US1743303A - Alloys - Google Patents

Description

Patented Jan. 14, 1930 FRANK W. ANIIREWS, OF DAYTON,

OHIO, ASSIGNOR, BY MES NE ASSIGNMENTS, TO

FRIq-IDAIRE CORPORATION, A CORPORATION OF DELAWARE ALLOYS No Drawing.

This invention relates to compositions of matter, particularly to alloys designed to be lu'ied for gaskets, packing material and the One of the objects of the invention. is to provide a metal which issufficiently plastic to flow under moderate pressures so as to conform which it is in contact. It is'also an object of ,the invention to provide a metal having the above characteristics which has a coeflicient of thermal expansion close to that of the parts with which it is to be used.

Further objects and advantages of the present invention willbe apparent from the following description.

In constructing machinery having rotating parts whose bearings must be sealed against the passage of gas, for example conipressors used in refrigerating apparatus, con-' siderable dilficultyhas been encountered in packing the stuffing box which ordinarily surrounds the rotating shaft. 7 My invention contemplates a metallic packing which, due to its plasticity, can be made to conform accurately to the shape of parts of machinery so as to form a. gas-tight seal and which, due to its coeflicient of expansion, maintains such sealing contact thruout the variations in temperature encountered in the operation of such machinery.

In the example mentioned, the machine parts are ordinarily made of cast iron and steel, metals having coeflicients of expansion sufliciently near each other to be considered thesame thruout the temperature range under consideration. It is therefore important that the coefficient of expansion of the packing be substantially or approximately the same as that of iron or steel. For if the packing metal expands at a widely differing rate, it will, as the temperature rises, either recede from the parts to cause leaks, or expand into such tight contact as to produce excessive friction, which may stop the machinery, if of small power, heating.

I have discovered that alloys containing from 90% to 95% lead and the rest either tin and bismuth, or tin, bismuth and antior injure the parts through over- Application filed April 28,

a u o u g I to irregularities 1n surfaces with '1927. Serial No. 187,358.

mony, are well adapted to the purposes above described. Such alloys are sufliciently plastic to meet the requirements of gaskets and packing glands and their coeflicients of expansion are sufliciently near the coeflicients of cast iron and the various steels with which they will be used. The coeflicient of expansion may be varied to suit requirements by slightly varying the proportions of the constituent metals.

For example I find that an alloy of 95 parts so lead, 3 parts bismuth, and 2 parts tin has a coeflicient of expansion corresponding to that of steel such as ordinarily used for compressor shafts and that these proportions may be varied slightly without materially effecting the result. The lead, being greatly in excess of the other components, can be varied to agreater extent without materially changing the result. As particular examples of the component elements of which I may make my alloy, and their proportions, I mention the following:

N Example 1 Lead 90-96 parts 7 Tin 1-3 parts Bismuth 2-4 parts Example 2 Lead 90-96 parts so 'Iin 4-6 parts Bismuth 1-3 parts Antimony 1 3 parts I claim as my invention: A plastic metallic packing composition havmg coeflicient of expanslon approximating that of cast iron and steel and consisting of lead, tin and bism th in the following proportions: K Lead" 90 to 96 parts .Tin 1 to 3 parts Bismuth 2 to 4 parts In testimony whereof I hereto afiix my signature.

FRANK W. ANDREWS.