Liquid delivery device and liquid spray device

A liquid delivery device, comprising:

• a cylinder having a liquid retention section configured to retain a liquid;
• a piston in the cylinder, wherein the piston is configured to:
• change a volume of the liquid retention section;
• and
• stop the change in the volume when the volume of the liquid retention section reaches a first predetermined volume;
• a plurality of regulation sections in the cylinder, wherein the plurality of regulation sections is configured to:
• stop movement of the piston at a first position in a case where the liquid is supplied to the liquid retention section;
• and
• stop the movement of the piston at a second position in a case where the liquid retention section becomes to have a second predetermined volume;
• a gas container configured to encapsulate a gas at pressure exceeding atmospheric pressure;
• a regulator which is coupled to the gas container, wherein the regulator is configured to adjust pressure of the gas delivered from the gas container;
• a gas flow channel having a supply flow channel configured to supply the gas delivered from the regulator to the piston, and a release-to-atmosphere flow channel configured to release the gas delivered from the regulator to an atmosphere;
• and
• a three-way valve which is provided to the gas flow channel, wherein
• the three-way valve is configured to switch between a first state in which the gas delivered from the regulator is delivered to the supply flow channel, and a second state in which the gas delivered from the regulator is delivered to the release-to-atmosphere flow channel,
• the supply flow channel includes a first gas flow channel between the regulator and the three-way valve, and a second gas flow channel between the three-way valve and the cylinder in the first state, and
• the release-to-atmosphere flow channel includes the second gas flow channel between the three-way valve and the cylinder, and a third gas flow channel between the three-way valve and the atmosphere in the second state.