U.S. patent application number 13/708974 was filed with the patent office on 2013-04-18 for mobile fluid distribution system and method.
This patent application is currently assigned to CATERPILLAR INC.. The applicant listed for this patent is CATERPILLAR INC.. Invention is credited to Peter W. Anderton, Ronald Brown, Gary A. Ellertson, David C. Orr.
Application Number | 20130092749 13/708974 |
Document ID | / |
Family ID | 43219120 |
Filed Date | 2013-04-18 |
United States Patent
Application |
20130092749 |
Kind Code |
A1 |
Anderton; Peter W. ; et
al. |
April 18, 2013 |
MOBILE FLUID DISTRIBUTION SYSTEM AND METHOD
Abstract
A fluid distribution system and method for mobile applications.
The system includes a power source, a pump driven by the power
source, and a motor driven by the pump. The system also includes a
spray head with a fluid inlet passage, a fluid outlet passage, a
fluid piston disposed in a chamber for controlled access between
the inlet and outlet passages and defining a variable orifice, and
a hydraulic cylinder controllably engaged to the orifice. The fluid
piston and the hydraulic cylinder are aligned with a common
longitudinal axis, and the inlet passage is offset from the axis in
a direction opposed to the location of the outlet passage.
Inventors: |
Anderton; Peter W.; (Peoria,
IL) ; Brown; Ronald; (Morton, IL) ; Orr; David
C.; (Marco Island, FL) ; Ellertson; Gary A.;
(Pleasant Prairie, WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CATERPILLAR INC.; |
Peoria |
IL |
US |
|
|
Assignee: |
CATERPILLAR INC.
Peoria
IL
|
Family ID: |
43219120 |
Appl. No.: |
13/708974 |
Filed: |
December 8, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12472415 |
May 27, 2009 |
8376244 |
|
|
13708974 |
|
|
|
|
Current U.S.
Class: |
239/11 |
Current CPC
Class: |
E01H 10/007 20130101;
B05B 13/005 20130101; E01H 3/02 20130101 |
Class at
Publication: |
239/11 |
International
Class: |
B05B 13/00 20060101
B05B013/00 |
Claims
1-8. (canceled)
9. A method for distributing a fluid, the method comprising the
steps of: determining a ground speed of a mobile machine configured
for fluid distribution; determining a pressure of fluid being
delivered to a spray head having a variable orifice; comparing the
determined pressure to a desired fluid pressure; controlling a
variable displacement motor to maintain the desired fluid pressure
based on the comparison; and controlling a size of the variable
orifice during operation as a function of the ground speed and
independent of fluid pressure to vary a flow rate of fluid output
from the spray head to maintain a desired distribution of
fluid.
10. (canceled)
11. A method, as set forth in claim 9, wherein controlling the size
of the variable orifice includes the step of controlling sizes of a
plurality of orifices on a corresponding plurality of spray
heads.
12. A method, as set forth in claim 11, wherein controlling sizes
of a plurality of orifices includes the step of controlling the
sizes of the plurality of orifices independent of each other.
13. A method, as set forth in claim 9, further including the steps
of: determining a condition associated with a location for fluid
distribution; determining a desired fluid pressure as a function of
the condition; controlling the variable displacement motor to
maintain the desired fluid pressure; and controlling the variable
orifice as a function of the ground speed and as a further function
of the determined condition to maintain the desired distribution of
fluid.
14. A method, as set forth in claim 13, wherein determining a
condition includes the step of determining a level of dryness
associated with the location.
15-20. (canceled)
21. A method, as set forth in claim 9, further including the step
of controlling a pump to adjust a pressure of fluid being delivered
to the spray head.
22. A method, as set forth in claim 9, wherein controlling a size
of the variable orifice includes the step of controlling movement
of a fluid piston of the spray head.
23. A method, as set forth in claim 9, further including the step
of controlling a fluid distribution pattern.
24. A method, as set forth in claim 23, wherein the fluid
distribution pattern is laminar flow.
25. A method, as set forth in claim 9, wherein the desired
distribution of fluid is a desired distribution per unit of
area.
26. A method, as set forth in claim 11, wherein controlling sizes
of the plurality of orifices includes the step of controlling
movement of a fluid piston of each of the corresponding plurality
of spray heads.
27. A method, as set forth in claim 11, further including the step
of controlling a fluid distribution pattern.
