Abstract: A liquid delivery method and apparatus which can suppress generation of turbulent flows and air bubbles, In the liquid delivery method and apparatus for delivering a liquid by reciprocally moving a plunger in a cylinder while a selector valve is shifted in a valve chamber to change over communication of the cylinder and the valve chamber with a channel leading to a liquid tank and communication of the cylinder and the valve chamber with a channel leading to a delivery port from one to the other, the cylinder and the valve chamber are communicated with the channel leading to the liquid tank and an opening/closing valve disposed between that channel and the liquid tank is opened when the plunger is retracted, and the cylinder and the valve chamber are communicated with the channel leading to the delivery port and the opening/closing valve is closed when the plunger is advanced.

Abstract: To deliver a liquid at high speed and with high accuracy. A device for delivering a fixed quantity of liquid, comprising a pump section for metering the delivered liquid to provide a desired amount consisting of a plunger chamber formed in a cylinder block, and a plunger reciprocating in the plunger chamber, a valve section for switching between liquid flow channels for suction and delivery, a reservoir section for reserving liquid adapted to communicate with the pump section depending upon the position of the valve section, and a delivery section having a delivery port for delivering liquid, the device being characterized in that the pump section and the valve section are disposed connected to each other and that the maximum advance position of the plunger is defined by a plane where the front end surface of the plunger contacts the valve section and pump section. The valve section is removably disposed in the pump section.

Abstract: The invention intends to prevent the occurrence of a phenomenon that air is sucked through an ejection port formed at a nozzle end when a plunger rod is retracted to move away from a valve seat. In a method or apparatus for ejecting liquid droplets in which a liquid under regulated pressure, the liquid being stored in a container as required, is ejected while it is caused to fly in the form of liquid droplets from a valve ejection port, bubbles are prevented from being mixed into the liquid through the ejection port by controlling a supply amount of the liquid in a manner being able to follow a pressure difference between the ejection port and a flow passage in a valve body. The liquid is continuously ejected at a high-speed tact. The ejection port is opened with a plunger rod retracted by air pressure, and the liquid droplet is ejected through the ejection port with the plunger rod advanced by a resilient force of a spring.