Multiple-piece vacuum-insulated heating tank of water dispenser

A multiple-piece vacuum-insulated heating tank of a water dispenser, comprising a threaded cover, a thermal insulation cover, and a heating tank body, wherein the threaded cover is mounted on an upper opening of the heating tank body, the upper opening of the heating tank body is formed with an external thread, the thermal insulation cover is fitted in the upper opening of the heating tank body, the heating tank body is a double-layer cup-shaped structure, the heating tank body has a bottom portion mounted with a drain pipe, and the heating tank body is provided with a circular projection adjacent to an opening;

• wherein the threaded cover is composed of a plastic cover and a protective cover, the plastic cover is hat-shaped, a surface of the plastic cover and a surface of the protective cover are formed with identical said openings respectively, the plastic cover has a lower portion provided with an internal thread, and the protective cover is mounted on and around the plastic cover;
• wherein the thermal insulation cover is composed of an upper cover and a lower cover;
• the lower cover is a cup-shaped structure;
• the lower cover has a bottom side mounted with a heating tube, a water inlet pipe, a water outlet pipe, a thermowell, a temperature-sensing heat pipe, a heat collector block, and two snap-action thermostats;
• the temperature-sensing heat pipe has one end inserted into the thermowell and an opposite end inserted into the heat collector block;
• the two snap-action thermostats are mounted on a top side and a lateral side of the heat collector block respectively;
• the upper cover is a flat plate;
• the upper cover has an upper side provided with a wiring hole and a foam material injection hole;
• a space between the upper cover and the lower cover is filled with a thermal insulation layer;
• and the lower cover has a sidewall formed with a step adjacent to the bottom side.