EP0262263A1

EP0262263A1 - An air heating apparatus

Info

Publication number: EP0262263A1
Application number: EP86201715A
Authority: EP
Inventors: Joannes Marie Van Heel
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-04-04
Filing date: 1986-10-02
Publication date: 1988-04-06
Anticipated expiration: 2006-10-02
Also published as: DE3687754T2; NL8501003A; NL192632B; EP0262263B1; NL192632C; DE3687754D1; ATE85693T1

Abstract

An apparatus for heating air, comprising a substantially cylindrical housing, including means for conducting the air to be heated therethrough and means for heating said air, the latter means including at least one hot-water reservoir arranged throughout the major part of the length of said housing. Said reservoir includes a supply and a discharge pipe and means for heating the water in the at least one reservoir. The ratio of the outside diameter to the length of the reservoir ranges between 1:3 and 1:30.

Description

The present invention relates to an air heating apparatus comprising a housing including means for conducting air to be heated through the housing and means for heating the air conducted through the housing.
In prior air heating apparatuses, air is usually heated directly by suitable means, e.g. gas burners. A drawback thereof is that relatively large temperature variations may occur. When heated air is necessary, the burners are set in operation automatically or non-automatically and relatively hot air is passed into spaces to be heated. When the desired temperature is reached, the burners are switched off. When transport of air takes place through the apparatus, entirely unheated air will rapidly enter the spaces to be heated, thereby producing cooling. When air transport is discontinued at the same time, cooling will also occur until the burners are reactivated. The heat supply thus takes place shockwise and, with a view to a comfortable heating, steps are necessary to dampen these shocks.
It is an object of the present invention to provide an economically constructed apparatus which is better adapted to effect a uniform supply of heated air to the surroundings.
The object set is achieved according to the present invention with an apparatus in which, in the substantially cylindrical housing, the means for heating the air comprise at least one hot-water reservoir disposed along the major part of the length of the housing, said reservoir including a supply and a discharge pipe, as well as means for heating the water in said at least one reservor, the ratio of outside diameter to the length of the hot-water reservoir ranging between 1:3 to 1:30.
Accordingly, in the apparatus according to the present invention, a hot-water supply is integrated in the hot-air heating system. The air is heated via the hot-water reservoir, which as it were serves as a thermal storage. This makes for a quiet control behaviour and realizes highly uniform heating. The hot-water reservoir in the apparatus according to the present invention should have a slender form in order to ensure optimum heating of the air at a low water capacity. A diameter-to-length ratio of 1:3 is a minimum condition therefor. A low water capacity is required to avoid, as is the case sometimes with conventional storage vessels, boilers and the like, that a large water supply is kept unnecessarily at the required temperature. A small reservoir with such a heat supply, e.g. by means of a gas burner, that when water is being drained off from the reservoir, even during a prolonged period, e.g. for filling a bath, the heating of freshly supplied water, keeps pace therewith, results in a highly economical construction.
Different embodiments of the apparatus according to the present invention are possible. In a suitable embodiment, the walls of the hot-water reservoir are formed by two concentric cylinders, there being provided in the interior of the inner cylinder a space wherein a gas burner is arranged in its bottom portion, and from the top of which combustion gases can be discharged, while between the outer concentric cylinder and the inner wall of the substantially cylindrical housing, there is provided an annular space through which the air to be heated can be conducted. In this embodiment, the annular, cylindrical water reservoir forms so to say a buffer between the combustion space and the space through which the air to be heated is passed.
In a different embodiment of the apparatus according to the present invention, the walls of the hot-water reservoir are formed by two concentric cylinders, the outer concentric cylinder being directly contiguous with the inner wall of the substantially cylindrical housing and there being provided within the inner concentric cylinder a space bounded by a likewise concentric cylinder wall, in which s pace a gas burner is arranged adjacent its lower end and from the top of which combustion gases can be discharged, the inner concentric cylinder and the concentric cylinder wall defining an annular space between them, through which space the air to be heated can be passed, said annular space containing a material having good thermal conductivity and contacting the inner concentric cylinder and the concentric cylinder wall, which material is such that passage of the air to be heated through the annular space is not prevented. In this embodiment, the space for the air to be heated is disposed between the water reservoir and the combustion space. Transfer of heat between the wall of the combustion space and the wall of the water reservoir takes place by the material having good thermal conductivity therebetween, e.g. a network of metal wire or wire mesh. Such a network of relatively thin wires hardly impedes the passage of air through the space.
In still a further embodiment, the apparatus according to the present invention has the form of a cylinder arranged concentrically in the substantially cylindrical housing, with the dimensions of that cylinder being such that between the inner wall of the housing and the outer wall of that cylinder, there is provided an annular space through which the air to be heated can be passed. In yet another embodiment, the walls of the hot-water reservoir are formed by two concentric cylinders, with the outer concentric cylinder being practically directly contiguous with the inner wall of the housing and there being provided within the inner concentric cylinder a space through which the air to be heated can be conducted.
In the last two embodiments, no gas burners are provided for heating the water, but this heating takes place in a different manner, e.g. by electric resistance heating.
Some different embodiments of the apparatus according to the present invention will now be described, by way of example, with reference to the accompanying drawings, in which Figs. 1-4 are cross-sectional views illustrating said embodiments of the present invention.
In the figures, like parts are indicated by the same reference numerals.
