| 摘要 |
A positive displacement gas meter includes a two-piece composite center casting. The first piece is a center chamber casting which has a lower cylindrical wall partially defining the center chamber and an upper manifold portion defining passages to front and rear chambers defined by diaphragms and front and rear covers secured to the center chamber casting. The second piece comprises a valve chamber manifold casting which mounts to the top of the center chamber casting and defines openings registering with the openings to the front and rear chambers. The valve chamber manifold also partially defines a center chamber and defines an opening thereto, and further at least partially defines an exhaust passage having a collection end adjacent the openings to the chambers and leading to an outlet end. A valve seat having a sliding valve cover is mounted to the valve chamber manifold casting, and a top casting fits thereover and is secured to the valve chamber manifold casting. The valve chamber manifold casting further defines an integral depending support bracket for mounting a center shaft gas meter, the center shaft being rotated by a linkage to the diaphragms and in turn revolving the valve cover on the valve seat. A meter readout assembly is also provided.
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