Air supply and exhaust adapter for combustion apparatus

In an air supply and exhaust adapter for a combustion device of a forced air supply and exhaust type, with the combustion device comprising an air supply section and an exhaust section being provided to project from a top plate portion of an outer casing; comprising a base portion that comprises a box shaped configuration and an open bottom portion, an air supply intake portion that is formed on the top surface portion of the base portion so as to cover the air supply section and to take in air from the surroundings of the combustion device, a circumferential wall portion that surrounds the periphery of the exhaust section; and a communication passage defined between the top surface portion and the top plate portion so as to communicate the space between the exhaust section and the circumferential wall portion with the air supply intake portion; the communication passage being constructed so that, due to the operation of the air blower means, the gauge pressure therein becomes negative.

BACKGROUND OF THE INVENTION

The present invention relates to an air supply and exhaust adapter that is attached to an air supply aperture and to an exhaust aperture of a combustion device.

Conventionally, hot water supply devices and room heating devices have been widely used that perform hot water supply and/or space heating by employing natural exhaust type (CF: Conventional Flue type) combustion devices that are installed inside a building, and that combust fuel by taking in air from within the building and discharge the combustion exhaust gases to the exterior of the building by the force of natural venting. An exhaust pipe that communicates with the exterior is provided to the building, and, since the exhaust unit of the CF type combustion device is connected to the exhaust pipe, accordingly the combustion exhaust gases can be discharged to the exterior.

When a combustion device of this CF type is to be replaced with a new one, sometimes, from the viewpoint of maintaining the external appearance of the building, there are cases that it is not possible to remove an exhaust pipe that is already in existence. In such a case, one solution is to replace the combustion device by inserting a new exhaust pipe into the interior of the exhaust pipe that is already in existence.

For example, the exhaust construction for a combustion device of Japanese Patent Publication 5,884,865 is connected to an exhaust unit of a forced exhaust type (FE: Forced Exhaust type) combustion device that combusts fuel by forcibly sucking in air from the inside of the building with a blower fan, and that vents the resulting combustion exhaust gases to the outside. This exhaust construction makes it possible to discharge combustion exhaust gases to the outside by passing an exhaust conduit through the interior of an exhaust pipe that is already in existence, and also prevents the intrusion of rain water by disposing an air supply and exhaust adapter in the space between the exhaust pipe and the exhaust conduit. Moreover, this space is connected to a connection port that is provided on the outer casing of the combustion device, and, by utilizing the negative gauge pressure within the outer casing that is generated during operation of the blower fan, it becomes possible to send combustion exhaust gases that have leaked out into the space between the exhaust pipe and the exhaust conduit back into the combustion device for a second time.

However, when it is not possible to remove the already existing exhaust pipe, it is often not possible to provide a new air supply pipe. For this reason, it may not be possible to replace a CF type combustion device or an FE type combustion device with a forced air supply and exhaust type (FF: forced flue or forced draft balanced flue type) combustion device that sucks in outdoor air from an air supply pipe with a blower fan, combusts fuel, and discharges the exhaust to the exterior, which in recent years has become a mainstream type. Accordingly, it is necessary to provide a FE type combustion device as a replacement, and this constitutes a burden upon the supplier of combustion equipment.

Even if an FF type combustion device is installed by passing a new exhaust conduit through an exhaust pipe that is already in existence, so that air inside the building is sucked in and the exhaust gases are discharged to the exterior of the building, there is a danger that the exhaust gases may leak from the exhaust conduit to the interior of the building. Since, with the exhaust construction for a combustion device described in above patent publication, the space between the exhaust pipe and the exhaust conduit is connected to a connection port on the outer casing of an FE type combustion device in order to prevent leakage of the combustion exhaust gases into the building, accordingly, normally, this exhaust construction cannot be applied to an FF type combustion device that is not provided with any connection port of this type on its outer casing for introduction of outdoor air.

An object of the present invention is to provide an air supply and exhaust adapter which makes it possible to employ an FF type combustion device in a safe manner by utilizing an exhaust pipe that is already in existence, even in a site in which it is not possible to install an air supply pipe.

SUMMARY OF THE INVENTION

The present invention presents an air supply and exhaust adapter for a combustion device of a forced air supply and exhaust type, with the combustion device comprising an air supply section and an exhaust section being provided to project from a top plate portion of an outer casing; comprising a base portion that comprises a box shaped configuration and an open bottom portion, an air supply intake portion that is formed on a top surface portion of the base portion so as to cover the air supply section and that moreover takes in air from a surroundings of the combustion device, a circumferential wall portion that surrounds a periphery of the exhaust section, and a communication passage defined between the top surface portion and the top plate portion so as to communicate a space between the exhaust section and the circumferential wall portion with the air supply intake portion; the communication passage being constructed so that, due to an operation of the air blower means, a gauge pressure therein becomes negative.

