range tube 18 to the
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nozzle 20. The nozzle 20 ejects the water upwardly and
outwardly away from the sprinkler 10~ the distance of throw
being a function of nozzle size, the supply pressure of the
water admitted to the sprinkler~ and the degree of colli-
5 matlon of the stream of water ejected rrom the nozzle.
To drive the sprinkler 10, a reaction arm 22herein is mounted for rotation about a horizontal axis on
a pln 24 extending from a boss 26 on the range tube 18.
The arm 22 includes, at o ne end, an inner water deflecting
10 portion 28 and an outer water deflecting porkion 30, and a
counter weight 32 disposed at its ot; er end.
During the operation of the sprinkler 10, the
water def lecting portions 28 and 30 intermittently enter
the stream of water emitted from the nozzle 20 and deflect
15 a portion of the stream of water laterally. The reaction
to the force required to deflect that water is imposed on
the boss 26 through the arm 22 therehy imparting to the
sprinkler 10 an increment of rotational movement. The
operatil~n of the reactlon arm 22 to drive the sprinkler 10
20 is well known in the art, and it is not believed necessary
to describe that operation in detail here.
W~hen arranged for part-circle operati~n, as can
best be seen in FIG. 8, the sprinkler 10 ' includes a
reverse drive arm 80. The part-circle sprinkler illus-
25 trated in exemplary FIGS. 8 through 10 is substantially likethat previously discussed in connection with FIG. 1, and
parts of the sprinkler of FIGS. 8 through 10 which find
substantial correspondence in structure and function to
those previously discussed in connection with FIG. 1, have
30 been designated with corresponding primed referenced
numerals.
In operation of the part-circle sprinkler 10 1,
the drive arm 22' operates to drive the sprinkler 10 '
through a preselected arc in the same manner as described
35 above in connection with the full-circle sprinkler 10 of
FIG. 1. In order to confine the sprinkler 10 ' within the
preselected arc, the re~-rse drive arm 80 is arranged to
return the sprinkler 10 ' back through the preselected arc,
whereupon the drive arm 22 ' resumes operation for rotating
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the sprinkler in the forward direction.
Toward this end~ the re~erse drive arm 80 is also
mounted for rotation about a horizontal axis on a pin 24 l
secured to a boss 26 ~ on the range tube 18'. The reverse
drive arm 80 extends above and generally parallel to the
nozzle 20 ~, and has a reverse deflector spoon 82 at its
outward end.
When the reverse deflector spoon 82 ls lowered
into the stream of water e~ected from the nozzle 20 ~, the
10 reaction force created by the water impinging on the spoon
82 acts on the sprinkler 10~ through the reverse drive arm
80 and boss 26 ~ to rotate the sprinkler 10' in a reverse
direction until the spoon 82 is removed from the stream.
For rotating the reverse drive arm 80 about the
pin 24 ~, thereby moving the reverse deflector spoon 82 into
and out of the stream of water ejected from the nozzle 20 l,
a downwardly depending crank 84 is mounted for rotation wlth
the reverse drive arm 80 . Pivotally attached to the lower
end of the crank 84 is a connecting rod 86 which extends
20 along the ran~e tube 18' and is pivotally attached at its
other end to the upper corner 88 of a generally triangular
plate 90 whlch i~ pivotally secured at its lower forward
corner 92 to the elbow 16'. The lower rear corner 94 of the
trlangular plate 90 is arranged with a roller-type cam
follower 96 which is movable upwardly or downwardly by
camming surfaces 98 and 100, respectively. The surfaces 98
and 100 are formed on a pair of cam brackets 102 and 104
that are releasably secured to a flange 105 so that the
brackets 102 and 104 can be located at any desired circum-
ferential position on the flange 105.
In operation of the mechanism for moving thespoon 82 into and out of the stream e~ected from the nozzle
20', as the sprinkler 10' is rotated by the drive arm 22~
toward the end of the preselected arc, the camming surface
100 moves the cam follower 96 downwardly, rotating the
triangular plate 90 in a counter-clockwise dlrection. The
connecting rod 86 is thereby drawn inwardly, away from the
: nozzle 20', rotating the crank 84 in a clockwise direction
and moving the spoon 82 into the stream. With the spoon 82
.'
in the stream9 the sprinkler lO' rotates in a reverse
direction back through the preselected arc until the cam
follower 96 is moved upwardly by the camming surface 98.
Upward movement Or the follower 96 rotates the plate 90 in
a clockwise direction, moving the connecting rod 86 out-
wardly toward the nozzle 20', rotating the crank 84 in a
counterclockwise direction, and removing the spoon 8~ from
the stream, thereby permitting the sprinkler lO' to resume
normal forward rotation under the influence of the drive
arm 22'.
In accordance with the present invention, the
nozzle 20 of the sprinkler 10 includes means for selectively
varying the size and shape of the outlet from the sprinkler
10 by interchangeably retaining a plurality of nozzle insert
members 34 ln a single housing 36 of the nozzle 20 which is
attached to the discharge end of a range tube 18. Moreover,
when used in connection with part-circle sprinklers, each
insert member is arranged to cooperate with the reverse
drlve arm 80 of the sprinkler so that the operative posi-
tion of the reverse deflector spoon 82 is automatically ad-
~usted to provide the de~ired reverse rotational speed of
the ~prinkler regardless of the size of insert member being
u~ed.
