| 摘要 |
Liquid dispensing apparatus comprises a T-tube (9) of which the limb tube serves as a closed reservoir (8) for liquid, with an air space above. Liquid is pumped by a peristaltic pump (A) through a tube (6) and one arm of the T-tube into the reservoir until a level detector (D) responds to the liquid level in the reservoir reaching a datum level whereupon it renders the pump (A) inoperative. A further peristaltic pump (B) then starts to pump liquid from the reservoir out of the other arm of the T-tube and through tubes 13 and 15 to an infusion needle in a patient's body. When the liquid level in the reservoir reaches a predeterined lower level detected by another detector (E), the second pump (B) is rendered inoperative and the cycle is then repeated starting with operation of the first pump (A). The use of a peristaltic pump as the second pump (B) enables the liquid delivery pressure at the needle to be held just above the minimum necessary for infusion. Also, any air bubbles in the reservoir will generally migrate to the air space. Conveniently, the tube assembly comprising the parts 6, 9, and 13 constitutes a disposable assembly which is very cheap to manufacture.
|
