| 摘要 |
An apparatus for maintaining a predetermined liquid level within a tank while effecting the continuous addition and removal of liquid within the tank. The apparatus is provided with a housing that mounts directly on a side wall of the tank with the housing extending on both sides of the wall, so that it is partially inside and partially outside the tank. The housing has a first passageway which receives fresh liquid from a pressurized supply and introduces a portion of the fresh liquid into the tank. The remainder of the fresh liquid is provided to a second passageway which is connected between the first passageway and a drain. The second passageway has a constriction near its inlet, which accelerates liquid flowing through it and injects the liquid into the second passageway at a high speed. This produces a region of low pressure in the second passageway. A third passageway is connected to the region of low pressure and it is coupled to the water in the tank. By this arrangement, the low pressure is coupled to the third passageway, and is expelled to the drain. In one embodiment, the apparatus includes a mechanism for fail-safe operation in the event of excessive supply pressure build up.
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