28. A method, as set forth in claim 27, wherein the fluid
distribution pattern is laminar flow.
29. A method, as set forth in claim 11, wherein the desired
distribution of fluid is a desired distribution per unit of
area.
30. A method, as set forth in claim 9, wherein an operator may
select a spray mode.
31. A method, as set forth in claim 9, wherein determining a
pressure of fluid being delivered to a pray head includes the step
of determining a pressure of fluid at multiple locations.
32. A method, as set forth in claim 9, wherein the operation
includes fluid distribution.
33. A method, as set forth in claim 11, wherein the operation
includes fluid distribution.
34. A method, as set forth in claim 9, wherein the variable orifice
is continuously variable.
35. A method, as set forth in claim 11, wherein the plurality of
orifices are continuously variable.
Description
TECHNICAL FIELD
[0001] This disclosure relates generally to a system and method for
fluid distribution and, more particularly, to a system and method
for controlled distribution of a fluid in a mobile environment.
BACKGROUND
[0002] Fluid distribution systems, in particular mobile fluid
distribution systems, are used in a variety of applications. For
example, at mining and construction sites, it is common to use
mobile fluid distribution systems to spray water over routes and
work areas to minimize the creation of dust during operations. A
specific example might include a water truck that sprays water over
roads at a mine site.
[0003] Other applications of mobile fluid distribution systems may
include spraying of pesticides and herbicides, e.g., for
agricultural use, disbursement of saline solutions on roads for
snow and ice control, fire suppression, and the like.
[0004] For various reasons, such as cost and consistent fluid
application, it is desired to maintain control of the amount and
pattern of fluids being distributed, in particular with regard to
maintaining a uniform and consistent application of fluid per unit
of area. For example, when spraying water on mine roads, it may be
desired to uniformly distribute the water over the road surface to
avoid applying excess water in specific locations.
[0005] Typical fluid distribution systems spray fluids at pressures
that are directly proportional to engine speeds of the mobile
machines. Operators attempt to keep fluid pressure, and the
resultant flow of fluids, relatively constant by maintaining
constant engine speeds, at least to the extent possible. These
efforts typically require operating mobile machines at reduced
transmission gear ratios to maintain desired engine speeds.
However, these efforts cannot be maintained, for example, when
ascending or descending steep inclines, conditions which generally
require changing engine speeds.
[0006] Efforts have been made to maintain fluid pressures in
proportion to machine speed, i.e., ground speed, rather than engine
speed. Although this has resulted in improved fluid distribution
per unit area, it is still difficult to maintain precise control
during various operating maneuvers, such as starting and stopping,
and as operating conditions vary. Furthermore, many of these
systems still distribute fluids in proportion to fluid pressure,
which adds to the difficulty of consistent application per unit of
area.
[0007] One example of an attempt to achieve uniform fluid
application is described in U.S. Pat. No. 5,964,410 to Brown et al.
(the Brown patent). Brown employs spray heads with variable
orifices to attempt maintenance of constant velocities and exit
flow trajectories. The spray heads are pressure controlled,
however, relying on pressure of the fluid being sprayed to overcome
a spring force to open the spray nozzle. Furthermore, the
components that are used to control the nozzle are located in the
main fluid flow chamber, and thus are susceptible to corrosion and
contamination by particles and debris in the fluid. As a result,
the system would still have difficulty achieving consistent
application of the fluid per unit of area during various operating
conditions.
[0008] The present disclosure is directed to overcoming one or more
of the problems as set forth above.
SUMMARY
[0009] In one aspect of the present disclosure a fluid distribution
system is disclosed. The system includes a power source, a pump
driven by the power source, and a motor driven by the pump. The
system also includes a spray head with a fluid inlet passage, a
fluid outlet passage, a fluid piston disposed in a chamber for
controlled access between the inlet and outlet passages and
defining a variable orifice, and a hydraulic cylinder controllably
engaged to the orifice. The fluid piston and the hydraulic cylinder
are aligned with a common longitudinal axis, and the inlet passage
is offset from the axis in a direction opposed to the location of
the outlet passage.
