Liquid pilot assembly

A liquid pilot assembly for use in an outdoor fuel spill fire fighting trainer is provided. This assembly includes a spark plug igniter unit, a liquid fuel system, an air distribution system, a housing enclosing the components and a vaporization subassembly disposed within the housing for changing liquid fuel to vapor fuel.

FIELD OF THE INVENTION 
The invention generally relates to a liquid pilot assembly and, in 
particular, the invention relates to a liquid pilot assembly which has a 
vaporizing subassembly for use in an outdoor fuel spill fire fighting 
trainer. 
BACKGROUND OF THE INVENTION 
The prior art aircraft fire fighting trainer is described in U.S. Pat. No. 
5,415,551 issued May 16, 1995. 
The prior art fire fighting trainer includes a mock-up aircraft or other 
equipment simulation, a liquid fuel distribution and burner system having 
a liquid fuel supply line, a burner control connected to the liquid fuel 
supply line, and a central control connected to the burner control. 
One problem with the prior art fire fighting trainer is that there is no 
easy method of igniting the liquid propane fuel. 
SUMMARY OF THE INVENTION 
According to the present invention, a pilot module assembly is provided 
which is a self-igniting, continuous flame device which is used to 
reliably ignite combustible fuel supplies. This assembly has an igniter 
unit to electronically light the pilot flame, a liquid fuel distribution 
system, an air distribution system, a housing and a vaporizer system which 
is disposed inside the housing. 
By using the vaporizer system, which is disposed inside the housing, the 
present invention eliminates the need for a separate vaporizer system, 
which has valves and regulators, which is disposed near to a supply tank 
and which has a supply network line to the igniter unit(s). Further, it 
can be submerged in water, with only the upper surface of the assembly 
exposed to view. 
One object of the invention is to provide a pilot module assembly for an 
aircraft fire fighting trainer for safe operation and control of the 
trainer. 
Another object of the invention is to provide a pilot module assembly which 
has an integral vaporizer. 
A further object of the invention is to provide a structure in a fire 
fighting trainer which simulates a liquid fuel spill fire outside a 
mock-up aircraft. 
Other objects and the advantages of the invention will occur to one skilled 
in the art from the following detailed description of the preferred 
embodiment of the invention as illustrated in the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 and 2, a liquid pilot assembly generally indicated at 
10 is provided. The assembly 10 includes a spark plug igniter unit 
generally indicted at 12, a liquid fuel supply system 14, an air 
distribution system 16, a housing generally indicated at 18 and a 
vaporization system or subassembly 20. 
The spark plug igniter unit 12 has an inclined pipe 22, which is supported 
by the housing 18, a cap 23 which is supported by the inclined pipe 22 and 
a spark plug 24 which is supported by the cap 23. The spark plug is 
preferably of the turbine engine type which does not have a spark gap. The 
spark plug 24 has a control circuit or remote control unit (not shown) so 
it can be controlled from any point. 
The fuel system 14 has an inlet line 26 and a lower outlet nozzle or nozzle 
portion 28 which is supported by the housing 18. 
The air system 16 has an inlet line 30, which is supported by the housing 
18 and has a vertical tube 32. The vertical tube 32 has an upper outlet 
nozzle 34, which is arranged to cause a circular air flow or air swirl in 
the system. 
The housing 18 has a cylindrical or peripheral shell or wall or plate 36, 
which forms a chamber 38. The shell 36 has a floor plate 40 welded 
thereto. The plate 40 is supported by four framing or leg angles 42. The 
angles 42 are supported by two bearing angles 44 which have respective 
anchor bolt holes 45. The housing 18 also has a cover or hood 46, which is 
bolted to four angle pieces or clip angles 48, that are respectively 
welded to the shell 36. The clip angles 48 have respective bolts 50 for 
holding the hood 46. The shell 36 has an axis 51. 
The vaporizer 20 has a plurality of gravel stones 52, which are disposed in 
the chamber 38 to a fixed gravel level 54. The vaporizer 20 also has a 
volume of water 56 which is disposed between stones 52 in the chamber 38 
to a variable water level 58. Water 56 may have a separate water supply 
line (not shown) and level control such as a float valve (not shown), as 
desired. 
Liquid propane enters the chamber 38 from the nozzle 28 and is vaporized by 
the thermal exchange of the gravel and the water 56 to cause propane vapor 
above the water level 58. 
The cylinder 36, and the gravel 52 at its level 54, and the hood 46 enclose 
a propane vapor ignition zone or space 60. The propane vapor in the zone 
60 is swirled about axis 51 by air from the air nozzle 34. The swirling 
air and propane vapor mixture is then ignited by sparks from the spark 
plug 24, forming a flame (not shown). The flame exits through annular 
pathway 62. The assembly 10 also has a fuel pit 64. The flame disperses 
through the fuel pit 64. The fuel pit 64 has pit water 66, which has a top 
level 68. The water level 68 may vary above or below the cylinder water 
level 58. 
In operation, the liquid pilot assembly 10 acts as a self-igniting 
continuous pilot flame device. The assembly 10 is used to reliably ignite 
combustible fuel supplies. The assembly consists of an igniter unit 12 to 
electronically light a pilot flame, the vaporizer 20 and the fuel 
distribution line 14 to dispense the pilot fuel, and an air distribution 
line 16 to provide combustion air. The components 12, 14, 16 are built as 
a modular assembly 10. The assembly 10 is designed for use in a fuel spill 
fire training simulator. The assembly 10 is positioned in the fuel spill 
pit 64, partially submerged in water, with only the upper surface of the 
assembly 10 exposed to view. 
The spark plug 24 creates a spark which directly ignites the pilot flame. 
