Device for preventing flareup in liquid fuel burners by regulating fuel flow from the removable fuel tank

A safety device for preventing uncontrolled burning in wick-fed liquid fuel burners of the type where a removable tank (60) feeds a fuel chamber (40), which supplies the fuel to a wick (54) via a sump opening in the upper surface of the chamber (40). A plate (32) in the removable tank (60) contains an orifice (34), which restricts fuel egress from the tank. A fill tube (44) traverses the plate. An inner equalization tube (24), a chamber (30), and an outer equalization tube (28) are connected to the fill tube (44).

CROSS-REFERENCE TO RELATED APPLICATIONS 
This invention is an improvement over the inventions of several earlier 
applications, to-wit: 
Ser. No. 08/130,290, filed Oct. 4, 1993, now U.S. Pat. No. 5,338,185, 
granted Aug. 16, 1994, in the names of Richard W. Henderson and George R. 
Lightsey; 
Ser. No. 08/247,925, filed May 23, 1994, now U.S. Pat. No. 5,456,595, 
granted Oct. 10, 1995, in the name of Richard W. Henderson; 
Ser. No. 08/297,048, filed Sep. 30, 1994, now U.S. Pat. No. 5,409,370, 
granted Apr. 25, 1995, in the name of Richard W. Henderson; 
Ser. No. 08/365,804, filed Dec. 29, 1994, now U.S. Pat. No. 5,549,470, 
granted Aug. 27, 1996, in the name of Richard W. Henderson; 
Ser. No. 08/514,583, filed Aug. 14, 1995, now U.S. Pat. No. 5,662,468, 
granted Sep. 2, 1997 in the name of Richard W. Henderson; 
Ser. No. 08/559,922, filed Nov. 17, 1995, now U.S. Pat. No. 5,551,865, 
granted Sep. 3, 1996, in the names of Richard W. Henderson and Samuel R. 
Henderson; 
Ser. No. 08/684,131, filed Jul. 19, 1996, now U.S. Pat. No. 5,730,115, 
granted Mar. 24, 1998, in the name of Richard W. Henderson; and 
Ser. No. 08/684,132 filed Jul. 19, 1996, now U.S. Pat. No. 5,772,425, 
granted Jun. 30, 1998 in the name of Richard W. Henderson. 
BACKGROUND 
1. Field of Invention 
This invention relates to safety devices, specifically to a mechanism for 
prevention of flareup in barometric-type wick-fed liquid fuel burners. 
2. Discussion of Prior Art 
Wick-fed liquid fuel burners, such as kerosene heaters, are used for space 
or area heating In cabins, mobile homes, and the like. In such burners 
liquid fuel from a fuel chamber is supplied to a wick which is exposed to 
the oxygen of the atmosphere. Once the wick has been ignited, flame 
intensity and heat generation are controlled by adjusting the length of 
the wick exposed within a wick-receiving combustion chamber. 
A common type of kerosene heater is the barometric style, in which gravity 
causes liquid fuel to be delivered to a horizontal fuel chamber from a 
vertically-oriented, removable tank inserted into a mating well, or sump, 
in a top surface of the fuel chamber. In some cases a sight gauge is 
mounted on the side of the removable tank to monitor the fuel level in 
that tank when the tank is filled, and during operation of the burner. The 
flow of fuel from the removable tank into the fuel chamber is governed by 
a barometric valve in the cap on the removable tank, which, in normal 
operation, maintains the level of the fuel in the fuel chamber at the 
level of the barometric valve. A partial vacuum above the fuel in the 
removable tank prevents the fuel from flowing into the fuel chamber until 
the fuel level in the fuel chamber drops below the barometric valve, which 
allows air to enter the removable tank. As air enters the removable tank 
through the barometric valve, fuel in the removable tank flows into the 
fuel chamber until its level in the fuel chamber rises and covers the 
barometric valve in the removable tank cap, causing fuel flow from the 
removable tank to cease. 
The barometric valve consists of a spring-loaded plunger, which has an 
enlarged head at one end. When the removable tank is inserted into the 
fuel chamber, the plunger head contacts a pin located in the fuel chamber, 
which pushes the plunger back, allowing the fuel in the removable tank to 
be in fluid communication with the fuel chamber. 
When the tank is removed, the action of the spring on the plunger head 
forces it against the opening in the tank cap, sealing the opening and 
preventing fuel from leaving the tank. The capacity of the removable tank 
is typically about four to five liters (four to five quarts), while the 
fuel chamber can hold a maximum of about two liters (two quarts). 
