US2398113A - Blower - Google Patents

Description

April 9, 1946.

W. vc. PARRlsl-l 2,398,113

BLOWER Filed Sept. lO, 1945 5 Sheets-Sheet 1 @ervaar/5.

April 9, 1946. w. c. PARRISH BLOWER Filed Sept. lO, 1945 5 Sheets-Shea?I 2 iig;

April 9, 1946. w. c. PARRISH BLOWER Filed Sept. lO, 1943 5 Sheets-Sheet 3 April 9, 1946. w. c. PARRISH BLOWER Filed Sept. l0, 1943 5 Sheets-Sheet 4 manu April 9, 1946. w. c. PARRISH BLOWER Filed Sept. l0, 1943 5 Sheets-Sheet 5 M9, I y &\X X\Q44 Patented Apr. 9, 19416` UNITED s rA'rEs PATENT oFFicE" William C. Parrish,

Park Ridge, Stewart-Warner- Corporation,

corporation of Virginia Application September 10, 1943, Serial No. 501,743

2 Claims.

My invention relates generally to blowers, and more particularly to multi-stage and dualpressure axial flow blowers.

It is an object of my invention to provide an improved multi-stage or compound blower capable of delivering air under pressure with a high degree oi' eiciency.

A further object is to provide an improved unltary blower apparatus capable of delivering two separate streams of air at the same or different pressures -and rates.

A further object is to provide an improved axial flow blower apparatus'f'or supplying air for combustion and Ventilating air to an internal combustion type heater in which the blower rotors are integral, their blades concentric and driven by a common motor.

Other objects will appear from the following description, reference being had to the accompanying drawings, in which Fig.l 1 is a central longitudinal sectional view of a multi-stage blower embodying the invention;

, Fig. 2 is a fragmentary transverse sectional' view taken on the line 2 2 of Fig. 1;

Figs. 3 and 4 are fragmentary sectional views taken on the lines 3 3 and 4 4 of Fig. 2;

Fig. 5 is a longitudinal sectional view of a dual pressure blower;

Fig. 6 is a longitudinal sectional view of the blower shown in Fig. 5 as forming part of an internal combustion heater;

Fig. 7 is a fragmentary transverse sectional view taken on the line 1 1 of' Fig.4 6;

Figs. 8 and 9 are fragmentary sectional views taken on the lines 8 8 and 9 9 of Fig. 7;

Fig. 10 is a sectional view of the heater fuel nozzle shown to an enlarged scale, taken on the line i0 |0 of Fig. 6; and

Fig. 11 is an end elevational view of the nozzle structure and taken on the line I I II of Fig. 10.

The compound or multi-stage blower shown Yin Figs. 1 to 4 is adapted for use in conjunction with any apparatus in which air under pressure is required at a higher volumetric rate and at a higher pressure than can readily be obtained by fans and blowers of conventional construction. The blower comprises an 'external casing 20 which is preferably welded to a reentrant tubular lnternal casing 22 surrounding-a driving motor 24. The casings and 22 are formed to provide a streamlined annular bend `25, and the space between the external portion of the casing sheet 20 and the internal casing 22 is separated by a iiared generally cylindrical partition 26, the latter being Ill., assigner to Chicago, Ill., a

secured in position by a plurality of separators 28 which may be channel-shaped in cross section as' shown in Fig. 2, while to secure additional rigidity, similar channel-shaped separators I6 may be secured between the partition 26 land the outer casing wall 20. These separators maybe spaced around the casing at 120 intervals, and Y are preferably spot welded in position.

The outer casing 28 is provided with a plurality of inlet ports 82 for admission of air from the atmosphere or other suitable source, the air entering an annular inlet passage I4 which is formed between the outer casing wall 20 and a bellmouthed partition 36. v A plurality of curved stationary deector blades y38 are provided with ears 40 by which the blades are respectively welded'. to a ring 42 and the partition 36. Similar stationary deiiector blades 44 are secured between the partition 36 and a streamlined fairing shell 48, the latter being rigidly secured to the partition 36` by a plurality of separators. 66.

A motor mounting plate 62 is preferably welded to the internal cylindrical casing 22 and has the motor 24 secured thereto. A rotor hub 54 is seby a set screw 58, and has an inner annular flange which forms a brokenpath or labyrinth air seal between the internal casing portion 22 and the end of the hollow shell 48. The rotor is also provided with a similar outer annular seal band 62 which is recessed to form a broken path air seal between the partitions 26 and 66. The rotor has an annular rim 64fat its periphery. 'I'he rotor hub 64 is preferably in the form oi' a casting, such as a die casting, and has impeller blades 66 set between the rim 64 and the sealing band' 62, and similar blades 68 formed between the sealing band 62 and flange 66. Each ofthe blades 66, 68, has a pairof short dowel-like projections 6l at its inner end and a single such projection at its outer end, for engaging in complementary holes 69 formed in the hub ilange 66 and in the bands 62, 64. .The bands 62, 64 are sufliciently elastic that they may be sprung over the endsrof the blades and thus hold them in assembled relation.

