Note: Descriptions are shown in the official language in which they were submitted.
2166597
WATER TRUCg WIT~ EX~AUST GAS PRESSURIZATION SYSTEM
Backaround of the Invention
1. Field of the Invention
The present invention relates to a pressurization system for
pressurizing a liquid holding tank on a truck such as a water truck
of the type generally used to clean and/or keep road surfaces damp
to minimize dust in construction operations and the like. Such
trucks can also be used as a source of water under pressure for
fire fighting, etc. More particularly, the present invention
relates to such a truck with a chassis mounted water tank which is
pressurized via the engine exhaust of the truck.
2. DescriPtion of the Related Art
Trucks which carry water tanks for spraying water on road
surfaces and the like are well known. Many such trucks simply
employ a bottom mounted discharge with a gravity feed system for
emptying the tanks. However, in order for the water to be used for
cleaning road surfaces, fighting fires, or simply pumping water to
a higher elevation, such water trucks must employ a pressurization
system for the water tank.
Heretofore, many water trucks employed discharge systems with
positive-displacement pumps fluidically communicating with their
water tanks for discharging the contents thereof under pressure.
Such a water discharge pump can be driven by a respective vehicle
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engine through a power take-off (PTO) unit. Alternatively, a
"pony" motor, comprising a suitable internal combustion engine, can
be mounted on the vehicle for operating the water pump or pumps
independently of the vehicle's engine.
A significant problem with previous water trucks relates to
problems associated with freezing of the water contents. Positive
displacement pumps, such as those used with previous water trucks,
may be particularly susceptible to damage caused by the freezing of
water left therein. Such freeze-damage to a water pump can cause
downtime for the water truck and necessitate the repair or
replacement of the damaged water pump at considerable expense,
particularly since these types of pumps can be relatively expensive
and/or time consuming to repair or replace. Moreover, if delays
are encountered in obtaining a replacement pump or parts therefor,
the downtime for the water truck can substantially increase.
Protecting previous water trucks from freeze damage often
involved blowing out their water systems with pressurized air,
draining thèir contents with appropriate petcocks, etc. Previous
~ water trucks with pumps driven by PTO's and pony motors thus tended
to be relatively complex and required time-consuming winterization
procedures for protection when subjected to temperatures below
freezing. Another disadvantage with a PTO-driven pump is that its
output is dependent upon the speed of the vehicle engine. The
optimum engine speed for a PTO-driven pump can be at or near idle,
but operating the vehicle over various road conditions in different
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gears can cause wide fluctuations in pump output with resulting
uneven water distribution.
Still further, PTO drive systems and pony engines can add
considerably to both the initial cost and the ongoing maintenance
~ expenses associated with a water truck. Such previous trucks and
their water distribution systems also tended to have a number of
moving parts, which were susceptible to damage and wear from
freezing and other causes.
It is therefore preferable to provide a water distribution
system wherein the water tank is pressurized as needed with
relatively few moving parts and with a relatively simple freeze
protection system. Moreover, it is preferable to provide a water
distribution system which can operate at engine idle speed yet
provide reliable pressurization for attaining operating pressures
of up to 35 ~SI, and to provide such a system which can accommodate
various water application procedures such as dust control, fire
fighting, etc.
Heretofore there has not been available a water truck with a
pressurized discharge system having the advantages and features of
the present invention.
Sllmm~ry of the Invention
The present invention is directed to a pressurization system
for a tank on a water truck. The pressurization system includes a
pipe connected at one end via a three-way valve directly into the
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engine exhaust system of the truck and at the other end into a top
portion of the water tank. Engine exhaust is thus selectively
introduced into the water tank to pressurize the tank. With the
inventive system, pressures within the tank of 35 PSI or greater
are readily achievable, and the tank can be pressurized even with
the engine running at idle speed. The three-way valve is remotely
controllable from the truck cab so that engine exhaust can be
selectively by-passed from the tank to a muffler and/or other
standard exhaust components.
The tank includes a top-mounted fill opening with a hinged cap
and an internal, counter-weighted flapper valve. Once the hinged
cap is opened, the truck can be driven beneath a high volume water
source and water from the source, when it hits the counter-weighted
flapper valve, opens the valve by urging the flapper against the
action of the counter-weight. Once the flow of fill water is
stopped, the flapper is once again closed by action of the counter-
weight, all without requiring the driver to leave the truck cab. A
pressure limiting valve is through-fitted through the top of the
tank and an anti-siphon orifice in a water outlet conduit serves to
prevent water from freezing in the outlet conduit once
pressurization is stopped.
