US2028414A - Fluid displacement device - Google Patents

Description

H. sc'zl-INEIDI-:Rr 2,028,414 FLUID DISPLACEMEM- DEVICE Filed May 19, 193s 2 sheets-sheet 1 ATTORNEY.

Jan. 21, 1936A H. SCHNEIDER 2,028,414

l vFLUID DISPLACEMENT DEVICE Filed May 19, 1955 2 Sheets-Shoe?l 2 INVENTOR /vE/N/Q/cf/ 5CH/15mm BY g; U

ATTRNEY.

Patented Jan. 21, 19,36

y FLUID DISPLACEMENT DEVICE Heinrich schneider, Beloit, wis.. assignmfo Fan-- banks, Morse & Co., Chicago, Ill., a corporation of Illinois Application May 19, 1933, Serial No. 671,820

7 Claims.

This invention relates to improvements in fluid displacement devices, particularly air compressors of the so-called Roots type', for internal combustion engines and the like. More specifically, the invention is directed to improvements which minimize certain objections heretofore prevailing in compressor operation, such as, for example, suction and compression noises.

An object of the present invention is attained in an improved compressor of the type noted, in which the air inlet passages to the impeller elements are of a tortuous trend from the inlet ports to the compression chamber, whereby substantially to reduce the noise formerly incident to the suction of air through the inlet ports and passages. y

Another object is attained in an improved compressor of the type noted, in which the compression chambers and outlet passages are so formed and related in assembly as to provide a gradual pressure equalization of the air in proceeding to a receiving chamber, whereby the objectionable noises of compression are considerably lessened. l l

Further objects and advantages will appear from the following specification, and from the appended drawings, in which:

Fig. 1 is a longitudinal sectional elevation of a compressor as viewed along line I-I of Fig. 2 and Fig. 2 is a transverse sectional elevation, as taken along line 2-2 in Fig. 1.

Referring, now, to the drawings by numerals of reference, 5 designates, generally, a compressor assembly embodying improvements presently tobe described. The assembly presently exemplifying the invention includes a gear case section 1, and separate impeller housing sections 9 and I0. The housings or casing sections are preferably secured in assembly by through-bolts I2 (Fig. 2). It is, of course, understood that within practical and mechanical limits, any number. of individual impeller and housing sections and associated assemblies, such as the housing assemblies 9 and I0, may be employed in the compressor assembly. -In the application of the compressor or blower as a source of scavenging air to an internal combustion engine, for example, a part of the frame of which is shown at I3 (Fig. 2), each engine cylinder may be supplied from a single impeller section, or several cylinders may be supplied from one impeller assembly. The

angular setting of the impeller elements presently to be described, in adjacent impeller assemblies, is, in such case, preferably in accordance with the timing of the engine cycle of operation. Ex-

cept for this, the individual impeller assemblies and housings are or may be substantially alike in construction and operation. Hence, the details of only one of the impeller assemblies need be given in the following description, the same 5 reference numerals applying to like elements in each of the several displacement units.

Impeller shafts I4 and I5, disposed in spaced relation within the impeller casings 9 and I0, and extending substantially the length of the 10 compressor, are each journalled at one end in a.v portion I6 of the end Wall I1 of the case section III. vThe opposite ends I8 and I9 of shafts I4 and I5 respectively, are journalled in a wall portion 2li of gear housing 1. Driving gears 2l and 15 22, resiliently coupled through a torsion spring 23, are preferably journalled in an enlarged end wall portion 24 of the gear casing 1, substantially as illustrated in Fig. 1. The gear 2l may be coupled, either directly or indirectly, to the crank 20 shaft of the engine (not shown) to which the blower is to be applied. The gear 22 preferably engages a pinion 25 secured upon the endvl8 'of shaft I4, for driving the shaft. The shafts I4 and I5 are coupled for opposite rotation vat the 25 same rate of speed, through'like gears 26 and 21 disposed on the shaft ends I8 and I9 respectively. Referring now to Fig. 2, the casing 9 provides a pair of compression chambers 30 and 3l within which impeller elements 32 and 33 rotate, re- 30 spectively. These chambers are each of substantially cylindrical form, but are overlapping, in the sense that the central part of the displace-- ment space is common td both chambers. The impellers may be of conventional form, and are 35 preferably secured to the shafts by splined connections, as appears in Fig. 2. An air 'inlet port 34, substantially below the compression chambers,