[0010] In another aspect of the present disclosure a method for
distributing a fluid is disclosed. The method includes determining
a ground speed of a mobile machine, determining a pressure of fluid
being delivered to a spray head having a variable orifice,
comparing the determined pressure to a desired fluid pressure,
controlling a motor to maintain the desired fluid pressure, and
controlling the variable orifice as a function of the ground speed
and independent of fluid pressure to maintain a desired
distribution of fluid.
[0011] In yet another aspect of the present disclosure a spray head
for a fluid distribution system is disclosed. The spray head
includes a fluid inlet passage, a fluid outlet passage, a fluid
piston disposed in a chamber for controlled access between the
inlet and outlet passages and defining a variable orifice, and a
hydraulic cylinder controllably engaged to the orifice. The fluid
piston and the hydraulic cylinder are aligned with a common
longitudinal axis, and the inlet passage is offset from the axis in
a direction opposed to the location of the outlet passage.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a diagrammatic illustration of a mobile machine
suited for use with the present disclosure;
[0013] FIGS. 2A and 2B are diagrammatic views of a spray head
suited for use with the present disclosure;
[0014] FIG. 3 is a cut-away view of the spray head of FIGS. 2A and
2B;
[0015] FIG. 4 is a representative block diagram of a fluid
distribution system;
[0016] FIGS. 5A and 5B are representative diagrams of a hydraulic
system suited for use with the fluid distribution system of FIG.
4;
[0017] FIG. 6 is a flow diagram depicting a method of the present
disclosure;
[0018] FIG. 7 is a flow diagram depicting another method of the
present disclosure; and
[0019] FIG. 8 is a diagrammatic representation of an operator
control suited for use with the present disclosure.
DETAILED DESCRIPTION
[0020] Referring to the drawings, a mobile fluid distribution
system 100 and method for distributing fluids is shown.
[0021] Referring to FIG. 1 in particular, a mobile machine 102
suited for use for distributing fluids is depicted. The mobile
machine 102 of FIG. 1 is shown as a truck, i.e., typical for use in
off-highway applications, converted for use to distribute fluids.
However, other types of mobile machines may be employed, for
example, articulated trucks, on-highway trucks, tractor-scrapers,
tractors in combination with trailers, and the like.
[0022] Although not labeled as such in FIG. 1, the mobile machine
102 is fitted with a fluid tank (element 430 in FIG. 4), and is
shown with a variety of piping, hoses, pumps and valves for fluid
distribution purposes. In particular, the mobile machine 102 in
FIG. 1 is shown as an off-highway truck configured as a water truck
for spraying water at a work site that typically generates much
dust during work operations. The present disclosure, however, may
also apply to other types of mobile machines set up to distribute
water or other types of fluids in a wide variety of applications.
For example, a tractor pulling a trailer may be used to distribute
chemicals in agricultural settings, an on-highway truck may be
configured to spray a saline solution on roads, runways, or parking
lots to melt snow and ice, and other varieties of applications and
setups may be used.
[0023] FIGS. 2A and 2B illustrate views of a spray head 200 that
may be used with the present disclosure. As shown more clearly and
in more detail in FIG. 3, the spray head 200 may be assembled in
relation to a longitudinal axis 312 for reference purposes. For
example, the spray head 200 includes a fluid inlet passage 302 and
a fluid outlet passage 304. The outlet passage 304 may be located
at a position offset from the longitudinal axis 312. The inlet
passage 302 may be located at a position offset from the
longitudinal axis 312 and in a direction opposed to the location of
the outlet passage 304. The location of the inlet passage 302
relative to the location of the outlet passage 304, i.e., on
opposite sides of the longitudinal axis 312, may contribute to
providing a laminar flow of fluid from the spray head 200. Such
laminar flow may result in a flat spray pattern having droplets of
a minimal size large enough to achieve reduced atomization of the
fluid. In a water truck example, this may contribute to optimal
fluid control from the spray head 200 to a desired surface during
mobile spraying.
[0024] A fluid piston 306 disposed in a chamber 307 of the spray
head 200 defines a variable orifice 308 and may provide controlled
access between the inlet passage 302 and the outlet passage 304.
Controllably engaged to the orifice 308 is a hydraulic cylinder
310. More specifically, the hydraulic cylinder 310 includes a
hydraulic piston 316 connected to a rod 322, which in turn is
connected to the fluid piston 306. In operation, as the hydraulic
piston 316 is controlled to move, i.e., linear with the
longitudinal axis 312, the rod 322 moves and the fluid piston 306
subsequently moves, which results in a change in size of the
orifice 308.
