U.S. patent application number 09/841316 was filed with the patent office on 2001-10-11 for cleaning system for a washer.
Invention is credited to Duchaine, Mario, Emond, Michel, Lemay, Michel, Parent, Ghislain, Rochette, Daniel, Theriault, Yves-Andre, Thibault, Nathalie.
Application Number | 20010027800 09/841316 |
Document ID | / |
Family ID | 25516898 |
Filed Date | 2001-10-11 |
United States Patent
Application |
20010027800 |
Kind Code |
A1 |
Rochette, Daniel ; et
al. |
October 11, 2001 |
Cleaning system for a washer
Abstract
A high pressure pump (14) supplies cleaning fluid from a
reservoir (12) to spray nozzles (20) inside a washing chamber (10).
The spray nozzles (20) spray the cleaning fluid over a load to be
cleaned. Used cleaning fluid is collected in a sump (30). A sump
pump (32) drains the sump. The combination of the high pressure
pump and sump pump provides more efficient cleaning of the load and
eliminates the requirement for a deep sump beneath the washer. A
vertical traveler (22), having a pair of counterbalanced spray arms
(24), raises and lowers the spray nozzles counter cyclically; a
detergent injection system (50) accurately meters a correct amount
of detergent is added to the cleaning fluid; and a filtration
device (34) filters suspended material from the used cleaning fluid
and uses a portion of the cleaning fluid to clean itself.
Inventors: |
Rochette, Daniel;
(Charlesbourg, CA) ; Lemay, Michel; (Ste-Foy,
CA) ; Theriault, Yves-Andre; (Beauport, CA) ;
Emond, Michel; (Levis, CA) ; Duchaine, Mario;
(Beauport, CA) ; Parent, Ghislain; (Cte-Levis,
CA) ; Thibault, Nathalie; (Boischatel, CA) |
Correspondence
Address: |
FAY, SHARPE, FAGAN
MINNICH & McKEE, LLP
Seventh Floor
1100 Superior Avenue
Cleveland
OH
44114
US
|
Family ID: |
25516898 |
Appl. No.: |
09/841316 |
Filed: |
April 24, 2001 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09841316 |
Apr 24, 2001 |
|
|
|
08970406 |
Nov 14, 1997 |
|
|
|
6257254 |
|
|
|
|
Current U.S.
Class: |
134/18 ; 134/108;
134/111; 134/113; 134/172; 134/199; 134/25.4; 134/34; 134/35;
134/36; 134/56R; 134/99.2 |
Current CPC
Class: |
B08B 3/02 20130101 |
Class at
Publication: |
134/18 ;
134/25.4; 134/34; 134/35; 134/36; 134/199; 134/108; 134/111;
134/99.2; 134/113; 134/56.00R; 134/172 |
International
Class: |
B08B 003/02 |
Claims
Having thus described the preferred embodiment, the invention is
now claimed to be:
1. A washer, the washer comprising: a washing chamber; spray
nozzles disposed in the washing chamber to spray a cleaning fluid
over a load to be cleaned; a sump at the bottom of the washing
chamber which collects the cleaning fluid sprayed over the load; a
sump pump which pumps cleaning fluid from the sump; a cleaning
fluid reservoir; a high pressure pump for pumping cleaning fluid
from the cleaning fluid reservoir to the spray nozzles.
2. The washer of claim 1 wherein the high pressure pump delivers
cleaning fluid to the spray nozzles at a pressure of about 5 to 15
bar.
3. The washer of claim 1, wherein the high pressure pump delivers
cleaning fluid to the spray nozzles at a pressure of 7-9 bar.
4. The washer of claim 2 wherein the cleaning fluid has a flow rate
of about 250 l/min.
5. The washer of claim 1 wherein the sump is a shallow sump, of
about 10 cm depth or less.
6. The washer of claim 1 wherein the sump pump is a self-priming
pump that operates at a low head of fluid.
7. The washer of claim 1 wherein the sump pump pumps cleaning fluid
to the cleaning fluid reservoir.
8. The washer of claim 1 wherein the sump includes: a sloping floor
which directs the cleaning fluid collected in the sump to the sump
pump.
9. The washer of claim 1 further including: an in-line temperature
booster which raises the temperature of the cleaning fluid from the
cleaning fluid reservoir to a preselected wash temperature shortly
before the cleaning fluid is delivered to the spray nozzles.
10. The washer of claim 1 further including: a filtration device
which selectively filters cleaning fluid drawn from the sump and
uses a portion of the cleaning fluid to clean the filtration device
of suspended material removed from the cleaning fluid by the
filter.
11. The washer of claim 10 wherein the filtration device further
includes: a fluid inlet which receives cleaning fluid drawn from
the sump; a first fluid outlet which directs unfiltered cleaning
fluid from the filtration device to a drain; a valve which
selectively closes to prevent cleaning fluid from exiting the
filtration device through the first fluid outlet; a filtration
screen which filters suspended material from the cleaning fluid;
and a second fluid outlet which directs cleaning fluid, filtered of
suspended material by the screen, to the cleaning fluid
reservoir.
12. The washer of claim 1 further including: a detergent injection
system which injects detergent into the cleaning fluid reservoir,
the detergent injection system including a supply of detergent and
a metering pump.
13. The washer of claim 12, wherein the detergent injection system
further includes: a flow meter, the flow meter detecting detergent
flow in the detergent injection system; and an alarm which
indicates when detergent flow through the flow meter drops below a
preselected level.
14. The washer of claim 12 further including: a water flow meter
for metering water added to the cleaning fluid reservoir; and a
control circuit to cause the metering pump to meter an amount of
detergent into the reservoir in proportion to the water added.
