Drying and gas or vapor contact with solids – Apparatus – For diverse operations on treated material
Reexamination Certificate
1999-12-10
2001-06-12
Wilson, Pamela (Department: 3749)
Drying and gas or vapor contact with solids
Apparatus
For diverse operations on treated material
C034S084000, C034S218000, C118S715000
Reexamination Certificate
active
06243966
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a mechanical device utilizing a venturi effect for amplifying flow of air there through, and more particularly, to an air amplifier device having an output air flow of high uniformity and which is accurately aligned with the axis of the device.
BACKGROUND OF THE INVENTION
Semiconductor processing equipment chambers have walls which during certain processing steps need to be cooled. Existing methods of providing such cooling include circulating chilled water through pipes in contact with the chamber walls and of blowing of air against an exterior surface or surfaces of the walls. These cooling methods and arrangements are relatively complex and costly, and in some instances required periodic maintenance which caused down-time of the equipment which adds to the costs of manufacturing.
An air amplifier which utilize a venturi effect and has no moving parts is commercially available from the TRTX Co. of Cincinnati, Ohio. However, prior-art devices of this kind fail to provide an output pattern of air flow of sufficient uniformity to be fully suitable for use in cooling the exteriors of walls of processing chambers of semiconductor manufacturing equipment. The cooling of such walls should be as uniform and even as possible in order to prevent hot spots and temperature variations.
It is desirable an air amplifying device provide cooling air directed over and upon the walls of semiconductor processing chambers which has a uniform flow pattern accurately aligned relative to the chamber in order to provide even temperature distributions.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a device for amplifying a flow of air. The device utilizes a venturi effect and has an output air flow pattern with improved uniformity and more precise alignment. This improved device comprises a body with an inner, cylindrical wall defining a relatively large, central cavity extending down along an axis. At one end of this cavity there is an entrance opening for sucking atmospheric air into and axially down through the device. At the other end of the cavity there is an exit opening from which the air is discharged in a uniform and precisely aligned pattern and with an “amplified” flow rate. Located within the cavity near the entrance opening is an annular venturi opening which passes through the inner wall of the device from the central cavity to an enclosed air chamber behind the wall. The venturi opening is very precisely formed and dimensioned by an upper circular lip and a lower parallel lip. These lips are closely spaced apart from each other in the axial direction, and are formed by edges at a cut through the inner wall. The lips lie closely parallel to each other and slope somewhat downward and inward toward the center cavity. The venturi opening defined by these lips is made dimensionally highly uniform for 360 degrees around their lengths which are concentric with the center axis. This venturi opening directs a set stream of controlled air at relatively high velocity downward into the central cavity, which stream by venturi action sucks a much larger volume of air from the outside atmosphere into the entrance opening of the device. The controlled stream of air is provided by pressurized clean, dry air pumped into the enclosed air chamber from an external source. This produces an overall “amplified” stream of air at the exit opening of the device having a flow rate (measured in standard cubic feet per minute) many times (e.g., twenty times) the flow rate of the controlled air stream. The near perfect uniformity of the air stream exiting from the device is such that, by way of example, temperature variation at selected points around the wall of a processing chamber is only about 1° C. compared to variations of as much as 15° C. with prior art air amplifier devices. The device provided by the present invention is advantageously made as two generally cylindrical pieces which telescope together and which have abutting shoulders which index and hold them in precise dimensional relationship. This in turn insures that the venturi opening of the assembled device is perfectly uniform (or nearly so) for 360 degrees around the periphery of the central cavity and results in an “amplified” air flow from the device of precise alignment and uniformity.
Viewed from a first aspect, the present invention is directed to an air amplifier device. The devices comprises a body having a first inner wall defining a generally cylindrical cavity having a center axis and an entrance opening at a first end thereof and an exit opening at a second end thereof. The body defines a pair of separated circular lips having first ends which intersect the inner wall near the entrance opening and form a venturi jet opening through the inner wall. The lips are uniformly parallel with each other and concentric with the center axis and being closely and uniformly spaced apart for 360 degrees around their lengths. The body defines a channel there through which has first and second ends with the first end thereof being in communication with second ends of the lips. The channel is adapted to allow air under pressure to flow into the first end thereof and there through and then into the jet air opening such that a jet of controlled air flows evenly through the jet opening and sucks atmospheric air into the entrance opening of the device and results in a highly uniform amplified flow of air out from the exit opening of the device.
Viewed from a first aspect, the present invention is directed to an air amplifier device. The devices comprises a body having two pieces fastened together and having a first inner wall defining a generally cylindrical cavity having a center axis and an entrance opening at a first end thereof and an exit opening at a second end thereof. The two pieces have respective shoulders which abut to index the pieces in precise relationship radially, axially, and longitudinally. The body defines a pair of separated circular lips having first ends which intersect the inner wall near the entrance opening and form a venturi jet opening through the inner wall. The lips are uniformly parallel with each other and concentric with the center axis and are closely and uniformly spaced apart for 360 degrees around their lengths. The lips are a circular edge of each of the two pieces and are indexed to the respective shoulders of the pieces such that when the pieces are assembled the jet air opening is uniform within a fraction of a thousandth of an inch. The body defines a channel there through which has first and second ends with the first end thereof being in communication with second ends of the lips. The channel is adapted to allow air under pressure to flow into the first end thereof and there through and then into the jet air opening such that a jet of controlled air flows evenly through the jet opening and sucks atmospheric air into the entrance opening of the device and results in a highly uniform amplified flow of air out from the exit opening of the device.
A better understanding of the invention together with a fuller appreciation of its many advantages will best be gained from a study of the following description given in conjunction with the accompanying drawings and claims.
REFERENCES:
patent: 5843233 (1998-12-01), Van De Ven et al.
patent: 6099650 (2000-08-01), Carbonaro et al.
Floyd Edward
Lubomirsky Dmitry
Applied Materials Inc.
Ostroff & Associates
Wilson Pamela
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