Earthquake utilities cut-off control system
BACKGROUND OF THE INVENTION 
     Seismic disturbance detectors are known as well as systems which combine such detectors with utility control arrangements in order to provide for automatic cut off of gas, water and electric utilities to a building in the event of earthquakes of a predetermined magnitude. Examples of such devices may be found in the following U.S. Pat. Nos.: 3,714,456, 4,214,238, 4,390,922, 4,408,196 and 4,528,559. 
     None of these devices have achieved wide spread acceptance for a variety of reasons. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     An object of this invention is to an automatic shut-off system which is compact, easy to install and inexpensive to manufacture. 
     A further object of this invention is to provide a system which is pre-packaged. 
     Yet another object of this invention is to provide a system having two compartments for ease in access, separating the primary electrical components from the utility cut-off control devices. 
     The present invention embodies an arrangement of known devices so packaged as to satisfy all U.L.&#39;s requirements and those of the National Electrical Manufacturers Association. The entire system constitutes a fail safe arrangement wherein electrical signals generated by a seismic detector are employed in combination with an uninterruptible power supply system to automatically shut off all utilities to a building. The power supply and seismic detection equipment together with a circuit breaker for terminating electrical service to the building are housed separately from the gas and water lines and cut off valves for each. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a block diagram of the basic components of the present system; 
     FIG. 2 is a schematic wiring diagram; and 
     FIG. 3 shows the apparatus of the present invention housed in separate containers. 
    
    
     DETAILED DESCRIPTION 
     Referring first to FIG. 1, a central unit is indicated as being supplied with electrical power from an uninterruptible power system. The latter is a well known article of commerce as for example, one manufactured by Square D Company. As indicated in this Figure, the central unit includes normally closed switches supplying energy from the uninterruptible power system to both the natural gas automatic shut off valve and the water automatic shut off valve. So long as these switches remain closed, the automatic shut off valves are open and service to the building continues. The control for cut off of electrical service is the reverse in that the switch supplying current thereto from the uninterruptible system is normally open. In response to a signal from the seismic detector, the condition of the switches as shown in FIG. 1 is reversed which automatically cuts off all utilities service to the building. At the same time, an audible and/or visual warning device may also be activated. 
     FIG. 2 is simply a schematic diagram conforming to the parts arrangement of FIG. 1. The presence of a signal from the seismic detector of FIG. 1 will close the switch 10 of the seismic trigger to energize the control relay 12. The latter may have four sets of contacts 14, 16, 18 and 20, the first two of which are normally closed and the latter two are normally open. Energization of relay 12, therefore, will open the contacts 14 and 16 and close the contacts 18 and 20. This, in turn, is effective to deenergize coils 22 and 24 while energizing coil 26 and the audio visual devices labeled as siren and light. Coils 22 and 24 control the cut off valves for the gas and water lines which are automatically closed as soon as these coils are deenergized. 
     FIG. 3 shows a preferred arrangement of the parts of FIG. 1 as they would be housed in pre-packaged units for installation at any given building. Basically, the packaging involves a pair of weatherproof enclosures 30 and 32 having secured access doors (not shown). The upper enclosure 30 houses closed piping loops 34 and 36 for gas and water respectively. Each loop includes a solenoid operated cut off valve 38 and 40. Valves 38 and 40 are electrically operated and, once closed, may be manually reopened only after the electrical power is reconnected to the valves. In addition, manually operated cut off valves 42 and 44 are provided in each closed loop to by-pass the automatic valves 38 and 40. The operating means for the manual valves is accessible from the exterior of the cabinet 30. The closed loops 34 and 36 each terminate at the closure wall in means affording connection to the piping within the building and the supply main. 
     The lower enclosure 32 houses the other elements of the system including the seismic detector 46, the uninterruptible power supply 48, the electrical circuit breaker 50 and the central unit 52. An audible warning device such as a siren may also be included as indicated at 54 and a visible warning means may be positioned exteriorly of either cabinet as indicated for example, at 56. 
     The seismic detector 46 must be rigidly mounted on a base shown at 58. This is a concrete slab of approximately 18 inches thickness, 12 inches of which is below ground. The detector is rigidly bolted to the slab by bolts 60 and 61. 
     While the containers 30 and 32 are shown in FIG. 3 as immediately adjacent one another, this is not essential and they may be remote from each other. Relative positioning of the two will be dictated in each instance by the location of the utility mains with respect to the building. 
     While a preferred embodiment of the present invention is herein shown and described, applicants claim the benefit of a full range of equivalents within the scope of the appended claims.