Casing, usually used in the basement of the building, is used to protect the pipeline or to facilitate the installation of the iron ring. When the casing is used in the pipeline with hot steam, it requires the casing to have good heat insulation and heat dissipation effect, so as to ensure the service life of the casing applied in the above pipelines; However, the casing in the existing technology is difficult to meet the requirements of good heat insulation effect, simple structure and low manufacturing cost.

      In view of the above technical problems, the object of the invention is to propose a heat insulation fireproof sleeve with simple structure and effective heat insulation effect.

      The upper and lower sides of the heat insulation groove of the casing body are respectively connected with an air vent whose diameter is smaller than the heat insulation particles, and the air vent extends up to the outer surface of the casing body. Four air holes are evenly arranged on the upper and lower sides of the heat insulation groove of the casing body. Due to the application of the above technical scheme, the invention has the following advantages compared with the prior art: 

      The heat insulation and fireproof sleeve has simple structure and low manufacturing cost. The sleeve is provided with a ring groove on the inner wall of the circular through hole, which can reduce the contact area between the inner wall of the sleeve and the pipe, and thus reduce the heat transfer between the sleeve and the pipe; And a heat insulation groove with heat insulation particles is arranged on the pipe sleeve, which can absorb the heat transmitted from the pipe in time, so as to effectively ensure the heat insulation effect of the sleeve; At the same time, air holes are arranged at the upper and lower sides of the heat insulation groove, so that the air in the heat insulation groove can exchange heat with the outside air, which further improves the heat insulation effect of the sleeve.