Note: Descriptions are shown in the official language in which they were submitted.
WO 2023/077492
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FLUID PUMP
TECHNICAL FIELD
[0001] Embodiments of the technology relate, in general, to
systems, apparatuses and
methods for pumping fluids, particularly liquids.
BACKGROUND
[0002] Liquid pumps find usefulness in many applications. For
example, liquid pumps can
be utilized to disperse insecticides, herbicides, fertilizers, and the like
from a liquid container. For
many applications, a relatively small, relatively quiet, and/or relatively low
cost pump can be
beneficial.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] Various embodiments will become better understood with
regard to the following
description, appended claims and accompanying drawings wherein:
[0004] FIG. 1 is an isometric view of a pump assembly for
pumping fluid;
[0005] FIG. 2 is an exploded view of the pump assembly of FIG.
1;
[0006] FIG. 3 is a partially transparent isometric view of the
pump assembly of FIG. 1 with
the inlet connector removed;
[0007] FIG. 4 is a partially transparent rotated isometric view
of the pump assembly of
FIG. 1;
[0008] FIG. 5 is a partially transparent rotated isometric view
of the pump assembly of
FIG. 1 with the motor removed;
[0009] FIG. 6 is a front elevation view of the pump assembly of
FIG. 1;
[0010] FIG. 7 is an isolated back isometric view of an upper
cover of the pump assembly
of FIG. 1 depicting an inlet chamber and an outlet chamber, in accordance with
one embodiment;
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[0011] FIG. 8 is an isolated back isometric view of a cylinder
housing of the pump
assembly of FIG. 1, in accordance with one embodiment;
[0012] FIG. 9A is a cross sectional view of a portion of the
pump assembly taken along
the line 9A-9A of FIG. 6;
[0013] FIG. 9B is a cross sectional view of a portion the pump
assembly taken along the
line 9B-9B of FIG. 6;
[0014] FIG. 9C is a cross sectional view of a portion of the
pump assembly taken along
the line 9C-9C of FIG. 6;
[0015] FIG. 10 is a side view depicting an interior portion of
an exemplary hand-held fluid
dispenser including the pump assembly of FIG. I; and
[0016] FIG. 11 is a schematic representation of a system and
method for pumping fluid.
DETAILED DESCRIPTION
[0017] Certain embodiments are hereinafter described in detail
in connection with the
views and examples of FIGS. 1-11, wherein like numbers indicate the same or
corresponding
elements throughout the views.
[0018] Various non-limiting embodiments of the present
disclosure will now be described
to provide an overall understanding of the principles of the structure,
function, and use of the
apparatuses, systems, methods, and processes disclosed herein. One or more
examples of these
non-limiting embodiments are illustrated in the accompanying drawings. Those
of ordinary skill
in the art will understand that systems and methods specifically described
herein and illustrated in
the accompanying drawings are non-limiting embodiments. The features
illustrated or described
in connection with one non-limiting embodiment may be combined with the
features of other non-
limiting embodiments. Such modifications and variations are intended to be
included within the
scope of the present disclosure.
[0019] Reference throughout the specification to "various
embodiments," "some
embodiments," "one embodiment," "some example embodiments," "one example
embodiment,"
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or "an embodiment" means that a particular feature, structure, or
characteristic described in
connection with any embodiment is included in at least one embodiment. Thus,
appearances of the
phrases -in various embodiments," -in some embodiments," "in one embodiment," -
some
example embodiments," "one example embodiment," or "in an embodiment" in
places throughout
the specification are not necessarily all referring to the same embodiment.
Furthermore, the
particular features, structures or characteristics may be combined in any
suitable manner in one or
more embodiments.
