| 摘要 |
<p>STATIC METERING PUMP A static metering pump includes a pair of tanks, electrically operated inlet and outlet valves, liquid level sensors and controls which permit the alternate filling of a first of the tanks while permitting the discharging of liquid from a second of the tanks and then permitting the discharging of liquid from the first tank while filling the second tank. The cycle of filling and discharging of the tanks is repeated until a preselected volume of liquid is dispensed with precise metering. The two tanks are adapted to dispense the same volume of liquid in normal operation. Where the total volume of dispensed liquid called for includes a fraction of the normal volume of the tank, one of the tanks is provided with a fractional liquid level sensor which may be preset to fill this tank initially to the fractional volume and to commence the metering operation by the discharge of this tank.</p> |
