What is Emisshield®?
The core Protective Ceramic Coating (PCC) Emisshield® technology was originally developed by NASA in 1994. This technology was to be used as the heat shield for the X-33 and X-34 Space Plane programs. Often, NASA licenses technologies to the private sector and thus this formula was obtained by Emisshield® in 2001. After research and development with the Virginia Tech Adhesion and Sealant Science Department to modify and improve performance capabilities, Emisshield® was introduced for commercial industrial applications.
How does Emisshield® work?
Emisshield products offer many benefits because they are high-emissivity nanoparticle ceramic coatings; improving the transfer of radiant heat.
Emissivity is the ratio of total radiative output from a body per unit time per unit area at a specific temperature and wavelength to that of a black body under the same environmental conditions.
All substrates have an emissivity value and this value is reported from 0.0 (lowest) to 1.0 (highest). If a substrate has a surface emissivity of 1.0, it is considered a black body. No known substrate is able to absorb all energy and re-radiate that same energy perfectly as a black body would; but grey bodies do exist. These grey bodies can absorb and re-radiate a portion of energy of the theoretical black body. Emisshield products are grey bodies as they absorb and re-radiate a comparable proportion of energy a black body would under the same conditions.
Many substrates report high emissivity values at ambient temperatures but as temperatures increase these values rapidly decrease. At these ambient temperatures some substrates are able to absorb and re-radiate almost as much energy as a black body would, incorrectly classifying them as grey bodies.
However, physical characteristics of these substrates limit their temperature capabilities. PCC was developed to maintain its high emissivity value throughout the space ship re-entry process which can range in temperature from -250°F to almost 3000°F. Emisshield® products possess the same capabilities and will absorb and re-radiate energy at the same ratio across a wide temperature range because of the complex ceramic nanoparticle matrix that comprises Emisshield®. Thus, emissivity is a function of temperature in that as the temperatures rise, the re-radiation potential increases. And, as temperatures fluctuate Emisshield® products are able to maintain their emissivity values of 0.85 -0.98 and offer much more re-radiation predictability.
Why is a High Emissivity Technology Important for Industrial Processes?
When Emisshield® is applied to refractory linings, the coating absorbs up to three times more radiant and convective heat from the burner flames and hot gases than uncoated refractory. Heat absorbed by the coating is immediately re-radiated to the cooler load. As more heat is made available the flue gas temperature will decrease because less of the available heat is absorbed and stored in the lining and the refractory materials stay cooler and are less subject to thermal shock and thermally-induced stresses. Longer refractory life will result while lower substrate temperatures reduce devitrification and associated shrinkage of refractory ceramic-fiber modules, boards, and blankets. Consequently, the maintenance costs of fiber-linings coated with Emisshield® are significantly lower. This same idea relates to all Emisshield® coated metals.
Since Emisshield® reduces the amount of heat absorbed by the refractory, coated IFB linings and dense refractory linings behave more like low thermal mass linings. More heat is available to heat treat parts rather than heating the furnace lining or escaping out the flues. In addition to the obvious energy saving, the reduction of absorbed energy by the lining allows faster heat-ups and quicker temperature recovery when cold loads are inserted. This will shorten cycle time, increase capacity and improve productivity.
When Emisshield® is applied to linings; they become more efficient heat radiators. This improves the uniformity of radiant heating and the quality of the treated parts.
One of the most important benefits of using Emisshield® is fuel savings. Emisshield® users routinely report fuel savings from 6% to over 20%, depending on how their unit processes are designed and operated. The harder a process is pushed, the greater the fuel savings and the faster the payback. The Emisshield® team will work with you to insure that you achieve the greatest benefit from your investment in this unique product.
Please click the video below to see Emissield’s re-radiating and multi-functional capabilities.