1. Technical Field
The invention relates to built-in vacuum cleaning systems in which a power unit containing a motor and a debris collection system is connected to various wall outlets through piping extending throughout the building. More particularly, the invention relates to such a power unit and to a sound reducer mounted in the unit to enhance the cooling and reduce the sound of the vacuum supplying motor mounted in the unit.
2. Background Information
Built-in vacuum cleaning systems are well-known in the building and cleaning industry and consists of a main power unit usually mounted in the basement or a garage for proper air circulation. The power unit contains a motor and a debris collection receptacle with various filters. When the motor is turned on, it creates a suction or vacuum at a plurality of wall outlets for drawing in dust and debris which is carried through tubing located in the walls of the building to the power unit where it is subsequently filtered and the cleaned air exhausted either to the outside or to a specific area in the building. Some examples of these in-wall vacuum cleaning systems are shown in U.S. Pat. Nos. 2,943,698 and 4,938,309. One problem with these types of systems is that the size of the motor required to generate the desired amount of vacuum can be relatively noisy when in operation which is annoying to the user thereof. Also it is desirable to provide adequate cooling for the motor to provide maximum efficiency and long motor life.
Thus, there has been a need to reduce the sound transmitted by the air vacuum motor by providing the unit with various types of sound dampening means while providing optimum cooling of the motor. Some examples of prior art systems having sound reducing means are shown in U.S. Pat. Nos. 2,731,194, 2,948,210, 4,786,299, 4,938,309, and 5,400,463. Although some of these cleaning systems and power units may have successfully dampened a certain amount of sound transmitted to the surrounding environment by the use of foam inserts, increased sound reduction is always desirable and with a less expensive and less complicated and bulky sound reducer than heretofore believed available. Also such foam inserts should not reduce the cooling of the motor by blocking the air passages thereto. The present invention is believed to achieve this result by the unique sound reducers described herein below.