|
(11) | EP 0 188 874 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||||||
| (54) | Fuel tank heating systems |
| (57) Several embodiments of fuel tank heating systems are described which are particularly
adapted to be removably installed within fuel oil drums and which warm the interior
contents of the drum enabling the fuel to be conveniently withdrawn in conditions
where they are exposed to cold ambient temperatures leading to fuel waxing and solidification.
According to one embodiment of the invention, a combustion-type heating device is
installed within a port of the drum which uses fuel from the drum to support a flame.
Heat transfer units conduct heat from the flame into the drum, thereby warming the
interior contents. According to a second embodiment of this invention, a fuel outlet
conduit is positioned within the fuel drum and is preferably in close proximity with
heating units, thereby enabling fuel to be withdrawn from the interior contents of
the drum. Further, a fuel pump may be submersed within the tank and connected to the
fuel outlet conduit. Each of the systems described may be conveniently installed within
drain ports of fuel oil drums of conventional configuration. |
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] This invention relates to fluid heating devices and particularly to such devices adapted for heating fuel within a reservoir thereby enabling the fuel to be conveniently withdrawn in conditions of exposure to cold ambient temperatures.
[0002] Hydrocarbon fuels are often stored in reservoirs which are subjected to cold ambient temperatures. At sufficiently low temperatures, fuels and particularly fuel oils, become viscous and develop parrafin or wax particles. Fuel oils have characteristic temperatures at which they become "cloudy" due to the presence of suspended wax crystals and at which they "freeze" or become a semi-solid mass, referred to as their cloud and pour points, respectively. Some fuel oils have a cloud point of 20 degrees Farenheit and a pour point of 0 degrees Farerheit. Often fuel oils are stored in conditions where they are exposed to these critical temperatures.
[0003] In cold temperature conditions, fuel containing drums my be used to provide fuel for stationary generating plants powered by diesel cycle internal combustion engines or gas turbine engines, or for other types of stationary combustion devices such as furnaces. Additionally, fuel is often stored in drums at fuel depots which support motor vehicle field operations. After prolonged exposure to cold temperatures, fuels within storage vessels can reach their pour point and become an essentially immovable mass of fully waxed fuel. In this condition, it is very difficult to remove fuel from the storage drums. In order to overcome these problems, users will often attempt to warm the contents of the fuel vessel by applying external heat to the vessel or will insure that they are maintained in a warmed enclosure. Often such measures require the vessels to be moved or handled requiring time and effort.
[0004] In view of the above, it is an object of this invention to provide systems which enable rapid warming of the contents within a fuel storage reservoir enabling the fuel to be poured or drawn as needed. It is a further object of this invention to provide such systems which may be conveniently and removably attached to a standard configuration fuel containing drum. It is a further object of this invention to provide such systems which employ a minimum of canponents, which are simple in construction, and which may be provided at a low cost.
[0005] The above objects of this invention are achieved by providing a device which may be attached to a conventional fuel containing drum inlet and outlet opening. According to one embodiment of this invention, a combustion type heater is installed within the fuel drum opening which uses fuel within the drum to warm heat transfer devices which conduct heat into the interior of the drum. In another embodiment of this invention, a fluid pump is provided to assist in fuel withdrawal. A heating device is placed in close proximity with the fuel inlet which warms the fuel, thereby providing liquid fuel which may be pumped from the interior of the drum.
[0006] Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE
[0007]
Figure 1 is a perspective view of a conventional fuel oil storing tank with which this invention is particularly adapted and showing a fuel tank heating system according to a first embodiment of this invention attached thereto;
Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1 showing a fuel tank heating system according to a first embodiment of this invention which employs a combustion heating system to warm fuel within the tank; and
Figure 3 is a cross-sectional view of a fuel tank heating system according to a second embodiment of this invention showing a fuel pump and heating device installed within the tank.
DETAILED DESCRIPTION OF THE INVENTION
[0008] Figure 1 illustrates a conventional drum 12 of the type often used to store fuel oils. Drum 12 of the type shown is often referred to as a "55-gallon" drum and includes a circular port 14 having a threaded flange 16. A removable threaded cap (not shown) is typically used to permit filling and draining of drum 12. As stated previously, once the fuel within drum 12 has reached a sufficiently low temperature, it becomes very difficult to withdraw the fuel. This invention describes several embodiments of systems which permit fuel to be removed from such drums conveniently and rapidly. Although the devices described herein are disclosed as being useful for use with drum 12 of the type shown in Figure 1, this invention is equally usable for any type of fluid containing vessel wherein heating and removal of the fluid is desired.
