Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
Nozzles through which fluids are supplied may
become blocked from time-to-time with foreign materials
in the fluid. For example, pulpwood grinding equipment
commonly employs stone showers provided with what are
usually referred to as nozzles. From time-to-time
foreign matter will block the nozzles, creating the need
for cleaning of the same, since plugged nozzles can result
in serious damage to the equipment intended to be showered
by the nozzles.
Self-cleaning nozzles are known. For example,
reference may be made to the following U.S. Patents:
2,186,214, H.F. Simon, January 9, 1940; 1,789,625, A.M.
Goodloe, January 20, 1931; 2,614,885, W.J. Roell et al,
15 October 25, 1952; 4,248,381, John B. Vessels~ February
3, 1981; and 2,311,018, A.H. Bahnson, Jr., February 16,
1943. The nozzles or other devices shown in these patents
are subject to one or more of the following disadvantages-
mechanical complexity, employment of diaphragms and springs
that can weaken and fail and use of a large number of
parts.
In accordance with an aspect o~ this invention,
there are provided nozzles which avoid the aforementioned
disadvantages.
Summary of the Invention
According to one aspect of the present invention ;
there is provided a self-cleaning~nozz1e comprising a cylinder
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having first and second ends, a side wall and a hollow
interior, said cylinder having first, second and third
openings therein extending into said interior thereof,
said second opening being located intermediate said first
and third openings, said first opening when open communi-
cating in fluid-flow relationship with said interior
of said cylinder, a piston slidably mounted in said
interior of said cylinder, said piston including a
cleaning tip that is movable into said irst opening
to clean said first opening when said piston is moved
from a first position in said cylinder to a second
position in which said cleaning tip is inserted into
said first opening, a first source of fluid under pressure,
a second source of fluid, means for varying the pressure
of the fluid of said second source between a first
pressure and a second pressure, said first source of
fluid communicating in fluid-flow relationship with said
interior of said cylind~r via said second opening ahd
exerting a force tending to move said piston in a first
direction, said second source of fluid communicating
in fluid-flow relationship with said interior of said
cylinder via said third opening and exerting ~ force
tending to move said piston in a second direction opposite
to said first direction, said piston being constructed
and arranged such that when said pressure of said second
source is at said first pressure the force exerted by
the pressure of said second source on said piston is
greater than the force exerted by the pressure of said
first source on said piston and said p1ston moves to
said second position thereof and when said pressure of
said second source is at said second pressure the force
exerted by the pressure of said second source~on said
piston is less than the force exerted by the pressure
of said first source on said piston and said piston moves
to said first posltion thereof where said cleaning tip
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is withdrawn from said first opening, the pressure of
said first source of fluid and the pressure of said
second source of fluid acting on said piston being the
sole means for moving said piston in said first and
second directions, in said first position of
said piston said first source of fluid
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communicating in ~luid-flow relationship with said
interior of said cylinder and there~y with said first
opening, whereby fluid from said first source is ejected
through said first opening, in both positions of said
piston said piston blocking flow of fluid between said
first and second sources.
Brief Description of the Drawings
This invention will become more apparent from
the following detailed description, taken in conjunction
with the appended drawings, in which:
Figure l is a section through pulpwood grinding
equipment employing nozzles embodying the instant invention,
portions of the equipment being shown schematically and
only a part of the pulpwood grinding stone being illustrated;
and
Figures 2 and 3 are longitudinal sections through
a self-cleaning nozzle embodying the instant invention
showing the nozzle in the operating mode ~Figure 2) and
in the cleaning mode (Figure 3).
_ tailed Description of the Invention
Including the_Preferred Embod ent
Referring first to Figure 1, the pulpwood grinding
equipment shown therein includes a conventional grinding
stone lO and shower apparatus generally designated 11.
The shower apparatus includes nozzles 12 embodying the
instant invention and two ducts or headers 13 and 14.
Header 14 is connected at one end via a flow
control valve 15 to a shower water supply, while the
other end thereof is connected via a purge val~e 16 to
a sewer.
Header 13, on the other hand, is connected via
a nGzzle control valve 17 to either a regulated high
pressure supply of any suitable fluid,~e.g., water or
to a sewer.
In the arrangement shown in Figure 1 four nozzles
are provided and are located and arranged in the positions
indicated in the Figure. This is not critical to the
~' instant invention, and different numbers of nozzles may
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be employed, and they may be arranged and configured
in different ways.
As best shown in Figures 2 and 3, openings 18
are provided in the walls that define headers 13 and
14, and nozzles 12 are accommodated in these openings
being secured to the walls defining the headers in any
convenient way, e.g., by welding.
