| 摘要 |
A device for backwashing a particulate mineral bed in a water conditioner includes a tubular casing; a tube co-axial with and extending through the casing beyond the ends thereof; a cap slidable on the tube for movement between a closed position on the open top end of the casing and an open position spaced apart from the top end of the casing; a spring biasing the cap to the closed position; an opening in the tube for discharging water into the cap to cause the latter to move away from the casing to the open position; a first valve including a valve body closing the bottom end of the casing; a first passage in the valve body in fluid communication with the bottom end of the tube, the first passage being normally open to the flow of water upwardly from the bed of particulate material into the tube; a ball in the body for closing the first passage when the flow of water is reversed in the tube; a second passage in the top of the body communicating with the first passage; a second valve normally closing the second passage for discharging water from the valve body when the flow of water is reversed in the tube; and a hood on the tube above the valve body defining a venturi opening in the bottom end of the casing permitting the flow of particulate material into the casing. In order to prevent compaction or cementing of the bottom of the bed, a hole extends through the ball in the first valve.
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