The filter is used to filter out impurities and oil in the fuel gas to ensure the normal operation of the burner valve group. According to the quality of gas, the filter should be cleaned regularly. If wet gas is used, the air inlet valve can be closed periodically, the valve under the filter can be unscrewed, and the settled liquid can be discharged into a special container for dumping. Then, the upper cover can be removed, and the fastening screws of the filter screen can be loosened to remove the filter screen and the attached dirt. If clean dry gas is used, the cleaning cycle can be extended.