U.S. patent number 3,743,187 [Application Number 05/266,393] was granted by the patent office on 1973-07-03 for nozzle.
This patent grant is currently assigned to Spirolet Corporation. Invention is credited to Maurice C. Breunsbach.
United States Patent |
3,743,187 |
Breunsbach |
July 3, 1973 |
NOZZLE
Abstract
An elongated hollow body formed of an elastomeric material
having a bore therethrough. A thread formation of helical
configuration is formed in the bore which gradually tapers towards
its outlet end. The thread formation comprises a spiral projection
and groove separated by a sloping shoulder extending forwardly from
the projection of the groove.
Inventors: |
Breunsbach; Maurice C.
(Hamburg, NY) |
Assignee: |
Spirolet Corporation (North
Tonawanda, NY)
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Family
ID: |
27358436 |
Appl.
No.: |
05/266,393 |
Filed: |
June 26, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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77880 |
Oct 5, 1970 |
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7747 |
Feb 2, 1970 |
3692243 |
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Current U.S.
Class: |
239/489;
239/DIG.19; 366/10 |
Current CPC
Class: |
E04F
21/12 (20130101); B05C 11/00 (20130101); Y10S
239/19 (20130101) |
Current International
Class: |
E04F
21/02 (20060101); B05C 11/00 (20060101); E04F
21/12 (20060101); B05b 001/34 () |
Field of
Search: |
;239/399,403,405,489,487,602 ;259/151 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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224,075 |
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Nov 1924 |
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GB |
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518,776 |
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Mar 1940 |
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GB |
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Primary Examiner: Wood, Jr.; M. Henson
Assistant Examiner: Love; John J.
Parent Case Text
CROSS-REFERENCE TO A RELATED APPLICATION
This application is a continuation of application Ser. No. 77,880,
filed Oct. 5, 1970 entitled Nozzle now abandoned, which application
is a continuation-in-part of my earlier application Ser. No. 7747
filed Feb. 2, 1970 on a Nozzle now U.S. Pat. No. 3,692,243.
Claims
I claim:
1. A nozzle for directing cementitious material therethrough
comprising: an elongated body of elastomeric material having a bore
therethrough, an inlet end and an outlet end, said bore having a
mixing chamber intermediate the opposite ends thereof, said mixing
chamber being provided with a helical threaded formation on the
wall surface defining said mixing chamber, said threaded formation
comprising a spiral projection, a spiral groove, and means on the
side of said projection toward said outlet end for providing a
gradual transistion from said projection to said groove for
controlling turbulence within said mixing chamber.
2. A nozzle as set forth in claim 1 wherein said elastomeric
material is urethane.
3. A nozzle as set forth in claim 1 wherein said body is of a
unitary, one-piece construction.
4. A nozzle as set forth in claim 1 wherein said bore gradually
tapers toward said outlet end.
5. A nozzle as set forth in claim 1 wherein said means for
controlling turbulence comprises a spiral formation providing a
convexly curved transition surface.
6. A nozzle as set forth in claim 1, wherein said mixing chamber is
provided with a double helical thread formation each of which
comprises a spiral projection, a spiral groove and means on the
outlet side of said projection for providing a gradual transition
surface from said projection to said groove thereof.
7. A nozzle as set forth in claim 1 wherein said mixing chamber is
elongated and said projection has an inner peripheral land surface
of substantial axial extent.
8. A nozzle as set forth in claim 1, wherein said mixing chamber is
elongated and said threaded formation extends continuously
therealong.
9. A nozzle as set forth in claim 8, said nozzle bore having an
outlet chamber leading from said mixing chamber to said outlet end,
said mixing and outlet chambers tapering toward said outlet end and
said outlet chamber having a smooth inner wall surface.
