Abstract: A method for collecting particles or gaseous chemicals is provided. The method includes providing liquid to a tube of a droplet generator, heating, with a heater of the droplet generator, the tube to provide vapor to a gas flow channel inside the tube, passing a gas flow containing the particles or gaseous chemicals through the gas flow channel inside the tube to obtain droplets including the particles or gaseous chemicals, and passing the droplets including the particles or gaseous chemicals to a wall of a collecting device such that the droplets including the particles or gaseous chemicals hit the wall. The temperature inside the gas flow channel is higher than a temperature inside the collecting device.

Abstract: A droplet generator includes a chamber including an enclosed space filled with gas having vapor, a tube extending through the chamber, a gas flow channel inside the tube, and a heater in the chamber. The tube includes a sidewall having an outer surface exposed to the enclosed space of the chamber, and an inner surface. The tube contains liquid. The heater is operable to change a phase of the liquid contained in the tube to vapor such that the vapor is provided into the enclosed space. A pressure in the enclosed space is higher than a pressure in the gas flow channel such that the vapor in the enclosed space flows to the gas flow channel by passing through the tube.

Abstract: A method for collecting particles or gaseous chemicals is provided. The method includes providing liquid to a tube of a droplet generator, heating, with a heater of the droplet generator, the tube to provide vapor to a gas flow channel inside the tube, passing a gas flow containing the particles or gaseous chemicals through the gas flow channel inside the tube to obtain droplets including the particles or gaseous chemicals, and passing the droplets including the particles or gaseous chemicals to a wall of a collecting device such that the droplets including the particles or gaseous chemicals hit the wall. The temperature inside the gas flow channel is higher than a temperature inside the collecting device.

Abstract: A droplet generator includes a chamber including an enclosed space filled with gas having vapor, a tube extending through the chamber, a gas flow channel inside the tube, and a heater in the chamber. The tube includes a sidewall having an outer surface exposed to the enclosed space of the chamber, and an inner surface. The tube contains liquid. The heater is operable to change a phase of the liquid contained in the tube to vapor such that the vapor is provided into the enclosed space. A pressure in the enclosed space is higher than a pressure in the gas flow channel such that the vapor in the enclosed space flows to the gas flow channel by passing through the tube.