15. The washer of claim 14 wherein the amount of detergent added is
a function of a predetermined factor from a group including:
detergent concentration, level of soil on the load, type of
detergent, proportion of cleaning fluid reused, and type of
cycle.
16. The washer of claim 12 wherein the metering pump delivers a
number of pulses of detergent to the cleaning fluid tank, the
number of pulses determined by an amount of detergent to be
added.
17. The washer of claim 1, further including a vertical traveler
including: a pair of counterbalanced spray arms, disposed adjacent
opposite sides of the washing chamber, the spray nozzles disposed
on the spray arms; a mechanism which supports the spray arms for
vertical travel of the spray arms; and a drive system which
alternately raises and lowers the spray arms.
18. The washer of claim 17 wherein the drive system further
includes: a drive cable; and a drive means engaging the drive cable
and sequentially moving the cable alternately a preselected
distance in a first direction and an equivalent distance in a
second direction, the second direction being the reverse of the
first direction; the drive cable connected to the mechanism, the
cable defining a path from the drive means to each of the pair of
spray arms in turn and then to the drive means; whereby the
alternating movement of the cable causes first and second spray
arms to travel vertically in opposite directions.
19. The washer of claim 18 further including: a break-away
connection between the drive cable and the mechanism for
disconnecting the cable from the mechanism; and a safety cable
connected to the mechanism which prevents the pair of spray arms
from simultaneously moving in a downward direction.
20. A washer comprising: spray nozzles disposed within the chamber
for spraying a cleaning fluid into the chamber; a pump which pumps
cleaning fluid to the spray nozzles; a cleaning fluid reservoir
which supplies the pump with cleaning fluid; and a vertical
traveler including: first and second counterbalanced spray arms,
disposed adjacent opposite sides of the washing chamber, the spray
nozzles disposed on the spray arms; a mechanism which supports the
spray arms for vertical travel; and a drive system which
alternately raises and lowers the spray arms, the first spray arm
traveling in an opposite vertical direction to the second spray
arm.
21. A washer comprising: a washing chamber; spray nozzles disposed
within the chamber for spraying a cleaning fluid into the chamber;
a pump which pumps cleaning fluid to the spray nozzles; a cleaning
fluid reservoir which supplies the pump with cleaning fluid; and a
vertical traveler for alternately raising and lowering the spray
nozzles, the vertical traveler including: a drive system that
sequentially raises and lowers countercyclically a first set of
spray jets and a second set of spray jets.
22. The washer of claim 21 wherein the vertical traveler further
includes first and second spray arms disposed within the washing
chamber, the first spray arm disposed in facing opposition to the
second spray arm, the first set of spray nozzles disposed on the
first spray arm and the second set of spray nozzles disposed on the
second arm, the drive system alternatively raising and lowering the
spray arms.
23. The washer of claim 21 wherein the drive system includes: a
drive cable; and a drive means, the drive means engaging the drive
cable and alternatively moving the cable a preselected distance in
first and second directions, the first direction being opposite to
the second direction; the drive cable forming a closed loop which
passes from the drive means to the first set of spray nozzles and
then to the second set of spray nozzles before returning to the
drive means; whereby the alternative movement of the cable causes
first and second set of spray nozzles to travel vertically in
opposite directions.
24. The washer of claim 23 wherein the drive means includes a
rodless pneumatic pump.
25. A washer comprising: a washing chamber; spray nozzles disposed
in the washing chamber to spray a cleaning fluid over a load to be
cleaned; a cleaning fluid reservoir; a pump which pumps cleaning
fluid from the cleaning fluid reservoir to the spray nozzles; a
filtration device which removes suspended material from the
cleaning fluid, the device including: a fluid inlet which receives
cleaning fluid; a first fluid outlet which directs unfiltered
cleaning fluid from the filtration device to a drain; a valve which
selectively closes to prevent cleaning fluid from exiting the
filtration device through the first fluid outlet; a filtration
screen which filters suspended material from the cleaning fluid;
and a second fluid outlet through which filtered cleaning fluid
leaves the device.
26. The washer of claim 25, wherein the screen defines a cylinder
and is disposed in the filtration chamber with open ends of the
cylinder surrounding the first inlet and the outlet respectively,
the filtration device further including: first and second gaskets
disposed around the open ends to seal the screen to the filtration
chamber.
27. A fluid injection system for insuring accurate delivery of a
preselected quantity of a fluid, the fluid injection system
including: a peristaltic pump, the preselected quantity of fluid
measured in terms of a number of pulses of fluid delivered by the
pump; a flow meter which indicates whether fluid is flowing through
the pump, the flow meter detecting a flow of fluid in the fluid
injection system.
28. The fluid injection system of claim 27, the injection system
further including an alarm, the alarm indicating when the flow
meter detects a fluid flow below a preselected level.
29. The washer of claim 5 further including an in-line temperature
booster which raises the temperature of the cleaning fluid from the
cleaning fluid reservoir to a preselected wash temperature shortly
before the cleaning fluid is delivered to the spray nozzles,
whereby heating the cleaning fluid in the sump is avoided.
30. A method for cleaning cages and racks, the method comprising:
a) supplying spray nozzles with a cleaning fluid at a high
pressure; b) spraying the cleaning fluid from the spray nozzles
over a load of cages and racks; c) collecting sprayed cleaning
fluid in a sump; d) draining the cleaning fluid from the sump with
a sump pump.
31. The method of claim 30 further including before step a):
heating the cleaning fluid just before the cleaning fluid is
supplied to the nozzles.