10. A nozzle for directing cementitious material therethrough
comprising: an elongated body of elastomeric material having a bore
therethrough, an inlet end and an outlet end, said bore having a
mixing chamber intermediate the opposite ends thereof, said mixing
chamber being provided with a helical threaded formation on the
wall surface defining said mixing chamber, said threaded formation
comprising a spiral projection, a spiral groove, and means for
controlling turbulence within said mixing chamber, wherein said
means controlling turbulence comprises a spiral formation disposed
between said projection and said groove on the side of said
projection toward said outlet end and having a sloping surface
extending from said projection to said groove.
11. A nozzle as set forth in claim 10 wherein said mixing chamber
is elongated and said threaded formation extends continuously
therealong, said mixing chamber being provided with a double helix
thread formation each of which comprises a spiral projection and a
spiral groove and a spiral formation disposed therebetween on the
outlet side of said projection, each of said spiral formations
having a sloping surface extending from the associated projection
to the associated groove and providing a gradual transition
therebetween to controlling turbulence within said mixing
chamber.
12. A nozzle as set forth in claim 10, wherein said spiral
formation is convexly curved, having its rearward edge slightly
outwardly offset from the forward edge of said projection.
13. A nozzle as set forth in claim 12, said offset providing a
spacing shoulder which is inclined forwardly and outwardly at a
sharp angle.
14. A nozzle for directing cementitious material therethrough
comprising: an elongated body of elastomeric material having a bore
therethrough, an inlet end and an outlet end, said bore having a
mixing chamber intermediate the opposite ends thereof, said mixing
chamber being provided with a helical threaded formation on the
wall surface defining said mixing chamber, said threaded formation
comprising a spiral projection, a spiral groove, and means for
controlling turbulence within said mixing chamber, wherein said
projection is provided with a leading face on the side thereof
toward said inlet end, said leading face being provided with an
undercut at the juncture of said face with the inner wall of said
bore.
15. A nozzle as set forth in claim 14, wherein said groove extends
to said face and said undercut is at the juncture thereof.
Description
BACKGROUND OF THE INVENTION
This invention relates to nozzles and, more particularly, to
nozzles for mixing and handling cementitious materials.
Various discharge nozzles have been designed in recent year for
applying wet cementitious materials to a background surface.
Generally, a cementitious material in dry particle form is
pneumatically blown into these nozzles wherein it is mixed with
water to form a wet cementitious admixture projected through the
nozzle outlet to the desired location. One specific use for such
cement gun nozzles is in applying a lining of refractory
cementitious material to the walls of a high temperature furnace.
One problem encountered in the use of these nozzles for applying
air-emplaced material is that improper blending of the water with
the dry material forms an admixture of undesirable plasticity which
fails to adhere properly to the background surface. It has been
found that insufficient mixing of the water with the dry materials
results in excessive "rebound" whereas excessive wetting of the dry
materials causes the mixture to run at the background surface and
form a weak, finished structure. Rebound results in wastage of
materials and necessitates periodic clean-up of such rebound
requiring added labor and equipment shut down, thereby materially
increasing costs.
In some nozzle designs, excessive turbulence is generated whereby
the finer particles of the granular mix tend to separate from the
larger particles resulting in a mix of non-uniform consistency.
Also, these fines tend to alternate into elongated filaments and
are whipped into a froth-like substance by this excessive
turbulence which is collected in a mass at the discharge end of the
nozzle, ultimately dropping to the floor or other operator
supporting surface rendering the latter sloppy and creating a
potential safety hazard.
The invention claimed and disclosed in U.S. Pat. application Ser.
No. 7747, filed Feb. 2, 1970, overcomes many of the prior art
deficiencies by employing a nozzle having a thread formation of
helical configuration formed in the bore of the nozzle to impart a
spiral twist or rifling motion to the cementitious ingredients
thereby insuring a thorough mix thereof and producing a highly
controlled delivery with very little rebound and dust. The present
invention constitutes an improvement over U.S. application Ser. No.
7747 by making certain improvements in the bore of the nozzle and
in the helical thread formation to produce a more highly efficient
nozzle.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an
improved nozzle which is even more effective in overcoming the
above-noted disadvantages.