According to the structure described above, an FF type combustion device to which this air supply and exhaust adapter is installed can be installed and operated in a similar manner to an FE type combustion device. Moreover, it is possible to prevent leakage of the combustion exhaust gases to the interior of the building in which the combustion device is installed, since it is possible to send any combustion exhaust gases that have leaked out from the exhaust conduit back to the air supply intake portion and to prevent the leaked exhaust gases from leaking to the exterior of the building.

In a preferable first aspect of the present invention, the combustion device comprises a combustion section and a heat exchange section and an air blower means for supplying air for combustion to the combustion section which are provided within the outer casing of the combustion device, and the air supply section supplies air to the air blower means, and the exhaust section discharges combustion exhaust gases after heat exchange,

In a preferable second aspect of the present invention, a filter is provided to the air supply intake portion.

According to the second aspect, along with eliminating foreign matter within the air that is introduced into the combustion section, it is also possible to generate a negative gauge pressure in the air supply intake portion.

Thus, according to the present invention, it is possible to provide an air supply and exhaust adapter with which an FF type combustion device can be utilized in a safe manner by using an exhaust pipe that is already in existence, even in a location in which it is not possible to install an air supply pipe.

DETAILED DESCRIPTION

In the following, an embodiment of the present invention will be described on the basis of attached drawings. In the figures, the arrow U refers to the upward direction, the arrow F refers to the forward direction, and the arrow L refers to the leftward direction.

First, an FF type combustion device1will be explained.

As shown inFIG. 1, the combustion device1comprises a box shaped outer casing2, and, in this outer casing2, a combustion section3, a heat exchange section4, an air blower means5, an air supply section6, an exhaust section7, and so on are installed. The air supply section6and the exhaust section7are disposed so that portions thereof project upward from the top plate portion2aof the outer casing2. The air blower means5supplies air taken into the outer casing2from the air supply section6to the combustion section3as air for combustion. The combustion section3combusts fuel supplied from a fuel supply conduit10together with the air for combustion, and thereby generates combustion exhaust gases. In the heat exchange section4, these combustion gases exchange heat with fluid that flows in from an intake pipe8. After heat exchange, the combustion gases are ejected from an exhaust section7as exhaust gases. And working fluid that has exchanged heat in the heat exchange section4with these combustion exhaust gases flows out through an outlet pipe9.

Although this feature is omitted from the figure, normally, the air supply section6and the exhaust section7of the combustion device1are respectively connected to an air supply pipe and to an exhaust conduit, both of which communicate with the outdoors. Accordingly, normally the combustion device1takes in outdoor air with the air blower means5and combusts fuel, and exhausts combustion exhaust gases to the outdoors.

Next, an air supply and exhaust adapter11will be explained.

As shown inFIGS. 2 through 4, the air supply and exhaust adapter11comprises a base portion12that is formed in the shape of a box with its bottom surface portion open, an air supply intake portion13that is provided on a top surface portion12aof the base portion12, and a cylindrical circumferential wall portion14. A flange portion12bis formed along the external periphery of the bottom surface portion of the base portion12, and a seal member15is disposed on the lower surface of the flange portion12b, so that it can be secured to the top plate portion2aof the outer casing2in an air-tight manner.

The top surface portion12ais provided with an air supply opening portion12cand an exhaust opening portion12d, through which the air supply section6and the exhaust section7are respectively inserted, and air supply section fixing portions12e,12fand exhaust section fixing portions12g,12hare respectively provided to these opening portions and can be fixed by screws or the like to the air supply section6and the exhaust section7that are respectively inserted therethrough as described above. The air supply opening portion12cis fitted over the air supply section6that is inserted therethrough. And a cutaway portion12iis formed on the periphery of the air supply opening portion12con its side toward the exhaust opening portion12d, and is cut away so that a clearance is established between that part of the periphery and the air supply section6that is inserted through the opening portion12c.

The air supply intake portion13is formed in a box shape whose bottom portion is open, and is installed to the top surface portion12aso as to cover the air supply section6that projects from the air supply opening portion12c. A filter13aformed as a mesh is provided at the front surface portion of the air supply intake portion13. Foreign matter included in the air that is being sucked through this filter13ainto the air supply intake portion13is removed by the filter13a.

The exhaust opening portion12dis formed to have a diameter greater than the external diameter of the exhaust section7. Exhaust section fixing portions12g,12hare formed to project radially inward from the edge of the exhaust opening portion12d. Due to this, a gap is defined between the exhaust opening portion12dand the exhaust section7that is inserted through it. The circumferential wall portion14is formed as a cylinder and follows the periphery of the exhaust opening portion12d. The exhaust section7can be inserted through the interior of the circumferential wall portion14, and a duct16described later can be connected to the circumferential wall portion14.

Next, the installation of the combustion device1that employs this air supply and exhaust adapter11will be explained.

