1. Advantages of cast iron valves The flow resistance is small. The inner medium passage of the valve body is straight through, the medium flows in a straight line, and the flow resistance is small. 2. It is more labor-saving when opening and closing. Compared with the shut-off valve, the direction of movement of the shutter is perpendicular to the direction of flow of the medium, whether it is open or closed. 3, high height, long opening and closing time. The opening and closing stroke of the shutter is large, and the drop is performed by the screw. 4. The water hammer phenomenon is not easy to produce. The reason is that the shutdown time is long.
Artworks are the crystallization of artists' intellectual labor. As a special commodity, it circulates in the art market. Like other commodities, it also has the basic attributes of ordinary commodities: use value and value; The difference is that the use value of works of art is embodied in the spiritual level rather than the material level. It aims to meet people's aesthetic and spiritual needs. Therefore, the use value of artworks is greatly affected by subjective factors.
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