Various improvements have been made to such burners which make them safer 
to operate. For example, tip-over shut-off mechanisms, manual shut-off 
devices, and low-level O.sub.2 detectors have been employed. However, 
these burners continue to cause fires that result in death, injury, and 
property loss. These fires are caused, because, when high-volatility fuels 
are present in the burner, under certain conditions, vapors from the sump 
area can be ignited by the wick flame, and in other cases, fuel can 
overflow the fuel chamber. When the overflowing fuel ignites, the result 
is an uncontrolled fire, or flareup. 
The most common reason for fuel overflow is the inadvertent use of fuels 
with high vapor pressures. Examples of such fuels are gasoline, naphtha, 
and inferior kerosene, which has a low flash point. In a barometric 
heater, overflow of fuel from the fuel chamber can occur if the partial 
vacuum in the removable tank is lost. As the temperature of the heater and 
its surroundings increases, the vapor pressure of the fuel in the 
removable tank increases and, under certain conditions, allows fuel to 
escape from the removable tank at a rate greater than the rate of 
wick-controlled burning of the fuel. Should this process continue, the 
fuel chamber will overflow, since the removable tank holds about two to 
three liters (two to three quarts) more than the capacity of the fuel 
chamber. When the fuel chamber overflows, the fuel spills onto the top of 
the fuel chamber, and can then ignite, causing an uncontrolled fire. A 
second way that the partial vacuum in the barometric heater's removable 
tank can be lost is by air entering the removable tank due to compromise 
of its integrity. 
There are safety devices that drop the wick down, thereby extinguishing the 
flame, if the burner tips over or experiences excessive vibration, or if 
abnormal combustion is detected. Other safety devices detect high levels 
of CO.sub.2 and low levels of O.sub.2 in the vicinity of the heater, and 
use these to control burning rates. Still others regulate the position of 
the wick during the ignition and extinguishing operations of the heater to 
prevent excessive flaming during these operations. Examples are shown in 
U.S. Pat. Nos. 4,363,620, issued Dec. 14, 1982 to Nakamura; 4,872,831, 
issued Oct. 10, 1989 to Fujimoto; 4,797,088, issued Jan. 10, 1989 to 
Nakamura; and 5,165,883, issued Nov. 24, 1992 to Van Bemmel. However, not 
only do these devices fail to prevent flareup, they are ineffective in 
stopping flareup after its onset. In some cases, the safety devices 
require the use of electrical power and electronic circuitry for 
actuation: this increases the cost of the burners significantly, without 
rectifying the flareup problem. 
It has been suggested in two publications ("Kerosene Heater Fires: 
Barometric Type," R. Henderson et al., Fire Marshals Bulletin (National 
Fire Protection Association), Vol. 87-5, p. 8 (1987); "Barometric Kerosene 
Heaters," R. Henderson, Fire and Arson Investigator (International 
Association of Arson Investigators), Vol. 39, No. 3, p. 26 (1989)) to make 
the size of the removable tank of barometric kerosene heaters comparable 
in volume to that of the fuel chamber so that flooding of the fuel chamber 
will not occur. To implement this suggestion, either the capacity of the 
removable tank must be reduced, or alternatively, that of the fuel chamber 
must be increased. However, reducing the capacity of the removable tank 
will reduce the burn time accordingly, and possibly affect the 
marketability of the heaters. Increasing the capacity of the fuel chamber 
will require that new tanks be designed and implemented and could increase 
the size of the burner to an unacceptable level. 
Also, it has been suggested that a float device be introduced into the fuel 
chamber to be used to activate the automatic wick extinguishing mechanism, 
and a sight gauge be present to show dangerous fuel levels in the fuel 
chamber. Introduction of such a float device would also require that the 
fuel chamber be redesigned, as discussed above. Although some burners have 
sight gauges in the fuel chamber, the sight gauges are used only to 
indicate whether or not fuel is present, not when dangerous fuel levels 
are present in the fuel chamber. 
In addition it was proposed that a tank block-out device be installed. In 
this, a float in the fuel chamber pushes a pin that moves if the removable 
tank is withdrawn from the heater. Once again, such a device would require 
a redesigning of the fuel chamber and insertion of moving parts inside a 
somewhat restricted space. 
U.S. Pat. No. 5,080,578, issued Jan. 14, 1992 to Josephs, claims that its 
device controls flareup in wick-fed liquid fuel burners by a) cutting off 
the flow of fuel to the wick in response to excessive heat by blocking a 
fuel line, and b) withdrawing the wick into the wick chamber when sensing 
excessive heat. However, Josephs' device has several disadvantages: 
a) Excessive heat must be gene rated near the sensors before the flow of 
fuel is interrupted, or the wick is withdrawn. Therefore, since flareup is 
not prevented, the device only limits the spread of excessive flames after 
flareup has al ready occurred. 
b) Heat sensing devices must be near the area where uncontrolled burning is 
taking place due to overflow of fuel. But often the path that the 
overflowing fuel takes is random and flareup may not initially occur near 
the heat sensors. 
c) The device is not applicable to barometric liquid fuel burners--one of 
the most common wick-fed liquid fuel burners in use--because these burners 
do not have fuel lines. 
d) From the onset of flareup in wick-fed liquid fuel burners, fire is 
present outside the wick; therefore, retracting the wick does not affect 
the flareup process. 
