Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02797154 2012-11-28
LIQUID METERING AND INJECTION SYSTEM
BACKGROUND
[0001] The present invention relates to liquid metering, measuring, and
dispensing, and
particularly to metering and measuring liquid products for use in industrial
or commercial laundry
facilities.
[0002] Large capacity industrial and commercial laundry facilities utilize
washing machines
having capacities on the order of 100 lbs. or more of laundry. Depending upon
the type of
laundry, different types and amounts of detergent, chemicals, and cleaning
solutions are used
during different stages in the washing operation. Because the sizes of washers
and the sizes of
individual loads of laundry can vary throughout a commercial washing facility
and from load to
load, it is desirable to have an automated system for dispensing the correct
amount of detergent
and cleaning solutions for each system and each load.
[0003] Known systems for regulating the various chemicals and liquids used in
commercial
laundry facilities rely upon in-line flow meters to measure the flow rate of a
given liquid through
a given conduit. When the flow rate is known, the total amount of liquid
dispensed by the
system can be controlled by regulating the duration of the flow. Because
different liquids have
different viscosities and are carried by different conduits, it generally is
required to have
individual flow meters for each type of liquid that is to be supplied to the
washing machine. As a
result, each flow meter must be individually calibrated for the specific
liquid being measured.
Moreover, because flow meters are highly sensitive to pressure changes,
cavitation, and other
flow irregularities, the pumps used to initiate the flow of the liquids
through the conduits must be
of a type that provides a uniform and relatively consistent output flow. For
example, peristaltic
pumps have been successfully used in commercial laundry facilities.
SUMMARY
[0004] During use in commercial laundry facilities, a flow meter may introduce
errors as air
enters the delivery tubes or if the supply pump connected to the flow meter
generates a back
pressure to the flow meter. Errors in the flow meter may result in under-
delivering or over-
delivering the chemicals and liquids. Under-delivering the chemicals and
liquids may result in
ineffective cleaning, while over-delivering may result in wasting the
chemicals and liquids, and
potentially damage the loads of laundry.
CA 02797154 2012-11-28
[0005] In an aspect the disclosure relates to a liquid metering system for a
commercial or
industrial laundry operation that can measure a weight of a cleaning solution
that is being
transferred. The system generally includes a dosing tank configured to receive
the cleaning
solution, a weight sensor configured to measure a weight of the cleaning
solution received by
the dosing tank, and a discharge pump operable to pump the measured cleaning
solution from
the transport tank to downstream equipment.
[0006] In another aspect the disclosure relates to a metering assembly for a
commercial or
industrial laundry operation that can measure a weight of a cleaning solution
that is being
transferred. The metering assembly generally includes a dosing tank configured
to receive the
cleaning solution, and a weight sensor configured to measure a weight of the
cleaning solution
received by the dosing tank.
[0007] Aspects of the invention will become apparent by consideration of the
detailed
description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Fig. 1 is a perspective view of a liquid metering and injection system
embodying the
invention.
[0009] Fig. 2 is a perspective view of a frame of the liquid metering and
injection system of
Fig. 1.
[0010] Fig. 3 is an enlarged perspective view of a portion of the frame of
Fig. 2.
[0011] Fig. 4 is a perspective view of a metering assembly of the liquid
metering and
injection system of Fig. 1.
[0012] Fig. 5 is an exploded perspective view of the metering assembly of Fig.
4.
[0013] Fig. 6 is a perspective view of an injection cap of the metering
assembly of Fig. 4.
[0014] Fig. 7 is a perspective view of a load cell of the metering assembly of
Fig. 4.
[0015] Figs. 8a, 8b, and 8c are top, side, and perspective views,
respectively, of a load cell
bracket of the metering assembly of Fig. 4.
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[0016] Fig. 9. is a perspective view of a load cell bracket cover of the
metering assembly of
Fig. 4.
[0017] Fig. 10 is a perspective view of a dosing tank of the metering assembly
of Fig. 4.
[0018] Fig. 11 is a perspective view of a transport tank of the metering
assembly of Fig. 4.
[0019] Fig. 12 is a perspective view of a transport tank lid of the metering
assembly of Fig.
