The Moss reciprocating grate combustion system is used for burning waste wood materials such as bark, sawdust, wood shavings, plant trimmings, lumberyard waste and sanderdust and also various biomass fuels. This grate design can be used on our hybrid, watertube, A - type, HRT, firebox or field erected watertube boiler systems. Depending on the characteristics of the fuel to be burned, the fuel can be either fed by gravity or pneumatically spread on the grate. Our reciprocating grate combustion system can handle a wide range of waste including low BTU value - high moisture - bulky and irregularly sized fuels. The walking floor movement pushes the fuel down the moving grate and in doing so provides drying in the first stages, proceeding to a gasification process where gases are burned off in our custom designed high - velocity overfire air system (promotes low CO & VOC emissions) and once all the carbon is burned from the waste fuel finally is discharged as a sterile ash. Ash drops off the end of the grate into an ash handling system for continuous automatic ash removal.

The reciprocating grate is an over or gravity feed type stoker complete with hydraulic power pack. In the case of gravity feed, the fuel is fed from the boiler front and the ash discharge will be at the rear of the combustion system. In the case of pneumatic (over) spreading of the fuel, the fuel is burned in suspension as well as on the reciprocating grate surface with ash discharge at the front end of the boiler. Generally, the ash is removed by a wet drag chain conveyor system.

The multi-zone reciprocating grate consists of cast iron bars mounted on shafts for long grate bar life. Alternate shafts are connected together and actuated by a hydraulic driven mechanism to achieve the reciprocating action. There is one fixed shaft by the side of each oscillating shaft. The stroke length can be varied by adjusting the limit positions of the hydraulic direction control valve and the speed of oscillation is based on the firing demand on the system. The grate castings are made of proprietary high temperature grade cast iron with chromium as the main alloying element. The nearest ASTM standard is A 319 -71 - "Grey Iron Castings for elevated temperatures for non-pressure containing parts."