[0025] In the embodiment shown in FIG. 3, the hydraulic cylinder
310 is a double acting hydraulic cylinder 310. That is, the
hydraulic cylinder 310 is hydraulically controlled to move in
either direction. In more detail, the hydraulic piston 316 includes
a head end 318 and a rod end 320. The hydraulic cylinder 310
includes a first hydraulic port 324 positioned to allow hydraulic
fluid in the hydraulic cylinder 310 at the rod end 320, and a
second hydraulic port 326 positioned to allow hydraulic fluid in
the hydraulic cylinder 310 at the head end 318. Detailed operation
of hydraulic circuits that may be used to control the spray heads
200 is described below.
[0026] The hydraulic cylinder 310 may include a spring 328 disposed
in the head end 318. The spring 328 may provide additional force to
hold the orifice 308 in a closed position, for example when the
hydraulic circuits are shut down. The spring 328 may also be used
to supplement the force applied to the head end 318 of the
hydraulic cylinder 310. For example, the spring 328 may be selected
having a desired compression rate (e.g., force per unit of
compression). The total forces applied to the head end 318 may be
from a combination of hydraulic fluid supplied to the second
hydraulic port 326 and the force of the spring 328, and the total
forces applied to the rod end 320 may be from a combination of
hydraulic fluid supplied to the first hydraulic port 324 and
pressure from fluid entering the inlet passage 302. If the fluid
pressure entering the inlet passage 302 is kept fairly constant,
then control of the degree of opening of the orifice 308 may be
attained by varying the hydraulic fluid to the first hydraulic port
324.
[0027] It is noted that the spray head 200 may be configured for
control of the fluid piston 306 by use of other configurations. For
example, the hydraulic cylinder 310 may be configured without the
second hydraulic port 326 and the associated hydraulic components,
thus relying on hydraulic pressure on the rod end 320 and spring
pressure on the head end 318.
[0028] It is further noted that the spray head 200 may be
configured for control by other than a hydraulic piston 316. For
example, the hydraulic cylinder 310, hydraulic piston, 316, and all
associated hydraulic circuits and components could be replaced by
electrical or mechanical actuators. As specific examples, the fluid
piston 306 may be controlled by an electrical actuator such as a
solenoid (not shown), or may be controlled by a mechanical actuator
which may include any of a variety of cams, screws, levers,
fulcrums, and the like (also not shown).
[0029] The hydraulic cylinder 310 may be fluidically isolated from
the chamber 307, thus isolating the fluid that passes through the
orifice 308 from the hydraulic fluid in the hydraulic cylinder 310.
This design offers the advantage of keeping particles and
contaminants away from the components in the hydraulic cylinder
310, for example when water from retaining ponds is used for dust
suppression applications.
[0030] The spray head 200 may include one or more fluid deflectors
314 connected to the spray head 200 and configured to control a
fluid distribution pattern from the outlet passage 304. For
example, two fluid deflectors 314 are shown in FIG. 3 (and may be
viewed in FIGS. 2A and 2B, although not labeled as such). The fluid
deflectors 314 may be configured to control the fluid distribution
pattern, for example in a laminar flow, from the outlet passage 304
in furtherance of the laminar flow control that may be provided by
the above-described specific locations of the inlet and outlet
passages 302,304 relative to the longitudinal axis 312.
[0031] A seal plate 330, attached to the fluid piston 306, may be
used to further deflect fluid to attain a desired spray pattern,
for example by designing the seal plate 330 with a desired shape
and physical configuration.
[0032] Referring to FIG. 4, a block diagram of a representative
portion of a fluid distribution system 100 is shown. For exemplary
purposes, FIG. 4 is described as applied to a mobile machine 102,
i.e., an off-highway truck, set up for use as a water truck at a
mining or construction site, although the fluid distribution system
100 shown in FIG. 4 could be used in other applications as noted
above.
[0033] A power source 402 to supply power for the fluid
distribution system 100 may also be used to supply motive power for
the mobile machine 102. For example, the power source 402 may
include a prime mover 404 for the mobile machine 102. The prime
mover 404 may include an engine 406 drivingly connected to the
mobile machine 102 and a transmission 408 driven by the engine 406.