4.
[0020] It is to be understood that the invention is not limited in its
application to the details of
the construction and the arrangements of components set forth in the following
description or
illustrated in the drawings. The present invention is capable of other
embodiments and of being
practiced or being carried out in various ways. Also, it is to be understood
that the phraseology
and terminology used herein is for the purpose of description and should not
be regarded as
limiting.
DETAILED DESCRIPTION
[0021] Fig. 1 illustrates a liquid metering and injection system 10. The
system 10 includes a
lower pumping cabinet 14, an upper control cabinet 18 mounted above the
pumping cabinet 14,
and a metering assembly 22 supported on one side of the pumping cabinet 14.
The pumping
cabinet 14 houses pumps and manifolds for distributing cleaning solutions,
which typically are in
liquid form and include different concentrations of various chemicals and
compounds for
obtaining a specific cleaning goal. As used herein, the term "cleaning
solution" shall refer to any
liquid pumped and distributed by the system 10 without regard to its specific
composition or
ultimate purpose. The control cabinet 18 includes electronic circuitry and
control systems for
controlling operation of the pumps and manifolds, and the metering assembly 22
measures
specific quantities of cleaning solution for distribution to downstream
equipment (not shown),
such as commercial or industrial laundry equipment.
[0022] The pumping cabinet 14 includes an upper shelf 26 and a middle shelf 30
each
supporting a plurality (e.g., six as illustrated) of pumps 34 configured to
pump cleaning solution.
Each pump 34 is coupled to a supply tank (not shown) for a different cleaning
solution and is
operable to pump its respective cleaning solution to the metering assembly 22.
The pumping
cabinet 14 also includes a lower shelf 38 that supports three additional
pumps, including a first
water flush pump 42, a second water flush pump 46, and a discharge pump 50. In
the
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illustrated construction, the pumps 34, 42, 46, and 50 are diaphragm pumps,
chosen based at
least in part upon their relatively low cost, long life, and good reliability.
Those skilled in the art
will readily appreciate that other types of pumps could also be used without
departing from the
spirit and scope of the present invention. A plurality of manifolds 54 are
mounted below the
middle shelf 30 and to the left of the discharge pump 50. The discharge pump
50 is coupled at
its input to the metering assembly 22 for receiving metered amounts of
cleaning solution(s)
therefrom, and is coupled at its output to the manifolds 54 for controlling
distribution of the
metered cleaning solution(s) to the downstream commercial washing equipment.
[0023] Referring also to Fig. 2, the pumping cabinet 14 includes a frame 58
for supporting
the various components of the system 10. The illustrated frame 58 includes
base members 62
engaging the ground, uprights 64 extending upwardly from the base members 62,
and a
plurality of cross beams 66 extending between the uprights 64. The right hand
side of the frame
58 includes an upper extension 68 extending outwardly from the side of the
frame 58, and a
lower extension 70 below the upper extension. The upper and lower extensions
68, 70
cooperate to support the metering assembly 22.
[0024] Fig. 3 illustrates the upper and lower extensions 68, 70 in further
detail. Each
extension 68, 70 is substantially U-shaped. The upper extension 68 includes a
pair of side legs
72 extending away from the frame 58 and a base leg 74 extending between the
side legs 72.
Each side leg 72 includes a top hole 76 substantially centered along the
length of the side leg
72, and a pair of inwardly-facing, spaced-apart, side holes 78 that face
inwardly (only the side
holes 78 of the rear side leg 72 are visible in Fig. 3). The base leg 74 of
the upper extension 68
also includes a pair of inwardly-facing side holes 78. In some constructions,
side holes 78 and
the top hole 76 may have crimps in threaded inserts.
[0025] The upper extension 68 also includes a central support member 80
extending
substantially parallel to the side legs 72 from the cross beam 66 of the frame
to the base leg 74.
