Abstract:
A bracket type biogas storage cover includes a cover with an exhaust vent, characterized in that there are at least two brackets which are used to fix the cover to a biogas digester&#39;s opening on the lower edge of the cover.

Description:
BACKGROUND OF THE PRESENT INVENTION 
     1. Field of Invention 
     The present invention relates to a movable gas storage cover of a hydraulic biogas fermentation device, and particularly to a bracket type biogas gas storage cover. 
     2. Description of Related Arts 
     The China patent number ZL03201184.3 “Foldable Biogas Digester Cover” disclosed a removable gas storage cover for biogas digester, wherein three reinforcing beams are provided on top of the removable cover. Removable connectors are mounted on the reinforcing beans. The removable connectors can be plugged into the inner edge of the opening of the biogas digester so that the removable cover can be fixed inside the opening of the biogas digester. Because the removable cover is fixed via the removable connectors, the removable cannot be upwardly floated at the time when the biogas is stored in the removable cover. Practically, such structural configuration is useful in practice but still have some disadvantages. The removable cover is fastened to the opening of the gas storage by the three reinforcing beams to prevent the removable cover from floating upward. In other words, the three reinforcing beams exert the downward force to push down the removable cover from the top thereof. However, when the removable cover is exerted by the gas pressure inside the biogas digester, the removable cover is deformed especially with the resistance from the reinforcing beams. Therefore, the removable cover must be configured to have high stiffness and strength for anti-deformation. This will increase the production cost and limit the service life span of the removable cover. 
     SUMMARY OF THE PRESENT INVENTION 
     According to the disadvantage of the conventional hydraulic biogas digesters, the main object of the present invention is to provide a bracket gas storage cover which can largely reduce the requirement of the stiffness and strength for preventing the deformation, reduce the fabrication cost, and increase the service life span. 
     Accordingly, in order to accomplish the above objects, the present invention provides a bracket type biogas gas-storage cover, comprising a cover having an air vent, a reinforcing ring provided at an opening edge, and at least two brackets spacedly provided the reinforcing ring for affixing the opening edge of the cover at the opening of the biogas digester. 
     Preferably, there are three brackets evenly provided at the opening edge of the cover. 
     The principle of present invention is that the cover is mounted to the biogas digester by coupling the lower opening edge of the cover with the opening of the biogas digester. Unlike the conventional structure of the cover by coupling the top of the cover with the biogas digester, the stress points of the cover shift to the lower opening edge thereof. In other words, the pressure will not be exerted at the top of the cover. Therefore, the cover can retain its hemispherical shape for preventing the cover from being deformed by the pressure. Accordingly, the cover requires having a predetermined stiffness and strength at the opening edge to couple with the opening of the biogas digester. Therefore, there is no particular physical configuration of the cover to maintain a predetermined stiffness thereof. In addition, the strength of the cover can be relatively low. In other words, the cover can even be made of soft material. 
     Accordingly, the force distribution of the cover is more efficient. The stiffness and strength requirement of the cover can be substantially lowered. The production cost of the cover can be significantly reduced. In addition, the life span of the cover can be greatly extended. 
     The bracket biogas gas-storage cover of the present invention is efficient, convenient and practical. It is easy to mount the cover within the opening of the biogas digester by using the plugs and the brackets. The present invention not only provides all the functions of the conventional gas cover to satisfy the requirements of the normal use, but also overcomes the drawbacks of the conventional gas cover including the strict requirements of the material, high production cost and short life span. 
     These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is the perspective view of a bracket type biogas storage cover according to a preferred embodiment of the present invention. 
         FIG. 2  is an exploded schematic view of the bracket type biogas storage cover according to the above preferred embodiment of the present invention. 
         FIG. 3  is the schematic diagram of the bracket of the bracket type biogas storage cover according to the above preferred embodiment of the present invention. 
         FIG. 4  illustrates an alternative mode of the bracket of the bracket type biogas storage cover according to the above preferred embodiment of the present invention. 
         FIG. 5  is a partially enlarged schematic view of the bracket type biogas storage cover according to the above preferred embodiment of the present invention. 