32. The method of claim 30, step a) including: adding water to a
cleaning fluid reservoir; metering an amount of a detergent into
the cleaning fluid reservoir with a peristaltic pump; and pumping
the cleaning fluid at high pressure to the nozzles.
33. The method of claim 31, step a) further including: detecting a
flow of detergent with a flow meter, the flow meter indicating
whether detergent is flowing through the peristaltic pump.
34. The method of claim 31, step a) further including: controlling
the peristaltic pump with a control circuit, the control circuit
determining the amount of detergent to be added.
35. A cleaning system, the system comprising: supplying spray
nozzles with a cleaning fluid; spraying the cleaning fluid from the
spray nozzles over a load to be cleaned; sequentially raising and
lowering the spray nozzles with a vertical traveler, the sequence
including: raising a first set of the spray nozzles at the same
time as lowering a second set of the spray nozzles; lowering the
first set of the spray nozzles at the same time as raising the
second set of the spray nozzles.
36. A cleaning system, the system comprising: supplying spray
nozzles with a cleaning fluid at a high pressure; spraying the
cleaning fluid from the spray nozzles over a load to be cleaned;
collecting sprayed cleaning fluid; closing a filtration valve, the
valve connected to a first outlet on a filtration device; passing
the sprayed cleaning fluid into the filtration device; filtering
suspended material from the sprayed cleaning fluid; passing the
filtered cleaning fluid from the filtration device through a second
outlet; selectively opening the filtration valve; allowing a
portion of the sprayed fluid to pass through the first outlet and
through the open filtration valve to remove suspended material
trapped within the filtration device.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the cleaning and
disinfecting arts. It finds particular application in conjunction
with the cleaning of animal cages and racks and also healthcare and
scientific equipment, such as hospital beds, wheelchairs, utensils,
carts and instrument containers, and will be described with
particular reference thereto. It should be appreciated, however,
that the invention is also applicable to the cleaning and
disinfecting of other pieces of equipment, particularly those which
have been in contact with biological wastes.
[0002] Items such as animal cages and associated racks and large
pieces of healthcare and scientific equipment are generally cleaned
at frequent intervals to remove biological waste, such as urine,
feces, and uneaten food. Thorough cleaning aids in preventing the
spread of disease and reduces the development of unpleasant odors.
Washers have been developed to handle the large scale cleaning and
disinfecting of animal such items. Typically, these are large
enough for a load to be processed to be wheeled manually into the
washer. Cleaning fluid is then sprayed through jets onto the load.
The used fluid is collected in a pit or sump, below the washer. The
fluid is either recycled or discarded, depending on the degree of
contamination.
[0003] When large numbers of items are to be cleaned, the cycle
time of the machine is an important factor. A washer for items such
as cages is necessarily a large and invariably a costly investment,
and it is thus desirable for a facility to clean all such items in
a single washer. Typically, the jets which are used to spray
cleaning fluid over the load operate at around 20 p.s.i. (1.4 bar).
Stripping the often dried and adherent biological matter from the
load with fluid at this pressure is time consuming and cleaning
cycle times of 40 minutes or longer are common. In addition, low
pressure washing uses large quantities of cleaning fluid to
compensate for the low level of impingement of the sprays upon the
process load.
[0004] The length and effectiveness of the cleaning system are also
dependent on the arrangement of the jets within the washer. Cages
and racks and scientific and healthcare equipment and racks are
often large, with components which inhibit movement of the cleaning
fluid, resulting in incomplete cleaning of the load. A number of
systems have developed for directing the sprays of cleaning fluid
so as to improve coverage of the load. In one system, a rotary
spray arm is used. The pressure of the cleaning fluid causes the
arm to rotate. Holes in the spray arm spray the fluid into the
washer. The effectiveness of cleaning, however, is reduced because
the sprays emitted tend to fight against each other, reducing the
power of the sprays and varying their direction. Some of the energy
of the spray is utilized in rotating the spray arm, reducing the
water pressure efficiency of the spray. It is also difficult to
ensure coverage of the entire load with a rotating spray arm.
Further, the soil washed from the load tends to be pushed toward
the center of the washer, collecting on parts of the load, rather
than dripping off the load and into the sump.
[0005] In another cleaning system, a tube supplies cleaning-fluid
to two spray bars or arms, movably mounted on either side of the
washing chamber. The bars move simultaneously up the side of the
washer, spraying fluid from nozzles as they travel. The sprays
provide coverage of the entire washer, and increase cleaning
efficiency through the effect of fluid dripping through the load.
The system generally includes a complicated movement mechanism. A
safety clutch is therefore provided to reduce the danger to workers
in the event that the mechanism fails to operate properly. The
sprays from the two spray bars tend to fight against each other. In
a similar cleaning system, spray arms travel horizontally, rather
than vertically. In addition to having some of the problems
associated with the vertical cleaning system, the sprays tend to
push the soil into the center of the load, resulting in less
efficient cleaning.
[0006] There remains a need for a cleaning system with a reduced
cycle time that strips the biological matter from the load and
sanitizes the load more effectively.
[0007] Effective cleaning of the load is also achieved by
maintaining the concentration of a selected detergent in the
cleaning fluid. Because of the often high cost of the detergent,
and the large quantities of cleaning fluid employed, it is
desirable to maintain the detergent concentration close to the
minimum level required to insure effective cleaning. Traditionally,
the cleaning fluids are pumped in solution from storage tanks.
Periodically, the fluid in the tank is replenished by the separate
addition of detergent, in concentrated form, and water.