The central support member 80 is substantially centered between the side legs
72 and is
coupled (e.g., by welding) to the undersides of the cross beam 66 and the base
leg 74. The
central support member 80 includes a pair of mounting holes 82 on an underside
thereof (the
mounting holes 82 are showing facing upwardly in Fig. 3 to show their
approximate location
along the central support member 80, but in fact face downwardly when the
system 10 is
properly assembled). The lower extension 70 is also substantially U-shaped and
includes a pair
of side legs 84 extending away from the frame 58 and a base leg 86 extending
between the side
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legs 84. Each side leg 84 includes a top hole 88 substantially centered along
the length of the
side leg 72.
[0026] Referring also to Figs. 4 and 5, the metering assembly 22 is configured
to receive
one or more cleaning solutions from the pumps 34, measure by weight a specific
amount of
cleaning solution or solutions, and discharge the measured amount of cleaning
solution or
solutions to the discharge pump 50. Some or all components of the metering
assembly 22 may
be made of stainless steel or ethylene tetrafluoroethylene (ETFE) coated
aluminum. However,
the apparatus and articles of manufacture described herein are not limited in
this regard.
[0027] Referring also to Fig. 6, the metering assembly 22 includes a dosing
cap 90 that is
coupled to and supported by the upper extension 68. The dosing cap 90 includes
a floor 92
having formed therein a plurality of apertures 94 sized and arranged to
receive nozzles and
conduits that are coupled to the various pumps 34. The illustrated dosing cap
90 also includes
four sidewalls 96, with two of the sidewalls 96 defining opposed load openings
98 positioned
near the floor 92. As explained below, the remaining two sidewalls 96 each
define an upwardly
opening slot 102 that receives a respective end 110, 112 of a weight sensor
108 when the
dosing tank is supported from the frame 58 by way of the weight sensor 108.
[0028] Although in the illustrated embodiment includes two sidewalls 96 each
defining the
upwardly opening slot 102, other embodiments may include a single sidewall 96
defining the
upwardly opening slot 102. An open side (not shown) of the dosing cap 90 may
then face
toward the pumping cabinet 14 when the dosing cap 90 is coupled to the upper
extension 68
and accommodate the various conduits extending between the pumps 34 and the
nozzles that
are received by the apertures 94 of the dosing cap 90. In the illustrated
embodiment without the
open side, one of the sidewalls 96 defining the upwardly opening slot 102 also
defines a
plurality of apertures 94 formed therein sized and arranged to accommodate the
various
conduits and nozzles.
[0029] Each sidewall 96 defines a pair of holes 106 along an upper edge
thereof that are
configured for alignment with the inwardly-facing side holes 78 in the upper
extension.
Fasteners (not shown) extend through the holes 106 and into the side holes 78
secure the
dosing cap 90 to the upper extension 68. A dosing lid 107 covers the dosing
cap 90. The
dosing lid 107 fits over and is coupled to the top holes 88 provided in the
side legs 84 of the
upper extension 68.
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[0030] Referring also to Fig. 7, the metering assembly 22 further includes a
weight sensor
or load cell 108 having a first end 110 coupled to the central support member
80 and a second
end 112 that supports other portions of the metering assembly 22. The first
and second ends
110, 112 of the load cell each include a pair of openings 114 for securing the
load cell 108 to
other components. The illustrated load cell 108 also includes a central
sensing portion 116 that
includes sensors 118 (e.g., strain gauges) configured to measure the load that
is supported by
the load cell 108. The illustrated load cell 108 is an OMEGA brand LCAE-25KG
load cell,
however those skilled in the art will readily appreciate that other types,
brands, and sizes of load
cells or load/force measurement devices could also be used without departing
from the spirit
and scope of the present invention.
[0031] A weight sensor bracket or load cell bracket 120 (Figs. 8a, 8b, 8c) is
coupled to the
second end 112 of the load cell 108. The illustrated load cell bracket 120 is
a cylindrical rod and
extends outwardly and away from the load cell 108. The load cell bracket 120
includes a
centrally-located flat 122 and central bores 124 for coupling to the second
end 112 of the load
cell 108. Each end of the load cell bracket 120 includes an axially-aligned
threaded bore 126,
and a small overhanging tab 128. As shown in Figs. 4 and 5, a pair of load
cell bracket covers
129 (Fig. 9) are coupled to the dosing cap 90 and cover the portions of the
load cell bracket 120
that extend outwardly and away from the load cell 108. The load cell bracket
covers 129 ensure
that the conduits and other components coupled to and extending from the
dosing cap 90 do not
contact the load cell bracket 120, thereby eliminating a potential source of
errors in the readings
taken by the load cell 108.
