Abstract: The invention discloses a pulsating chlorination machine for purification of city water. The machine includes a body, two ends of which are respectively a water inlet and outlet end between which a converging pipe, a throat pipe and a diverging pipe are connected in turn; and a liquefied chlorine input port located below a middle part of the throat pipe and connecting with the throat pipe via a cone-shaped valve seat. A normally closed cone-shaped valve rod is mounted over the cone-shaped valve seat and inserted into the throat pipe through a vertical circular hole on a top of the body, and moves up and down under the control of a pulsating electromagnetic executive mechanism to open/close the liquefied chlorine input port. Through the liquefied chlorine input port the liquefied chlorine flows into the throat pipe and out from the diverging pipe and then into a clear-water reservoir.

Abstract: A direct chlorination system and device characterized by feeding of liquefied chlorine into water without vaporization in a process that liquefied chlorine from a source liquefied chlorine cylinder is led to a liquefied chlorine settlement cylinder for removal of solid impurities, a metering pump for a pressurization and flow rate control at the metering pump and a liquefied chlorine feeder for mixing with and dissolving in pressurized water to become a high concentration chlorine solution which is then led to a water injector for feeding into a rapid water filter, a mixing basin and a clearing water reservoir for reaction and disinfection before city water is sent to a city water distribution network, and possessing the following merits: upgrading potable water quality, minimizing initial investment, lowering operating cost, and providing a simply but reliable, easy-to-control device that can facilitate water works automation.