The engine 406 and transmission 408 may be chosen from among many
types and configurations that are well known in the art. It is also
well known to use the power supplied by prime movers 404 for other
purposes in addition to providing motive power. For example, an
off-highway truck, prior to being configured for water distribution
applications, may have been designed to use power from the prime
mover 404 for applications such as raising and lowering a truck
bed.
[0034] A pump 410, driven by the power source 402, is in turn
configured to drive a motor 412. The pump 410 may be driven by the
engine 406 or the transmission 408 by means that are known in the
art, and may be a hydraulic pump 410 as is also known in the art.
The pump 410 may be configured to drive the motor 412 by well known
hydraulic means. A hydraulic tank 428 may be used to supply and
recover hydraulic fluid to and from the pump 410 and motor 412.
[0035] In the embodiment shown in FIG. 4, the pump 410 may be a
fixed displacement type and the motor 412 may be variable
displacement. For example, an off-highway truck configured for use
as a water truck may have an existing fixed displacement pump 410
already in place for other purposes. Adding a variable displacement
motor 412 may offer advantages in control of the fluid distribution
system 100, for example by enabling control of fluid pressure to
maintain the fluid at a constant desired pressure regardless of
engine speed or ground speed. A fixed displacement pump 410 may
still be used for applications other than fluid distribution
without being affected by changes in fluid distribution parameters.
For example, the pump 410 may drive the motor 412 and also drive a
system for cooling brake components (not shown). The brake cooling
system would not be affected by load changes from the fluid
distribution system 100. In alternative embodiments, the pump 410
and motor 412 may be other combinations of fixed and variable
displacement devices, for example a variable displacement pump and
a fixed displacement motor.
[0036] The motor 412 is fluidly connected to one or more spray
heads 200, e.g., three spray heads as shown in FIG. 4. More
specifically, the motor 412 may provide hydraulic power to a fluid
pump 426, which in turn delivers fluid by way of fluid lines 432 to
the inlet passages 302 and through the orifices 308 of the spray
heads 200. The fluid pump may obtain fluid from a fluid tank 430,
for example a water tank mounted on a water truck.
[0037] Although the three spray heads 200 in FIG. 4 are shown
connected by common fluid lines 432 to the fluid pump 426, each
spray head 200 may be independently controllable. In addition, each
spray head 200 may include an orifice 308 that is continuously
variable from a fully closed position to a fully open position, as
distinguished from an orifice that is capable of only being open or
closed.
[0038] A ground speed sensor 414, located on the mobile machine
102, may be configured to sense a ground speed as the machine
moves. The ground speed sensor 414 may be located to sense ground
speed based on operation of the transmission 408, rotational
movement of a ground engaging member (not shown) such as a wheel,
or by some other method known in the art.
[0039] A fluid pressure sensor 416 may be located to sense pressure
of fluid in fluid lines 432, or alternatively fluid pressure
exiting fluid pump 426.
[0040] An engine speed sensor 418 may be located to sense the speed
of the engine 406.
[0041] A transmission state sensor 420 may be located to sense the
state, e.g., forward, neutral, or reverse, of the transmission 408.
The transmission state sensor 420 may alternatively sense direction
of motion of the mobile machine 102 to determine transmission
state.
[0042] Any of the above sensors may be configured to directly sense
a desired parameter, may sense one or more secondary parameters and
derive a value for the desired parameter, or may determine a value
for the desired parameter by some other indirect means. Operation
of the above sensors for their intended purposes are well known in
the art and will not be described further.
[0043] A controller 422 may receive sensed or derived signals from
the ground speed sensor 414, the fluid pressure sensor 416, the
engine speed sensor 418, and the transmission state sensor 420. The
controller 422 may also be controllably connected to one or more of
the motor 412 and the spray heads 200. For example, and as
described in more detail below, the controller 422 may use
information received from the ground speed sensor 414 and the fluid
pressure sensor 416 to determine a desired fluid pressure to
maintain, and responsively control the variable displacement of the
motor 412 to maintain a constant fluid pressure. The controller 422
may also use information received from the engine speed sensor 418
for further control of the variable displacement motor 412. The
controller 422 may also use the above received information to
control the variable orifices 308 of the spray heads 200 to control
a flow rate of the fluid being delivered to and sprayed from the
spray heads 200. In one specific example, the controller 422 may
determine from the transmission state sensor 420 if the mobile
machine 102 is moving in reverse, and responsively shut off the
fluid distribution system 100 during this condition.