[0009] A first embodiment of a fuel tank heating system 18 is shown in Figure 2. This device includes a combustion-type heater which uses fuel within drum 12 to support combustion which is used to warm the interior contents of the drum. Fuel tank heating system 18 includes an elongated hollow sleeve 20 which is received at its lower end by end cap 22. End cap 22 and sleeve 20 are conveniently attached to the periphery of port 14 by threaded attaching ring 24. Wick support 26 is attached to or made integrally with end cap 22. Wick support 26 positions wick 28 which extends into drum 12. Vent holes 30 are provided within sleeve 20 to permit the conduction of fresh air into the sleeve to support combustion therein. Heat transfer units 32 may be any type of component which has the desirable heat transfer characteristics and are also supported by end cap 22. Heat transfer units 32 could be made of a solid rod of a high-heat conductivity metal. Alternately, so-called heat pipes or beat tubes could be used which have a hollow fluid filled interior. Such heat pipes or heat tubes would be particularly useful due to their high heat transfer efficiency. Heat transfer units 32 are configured to have an upper end 34 in close proximity with the flame emanating from wick 28, thereby becoming heated during combustion. Lower end 36 of heat transfer units 32 extend within the interior of drum 12, and transfer heat to the fuel. The lower end 36 of the heat transfer units may be bent to a generally horizontal direction as shown in Figure 2 in order to provide optimal heat transfer to the fuel. Heat transfer units 32, however, may be formed in any desired configurations and may, for example, extend near the bottom surface of drum 12 or may extend to an intermediate position within the drum. It is desirable, however, that heat transfer units 32 be configured so that the entire unit may be installed within port 14, so that the device may be used without requiring modifications to drum 12.
[0010] In use, the conventional threaded cap attached to threaded flange 16 is removed from drum 12 and fuel tank heating system 18 is installed as - shown in Figure 2. Since drums are usually stored with their drain port up, it is normally unnecessary to handle or move the drums in order to make use of fuel heating system 18. Wick 28 preferably is soaked with a small amount of liquid fuel for rapid ignition. Sleeve 20 is removable and enables convenient lighting of wick 28. Once the wick begins to burn, sleeve 20 is reinstalled and the fuel warming process begins. Beat transfer units 32 warms the interior contents of drum 12 including fuel in the vicinity of wick 28, thereby providing liquified fuel which supports combustion within sleeve 20. A fuel tank heating system 18 is therefore provided which is simple in construction and which may be installed within a conventional fuel drum port. The device is further essentially self-powered since it uses fuel drawn from drum 12 rather than requiring an external source of energy. Once the fuel within drum 12 is sufficiently warmed, fuel tank heating system 18 can be completely removed and the contents poured or otherwise withdrawn from the interior of drum 12.
[0011] Numerous variations of fuel tank heating system 18 are within the scope of this invention. For example, heating systems 18 may be designed for other configurations of drum openings or other types of vessels. Furthermore, with simple modifications, a separate fuel containing cup (not shown) can be provided immediately below end cap 22 for holding a small amount of fuel taken from the drum to support combustion in those instances where the drum is only partially filled and in which case it would be difficult to conduct fuel along a long length of wick 28.
