Measuring and testing – Volume or rate of flow – Using differential pressure
Reexamination Certificate
2002-06-10
2004-08-03
Lefkowitz, Edward (Department: 2855)
Measuring and testing
Volume or rate of flow
Using differential pressure
Reexamination Certificate
active
06769310
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to flow indicating devices and, more particularly, to a simplified flow-indicating device and associated mechanism and method.
2. Description of Related Art
Flow-indicating devices for high-purity fluids may often be expensive and complicated devices due to the construction and configuration factors which must be taken into account so as to minimize contamination of the fluid. In some instances, in order to automatically obtain a desired flow of such a high-purity fluid, a suitable rotometer (otherwise referred to herein as a flow meter) is used with a separate optical detector or sensor for detecting when the flow has reached a certain level. That is, the flow meter typically includes a flow element which is moved along a graduated scale as the flow increases. The optical sensor is disposed externally to the flow meter and senses when the flow has reached a certain level by detecting the position of the flow element. However, some rotometers may require extensive machining and fitting of components to provide a calibrated flow. Accordingly, due to the nature of such a rotometer, entire units must be used for each application. For example, a rotometer used one application for one fluid may not be readily and interchangeably used in a second application for a second fluid due to cross-contamination concerns.
In other situations, the rotometers may include components which, as a result of the design of the flow meter, contact the fluid or otherwise comprise a pathway between the external environment and the fluid flowing within the flow meter, thereby introducing the risk of fluid contamination. Further, since the optical sensor is a separate component which must be suitably secured in correspondence with the flow meter in order to sense a particular and calibrated flow. Accordingly, any disruption of the relationship between the optical sensor and the flow meter, such as to replace the optical sensor or to move the optical sensor to a different position to detect a different desired flow rate, may require another complete calibration when the device is returned to service.
Thus, there exists a need for a simple, low-cost flow-indicating device, such as a flow meter or flow switch. Such a device should desirably be readily adaptable to various applications without having to replace the entire unit. Further, such a device should desirably remain functionally calibrated for successive applications or replacement of components. In addition, the device should desirably be configured so as to minimize the risk of contamination of the fluid.
BRIEF SUMMARY OF THE INVENTION
The above and other needs are met by the present invention which, in one embodiment, provides a mechanism for forming a flow-indicating device. Such a mechanism comprises a shaping block adapted to operably engaged a tubular body having opposed ends, wherein one of the ends is a downstream end, so as to form a constricted portion therebetween. The body is adapted to direct a flow therethrough and is adapted to have a flow element disposed therein. The constricted portion of the body formed by the shaping block thereby defines a constricted orifice having a downstream side, wherein the constricted orifice is configured to prevent the flow element from passing therethrough and has the flow element disposed on the downstream side thereof. The shaping block is further configured with respect to the body such that the flow element engages the constricted orifice when the flow is below a flow rate and moves toward the downstream end of the body as the flow increases over the flow rate to thereby indicate the flow through the body.
Another advantageous aspect of the present invention comprises a flow-indicating device having a tubular body adapted to direct a flow therethrough. The body has opposed ends, with one end being a downstream end, and has a flow element disposed therein. A shaping block is operably engaged with the body so as to form a constricted portion between the ends, wherein the constricted portion of the body defines a constricted orifice having a downstream side. The constricted orifice is configured to prevent the flow element from passing therethrough and has the flow element disposed on the downstream side thereof. The shaping block is further configured with respect to the body such that the flow element engages the constricted orifice when the flow is below a flow rate and moves toward the downstream end of the body as the flow increases over the flow rate to thereby indicate the flow through the body. A processing device may be operably engaged with the sensor in order to receive the signal therefrom and to perform a task in response thereto.
Yet another advantageous aspect of the present invention comprises a method of forming a flow-indicating device. First, a shaping block is operably engaged with a tubular body, wherein the body is adapted to direct a flow therethrough and has opposed ends, with one end being a downstream end. A constricted portion is thereby formed between the ends and defines a constricted orifice having a downstream side. A flow element is disposed within the body on the downstream side of the constricted orifice, wherein the constricted orifice is configured to prevent the flow element from passing therethrough. The shaping block is configured with respect to the body such that the flow element engages the constricted orifice when the flow is below a flow rate and moves toward the downstream end of the body as the flow increases over the flow rate to thereby indicate the flow through the body.
Thus, embodiments of the present invention provide a flow-indicating device, such as a flow meter or flow switch, which may be simply and cost effectively produced. Since the device is comprised of a shaping block externally engaging a tubular body, the body may be readily replaced or interchanged with another similar tubular body without having to replace the entire unit. Further, since the shaping block includes the sensor(s) for detecting the flow through the body, the shaping block remains functionally calibrated for successive replacement bodies. In addition, since the shaping block and the sensor(s) only externally engage the body and do not come in contact with the flow, an advantage in maintaining the purity of the flow may be realized. Thus, embodiments of a flow-indicating device according to embodiments of the present invention provide significant advantages as further detailed herein.
REFERENCES:
patent: 5186058 (1993-02-01), Lew
patent: 5820715 (1998-10-01), Singleterry et al.
patent: 6338279 (2002-01-01), Tsataros
Lefkowitz Edward
The BOC Group Inc.
Thompson Jewel
Zebrak Ira Lee
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