[0020] The examples discussed herein are examples only and are
provided to assist in the
explanation of the apparatuses, devices, systems, and methods described
herein. None of the
features or components shown in the drawings or discussed below should be
taken as mandatory
for any specific implementation of any of these the apparatuses, devices,
systems, or methods
unless specifically designated as mandatory_ For ease of reading and clarity,
certain components,
modules, or methods may be described solely in connection with a specific
figure. Any failure to
specifically describe a combination or sub-combination of components should
not be understood
as an indication that any combination or sub-combination is not possible.
Also, for any methods
described, it should be understood that unless otherwise specified or required
by context, any
explicit or implicit ordering of steps performed in the execution of a method
does not imply that
those steps must be performed in the order presented but instead may be
performed in a different
order or in parallel.
[0021] Technical solutions to issues related to size, noise, and/or
cost of fluid pumps can be
achieved by the systems, apparatuses, assemblies, and methods of the present
disclosure. In general,
the disclosed assemblies and apparatuses can be used to spread, inject, or
otherwise distribute
fluids supplied to the assembly and apparatus according to the systems and
methods of the
disclosure. In general, the components of the apparatuses and assemblies
described herein, unless
otherwise described, can be made of plastic materials, including injection-
molded plastic materials.
The materials of disclosed pumps and pump components can be selected for
chemical resistance,
wear resistance, and/or durability, depending on the fluid pump's use
application.
[0022] FIGS. 1-9C illustrate a pump assembly 100 according to an
example embodiment of
the present disclosure. The pump assembly 100 can include an upper cover 111,
a cylinder housing
123, a gearbox 106, and a motor 102. The upper cover 111 can be sealingly
coupled to a first end
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(e.g., a front end) of the cylinder housing 123 using any number of sealing
mechanisms or
processes (e.g., glue, fasteners, gaskets, plastic welding, wax, tape, etc.),
either individually or in
combination. The gearbox 106 can include a gearbox housing 107, which can be
coupled or
otherwise attached to a second end (e.g., a back end) of the cylinder housing
123 to provide for a
moisture- and contaminant-resistant enclosure. As shown in FIGS. 1-2, the gear
box housing 107
can include a plurality of attachment tabs 125, each being sized and shaped to
cooperate with a
corresponding latching connector 124 of the cylinder housing 123. In such
arrangements, the
gearbox housing 107 can be detachably coupled to the cylinder housing 123. It
should be
appreciated, however, that in other embodiments, the gearbox housing 107 can
be fixedly secured
to the cylinder housing 123.
[0023] Referring now to FIGS. 1-4, the pump assembly 100 can be
powered by a motor, such
as, for example, the motor 102. During operation, the motor 102 is configured
to rotate a motor
output shaft 108 at a reference rotational speed. The motor 102 can be an
electric motor energized
by a portable power source such as, for example, one or more batteries. As
shown in FIG. 4, the
motor 102 includes electrical connectors 104, which can be electrically
coupled to the portable
power source for powering or energizing the motor 102. The motor 102 can be
operatively coupled
to the pump assembly 100 by the gearbox 106. As shown in FIGS. 3-5, the
gearbox 106 can include
a plurality of intermeshing gears 109. As described in more detail below, the
gears 109 are
configured to change, including reduce, a first rotational speed of the motor
output shaft 108 of
the motor 102 to a second rotational speed of an actuator 130 rotating about a
plate 113 of the
pump assembly 100.
[0024] The plate 113 can be a disk-shaped washer sized and shaped
to receive respective gear
shafts 115 of the plurality of intermeshing gears 109 of the gearbox 106 on
one side and provide a
surface about which the actuator 130 can rotate about on the other side. For
example, in some
embodiments, such as the one shown in FIG. 2, the plate 113 can include a
substantially round and
flat front surface about which the actuator 130 can rotate. On its rear
surface, the plate 113 can
include a plurality of cylindrically-shaped bushings extending therefrom,
which are configured to
receive the gear shafts 115 and aid in maintaining proper positioning of the
various gears 109 of
the gearbox 106. The plate 113 can be coaxially aligned with a threaded
securement 110, which as
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disclosed in more detail below, can join separate components of the actuator
130, in some
embodiments.