The embodiment of the apparatus according to the present invention shown in Fig. 1 comprises a substantially cylindrical housing 1. The wall of the housing 1 consists of a thermally insulating material or of two thin cylinders of sheet metal between which there is sandwiched a thermally insulating material, such as glass wool or the like. Housing 1 is covered at its top by a cover 2, consisting e.g. of the same material, or built up similarly to the cylindrical housing 1. Housing 1 accommodates an annular, cylindrical hot-water reservoir 3 extending throughout the major part of the length of housing 1, e.g. from cover 2 as far as some distance from the underside of housing 1. Reservoir 3 is formed essentially by two concentric metal cylinders 4,5, cylinder 4 of smaller diameter forming the inner wall of reservoir 3 and cylinder 5 of larger diameter forming the outer wall.
Within cylinder 4, forming the inner wall of reservoir 3, there is provided a space 6 serving as a discharge pipe for combustion gases. At the bottom of space 6, near the lower end of reservoir 3, there is arranged a gas burner 7 fed through a gas pipe 8, which is suitably passed through the wall of housing 1 or which is connected to an external gas pipe through the lower end of housing 1. Space 6 for combustion and subsequent discharge of combustion gases is connected to a pipe 9 passed through the cover 2 of housing 1, which pipe 9 may incorporate a damper 10. Pipe 9 may continue downwardly to adjacent burner 7, in which case pipe 9 closely contacts the inner wall 4 of reservoir to ensure a good heat transfer to the water contained in reservoir 3.
At the bottom of reservoir 3, there is provided a cold-water supply-pipe 11, which is passed through the wall of housing 1 in a suitable manner, while at the top of reservoir 3, a hot-water discharge-pipe 12 connects thereto, said pipe 12 being passed e.g. through cover 2.
Between the outer wall 5 of reservoir 3 and the inner wall of housing 1, there is provided an annular space 13 through which air to be heated in the housing can be passed. The air to be heated is drawn in through suitable openings 14 in the wall of the housing 1 near its top end. The intake of air and its movement through space 13 may be effected e.g. by means of a blower 15 disposed at the bottom of housing 1. For collecting dust and the like, a dust filter 16 may be arranged at the bottom of housing 1 above blower 15.
Housing 1 is attached, in any suitable manner, to the floor 17 of a building to be heated. The bottom of housing 1 is open and connects to a channel 18 provided in floor 17 for further transport and distribution of air heated in the apparatus.
In the embodiment shown of the apparatus according to the present invention, the water in reservoir 3 is heated by means of gas burner 7. The air sucked in through openings l4 and subsequently transported through the apparatus is heated by contact with wall 5 of reservoir 3. Because the air is not heated directly by burner 7, a uniform heat supply is possible.
By way of example, the following dimensions for the various parts can be mentioned. The diameter of space 6, approximately equal to the inside diameter of reservoir 3 is 12.5 cm. The diameter of the outer jacket 5 of reservoir 3 is 25 cm. The diameter of housing 1 is 50 cm at the exterior and 35 cm internally. The height of housing 1 as far as the top of cover 2 is 175 cm and the height of reservoir 3 is about 145 cm. The openings 14 are such that with the given dimensions of space 13, fan 15 transports about 250 m³ of air per hour through the apparatus.
The apparatus is further provided with known per se means, not shown, for regulating the temperature of the water in reservoir 3 and for operating gas burner 7 and blower 15 in dependence on the desired functioning.
Fig. 2 shows a modified embodiment of the apparatus according to the present invention. In this variant, reservoir 3 has a larger diameter. The outer wall 5 of reservoir 3 directly abuts on the inner wall of housing 1. Furthermore, reservoir 3 does not extend as far as cover 2 is spaced some distance therefrom, so that the openings 14 lie above reservoir 3. Discharge pipe 12 of reservoir 3, in this variant, is passed through the wall of housing 1.
In this embodiment the annular space 13, through which the air to be heated is conducted, is located between the inner wall 4 of reservoir 3 and pipe 9 for combustion gases, which pipe 9 extends at any rate to around burner 7. The annular space 13 contains a network 19 of metal wire or wire mesh connected to pipe 9 and to cylinder wall 4 of reservoir 3, thereby ensuring a good heat transfer from pipe 9 to reservoir 3.
The following dimensions can be given by way of example. At a height of housing 1 with cover 2 of 175 cm, the outside diameter of housing 1 is about 52.5 cm. The inside diameter of housing 1, which is also the outside diameter of reservoir 3, is 37.5 cm. The inside diameter of reservoir 3 is 27.5 cm and the diameter of pipe 9 is 12.5 cm.
The embodiment of the apparatus according to the present invention shown in Fig. 3 comprises a housing 1 with cover 2 wherein is arranged a cylindrical hot-water reservoir 20 having a supply pipe 11 and a discharge pipe 12. The annular space 13, through which the air to be heated is conducted, is bounded by the inner wall of housing 1 and the outer wall of reservoir 20.
The heating of the water in reservoir 20 in this embodiment takes place for instance by means of electric resistance heating, for which purpose heating coils, not shown, may be arranged in or around reservoir 20. Another possibility is the heating of the water by means of an external b oiler or water heater. To this end, either externally heated water can be supplied through pipe 11, or a heat exchanger may be incorporated in reservoir 20, e.g. by passing externally heated water through reservoir 20 through a coil.
As examples for the dimensions of the variant shown in Fig. 3 can be mentioned a height of housing 1 with cover 2 of about 175 cm, an outside diameter of housing 1 of 35 cm, an internal diameter of 20 cm and a diameter of the cylindrical reservoir 20 of about 10 cm. The height of reservoir 20 may be about 140 cm.
In the embodiment shown in Fig. 4, the annular, cylindrical reservoir 3 is dimensioned in such a manner that the outer wall 4 directly abuts on the inner wall of housing 1. The reservoir extends up to and against the upper wall or cover 2 of housing 1. Within the inner wall 4 of reservoir 3 extends a central channel 21, which is passed through the upper wall or cover 2 of housing 1. The air to be heated is conducted through said central channel 21.
The heating of the water in reservoir 3 in this embodiment takes place in a manner similar to that as described in the above for the variant shown in Fig. 3.
Suitable dimensions of the apparatus shown in Fig. 4, may be: a height of housing 1 with cover 2 of about 175 cm,an outside diameter of housing 1 of 42.5 cm and an internal diameter of 27.5 cm, and an inside diameter of reservoir 3 of 17.5 cm. The height of reservoir 3 may be about 140 cm.
All embodiments are shown to have a single hot-water reservoir. Naturally, it is also possible to arrange a plurality of reservoirs in side-by-side relationship in a single housing, in which case said reservoirs will each be provided with suitable means for heating the water in in said reservoirs.

