Abstract:
An earthquake actuated automatic gas shutoff valve having a valve bottom portion with a generally horizontal floor having a ball seat and a valve seat surrounding a gas outlet passageway. A ball having an elastomeric outer surface is held in the ball seat and in the event of an earthquake, the ball is shaken out of the ball seat and rolls into the valve seat to stop the flow of gas. The ball can either be a solid elastomeric ball or a metal ball with an elastomeric outer coating.

Description:
BACKGROUND OF THE INVENTION 
     The field of the invention is earthquake actuated gas shutoff valves. There is a large variety of designs of such valves. One such valve is shown in U.S. Pat. No. 5,823,223 which has a ball held on a pedestal. This patent is a continuation in part of U.S. Pat. No. 5,603,345. During an earthquake the ball of the &#39;223 patent falls off of the pedestal and falls over a valve seat. The valve is reset externally by turning an arm which moves the ball off of the valve seat and back onto the pedestal. Another design is shown in U.S. Pat. No. 5,704,385 where a ferromagnetic ball rolls out of a depression and causes a valve member to move against a valve seat thereby blocking the flow of gas. In a different embodiment, the ball is held in a depression and rolls into a valve seat in the gas flow path. The ball is manipulated magnetically to reset the valve. 
     Another version of a ball which rolls out of a higher position to a lower position where it blocks a valve seat is shown in U.S. Pat. No. 5,603,345. Yet another version of a ball held in a depression which moves into a valve seat is shown in U.S. Pat. No. 5,052,429. Another version is shown in U.S. Pat. No. 4,889,150. Still another valve using a ball resting on a pedestal is shown in U.S. Pat. No. 4,715,394. A relatively simple design is shown in U.S. Pat. No. 3,747,616 where the ball is reset by a string attached to the ball. 
     One inherent disadvantage of using a steel ball is the damage the steel ball can do during shipping. Various approaches have been used to reduce this problem, some of which involve the addition of packing materials during shipping. Occasionally, during installation, the installer will forget to remove the packing materials. Also, many of the prior art valves do not have any means of determining when the valve is open or closed from the exterior of the valve. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an earthquake actuated automatic gas shutoff valve which can be shipped without the necessity of capturing the ball during shipping and which is equipped with means for determining whether the valve is open or closed from the exterior of the valve. 
     The present invention is for an earthquake actuated automatic gas shutoff valve which has a valve cover, a valve body and a valve bottom. The valve bottom has a generally horizontal floor with a ball seat formed in the floor. A valve seat surrounds a gas outlet passageway in the floor. An elastomeric ball is placed in the ball seat and during an earthquake the ball moves out of the ball seat and falls into the valve seat, and a moving arm is operated from outside the valve to move the ball from the valve seat back to the ball seat. Preferably, the valve includes a sight glass which shows whether or not the ball is in the valve seat or on the ball seat. The ball can be either a solid or hollow elastomeric ball or can have an elastomeric outer layer and a metal inner layer. The valve can also be equipped with a manual shutoff feature. In this way the user can easily turn off the flow of gas without the necessity of manipulating the large and often difficult to close shutoff valve in the main gas line. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of the earthquake actuated automatic gas shutoff valve of the present invention. 
     FIG. 2 is a top view of the valve with the cover removed. 
     FIG. 3 is a top view of the valve with the cover in place. 
     FIG. 4 is a front view of the valve of FIG.  1 . 
     FIG. 5 is an enlarged perspective view showing the ball removal apparatus of the valve of FIG.  1 . 
     FIG. 6 is an enlarged top view of the floor of the bottom of the valve of FIG.  1 . 
     FIG. 7 is a cross-sectional view taken along line  7 — 7  of FIG.  1 . 
     FIG. 8 is an enlarged side view of a first embodiment of a ball unseating apparatus of the valve of FIG.  1 . 
     FIG. 9 is an enlarged plan view of the ball seat of the valve of FIG.  1 . 
     FIG. 10 is a cross-sectional view of the ball seat taken along line  10 — 10  of FIG.  9 . 
     FIG. 11 is a cross-sectional view of a ball having a metal core and an elastomeric outer cover. 
     FIG. 12 is a bottom view of the top of the valve of FIG.  1 . 
     FIG. 13 is side view of an alternate configuration of a gas inlet portion of the valve of FIG.  1 . 
     FIG. 14 is a side view of an alternate embodiment of a ball removal assembly of the valve of FIG.  1 . 
     FIG. 15 is a side view of an alternate embodiment of the ball removal assembly of the valve of FIG.  1 . 
     FIG. 16 is a cross-sectional view of an elastomeric ball. 