[0025]
As described above, the pump assembly 100 includes an actuator 130.
Referring to FIG.
2, the actuator 130 can include a first actuator member 132 and a second
actuator member 134.
The first actuator member 132 and the second actuator member 134 are generally
cylindrical and
when joined form the actuator 130 having an annular groove that is a cam path
136 (FIGS. 3-4).
As depicted in FIG. 9A, a first portion including a first cam surface 136A of
the annular groove is
molded into, or machined into, the first actuator member 132 and a
complementary second portion
including a second cam surface 136B of the annular groove is molded into, or
machined into, the
second actuator member 134. In some embodiments, such as the one shown in
FIGS. 2-4, the first
actuator member 132 and the second actuator member 134 are joined together
with a threaded
securement 110. When the first actuator member 132 is joined to the second
actuator member 134,
such as by the threaded securement 110, the first cam surface 136A is in a
generally parallel,
spaced-apart relationship to the second cam surface 136B and define the cam
path 136. It should
be appreciated that any other attachment or securement mechanisms can be used
to join the first
actuator member 132 and the second actuator member 134 together.
Alternatively, in some
embodiments, the actuator 130 can be a single integral or monolithic component
having the first
cam surface 136A and the second cam surface 136B forming the cam path 136.
[0026]
As shown in FIGS. 4-5, the bottom portion of the actuator 130, below the
cam path 136,
is cylindrically-shaped. A plurality of teeth 135 are formed or otherwise
extend from the inner
surface of the cylindrically-shaped bottom portion of the actuator 130. The
teeth 135 are sized and
shaped to cooperate with one or more teeth of the intermeshing gear 109 such
as, for example, the
teeth of gear 109c. In operation, rotation of the motor output shaft 108 by
the motor 102 causes
the intermeshing gears 109a-c to rotate, which then causes the actuator 130 to
rotate about the plate
113.
[0027]
Referring again to FIGS. 1 and 3, the pump assembly 100 can include an
inlet port
152 and an outlet port 156. In an embodiment, the inlet port 152 and/or an
outlet port 156 can be
joined to, or molded into, the upper cover 111, which can be joined to the
cylinder housing 123.
The pump assembly 100 may, in an embodiment, include an inlet connector 153
(shown best in
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FIGS. 4 and 9). The inlet connector 153 may be coupled to the cover 111 and
include an inlet port
157 fluidically coupled with the inlet port 152.
[0028] The cylinders, actuator, and other working components of the
pump assembly 100, as
described below, can be housed in a cylinder housing 123. The pump assembly
100 can include a
plurality of pistons. In an embodiment, the pump assembly 100 includes a first
piston 112 and a
second piston 114. The first piston 112 and the second piston 114 each
reciprocate in a linearly
parallel configuration inside a first cylinder 116 and a second cylinder 118,
respectively. The first
cylinder 116 and the second cylinder 118 can each be a cylindrical-shaped bore
inside the cylinder
housing 123, shown in more detail in FIGS. 8 and 9A. The cylinder housing 123
can be joined to
the gearbox housing 107 and can cooperate to house the gearbox 106 and the
actuator 130
(described more fully below). The first piston 112 is generally cylindrical,
having a central axis
142 being coaxial with a central axis 144 of the first cylinder 116. Likewise,
the second piston 114
is generally cylindrical, having a central axis 146 being coaxial with a
central axis 148 of the
second cylinder 118. In an embodiment, the first piston central axis 142, the
second piston central
axis 146 are parallel. In an embodiment, the first piston central axis 142,
the second piston central
axis 146, and the central axis 150 of the actuator 130 are each parallel and
coplanar. A first piston
seal 120 can be sized to provide for a substantially leak-free seal between an
outer surface of the
first piston 112 and the inner wall of the first cylinder 116. Likewise, a
second piston seal 122 can
be sized to provide for a substantially leak-free seal between an outer
surface of the second piston
114 and the inner wall of the second cylinder 118. In an embodiment, the first
piston seal 120 and
the second piston seal 122 can be an 0-ring disposed at or near a distal end
of the first cylinder
116 and the second cylinder 118, respectively. Thus, each cylinder 116, 118 is
a variable-volume
fluid reservoir, with the volume being cyclically alternating from a first
minimum volume to a
second maximum volume as a function of the reciprocating motion of the
corresponding piston.
