Communications: electrical – Condition responsive indicating system – Specific condition
Utility Patent
1998-07-24
2001-01-02
Lieu, Julie (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S501000, C340S539230, C703S001000, C703S001000, C703S001000, C703S001000
Utility Patent
active
06169488
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a system for arranging circuits and components for monitoring gases and controlling alarms.
BACKGROUND OF THE INVENTION
Gas detectors protect life and property. In an industrial setting, gas detectors typically use remote sensors so that the presence of any hazardous gas, flammable or toxic, may quickly be detected at a remote location of a facility or process. The presence of a hazardous gas is reported to a control room. The concentration of the gas is analyzed by computer and alarms are automatically activated when the concentration of the gas exceeds certain preset values.
Conventional prior art sensors are individually wired to the field location from a central control panel, using whatever number of wires are required to deliver the power and return the information. There are usually a minimum of three to five wires for each sensor. Wall-mounted boxes interconnect the wiring from the field location to a central computer read-out. As the number of sensors increases, the number of wires to be brought into the read-out area also increases, making the read-out area increasingly complex, and making installation of the sensors and read-out difficult and costly.
Housing for supporting electronics for monitoring large numbers of gas sensors in close arrangements usually occupies a vast amount of wall space and requires expensive conduit, cables, and labor to interconnect.
A major problem in any detection and alarm system is reliability. For the detection and alarm system to be safe, the operator must frequently check and calibrate each sensor. Calibration must be done quite frequently in order to insure accuracy of the sensors. Because sensors for a number of hazardous gases which are lighter than air, such as methane, hydrogen, etc., are sited high above the floor or ground, it is very inconvenient and even dangerous to physically approach the sensor to apply calibration gas and adjust the output.
Leach et al., in U.S. Pat. No. 4,555,930, provide a system for minimizing the number of wires used to connect sensors to a control room. In this case each sensor has its own digital code, so that, when the satellite unit addresses a sensor, the sensor responds with a code that differs from the satellite unit by one parity bit. This system provides zero and span calibration of the sensors. The odd/even parity transmission mode makes it possible to connect a plurality of sensors to a satellite subassembly.
Redding, U.S. Pat. No. 4,119,950, discloses apparatus for monitoring gas content on a site comprising a transmitter for feeding ultrasonic waves through the gas to a receiver. A plurality of transmitter/receiver pairs can be enabled in sequence to monitor a large area, with the respective frequencies or phase displacement monitored by a central processor. There is no indication that the connections to the central processor can be minimized in any way.
Gulbrantson, U.S. Pat. No. 4,067,004, discloses a remote carbon monoxide monitoring system, including a control panel and remote alarm stations. Although the system can be connected to a large number of remote alarm stations, there is no indication that connections to the control panel can be minimized by any type of arrangement.
Klein et al., U.S. Pat. No. 3,090,038, disclose a hazardous atmosphere detecting and signalling system for combustible gases which is less than that which will produce an explosion in the air at that moment. In this apparatus, the gas sampled is enriched with the gas to be detected and exploded.
Other gas sensing devices are shown in U.S. Patents to Ogg, U.S. Pat. No. 3,482,233; Chavis, U.S. Pat. Nos. 4,340,885; 4,119,950; Hayden, U.S. Pat. No. 3,789,231; Stetter et al., U.S. Pat. No. 4,384,925; Murphy, U.S. Pat. No. 5,576,739; Tanigawa, U.S. Pat. No. 3,978,476; and Dunham et al., U.S. Pat. No. 3,209,343.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome the aforesaid deficiencies in the prior art.
It is another object of the present invention to provide a unique arrangement of circuits and components to facilitate field installation of gas monitoring sensors.
It is a further object of the present invention to provide a system for gas monitoring in which sensors can be calibrated from a safe, remote location.
It is a further object of the present invention to provide a system for gas monitoring having an integrated field panel for connections from the sensor clusters to a central monitoring location.
According to the present invention, a complete and modular arrangement of wiring for remote sensors and monitoring stations is provided which comprises a communication box for managing large numbers of sensors throughout large buildings, mines, tunnels and other such facilities. The system of the present invention comprises long distance communications, remote calibration and regulator modules, and optional intrinsic safety barriers in one compact module. Also included are relays for controlling alarms and plant functions. The module can optionally house an AC/DC power supply with attendant backup batteries. A strobe and horn can be added, as well as essential field switches, for emergency stop and alarm reset.
In the system according to the present invention, remote gas sensors are located in a position where the gas of interest is most likely to be found. For gases which are heavier than air, such as propane, the sensors are located near the ground or the floor. For gases which are lighter than air, such as methane, carbon monoxide, or hydrogen, the sensors are located high in the facility to be monitored. For monitoring hazardous gases, intrinsic safety barriers are included in the system.
REFERENCES:
patent: 3090038 (1963-05-01), Klein et al.
patent: 3209343 (1965-09-01), Dunham et al.
patent: 3482233 (1969-12-01), Ogg
patent: 3789231 (1974-01-01), Hayden
patent: 3978476 (1976-08-01), Tanigawa
patent: 4067004 (1978-01-01), Gulbrantson
patent: 4119950 (1978-10-01), Redding
patent: 4340885 (1982-07-01), Chavis et al.
patent: 4384925 (1983-05-01), Stetter et al.
patent: 4555930 (1985-12-01), Leach et al.
patent: 5305639 (1994-04-01), Pontefract
patent: 5576739 (1996-11-01), Murphy
Browdy and Neimark
Lieu Julie
Rel-Tex
LandOfFree
Integrated field monitoring and communications systems does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Integrated field monitoring and communications systems, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Integrated field monitoring and communications systems will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2441952