| 摘要 |
Devices for backflushing the particulate mineral beds of iron filters, water softeners and other water conditioners normally include a vertical tube through which water flows downwardly to the bottom of the tube where the water is discharged through a distributor screen. The water then flows upwardly through the bed where particulate matter is cleaned from mineral. A second such device includes a pair of parallel tubes and a venturi orifice for drawing mineral into one of the tubes. An efficient device for ensuring uniform backwashing of particulate mineral bed includes an elongated tubular casing and a central, co-axial tube extending beyond the ends of the casing. The top of the casing is normally closed by a cap slidable on the tube, and maintained in position by a helical spring. By injecting water into a space between the cap and an inner sleeve on the tube, the cap is caused to move upwardly to open the top end of the casing. A valve normally closes the bottom end of the casing, but permits the flow of water upwardly into the tube during normal use. In order to backwash, the valve is closed by reversing the flow of the water. Such downward flow causes opening of the top end of the casing, followed by the outward flow of water against a sleeve diaphragm on the valve body to permit water to flow upwardly into the casing bottom where particulate mineral bed is drawn into venturi openings and moves upwardly out of the open top end of the casing. Upon completion of the backflushing operation, the flow of water is reversed, the spring returns the cap to the closed position, the diaphragm closes against the valve body, and the normal flow of water up the central tube is resumed. |