Claims

1. An apparatus for heating air, comprising a housing having means for conducting air to be heated through the housing and means for heating the air conducted through the housing, characterized in that in the substantially cylindrical housing, the means for heating the air comprise at least one hot-water reservoir arranged through the major part of the length of the housing, said reservoir including a supply and a discharge pipe, as well as means for heating the water in said at least one reservoir, the ratio of the outside diameter to the length of the hot-water reservoir ranging between 1:3 and 1:30.

2. An apparatus according to claim 1, characterized in that the walls of the hot-water reservoir are formed by two concentric cylinders, with the interior of the inner cylinder containing a space wherein a gas burner is disposed in its bottom portion, and from whose top combustion gases can be discharged, the outer concentric cylinder and the inner wall of the substantially cylindrical housing defining between them an annular space through which the air to be heated can be conducted.

3. An apparatus according to claim 1, characterized in that the walls of the hot-water reservoir are formed by two concentric cylinders, with the outer concentric cylinder directly abutting on the inner wall of the substantially cylindrical housing and there being provided, within the inner concentric cylinder, a space bounded by a likewise concentric cylinder wall, in which space a gas burner is provided at its bottom end and from whose top combustion gases can be discharged, the inner concentric cylinder and the concentric cylinder wall defining between them an annular space through which the air to be heated can be conducted, in which annular space is arranged a material of good thermal conductivity which contacts the inner concentric cylinder and the concentric cylinder wall, said material being such that the passage of the air to be heated through the annular space is not prevented.

4. An apparatus according to claim 1, characterized in that the hot-water reservoir has the form of a cylinder arranged concentricall y within the substantially cylindrical housing, with the dimensions of said cylinder being such that between the inner wall of the housing and the outer wall of said cylinder, there is provided an annular space through which the air to be heated can be passed.

5. An apparatus according to claim 1, characterized in that the walls of the hot-water reservoir are formed by two concentric cylinders, the outer concentric cylinder substantially directly abutting on the inner wall of the housing and there being provided, within the inner concentric cylinder, a space through which the air to be heated can be passed.