[0029] As shown in FIG. 2, in an embodiment, a piston holder 119
can facilitate retention of
the first and second pistons 112, 114 within the cylinder housing 123 (i.e.,
within the first and
second piston cylinders 116, 118, respectively). The piston holder 119 can
define a slot 151 (one
shown) on each of opposing sides in which a connecting rod pin (e.g., 138,
140) on each respective
piston (e.g., 112, 114) (and which can be oriented opposite the respective cam
followers 138, 140)
can travel with the reciprocating piston. The connecting rod pin (e.g., 138,
140) in the slot 151 can
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prevent the pistons 112 114 from rotating and becoming disconnected from the
rotating actuator
130 that provides the reciprocating movement of the pistons 112, 114.
[0030] Each of the first piston 112 and the second piston 114 can
be actuated in reciprocating
motion within the first and second piston cylinders 116, 118 by the rotation
of the actuator 130.
The actuator 130 rotates via an actuator shaft that is driven by the motor 102
via the gearbox 106.
The actuator 130 can comprise a first actuator member 132 and a second
actuator member 134
(FIG. 2). The first actuator member 132 and the second actuator member 134 can
be generally
cylindrical and can be coupled together to form the actuator 130. The first
actuator member 132
and the second actuator member 134 can cooperate to define a cam path 136
(FIGS. 3-4) that is
formed as an annular groove. As depicted in FIG. 9A, a first portion including
a first cam surface
136A of the cam path 136 is molded into, or machined into, the first actuator
member 132 and a
complementary second portion including a second cam surface 136B of the cam
path 136 is
molded into, or machined into, the second actuator member 134. When the first
actuator member
132 is joined to the second actuator member 134, such as by the threaded
securement 110, the first
cam surface 136A is in a generally parallel, spaced-apart relationship to the
second cam surface
136B and define the cam path 136.
[0031] The first piston 112 has at or near its proximal end a first
cam follower 138 that extends
into the cam path 136. Likewise, the second piston 114 has at or near its
proximal end a second
cam follower 140 that extends into the cam path 136. Thus, each piston 112,
114 is coupled by
their respective cam followers 138, 140 to the actuator 130 in such a way that
rotation of the
actuator 130 causes each of the first and second pistons 112, 114 to slide
(e.g., translate) either
downwardly (e.g., an intake stroke) or upwardly (e.g., an exhaust stroke). For
each of the first and
second cylinders 116, 118, fluid can be drawn into the respective cylinders
(116, 118), during the
intake stroke and exhausted from the respective cylinders (116, 118) during
the exhaust stroke.
The stroke direction of the first piston 112 can be opposite the stroke
direction of the second piston
114 such that when the first piston 112 is in its intake stroke (e.g., sliding
downwardly), the second
piston 114 can be in its exhaust stroke (e.g., sliding upwardly) and vice
versa. . Each of the first
and second pistons 112, 114 can have a top dead center position that
corresponds to a position of
maximum advance and a bottom dead center position that corresponds to a
position of maximum
retraction. The advance position of the first piston 112 can be opposite the
advance position of the
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second piston 114 such that when the first piston 112 is at top dead center,
the second piston 114
is at bottom dead center and vice versa.