         FIG. 6  is the schematic diagram of the bracket type biogas storage cover installed in a biogas digester according to the above preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 and 2  of the drawings, a bracket type biogas storage cover for a biogas digester according to a preferred embodiment is illustrate, wherein the biogas storage cover, which is a biogas digester cover, comprises a cover  1  having an air vent  12  and a plurality of brackets  2 . The cover  1  has a hemisphere shape. A reinforcing ring  11  is provided at an opening edge of the cover, wherein the air vent  12  is provided on top of the cover  1 . Accordingly, there are three brackets  2  spacedly provided at the reinforcing ring  11  for coupling the opening edge of the cover  1  with the opening of the biogas digester. 
     As shown in  FIG. 3 , each of the brackets  2  comprises a supporting frame  22  having a triangular shape, and a locking sleeve  21  provided at the vertex of the supporting frame  22  for a pin locker  3  passing through the locking sleeve  21 . The supporting frame  22  has a curved base  221  wherein a curvature of the curved base  221  matches with a curvature of the reinforcing ring  11 . The supporting frame  22  further has a plurality of mounting holes  223  spacedly formed at the curved base  221  for the curved base  221  of the supporting frame  22  mounting at the reinforcing ring  11  via bolts and nuts. 
       FIG. 4  illustrates an alternative mode of the bracket  2 , wherein the locking sleeve  21  is connected to the vertex of the supporting frame  22  via a hinge. Two hypotenuse edge frames  222  of the supporting frame  22  are also connected to the curved base  221  via two hinges respectively. Through the hinges, the locking sleeve  21  is pivotally coupled with the supporting frame  22  while the hypotenuse edge frames  222  are pivotally coupled with the curved base  221 . Accordingly, such pivotal configuration of the supporting frame  22  facilitates the installation of the cover  1  to the biogas digester. 
     Accordingly, the locking sleeve  21  has a Ω-shaped horseshoe structure and has two fringes  211  extended from an opening of the locking sleeve  21 , wherein a screw hole is provided at each of the fringes  211  for pivotally connecting to the supporting frame  22  via the corresponding hinge. Each of the hypotenuse edge frames  222  has a S-shaped structure. A screw hole is provided at each end of the hypotenuse edge frame  222 . The supporting frame  22  further has two U-shaped connectors  224  spacedly provided at the curved base  221 , wherein each of the U-shaped connectors  224  also has a screw hole formed thereon. Each of the hypotenuse edge frames  222  is pivotally coupled between the locking sleeve  21  and the curved base  221  by coupling the two ends of the hypotenuse edge frame  222  with the fringe  211  and the respective U-shaped connector to align the screw holes with each other, such that the screws are used as a connecting element to pivotally connect the hypotenuse edge frame  222  between the locking sleeve  21  and the curved base  221 . Accordingly, the advantage of the pivotal configuration of the bracket is that the angle of the locking sleeve  21  with respect to the supporting frame  22  can be selectively adjusted. In addition, the angle of the hypotenuse edge frame  222  with respect to the curved base  221  can also be selectively adjusted. Therefore, the bracket type biogas gas-storage cover of the present invention can be easily mounted at the opening of the biogas digester. 
     In order to release the pressure inside the biogas digester, the cover  1  further has a vent hole  13  formed at a top side thereof and comprises a sealing cap  14  sealed and mounted at the vent hole  13 , as shown in  FIG. 5 . The vent hole  13  has an inner threaded portion  131  formed at an inner edge wall thereof and a shoulder edge portion  132  to support a sealing ring  15  thereat. The sealing cap  14  comprises an outer threaded portion  141  formed at a bottom edge to engage with the inner threaded portion  131  of the vent hole  13 , wherein the sealing ring  15  is sealed between the bottom edge of the sealing cap  14  and the shoulder edge portion  132  of the vent hole  13 . The air vent  12  is provided at the top end of the sealing cap  14 . 
     As shown in  FIG. 6 , the bracket type biogas storage cover of the present invention is mounted at the opening of the biogas digester. Accordingly, a plurality of retention holes are spacedly formed, preferably by drilling, at an inner wall of the opening  4  of the concrete biogas digester with respect to the location of the locking sleeves  21  of the biogas storage cover. Then, when the cover  1  is coupled within the opening of the biogas digester to align the locking sleeves  21  with the retention holes respectively, pin lockers  3  are slidably extended through the locking sleeves  21  to engage with the retention holes respectively, so as to retain the cover  1  within the inner wall of the opening  4  of the biogas digester. Preferably, three pin lockers  3  are used for locking up the cover  1  within the inner wall of the opening  4  of the biogas digester. 
     One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. 
     It will thus be seen that the objects of the present invention have been fully and effectively accomplished. It embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.