[0008] Measuring the actual concentration of the detergent in the
tank is time consuming, therefore methods have developed which
determine the concentration indirectly. Typically, one of two
methods is used to estimate the concentration of detergent. In the
first method, the addition of detergent to the tank from a
detergent supply container is timed. The concentration of detergent
is inferred from the operating time of a pump used to transfer the
detergent. This provides a simple means of determining detergent
concentration. However, if there is little or no detergent passing
through the pump, which could occur, for example, if the pump is
not working properly, then inaccurate measurements of detergent
concentrations are obtained. Inadequate cleaning and sanitization
of the process load results when the detergent concentration drops
below a minimum level.
[0009] In the second method, the detergent concentration is
inferred from a measure of the pH or conductivity of the cleaning
solution. This correlates well with the detergent concentration in
the fresh cleaning fluid. It is usual, however, to recycle a
portion of the cleaning fluid from the washer into the tank for
reuse. The recycled cleaning fluid contains soil from the load
which influences the pH and conductivity of the cleaning fluid.
Thus, the measure of pH or conductivity gives an inaccurate
determination of the concentration of detergent in the tank, the
inaccuracy becoming more pronounced at higher soil concentrations.
There remains a need for a cleaning system that insures effective
cleaning by providing a more accurate method of monitoring the rate
of addition of detergent.
[0010] The cleaning fluid is generally retained in the sump. The
cleaning fluid is pumped from the sump by a sump pump and
circulated to the nozzles in the washing chamber. The fluid level
in the sump must remain deep enough that the sump pump does not
cavitate. Conventionally, cage and rack washers employ sumps of
around 30-40 cm deep to supply the necessary depth of fluid for
operation of a typical sump pump. To provide this depth, a large
well is usually constructed through the floor beneath the washer,
with suitable reinforcement for the washer. Constructing such a
well within a concrete floor is frequently expensive and time
consuming. In some floor structures, there is insufficient below
ground depth available for the sump and the load is raised well
above floor level to enter the washer. Ramps provide a means of
raising the load, but as cages and hospital and scientific
equipment are frequently heavy, it is difficult to push them up a
ramp that is too steep. Shallow ramps make loading the washer
easier but take up considerable space and are hazardous if wheeled
carts are left unattended and accelerate down the slope.
[0011] Typically, a portion of the cleaning fluid is returned to
the tanks for recycling after it has been used in the washer.
Generally, sump pumps do not begin to operate until a sufficient
head of fluid has collected in the sump. Thus, there is a delay
between cycles while a portion of the used cleaning solution is
discarded and replaced with fresh water and added detergent. In
addition, because of the different soils encountered, cleaning
systems typically include two or more cycles, each using a
different cleaning fluid. Separate tanks are used for each of the
cleaning fluids. To avoid mixing of the different fluids, the
contents of the sump are pumped to the tanks between cycles. There
is a considerable time lag between cycles as the pump completes the
removal of the collected fluid from the sump. Moreover, the pump
ceases to operate once the fluid drops below the cavitation level
and the remaining fluid is simply drained to the waste system.
Draining of the sump in this way takes considerable time, and also
increases operating costs through higher detergent use and costs of
treating the waste to meet environmental standards.
[0012] The fluid collecting in the sump is typically heated by a
steam coil, located in the sump, to maintain the temperature of the
fluid during cycles. Because of heat losses from the sump
compounded by the length of time spent by fluid in the sump,
considerable wastage of energy occurs. In addition, the fluid in
the sump is heated to a higher temperature than that employed in
the washer to compensate for cooling. The hot soil-contaminated
cleaning fluid and steam coil pose a danger to workers entering the
washer between cycles, if they should accidentally fall into the
sump. There exists a need for a cage washer that operates without a
deep sump and that allows rapid removal of the used cleaning fluids
from the sump. There also exists a need for a cleaning system which
minimizes heat losses from the cleaning fluid.
[0013] Because of the cost of detergents, it is beneficial to reuse
as much of the cleaning fluid as possible. Traditionally, a filter
system removes solid matter from the used cleaning fluid before the
fluid is returned to the fluid tank which filter becomes clogged
with the solid material. The solid material clogging the filter
reduces the wash pressure and efficiency of cleaning. Periodic
down-time for manual cleaning of the filter is, therefore,
encountered. This filter cleaning time limits the operating period
of the washer, reducing the number of loads processed in a given
time. There is a need for a filter system which operates
continuously, flushing the build up of solid material from the
filter without the need for frequent cleaning of the filter.
[0014] The present invention provides a new and improved washer
with an improved cleaning system which overcomes the above
referenced problems and others.
SUMMARY OF THE INVENTION
[0015] In accordance with one aspect of the present invention, a
washer is provided. The washer includes a washing chamber, with
spray nozzles disposed in the washing chamber for spraying a
cleaning fluid over a load to be cleaned. A sump at the bottom of
the washing chamber collects the cleaning fluid sprayed over the
load. A sump pump removes cleaning fluid from the sump. A high
pressure pump pumps cleaning fluid from a cleaning fluid reservoir
to the spray nozzles.
[0016] In accordance with another aspect of the present invention,
a washer is provided. Spray nozzles disposed within a washing
chamber spray a cleaning fluid into the chamber. A pump pumps
cleaning fluid to the spray nozzles from a cleaning fluid
reservoir. A vertical traveler includes first and second
counterbalanced spray arms, disposed adjacent opposite sides of the
washing chamber, the spray nozzles disposed on the spray arms. The
traveler also includes a mechanism which supports the spray arms
for vertical travel and a drive system which alternately raises and
lowers the spray arms, the first spray arm traveling in an opposite
vertical direction to the second spray arm.