[0032] As best depicted in FIGS. 7, 9A, and 9B, in one embodiment,
the first and second
cylinders 116, 118 can be in fluid communication at their respective distal
ends with an inlet
chamber 158 and an outlet chamber 159. As will be described in further detail
below, when the
first piston 112 travels through its intake stroke, fluid can be drawn from
the inlet port 152, through
the inlet chamber 158 and into the first cylinder 116. When the first piston
112 travels through its
exhaust stroke, fluid can be expelled from the first cylinder 116, through the
outlet chamber 159
and discharged from the outlet port 156. The second piston 114 can operate in
a similar manner.
[0033] Referring now to FIG. 9A, a first inlet check valve 160 can
be associated with the first
cylinder 116 and can be selectively operable in either a closed state or an
opened state. When in
the closed state, the distal perimeter portion of the circularly extending
flap of the first inlet check
valve 160 can be sealed over openings 163 (see FIG. 8) that extend to the
inlet chamber 158 to
substantially seal and prevent fluid flow from the first cylinder 116 into the
inlet chamber 158.
When in the opened state, the distal perimeter portion of the circularly
extending flexible flap of
the first inlet check valve 160 can be outwardly biased, thereby permitting
fluid flow from the inlet
chamber 158, through the openings 163 (FIG. 8) and into the first cylinder
116.
[0034] A second inlet check valve 164 can be associated with the
second cylinder 118 and can
be selectively operable in either an open state or a closed state. When in the
closed state, the distal
perimeter portion of the circularly extending flap of the second inlet check
valve 164 can be sealed
over openings 165 (see FIG. 8) that extend to the inlet chamber 158 to
substantially seal and
prevent fluid flow from the second cylinder 118 into the inlet chamber 158.
When in the opened
state, the distal perimeter portion of the circularly extending flexible flap
of the second inlet check
valve 164 can be outwardly biased, thereby permitting fluid flow from the
inlet chamber 158,
through the openings 165 (FIG. 8) and into the second cylinder 118. In one
embodiment, the first
and second inlet check valves 160, 164 can each comprise an umbrella valve
having a generally
circularly extending flexible flap that can move from a closed position and an
open position. It is
to be appreciated that any of a variety of suitable alternative inlet check
valve configurations are
contemplated.
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[0035] Still referring to FIG. 9A, the first and second cylinders
116, 118 have at their
respective distal ends a first outlet opening 172 (also shown in FIG. 8) and a
second outlet opening
176, respectively. The first and second outlet openings 172, 176 can be in
fluid communication
with the outlet chamber 159 (FIG. 7), which is in turn in fluid communication
with the outlet port
156. A first outlet check valve 174 can be associated with the first cylinder
116 and can be
selectively operable between an opened position and a closed position. When in
the closed position,
the first outlet check valve 174 can be in contact with a valve seat 197 (FIG.
9B) to provide a seal
therebetween that prevents fluid flow from the first cylinder 116 into the
outlet chamber 159. When
in the opened position, the first outlet check valve 174 can be spaced from
the valve seat 197 (and
can rest against a valve stop 194) to allow fluid flow from the first cylinder
116 into the outlet
chamber 159. The first outlet check valve 174 can be biased into the closed
position by a spring
184.
[0036] A second outlet check valve 178 can be associated with the
second cylinder 118 and
can be selectively operable between an opened position and a closed position.
When in the closed
position, the second outlet check valve 178 can be in contact with a valve
seat 199 to provide a
seal therebetween that prevents fluid flow from the second cylinder 118 into
the outlet chamber
159. When in the opened position, the second outlet check valve 178 can be
spaced from the valve
seat 199 (and can rest against a valve stop 196) to allow fluid flow from the
second cylinder 118
into the outlet chamber 159. The second outlet check valve 178 can be biased
into the closed
position by a spring 186.
[0037] In one embodiment, the first and second outlet check valves
174, 178 can comprise a
plunger valve. In other embodiments, the first and second outlet check valves
174, 178 can be any
other type of plug or valve having any of a variety of sizes and shapes that
facilitate sealing contact
with valve seats (e.g., 197,199). It is to be appreciated that any of a
variety of suitable alternative
check valves are contemplated.
