Data processing: generic control systems or specific application – Specific application – apparatus or process – Mechanical control system
Reexamination Certificate
1999-07-07
2001-08-07
Gordon, Paul P. (Department: 2121)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Mechanical control system
C454S239000, C454S061000
Reexamination Certificate
active
06272399
ABSTRACT:
FIELD OF THE INVENTION
The present invention is related to controllers. More specifically, the present invention is related to a method, system and an apparatus for fume hood controllers. The controllers can be networkable, or qualitatively tuned or based on face velocity and sash position of the fume hood.
BACKGROUND OF THE INVENTION
Laboratories wherein dangerous experiments or processes are performed require protection for the workers and the experiments in the laboratory. One very common protection found in laboratories are fume hoods in which chemical reactions are conducted. The fume hoods have air drawn out of them thus essentially preventing any toxic fumes from escaping the fume hood into the laboratory and threatening the operators. The velocity of air drawn through the fume hood sash is controlled to a value high enough to maintain safety for the operator and low enough to provide non-turbulent air for the experiment of process.
An additional protection that can be provided is to maintain the static pressure in the laboratory at a lower or higher pressure than the pressure in the surrounding corridors of the building. A lower pressure would prevent contaminants from exiting the laboratory in the case of an accident.
A higher pressure would prevent contaminants from entering the laboratory, as is the case in a clean room. Also, control of the laboratory climate is required both for operator comfort and for certain experiments or processes where strict temperature and humidity control are necessary.
Moreover, in regard to the tuning of a processor, for instance, for fume hoods, there exists automatically tunable processors which respond to the system into which they are integrated. But after the processor is initially tuned to its system, to tune it in terms of how a user would like the processor to respond with respect to the system, the user must be fluent in operation of the operating system of the processor in order to retune it.
There are many schemes and apparatuses that provide such control and protection to laboratories. However, heretofore, there have been no systems that provide for integrated direct digital control of laboratories. Additionally, there have been no systems that are automatically tunable based on simple manual inputs to the system.
Furthermore, heretofore, fume hoods typically have utilized the sash position as an integral part of the determination for face velocity or flow. The present invention eliminates the need to know sash position to determine face velocity or flow.
SUMMARY OF THE INVENTION
The present invention pertains to a system for controlling a fume hood with a face. The system comprises means for controlling air flow through the fume hood based on air flow face velocity. The controlling means has means for measuring pressure at the face of the fume hood which produces a signal corresponding to the pressure. Additionally, the system comprises a controller. The controller is remote from the fume hood controlling means but in communication with the controlling means.
The present invention also pertains to a system for controlling a fume hood having a face. The system comprises a pitot tube assembly for determining a desired face velocity. The pitot tube produces a pitot signal corresponding to the face velocity. The system comprises means for converting the pitot signal into a face velocity signal. The converting means is connected to the pitot tube. Additionally, the system comprises a processor for controlling air flow through the fume hood based on the face velocity. The processor is connected to the converting means.
The present invention also pertains to a method for controlling air flow through a fume hood having a face. The method comprises the steps of sensing velocity of air at the face of the fume hood with a pitot tube assembly. Then there is the step of controlling air flow through the fume hood based on the velocity of air at the face of the fume hood.
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Information Disclosure Statement/Declaration of Linda Diss and attachments thereto Sep. 12, 1997.
Information Disclosure Statement/Declaration of Richard Fish and attachments thereto Sep. 11, 1997.
“Face Velocity Control Systems” brochure by Anemostat, copyrighted in 1984.
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Arnold Bruce D.
Fish, Jr. Richard W.
American Auto-Matrix, INc.
Garland Steven R.
Gordon Paul P.
Reed Smith LLP
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