How We Make Steam: Clayton Steam Generator once-through, forced-flow, water tube boilers use a steel helical coil heat exchanger. All fired and unfired steam generators contain a helical coil heat exchanger, a positive displacement feedwater pump and a mechanical steam separator.
The feedwater pump is a heavy duty, pack-less and seal-less positive displacement unit. It is designed and manufactured by Clayton Industries. When the coil tube boiler is operating, the pump supplies continuous feedwater to the helical coil heat exchanger. There, heat is transferred from the combustion products to the feedwater. Feedwater flow counters the flow of the combustion gases. This contributes to the high fuel-to-steam efficiency of the Clayton Steam Generators. The amount of feedwater flow varies relative to the firing rate of the unit, making the steam pressure extremely consistent and the boiler highly efficient which does not decline with firing rate. Extra feedwater is supplied to the coil to assure good heat transfer and internal water circulation throughout its operating range.
A mechanical steam separator is then used to effectively separate the liquid and vapor mixture as it exits the coil and provides consistent steam quality throughout the process, 99.5% or higher quality in most cases.
This offers several design advantages over conventional units because of its inherently-low water volume. Among these benefits are:
- Compact size and low weight
- High fuel-to-steam efficiency
- Rapid startup and excellent load following response
- Low blowdown rates
- High level of operator safety
See Boiler and Steam Deinitions for terms regarding design advantages.