[0038] In one embodiment, the first piston 112 and the second
piston 114 do not permit fluid
to pass out of their respective cylinders 116, 118 except through one of the
outlet check valves
174, 178. The outlet check valves 174, 178 may be generally disposed toward
the upper cover 111,
near the inlet port 152 and outlet port 156, both of which are disposed on one
end (e.g., the distal
end) of the cylinders 116, 118. That is, in one embodiment, the pistons 112,
114 are solid, such
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that fluid does not pass through the pistons 112, 114, but is drawn into the
cylinders 116, 118 and
displaced out of the cylinders 116, 118 without being in contact with any
other pump components
other than the inlet port 152 and the outlet port 156, both of which include
fluid paths (e.g., through
the inlet and outlet chambers 158, 159) generally leading to or from the top
of the cylinders, that
is, the distal end of the cylinders 116, 118 nearest the upper cover Ill.
[0039] The first and second inlet check valves 160, 164 and the
first and second outlet check
valves 174, 178 can cooperate with the first and second pistons 112, 114 to
facilitate pumping of
fluid from the inlet port 152 to the outlet port 156. For example, when the
first piston 112 travels
along its exhaust stroke (e.g., from a bottom dead center position in the
direction of arrow 177 to
the top dead center position shown in FIG. 9A), the pressure generated in the
first cylinder 116
can urge the first inlet check valve 160 into the closed state while
simultaneously urging the first
outlet check valve 174 into the opened position (in the direction of arrow
180). The fluid disposed
in the first cylinder 116 during the exhaust stroke can accordingly be urged
through the first outlet
opening 172, around the first outlet check valve 174 (along the path 188), to
the outlet chamber
159 and out of the outlet port 156. The second piston 114 can travel along its
intake stroke (e.g.,
from a top dead center position in the direction of arrow 179 to the bottom
dead center position
shown in FIG. 9A) simultaneously with the first piston 112. The resulting
pressure generated in
the second cylinder 118 can urge the second inlet check valve 164 into the
opened state while
simultaneously urging the second outlet check valve 178 into the closed
position (in the direction
of arrow 182). The fluid at the inlet port 152 can accordingly be drawn into
the inlet chamber 158,
through the opening 165 (in the direction of arrow 190 in FIG. 8), around the
second inlet check
valve 164 (along the path 170), and into the second cylinder 118 to
effectively fill the second
cylinder 118 with fluid.
[0040] Once the first and second pistons 112, 114 reach the top
dead center and bottom dead
center positions, respectively, shown in FIG. 9A, they can then reverse
direction towards an intake
stroke (in the direction of arrow 181) and an exhaust stroke (in the direction
of arrow 183),
respectively. When the first piston 112 travels along its intake stroke (e.g.,
from the top dead center
position shown in FIG. 9A to the bottom dead center position), the pressure
generated in the first
cylinder 116 can urge the first inlet check valve 160 into the open state
while simultaneously urging
the first outlet check valve 174 into the closed position (opposite the
direction of arrow 180). The
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fluid at the inlet port 152 can accordingly be drawn into the inlet chamber
158, through the opening
163 (in the direction of arrow 191 in FIG. 8), around the first inlet check
valve 160, and into the
first cylinder 116 to effectively fill the first cylinder 116 with fluid.
[0041] The second piston 114 can travel along its exhaust stroke
(e.g., from the bottom dead
center position as shown in FIG. 9A to the top dead center position)
simultaneously with the first
piston 112. The resulting pressure generated in the second cylinder 118 can
urge the second inlet
check valve 164 into the closed state while simultaneously urging the second
outlet check valve
178 into the opened position (opposite the direction of arrow 182). The fluid
disposed in the second
cylinder 118 during the exhaust stroke can accordingly be urged through the
second outlet opening
176, around the second outlet check valve 178, to the outlet chamber 159 and
out of the outlet port
156. The first and second pistons 112, 114 can continue to operate in this
manner to facilitate
pumping of fluid from the inlet port 152 to the outlet port 156.
