US3601507A

US3601507A - Compact fluid compressor

Info

Publication number: US3601507A
Application number: US853298A
Authority: US
Inventors: Dwight E Harris
Original assignee: Rotron Inc
Current assignee: Rotron Inc
Priority date: 1969-08-27
Filing date: 1969-08-27
Publication date: 1971-08-24
Anticipated expiration: 1988-08-24
Also published as: GB1287557A; JPS4935284B1; FR2059269A5; DE7031944U; DE2042356A1

Abstract

A regenerative compressor in accordance with the invention described herein comprises a stator and a rotor coaxial therewith to form a motor. Concentric to the motor and between its ends is a compressor chamber having inlet and exhaust openings. A compressor wheel is mounted on the rotor and projects into the compressor chamber for providing a high compression output in a limited space.

Description

United States Patent I H113,601,507

[72] lnventor Dwight EJ-larr's {56] ReferencesCited 2 1 I N ggfig UNITED STATES PATENTS a 2,768,583 10/1956 Richardetal. 3l0/67X fig g 'g'gg? 2,772,046 11/1956 Sh0mphe..... 310/67X 1 2,926,838 3 1960 VanRijn 3lO/67X [73] Assignee Rotron Incorporated Woodstock, N.Y. Primary Examiner- Robert M. Walker Attorney-Brumbaugh, Graves, Donohue & Raymond [54] COMPACT FLUID COMPRESSOR 7 clmmsz Drawmg ABSTRACT: A regenerative compressor in accordance with' [52] US. Cl 417/354, the invention described herein comprises a stator and a rotor 310/67 coaxial therewith to form a motor. Concentric to the motor [5 1] Int. Cl ..F04b 17/00, and between its ends is a compressor chamber having inlet and H02k 7/00 exhaust openings. A compressor wheel is mounted on the [50] Field of Search n 417/354, rotor and projects into the compressor chamber for providing 423; 310/67 21 high compression output ina limited space.

1 l -45 ;I1l I fa I l I f i /& 6Z-. 44 6 0 5 6 1 7'37 2 22 l 772 PATENTED AUG24 197:

INVENTOR. DWIGHT E. HARP/8 M%M M his ATTORNEYS.

V COMPACT FLUID COMPRESSOR '5 In many applications involving the use of electric motors or electronic components, it is necessary to remove the heat generated in order to maintain the operating life or charac-- teristics of the unit. To accomplish this, it is usual to provide an electric fan that will remove the heat generated and provide the v above-described advantages. Generally, however, space is at a premium and the size of the fan must be kept to a minimum in order to be compatible with the installation.

Another application requiring compact exhaust fans is the removal of wet or corrosive vapors, such as given ofi by the chemical solutions employed in certain types of duplicating or printing machines. In addition to the space problem, it is a necessity in the design of fans for this type of application, that the motor and blower structure be protected from the harmful efl'ects of the vapors.

In all of the above-described applications still another factor must be considered, i.e., the fan must provide a high compression in order to remove as much of the heat and vapors as possible. Compact tube axial fans and centrifugal compressors are available, but these units do not provide a high enough output for many requirements nor are such units resistant to the harmful effects of excessive moisture orcorrosive vapors.

Where high outputs are required, designers have frequently employed regenerative compressors. However, presently available regenerative compressors are too large for many environments, conventionally, consisting of a shaft extending axially from an electric motor and carrying an impeller that projectsinto a compressor chamber spaced from the motor. The overall dimensions, particularly in the axial direction, are thus often too large to be satisfactorily utilized in the environments described above. These devices also present somestructural difficulties that add to their complexity and cost.

It is an object of this invention, therefore, to provide a fan capable of a high compression and having a relatively small axial length so as to be usable where space is at a premium and a high output is required.

It is another object of this invention to provide a fan that is capable of exhausting corrosive or wet vapors while preventing detrimental effect to the motor.

It is still another object of this invention to provide a regenerative compressor of the type described above wherein the problems associated with mounting the impeller to the shaft are alleviated and wherein the heat of the motor is dissipated in the airstream driven by the impeller.

Briefly described, this invention comprises a cup-shaped rotor assembly mounted for rotation about a stator assembly and wherein the impeller wheel is mounted directly to the rotor assembly and projects radially therefrom at a point located between the ends of the motor. An annular compressor chamber is also located between the ends of the motor and is coaxial therewith, so as to receive the impeller wheel. By this arrangement, the size of the fan is significantly reduced and motor heat is dissipated into the airstream exhausted by the compressor.

If the motor is to be used to exhaust corrosive or wet vapors, the motor assembly may be encapsulated in a suitable plastic that prevents the detrimental effect of these vapors on the motor.

For a better understanding of the present invention, reference is made to the following specification and the accompanying drawings, in which: I

. FIG. 1 is an elevation view of a regenerative compressor in accordance with the invention; and

FIG. 2 is a cross-sectional view of the compressor shown in FIG. 1, taken along the line 2 -2.