     FIG. 17 is a cross-sectional view of a hollow elastomeric ball. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An earthquake actuated automatic gas shutoff valve is shown in FIG.  1  and has a valve body  1 , a cover  2  and a bottom  3 . Cover  2  has a hexagonal portion  2 ′ shown best in FIG. 3 of the drawings. Bottom  3  also has a hexagonal portion  3 ′ identical to hexagonal portion  2 ′. 
     An elastomeric ball  4  is shown on a ball seat  5  in FIG. 1 in which position gas may flow through the valve in the direction of arrows  20 . After an earthquake, the ball moves to a position shown in phantom view indicated by reference character  4 ′ in FIG. 1, where it rests in valve seat  13 , thereby shutting off the flow of gas through the valve. As will be discussed below, ball seat  5  has a drilled hole  6  below it. 
     As shown in FIG. 2, valve body  1  has a wall  18  which restricts the travel of the ball. An angled surface  19  of the wall  18  is shaped to assist in the deflection of the ball toward the valve seat  13 . The ball  4  is moved from the closed position indicated by reference character  4 ′ in FIG. 1 to an open position indicated by reference character  4  in FIG. 1 by the turning of reset shaft  8  shown in FIG.  4 . As shown best in FIG. 5, reset shaft  8  holds a pair of downwardly depending arms  9  which support a ball contact arm  10  which is rotatingly held in arm support members  11 . Reset shaft  8  is manipulated by a coin or screwdriver inserted in slot  12  shown best in FIG. 4 of the drawings. Reset shaft  8  is urged in a counter clockwise direction by spring  16  shown in FIG. 5 so that the ball contact arm will be retained in the position shown in FIG. 1 out of the way of the valve seat  13 . 
     A beneficial feature of the present design is the provision of means to manually close the valve even when there is no earthquake. This is accomplished by rotating shaft  31 , also supported by body  1  in FIG.  4 . Shaft  31  also extends out of body  1  and has a screwdriver or coin slot  32 . A pair of rods  33  shown best in FIG. 7 contact ball  4  and move it from its ball seat  5  into the position shown by reference character  4 ′ in FIG. 1 against valve seat  13 . Occasionally, the manual shutoff valve in the gas line (not shown) is corroded or difficult to turn and this provides an easy method of turning off the flow of gas without having to get a wrench to close the conventional gas shutoff valve. Shaft  31  can be readily turned with a coin, thereby permitting the shutting off of the valve in an emergency without the necessity of finding a wrench. A spring  34  shown in FIG. 1 retains rods  33  out of the way until the shaft  31  is turned. Reset shaft  8  and closing shaft  31  are, of course, provided with O-rings and roll pins to limit turning and axial motion, such features being conventional, they are not shown in the drawings, since they are not necessary for an understanding of the present invention. 
     Another feature of the valve as shown in FIG. 1 is the provision of a gas deflector  30  shown in top view in FIG.  12 . An inlet gas line (not shown) is threaded into the threaded opening  35  in cover  2 . This is the gas inlet path and gas flowing at a relatively high rate of flow from inlet  35  out of outlet  36  could theoretically be sufficient to pull a relative light elastomeric ball  4  from its ball seat and into the closed position in valve seat  13 . Gas deflector  30  directs the flow of gas away from ball  4  and causes sufficient turbulence so that the gas flow path does not tend to pull ball  4  out of ball seat  5 . 
     The preferred construction of ball seat is shown best in FIGS. 9 and 10 where the ball seat  5  can be seen to be a conical depression in bottom  3 . The depression has a diameter D. The diameter D of the ball seat determines the actuation G level at higher frequencies. The standard calls for the closing of the valve at a G level of over 0.4 G at 10 Hz compared to 0.15 G at 2.5 Hz. For the same G level the movement at 10 Hz is only {fraction (1/16)} that at 2.5 Hz. The diameter of the seat can be made large enough to contain the 10 Hz movement while allowing the lower frequencies to actuate. To meet the standard the diameter is preferably about 0.375″. The angle of the cone is preferably about 13°. Of course, the ball seat can be machined out and an insert added with a different angle and diameter for different actuation requirements. The hole  6  at the apex of ball seat  5  is useful for lightweight balls to provide repeatable actuation at higher frequencies. At 7.5 Hz and 10 Hz the ball is shaking back and forth and cannot escape the ball seat just below the actuation level. While a steel ball will keep reasonable contact with the seat, a lightweight elastomer begins to float on an air cushion causing the actuation level to vary. By adding hole  6  at the apex of the cone, as large as possible without interfering with the ball seat of the ball, the cushion of air is reduced dramatically and the ball stays in contact with the cone for constant actuation. 