[0032] The load cell bracket 120 supports a dosing tank 130 that receives and
contains the
cleaning solutions dispensed from the nozzles that are coupled to the dosing
cap 90. As shown
in Fig. 10, the dosing tank 130 includes sidewalls 132, two of which define
opposed openings
134. The dosing tank 130 also includes downwardly and inwardly sloping
interior walls 138 that
act as a funnel and terminate at a bottom wall 142 defining a discharge
opening 146. In the
illustrated embodiment, the dosing tank 130 also includes a splash guard 147
therein. In other
embodiments, however, the dosing tank 130 may not include the splash guard
147.
[0033] With reference also to Figs. 4 and 5, the ends of the load cell bracket
120 extend
through and slightly beyond the opposed load openings 98 in the dosing cap 90.
To couple the
dosing tank 130 to the load cell bracket 120, the dosing tank 130 is moved
upwardly and over
the bottom portion of the dosing cap 90, which as noted above is coupled to
and supported by
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the upper extension 68. The openings 134 in the dosing tank sidewalls 132 are
then aligned
with the axially-aligned threaded bores 126 of the load cell bracket 120.
Fasteners (not shown)
are then extended through the openings 134 and threaded into the threaded
bores 126 to
couple the dosing tank 130 to the ends of the load cell bracket 120. The
overhanging tabs 128
on the ends of the load cell bracket 120 fit over the ends of the dosing tank
sidewalls 132 to
prevent rotation of the dosing tank 130 with respect to the load cell bracket
120 (see Fig. 4).
The dosing tank 130 is sized to loosely receive the lower portion of the
dosing cap 90.
Furthermore, the load cell openings 98 in the sidewalls of the dosing cap 90
are larger than the
load cell bracket 120 such that the load cell bracket 120 extends through the
openings 98
without contacting the load cell openings. In this regard, even though the
dosing tank 130
receives the dosing cap 90 and is in close proximity thereto, the dosing cap
90 is supported
more or less directly and exclusively by the frame 58, whereas the dosing tank
130 is supported
from the frame 58 by way of the load cell 108 and load cell bracket 120.
Because the dosing
tank 130 is supported from the second end 112 of the load cell 108, the load
cell 108 is able to
measure the weight of the dosing tank 130 and any cleaning solutions dispensed
into the dosing
tank 130.
[0034] Although in the illustrated embodiment the weight sensor 108 is a load
cell coupled
to the load cell bracket 120, in other embodiments other structures performing
the same
function as the load cell 108 disclosed herein can be used instead. For
example, in some
embodiments the weight of the cleaning solution received by the dosing tank
130 may be
measured by a sensor pad supporting an underside of the dosing tank 130. In
some
embodiments, the weight sensor 108 may include any mechanical assembly
configured to
measure the weight of the cleaning solution received by the dosing tank 130.
In other
embodiments, the weight sensor 108 may include a piezoelectric compression
sensor or any
other electric sensors depending on the usage requirements or preferences for
the liquid
metering and injection system 10. Moreover, although the illustrated
embodiment includes a
single weight sensor 108, other embodiments may include a plurality of weight
sensors 108, for
example so as to reliably and accurately measure the weight of the cleaning
solution.
[0035] As shown in Figs. 4 and 5, a valve assembly 148 is coupled to and
supported by the
dosing tank 130. The valve assembly 148 includes an inlet 149 coupled to the
discharge
opening 146 and can be closed and opened to either retain and collect cleaning
solution in the
dosing tank 130 or to allow cleaning solution to flow out of the dosing tank
130. The illustrated
valve assembly 148 includes an air-operated diaphragm valve 150 that can be
operated by
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pressurized air. Those skilled in the art will readily appreciate that other
types of valves could
also be used without departing from the spirit and scope of the present
invention. When the
valve 150 is closed, cleaning solution collects in the dosing tank 130. When
the valve 150 is
opened, cleaning solution flows by gravity feed out of the dosing tank 130,
through the valve
assembly 148 and out a discharge tube 152 that extends downwardly from the
valve 150.
