Heating – With work cooling structure
Reexamination Certificate
2000-08-03
2001-10-02
Wilson, Gregory (Department: 3749)
Heating
With work cooling structure
C432S173000, C432S233000, C126S10400A
Reexamination Certificate
active
06296478
ABSTRACT:
BACKGROUND OF THE INVENTION
(i) Field of the Invention
This invention relates generally to furnaces and particularly to cooling a motor that drives a draft inducing fan in a furnace. The invention provides for an improved method of cooling the motor that drives the fan and an apparatus for practicing the method.
(ii) Description of the Related Art
Typically, fans driven by an electric motor are used to induce an air flow in a furnace. These fans are designed to produce a certain amount of air flow which is used to remove the products of combustion in a gas-fired furnace and provide a flow of heated air through a heat exchanger. The air flow induced by these fans does not come in contact with the motor and therefore, does not contribute to the cooling of the motor nor dissipation of the heat generated by the motor.
in typical prior art furnaces, the fan motor is located in the vestibule of the furnace which also houses the electronics and controls for controlling the furnace. The heat generated by the blower motor elevates the temperature within the vestibule. The elevated temperature within the vestibule can shorten the life of the electronics and controls located within the vestibule. Additionally, the excess heat generated by the motor can shorten the life of the motor itself.
Typical prior art furnace fans utilize a motor that has an auxiliary fan attached to the rotating shaft of the motor to cool the motor. The auxiliary fan forces a flow of air to flow across the motor to dissipate the heat generated by the motor. An auxiliary fan, however, has many disadvantages.
One disadvantage is that the auxiliary fan increases the size or height of the motor assembly thereby preventing the streamlining of the motor assembly and the associated furnace within which the motor assembly is used. Another disadvantage is that the use of an auxiliary fan produces an additional load on the motor which can reduce the overall motor efficiency and increase the energy consumption of the furnace in which is it used. Furthermore, the use of an auxiliary fan increases the cost of providing the draft inducing fan. Another disadvantage is that the auxiliary fan can generate additional noise which may require the furnace within which it is used to incorporate additional sound deadening techniques. Finally, because the motor is typically used in a vestibule, the air flow induced by the auxiliary fan is channeled into the vestibule thereby contributing to the elevated temperature of the vestibule and the associated components residing therein.
Therefore, it is an object of the present invention to provide an apparatus and method for cooling the motor that eliminates the need for an auxiliary fan.
SUMMARY OF THE INVENTION
The present invention overcomes shortcomings of prior art furnaces that use an auxiliary fan attached to the motor to cool the motor driving the draft inducing fan by providing a furnace that cools the motor with the flow of air induced by the draft inducing fan. By eliminating the need for an auxiliary fan, the present invention allows for the motor and fan assembly to be more compact and streamlined than the prior art motor, fan and auxiliary fan assemblies. Additionally, the present invention reduces the overall cost of providing a means to cool the motor while reducing the noise associated with cooling the motor with only a minimal load being placed on the motor.
In general, the furnace of the present invention is comprised of a motor which resides in a housing having at least one inlet and at least one outlet. A fan is driven by the motor and resides in a fan housing. The fan housing is operatively connected to and communicates with the motor housing and is configured and adapted to cause a flow of air to flow through the motor housing prior to entering the fan housing, thereby cooling the motor.
More specifically, the furnace is comprised of a motor in a motor housing having at least one inlet and at least one outlet. A combustion chamber has at least one inlet and an outlet with the at least one combustion chamber inlet being operatively connected to and communicating with the at least one motor housing outlet. A heat exchanger has an inlet and an outlet with the heat exchanger inlet being operatively connected to and communicating with the combustion chamber outlet. A fan driven by the motor resides in a fan housing and the fan housing has an inlet and an outlet. The heat exchanger outlet is operatively connected to and communicates with the fan housing inlet. The fan causes a flow of air to flow into the motor housing through the at least one motor housing inlet, around the motor, and exit the motor housing through the at least one motor housing outlet. The flow of air then flows into the combustion chamber through the at least one combustion chamber inlet, through the combustion chamber, and exits the combustion chamber through the combustion chamber outlet. The flow of air then flows into the heat exchanger through the heat exchanger inlet, through the heat exchanger, and exits the heat exchanger through the heat exchanger outlet. The flow of air then flows into the fan housing through the fan housing inlet and exits the fan housing through the fan housing outlet. The flow of air cools the motor as it flows through the motor housing and around the motor without the need for an auxiliary fan.
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patent: 5834869 (1998-11-01), Morgan et al.
patent: 6021775 (2000-02-01), Dempsey et al.
patent: 6216685 (2001-04-01), Payne
patent: 6231311 (2001-05-01), Gatley et al.
Howell & Haferkamp LC
Jakel Incorporated
Wilson Gregory
LandOfFree
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