     Another interesting advantage of the use of an elastomeric ball  4  is its ability to form a gas tight seal in seat  13  without the necessity of using an O-ring. The elastomeric ball under higher pressures tends to form a very tight seal and this could make it difficult to remove the ball from the seat if a conventional bar was used. For this reason, it has been found useful to provide a rotating ball contact arm  10 . As indicated in FIG. 8, as the elastomeric ball  4  starts to be moved out of valve seat  13 , it will move upwardly against the rotating ball contact arm  10 , since it will not tend to slide at its point of contact indicated by reference character  13  in FIG.  8 . Two actions assist in rolling the ball out of valve seat  13 . One is shown in FIG. 8 where the elastomeric ball is depressed and provides a small opening  36  which will permit the gas pressure to quickly become equalized on both sides of ball  4 , facilitating the removal of ball  4  from valve seat  13 . Several other structures will permit this same upward movement at the point of contact of ball  4  with arm  10 . In FIG. 14 a square bar  23  is held in a bar slot  24  in arm support member  11 . This permits the square bar  23  to move upwardly as the ball is urged out of valve seat  13  as shown in FIG.  14 . The term “elastomeric” as used herein is intended to mean a polymer which possesses rubber-like qualities, especially the ability to regain shape after deformation. 
     In FIG. 15, a hinged bar  25  is hingedly pinned at pin  26  to downwardly depending arm  9  so that it may rotate upwardly as indicated by the arrow in FIG.  15 . Any of these means will help to roll the ball out of the valve seat and greatly facilitates the removal of the ball as compared to an arm fixed to arms  9 . 
     Another interesting feature of the valve of the present invention is the provision of sight glass  37  shown best in FIG. 4 of the drawings. This permits a user to see the position of the ball through sight glass  37 . It may be positioned either as shown in FIG. 1 adjacent the ball positioned in ball seat  5 . Alternatively, it could be positioned adjacent the position of ball  4 ′ in FIG. 1, which would show the ball fixed in the closed position. This permits one to quickly see the ball position. Another feature which is able to make the operation of the valve of the present invention more intuitive is to utilize a colored elastomeric ball in conjunction with sight glass  37 . For instance, when the sight glass is positioned as shown in FIG. 1 of the drawings adjacent the ball seat  5 , and the ball is made green, the user is naturally led to believe that the gas flow path is on. Conversely, if the ball were made from a red polymer and the sight glass was positioned over the ball seat, one looking through the sight glass and seeing a red ball would tend to believe that the valve is off and the gas flow is stopped. 
     Another beneficial feature can be added by counter sinking shafts  31  and  8 . A conical depression  31 ′ and a conical depression or recess  8 ′ permits these shafts  31  and  8  not to extend outwardly from the valve body so that they are less likely to be damaged during shipment and construction. It is not uncommon for a workman to drop a hammer or brick and if the shafts extend a significant distance away from the body, the likelihood of damage to the valve is increased. By recessing these shafts, a valve results which is more resistent to rough handling. 
     The shape of the wall  18  is designed to provide several actions. First, the wall and the rods  33  are positioned so that the center of gravity of the ball is always over ball seat  5  once the ball has been pushed back away from valve seat  13 . In this way, after resetting, the ball will always fall back into ball seat  5 . A portion of wall  18  is angled as indicated by reference character  19 , which helps in the event of cross-axis shaking (up and down as viewed in FIG.  2 ). The ball will not simply bounce back and forth over the ball seat  5  but instead, will ricochet off angled portion  19  toward valve seat  13 . 
     Construction of the valve is simplified by providing that the body, cover and bottom are in three separate pieces as shown in FIG.  1 . This three-piece configuration is not essential, however, but it does permit the extrusion of the valve body. In order to secure the body pieces into one strong unit, four special screws  27  (see FIG. 13) are used which act as dowel pins and permit the turning of the valve as a solid block. 
     A valve cover  2  is shown in FIG. 13 having an L-shaped configuration. It is, of course, also possible that such configuration could be formed in bottom  3 . The construction of the ball is preferably a solid elastomer as indicated by ball  38  in FIG.  16 . Alternatively, it can be an elastomeric ball with a hollow center, such as shown in FIG.  17  and indicated by reference character  39 . The ball shown in FIG. 11 has a metal core  14  and an outer elastomer  15  which, of course, provides a heavier ball and permits the use of magnetic manipulation if desired. Furthermore, if the valve were subjected to a temperature high enough to disintegrate the elastomer, the steel portion is still large enough to shut off the gas flow. 
     Elastomeric balls can change hardness with temperature and it has been found that by the use of a fluorosilicone elastomer, a very wide range of temperatures is permitted without any degradation of the elastomeric properties of the ball. It is, of course, possible to use a solid hard plastic ball or a metal ball in the valve of the present invention, but the sealing features and the damage-free features would be adversely affected. 
     The present embodiments of this invention are thus to be considered in all respects as illustrative and not restrictive; the scope of the invention being indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.