The device of the above U.S. Pat. No. 5,338,185 of Henderson and Lightsey 
consists, in part, of an excess fuel containment compartment below the 
level of the fuel chamber. It prevents flareup by activating a 
wick-extinguishing mechanism when the presence of excess fuel is detected 
in the fuel chamber. While this device has much merit, to be effective it 
requires activation of a second mechanism, that is, an automatic wick 
extinguisher. Should that mechanism fail to respond, due to tar buildup on 
the wick or a mechanical problem, flareup may still occur in some 
situations. 
The device of the above U.S. Pat. No. 5,456,595 of Henderson prevents 
flareup by lifting the removable tank when excess fuel is present in the 
fuel chamber, thereby shutting off the barometric valve and stopping fuel 
flow from the removable tank. For this device to work, a spring must be 
provided to lift the removable tank and its contents (liquid fuel), the 
total weight of which can be up to some five kilograms (ten pounds). 
Accordingly, should the spring lose strength, or should the removable tank 
become hindered in its upward movements this device may not be able to 
prevent flareup in some situations. 
The device of the above U.S. Pat. No. 5,409,370 of Henderson prevents 
flareup by dropping the pin which holds open the barometric valve in the 
removable tank cap, thereby closing the valve and stopping fuel flow into 
the fuel chamber. Should the valve not close properly, this device may not 
prevent flareup in some situations. 
The device of the above U.S. Pat. No. 5,549,470 of Henderson prevents 
flareup by providing a thermal barrier between the combustion cylinder and 
the removable tank, which helps lower the temperature of the removable 
tank so that fuel vapor pressures do not become excessive. In addition, it 
includes a warning gauge that alerts the user to the dangerous condition 
of the burner when excess fuel is present in the fuel chamber. It also 
provides an excess fuel containment system that can hold the entire 
contents of the removable tank should all the fuel be released rapidly. 
This system consists, in part, of a fuel containment sump, which extends 
upward from the top of the fuel chamber, and which surrounds the removable 
tank, but which does not have a closure at its top. This device has much 
merit in that it is effective without involving any moving parts for its 
operation. However, the presence of the components of the device would add 
to the weight of the burner. 
The device of the above U.S. Pat. No. 5,662,468 prevents flareup by 
containing fumes in the vicinity of the removable tank and by providing 
(a) a closure at the top of the compartment housing the removable tank, 
and (b) a block-out mechanism for the removable tank should excess fuel be 
present in the fuel chamber. Although this device also has much merit, it 
requires the introduction of a tank block-out mechanism in the sump in a 
somewhat restricted space. 
The device of the above U.S. Pat. No. 5,730,115, acts to prevent flareup by 
providing a float in the fuel chamber, which float rises in response to 
the presence of excess fuel in the fuel chamber. As the float rises, it 
moves a member which obturates an opening from the sump to the chamber, 
causing the opening into the fuel chamber to be closed. Should the float 
fail to respond, or if the opening does not seal properly, excess fuel 
will continue to flow into the chamber, which may result in flareup. 
The device of the above U.S. Pat. No. 5,772,425, prevents flareup by 
containing vapors in the sump area when the removable fuel tank is 
inserted into the fuel chamber. A gasket contains vapors present in the 
sump area when the tank is seated in the sump opening. When the tank is 
removed from the sump opening, a plate moves upward due to the action of a 
spring and contains vapors in the sump area. While this device is quite 
effective in preventing flareup due to vapor migration from the sump area, 
it does not prevent flareup should excess fuel enter the fuel chamber, 
causing an overflow of fuel from the fuel chamber. 
The device of the above U.S. Pat. No. 5,551,865 of Henderson and Henderson 
employs a thermocouple/solenoid/lever system, which lever must be engaged 
until the wick flame is established sufficiently such that the solenoid 
can maintain the position of the lever so that it does not actuate the 
automatic wick extinguishing mechanism. Should excess fuel enter the fuel 
chamber, a float causes the thermocouple/solenoid circuit to open, which 
releases the lever, actuating the wick extinguishing mechanism. This 
device has the advantage that there is a self-test of the system each time 
the burner is operated. On the other hand, the device requires electrical 
circuitry and components for its operation. Also, should the wick 
extinguishing mechanism fail to operate, flareup may result. 