As best shown'in Figs. 3 and 4, the rotor blades 66 are of generally airfoil section, overlap each other, and rotate in the directiony indicated by the arrow (counterclockwise, Fig. 2), so that the initialhelical motion imparted to the air by the blades 36 is utilized to improve the propulsive eilect of the blower blades. Similarly, the blades 68 which -face in a direction opposite to that of the blades 66 are adapted to imp'el the air in the direction indicated by the arrows into passageways 10 between the blades 44 which serve to stop the helical flow imparted by the blades and cause the air to now longitudinally from the blower through the annular space between the partition l0 and shell 40, this passageway being of annular bell-mouthed shape aifording the minimum of resistance to ilow of the air impelled by the blower.

.The partition sheet 00 is preferably provided with a ilange 'l2 which may be welded to a similar flange 14 formed on the outer casing wall 20, these flanges being provided with suitable bolt holes for facilitating attachment of the blower assembly to the apparatus or duct to which the air under pressureis to be supplied.

In the operation of the blower, air entering the inlet ports 02 is drawn through the annular passageway 04 and given an initial helical direction by the stationary blades 00, and has its pressure increased by the blades 00. The air nowing through the spaces between blades 00 is impelled through the annular passageway formed between the outer casing wall 20 and partition 20, and

has its direction of ilow reversed by the bend portion 20 of the casing. The air flowing to the left (Fig. l) through the passageway adjacent the inner casing Wall 22 is somewhat above atmospheric pressure, and hence of slightly increased density, thus enabling the blades 00 to operate a little more eillciently in impelling the air through the spaces between the stationary blades 44. The action of the blower is thus compound, in that two stages of compression are employed.

In the modifled form of the invention shown in Fig. 5, the blower is adapted to supply two separate streams of air under pressure. The blower comprises an outer substantially cylindrical casing 00 having inlet openings 02, an inlet partition 04 spaced from the casing 00 and secured thereto by separators 00, and a cylindrical outlet partition 00. An inner casing 00 surrounding the motor 24 is spaced from the partition 04 by relatively long separators 02. A fairing shell 04 is secured to the outlet partition 00 by separators 00. The rotor of the blower is constructed in substantially the same manner as above described with reference to Figs. 1 to 4, the only material diiferences being in the relative lengths of the blades 00 and 00, and that the guide vanes 00 and 44 are both located downstream with resct to the rotor, although with suitable changes in the construction both sets of guide vanes could be located on the upstream side of the rotor. Reference characters corresponding to those of Figs. l to 4 have therefore been applied to the similar parts in Fig. 5.

In the operation of the blowerl shown in Fig. 5, the air stream A entering the inlet ports 02, has its velocity oi' ilow increased by the blades 00 and its tendency toward helical flow retarded by the blades I0. The air stream B entering the space between the partition 04 and inner casing 00 is similarly acted upon by the rotor blades 00, and has its rotary component of velocity substantially removed by the stationary blades 44. The blower may be designed to have the air stream A discharge therefrom at high velocity and pressure while the aix stream B may be discharged at a lower pressure and velocity, or vice versa, or the design may be such that the volumetric tiow and pressure of the two streams is substantially equal. By virtue of the labyrinth seal elected by the hub 00 and the band 02, there will be but relatively slight leakage! from One of the air streams to the other, so that under circumstances where such slight leakage would not be disadvantageous the two streams might be of different gases.

The invention is illustrated by a further modification shown in Figs. 6 to ll, inclusive, in which a blower is illustrated as forming a part of a heater of the hermetically sealed or internal combustion type. The general structure of the blower is similar to that shown in Fig. 5, and corresponding reference characters have therefore been applied to the similar parts. In this embodiment of the invention, the air stream A constitutes the combustion air supply for the heater while they air stream B constitutes the ventilating air supply. The rotor hub in Fig. 6 is illustrated as comprising a bushing |00 to which a ilanged member |02 is secured by a peening operation. In other respects the structural details of the blower portion of the heater are the same as in the previously described embodiments.

The heater is illustrated as comprising a combustion chamber |04 formed by a cylindrical wall |00, one end of which is substantially closed by a partly torroidal shaped end wall |00 which may be welded tothe cylindrical wall |00. The partition 00 has a pair of openings formed therein to receive the bell-mouthed inlet ends of a pair oi' fabricated conduits I |0 which project diametrically through the cylindrical wall |00 of the combustion chamber and is T-shaped to provide an outlet portion ||2. The flow of the air stream A through the conduit ||0 to the opening in the axial outlet portion ||2 is facilitated by the provision of a plurality of baiiles I0.

The opening in the outlet portion I2 is closely adjacent the end of a spray nozzle ||0 which is suitably secured in a supporting ring 20, the latter preferably being welded to the end wall |00 at the center thereof. Fuel is supplied to the nozzle ||0 through a conduit |22 which is secured to an elbow iltting |24 by means of a clamping fitting |20. The nozzle I I0 is detachably secured to the elbow |24, as by threading, and has a fine wire'mesh strainer |00 for inhibiting the clogging of the Jet orifice in the nozzle ||0.