Each self-cleaning nozzle includes a cylinder
19 that has ends 20 and 21, a side wall 22 which, in
the embodiment illustrated, is of annular configuration,
and a hollow interior 23.
Cylinder 19 has three openings 24, 25 and 26
extending into interior 23 thereof, opening 25 being
located intermediate openings 24 and 26. Opening 26
actually is provided in a cylindrical member 27 that
is threaded into engagement with side wall 22 at end
21 thereof, but this is not essential to the instant
invention, and opening 26 may be provided in an end wall
of cylinder 19 formed integral with side wall 22.
A piston 28 is slidably mounted in the interior
23 of cyl1nder 19. In the embodiment of the invention
illustrated, piston 28 is cylindrical in configuration,
the cross-sectional shape of piston 28 being dictated
by the cross-sectional shape of the interior 23 of cylinder
19. Piston 28 includes a cleaning tip 29 that is movable
into opening 26 to clean that opening when piston 28
is moved from the position shown in Figure 2, which is
the operating mode of the nozzle, to the position shown
in Figure 3, which is the cleaning position of the noæzle.
It will be appreciated that the effect of cleaning tip
29 moving into opening 26 is to force out through the
opening any foreign particle that may have become lodged
in opening 26.
It will be noted that piston 28 is provided
with a chamfer at 31 and with a stepped surface 32. Also
the interior of piston ~28 is hollow, being provided
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with a cylindrical bore 3~
The upper end of cylinder l9 has a cap 34 thread-
ably engaged therewith and provided with a pin or project-
ion 35 that is slightly smaller in diameter than the
diameter of hore 33, pin 35 fitting into bore 33 in the
position of piston 28 shown in Figure 2 with some clearance
provided between pin 35 and the walls of bore 33.
Shower water at a pressure of, say~ 150 p.s.i.
is supplied to header 14 via flow control valve 15 (Fig.
l), from the shower water supply. Purge valve 16 is
closed, of course.
In the operating mode piston 28 is in the posi-
tion shown in Figure 2, so that the shower water enters
cylinder l9 via opening 25 and passes from the interior
23 of cylinder 19 through opening 26 to be ejected onto
stone 10 (Figure 1)~. :
When~it~is desired to clean nozzle 12, fluid
under pressure is introduced into header 13 by moving
nozzle control valve 17 (Figure 1) so that it is connected
to a source of regulated high pressure fluid, say, water
at 200 p.s.i. This high pressure fluid acting first
on step 32 and then subsequently on the whole upper end
surface of piston 28 and the surface defining bore 33
exerts a force which is sufficient.to overcome the force
which is exerted by the pressure of the shower water
acting on chamfered surface 31, the annular surface 38
immediately adjacent thereto and between chamfered surface
31 and pin 29 and the end surface of:pin 29, with the
result that piston 28 is forced to move from the position
thereof shown in Figure 2 to the position thereof shown
in Figure 3. As previously explained, when this occurs, : :
tip 29 moves through opening 26 cleaning any foreign .
material therefrom. : ~
The procedure is reversed by moving nozzle control
valve 17 (Figure 1) to a position wherein header 14 is
disconnected from the regulated high pressure supply
and is connected to a sewer at atmospheric pressure,
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i.e., the same pressure as that to which opening 25 exits.
Under these circumstances, the pressure of the shower
water acting on chamfered surface 31 and then on ann-
ular surface 38-adjacent thereto and finally on the end
of cleaning tip 29 produces a force which moves piston
28 from the position thereof shown in Figure 3 to the
position thereof shown in Figure 2. Any mechanical shock
which might be created as a result of this movement is
cushioned by pin 35 being injected into bore 33 causing
the displacement of water from bore 33 and thus preventing
any sudden impact between piston 28 and cap 34.
As may be seen from Figures 2 and 3, in either
position of piston 28 it prevents the flow of fluid between
headers 13 and 14.
While, in the embodiment of the invention herein-
before described,the fluid supplied to header 13 was
indicated as being at a higher pressure than the pressure
of the shower water supplied to header ~4, this is not
absolutely essential to the invention. It is well known
that F = P x A, where F stands for force, P stands fox
pressure,and A stands for the area on which the pressure
acts. What is necessary, when the nozæle is going from
the operating mode to the cleaning mode, is that the
- force acting downwardly on the piston exceed the force
acting upwardly on the piston, the opposite being true
when the nozzle is to be changed from the cleaning mode
to the operating mode. These objectives can be achieved
by varying the areas acted upon by the fluids in headers
13 and 14 and/or by varying the pressures of these
fluids.
While a preferred embodiment of the invention
has been described herein, those skilled in the art will
appreciate that changes and modifications may be made
therein without departing from the spirit and scope of
the invention as de~ined in the appended claims.