Further, the nozzle 20 of this invention is rela-
25 tively inexpensive ~ manufacture, is trouble free andrellable in use, and the housing 36 of the nozzle 20 is not
sub~ect to abrasion by the water flowing through the
sprinkler lO.
In order to conveniently vary the size and shape
of the outlet from the sprlnkler, the nozzle 20 is com-
prised of a single housing 36 which is arranged to receive
interchangeably any one of a set of insert members 34. As
will be described in greater detail hereinafter, the insert
members 34 can be comprised of any desired shape and can
35 provide the sprinkler 10 wlth an outlet of any desired size
smaller than the discharge end of the range tube 18. To
enhance the wear life of the nozzle 20~ the insert members
can be conveniently and economically molded of an abrasion
resistant polyurethane material.
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Toward the foregoing ends, the nozzle 20 is com-
prised of a generally cylindr~cal housing 36 which is
threadably received over the discharge end of the range
tube 18 and extends outwardly therefrom. The insert member
5 34 is held within the housing 36 by a collar 38 which is
threadably received over the outward end of the housing 36
and includes inwardly extending portions 40 which bear
against a shoulder 42 on the insert member 34~ thereby
holding the insert member 34 within the housing 36, and
10 forming an abutting waterseal between the discharge end of
range tube 18 and the insert member 34.
The range tube 18 has an internal passage 44
through which water flows from the sprinkler 10 to the
nozzle 20, and the insert member 34 has an inlet 46 and
15 an outlet 48 for receiving and ejecting the stream of water
as it flows through the nozzle 20. In order to smoothly
receive the stream of water flowing through the passage 44,
the insert member 34 is held within the housing 36 80 that
the lnlet 46 abuts the discharge end of range tube 18, and
the inslde diameter of the inlet 46 is substantially equal
to the insl~e diameter of the passage 44 at the discharge
end of range tube 18.
The insert member 34 includes an lnner wall 50
which defines a passage 52 extending through the insert
25 member 34 from the lnlet 46 to the outlet 48. As seen in
FIG. 2, the inner wall 50 converges toward the center of
the insert member 34, and the rate of convergence of the
inner wall 50 gradually decreases along the length of the
insert member 34 from the inlet 46 to the outlet 48 thereby
30 forming an asymptotic portion 54 of the passage 52 ad~acent
the outlet 48. The asymptotic portion 54 is nearly parallel
to the axis of the insert ~mber 34 and therefore deflnes a
substantlally straight bore outlet.
An insert member 34 having an inner wall 50
35 defining any desired conflguration of the passage 52 may
be interchangeably disposed within the housing 36 by re-
moving the retaining collar 38, sliding the insert member
34 out of the outward end of the housing 36~ and reassemb-
ling the nozzle 20 using an insert member 34 having the
--1 1--
desired configuration. Toward this end~ as can best be
seen in FIGS 3 and 4, the insert member 34 is provided
with longitudinally extending ribs 56 which extend from a
point adjacent the inlet 46 toward the outlet ~8 and end
forming the shoulder 42. To hold the insert member 34
firmly in place when it is disposed in the housing 36, each
of the ribs 56 has an outer surface 58 which is arranged
to bear against the inner surface 60 of the housing 36.
All of the inserts 34 are provided with ribs 56 having
10 surfaces 58 which cooperate with the inner surface 60 of
the housing 36 so that each insert 34 fits uniformly withln
the same housing 36. However~ the various interchangeable
inserts 34 can have outlets 48 of different diameters for
varying the flow rate of water emitted from the sprinkler
15 10.
As can best be seen in FIGS. 5 and 6, an insert
member 34 ~ may be provided having an inner wall 50' which
defines a passage 52' of any desired shape. In these
examples, the nozzle 20' is substantially like that pre-
viously discussed in connectlon with the nozzle of FIGS. 1through 4, and parts of the noæzles of FIGS. 5 and 6 which
find substantial correspondence in structure and function
to those previously discussed in connection with FIGS. 1
through 4, have been designated with corresponding primed
reference numerals. It should be noted that the range tube
18~ housing 36 and retaining collar 38 have not been desig-
nated with primed reference numerals because these parts
are identical to those illustrated in exemplary FIGS. 1
through 4.
As can best be seen in FIG 5~ the insert member
34 ~ has an inlet 46 ~ having an inside diameter substan-
tially equal to the inside diameter of the passage 44 at
the discharge end of the range tube 18, and the wall 50'
converges toward the center of the insert member 34 l at a
35 constant rate unt~l the wall 50 ~ defines a ~assage 52'
having thb desired diameter. Thereafter, the wall 50'
maintains a constant diameter thereby providing a straight
bore portion 61 adjacent the outlet 48 ~ .
