Coupler for discharging chemicals

A coupler for discharging a chemical outside a container, through an internal coupler unit coupled to a chemical outlet port of the container and then through an external coupler unit coupled to the internal coupler unit, wherein the external coupler unit comprises:

• a main housing comprising a cylindrical body having a hollow space therein, with upper and lower coupling seats respectively formed in upper and lower ends of the main housing and having respective internal threads therein, and a side hole formed through a sidewall of the main housing and communicating with the hollow space of the main housing;
• a hollow rod member inserted into the hollow space of the main housing and having a structure such that a lower end of the hollow rod member protrudes from a lower end of the main housing and an upper end of the hollow rod member engages with the upper coupling seat of the main housing, with an internal thread formed on a circumferential inner surface of the upper end of the hollow rod member;
• a hollow cylindrical member having on a circumferential outer surface of an upper end thereof an external thread to be tightened into the lower coupling seat of the main housing, with a stopper protruding outwards from a lower end of the hollow cylindrical member;
• a subsidiary housing fitted over the hollow cylindrical member and stopped by the stopper of the hollow cylindrical member, with an external thread formed on a circumferential outer surface of a lower end of the subsidiary housing to couple the subsidiary housing to the internal coupler unit;
• a fluid opening control unit provided in the lower end of the hollow rod member and having a spring and a valve, which are coupled to each other and are respectively supported at upper and lower predetermined positions in the lower end of the hollow rod member;
• a pumping means connector coupled to the upper end of the hollow rod member to connect the external coupler unit to a pumping means for pumping the chemical outside the container;
• a gas injection means connector tightened into the side hole of the main housing to connect the external coupler unit to a gas injection means for injecting gas into the container;
• and
• a plurality of sealing caps to close respective openings of the pumping means connector and the gas injection means connector when the pumping means connector and the gas injection means connector are not in use.