He utility model hi double-layer grate vertical positive combustion pressureless boiler siam that a ni. Grate plate tin hian convex arc ang chi working surface structure an nei a, fixed shaft hmangin an thawk a; Tui pipe grate-a kal thei rectangular movable grates set a nei a, chubakah chuan tui pipe grate-a movable grates dahna tur coal feeding port leh movable grates lakchhuahna tur slag cleaning port a awm bawk.