It is another object of this invention to provide the foregoing
nozzle with an improved internal thread configuration for
facilitating the blending of the dry cementitious ingredients with
the water while controlling the degree of turbulence generated in
the nozzle.
In one aspect thereof, the cement gun nozzle of this invention is
characterized by the provision of a nozzle bore having a unique
thread configuration of a generally double helical pattern formed
in the inner wall surface of the bore. Each of the helices consist
of a thread projection and a groove separated by a curved shoulder
extending from the projection in a sloping radial outward direction
and terminating at the groove to control turbulence imparted to the
material conveyed through the nozzle bore.
These and other objects, advantages and characterizing features of
the present invention will become clearly apparent from the ensuing
detailed description of an illustrative embodiment thereof, taken
together with the accompanying drawing wherein like reference
characters denote like parts throughout the various views.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
FIG. 1 is a side elevational view of a nozzle of the present
invention, shown attached to a liquid injection adaptor:
FIG. 2 is a longitudinal sectional view of the nozzle of FIG.
1;
FIG. 3 is a cross sectional view, on an enlarged scale, taken about
on line 3--3 of FIG. 2; and
FIG. 4 is a fragmentary, sectional view, on an enlarged scale,
taken about on line 4--4 of FIG. 2.
DETAILED DESCRIPTION OF AN ILLUSTRATED EMBODIMENT
Referring now in detail to the drawings, there is shown in FIG. 1 a
nozzle, generally designated 10 and constructed in accordance with
this invention, attached to a liquid injection adaptor, generally
designated 12. Adaptor 12 comprises a body 15 adapted to be
threaded at one end thereof on the inlet end of nozzle 10 and
having a bore (not shown) therethrough provided with threads at the
other end of adaptor 12 for receiving a suitable hose coupling (not
shown) through which dry cementitious material from a suitable
source (not shown) is conveyed by air under pressure to adaptor 12
and nozzle 10. A radially extending tapped opening is provided in a
boss 13 of adaptor 12 for receiving a suitable conduit connection
through which water or some other suitable liquid is introduced
into the interior of adaptor 12 and nozzle 10 for admixing with the
dry cementitious ingredients. Such general arrangement, being known
in the art, requires no further description here.
Nozzle 10 comprises an elongated hollow body 14 (FIG. 2) having a
generally cylindrical outline but slightly tapered toward the
discharge end. Body 14 is provided with an inlet end 16 and an
outlet end 18, the inlet end 16 being externally threaded as at 20
for threaded engagement with adaptor 12 or some other suitable
connection means. An annular projection or rib 22 is formed on the
outer annular face of nozzle 10 at the inlet end thereof to provide
a fluid tight seal seating against the abutting end of adaptor 12.
Two pairs of diametrically opposed lugs 24 and 26 are formed on the
outer surface of nozzle 10, integral therewith, for facilitating
the grasping and handling of nozzle 10.
Nozzle 10 is composed of an elastomeric material, preferably
urethane, which is wear and abrasion resistant and sufficiently
rigid to accurately guide a stream of material in the desired
direction. Nozzle 10 is of a unitary, one-piece construction formed
by a suitable molding operation and can be of any convenient size
for a given application.
Nozzle 10 is provided with an axial bore, generally designated 28,
having a first chamber 30 at the inlet end 16 and defined by a
cylindrical wall surface 32, an elongated, intermediate mixing
chamber 34, and an outlet chamber 36 defined by a smooth inner wall
surface 38 which tapers toward outlet end 18. The intermediate and
outlet chambers 34 and 36, respectively, taper from the inner end
of chamber 30 to the outer end of outlet chamber 36. This gradual
taper tends to choke the cementitious mix as it is conveyed
outwardly through nozzle 10 to minimize spreading of such mix and
to constrain the projecting stream within the desired path.
