Abstract: A metering pump is joined to the stepping motor, includes an eccentric mechanism converting a revolving motion of the stepping motor into a reciprocating motion of a plunger, and makes a constant liquid delivery by sucking and discharging an anesthetic agent through variations in the cubic volume of a cylinder caused by the reciprocating motion of the plunger. The control section: calculates a suction and discharge cycle T of the metering pump on the basis of a set anesthetic-gas concentration and a fresh-gas flow rate; sets a discharge period T2 of the cycle T to be longer than a suction period T1 of the cycle T; and controls the revolution speed of the stepping motor so that the travelling speed of the plunger is kept constant during the discharge period T2.

Abstract: An anesthetic tank includes an insertion mouth for inserting an injection adapter of an anesthetic container, and a storage portion communicating with the insertion mouth. A volatile anesthetic inside of the anesthetic container is injected into the storage portion. An identifying member is arranged on the outside of the insertion mouth and is rotatable around the center axis of the insertion mouth. The identifying member has key groove formed in the internal surface of an insertion hole for inserting the injection adapter. The key groove are used for identifying the type of the volatile anesthetic in collaboration with keys formed in the injection adapter. A cover member has an opening formed in the position facing the insertion mouth and the insertion hole and presses the peripheral part of the identifying member.

Abstract: [Problems] To provide a driving method for a metering pump, a driving apparatus for a metering pump, a vaporizer and an anesthesia apparatus which are capable of suppressing a pulsation in the metering pump, and lowering the costs and reducing the sizes of the vaporizer and the anesthesia apparatus. [Means for solving the Problems] A metering pump 16 is joined to the stepping motor 15, includes an eccentric mechanism converting a revolving motion of the stepping motor 15 into a reciprocating motion of a plunger 16A, and makes a constant liquid delivery by sucking and discharging an anesthetic agent through variations in the cubic volume of a cylinder 16D caused by the reciprocating motion of the plunger 16A.