| 摘要 |
<p>A supply unit 1 is provided for maintaining a desired level of a viscous liquid in a supply tank 2. The liquid is supplied through an inlet passageway 5 down to a horizontal portion 8 and then to a vertical portion 9 communicating with one side of a valve piston 11. When the tank 2 is full of a liquid, this liquid will be drawn up through a passageway 14 in a body 6 by a gear pump 15 which pumps the liquid through a supply line 18 to act on the other face of the piston 11. When the level of liquid within the supply tank 2 falls so that it cannot be drawn up through the passageway 14, the pressure on the upper face of the piston 11 will be relieved and the inlet pressure of the liquid in the inlet passageway 5 will then cause the piston valve 11 to open to allow the liquid to pass through an outlet passageway 13 leading into the supply tank 2.</p> |