is provided for each of the impeller assembly sections 9 and I0. A curved inlet passage 35 40 extends from the port 34 to an internal inlet port 36, supplying air to the compression chamber portions 30 and 3|. The passage is given a tortuous trend due in part to the provision of a baiiie element 38 extending within the passage, 45 adjacent the inlet port opening 34. A slotted grid or grille member 39 disposed over each inlet opening 34, serves as a means for breaking up the entering air stream. Passages 40 and 4I through portions of the dividing wall 42 between 50 the casing sections 9 and II), aid in, equalizing the quantity of air delivered to the several compression chambers. The tortuous inlet passages, equalizing passages, and the grid' member 39 collectively serve to divide and deiiect the incoming air streams to an extent materially td reduce the objectionable suction noises heretofore prevalent in compressors of the present general design, in which substantially unitary or undivided and unidirectional streams of air were drawn in by and presented td the impellers.

Outlet passages 44, 45, 48, 41 and 48, through a portion oi' the compression chamber wall opposite the wall containing the chamber inlet opening 36, communicate with a chambered compressed air receiving tting 50, which is or may be in direct communication with a chamber 5| of an engine or other machine to which the compressor is applied. When the blower is utilized to supply scavenging air to a twol-cycle engine, the chamber 5I may consist of a receiver or manifold with which is connected. the scavenging air ports. It will be noted that one group or series of passages 44 through 48, is provided for each displacement chamber 30 or 3|, and that these groups are relatively reversed in position, the passages o'f each group being graduated in area from the center to the margins of an outlet grille 5IA. This form and arrangement of passages has been found preferable, in practice. However, the passages may be of uniform size, i1 desired.

In the older prevailing forms of blowers oi the same general type, the partly-cylindrical wall 52, defining each of the compression spaces constituted by chambers 30 and 3|, extended substantially from the point X through the point Y to point Z, (Fig. 2) or through an arc usually of 180- or less, the wall portion containing the passages 41 and 48, having been heretofore unapertured, as in the presently improved construction, except for a single large opening. In the operation o'f the blower, therefore, as soon as the impeller 32 y `closed off the suction inlet to chamber 30 upon passing po'int X in the direction of rotation indicated by the arrow (Fig. 2), the compression chamber 30 was placed in direct communication with the receiver 50, and a sudden equalization of pressure in the two chambers occurred. As a result of such sudden pressure equalization, objectionable vibration and compression noises were set up. Hence, the present improved compressor serves objectively to eliminate the above noted objectionable features of operation. In the improved compressor, the wall portions 52 are extended inwardly or centrally beyond points X and Z,'vto points a and b, respectively, and hence substantially beyond a diametral plane transverse of the case, which plane, for purposes of present reference, may be considered normal to the plane common to both impeller axes, and being plane I--I of Fig. 2. The hereinabove described passages 44 to 48 are provided in the grille portion 5|A, which may be a part of the wall 52, adjacent the chamber 50. In the construction as presently modiiled, the impeller 32 cuts off the inlet near point a, the compression chamber 30 is gradually opened to the receiver chamber 5U, as the extremity of the impeller suc,

curs between the chamber 3| and receiver 58, due

to the provision of the companion group of grille openings therebetween.

While the novel features incident to only one of the displacement chambers, have been described, it will appear from the drawings (Fig. 2), that both of the chambers 30 and 3i are similarly constructed and symmetrically disposed.