[0017] In accordance with yet another aspect of the present
invention a washer is provided. Spray nozzles disposed in a washing
chamber spray a cleaning fluid over a load to be cleaned. A pump
which pumps cleaning fluid from a cleaning fluid reservoir to the
spray nozzles. A filtration device removes suspended material from
the cleaning fluid. The device includes a fluid inlet which
receives cleaning fluid and a first fluid outlet which directs
unfiltered cleaning fluid from the filtration device to a drain.
The device also includes a valve which selectively closes to
prevent cleaning fluid from exiting the filtration device through
the first fluid outlet. The device further includes a filtration
screen which filters suspended material from the cleaning fluid and
a second fluid outlet through which filtered cleaning fluid leaves
the device.
[0018] In accordance with another aspect of the present invention a
fluid injection system for insuring accurate delivery of a
preselected quantity of a fluid is provided. A peristaltic pump
delivers the fluid, the preselected quantity of fluid measured in
terms of a number of pulses of fluid delivered by the pump. A flow
meter indicates whether fluid is flowing through the pump, the flow
meter detecting a flow of fluid in the fluid injection system.
[0019] In accordance with another aspect of the present invention,
a method for cleaning large equipment is provided. The method
includes supplying spray nozzles with a cleaning fluid at a high
pressure and spraying the cleaning fluid from the spray nozzles
over a load of equipment. The method further includes collecting
sprayed cleaning fluid in a sump and draining the cleaning fluid
from the sump with a sump pump.
[0020] In accordance with another aspect of the present invention,
a cleaning system is provided. The system includes supplying spray
nozzles with a cleaning fluid and spraying the cleaning fluid from
the spray nozzles over a load to be cleaned. The method also
includes sequentially raising and lowering the spray nozzles with a
vertical traveler. The sequence includes raising a first set of the
spray nozzles at the same time as lowering a second set of the
spray nozzles. The sequence further includes lowering the first set
of the spray nozzles at the same time as raising the second set of
the spray nozzles.
[0021] In accordance with another aspect of the present invention,
a cleaning system is provided. The system includes supplying spray
nozzles with a cleaning fluid at a high pressure, spraying the
cleaning fluid from the spray nozzles over a load to be cleaned and
collecting sprayed cleaning fluid. The system also includes closing
a filtration valve connected to a first outlet on a filtration
device and passing the sprayed cleaning fluid into the filtration
device. The system further includes filtering suspended material
from the sprayed cleaning fluid and passing the filtered cleaning
fluid from the filtration device through a second outlet. Still
further, the method includes selectively opening the filtration
valve and allowing a portion of the sprayed fluid to pass through
the first outlet and through the open filtration valve to remove
suspended material trapped within the filtration device.
[0022] One advantage of the present invention is that the cycle
time for the washer is considerably reduced over conventional
systems.
[0023] Another advantage of the present invention is that it
enables optimal detergent concentrations to be maintained with
minimal detergent additions.
[0024] Yet another advantage of the present invention resides in
its effective cleaning, with lower volumes of cleaning fluid.
[0025] Still further advantages reside in the shallow depth of the
sump, simple installation, and the low volume of cleaning fluid
remaining therein between cycles.
[0026] Still further advantages of the present invention will
become apparent to those of ordinary skill in the art upon reading
and understanding the following detailed description of the
preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The invention may take form in various components and
arrangements of components, and in various steps and arrangements
of steps. The drawings are only for purposes of illustrating a
preferred embodiment and are not to be construed as limiting the
invention.
[0028] FIG. 1 is a schematic of a preferred embodiment of a
cleaning system for a washer according to the present
invention.
[0029] FIG. 2 illustrates an expanded, perspective illustration of
the vertical traveler of FIG. 1;
[0030] FIG. 3 is a schematic of a detergent supply system in
accordance with the present invention;
[0031] FIG. 4 is an expanded side view of the vertical filtration
device of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] With reference to FIG. 1, a load to be cleaned is wheeled
into a washer 1, which includes a washing chamber 10, and washer
doors (not shown) are closed. A source of cleaning fluid, such as a
cleaning fluid reservoir or tank 12, supplies cleaning fluid to a
pump, preferably a high pressure pump 14, through a fluid line 16.
Optionally, plurality of tanks 12A, 12B and 12C each carry a
different cleaning or rinse solution. Valves 18A, 18B and 18C are
connected to cleaning fluid tanks 12A, 12B and 12C, respectively,
for selectively delivering cleaning fluid to the fluid line 16. The
high pressure pump 14 pumps the cleaning fluid at a pressure of
between 5 and 15 bar, preferably around 7 to 9 bar, to spray
nozzles 20 in the washer chamber.
[0033] With continuing reference to FIG. 1 and further reference to
FIG. 2, a vertical spray traveler 22 supports spray arms or bars
24, disposed inside the washing chamber 10, each spray arm carrying
a number of the spray nozzles 20. The high pressure pump 14
supplies the spray nozzles with cleaning fluid. An in-line
temperature booster or heater 26 raises the temperature of the
cleaning fluid to a preselected washing temperature before the
fluid reaches the spray nozzles. The spray nozzles spray the
cleaning fluid over the load to be cleaned. Depending on the nature
of the load to be cleaned, several wash cycles are employed. A
typical cleaning process includes a pre-wash, first detergent wash,
mid-rinse, second detergent wash and final rinses. The load is then
dried in the conventional manner.
