Patent Application
20080044648
In the accompanying drawing which forms a part of the specification and is to be read in conjunction therewith:
With reference to
In accordance with the present invention, a heat resistant coating 16 is applied to the beam 10 or other structural member. The coating 16 is specially formulated to exhibit heat resistant characteristics and is applied to the beam 10 in any suitable manner to surround all parts of the beam and envelope the beam within the coating.
Preferably, before the coating 16 is applied, reinforcement such as a steel mesh 18 is applied to the beam 10. The mesh 18 is preferably an open work mesh such as a mesh of open gauge wire having a plurality of reinforcement strands 20. The mesh 18 is preferably wrapped around or otherwise applied to the entirety of the beam 10, including the inside and outside surfaces and the edges of the flanges 12 and the opposing surfaces of the web 14. The mesh 18 provides reinforcement that minimizes cracking of the coating 16 if the beam 10 should thermally expand when subjected to high temperatures.
As previously indicated, the coating 16 may be applied in any suitable manner.
Preferably, the coating 16 is applied in a semi-liquid form by spraying it onto the meshwork reinforcing strands 20 and the beam 10 by suitable spraying equipment (not shown). The coating is preferably applied to the entirety of the beam surface, including the outside and inside surfaces of the flanges 12 and their edges, and the opposing surfaces of the web 14.
The coating 16 formulated according to the present invention includes cement, gypsum, perlite and a liquid catalyst that includes styrene acrylic. Those constituents may be mixed with water and sprayed or otherwise applied to the beam 10 and the mesh 18.
The cement is preferably Portland cement due to its ready availability. The gypsum may be of the type commercially available and known as hydrostone gypsum. The cement is preferably present in the coating in an amount between about 26% and about 32% by weight. The gypsum is preferably present in the coating in the amount of between about 22% and about 28%.
The perlite included in the formulation may be of two types. One type may be expanded perlite in the form of fine beads. The perlite beads may be present in the coating in an amount between about 5% and about 11% by weight. Expanded perlite beads in the form of No. 6 classified beads may also be included. The No. 6 beads may be present in an amount between about 0.5% and about 3% by weight. Together, the fine beads and the No. 6 beads are thus present in the coating in an amount between about 5.5% and about 14% by weight. The perlite beads are preferably distributed uniformly throughout the coating.
The catalyst may be a catalyst that includes styrene acrylic. Suitable catalysts are commercially available from GeoBond International under the trade designations GeoBond Catalyst H6 or GeoBond Catalyst C. The catalyst may be in a liquid form and is present in the coating in an amount between about 5.7% and about 12% by weight.
The coating may include water present in an amount between about 26% and about 32%. The dry constituents may be blended and mixed thoroughly with the catalyst and water to provide a homogeneous substance that can be sprayed or otherwise applied to the beam 10 and the mesh 18.
The thickness of the coating 16 can vary. Preferably, the coating is between about ½ inch thick and about 2 inches thick as a practical matter. The coating provides significant protection for the beam 10 against exposure to high temperatures that can cause the beam to fail structurally.
In recent testing, a steel I-beam was coated with the coating 16 to a thickness of about 1 ½ inches. The coated beam was put in a 2000° F. furnace, and the temperature of the beam was monitored. Only after the elapse of four hours and 48 minutes in the 2000° F. furnace did the temperature of the beam 10 reach 1000° F. which is considered to be the temperature at which a steel beam fails structurally. The coating 16 thus provided protection against structural failure for nearly five hours. This compares with the best previously known heat insulating material which testing has established as being able to protect the beam under the same conditions for only slightly more than three hours. It is thus evident that the present invention provides a heat resistant structural member that can withstand high temperatures for a much longer period of time before failing than has been achieved in the past. Additionally, the method of the present invention involves providing high temperature protection to a structural member by first applying the reinforcement (the strands 20 of the mesh 18 or other reinforcement) to the beam 10 and then applying the coating 16 to the reinforcing strands 20 and the beam 10 in a manner to assure high temperature protection of the beam.
From the foregoing it will be seen that this invention is one well adapted to attain all ends and objects hereinabove set forth together with the other advantages which are obvious and which are inherent to the structure.
It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.
Since many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative, and not in a limiting sense.