Obiects and Advanta~es of the Invention
Objects and advantages of the present invention include:
providing an improved pressurization system for a tank on a water
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truck; providing such a pressurization system which uses engine
exhaust gas from the truck engine to pressurize the tank; to
provide such a system in which a three-way valve controllable from
the truck cab allows exhaust gas to be selectively introduced into
the tank, or, alternatively, to be diverted to a standard exhaust
system; to provide such a system in which the tank has an improved
top-mounted fill flapper valve; to provide such a system ln which
- the tank has an anti-siphon feature to prevent water from being
siphoned into and possibly freezing in an liquid outlet pipe; to
provide such a system with a spray boom for spreading water evenly
across a road surface and with front-mounted sprayers which are
directed towards a roadside curb for washing the curb; to provide
such a system which can be used for either road cleaning and dust
prevention, or alternatively, for fire fighting or other relatively
high pressure water applications; to provide such a system with
relatively few moving parts; to provide such a system which does
not require a positive displacement pump; to provide such a system
with a relatively simple, effective and efficient arrangement for
protection against damage from water freezing therein; to provide
such a system which does not require either a power take-off from
the vehicle engine or a pony motor; and to provide such a system
which is reliable and inexpensive, capable of operation even when
the truck engine is at idle speed, and which is particularly well
adapted for its intended purpose.
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Other objects and advantages of this invention will become
apparent from the following description taken in conjunction with
the accompanying drawings wherein are set forth, by way of
illustration and example, certain embodiments of this invention.
The drawings constitute a part of this specification and
include exemplary embodiments of the present invention and
illustrate various objects and features thereof.
Brief Descri~tion of the Drawin~s
Fig. 1 is a side elevational view of the water truck with
potions of the tank sidewall broken away to illustrate the interior
thereof, the pressure relief valve and gas inlet, and portions of
the cab broken away to illustrate the valve control and engine.
Fig. 2 is a rear elevational view of the water truck with rear
spray bar end sections in a spray position in solid lines and in an
up, travel position in dotted lines.
Fig. 3 is a greatly enlarged, fragmentary view of a portion of
the exhaust pipe and tail pipe with a three way valve partially
broken away to illustrate the interior thereof.
Fig. 4 is a greatly enlarged, fragmentary view of a liquid
fill inlet on the tank with a hinged cap shown open in solid lines
and closed in dotted lines, and with a counter-weighted flapper
valve shown closed in solid lines and open in dotted lines.
166597
Detailed Descri~tion of the Preferred Embodiments
I. Introduction and Environment
As required, detailed embodiments of the present invention are
disclosed herein; however, it is to be understood that the
disclosed embodiments are merely exemplary of the invention, which
may be embodied in various forms. Therefore, specific structural
and functional details disclosed herein are not to be interpreted
as limiting, but merely as a basis for the claims and as a
representative basis for teaching one skilled in the art to
variously employ the present invention in virtually any
appropriately detailed structure.
Certain terminology will be used in the following description
for convenience in reference only and will not be limiting. For
example, the words "up", "down", "right" and "left" will refer to
directions in the drawings to which reference is made. The words
"inward" and "outwardl' will refer to directions toward and away
from, respectively, the geometric center of the embodiment being
described and designated parts thereof. Said terminology will
include the words specifically mentioned, derivatives thereof and
words of a similar import.
Referring to the drawings in more detail, a water truck with
an exhaust gas pressurization system is generally designated by the
reference numeral 10, and generally comprises a truck 12 with a
tank 14 mounted on the truck 12.
2166;~9 ~
II. Truck 12
The truck 12 includes a chassis 20 mounting a cab 22 and the
tank 14, front and rear ends 21, 23, and an internal combustion
engine 24.
An exhaust pipe 26 extends from the engine 24 generally below
the tank 14 and terminates at a tailpipe 28.
III. Tank 14
The tank 14 includes a first or front end 30, a second or rear
end 32 and a sidewall 34 which collectively form a generally
cylindrical configuration. A pressurized gas inlet opening 36 is
formed in an upper portion of the sidewall 34 in proximity to the
front end 30.
A pressurized gas outlet opening 42 with an adjustable
pressure relief valve 43 and adjustment screw 44 and a liquid
outlet opening 45 are formed in the upper portion of the tank
sidewall 34 in spaced relation from a liquid inlet opening 111 and
with the liquid outlet opening 45 positioned in proximity to the
tank rear end 32.
- 20
IV. Pressurization SYstem
A diverter valve 48 with the general configuration of a T-
valve having an inlet 50, a pressure outlet 52 and an exhaust
outlet 54 is serially interposed in the exhaust pipe 26 in fluidic
connection therewith, with the inlet 50 leading to the engine 24
21665g7
and the exhaust outlet 54 leading to the tail pipe 28. The
diverter valve 48 includes a valve member or flap 56 movable
between a first or pressure position communicating the inlet 50
with the pressure outlet 52 (solid lines in Fig. 3) and a second or
exhaust position communicating the inlet 50 and the exhaust outlet
(broken lines in Fig. 3), as well as a plurality of intermediate
positions dividing portions of the exhaust gas stream between the
pressure and exhaust outlets 52 and 54 respectively. A diverter
valve control cable 57 iS mechanically connected to the valve
member or flap 56 and extends to a knob 58 located in the cab 22
for operation of the diverter valve 48 by an operator or driver
from within the cab 22.
The pressure outlet 52 leads to a pressure pipe 60 which is
braced to the cab 22 via a support bracket 61 and which extends
through the pressure inlet opening 36 and into the tank 14 with an
open end 62 extending into the tank. When the flap 56 is in the
pressure position, exhaust gas is directed through the pipe 60 and
into the tank 14, which contains a volume of liquid 63, usually
water. Exhaust gas from the engine 24 iS thus introduced, under
20 pressure from the engine pistons, into a gas pocket 64 above the
level of the liquid 63. The exhaust gas thus pressurizes the tank
14, with available pressure levels from 5 to 35 PSI, depending upon
the level of liquid 63 in the tank, the speed of the engine 24 and
the position of the flap 56.
2166597
Referring to Figs. 1 and 2, a liquid outlet pipe 71 extends
through the liquid outlet opening 45 in the top of the tank 14, the
pipe 71 having a first, open end 72 which reaches to a level
proximate the bottom of the tank 14. An orifice 73 extends through
the side of the pipe 71 inside of but near the top of the tank 14.
The orifice 73 performs an anti-siphon function to prevent water
from being siphoned into the pipe 71 in a position to freeze during
cold weather. The pipe 71 has a second end 74 which enters a T
fitting 75. A fire hose attachment 81 leads from one side of the
fitting 75 and a spray bar supply pipe 82 leads from the bottom of
the fitting 75. A standard water tap 83 is connected to the spray
bar supply pipe 82 above a shut-off valve 84 in the pipe 82. The
shut-off valve 84 controls the flow of liquid to a spray bar center
portion 85. An additional supply pipe 86 extends from the spray
bar supply pipe 82 forward to a pair of front mounted spray slots
87, each with it's own valve 88 (Fig. 1). The spray slots 87 are
directed toward the side of the truck 12, for washing curbs or the
like.
The spray bar center portion 85 has a plurality of spray heads
91 positioned along the bottom thereof. The center portion 85
terminates in a pair of hinges 92 with each hinge 92 fluidically
connecting the center portion 85 with one of a pair of spray bar
end portions 93. The end portions 93 are thus pivotable between a
down, spray position (shown in solid lines in Fig. 2) and an up or
travel position (shown in dotted lines in Fig. 2). Each spray bar
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_.
end portion 93 also includes a plurality of spray heads 91
extending along the bottom thereof. A fill tube 94 extends through
a fill opening 95 in the tank 14, with a first, open end 101
extending downward into the tank 14 and a second end 102 with a
threaded coupling 103 extending out of and downward from the tank
14 such that the tank 14 can be filled from a low-lying water
source such as a fire hydrant or the like.
Referring to Fig. 4, a fill opening sleeve 104 extends through
the top portion of the tank 14 with a hinged cap 105 pivotally
attached thereto for covering an opening 111 in the sleeve 104.
The cap 105 is shown in an open position in solid lines and in a
closed position in dotted lines. The sleeve 104 is larger than a
standard fill inlet, preferably being 18 inches or more in
diameter. Pivotally attached to the bottom of the sleeve 104 via a
hinge 112, and covering the bottom of the opening 111, is a flapper
valve 113. A counter-weight 114 is connected to the flapper valve
113 and extends outward from the hinge 112. The counter-weight 114
is heavy enough to counter the weight of the flapper cover 113 and
normally urges the cover upward to a sealing engagement with the
sleeve 104 (as shown in solid lines in Fig. 4).
In order for a driver to fill the tank 14 from an elevated
water source, such as a water tower (not shown), the truck 12 is
driven beneath the water source to a position at which a supply
outlet 115 is suspended above the top of the sleeve 104 and over
the opening 111. The driver then simply starts the flow of water
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through the supply outlet by pulling a cord or the like and the
weight of water from the supply outlet 115 urges the flapper valve
113 downward, thus allowing water to enter the tank 14. Once the
flow of water is cut off, the flapper valve 113 automatically
pivots upward due to the action of the counterweight 114, thus
sealing off the opening 111 and allowing the tank 14 to be
pressurized. With the inventive counter-weighted flapper valve
113, a driver can fill the pressurized tank 14 from an elevated
water source without having to climb on top of the tank 14 to open
the cover 105, which can be locked to a normally open position, and
even without leaving the cab 22.
It is to be understood that while certain forms of the present
invention have been illustrated and described herein, it is not to
be limited to the specific forms or arrangement of parts described
and shown.