[0042] Referring now to FIGS. 2 and 9C, in one example embodiment,
the pump assembly
100 includes a pressure control member 202 that can limit the pressure of
fluid exiting the pump
assembly 100 to a predetermined pressure. Fluid can enter the inlet port 157
of the inlet connector
153 in the direction of arrow 204, and exit the outlet port 156 in the
direction of arrow 206. The
fluid path follows that described above, i.e., into the cylinders 116, 118
from the inlet chamber
158, and out of the cylinders 116, 118 to the outlet port 156. In an
embodiment, an output tube 458
(FIG. 11) having a nozzle (not shown) can be attached to the outlet port 156
to provide a fluid path
from the outlet port 156 to the nozzle. The nozzle may have a structure that
restricts fluid flow,
which creates back pressure. The volume of fluid, and in turn, the back
pressure may be reduced
or controlled to a predetermined value. The pressure control member 202 can
facilitate control of
the back pressure to a maximum, or otherwise predetermined, value by serving
as an overpressure
relief check valve that permits fluid at a predetermined pressure to flow
through a pressure relief
channel 260 from the outlet port 156 back to the inlet port 152, in the
direction indicated by the
arrow 212.
[0043] Still referring to FIG. 9C, in one embodiment, the pressure
control member 202 can
include a spring biased plunger 155 that sealingly seats against a valve seat
161 in the pressure
control member 202 to prevent fluid flow from the outlet port 156 to the inlet
port 152. The plunger
155 is biased against the valve seat 161 by a spring 154, which can be a coil
spring that presses
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with a predetermined force on the plunger 155. In some embodiments, such as
the one shown in
FIG. 2, the pressure control member 202 can include the inlet connector 153,
which is configured
to provide an opposing force against a portion of the spring 154 distal to the
portion of the spring
154 that contacts the plunger 155. The plunger 155 can prevent fluid from
flowing from the outlet
port 156 to the inlet port 152 unless and until the pressure of the fluid in
the outlet port 156 is
sufficient to cause the spring 154 to compress, and, therefore, the plunger
155 to be separated from
the valve seat 161, thus permitting fluid flow from the outlet port 156 to the
inlet port 152 in the
direction of arrow 212, thereby reducing the back pressure at the nozzle. Once
the back pressure
at the nozzle is reduced to the predetermined maximum pressure or below, the
spring force of the
spring 154 urges the plunger 155 against the valve seat 161, and remains
sealingly seated until the
back pressure once again causes unseating, and fluid flow in the direction of
arrow 212. The
pressure control member 202 can continuously cycle from a closed valve
condition to an open
valve condition to keep the back pressure at the nozzle relatively constant
during use of the pump
assembly 100. It is to be appreciated that the plunger 155 can be any other
type of plug or valve
having any of a variety of sizes and shapes that facilitate sealing contact
with a valve seat (e.g.,
161).
[0044] In a method of operation, fluid from a supply reservoir,
such as a bottle, tank, or the
like, can be dispersed in a controlled manner utilizing the pump assembly 100
described herein,
for example, through a hand-held wand joined to the outlet port. In an
embodiment, a supply
reservoir can be connected in fluid communication to the inlet port 152, such
as by a flexible tube.