OBJECTS AND ADVANTAGES 
Accordingly, several objects and advantages of the present invention are to 
provide an improved and safer wick-fed, barometric, liquid fuel burner, to 
provide such a burner with a safety device which does not require the 
reduction in capacity of the removable fuel tanks does not require the 
redesigning of the fuel chamber to increase its capacity, does not require 
electrical power or electronic circuitry, does not require the presence of 
excessive heat for its actuation, is applicable to kerosene heaters that 
do not have fuel lines, and provides for the metering of the flow of fuel 
from the removable fuel tank, without requiring any modification of the 
burner other than the removable fuel tank. 
In addition, the present burner is quite simple in design and inexpensive 
to incorporate, does not have any substantially increased weight, will 
save lives and property, will make barometric liquid fuel burners easier 
to market because of added safety value, and will likely reduce the number 
of expensive lawsuits prompted by injury, loss of life, and property 
damage. 
Still further objects and advantages will become apparent from a 
consideration of the ensuing description and drawings.

DRAWING REFERENCE NUMERALS 
10 Cabinet 
12 Tank guide 
14 Basetray 
16 Support 
18 Support 
20 Reflector 
22 Heat shield 
24 Inner equalization tube 
26 Lid 
28 Outer equalization tube 
30 Chamber 
32 Plate 
34 Orifice 
36 Opening 
38 Wick gear 
40 Fuel chamber 
42 Automatic wick extinguishing unit 
44 Fill tube 
46 Vibration-sensing weight 
48 Combustion cylinder 
50 Inner wick guide 
52 Outer wick guide 
54 Wick 
56 Fuel 
58 Wick fuel supply reservoir 
60 Removable fuel tank 
62 Plunger 
64 Opening 
66 Plunger spring 
68 Tank cap 
70 Pin 
72 Plunger head 
74 Opening 
76 Opening 
78 Support 
80 Support 
82 Support 
84 Support 
86 Neck 
88 Opening 
A Normal fuel level 
B Flooded fuel level 
SUMMARY 
In accordance with the present invention, an anti-flareup safety device for 
wick-fed, barometric liquid fuel burners regulates the flow of fuel from 
the removable tank into the fuel chamber, which prevents excess amounts of 
fuel from entering the fuel chamber, thereby preventing the flooding of 
the fuel chamber and flareup. 
The safety device includes a fuel containment system in the removable tank 
to hold and restrict fuel egress from the removable tank. The system 
consists of a plate with an orifice, a fill tube, an inner equalization 
tube, an outer equalization tube, and a chamber. 
Conventional Heater Structure--FIG. 1 
FIG. 1 is a side sectional view of a conventional wick-fed barometric 
liquid-fuel burner (as described supra) that operates by burning a liquid 
fuel, such as kerosene. The burner is a wick-fed type with a combustion 
cylinder 48 and is constructed in a manner widely known in the art. One 
manufacturer of the burner of FIG. 1 is Toyotomi of Japan, and such 
manufacturer sells such burners under the trademark Kero-Sun. 
In normal operation fuel is delivered from a removable fuel tank 60 to a 
horizontal fuel chamber 40 through an orifice in a tank cap 68 on tank 60. 
Tank 60 is held in a vertical position by tank guide 12 in cabinet 10 in 
accordance with the common practice of the industry. Cap 68, which is 
attached to the neck of tank 60, is inserted into a mating well, or sump, 
in the top surface of chamber 40, also the common practice in the 
industry. 
When the fuel level in chamber 40 drops below level A due to fuel 
consumption by wick 54, air will bubble into tank 60 through orifice 74 in 
tank cap 68, and fuel (e.g., kerosene) will flow from tank 60 into chamber 
40 until the level in chamber 40 reaches level A. A partial vacuum above 
the fuel in tank 60 maintains the fuel in tank 60 above level A until all 
of the fuel has been discharged from tank 60. Fuel 56, which is in fluid 
communication with wick 54, migrates by capillary action up wick 54 and is 
burned inside combustion cylinder 48, which generally consists of inner 
metal cylinders and an outer glass cylinder. Cylinder 48 provides a 
surface for the burning of the fuel, and radiates heat and some light. The 
flame is not shown, but is seen as a red glow in cylinder 48, above the 
wick. 
Wick 54, cylindrical in shape and shown in a partial cross-sectional view, 
can be moved up or down by rotating a wick gear 38. Wick 54, wick guides 
50 and 52, combustion cylinder 48, wick fuel supply reservoir 58, and 
vibration-sensing weight 46 in FIG. 1 are circular in shape when seen from 
above, whereas compartment 40 is generally rectangular. Removable fuel 
tank 60 is most commonly rectangular in shape as viewed from above, but 
various other shapes are also found, such as triangular. Tank cap 68 is 
cylindrical in shape, and is threaded to allow attachment to tank 60. 
