[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. The control section 12: calculates a suction and discharge cycle T of the metering pump 16 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 15 so that the travelling speed of the plunger 16A is kept constant during the discharge period T2.

A liquid material ejection device in which a plunger is efficiently accelerated. The device includes a liquid chamber communicating with an ejection port and being supplied with a liquid material, a plunger including a tip portion having a smaller diameter than the liquid chamber and is moved in the liquid chamber, an elastic member urging the plunger upward, an arm disposed in a state extending in a substantially horizontal direction, an arm driver serving as a driving source to operate the arm, and a base member on which the arm driver is disposed. The device further includes a rocking mechanism unit connected to the arm driver and rockingly supporting the arm, the arm driver includes a plurality of actuators, the arm includes a pressing portion pressing the plunger downward, the plunger is pressed by the pressing portion, and the plunger is linearly reciprocated with rocking motion of the arm.

A liquid material ejection device in which a plunger is efficiently accelerated. The device includes a liquid chamber communicating with an ejection port and being supplied with a liquid material, a plunger including a tip portion having a smaller diameter than the liquid chamber and is moved in the liquid chamber, an elastic member urging the plunger upward, an arm disposed in a state extending in a substantially horizontal direction, an arm driver serving as a driving source to operate the arm, and a base member on which the arm driver is disposed. The device further includes a rocking mechanism unit connected to the arm driver and rockingly supporting the arm, the arm driver includes a plurality of actuators, the arm includes a pressing portion pressing the plunger downward, the plunger is pressed by the pressing portion, and the plunger is linearly reciprocated with rocking motion of the arm.

A pump is provided that includes a tube 1, tube rotors 21A, 21B, and 21C in contact with the tube 1, a case 3 containing the tube 1 and tube rotors 21A, 21B, and 21C, and a drive apparatus 10 that rotates the tube rotors 21A, 21B, and 21C from outside the case 3 without contacting the tube rotors 21A, 21B, and 21C.

A piezoelectric element driving circuit includes a boosting circuit, a driving circuit, a waveform shaping circuit, and a computing circuit. The driving circuit includes a differential amplifier circuit with an LPF, an amplifier circuit with a BPF, an inverter, a resistor, and a comparator. The driving circuit applies a driving signal to a piezoelectric element of a piezoelectric pump. The waveform shaping circuit extracts a voltage signal from the driving circuit. On the basis of the voltage signal, the waveform shaping circuit and the computing circuit determine a voltage value corresponding to driving current flowing through the piezoelectric element. The computing circuit outputs a control signal to the boosting circuit on the basis of the voltage value. The boosting circuit sets the value of a DC supply voltage on the basis of the control signal, and outputs the DC supply voltage.

A piezoelectric element driving circuit includes a boosting circuit, a driving circuit, a waveform shaping circuit, and a computing circuit. The driving circuit includes a differential amplifier circuit with an LPF, an amplifier circuit with a BPF, an inverter, a resistor, and a comparator. The driving circuit applies a driving signal to a piezoelectric element of a piezoelectric pump. The waveform shaping circuit extracts a voltage signal from the driving circuit. On the basis of the voltage signal, the waveform shaping circuit and the computing circuit determine a voltage value corresponding to driving current flowing through the piezoelectric element. The computing circuit outputs a control signal to the boosting circuit on the basis of the voltage value. The boosting circuit sets the value of a DC supply voltage on the basis of the control signal, and outputs the DC supply voltage.

End element for the stator of an electric motor of a hermetically sealed refrigerant compressor including at least one isolating element, having a ring-like core, to cover an axial end portion of the stator and to isolate a stator core and stator windings. The end element includes several spring holders extending radially outside the isolating element, each spring holder being adapted to hold a spring for supporting the electric motor in a housing of the hermetically sealed refrigerant compressor. The spring holders are oriented parallel to the axis of the isolating element and an insertion part of each spring holder extends in a first axial direction beyond the neighboring area of the isolating element. The spring holders and the isolating element are integral parts of the end element. The spring holders are tiltable so that an extended part of a spring holder tilts radially inwards.

An apparatus is described which includes at least one reactor, at least one linear piston pump, the or each piston pump including a tube, a piston and an arm coupled to the piston, the or each piston pump arranged to inject feedstock to a respective reactor, a beam or plate coupled to the arm(s) of the piston pump(s) configured to linearly drive the piston(s) and a linear actuator for driving the beam or plate. The piston pump has a volume of at least 50 milliliters and an output port having a diameter of at least 5 mm.

A piezoelectric element driving circuit includes a boosting circuit, a driving circuit, a waveform shaping circuit, and a computing circuit. The driving circuit includes a differential amplifier circuit with an LPF, an amplifier circuit with a BPF, an inverter, a resistor, and a comparator. The driving circuit applies a driving signal to a piezoelectric element of a piezoelectric pump. The waveform shaping circuit extracts a voltage signal from the driving circuit. On the basis of the voltage signal, the waveform shaping circuit and the computing circuit determine a voltage value corresponding to driving current flowing through the piezoelectric element. The computing circuit outputs a control signal to the boosting circuit on the basis of the voltage value. The boosting circuit sets the value of a DC supply voltage on the basis of the control signal, and outputs the DC supply voltage.

The invention relates to a pump unit that can be driven by an electric motor, in particular for providing vacuum for a pneumatic brake booster, including a pump housing that can be closed by a working-chamber cover and at least one elastic displacement element, wherein a working chamber is bounded between the displacement element and the working-chamber cover and wherein inlet valves and outlet valves and inlet channels and outlet channels associated with the valves are associated with the working chamber. According to the invention, in order to reduce noise emissions, devices for reducing a contact surface between the working-chamber cover and the pump housing are provided.