Pyrex glass in Chemical Industry, insulators mentioned

[Trade Journal]

Publication: The Glassworker

Pittsburgh, PA, United States
vol. 42, no. 29, p. 13,38,40, col. 1-2,1-2,1-2


INCREASING USE OF GLASS IN CHEMICAL INDUSTRY

Papers Read at Meeting of American Chemcial Society Give Interesting Comment

on Development of Low-Expansion Glass For Use in Various

Chemical Processes.

 

At the spring meeting of the American Chemical Society held in New Haven during the week of April 2, J. F. Greene, of the Kimble Glass Co., of Vineland, N. J., discussed "Glass in the Chemical Industry," and A. E. Marshall, consulting engineer of Baltimore, talked on "Industrial Pyrex." During the meeting, the new chemical laboratory at Yale University, the gift of John W. Sterling, was dedicated.

The following summaries of the papers by Messers Greene and Marshall are from Chemical and Metallurgical Engineering:

GLASS IN CHEMICAL INDUSTRY

"Glass as a material for industrial construction has been known and used for some time. Recently, however, it has seen new application in the use of low-expansion glass for the fabrication of pieces much larger and heavier than any previously attempted. The properties of glass which make it a desirable element in industrial chemical engineering practice are: (1) Its transparency, (2) its possible perfection of finish making a 'glassy finish' a byword for supreme smoothness, (3) resistance to chemical attack, (4) the facility with which it can be blown, drawn, pressed or cast. All these properties are not inherent to the highest degree in all glasses, and usually a glass which rates high in one desirable quality will be less suitable in another respect.

"The disadvantages of glass are likewise more apparent in some types than in others. They are: (1) brittleness and (2) low tensile strength in the piece, due to the enormous influence of scratches and cracks. Two other properties that come in question are resistance to heat shock and easy of annealing. Glasses vary widely in the possession of these qualifications.

"Having in mind the necessary properties of the material which is to compose any industrial piece, the chemical engineer will arrive at a reasonable decision by considering how well any commercial glass meets his specification and how its total cost (first cost and maintenance) will compare with that of any other material from which the piece might be fabricated. It will sometimes be found that a very expensive material will be cheapest in the end due to low maintenance costs and fewer interruptions to production. In other words the cheapest possible material will be the only one really economical.

In application where transparency is the determining factor, glass is almost without a rival. Such applications are sight feed glasses, high-pressure gage glasses, glass plates for peep holes, etc. Sigh feed glasses, gage glasses, etc., are usually connected to a metal fitting. In selecting a glass for this service, accuracy of sizing should be considered, since a good fit is essential. The glass should be selected to meet the temperature, pressure and heat shock requirements of the particular use. The more trying these are the more expensive glass must be used.

"For resistance to chemical attack, glass is excelled in some instances by tin and platinum. It is superior to them in its resistance to phosphides, sulphides and the halogens. Earthenware has the disadvantage of porosity, and chemical stoneware improves in resistance as it approaches a glass in composition. No glass, offers complete resistance to strong alkalis. However, much glass is used as small parts of electrolytic caustic plant, because the attack that takes place does not harmfully contaminate the caustic and the pieces can easily be replaced. Thus are used brine wells, a