The fuel burner has an automatic wick extinguishing unit 42, which includes 
a vibration-sensing weight 46. If the burner is vibrated excessively, unit 
42 disengages wick gear 38, which lowers wick 54, extinguishing the flame, 
or actuates any other wick extinguishing mechanism (not shown). 
Operation and Danger of Flareup with Conventional Burner--FIG. 1 
If the partial vacuum in tank 60 is lost, the barometric system of the 
burner of FIG. 1 no longer regulates fuel flow from tank 60. The partial 
vacuum may be lost by compromise of the integrity of tank 60, or by the 
presence of a high vapor pressure in tank 60, e.g., due to heating of tank 
60. Most flareup incidents occur when a high-volatility fuel is 
inadvertently introduced into tank 60--most commonly, gasoline or 
gasoline-contaminated fuel. As a result, excessive fuel will flow into 
chamber 40. Since the capacity of tank 60 is about two liters (two quarts) 
greater than that of chamber 40, chamber 40 will not be able to contain 
all of the fuel from tank 60, if any significant amount of fuel is present 
in tank 60. As a result, fuel fills chamber 40 and when it reaches level 
B, overflows via opening 64 between tank 60 and the top of chamber 40. 
The fuel spreads over the fuel chamber's surface and to other areas in the 
burner. The flooded fuel will ignite because the vapors from the leaked 
fuel are drawn by air movement toward the wick flame (not shown) in 
cylinder 48, which is of sufficient temperature to ignite these fumes. As 
a result, there will be flames in and around tank 60, causing the pressure 
inside tank 60 to increase dramatically, driving more fuel out of tank 60, 
which further increases the amount of escaped fuel, and accordingly 
increases the severity of the flareup. 
The flareup incidents involving high-volatility fuels do not occur 
immediately after the burners are lit, but usually after an induction 
period of one or more hours. There is a delay because these burners are 
utilized for heating purposes at cooler ambient temperatures. At such 
temperatures, even the high-volatility fuels have vapor pressures low 
enough that the partial vacuum above the liquid in tank 60 is adequate to 
maintain the column of fuel in the tank, which requires a pressure 
differential of only approximately 3 kPa (0.4 psi) for the 36 cm (14 in) 
height typical of removable tanks. 
For example, at 21.degree. C. (70.degree. F.) the vapor pressure of the 
most volatile class of gasolines Class E, is on the order of 69 
kiloPascals (kPa), that is, about 10 pounds per square inch (psi). Since 
ambient pressure is around 101 kPa (14.7 psi), a column of gasoline nearly 
5 m (15 ft) high could be maintained at such a pressure differential. 
However, should the temperature of the gasoline reach 38.degree. C. 
(100.degree. F.)--the approximate boiling point of gasoline--its vapor 
pressure will increase to about 101 kPa (14.7 psi), and the fuel will flow 
out of the removable tank and into the fuel chamber in an uncontrolled 
manner. This will circumvent the normal operation of the barometric valve. 
The increase in temperature of the air space in the removable tank during 
operation of the burner is not a significant factor in the loss of the 
partial vacuum in the removable tank. This is because the temperature 
increases are not rapid enough to overcome the normal action of the 
barometric valve in controlling fuel flow from tank 60 as fuel is consumed 
by the wick. 
Unless the burner is in a very low temperature environment, the temperature 
of the removable tank will typically exceed 38.degree. C. (100.degree. F.) 
during operation of the burner. The removable tank achieves such 
temperatures due to its proximity, about 13 cm (5 in), to the combustion 
process, which reaches temperatures in excess of 850.degree. C. 
(1600.degree. F.), During operation of the burner, heat is transferred by 
radiation, convection, and conduction processes from the combustion 
cylinder to the removable tank. 
The typical flareup scenario in such burners is as follows: Initially, the 
fuel in the removable tank is at a low enough temperature so that its 
vapor pressure is insufficient to allow liquid to flow from the removable 
tank beyond that allowed by the barometric valve. At this point, the 
liquid level in the fuel chamber will be maintained at the level of the 
barometric valve, which allows fuel to flow from the removable tank into 
the fuel chamber only as fuel is consumed by the wick. The temperature of 
the removable tank, as well as the fuel inside it, increases as thermal 
equilibrium is established in the burner, causing the vapor pressure of 
the fuel to increase. Then the increased vapor pressure of the fuel 
compromises the partial vacuum inside the removable tank, allowing fuel in 
the removable tank to flow into the fuel chamber in an uncontrolled 
manner. Since the capacity of the removable tank (4-5 liters) far exceeds 
that of the fuel chamber (1-2 liters), the fuel chamber fills and 
overflows. The vapors from the spilled fuel ignite and flareup ensues. 