A significant feature of this invention is the provision of a
specially configurated double helical thread formation, generally
designated 40, defining the inner wall surface of mixing chamber
34. Since both helices are identical, it is believed that a
detailed description of only one will suffice, it being understood
that the helices bear identical reference characters and are spaced
180.degree. apart. As shown in FIGS. 2, 3 and 4, each helix
formation comprises a projection 42 and a groove 44 separated by a
curved, sloping shoulder 46. The significance of sloping shoulder
46 to provide a gradual, curving transition between projection 42
and groove 44 will appear from the following.
It has been found that the spiral, twisting motion imparted to the
admixture of the dry cementitious material, water and air by thread
formation 40 effects a cyclonic-like turbulence of these
ingredients to efficiently mix the same, resulting in a consistent
and thorough mix. The incoming material impinges against the
abutment surface defined by the leading face 48 of projection 42
and is guided in groove 44 in a spiraling or rifling motion. While
the material is guided in a generally spiral path of movement, it
also has an axial component whereby some of the material tends to
flow generally axially along the outer surface of projection 42. If
groove 44 were to extend completely across the space between
adjacent projections 42, a vacuum would be created in the space
just rearwardly of the trailing face of projection 42. The suction
force of the vacuum, together with the action of centrifugal force
would direct the material radially outwardly against the groove
tending to create excessive turbulence or agitation causing the
fines to be separated from the larger particles to produce a
finished cementitious mix of non-uniform consistency. Also, as a
result of this excessive turbulence, these fines would be
attenuated into elongated filaments and churned or whipped into a
frothlike substance. While this frothlike substance constitutes
only a negligible portion of the finished mix, it tends to collect
at the outlet end of the nozzle and drop off onto the floor or
other support surface in close proximity to the operator's feet.
This not only pollutes the adjacent working area, but also presents
a potential safety hazard to the operator and other personnel in
the area.
The provision of shoulder 46 in the nozzle of this invention
occupies and eliminates the space forwardly of projection 42 which
would otherwise be present in the absence of such shoulder and
provides a smooth, curving surface forwardly of projection 42 which
merges into groove 44 and upon which the incoming material slides
so as to be gradually directed into groove 44, thereby reducing the
turbulence to within tolerable limits and eliminating the problems
encountered with extreme turbulence. Thus, shoulder 46 is an
important feature of this invention in controlling the axial and
spiraling flow characteristics imparted to the cementitious
mixture.
It has been found that the best results are achieved when the rear
edge of shoulder 46 is slightly outwardly offset from the front
edge of projection 42. The offset should be very minor, so as not
to interfere with the intended function of shoulder 46. The offset
provides a spacing shoulder 45 which is inclined forwardly and
outwardly at a sharp angle.
A sand hook or undercut 50 is formed at the juncture of groove 44
and leading face 48 of projection 42 for the purpose of trapping a
small portion of the granular material therein. This trapped
material forms a coating or wear surface protecting at least a
portion of the leading face 48 against the abrasive action of the
cementitious mix and thereby extending the useful life of the
nozzle. It has been found that a 5 degree undercut is satisfactory
in providing an adequate cavity for trapping material therein.
However, larger or smaller undercuts can be employed as dictated by
the size of the nozzle, the force of the air pressure applied, and
the type of material forced through the nozzle.
From the foregoing, it is apparent that the objects of the present
invention have been fully accomplished. As a result of this
invention, an improved gun nozzle is provided for thoroughly mixing
dry cementitious materials with water to form a mix of optimum
density and consistency. By the provision of a thread formation
formed in the inner wall of the nozzle, a spiral twisting or
rifling motion is imparted to the admixture as it is forced under
pressure through the nozzle, and the thread formation is provided
with a shouldered portion providing a gradual sloping transition
from the thread projection to the groove to effectively control the
turbulence within the nozzle. Also, the nozzle bore is tapered
axially to the outlet end thereof for effecting a choking action of
the mixture issuing from the nozzle to produce an efficiently
controlled delivery with very little rebound.
A preferred embodiment of this invention having been described in
detail, it is to be understood that this has been done by way of
illustration only.
* * * * *