Parsons v. United States

Court of Claims

Parsons v. United States

75 Ct. Cl. 751, 1932 U.S. Ct. Cl. LEXIS 281, 1932 WL 2117

CourtUnited States Court of Claims

DecidedNovember 14, 1932

DocketNo. D-503

StatusPublished

This text of 75 Ct. Cl. 751 (Parsons v. United States) is published on Counsel Stack Legal Research, covering United States Court of Claims primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook

Parsons v. United States, 75 Ct. Cl. 751, 1932 U.S. Ct. Cl. LEXIS 281, 1932 WL 2117 (cc 1932).

Pincite

Opinion

LittletoN, Judge,

delivered the opinion of the court:

The patents in suit all relate to steam turbines, in which the steam, admitted at relatively high pressure into one end of the turbine casing and exhausting at lower pressure at the other end of the turbine, yields energy due to its expansion which directly rotates the shaft of the turbine through the instrumentality of turbine blades or “ buckets ” fixedly attached to the turbine shaft.

Steam turbines are of two principal classes; namely, reaction and impulse turbines. These two classes operate upon different principles. In the former the rotation of the shaft is primarily caused by the reaction or “ kick-back ” of the steam against the moving blades carried by the shaft due to a drop in pressure and consequent expansion as it issues from the channels between these blades.

Parsons was the leading exponent and developer of reaction turbines. All the patents in suit show reaction turbines.

The principle of operation of an impulse turbine is that the steam expands in its passage through stationary nozzles, thus acquiring high velocity, and the momentum of the jets of steam issuing from these nozzles at high velocity and impinging against blades attached to the shaft causes the shaft, to which they are attached, to rotate. All of the Government turbines involved in this case, with the exception of certain turbines made by the Westinghouse Electric & Manufacturing Company, are impulse turbines.

[790]*790Turbines may be simple or compound. In a simple turbine there is only one series of rotating blades if the turbine be of the reaction type, and only one series of nozzles and one series of rotating blades if it be of the impulse type. In a simple turbine all the energy of the steam is extracted in one stage, by one drop in steam pressure. The energy of the steam can not be economically extracted in a single stage and, therefore, in modern practice, turbines are usually pressure-compounded, being constructed with a series of pressure stages, each stage involving, in the case of a reaction turbine, a ring of moving blades attached to the shaft and a ring of fixed blades carried by the casing, the function of which fixed blades is to redirect the steam issuing from the ring of moving blades so that it will enter the next ring of moving blades at the proper angle; and, in the case of an impulse turbine each stage involving a series of fixed nozzles and a ring of rotating blades. At each stage there is a drop in steam pressure amounting only to a portion of the total pressure drop from inlet to outlet of the turbine, and the energy of the steam is thus extracted in a series of successive stages instead of in one as in the simple turbine. An impulse turbine may be velocity-compounded as well as pressure-compounded. There may be in a single pressure stage of an impulse turbine a plurality of rings of moving blades, instead of a single ring of moving blades, each ring extracting a portion only of the velocity of the steam passing through the stage.

Turbines may also differ in detail as to the direction in which the steam passes through the blades. In some cases the steam passes through the blades to which it gives up its energy in a direction generally parallel to the shaft of the turbines, the blades being appropriately mounted. Such turbines are called parallel or axial flow turbines. In other cases the general direction of the steam as it passes through the moving blades is radial to the turbine shaft, the blades here being differently mounted. Such turbines are described as radial-flow turbines. Parallel-flow turbines are more commonly used than radial-flow turbines, but both are practical forms.

[791]*791The first patent in suit, No. 708780, was issued September 9,1902, on an application filed February 13, 1900. Claims 1 and 2 are charged to be infringed.

This patent shows combined ahead and reversing turbines, both of the reaction type, mounted on the same shaft and in a common casing and having a common exhaust passage to the condenser. Both turbines are shown as compound turbines, having a large number of rings of fixed blades mounted on the casing and a large number of rings of moving blades interspaced between the rings of fixed blades and mounted on the ahead drum and the reversing drum, respectively.

The patent shows Figs. 1, 5, and 6, respectively, three different combinations of ahead and astern turbines, as follows:

[792]

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