1. Field of the Invention
This invention relates generally to a self-contained device for generating heat through combustion of a non-pressured, high flash point fuel (&gt;100.degree. F.) utilized primarily for heating food and the like. More particularly, this invention pertains to a closed cartridge containing a reservoir of a novel high percentage glycol or glycol derivative fuel and a non-consumable wick immersed in the fuel reservoir to provide controllable means for combusting said glycol or glycol derivative. These devices are commonly found in applications utilizing chafing dishes where food is to be maintained at an elevated termperature for extended periods of time.
2. Description of the Prior Art
Restaurants and others involved in the food preparation industry typically have a requirement for maintaining various foodstuffs at an elevated temperature for extended periods of time to maintain said food's edibility as well as to preserve the food from infection by exogenous microorganisms.
Prior art means for maintaining foods at elevated temperatures include cartridges and canisters containing alcohol fuels such as methyl and ethyl alcohol;. Said alcohol fuels have relativley low flash points, typically in the range 54.degree. F. to 56.degree. F., which permit these fuels to be ignited directly by flame provided by a match or a candle. These types of prior art devices have several inherent drawbacks which create substantial problems for their users.
Most significant among the disadvantages to prior art devices are those encountered in the field of product safety. Utilization of methyl and ethyl alcohols creates a substantial hazard due to fire. This fact arises from the high volatility and low falsh point of these one and two carbon alcohols.
A second significant safety concern is that of noxious vapors. Those prior art devices utilizing methyl alcohol as their fuel present a substantial hazard with respect to methanol vapors. Said vapors are toxic and additionally can contaminate any food stored or located in the vicinity of these devices.
The third safety consideration is that of shipping. Prior art devices containing methanol and ethanol as their fuels have various restrictions placed upon them by those authorities regulating common carriers and other shippers. Thus, prior art devices are more expensive and inconvenient to transport due to the inherent hazards presented by their fuels.
Additionally, prior art devices present a disadvantage in that the range of heat developed by such devices is not easily adjustable. Most prior art devices is not easily adjustable. Most prior art devices utilize various mechanical means to adjust the oxygen flow available for combustion of the methanol and ethanol. This arrangement for control of heat is inadequate in many cases where a very low flame is required because the amount of oxygen required for low flame cannot be adequately regulated using prior art mechanical means thus causing the flame to be often spontaneously extinguished.
Therefore, it is desireable to provide a burner device for controllably heating and warming food and the like utilizing a new and unique, clean burning, high percentage glycol or glycol derivative fuel having a low vapor pressure and high flash point relative to commonly used fuels such as methanol and ethanol. Moreover, it is desirable that such a burner utilize a fuel which is nontoxic and produces a low level of nontoxic vapors. It is also desirable that such an improved heating device should have a continually adjustable flame by controlling the amount of fuel available for combustion.
While the prior art recognizes that glycol or glycol derivatives can be used as fuel additives; these additives are in minimal amounts (i.e. concentrations measured in parts per million) and are included to enhance the characteristics of the primary fuel component. In addition, glycol or glycol derivatives in substantial concentrations have never before been used, or suggested for use, as the primary fuel component.
Finally, it is desirable to provide a burner that is safe to ship and use and has minimal regulatory restrictions on shipment and storage relative to prior art devices.