ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1921.tb17362.x

出版商:Blackwell Publishing Ltd    

年代:1921

数据来源: WILEY

摘要:

ABSTRACTData obtained.—This paper presents measurements of the following factors and properties and their influences upon fish scaling in the case of typical single and three‐coat enamels: time and temp. during melting of the frit; fusibility of the enamel; coeff. of expansion of the enamel, and of a variety of representative irons and steels up to 500°C (accuracy about 0.1%); annealing the enamel coat after firing; chem. comp. of the steels and irons; mechanical treatment (rolling, spinning, drawing, and so forth of the stock; microscopic surface structure of the stock; effect of chem. comp. upon thermal expansion of enamel.Incidentally it was found that the formulas of Mayer and Havas for computing the thermal expansion of enamel from its chem. comp. can not be relied upon:Conclusions.—On the basis of these exhaustive tests, the following conclusions have been drawn as to the causes and the control of fish scaling.(A) Causes.—1. The cause of fish scaling lies in the difference of the coefficients of expansion of the enamel and the stock, that for steel being higher than for enamels so that the latter are under a compressive stress. The factors influencing this phenomenon are as follows: (a) Composition of the enamel as affecting the coefficient of expansion of the enamel; (b) Overfiring—thus volatilizing those substances which tend to keep the coefficient high; (c) Lack of annealing enameled ware, the enamel coating of which is a glass and should logically be treated as such.2. Fish scaling is due secondarily to a number of factors which may affect the strength of the enamel or its adherence to the metal. (a) The physical condition of the surface of the metal as influenced by drawing, spinning, cold rolling or other mechanical treatment; (b) Composition of the glass as affecting its elastic strength; (c) Underfiring, enamel not fused to metals; (d) Cleanliness of the surface as regards removal of drawing compounds, grease, etc.(B) Remedies.—1. (a) Adjusting the composition of the enamel so as to increase its coefficient, e. g., by decreasing the boric acid content; (b) Correct firing of the enamel to avoid unnecessary volatilization of such fluxes as soda and cryolite; 2. (a) Adjusting enamel composition to increase its strength; (b) Correct firing to give proper adherence. 3. Treatment of metal to give best adhesion by (a) cold rolling or other suitable mechanical treatment of the untreated steel; (b) thorough cleaning.(C) Summary.—Broadly stated, then, fish scaling can be absolutely controlled by one or all of the following methods: (1) By the development of an enamel with an expansion fitting the metal; (2) by annealing the enameled ware; (3) by treatment of the metal as cold rolling or some other method of working: (4) by developing an enamel with a wide range of compressional elasticity and applying this enamel to metal treated as i

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1921.tb17363.x

出版商:Blackwell Publishing Ltd    

年代:1921

数据来源: WILEY

摘要:

ABSTRACTIn the manufacture of glassware it is important to distinguish between surface‐markings and cords, both of which are serious defects and detrimental to quality. To do this immerse the piece of glass under test in a liquid of the same refringence and sight through liquid and glass toward a distant light. Under these conditions surface‐markings disappear altogether. Cords, on the other hand, stand out more distinctly than before.The relative refringence of a cord compared with that of the adjacent glass can also be determined at the same time. For ordinary crown glasses monochlorbenzene is suggested as an immersion liquid. To lower its refractive index add benzene; to raise it add carbon bisulfide or monochlornaphthal

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1921.tb17364.x

出版商:Blackwell Publishing Ltd    

年代:1921

数据来源: WILEY

摘要:

ABSTRACTThe effect of calcined zirconia on zirconia cement. Seven refractory cements were made having compositions of zirconia 90 per cent and plastic clay 10 per cent. (1) The shrinkage was found to be excessive in a cement containing raw zirconia and clay. The addition of 50 per cent or more of calcined zirconia practically eliminated this shrinkage and the cracking which accompanies it.(2)Strength Draw trials showed that the cement became strong at 1200°C and that it was very strong when burned at 1700°C. (3)Load tests on piers at 1500°C showed that joints of these cements did not fail in any manner at this temperature. (4) An industrial test of zirconia cement used as a wash for bungs in a malleable iron furnace showed that the life of a bung was increased about 25 per cent by the use of a zirconia wa

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1921.tb17365.x

出版商:Blackwell Publishing Ltd    

年代:1921

数据来源: WILEY

摘要:

ABSTRACTSpecific Installation.—Describes installation of Underwood System to six terra cotta kilns at plant Northwestern Terra Cotta Company.Conclusions from operating data.—(1) Raw producer gas can be successfully applied to periodic muffle kilns. (2) There is little or no direct fuel economy over direct firing. (3) There is no labor economy unless the installation be large enough to justify mechanical coal and ash handling devices. (4) When interest on investment, depreciation and all other pertinent factors are taken into account, it is not likely that any great economy would be affected on periodic kilns over direct fire methods.Advantages.—They are: (a) Somewhat better control of combustion gases and kiln temperatures. (c) Cleaner and more orderly kiln yard. (d) Abatement of smoke nuisance, particularly important in large c

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1921.tb17366.x

出版商:Blackwell Publishing Ltd    

年代:1921

数据来源: WILEY

摘要:

ABSTRACTThese two direct‐fired kilns (bisque and glost) are placed end to end in a specially constructed kiln building 825 feet long. Both kilns are fired with soft coal, hand stoked. Three motors are required, aggregating 8/14 horsepower on each kiln. Hydraulic car pushers are employed. A pressure of 8100 lbs. is required to move the 44 cars thru the bisque kiln. The bisque kiln cars hold 278 dozen ware each and at a 55‐minute car schedule, deliver over 7200 dozen ware per 24 hours at a fuel saving of more than 85% over the former periodic kiln operating at this plant. This bisque capacity is equivalent to that of thirteen 16/12 ft. diameter periodic kilns which would cost more to build than the bisque tunnel k

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1921.tb17367.x

出版商:Blackwell Publishing Ltd    

年代:1921

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1921.tb17368.x

出版商:Blackwell Publishing Ltd    

年代:1921

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1921.tb17369.x

出版商:Blackwell Publishing Ltd    

年代:1921

数据来源: WILEY