[0012] A second embodiment of a fuel tank heating system 118 is shown in Figure 3. This embodiment varies principally from the first in that, in addition to warming the tank contents, the device further includes means for withdrawing the fuel. Attaching ring 124 and end cap 122 are employed to support the components of this system. Heat transfer units 132 used in connection with this embodiment may be of any type such as those described previously but preferably is in the form of electrically powered resistance heating units. Further, heat transfer units 132 could function like those of the first embodiment through employing a combustion heat source. Fuel outlet conduit 44 is provided having an inlet opening in close proximity with heat transfer units 132. As a further means of enabling the withdrawal of fuel from within drum 12, pump assembly 38 is also provided. Pump assembly 38 includes an externally mounted pump motor 40 which drives a fuel pump 42, preferably of a positive displacement type such as a gear pump. Pump tube 48 is supported by end cap 122 and extends between the motor and pump. An internal rotating drive shaft (not shown) communicates energy between the motor and pump. Pump 42 includes an outlet passage which is connected to the inlet of fuel conduit 44. It has been found that a fuel pimp such as the type shown in Figure 3 is capable of providing liquid fuel even though subnersed within heavily solidified fuel due to the shearing action which occurs within the pump which tends to liquify the fuel. This shearing action in conjunction with the heating effect provided by heat transfer units 132 enables the rapid withdrawal of liquified fuel fran the drum. Like the first embodiment, components which become mounted within the interior of drum 12 are preferably configured so that they can be conveniently inserted and withdrawn through a conventional fuel drum port 14. The operation of heating system 118 proceeds like that described previously in that the existing cap covering threaded flange 16 is removed and the entire unit is installed within port 14. Thereafter, energy is supplied to heating unit 46 to liquify fuel in the vicinity of fuel pump 42 thereby providing it with warmed and liquified fuel. This fuel is thereafter conducted through outlet conduit 44 into an associated fuel combustion device or intermediate fuel reservoir.
1. A heating system adapted for warming the contents of a vessel containing a combustible
fuel comprising;
an end cap attached to the vessel,
a wick support associated with said end cap,
a wick positioned by said wick support and extending into the vessel, said wick support and said wick cooperating to sustain a flame, and
heat transfer means for transferring heat from the flame to the contents of the vessel.
2. The heating system according to Claim 1 further comprising a sleeve mountable to
said vessel enclosing said end cap, said wick support and said wick.
3. The heating system according to Claim 2 wherein said sleeve is removable from said
end cap thereby facilitating access to said wick.
4. The heating system according to Claim 1 wherein said heat transfer means comprises
one or more elongated heat transfer units having a portion exposed to said flame and
another portion extending into said vessel.
5. The heating system according to Claim 4 wherein said heat transfer units comprise
one or more metal rods.
6. The heating system according to Claim 4 wherein said heat transfer units comprise
one or more heat tubes.
7. The heating system according to Claim 4 wherein said heat transfer units are configured
to be removably inserted within said vessel.
8. A heating system adapted for warming the contents of a vessel containing a combustible
fuel, the vessel of the type having a port in a surface thereof with a peripheral
flange, the heating system being removably attached to said vessel port flange and
comprising;
an end cap,
means for removably fastening said end cap to the port peripheral flange,
a wick support associated with said end cap,
a wick positioned by said wick support and extending into the vessel, said wick support and said wick cooperating to sustain a flame, and
heat transfer means for transferring heat from the flame to the contents of the vessel.
9. The heating system according to Claim 8 wherein said means for removably fastening
said end cap comprises a threaded ring which meshes with corresponding threads of
the drum port flange.
10. The heating system according to Claim 8 further comprising a sleeve mountable
to said vessel enclosing said end cap, said wick support and said wick.
11. The heating system according to Claim 9 wherein said sleeve is removable from
said end cap thereby facilitating access to said wick.
12. The heating system according to Claim 8 wherein said heat transfer means comprises
one or more elongated heat transfer units having a portion exposed to the flame and
another portion extending into said vessel.
13. The heating system according to Claim 12 wherein said heat transfer units comprise
one or more metal rods.
14. The heating system according to Claim 12 wherein said heat transfer units comprise
one or more heat tubes.
15. A heating system adapted for warming the contents of a vessel of the type having
a port in a surface thereof with a peripheral flange and for permitting dispensing
of the fuel from the vessel, the heating system being removably attached to the vessel
port, the heating system comprising;
an attaching ring removably attachable to said vessel port peripheral flange,
an end cap attached to said vessel within the port by said attaching ring,
heating means supported by said end cap and extending into the vessel, and
a fuel outlet conduit supported by said end cap and having an inlet end in close proximity with said heating means, said heating means and said outlet conduit configured to permit insertion into and withdrawal from the port.
16. The heating system according to Claim 15 further comprising;
a fuel pump mounting tube supported by said end cap,
a fuel pump attached to said mounting tube having a fuel inlet and fuel outlet, said fuel outlet connected to said outlet conduit,
a pump motor connected to said mounting tube, and
a drive shaft within said fuel pump mounting tube for transmitting energy from said motor to said pump, said fuel pump mounting tube, and fuel pump configured to permit insertion into and withdrawal from said port.
17. The heating system according to Claim 15 wherein said heating means comprises
an elongated electrical resistance heater.