[0034] A shallow sump 30 is located beneath the washing chamber 10
and collects the used fluid as it drips down from the washing
chamber. A sump pump 32, preferably a self-priming pump, sits in
the sump. The sump pump directs the used cleaning fluid to a
vertical filtration device, or filter 34 and the tanks 12 or to a
drain 36. Depending on the level of soil in the used fluid, the
fluid is either reused or disposed of. If the fluid is to be
reused, used fluid from the vertical filtration device is directed
to the fluid tank. If the fluid is to be disposed, the fluid is
directed to the drain. Fluid directed to the drain flushes solids
from the vertical filtration device.
[0035] Preferably, before disposal, the fluid passes through a cool
down vessel 40 where the temperature and pH of the fluid are
adjusted to meet environmental standards. Preferably, a pH probe 42
monitors the pH of the used fluid in the vessel. The pH of the
fluid is adjusted to the regulatory standard by the addition of
acid or alkali, as required.
[0036] With continuing reference to FIG. 1 and further reference to
FIG. 3, a detergent flow metering system 50 periodically supplies
fresh concentrated cleaning fluid to the tanks 12 to maintain
cleaning fluid levels. A water inlet 52 supplies water to tanks 12
to dilute the incoming concentrated fluid. Preferably the water
entering through inlet 52 is hot water. This raises the overall
temperature of the cleaning fluid in the tanks and allows the
in-line heater 26 to bring the temperature of the cleaning fluid
rapidly up to the required wash temperature.
[0037] The lower pressure sump pump 32 and the higher pressure pump
14 provide both a high pressure wash and also allow for the sump 30
to be small. The high pressure pump provides high pressure cleaning
fluid to the nozzles 20, relieving the sump pump of the task of
pressurizing the fluid in the system. In the preferred embodiment,
the sump pump transfers fluid from the sump to the tanks 12 or to
the drain 36. A small sump pump is adequate for this task. The
depth of the sump is reduced by using a self priming sump pump 32
which operates at the low fluid levels. A sump 30 of around 10-12
cm provides an adequate fluid depth for the self priming pump.
[0038] A washing system with a shallow sump offers a number of
advantages over conventional systems. First, construction costs are
reduced because the size of the area to be excavated is much
smaller, and the extent of support is much less. Alternatively, the
pit can be eliminated altogether by constructing the sump above
ground. Long, shallow ramps (not shown) between floor level and the
floor level of the washing chamber 10 readily allow heavy loads to
be wheeled into and out of the washing chamber 10.
[0039] Further advantages of the shallow sump 30 arise because
cleaning fluid does not accumulate in the sump. The sump pump 32 is
designed to operate at low fluid levels and, in the preferred
embodiment, operates fairly continuously to remove fluid as it
drains into the sump from the washing chamber 10. This reduces the
cycle time of the washer 1 because there is little fluid in the
sump to be removed between cycles. A cycle time of around 15
minutes is preferably achieved. In addition, because it operates at
lower fluid levels than a conventional washer sump pump, the sump
pump is able to remove virtually all the fluid in the sump. This
reduces the amount of cleaning fluid which is wasted, cutting the
costs of detergent, water and environmental compliance in operating
the washer.
[0040] Preferably the sump 30 has a sloping floor 54 which further
reduces the quantity of fluid in the sump.
[0041] The shallow sump 30 and in-line temperature booster 26
cooperate to provide further advantages of the washer. Conventional
washers which use a steam coil located within the sump, have high
heat losses. In the preferred embodiment of the present invention,
the shallow sump does not hold fluid for long periods. The sump
pump 32 rapidly returns the cleaning fluid to the cleaning fluid
tanks 12, which are preferably insulated to reduce heat loss, or
directs the fluid to the drain 36. Thus, heat loss from the sump is
minimized. This allows the steam coil to be eliminated. The in-line
temperature booster heats the fluid more efficiently than would a
sump steam coil by heating the cleaning fluid just prior to its
entry into the washing chamber 10.
[0042] The high pressure pump 14 and vertical traveler 22 combine
to provide an efficient system of cleaning cages and racks and
other scientific and healthcare equipment by reducing the length of
the cleaning cycle and reducing the volume of cleaning fluid
circulating through the washing chamber 10 in the cycle. The high
pressure pump, preferably constructed of a high grade stainless
steel, supplies cleaning fluid at a pressure at least three to five
times higher than in conventional cage cleaning systems. A pressure
of around 7-9 bar at the nozzles (around 9-10 bar at the pump) is
readily achieved in the preferred embodiment. Fluid at this
pressure removes soil from the load to be cleaned more effectively
than in conventional washers, thereby reducing the length of the
cleaning cycle. The range of the spray from each of the nozzles 20
is also increased, improving the cleaning efficacy of less
accessible portions of the load.
[0043] Varying the shape and number of the nozzles 20 on each spray
arm 24 also influences the impact of the spray. In the preferred
embodiment, 32 V-shaped nozzles provide good impingement and
cleaning efficiency, although it is envisaged that the number and
shape of the nozzles could be adjusted, dependent on the nature of
the load and the pumping equipment used.
[0044] In the preferred embodiment, the flow rate is reduced to
around 250 l/min, as compared with 740 l/min in a conventional
system. Even at the reduced flow rate, the wash impingement is
considerably higher than in conventional systems, because of the
higher pressures used. Approximately 200% higher impingement is
generated, at a distance of 30 cm from the nozzles, for the
combination of flow rate, pressure, and nozzle dimensions recited.
A reduced flow rate allows for smaller equipment. Tubes, valves and
pumps are all smaller than in conventional high flow systems. The
reduced flow rate also cuts operating costs in terms of energy use
by pumps and heaters, detergent quantities, water consumption and
fluid disposal.