There is a second mechanism for flareup when high-volatility fuels are 
present. Vapors present in the sump area can be drawn to the wick flame by 
air currents, where they are ignited. Flames in the sump area heat the 
removable tank, causing it to dump its fuel in an uncontrolled manner, 
resulting in flareup. 
With the exception of the above Henderson and Lightsey device (U.S. Pat. 
No. 5,338,185), the above Henderson tank-lift, pin drop, thermal 
barrier/fuel containment, vapor containment/tank-block, float/fuel shutoff 
and sump vapor containment devices (U.S. Pat. Nos. 5,456,595, 5,409,370, 
5,549,470, 5,662,468, 5,730,115, and 5,772,425, respectively) and the 
above Henderson and Henderson device (U.S. Pat. No. 5,551,865), prior-art 
safety devices do not prevent flareup, but rather detect evidence that 
flareup has begun, and then trigger an automatic wick extinguishing unit, 
which acts to extinguish the flame on the wick. However, by the time 
flareup has begun, flames are outside the wick area, and extinguishment of 
the wick flame does not affect the progression of flareup. The flames are 
present where fuel has flooded, and the increasing amounts of fuel being 
discharged from the removable tank further increase the magnitude of the 
flareup incident, as described earlier. 
The Henderson and Lightsey device (U.S. Pat. No. 5,338,185) is designed to 
extinguish the flame on the wick prior to flareup. However, if the wick 
shutoff mechanism fails to operate when activated as a result of the wick 
becoming encrusted, this device may not be able to prevent flareup. The 
Henderson tank-lift and pin-drop devices (U.S. Pat. Nos. 5,456,595 and 
5,409,370, respectively) are designed to shut off fuel flow from the 
removable tank to the fuel chamber by separating the removable tank from 
the pin that opens the barometric device in the cap on the removable tank 
cap. However, these two devices have one feature in common: should they 
not operate properly to stop fuel flow from the removable tank, the fuel 
chamber may overflow and flareup may result. 
The Henderson thermal barrier/fuel containment device (U.S. Pat. No. 
5,549,470) is a very simple and effective device; however, fuel vapors in 
the vicinity of the removable tank may migrate over the walls of the fuel 
containment sump, which surrounds the removable tank, and may be drawn to 
the wick flame by the air movement in the burner, where they could be 
ignited. Also, the added components will increase the weight of the 
burner. The Henderson vapor containment/tank block mechanism (Ser. No. 
08/514,583) is quite simple and effective. However, in order to contain an 
amount of fuel equal to the full capacity of the removable tank, this 
device requires either a) the incorporation of two additional compartments 
(beyond the fuel chamber), or b) the incorporation of one additional 
compartment, and an increase in the capacity of the fuel chamber. The 
Henderson sump vapor containment device (U.S. Pat. No. 5,472,425) acts to 
contain vapors in the sump area. Should excess fuel enter the fuel 
chamber, however, flareup may not be prevented. 
The Henderson and Henderson thermocouple/solenoid device (U.S. Pat. No. 
5,551,865) provides a self-test of the system each time the burner is 
operated. However, it requires incorporation of electrical circuits and 
components, and depends upon the proper functioning of the automatic wick 
shutoff mechanism. The Henderson float/fuel shutoff device is designed to 
block fuel flow into the fuel chamber when excess fuel is lost from the 
removable tank. Should the float not respond, or if the opening for fuel 
flow does not close properly, flareup may result. 
Thus, prior-art safety devices, such as those which monitor excessive 
vibration of the burner, which detect high levels of CO.sub.2 and low 
levels of O.sub.2, which detect abnormal combustion, and which regulate 
the position of the wick to prevent excessive flaming, are ineffective in 
preventing flareup. The safety device described in the Josephs patent, 
supra, does not prevent flareup, but rather provides a wick-drop 
mechanism, and cuts off fuel flow through a fuel line after the onset of 
flareup. Since the wick-fed barometric liquid fuel burners in common use 
do not utilize a fuel line, Josephs' device is not applicable to them. 
The Henderson and Lightsey, and the Henderson tank-lift, pin-drop, and 
float/fuel shutoff devices (U.S. Pat. Nos. 5,338,185, 5,456,595, 
5,409,370, and 5,730,115, respectively) are designed to prevent flareup, 
but should they not operate properly, flooding of the fuel chamber may 
occur, and flareup may result. In the case of the Henderson thermal 
barrier/fuel containment device (U.S. Pat. No. 5,549,470), the additional 
components will increase the weight of the burner. To be most effective, 
the Henderson vapor containment/tank block device (U.S. Pat. No. 
