Online-jetting scale removing and preventing device for oilfield four-in-one fire tube

The utility model relates to an online-jetting scale removing and preventing device for oilfield four-in-one fire tube used for heating an oil well to produce fluid in the process of oilfield development. The online-jetting scale removing and preventing device comprises the fire tube, a manifold support is fixed on the fire tube, a jetting nozzle manifold parallel to the fire tube is fixed on the manifold support, jetting water incoming tubes are connected on the jetting nozzle manifold, and a plurality of jetting nozzles are arranged along the axis direction of the jetting nozzle manifold. The online-jetting scale removing and preventing device utilizes high-pressure hydraulic jet to flush the top surface of the fire tube, and impurities like scale and silt deposited on the top surface of the fire tube can be removed regularly and timely without stopping production to avoid dirt from continuing depositing and thickening, so that heat efficiency of the fire tube is improved, the service life of the fire tube