[0045] With particular reference to FIG. 2, the alternating
vertical traveler 22 includes two counterbalanced spray arms 24,
24' one disposed on either side of the washing chamber 10. Like
parts associated with the two spray arms are similarly followed by
a prime ('). The spray arms move up and down in opposite
directions; as the first spray arm 24 moves downward, the second
spray arm 24' moves upward. Nozzles 20, optionally holes formed in
the spray arms, spray cleaning solution generally toward the center
of the washing chamber. Thus, as the first spray arm is spraying
the portion of the load closest to the top of the washing chamber,
the second spray arm is simultaneously spraying the bottom of the
load, close to the floor level. Cleaning fluid also flows down from
the top of the load and additional nozzles (not shown) on the top
of the washing chamber, aiding in the cleaning of lower portions,
which typically include the heaviest soiled areas of cages. As the
spray arms move toward the mid point of their travel, the sprays of
cleaning fluid cross. For all but the crossing point, the spray
arms spray independently, impinging on separate portions of the
load. The load is first sprayed from one side and then the other.
Therefore, the efficiency of the spray system is maximized and
thorough cleaning of the entire load is achieved rapidly.
[0046] The traveler 22 preferably includes a drive system 60 for
vertical countercyclical movement of the spray arms 24 and 24', and
a mechanism 62 for supporting the spray arms 24 in such a way that
the travel of each spray arm is limited to vertical movement in a
plane approximately parallel to sides of the washing chamber 10. It
is to be understood, however, that the invention is not limited to
the drive system and mechanism described herein, but that other
means conventionally known in the art for alternatively raising and
lowering the two spray arms are also contemplated.
[0047] The mechanism 62 preferably includes a pair of followers 64
and 64' each of which holds one of the spray arms 24 so that it
extends approximately horizontally on either side. Specifically,
the two followers are slidably mounted in a pair of vertical tracks
or rods 66 and 66' with the spray arms situated toward the center
of the washing chamber 10.
[0048] Spray arms 24 include hose attachments 68. Flexible U-shaped
hoses (not shown), connect to the hose attachments to supply
cleaning fluid. The U-shaped hoses are fed from supply line 16. The
spray arms and mechanism 62 are preferably constructed of materials
that withstand the chemical cleaning environment and
high-temperature drying commonly used.
[0049] In the preferred embodiment, the drive system 60 includes a
drive cable or belt 70 connected with both followers 64. A drive
means 72, such as a rodless pneumatic cylinder or alternating chain
and sprocket system, engages the drive cable. The drive means is
preferably housed outside the washing chamber 10, or is isolated
from the sprays of cleaning fluid, so that it is not subject to
damage by the cleaning fluids used in the washer 1.
[0050] The drive cable 70 forms a closed loop which passes from the
drive means 72 to the first follower 64 and then to the second
follower 64' before returning to the drive means. A guide system,
such as a series of pulley wheels 74, positions the drive cable 62
so that the drive cable does not interfere with the operation of
the spray arms 24 or the load to be processed. The drive means 72
draws the drive cable 70 a preselected distance in one direction
then allows the drive cable to return, or draws the drive cable,
the same distance in the reverse direction. In this way, the spray
arms are moved simultaneously, one traveling upward, while the
other travels downward. Because the spray arms and followers are
counterbalanced, there is little tension on the drive means 72. The
life expectancy of the drive means is much longer than in a
conventional spray system. In addition, it is easier to detect jams
and obstructions in the washing chamber 10 than for a conventional
system because any impediment to movement of the spray arms is
detected by the drive system and the movement of the spray arms is
arrested. Alternatively, a break away system 75 releases the cable
from the mechanism 62 or from the drive means. As an additional
safety precaution, the mechanism is sized and configured so as to
be easily grasped by an operator within the washing chamber without
damage to the operators hand. By pulling on one of the spray arms,
the movement of the drive cable 70 is arrested. This safety feature
eliminates the need for a safety clutch, as commonly used in moving
mechanical spray systems. Optionally, the speed of the drive means
is variable, causing the spray arms to travel up and down at a
preselected rate.
[0051] Preferably, a security cable 76 links the followers 64 and
64'. The security cable protects workers operating inside the
washing chamber 10 by preventing the followers and attached spray
arms 24 from falling in the event of a malfunction of the drive
system 60. As an additional safety feature, a safety cover 78
covers at least part of the drive cable 70 to protect workers from
injury by the cable.
[0052] With reference to FIGS. 1 and 3, the detergent injection
system 50 regulates the amount of detergent or other cleaning or
rinsing fluid introduced to the cleaning fluid tanks 12, insuring
that the preselected amount has been added. In a typical cycle, the
cleaning fluid is replenished at intervals by discarding a certain
portion of the cleaning fluid that has circulated through the
washing chamber 10, and refilling the cleaning fluid tank with
fresh detergent. The proportion of the cleaning fluid to be
discarded is determined by evaluations of the level of soil on the
load to be processed. Typically, for lightly soiled loads, such as
rodent cages, about 10% of the cleaning fluid is discarded after
each load, while for heavily soiled loads, such as primate cages, a
much larger proportion is discarded, up to 100%, typically, for the
most heavily soiled loads. After a preselected number of cleaning
cycles, the contents of the tanks 12 are completely drained and
refilled with fresh cleaning fluid. In this way, effective cleaning
of the process load is obtained, and detergent costs are
minimized.
[0053] The detergent injection system 50 includes flow meter 80 and
a metering pump, such as a peristaltic pump 82, for each cleaning
fluid tank 12. A supply of detergent, such as supply containers 84,
supplies detergent, or other selected cleaning fluids, to the
cleaning fluid tanks for replenishing the tanks. The peristaltic
pump pumps the detergent from the supply container to the cleaning
fluid tank. In the embodiment shown in FIG. 3, three supply
containers, 84A, B and C, contain an alkaline detergent, a rinse
aid, and an acid detergent, respectively. The three supply
containers supply corresponding cleaning fluid tanks 12A, B and C,
respectively, although it is envisaged that combinations of
detergent could be supplied to a single tank.
