| 摘要 |
<p>In the operation of construction vehicles, noise within the cab of the vehicle has become an increasing concern. The primary source of noise within the cab is created by the operation of the heating, ventilating and air conditioning system that controls the environment of the cab. It is common practice, in present day systems, to utilize duct work within the system that inherently creates a relatively large restriction for the air that flows therethrough. As a result of the air flow restrictions, the blower fans must operate at high speed or alternatively, multiple blowers must be used to provide adequate air flow within the cab. All of these factors combine to create a large source of noise that an operator must endure. The air circulatory system (32) of the present invention utilizes a means (46) for communicating ambient air into the cab and a means (73) to introduce air that is circulating within the cab into the system through passageways (48, 50, 70, 34) that create very little restriction for the air flowing therethrough. A means (76) is utilized to discharge to air back into the cab (10) that also creates very little restriction for the air flow. These results in a very small drop in air pressure between the air being introduced into the blower assembly (40) and the air exiting the blower assembly (40). Subsequently, the requirements of the blower assembly (40) and the noise created by its operation kept at a minimum.</p> |
