What are advantages/disadvantages of using direct vs. indirect steam?
Denig: The type of heat source plays a role in how fast you can sterilize pallets and the amount of checking and splitting present after treatment. There are four typical heat sources for a heat chamber direct fired heating sources, indirect fired heating sources, indirect steam and direct steam. Direct fired heating sources are probably the least expensive in terms of capital cost. The best analogy of this is heating your house by using gas-fired logs. You have to bring in outside air to burn with the fuel. Bringing in outside air uses more heat because you have to continuously heat the air. Because you are taking relatively cool air and heating it, you are increasing the water holding capacity of the air or in other terms, decreasing the relative humidity. The heat in the air that is transferred to the pallets will initially be used to dry the surface of the pallets versus heating the pallets. Because the pallets are drying, this system will pose a greater problem of checking and spl