[0054] Detergent is metered into the cleaning fluid tank 12 by
peristaltic pump 82. As the peristaltic pump rotates it delivers
predetermined volume pulses of detergent into the cleaning fluid
tank. The amount of detergent added is proportional to the number
of these detergent pulses. Although a peristaltic pump 82 is the
preferred means of delivering detergent, alternatively, a
conventional pump supplies detergent to the tank, the detergent
addition measured in terms of the operating time of the pump.
[0055] Where the detergent is added to the tank 12 in concentrated
form, water is also added to the tank through inlet line 52 to
dilute the detergent to the desired concentration within the tank.
A series of valves 86A, B and C optionally allow for the separate
addition to tanks 12A, B, and C respectively.
[0056] With continuing reference to FIGS. 1 and 3 and further
reference to FIG. 4 a control circuit 88 optionally regulates the
amount of detergent and the volume of water added to the tank 12 to
replenish the cleaning fluid. A water flow meter 90 detects the
volume of water entering the tank. The control circuit monitors the
volume of water and addresses a look-up table 92. The look-up table
determines the amount of detergent to be added. The control circuit
signals the peristaltic pump 82 to deliver a corresponding number
of detergent pulses. The amount to be added is dependent on such
factors as the type of washing cycle, the type and concentration of
the detergent, the level of soil on the load, and the proportion of
cleaning fluid reused.
[0057] The flow meter 80 acts as a check on the injection system 50
by indicating whether fluid is flowing into the tank 12. This
insures that the detergent is being delivered to the tank 12. In
the event that the detergent in the container 84 is consumed, or
blockages occur in the system, the flow meter 80 registers this as
a decrease in the measured flow or an absence of flow. Optionally
the flowmeter 80 is linked to an alarm system 94 which alerts the
operator to the insufficiency in the detergent flow.
[0058] Optionally, the alkaline and acid detergents in the supply
containers 84A and C are used to balance the pH of the waste fluid
in the cool-down vessel 40. Cool down supply lines 96A and B carry
the detergent to the cool-down vessel 40. Acid and alkaline
neutralizer pumps 98A and 98B, respectively, control the flow of
detergent to the cool-down vessel 40.
[0059] With reference to FIGS. 1 and 5, the self cleaning filter or
vertical filtration device 34 filters used cleaning fluid for
reuse. The filter 34 reduces down-time of the washer by periodic
self cleaning of the filter during portions of the cleaning cycle
when the filter is not being employed for filtering the used
cleaning fluid collected in the sump 30. In a typical cleaning
cycle, the sump pump 32 delivers the used fluid to the self
cleaning filter through a used fluid line 100. The used fluid is
recycled by passing the fluid through the filter 34 and returning
the filtered cleaning fluid to the tank 12. To maintain cleaning
efficiency, however, a portion of the used fluid is discarded, to
be replaced by fresh cleaning fluid. The fluid to be discarded is
used to clean the filter of suspended material such as soil and
dirt that collects in the filter during filtration of the cleaning
fluid. A filtration valve 102 selectively opens to direct fluid
from the filter 34 through a spent fluid line 104 to the drain 36.
The filter 34 is cleaned automatically by the portion of the used
cleaning fluid that is directed through the filter to the drain
36.
[0060] The filter 34 includes a filtration chamber 106 and a
filtration screen 108, disposed within the filtration chamber. The
filtration chamber includes a fluid inlet 110, a lower or first
fluid outlet 112, and second, or side fluid outlet 114. The
filtration screen 108 preferably defines a cylinder. First and
second annular gaskets, such as upper gasket 116 and lower gasket
118, respectively, seal the cylindrical screen 108 at its open ends
around upper inlet 110 and lower outlet 112. The filtration screen
thereby surrounds a central region 120 of the filtration
chamber.
[0061] Used cleaning fluid enters the central region 120 of the
filtration chamber 106 through upper inlet 110. When the filtration
valve 102 is closed, the cleaning fluid passes through the screen
108. The screen preferably comprises a mesh, such as a stainless
steel mesh, the mesh size selected to trap soil and other suspended
particles within the central region, while not unduly limiting the
flow rate of the cleaning fluid through the filter 34. The filtered
used cleaning fluid exits the filtration chamber 106 through side
outlet 114. A recycled fluid line 122 is connected to the side
outlet. The recycled fluid line returns the filtered cleaning fluid
to the cleaning fluid tank 12.
[0062] When the filtration valve 102 is open, the majority of the
cleaning fluid passes straight through the central region 120 of
the filtration chamber 106. As it does so, it collects soil and
other dirt trapped by the screen 108, leaving the screen and
central region free of accumulated soil and other particulates and
ready to filter subsequent additions of cleaning fluid when the
filtration valve is again closed.
[0063] Cleaning the filter 34 in this way reduces operating costs
by using waste cleaning fluid rather than fresh water to remove
accumulated particles from the filter. Further, by cleaning the
filter during the cycle, considerable time is saved because the
operation of the washer 1 is not halted to allow for separate
cleaning.
[0064] The invention has been described with reference to the
preferred embodiment. Obviously, modifications and alterations will
occur to others upon reading and understanding the preceding
detailed description. It is intended that the invention be
construed as including all such modifications and alterations
insofar as they come within the scope of the appended claims or the
equivalents thereof.
* * * * *