Because the valve assembly 148 is supported by the dosing tank 130, the mass
of the valve
assembly 148 is included in the overall load that is supported by the load
cell 108.
[0036] Referring also to Figs. 11 and 12, the discharge tube 152 of the valve
assembly 148
discharges cleaning solution into a transport tank 154 that is coupled to and
supported by the
lower extension 70 of the frame 58. A transport tank lid 156 is also coupled
to the lower
extension 70, covers the transport tank 154, and defines an opening 158
through which the
discharge tube 152 extends. In some embodiments, the discharge tube 152 may
include a
through-pipe rubber grommet (not shown) that creates a light seal between the
discharge tube
152 and the opening 158 in the transport tank lid 156 without affecting the
movement of the
dosing tank 130. In this way, the dosing tank 130 and valve assembly 148 are
supported
substantially exclusively by the load cell 108 and the load cell bracket 120.
Like the dosing tank
130, the transport tank 154 also includes downwardly and inwardly sloping
interior walls 160
(Fig. 11) that act as a funnel and guide cleaning solution(s) in the transport
tank 154 toward a
centrally located discharge opening (not shown) in the bottom of the transport
tank 154. A
conduit 162 (Fig. 1) extends from the bottom of the transport tank 154 and is
coupled to the
discharge pump 50, which pumps cleaning solution(s) from the transport tank
154 to the
manifolds 54 for distribution to the downstream equipment.
[0037] In the above-described metering assembly 22, the load cell 108 supports
the load
cell bracket 120, the dosing tank 130, and the valve assembly 148. The dosing
cap 90 and
dosing lid 107 are supported by the upper extension 68, and the transport tank
154 and
transport lid 156 are supported by the lower extension 70. Thus, as cleaning
solution is
dispensed into the dosing tank 130, the weight supported by the load cell 108
increases in
proportion to the volume of solution that is dispensed, allowing for an
accurate measurement of
cleaning solution volume for subsequent discharge to downstream equipment.
[0038] In use, the control system housed in the control cabinet 18 responds to
operator or
automated requests for dispensing a specific cleaning solution by operating
the metering
assembly 22 to measure the appropriate quantity of the specific cleaning
solution. To measure
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a specific quantity of a given cleaning solution, the diaphragm valve 150 is
closed and the pump
34 associated with the cleaning solution is turned on. Turning on the pump 34
pumps cleaning
solution through conduits in the pumping cabinet 14 to the corresponding
discharge nozzle (not
shown) that is coupled to the floor 92 of the dosing cap 90. The cleaning
solution is then
discharged into the dosing tank 130. Because the diaphragm valve 150 is
closed, the cleaning
solution begins to accumulate in the dosing tank 130, and the load on the load
cell 108 begins
to increase.
[0039] The densities of the various cleaning solutions pumped by the system 10
are pre-
programmed into the control system. As such, the control system is able to
monitor the weight
of the cleaning solution via the load readings provided by the load cell 108,
and can then
convert the weight of the cleaning solution into a volume of cleaning solution
that has been
dispensed. In some applications, overall cycle time of the system 10 can be
reduced by
constantly monitoring the load on the load cell 108 and adjusting the speed of
the pump 34 on
the fly. For example, at the beginning of a discharge cycle the pump 34 can be
operated at
maximum speed to rapidly fill the dosing tank 130. However, as the desired
quantity of cleaning
solution is approached, the speed of the pump 34 can be reduced to allow the
final amount of
cleaning solution dispensed to be controlled more precisely.
[0040] Once the desired amount of cleaning solution has been transferred to
the dosing
tank 130, the pump 34 is turned off and the diaphragm valve 150 is opened. The
cleaning
solution then flows by gravity through the discharge tube 152 and into the
transport tank 154.
