Combined type centeralized draft tube special for solar water heater

The utility model discloses a combined type centeralized draft tube special for solar water heater, which is composed of an external assembly casing tube portion and a built-in water pipe portion. Wherein, the built-in water pipe portion is arranged in the external assembly casing tube portion, and the external assembly casing tube portion comprises an indoor straight casing tube, an insulation bottom connected bend casing tube, an insulation draft tube section, and an insulation extension casing tube. The built-in water pipe portion comprises built-in upper water tubes and built-in lower water tubes in each group. The utility model has the advantages that the draft tube is used by inhabitants to install a solar water heater. A plurality of groups of upper water tubes, a plurality of groups of lower water tubes and overflow tubes are preinstalled in the interior of the assembly casing tube, and are used for the family splitting usage of the inhabitants. So the installation and detachment are convenient and easy. The insulation draft tube section is arranged outdoors, which makes the upper water tubes, lower water tubes and overflow tubes of the solar water heater connected by the means of family splitting, and realizes uniform insulation. At the same time, the utility model also has the advantages of simple structure, low cost, convenient assembly, etc. In addition, the installation of the solar water heater is convenient, and the normal use of the solar water heater can be ensured after the installation.