The nozzle 20 can further be adapted for use with
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conventional ring orifice devices. As can best be seen in
FIG. 7, an insert member 62~ which can also be molded of
an abrasion resistant polyurethane material; is disposed
within the housing 36 and bears against the inner wall 60
of the houslng 36~ and a conventional orifice ring 64,
having a water discharge aperture 66~ is held against the
end of the insert member 62 by the collar 38. The insert
62 has an inlet 68 having an inside diameter substantially
equal to the inside diameter of the passage 44 at the dis-
10 charge end of range tube 18, and an outlet 70 having aninside diameter greater than the diameter of the discharge
aperture 60 of the orifice ring 64. The orifice ring 64
may be interchàngeably replaced by another orifice ring 64
having a discharge aperture 66 of a different diameter
15 thereby allowing the user to selectively vary the flow rate
of water emitted by the sprinkler 10.
In accordance with an alternative embodiment of
the invention arranged for use with a part-circle sprinkler
10', such as that illustrated in exemplary FIG. 8, the
20 nozzle 20' is provided with an insert member 3~' having an
axially extending portion 106 ad~acent its outlet 48 l and
pro~ecting outwardly from the nozzle housing 36'. The
insert member 34 ~ is retained within the housing 36 ' in the
same manner discussed in connection with the sprinkler of
25 FIGS. 1 through 7. That is, the insert n~mber 34 ' is held
within the housing 36 l, with its inlet 46' abutting the
discharge end of the range tube 18 ~, by the collar 38 ' .
For limiting the movement of the reverse deflector
spoon 82 into the stream of water ejected from the sprinkler
3 10', an adjustable stop 108 is provided on the reverse
drive arm 80 in a position for abutting the extending por-
tion 106 of the insert member 34 l when the reverse deflector
spoon 82 is moved into the stream. As can best be seen in
FIG. 9, the adJustable stop 108 includes an externally
threaded shaft 110 having a generally flat head 112 at its
lower end for bearing against an exterior surface 114 of
the projecting portion 106. The shaft 110 is recelved in
an internally threaded bore in a boss 116 formed on the
reverse drive arm 80 and the shaft includes an open slot 118
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at its upper end for receiving the blade of a screwdriver
(not shown) which can be used to adjustably locate the stop
108 in any desired position with respect to the boss 116.
l~y this arrangement, the extent to which the re-
5 verse deflector spoon 82 enters the stream is determined
by the position of the stop 108; and therefore~ the spoon
~2 will move the same distance into the stream regardless
of the slze of the ou~let 48' Or the insert 34' being used.
Further7 it will be appreci~cted that any size or configura-
10 tion of insert member 34', such as those described abovein connection with FIGS. 2 through 6, can be provided with
an extending portion 106 in order to achieve the automatic
regulation of the reverse deflector spoon 82 as described
above.
When the nozzle 20~ is adapted for use with con-
ventional ring orifice devices, it can further be adapted
to automatically regulate the operative p osition of the
reverse deflector spoon 829 as can best be seen in ex-
emplary FIG. 10. In this instance, the nozzle 20 ' is ..
20 assembled in the same manner as described above in connec-
tion with exemplar~ FIG. 7, having an insert ~ember 62 and
orlfice ring 64' retained within the housing 36' by the
collar 38'. However, the orifice ring 64' is provided with
an axially extending tubular extension 120 arranged to pro-
25 ~ect outwardly from the nozzle 20'. For this purpose, thetubular extension 120~ which is preferably formed of
stainless steel~ includes a radially projecting flange
122 which is secured to the orifice ring 64' by any suitable
means9 such as by spot welding. In this way~ the tubular
30 extension 120 can be arranged for cooperating with the ad-
justable stop 108 thexeby automatically controlling the
reverse rotational speed of the sprinkler 10 ' for any size
of orifice ring 64' selected.
It should be noted that each of the insert members
35 349 34' and 62 effectively isolates the housing 36 from the
flow of water through the nozzle 20. In t;his way, the wear
life o f the housing 36 is significantly increased, and the
abrasive effect of the water flowing through the nozzle 20
acts only upon the insert members 34$ 34' and 62 which are
preferably formed of a moldableg abrasion resistant poly-
urethane material. Furtherg the threaded connection between
the range tube 18 and the housing 36 is not sub~ect to
galling due to exposure to sand or silt contamlnants be-
cause it is not necessary to remove the housing 36 from therange tube 1~ in order to change the lnsert member 34. If
the threaded connection between the housing 36 and the col_
lar 3~ should ever become galled or unworkable due to
exposure to sand or silt contaminants, it is substantially
less ex~pensive to replace the housing 36 and collar 38
than the range tube 18 which is typically welded to the
elbow 16.
From the foregoing, it will be appreciated that
the nozzle 20 of the present invention provides a device
by which the size and shape of the outlet of an lrrigation
sprinkler may be selectively varied to achieve any desired
combination of flow rate and distribution or range of throw
from the sprinkler. Furtherg the nozzle 20 may be fabri-
cated conveniently and economicallyg includes a housing
having an extended wear life~ and can be adapted to auto-
matically control tl~e reverse rotational speed of a part-
circle reaction drive sprinkler.
While several particular forms of the invention
have been illustrated and described, it will also be appar-
ent that various modifications can be made without depart-
ing from the spirit and scope of the invention.
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