As the actuator 130 rotates, for example, by being driven by the motor 102 in
rotational motion,
the cam path 136 rotates to force the pistons, coupled by their respective cam
followers, into a
reciprocal linear motion, with each piston being 180 degrees out of phase with
the other. As a
piston retracts, such as depicted in FIGS. 9A and 9B with second piston 114, a
partial pressure is
created in the cylinder. The partial pressure acts to cause the inlet check
valve to open, thereby
drawing fluid from the supply reservoir, through the inlet port, and into the
cylinder. As a piston
advances, such as depicted in FIGS. 9A and 9B with first piston 112, the
pressure induced on the
fluid in the cylinder both closes the inlet check valve and forces open the
outlet check valve to
permit the fluid in the cylinder to be forced out to the outlet port. In an
embodiment, a handheld
wand in fluid communication with the outlet port can be manipulated to direct
dispersed fluid from
a wand nozzle, for example.
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[0045] With reference to FIG. 10, the pump assembly 100 can be part
of a hand-held fluid
dispenser 300, in one embodiment. The hand-held fluid dispenser 300 can be of
the type known to
be used with commercially available herbicides. As shown in FIG. 10, the pump
assembly 100 and
the motor 102 can be mounted into a handle body 302, which can be a molded
plastic handle. The
handle body 302 can include a power supply for the motor 102, such as, for
example, one or more
batteries 304. A depressible trigger member 306 can be spring-biased by a
spring 308 into an
extended position, in which an electrical circuit connecting power from the
batteries 304 via
electrical conductors 310 to the electrical connections 104 is open. When the
trigger member 306
is urged against the spring force of the spring 308 a sufficient distance, the
electrical circuit is
closed, permitting power from the batteries 304 to energize the motor 102,
which in turn causes
rotational motion of the actuator 130. Rotational motion of the actuator 130
causes the
reciprocating motion of the pistons and the resulting fluid movement from the
inlet port to the
outlet port, as described herein.
[0046] In a method of operation, as depicted schematically in FIG.
11, the hand-held fluid
dispenser 300 can be used to pump fluid 450 from a supply reservoir 452, such
as a bottle, tank,
or the like. The fluid 450 can be drawn in the direction of arrow 400 into a
supply tube 456, which
can be a flexible tube. The supply tube 456 extends into the supply reservoir
452 to a connection
at the inlet port 152, as described above. In an embodiment, the supply tube
456 is coupled to the
inlet connector 153. The fluid 450 can be dispersed in a controlled manner
utilizing the pump
assembly 100 through the output tube 458 joined to the outlet port 156. Fluid
can be dispensed
from a distal end of the output tube 458 in the direction of arrow 460. In
operation, the actuator
130 rotates, for example, by being driven by the motor 102 in rotational
motion, thus rotating the
cam path 136 to force the pistons, coupled by their respective cam followers,
into a reciprocal
linear motion, with each piston being 180 degrees out of phase with the other.
As a piston retracts,
such as depicted in FIGS. 9A and 9B with second piston 114, a partial pressure
is created in the
cylinder. The partial pressure acts to cause the inlet check valve to open,
thereby drawing fluid
from the supply reservoir 452, through the supply tube 456 and to the inlet
port 152, and into one
of the cylinders 116, 118. As a piston advances, such as depicted in FIGS. 9A
and 9B with first
piston 112, the pressure induced on the fluid in the cylinder both closes the
inlet check valve and
forces open the outlet check valve to permit the fluid in the cylinder to be
forced out to the outlet
port. In an embodiment, the output tube 458 coupled in fluid communication
with the outlet port
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156 can be a handheld wand that can be manipulated to direct dispersed fluid
from a wand nozzle,
for example.
[0047] The foregoing description of embodiments and examples has
been presented for
purposes of illustration and description. It is not intended to be exhaustive
or limiting to the forms
described. Numerous modifications are possible in light of the above
teachings. Some of those
modifications have been discussed, and others will be understood by those
skilled in the art. The
embodiments were chosen and described in order to best illustrate principles
of various
embodiments as are suited to particular uses contemplated. The scope is, of
course, not limited to
the examples set forth herein, but can be employed in any number of
applications and equivalent
devices by those of ordinary skill in the art. Rather it is hereby intended
the scope of the invention
to be defined by the claims appended hereto.
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