The mixture of fuel supplied through the conduit |22 and air supplied through the ducts ||0, is ignited preferably by means 0f an electrical igniter illustrated as comprising a shell |02 threaded in a fitting |04 which is welded to the end wall |00. The igniter includes a coiled resistance wire |00, one end of which is grounded to the shell |32 and the other end ot which is electrically connected to a conductor I 00. The products of combustion ilow vfrom the combustion chamber to a heat exchanger |40, through the air passageways of which the air stream B is propelled by the blower. 'I'he details of construction of a heater of the type generally described are more particularly shown in my copending application, Serial No. 494,155, nled July 10, 1943.

An improved nozzle structure is, however, disclosed in this application, and it is best illustrated in Figs. 10 and l1, wherein it will appear that the elbow iltting |24 is secured to the end wall |00 oi' the combustion chamber by cap screws |42 extending through lugs |44 formed on the elbow fitting 24, and threaded into sockets |40 which may be welded to the end wall |00. The elbow fitting |24 seals against the ring |20, a suitable gasket |40 being provided to prevent leakage at this point. The nozzle is formed by a tip |00 which is threaded in the elbow iitting l |24 and is internally threaded to receive an atomizing plug |52 which has a separate head portion |54 provided with grooves |56 which impart a rotary component of motion to the fuel as it flows toward and outwardly fromv a jet aperture |58. A fitting |60 supporting the screen |30 is also threaded in the nozzle tip I 50. By virtue of this arrangement the nozzle may readily be removed for inspection and any servicing which may be necessary, by unscrewing the cap screws |42. i

A protective cap may be provided over the igniter |34 and elbow fitting |24, this cap comprising a generally cylindrical wall |62 which may be welded to the end wall |08 of the combustion chamber, and a cover |64 which is secured in place by a plurality of screws |66, it being understood that access to the cap screws |42 may be obtained by removal of the blower assembly and the removal of the cap I 64. To

facilitate this removal, it will be understood that the separators 86 may be welded only to the partition 84 and* thus may be longitudinally slidable with respect to the outer casing 80.

In operation of the heater, assuming that fuel is being supplied through the conduit |22 at a regulated pressure, and that the igniter |36 and motor are energized, the air stream A will strike 1' the fuel spray formed by the nozzle IIB, and some of this fuel will iind its way into the fitting |34 where it will be vaporized and ignited, causing ignition of the turbulently flowing mixture of fuel and air adjacent the end wall |06. 'I'he burning fuel and products of combustion flow through the combustion chamber |04 into the heat exchanger |40 in which the air stream B is heated. The air stream B also flows around the combustion chamber, deriving heat therefrom, and preventing the cylindrical wall |06 or end wall |08 thereof from becoming overheated.

The heater may be provided with the usual electrical thermostatic controls. It will be clear that lassuming that the fuel pressure is well regulated, and that the heater is operating at constant altitude, thefuel air ratio will be maintained relatively constant since the blower operates at constant speed to supply the combustion air stream A to the heater uniformly. Likewise the ratio of combustion air to Ventilating air is maintained relatively constant since both of these air streams are derived from a common power source. The heat output of the heater will therefore be relatively constant.

While I have shown and described particu lar embodiments of my invention, it will be apparent that numerous variations and modifications thereof may be made without departing from the underlying principles of the invention. I therefore desire, by the following claims, to include within the scope of my invention all such variations and modifications by which substan- .tially the results of my invention may be obtained through the use of substantially the same or equivalent means.

I claim:

1. A blower comprising an outer cylindrical casing wall and an inner cylindrical casing wall, said walls being joined at one end to form a 180 bend, a cylindrical partition held in spaced relation between said casing walls, said casing walls and partition providing a substantially continuous passageway, a motor secured within the inner casing wall, a rotor driven b y said motor, said rotor having two sets of impeller blades of opposite pitch, one of said sets rotating across the outer portion of said passageway and operating to impel air in one direction, the other set of blades rotating across the inner portion of said passageway and impelling air therethrough in the opposite direction, said rotor having a hub forming substantially a continuation of the'inner casing wall, an annular ring secured to said hub by the inner set of blades and forming substantially a continuation of the cylindrical partition, and an outer band surrounding the outer set of blades and acting as a support therefor.

2. In a blower structure, the combination of a motor, an inner cylindricalcasing wall surrounding said motor, a cylindrical outer casing wall, a cylindrical partition located intermediate said casing walls, a rotor driven by said motor,

said rotor having a hub portion having a generally Vcylindrical surface of substantially the same diameter as said inner casing wall, a band of' substantially the same diameter as said partition, a plurality of impeller blades secured between said band and said rotor hub, and a plurality of impeller blades projecting outwardly from said band sov as to impel air through the passageway formed between the outer casing and the partition.

WILLIAM C. PARRISH.

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