[0044] An operator control device 424, located in a cab compartment
(not shown) of the mobile machine 102, may provide an operator with
a variety of control and display functions for the fluid
distribution system 100. The operator control 424 may be of any
desired configuration and may be custom designed for specific
mobile machines and applications.
[0045] Referring to FIG. 8, the operator control 424 may include a
display 802. The display 802 may be used to provide visual
indication of a wide variety of information including, but not
limited to, a current operating mode of the fluid distribution
system 100, various sensed and determined parameters (such as
engine and ground speeds, fluid pressures, and the like) fluid
levels in the fluid tank 430, and any other information desired to
be provided. The display 802 may include visual display of
information and may also include audible alerts such as low levels
of fluid in the fluid tank 430, and the like.
[0046] Various operating modes may be selected from the operator
control 424 through the use of a wide variety of operator input
devices (not shown) which may include, but are not limited to,
switches, dials, levers, joysticks, buttons, and the like. FIG. 8
lists a sampling of available modes in no particular order. The
list is not meant to be all-inclusive and additional modes may be
made available as desired.
[0047] Pre-programmed spray modes may allow an operator to select
from among a variety of spray modes based on the intended
application. It may also be a feature that additional modes may be
programmed for later use.
[0048] Manual mode may allow an operator to set up desired
parameters, for example selecting a desired pressure, flow rate,
number of active spray heads, spray pattern, and the like.
[0049] Intermittent mode may allow an operator to select a pulsing
spray pattern that may be adjusted as a function of time or spray
distance.
[0050] Fire fighting mode may allow the fluid to be diverted to a
spray cannon (not shown), hose reel (not shown), and/or to any
combination of spray heads 200.
[0051] Tank fill mode may enable pumps and valves needed to pump
fluid into the fluid tank 430. Tank fill mode may be set up to be
automatic, semi-automatic, or manual. Alternatively to pumping
fluid into the fluid tank 430, tank fill mode may provide for
filling of the fluid tank 430 by gravity or external pumping
means.
[0052] Cleanout mode may be used to open each orifice 308 to a
maximum open position to flush debris from the spray heads 200.
This feature may be particularly useful, for example, when a water
truck obtains water from a pond or stream, thus introducing
sediment, debris and particles into the fluid tank 430.
[0053] Oncoming traffic cutout mode may be used to quickly and
easily shut off specific spray heads 200 that otherwise would
undesirably direct spray onto objects, such as other vehicles
passing the mobile machine 102. This feature may be needed for a
short duration only, and thus may be controlled by use of a
momentary contact switch or trigger.
[0054] Referring to FIGS. 5A and 5B, various embodiments of a
hydraulic system 500 suited to control a portion of the fluid
distribution system 100 is shown. The hydraulic system 500 is
representative only and is not meant to be limiting in scope and
application. For illustrative purposes only, four spray heads 200
are shown.
[0055] Each hydraulic cylinder 310 may be double acting, i.e., each
hydraulic piston 316 is controlled at both a head end 318 and a rod
end 320. A head end valve 502, hydraulically connected to the
second hydraulic port 326, is controlled to apply pressure to the
head end 318, thus driving the orifice 308 toward a closed
position. A rod end valve 504, hydraulically connected to the first
hydraulic port 324, is controlled to apply pressure to the rod end
320, thus driving the orifice 308 toward an open position.
[0056] FIG. 5A depicts one head end valve 502 controlling all spray
heads 200 simultaneously, and one rod end valve 504 controlling
each spray head 200 individually. In this configuration, the single
head end valve 502 applies pressure to all spray heads 200 toward a
closed position, and each rod end valve 504 is independently
controlled to apply pressure to a corresponding spray head 200
toward an open position. Other configurations may be used, however,
without deviating from the scope of the present disclosure. For
example, as depicted in FIG. 5B, multiple head end valves 502 may
be used to control a corresponding number of spray heads 200
individually.
[0057] A hydraulic supply 506 and a hydraulic tank 508 supply
hydraulic fluid to and from the head end and rod end valves
502,504. Although the hydraulic supply 506 and hydraulic tank 508
are shown as separate units for each valve (for ease of
illustration), it is contemplated that one hydraulic supply 506
provides pressurized hydraulic fluid to all of the valves 502,504,
and one hydraulic tank 508 provides a return to tank path for all
of the valves 502,504. The hydraulic supply 506 may be a dedicated
supply, e.g., a pilot supply, located on the mobile machine 102, or
may be part of a larger hydraulic system which may include the pump
410. In like manner, the hydraulic tank 508 may be a separate tank
or may be associated with the hydraulic tank 428.
INDUSTRIAL APPLICABILITY
[0058] An example of application of the present disclosure can be
described with reference to the flow diagrams of FIGS. 6 and 7.
[0059] Referring to FIG. 6, in a first control block 602, a ground
speed of the mobile machine 102 is determined. The ground speed may
be sensed directly, for example by a ground speed sensor 414, or
may be determined by other means known in the art.
[0060] In a second control block 604, a fluid pressure of the fluid
lines 432 is determined. The fluid pressure may be sensed directly,
for example by a fluid pressure sensor 416, or may be determined by
other means known in the art. The fluid pressure may be determined
from the fluid lines 432 directly, or may be determined at some
other location associated with the fluid lines 432, such as the
spray head 200, the fluid pump 426, the pump 410, the motor 412, or
some other location. The fluid pressure may also be determined at
multiple locations.
[0061] In a third control block 606, the determined fluid pressure
is compared to a desired fluid pressure. The desired fluid pressure
may be set based on a pre-programmed spray mode, a manually input
desired fluid pressure, by some other operating mode of the fluid
distribution system 100, or by some other determined or input
parameter.
[0062] In a fourth control block 608, the motor 412 is controlled
to maintain the determined fluid pressure at the desired fluid
pressure. The motor 412 may be a variable displacement motor 412,
which may be controlled by varying the displacement of the motor
412, as is well known in the art. Alternatively, the pump 410 may
be a variable displacement pump 410 that may be controlled for the
same purpose. Other types of controllable pumps and motors, such as
electric and such, may also be used to control the fluid pressure.
As an alternative to controllable pumps and/or motors, other means
known in the art, such as variable orifices, valves, and the like,
may be used to maintain the fluid pressure as well.
[0063] In a fifth control block 610, each variable orifice 308 is
controlled to maintain a desired distribution of fluid. In a fluid
distribution system 100 having multiple spray heads 200, and thus a
corresponding multiple of orifices 308, each variable orifice 308
may be controlled independent of each other variable orifice 308,
and all orifices 308 may be controlled independent of fluid
pressure. The variable orifices 308 may be controlled to maintain a
desired fluid distribution, for example a desired fluid
distribution per unit of area. Control of the variable orifices 308
may be accomplished by controllably opening and closing each
orifice in a manner described above with reference to FIG. 3.
Opening and closing an orifice 308 is a variable process, thus
providing a continuously variable number of orifice positions for
optimal control of the distribution of fluid.
[0064] Referring to FIG. 7, a flow chart depicting another method
of the present disclosure is shown.
[0065] In a first control block 702, a condition associated with a
location for fluid distribution is determined. Although a number of
conditions may be determined, for illustrative purposes an
exemplary condition of a level of dryness associated with the
location is described. The level of dryness may be determined, for
example in a water truck application, by an operator's observations
of a relative dryness of the roads and surfaces to be sprayed.
Alternatively, other more automated means for determining a level
of dryness may be used.
[0066] In a second control block 704, a desired fluid pressure as a
function of the determined condition is determined. The desired
fluid pressure may be a modification of the desired fluid pressure
associated with the method described with reference to FIG. 6.
[0067] In a third control block 706, the motor 412 is controlled to
maintain the desired fluid pressure, in the same manner as
described above with reference to FIG. 6.
[0068] In a fourth control block 708, the variable orifice 308 is
controlled as a function of both the ground speed and the
determined condition to maintain the desired distribution of
fluid.
[0069] The present disclosure provides a mobile fluid distribution
system 100 and method which offers many advantages, among which
includes providing control of fluid distribution over a desired
area, in particular control of an amount of fluid distributed over
a desired unit of area under varying conditions. Maintaining a
constant fluid pressure while varying the flow rate through
individual spray heads 200 provides more precise control of fluid
distribution and the capability for a number of specialized flow
control modes.
[0070] Other aspects can be obtained from a study of the drawings,
the specification, and the appended claims.
* * * * *