The present improvements in a compressor of the type noted, serve very materially to reduce the heretofore objectionable operating noises, and further result in a more efficient and smoother running machine. It may here be indicated that a blower embodying the present improvements, is characterized by a minimum of vibration, resulting from the embodiment of principles having the effect of noise suppression; further that the improved machines are highly eilicent in service.

It is to be understood of course, that the invention is not to be limited to the presently described embodiment thereof, as alterations and modifications may be made therein without departing from the spirit and full intended scope of the invention, as dened in the appended claims.

I claim:

1. In combination in a compressor of the type noted, a case structure having a compression chamber of elliptical section, a chamber inlet port located centrally of one sidenof the chamber,

va plate across the opposite side of the chamber,

characterized by parallel, graduated discharge apertures, an inlet port in said case near one end of the elliptical chamber, means disposed across the last said port defining a plurality of parallel, iiat entering streams, a substantially curved passage formed in the case and connecting said ports, the passage extending along one end and one side of the chamber between said ports, and a baille member extending within a portion of said curved passage substantially perpendicular to the entering streams and inwardly of the case ports.

2. In combination in a compressor of Roots type, a case structure including a compression chamber therein, a chamber inlet port intermediate one side of the compression chamber, an inlet port in an outer end wall portion of said case, a passage of a tortuous trend connecting said inlet port and extending over a substantial part of one end and side of the compression chamber wall, and a grille element traversed by the impeller elements of the compressor and apertured to provide a series of graduated outlet ports defining a plurality of non-intersecting dischargeber, and a plurality of passages of substantially parallel trend and graduated area through the plate and connecting said air compression chamber and tting.

4. The combination in a compressor of Roots type, of two groups of coacting impeller elements, a casing defining an internal displacement chamber for each group of said elements and an outer chamber constituting separate air passages for supplying the groups of impeller elements, the 75 casing being provided with an inlet openings:A 'substantial size directed into one end of 'each of the air supply passages, a baille in each supply passages continuing from the baille therein, in a curved path to a zone of air introduction to the displacement chambers, said zone being located centrally of one side of the displacement chamber structure. 1

5. 'I'he combination ina including two coacting impeller elements and a casing therefor, of a perforate plate constituting a casing wall extended across the discharge side of the blower,- said plate having inner 'surface portions each adjacent to and traversed by one of the impeller elements, each of said surface portions being provided with a series of discharge passages of increasing sectional area toward the center of the plate, the plate being further provided with a central passage traversed in part by both impeller elements and of slightly greater sectional area than the remaining passages, said passages being parallel 4to each other and of a trend along the line of normal uid discharge from the blower. Y

6. The combination, in a blower of Rootstype including two coacting impeller elements and a casing therefor, of a perforate plate constituting a casing wall extended across the discharge side of the blower, said plate having inner `surface portions :each adjacent t o and traversed by one of the impeller elements, each of said surface blower of Roots type.

, v3 portions being provided with a series of discharge passagesof increasing "sectional area toward the center of the plate, the plate being further provided with a -central e traversed in part by both impeller elements and of slightly greatersectional area than the remaining passages, said passages being parallel to each other` and of a trend along the line of normal fluid discharge from the blower, the walls of the blower casing being extended laterally to form a discharge-airrecelving space, the extended walls being externally flanged .for connection to an air receiver or machine to be supplied bythe blower.

- 7. 'I'he combination, in a blower of Roots type including coacting impeller elements and a casing therefor, of an outer chamber in the casing constituting an air inlet passage Lprovided with an inlet opening of substantial size' directed into one outer end of the casing. a banle overlying the inlet opening and spaced therefrom, a grille element mounted near the inlet opening. the said inlet passage continuing from the baille to a zone of air introduction locate centrally of one side of the casing and remote rom said inlet opening,

a perforateplate bridgi the discharge side of the blower casing and having arcuate inner surface portions, one adjacent each impeller and traversed thereby, each arcuate surface portion being provided with a series of discharge passages of increasing sectional area toward the center .of the plate, said passages being substantially

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