As shown inFIG. 5, a cylindrical exhaust pipe20is provided to a building B and communicates from the interior of the building B to its exterior. A duct16is connected to the end portion within the building B of the exhaust pipe20, and an exhaust conduit17is inserted through the interiors of the exhaust pipe20and the duct16. And, at the end portions of the exhaust pipe20and the exhaust conduit17exterior to the building B, a protective cap21for preventing intrusion of rain water or the like is installed between the exhaust pipe20and the exhaust conduit17. The combustion device1is installed in this building B.

As shown inFIGS. 1 and 4, the base portion12is installed to the top plate portion2aof the combustion device1, and, along with the air supply section6being passed through the air supply opening portion12cand being fixed by screws to the air supply section fixing portions12e,12f(not shown in the figure), also the exhaust section7is passed through the exhaust opening portion12dand the circumferential wall portion14and is fixed by screws e to the exhaust section fixing portions12g,12h(also not shown in the figure). Subsequently, by attaching the air supply intake portion13which covers the air supply section6to the base portion12, the fitting of the air supply and exhaust adapter11to the combustion device1is completed. A filter member6ais installed to the lower end portion of the air supply section6.

The exhaust section7is connected to the exhaust conduit17that passes through the interior of the exhaust pipe20, and communicates with the exterior of the building B. Since the exhaust conduit17is to be passed through the exhaust pipe20which is already in existence, it is desirable for it to be a conduit member that is flexible, and for example to be made from a synthetic resin such as polypropylene or the like. In order to make the task of connecting the exhaust section7and the exhaust conduit17together simple and easy, an extension member7ais installed in advance to the exhaust section7so as to elongate the portion of connection with the exhaust conduit17to a position higher than the circumferential wall portion14, and the exhaust section7is connected to the exhaust conduit17via the extension member7a.

The duct16that is connected to the exhaust pipe20is connected to the circumferential wall portion14. The space between the exhaust pipe20and the exhaust conduit17communicates, via the space between the duct16and the exhaust conduit17and via the space between the circumferential wall portion14and the exhaust section7, with a communication passage18that is defined within the base portion12between its top surface portion12aand the top plate portion2a. Via the cutaway portion12i, the communication passage18communicates with the air supply intake portion13. The duct16is a flexible duct that, for example, may be made by forming a sheet member in which a synthetic resin sheet and an aluminum sheet are laminated together into the form of a cylinder, together with reinforcing wire. Due to this construction, it is possible to bend the duct16and to form it to follow along the exhaust conduit17which is passed through it, while still maintaining the outer diameter of the duct16.

Next, the operation and the beneficial effects of the air supply and exhaust adapter11of the present invention will be explained.

The air supply and exhaust adapter11is installed to the top plate portion2aof the outer casing2of the combustion device1. The circumferential wall portion14of the air supply and exhaust adapter11that surrounds the exhaust section7of the combustion device1is connected via the duct16to the exhaust pipe20which is already in existence. And the exhaust section7of the combustion device1is communicated with the exterior of the building B via the exhaust conduit17that is inserted through the interior of the exhaust pipe20.

The space between the exhaust pipe20and the exhaust conduit17is blocked at their end portions exterior to the building B by the protective cap21. This space is communicated to the air supply intake portion13by the communication passage18within the base portion12of the air supply and exhaust adapter11, via the space between the duct16and the exhaust conduit17and the space between the circumferential wall portion14and the exhaust section7. The communication passage18and the air supply intake portion13are communicated with one another through the cutaway portion12i.

When the air blower means5is operated, air within the building B can be taken into the air supply intake portion13via the filter13a, so that the air within the building B can be employed as the air supply for the combustion device1. At this time, due to the ventilation resistance of the filter13a, the pressure at the air supply intake portion13becomes negative with respect to the atmospheric pressure inside the building, and, via the communication passage18, the gauge pressure in the space between the duct16and the exhaust conduit17also becomes negative. Even if combustion exhaust gases leak from the exhaust conduit17into this space, it is possible to prevent leakage of these gases to the interior of the building B, since these leaked exhaust gases are taken into the combustion device1for a second time via the communication passage18and are then discharged to the exterior of the building B through the exhaust section7and the exhaust conduit17. Accordingly, even if it is not possible to provide an air supply pipe that communicates with the exterior of the building B, with this air supply and exhaust adapter11, it is possible to install the combustion device1in the interior of the building B by utilizing the exhaust pipe20which is already in existence, and it is possible to utilize this combustion device1in a safe manner.

The combustion device1explained above is capable of serving as a hot water supply device and/or a room heating device, and can be built so that heat is supplied by the heat exchange section4to hot water and/or to a room heating thermal medium. Apart from the above, for a person skilled in the art, it would be possible, without deviating from the gist of the present invention, to implement the present invention in various forms by making additions of various types to the embodiment described above, and the present invention is to be considered as encompassing modifications of this kind.