CONSOLIDATED, ETC., CO. V. CEOSBY, ETC., 00. 773 �chamber outside the ground joint of a valve, and so regulated by the crack, or opening, between its lip and the main body of the valve, that it will confine or "huddle," as the experts say, the steam, -when it begins to escape from the chamber, and will presently afterwards open more widely and let the steam escape, and not interfere with the rapid fall of the valve before it bas lost too much steam. It holds it up just long enough, His single claim is "a safety-valve with the circnlar, or annular flange or lip, c c, constructed in the man- ner or substantially in the manner shown, so as to opei'ate as and for the purpose herein described. " �The Crosby patents, owned and used by the defendant, describe two forms of valve operating substantially alike,and ■which I can describe sufficiently without nicely discriminat- ing between them. The valve is so made that, when it rises, an additional part of its under surface is exposed to the action of the steam in the chamber. This additional part is either masked or neutralized until the valve .begins to rise. This furnishes an additional lift, proportioned to the addi- tional area now exposed. The pressure of the steam in the chamber is further regulated and adjusted, thus : When the valve rises, it opens a way for the steam into a smaller cham- ber inside the principal one. This lesser chamber has several outlets to the air below, the sum of whose area is about equal to that of the lesser chamber itself. If these holes are all open, there is simply a free escape of steam below as well as above, though not of the same size; and the operation is like that of an ordinary old-fashioned valve, except that it has a vent below as well as above. But, in practice, the holes are rarely left wide open ; and the most approved means of clos- ing them to the desired extent are found in a brass ring or sleeve, fitted by a screw-thread to a thread on the outside of the casing. In the second patent, this sleeve is described, instead of the stop-cocks and bushings mentioned in the first patent: "This sleeve is of cup shape, or has an upturned annular flange, which directs upward the escaping steam." When these holes are thus diminished, there is a "huddling" of steam, as the plaintiff calls it, or a differential pressui'e, as the specifications describe it; that is, the amount of ��� �
