Patent GB-190628951-A (GB)
Title: Improvements in and relating to the Conversion of Kinetic into Potential Energy in Fluids.
Inventor: FERRANTI SEBASTIAN ZIANI DE
Filed: 1906-12-19
Granted: 1908-03-19
Abstract: 28,951. Ferranti, S. Z. de. Dec. 19. Centrifugal pumps; fans.- Relates to the conversion of the kinetic energy of a fluid into potential energy by means of nozzles, and consists in means whereby the highvelocity fluid is projected into or passes into the increasing-area or pressure-raising portion in such a manner that the individual stream lines are caused to diverge before compression takes place, and consequently the fluid completely fills the increasing-area portion without any change of direction being selfimparted during compression. This method of projecting a fluid is stated to be applicable in connexion with fluid-compressors, injectors, ejectors, pumps, &c., and fluid-compressors are described in which a rotary impeller is employed to project the fluid into a pressure-increasing area or nozzle. Three general types of nozzles are described. In the first, the fluid is directed into a pressureincreasing area in the form of a conical passage e, Fig. 1, with parallel walls, the divergence of the individual stream lines into a direction parallel to the walls, being effected by a conical member c, which is connected by webs to a ring d and is inserted with its apex at the throat b. In the second type, fluid is diverted by guides f, Fig. 2, from an axial direction, and thereby directed into an increasing-area passage formed between parallel disks h, g leading to an annular chamber i, the stream lines diverging radially. The guides may be dispensed with, the impact of two streams being sufficient to cause the change of direction ; and apparatus having one entry pipe only, with a modified guide, may be used. In the third type, the fluid flows radially inwards between parallel walls and is then guided through a curved annular passage of approximately constant cross-sectional area so that it flows radially outwards, the apparatus forming a convergent-divergent nozzle with radial stream lines in both the velocity and pressure-increasing portions. These nozzles may be applied in apparatus dealing with inelastic fluids. Figs. 4 and 5 show a fluid-compressor in which an impeller n with inlet guide-blades s is provided with blades p adapted to project the fluid in a non - radial direction into a pressure - increasing area g having parallel walls. The area g is provided with thin division-pieces or guides r, which are arranged so that the stream lines of the fluid cross zones of constant pressure substantially at right - angles, whereby the disturbance due to oblique projection into an increasing pressure zone is avoided. The impeller may be velocity-compounded, that is, provided with several alternate rotary and stationary rings of blades. or with alternate rings which rotate in opposite directions. The blades of the impeller are preferably arranged so that the passage between them is wider at the inlet than the outlet so as to prevent the formation of dead spaces therein, the sides of the blades being inclined if a path of constant area between the blades is desired. Figs. 6 and 7 show a form of compressor in which the fluid is projected radially into the pressure-increasing area g ; the fluid thrown non-radially from the impeller is directed radially, without disturbance or substantial change of pressure, by passing it between guideblades t presenting paths of substantially constant area. These paths of constant area are provided in all cases where deflexion of high-velocity fluid has to be effected before projection into the pressure-increasing area, as, for example, in modifications in which the impeller blades are arranged radially and discharge axially, and the increasing- area has parallel walls forming hyperboloids of revolution. The pressure-increasing area may be made divergent in two directions at right-angles, the blades of the impeller being suitably modified, and the area may be subdivided so that a compressor with multiple pressure-increasing nozzles is formed. In compressors adapted to give a compression ratio of more than 1À9, the impeller discharges into a convergent - divergent nozzle instead of directly into a divergent nozzle; this nozzle may be of the third general type. A space without guide-plates is preferably provided between the impeller and the pressure-increasing area, in which the individual streams issuing from the impeller may unite and be projected with equal velocity throughout the whole volume. A segment only of a circular compressor may be used. The substantially constant cross-sectional areas may increase slightly in the direction of flow, to compensate for frictional losses. Multi - stage compression and inter-cooling may be employed.