An energy source (not shown) for the spark plug 24 is provided remotely by 
a separate module (not shown) and the spark itself is produced by the 
spark plug 24. Spark unit 12 has a turbine engine type spark plug. This 
type of spark plug has no gap between its electrodes, so there is 
virtually no chance that foreign materials will bridge an igniter gap and 
prevent operation. The igniter unit 12 is essentially self-cleaning due to 
the high energy of the spark produced. The spark unit 12 is mounted in the 
pilot housing 18 and is easily removed for component replacement or 
wiring. The spark plug 24 is positioned so water and extinguishing agents 
roll off the surface, thereby prolonging component life and improving 
reliability. 
The fuel distribution system 14 consists of a tube 26 and nozzle 28 which 
dispense fuel beneath the surface 58 of the water. This system 14 is 
connected to a controlled remote fuel source (not shown). 
The air distribution system 16 includes a nozzle 34 mounted above the 
surface 58 of the water. The air system 16 is connected to a regulated 
remote air source which supplies a constant flow of clean, compressed air. 
This air improves the combustion process and prevents the local air/fuel 
mixture from becoming too rich. 
The assembly 10 includes frame angles 42, 44 which mount to the base of the 
fuel spill pit. Chamber 38 is filled with stone. Chamber 38 contains the 
igniter spark unit 12, a fitting connected to an electrical conduit (not 
shown) and provisions for mounting the fuel distribution nozzle 28, air 
distribution nozzle 34 and a thermal sensor (not shown). The top of 
assembly 10 has a metal cover 46 which serves to shield the pilot flame 
from wind, rain, extinguishing agents, etc. The cover 46 also protects the 
parts 34, 28, 24 from physical damage. 
The liquid pilot assembly 10 is operated remotely by way of a computer (not 
shown) or electro-mechanical operator console (not shown). Upon pilot 
command, an electrical signal is sent to the spark plug 24, and a 
continuous spark is produced. At the same time, a fuel valve (not shown) 
is opened and liquid propane flows out of the fuel distribution nozzle 28. 
This fuel vaporizes and mixes with air and is subsequently ignited by the 
spark. A thermal sensor (not shown) is mounted near the top of the 
dispersion chamber 38 and is used to verify that the pilot flame is lit. 
Liquid pilot assembly 10 has the unique ability to reliably vaporize and 
ignite liquid propane within assembly 10, without the use of a 
conventional propane vaporizer and vapor distributor network. The liquid 
propane is released beneath the water and is vaporized as it travels 
through the water in the dispersion chamber 38 to the top of the assembly 
10. The vapor is then ignited by the spark generated by the igniter. The 
chamber 38 is filled with stones 52 to reduce water bubbling and splashing 
within the chamber 38 as the propane expands during vaporization. The 
compressed air aids the combustion process by mixing with the vaporized 
fuel and insuring a proper fuel air mixture. 
The addition of compressed air also makes this assembly 10 unique. The 
continuous flow of high pressure air keeps the burn area clear of debris 
and extinguishing agents. Extinguishing foams are particularly difficult 
to disperse from the pilot area around spark plug 24 due to their physical 
consistency. These foams form a thin film around the fuel as it escapes 
from the water and prevents the fuel from mixing with the surrounding air, 
which in turn prevents the pilot flame from igniting. The air from the air 
distribution nozzle 34 helps to clear the foam away from the local burn 
area and breaks any foam bubbles, thereby mixing air with the fuel. The 
air further helps to keep the tip of the spark plug 24 cool and dry, which 
improves overall assembly reliability. 
Some of the advantages of the assembly are indicated hereafter: 
A) Assembly 10 has the ability to vaporize and ignite a liquid propane fuel 
source. In a liquid propane fueled system, this eliminates the need for 
running a separate vapor line from the tank farm to each pilot area. This 
also eliminates all of the hardware (valves, regulators, vaporizers, etc.) 
associated with either drawing vapor off the top of the supply tank or 
vaporizing liquid propane pumped out of the bottom of the tank. 
B) Assembly 10 uses water 56 as a dispersion medium and helps insure that 
liquid propane is fully vaporized by the time it reaches the ignition 
source. The liquid propane travelling through the underwater piping will 
be heated by the water, beginning the vaporization process. Any propane 
still in liquid form at the time of discharge will be quickly vaporized as 
it travels to the surface. 
C) The liquid pilot assembly 10 is mounted in pit 64, partially submerged 
in pit water 66. This arrangement helps protect the components from 
damage. The water 56 prevents direct flame impingement on most of the 
components, and acts as a large heat sink to help cool the components 
above the surface of the water. 
D) Assembly 10 uses compressed air and thus helps keep the combustion area 
clear of debris. The continuous air supply keeps the burn area clear of 
debris and extinguishing agents. Extinguishing foams are particularly 
difficult to disperse from the pilot area due to their physical 
consistency. These foams form a thin film around the fuel as it escapes 
from the water and prevents the fuel from mixing with the surrounding air, 
which in turn prevents the pilot flame from lighting. The air from the air 
distribution nozzle 34 helps to clear the foam away from the local burn 
area and breaks any foam bubbles, thereby mixing air with the fuel. The 
air also helps keep the spark plug tip cool and dry, which improves 
reliability. 
E) Assembly 10 uses compressed air and thus aids the combustion process by 
mixing with the fuel and preventing an overly rich fuel condition. 
F) Assembly 10 has the ability to be used outdoors, relatively unaffected 
by weather conditions. The liquid pilot assembly 10 can withstand most 
outdoor environments. 
While the invention has been described in its preferred embodiment, it is 
to be understood that the words which have been used are words of 
description rather than limitation and that changes may be made within the 
purview of the appended claims without departing from the true scope and 
spirit of the invention in its broader aspects.