5,662,468) requires either the incorporation of two separate compartments 
as an adjunct to the fuel chamber, or an increase in the capacity of the 
fuel chamber and incorporation of one additional compartment. The 
Henderson vapor containment device (U.S. Pat. No. 5,662,468) may not 
prevent flareup should excess fuel enter the fuel chamber. The Henderson 
and Henderson thermocouple/solenoid device (U.S. Pat. No. 5,551,865) is 
designed to actuate the wick shutoff mechanism. However, should that 
mechanism fail to respond, e.g., due to the wick becoming encrusted, 
flareup may result. 
Description of Inventive Anti-Flareup Device--FIG. 2 
Thus while many types of safety devices are known, these devices have not 
yet been incorporated in liquid fuel burners; accordingly, flareups and 
fires continue to occur, causing loss of life, injury, and property 
damage. An improvement over the earlier anti-flareup devices which 
overcomes the problem of loss of excess fuel from the removable tank due 
to high-volatility fuels, and thereby reduces the likelihood of flareups 
and fires, is illustrated in FIG. 2, which shows a removable and 
refillable tank with our inventive addition. It operates by providing a 
system that regulates fuel flow from a removable fuel tank 60 into the 
fuel chamber (not shown but similar to that of FIG. 1). It includes the 
following conventional elements: a tank cap 68, a plunger 62, a plunger 
spring 66, and a plunger head 72. In the typical fashion, as tank 60 is 
lowered into cabinet 10, pin 70 contacts plunger head 72, forcing it 
backward into cap 68, thereby allowing fuel in tank 60 to flow into fuel 
chamber 40. 
In addition, tank 60 includes additional elements which constitute a 
preferred embodiment of the present inventive anti-flareup safety device. 
A plate 32 is located inside tank 60 near neck 86. Plate 32 extends 
completely across tank 60, and is liquid tight in its attachment to tank 
60. Plate 32 is generally oval in shape. Its dimensions are about 15 cm (6 
in) by 10 cm (4 in), and its thickness is about 0.25 cm (0.1 in). An 
orifice 34 is present in plate 32. Orifice 34, which is circular in shape, 
extends through plate 32, and is approximately 0.025 cm (0.01 in) in 
diameter. 
In addition, a fill tube 44 is coupled with orifice 34 in plate 32 and 
extends upward from plate 32, terminating near the top of tank 60. Tube 
44, which is cylindrical, is about 2.5 cm (1 in) in diameter and some 20 
cm (8 in) long, with a wall thickness of around 0.1 cm (0.04 in). An inner 
equalization tube 24 is located inside tube 44, extending from near 
opening 74 through the opposite end of tube 44, at which point tube 24 
connects to the top of the side of chamber 30. Tube 24, which is 
cylindrical, is about 20 cm (8 in) long and 0.5 cm (0.2 in) in diameter. 
Outer equalization tube 28 is slightly shorter (19 cm (7.5 in)) and wider 
(1 cm (0.4 in)) than tube 24. Tube 28 is connected to the bottom of 
chamber 30, and extends along the outside of tube 44, terminating just 
above plate 32. Chamber 30 is cylindrical and is about 5 cm (2 in) long 
and 2.5 cm (1 in) in diameter. Tube 24 is connected to fill tube 44 by 
supports 78 and 80, and tube 28 is connected to tube 26 by supports 82 and 
84. 
Supports 78, 80, 82 and 84 have dimensions of about 1 cm (0.4 in) by 1 cm 
(0.4 in), and a thickness of 0.25 cm (0.1 in). Plate 32, tube 24, tube 28, 
tube 44, chamber 30, and supports 78, 80, 82 and 84 are preferably metal. 
Operation of Inventive Anti-Flareup Device--FIG. 2 
After operation of the burner for a period of time, tank 60 will become 
depleted of fuel, and the wick flame will extinguish. Should further 
operation of the burner be desired, it is necessary that tank 60 be 
refueled. The refueling procedure consists of removing tank 60 from the 
burner, inverting the tanks removing cap 68, and introducing fuel into 
tank 60. As fuel enters tank 60, it will flow through opening 74 in fill 
tube 44, and begin to fill tank 60. The air in tank 60 that is being 
displaced by the fuel will exit the tank through opening 88 and out tube 
44, until fuel covers opening 88. As fuel continues to enter tank 60, air 
will flow into opening 76, and through equalization tube 28, chamber 30 
and equalization tube 24, ultimately egressing through opening 36. Thus 
tube 28, chamber 30, and tube 44 constitute an air-equalization system for 
allowing tank 60 to be filled even though the fuel covers opening 88 in 
fill tube 44. 
