Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2000-04-19
2001-10-02
Tweel, John (Department: 2736)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S572800, C340S539230, C340S573400
Reexamination Certificate
active
06297735
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a security system including a cable which can be placed on a valve or switch handle to immobilize the same, a lock capable of retaining the cable, and a communications device which reports status of the lock to a remote monitoring station. The principal application of the invention is that of industrial safety in large facilities which handle piping systems having valves and electrical systems having switches. Oil refineries and other large scale fluid handling facilities, factories, large institutions, commercial and industrial facilities, and other facilities which require occasional shut down of piping systems and electrical power can benefit from the invention. The invention finds further utility in the field of security wherein unstaffed gates, ramps, doors, elevators, and similar transport devices must be locked and monitored remotely.
2. Description of the Prior Art
Large facilities having valves, switches, compactors, and other large scale material and energy handling systems require periodic maintenance. Maintenance typically requires that at least part of the material and energy handling systems be shut down to enable personnel to conduct necessary maintenance operations. In large scale piping systems, such as in oil refineries and chemical plants, manual valves are frequently employed to obstruct flow in piping. Such valves typically have handles which are rotated into the “closed” position. Electrical switches, such as safety switches, motor starters, circuit breakers, and custom control panels are similarly ordinarily provided with handles to shut off power.
Personnel charged with performing maintenance close valves and shut off power, where appropriate, and then undertake maintenance operations. In large scale facilities, the site of the actual work is frequently remote from the valves and electrical controllers which have been turned off. There exists a considerable hazard that someone not involved with the maintenance operation will come upon a valve, switch, or other controller, and restore the associated equipment to operative status.
This has potentially catastrophic consequences. Unexpected starting of even a single piece of equipment can cause severe injuries to a person who may have a limb in the path of moving or rotating parts. In the example of oil refineries and chemical plants, unexpected flow of combustible fluids can result in fires and explosions. Power turbines, pumps, and other rotating equipment, boilers, pressure vessel and tank closures, conveyors, hoists, and other equipment may be shut off with only ordinary controls, and thus become potentially sources of hazards should they suddenly be rendered operative. Obviously, the field of industrial safety requires safety procedures to prevent such occurrences.
Electrical switches such as safety disconnect switches and circuit breakers typically have provision for accepting padlocks enabling the switch to be locked in the “off” position. In the event that someone cuts through the shackle of the padlock, there is no way to annunciate the consequent change in condition to either personnel engaged in maintenance operations or to a central authority charged with oversight of operations.
The prior art has suggested security devices which detect unauthorized actions. U.S. Pat. No. 5,657,003, issued to Alfredo Fuentes on Aug. 12, 1997, describes a camera and computer based monitoring system which monitors a building wall. Should the wall undergo displacement of any type, images recorded by the camera are compared to data stored in the memory of the computer. Determination of a discrepancy triggers an alarm. By contrast, the present invention engages the object being monitored by direct contact with a cable, preventing the object from being moved to a predetermined position. The present invention further transmits an alarm signal should the object be freed from engagement. The cable is connected to its base apparatus at two ends. There is no corresponding structure in the device of Fuentes.
A bicycle lock is described in U.S. Pat. No. 4,663,611, issued to Chris W. Humphrey on May 5, 1987. The lock has an integral audible alarm which sounds if someone disables the lock. By contrast, the present invention sends a signal to a remote monitoring station to generate an alarm, rather than sounding an audible alarm. The present invention utilizes a locking cable as part of the electrical circuitry of the alarm. There is no corresponding structure in Humphrey.
A position signaling apparatus is shown in U.S. Pat. No. 5,617,072, issued to Dennis D. McNeal on Apr. 1, 1997. McNeal's apparatus comprises a sensing arm which projects from a motor vehicle. Unlike the present invention, the arm does not engage and immobilize an external object. Also, the arm does not connect to the apparatus at two points, as does a corresponding cable in the present invention.
U.S. Pat. No. 3,303,457, issued to Jan Assar Åkesson on Feb. 7, 1967, sets forth a position sensor for sensing control rods of a nuclear reactor. There is no structure which engages and limits motion of the rods in the device of Åkesson. By contrast, the present invention has a cable which engages and limits motion of a moving component of an environmental object.
U.S. Pat. No. 2,685,685, issued to Carl M. Lathrop on Aug. 3, 1954, describes a sensor and alarm for a pipeline pig. There is no structure which engages and limits motion of the pig in the device of Lathrop. By contrast, the present invention has a cable which engages and limits motion of a moving component of an environmental object.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
SUMMARY OF THE INVENTION
The present invention sets forth a combined locking and signaling device suitable for immobilizing manual controls of valves, switches, and other objects which may be engaged by a flexible cable. The device includes a housing, a cable which projects from the housing at its proximal end and removably engages the housing at its distal end, an integral signaling device, and electrical circuitry including a battery. The locking and signaling device is ideally suited for universal application to all objects which are so constructed that a flexible cable may be interengaged with elements of the objects. Illustratively, the cable may be passed through a hand wheel of a valve such that the wheel may be effectively tied down and thus constrained against being opened. The same device is equally applicable in immobilizing a handle of a circuit breaker, safety disconnect switch, or other electrical controller adapted to receive a padlock. Still other devices, such as gates, ramps, elevators, and other structures having openings which can receive the cable of the novel device are susceptible to being immobilized by engagement with the cable, which is then tied to suitable anchorage.
The novel device includes signaling apparatus. Although it may be hardwired both to derive power and to pass signals, it preferably contains a battery and a radio frequency transmitter or other transmitter of energy signals. In the latter form, it is independent of connection, and is portable and readily installed. Signals are generated both periodically to advise that the locking device remains in the locked condition, and also if the lock should be opened or the cable cut. In addition to signals transmitted to a remote monitoring station, the device has an alarm light to advise that the lock is in the locked condition. This feature warns those not directly involved with the maintenance operation that there is a reason that the affected valve, switch, or other equipment must remain inoperative.
The novel device may be employed in any number, each signaling a remote monitoring station which enables a single person to oversee a large facility which may require many such locking and signaling devices. This answers an unsatisfied need in large scale indu
Siemens Patent Services LC
Tweel John
LandOfFree
Locked shut down with remote monitoring of large equipment does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Locked shut down with remote monitoring of large equipment, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Locked shut down with remote monitoring of large equipment will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2562668