As the cleaning solution is flowing into the transport tank 154, the control
system can continue
to monitor the load on the load cell 108 and thus be able to detect when the
dosing tank 130 is
completely empty. When the dosing tank 130 is empty, the diaphragm valve 150
is closed and
another metered dose of cleaning solution can be prepared, potentially before
the previously-
metered dose of cleaning solution has been pumped from the transport tank 154
by the
discharge pump 50. For certain operating parameters, it may also be desirable
to mix metered
amounts of different cleaning solutions in the transport tank 154 before the
transport tank 154 is
emptied by the discharge pump 50. Once the final desired amount of cleaning
solution or
solutions have been transferred to the transport tank 154, the discharge pump
50 is operated
and the manifolds 54 are controlled to supply the metered and optionally pre-
mixed cleaning
solution(s) to the appropriate downstream equipment.
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[0041] The system 10 is advantageously configured to dispense a plurality of
different
cleaning solutions (e.g., twelve in the illustrated embodiment). In some
circumstances, these
different cleaning solutions may be dangerously reactive with one another. To
reduce potential
risks associated with the mixing of incompatible cleaning solutions, the first
and second water
flush pumps 42, 46 can be used to rinse the dosing tank 130 and the transport
tank 154,
respectively. The first water flush pump 42 is connected via conduits to the
dosing cap 90 and
is operable to pump rinse water into the dosing tank 130. The second water
flush pump 46 is
connected via conduits to the transport tank 154 or transport tank lid 156,
and is operable to
pump rinse water into the transport tank 154. In some embodiments, the control
system can be
pre-programmed to recognize potentially dangerous combinations of cleaning
solutions and to
rinse the dosing tank 130 and/or the transport tank 154 as needed between
metering
operations.
[0042] The system 10 may also include a self-calibration feature that utilizes
a float
assembly mounted to the dosing cap 90. The float assembly extends or can be
adjusted to
extend downwardly from the dosing cap 90 to sense a location of the free
surface of any liquid
contained within the dosing tank 130. Thus, the control system can fill the
dosing tank 130 with
a liquid of known density (e.g., water) to a predetermined calibration level
having a known
volume by sensing the level of the liquid with the float assembly. The control
system can then
compare the reading of the load cell 108 with the expected reading based upon
the known
volume and known density of the liquid that held in the dosing tank, and can
adjust the
calibration level of the load cell 108 as necessary. In other embodiments, the
self-calibration
feature may utilize an ultra sonic sensor or a sight glass instead of a float
assembly. In still
other embodiments, the system 10 may not include a self-calibration feature.
For example, a
known amount of liquid may be injected so as to eliminate the need for a self-
calibration feature.
The apparatus and articles of manufacture described herein are not limited in
this regard.
[0043] In view of the foregoing, the system 10 is operable to meter and
dispense a desired
amount of cleaning solution by measuring the weight of the cleaning solution
before dispensing
the cleaning solution to downstream equipment. The system 10 includes a dosing
tank 130
supported by a load cell 108. The system 10 is configured to minimize possible
interference
with readings of the load cell 108 by supporting at least the dosing cap 90
and the transport tank
154 by separate structure, such as the upper and lower extensions 68, 70.
Because the system
includes two tanks, namely the dosing tank 130 and the transport tank 154, a
first measured
quantity of cleaning solution can be prepared in the dosing tank 130 and
transferred to the
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,
transport tank 154. Then, before the first measured quantity of cleaning
solution is transferred
from the transport tank 154, a second measured quantity of cleaning solution
can begin to be
prepared in the now-empty dosing tank 130, thereby reducing overall cycle time
of the system.
The two tank arrangement also allow for the pre-mixing of multiple measured
quantities of
cleaning solutions in the transport tank 154. The system is also capable of
performing self-
calibration of the load cell 108 using a float assembly mounted to the dosing
cap 90.
[0044] It is understood that the disclosure may embody other specific forms
without
departing from the spirit or central characteristics thereof. The disclosure
of aspects and
embodiments, therefore, are to be considered as illustrative and not
restrictive. While specific
embodiments have been illustrated and described, other modifications may be
made without
significantly departing from the spirit of the invention.
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