After the fueling process is completed, cap 68 is replaced on tank 60, 
which is inverted and inserted into the burner in the usual fashion. The 
fuel inside tube 44 will flow to the vicinity of cap 68, where it passes 
through the barometric valve. The fuel outside tube 44 and above plate 32 
must pass through orifice 34 before it can pass through the barometric 
valve. Makeup air to replace the fuel passing through orifice 34 enters 
through tube 44. The fuel flow through orifice 34 will not be affected by 
pressure variations inside tank 60, even if a high-volatility fuel is 
present. This is because tube 44 provides equilibration to both sides of 
plate 32, where orifice 34 is located. 
Should tank 60 contain some fuel above plate 32 at the time of re-fueling, 
tube 28 will contain some fuel. When tank 60 is inverted in order to 
refuel it, the liquid in tube 28 will flow into chamber 30, which 
accommodates that fuel, and thus no fuel enters tube 24. In this way, 
during the fueling operation the passageway comprised of tube 24, chamber 
30, and tube 28 will be clear of liquid. In addition, the passageway will 
not be subject to a siphoning action after tank 60 has been filled, and is 
inverted and inserted into the burner. 
After ignition of the wick, the burner components begin to increase in 
temperature. The hottest location in the burner components is in the 
vicinity of cylinder 48, especially over it. During operation of the 
burner, tank 60 (FIG. 1) and the fuel inside, will become warmer, causing 
the vapor pressure of the fuel to increase. If a high-volatility fuel, 
such as gasoline, is present in tank 60, the vapor pressure of the fuel in 
tank 60 will increase to the point that the partial vacuum above the fuel 
will become compromised. The fuel inside tube 44 and below plate 32 will 
escape in an uncontrolled manner. On the other hand, the fuel above plate 
32 that is outside tube 44 will be contained, and its flow through orifice 
34 is not affected by pressure changes. Orifice 34 is sized such that it 
restricts fuel flow to a rate comparable to the fuel consumption rate. 
ADVANTAGES 
It is clear from the discussion above that the anti-flareup safety device 
is quite simple in constructions and can be readily incorporated in the 
removable fuel tanks of wick-fed barometric liquid fuel burners without 
affecting the remainder of the burner. Yet it will prevent flareup by 
providing a system that regulates the flow of fuel from the removable fuel 
tank. 
The present device prevents the burning of fuel outside its intended site, 
that being at the wick, thereby saving fuel and reducing odor. Also, the 
device does not require any electrical power or electronic circuitry for 
the prevention of flareup. The device is quite simple, and it can readily 
be incorporated in the removable tanks in contemporary burners. 
Clearly, the device will make wick-fed, barometric liquid fuel burners 
safer to operate, and accordingly, will at the same time reduce the 
expensive lawsuits resulting from flareup incidents, and will reduce the 
incidence of injury, loss of life, and property damage. As a result these 
burners will be easier to market. 
RAMIFICATIONS AND SCOPE 
Those skilled in the art can now appreciate from the foregoing description 
that the broad teachings of the present invention can be implemented in a 
variety of forms. Therefore, while the safety device has been described in 
connection with particular examples thereof, the true scope of the 
invention should not be so limited since other modifications will become 
apparent to the skilled practitioner upon a study of the drawings, 
specification and following claims. 
For example, the shape and composition of the safety device can be varied, 
so long as its function is preserved. 
Fill tube 44, inner equalization tube 24, outer equalization tube 28, and 
chamber 30 may have various cross-sectional shapes, such as square, 
rectangular, oval or other convenient shapes, and their locations may be 
changed, so long as their functions are preserved. Also, the diameter of 
tube 44 may be changed, so long as the opening is sufficient to allow fuel 
to be readily introduced into tank 60. The capacities of tube 24, tube 28, 
and chamber 30 may be varied, so long as the capacity of chamber 30 
exceeds that of tube 28, and so long as air can flow readily through tube 
24, tube 28, and chamber 30 during the fueling of tank 60, so as not to 
interfere with the fueling operation, and the diameter of tube 24 must be 
greater than that of tube 28. 
The orifice may be located in some other location in the plate than that 
shown, and it may be one opening, or may consist of multiple openings, or 
it may be replaced with a tube or multiple tubes. 
Also, the device may be connected to or used in combination with other 
safety devices, such as warning gauges, tank block features, or shutoff 
mechanisms. 
Thus the scope of the invention should be determined, not by the examples 
given, but by the appended claims and their legal equivalents.