NOVELTY - Methane generator part of constant temperature methane generator comprises inner and outer walls prepared by a steel plate or a cold-rolled plate, a chamber formed by inner and outer walls to preserve the temperature, which is injected with polyurethane foaming plastic, and an organic glass-steel anti-corrosive material layer coated on the steel plate or the cold-rolled plate on the inner wall of the generator (the anti-corrosive coating can be replaced by high melting-point asphalt) to prevent the corrosion of the steel plate or the cold-rolled plate.    USE - Used as a methane generator part of constant temperature methane generator.    ADVANTAGE - The device: is provided with two temperature controllers for detecting the temperatures in the solar concentrator and the methane generator; and controls the working status of the hot water circulating pump to maintain the temperature of the liquid in the methane generator at constant temperature, and thus it ensures the normal gas production in four seasons.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a solar concentrator heating part of the constant temperature methane generator, comprising a radiating water tank connected with the solar concentrator by a thermal insulating tube. A hot water circulating pump is connected on the thermal insulating tube. The hot water in the solar concentrator is pumped to the hot water tank for heating the hot water in the methane generator, where the control lines of the solar temperature controller and the liquid temperature controller are connected on the firing line of the hot water circulating pump to control the operation of the hot water circulating pump. The temperature sensor of the solar temperature controller is arranged in the thermal insulating water tank of the solar concentrator, and the lower limit temperature of the hot water circulating pump is set. The temperature sensor of the liquid temperature controller is mounted in the liquid of the methane generator and the upper limit temperature of the hot water circulating pump is set, when the temperature of the liquid and the water temperature in the solar temperature concentrator is fit for the requirements, the hot water circulating pump starts to operate for heating the methane liquid.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the methane generator part of constant temperature methane generator.