Driving method for metering pump, driving apparatus for metering pump, vaporizer, and anesthesia apparatus

A driving apparatus for a metering pump, comprising:

• a motor;
• a control section controlling the revolution of the motor;
• and
• a metering pump joined to the motor, the metering pump including an eccentric mechanism converting a revolving motion of the motor into a reciprocating motion of a plunger of the metering pump, and making a constant liquid delivery by sucking and discharging a liquid through variations in the cubic volume of a cylinder of the metering pump caused by the reciprocating motion of the plunger,
• wherein the control section sets a discharge period of the metering pump to be longer than a suction period of the metering pump, and controls the revolution speed of the motor so that the travelling speed of the plunger is kept constant during the discharge period.

A vaporizer, comprising:

• a motor;
• a control section controlling the revolution of the motor;
• a metering pump joined to the motor, the metering pump including an eccentric mechanism converting a revolving motion of the motor into a reciprocating motion of a plunger of the metering pump, and making a constant liquid delivery by sucking and discharging a liquid through variations in the cubic volume of a cylinder of the metering pump caused by the reciprocating motion of the plunger;
• a gas pipe line transferring a fresh gas;
• and
• a flow path connected to the gas pipe line, the flow path delivering and vaporizing the liquid discharged from the metering pump and supplying the liquid to the gas pipe line, in which the vaporizer leads out a mixed gas of the fresh gas and the vaporized liquid gas,
• wherein the control section calculates a suction and discharge cycle of the metering pump on the basis of a set concentration of the mixed gas and a set flow rate of the fresh gas, sets a discharge period of the cycle to be longer than a suction period of the cycle, and controls the revolution speed of the motor so that the travelling speed of the plunger is kept constant during the discharge period.