Referring to the drawings, there is disclosed (FIG. 2) acentrally disposed stator assembly surrounded by a cup-shaped rotor assembly 12 to form a motor carried in a housing 56, 58. Located coaxially with the motor is an annular substantially closed compressor chamber 16 of generally toroidal configuration that receives a suitable impeller assembly 18 secured directly to the rotor assembly 12.

, connected to an alternating current source in any conventional fashion to provide the revolving magnetic field. A flanged member 26 includes a collar portion 28 received in the aperture of the stator assembly 10 and a flange 30 projecting radially from the collar portion adjacent one end of the stator assembly. At the outer edge of the flange 30, a plurality of slots 32 are formed for a purpose to be fully explained hereinafter.

Molded about the stator assembly 10 is a plastic material 24 that may, if the fan is to be utilized to exhaust wet or corrosive vapors, completely encapsulate the statorand provide a protective coating for the core 20. Otherwise, the plastic 24 need not encapsulate the outside diameter of the core 20. During the molding operation, plastic will flow through the openings 32 to establish an interlock for the member 26. Along the faces of the flange 30 the plastic stops a distance from the end to leave a projecting rim 34 around the circumference of the stator assembly. The purpose of this rim will be fully explained hereinafter.

The rotor assembly 12 is a generally cup-shaped arrangement including a flat base portion 36 supporting the annular laminations 38 and an end ring 40. Laminations 38 project axially from the outer periphery of the base portion 36 so as to cooperate with the core 20 and provide an electric motor. Also projecting axially from the'inner face of the base portion 36 is a central boss member 42, the purpose of which will be explained hereinafter.

As mentioned previously, the impeller assembly 18 is carried on the rotor assembly 12 and comprises an annular mounting ring 44 that is fixedly secured to the outerperiphery of the rotor assembly at a point intermediate the ends' thereof. As shown in FIG. 2, the ring 44 defines a fractional part of the innermost surface of the compressor chamber 16. Thus the ring 44 completes the chamber 16 defined by the housing. A plurality of regenerative compressor blades 46, which may be curved or planar, project radially from the outer surface of the ring member 44 and extend into the compressor chamber'1 6. The blades 46 serve to compress gases which enter the chamber 16 as they are forced to move in a generally circulatory mannerthrough a substantial portion of the chamber 16. The blades 46extend to the outermost surface that defines the chamber 16 as shown in FIG. 2. It should be apparent that this arrangement reduces the axial length of the compressor to that of the electric motor and also eliminates the problems of attaching the impeller to a narrow cylindrical shaft. Motor heat is readily dissipated since the fan blades 46 and ring member 44 are made of a metal or plastic'having good thermal conductivity, and thus provide a good heat conducting path from the motor to the chamber 16 where the heat is exhausted with the air.

Preferably, the impeller assembly 18 should be secured to the rotor'assembly 12 in a very rigid manner due to the high forces acting thereon. The accomplishment of such a joint is difficult when the fan is to be extremely small because of the lightweight materials being utilized However, the joint described herein provides the desired rigidity while allowing use of the materials desired. The end of the rotor base 36 is cut to form a step 37 extending around its periphery so that two surfaces are provided. Depending inwardly from the ring 44 is a lip portion 45 that is adapted to butt against thetwo surfaces provided by the step 37. Since the ring 44 extends along the laminations 38, three distinct areas of contact'between the ring and rotor assembly are provided and a rigid joint is achieved. The left-hand portion of the ring may be'extended, as at 47, under the chamber 16 to provide a greater contact area between the ring and the rotor assembly and an improved fluid seal.

When assembled in their operative relationship, the boss member 42 projects into the central aperture of the stator assembly 10. Rotatably supporting the rotor assembly 12 is a shaft 48 fixedly carried by the boss member 32 and extending through the remaining portion of the central aperture. A'suitaretaining washer 54 is snapped over the end of the shaft 48- also in a manner that is well known in the art.

A preferred form of housing includes a first housing portion 56 adapted to be secured to the stator assembly and has a cup shaped portion 58 that may be integrally molded with a semicircular wall portion 60 forming a portion of the toroidal chamber 16. The end face of the cup-shaped portion 58 includes an annular opening therethrough having an undercut lip portion 62 projecting inwardly around the periphery of the opening. When assembled, the rim 34 on the stator assembly will be received in the lip 62 and adhesively secured thereto. A removable end cap 64 may be placed in the open end of the central opening through the stator assembly to seal the motor.

Also included as part of the housing is a back wall portion 66 that is generally cup-shaped and complementary to the chamber wall 60. When assembled, e.g., by suitable clips 68, the housing and the compressor chamber 16 are formed. The housing thus defines at least three sides of an annular compression chamber. As shown by FIG. 1, this chamber is of substantially constant cross-sectional area.

The compressor chamber includes an inlet 70 and an outlet 72, between which is located a stripper (not shown) projecting inwardly from the chamber wall 60 at a point between the inlet and exhaust opening so as to guide the air through the exhaust opening. Any convenient shape of inlet and outlet may be employed, to suit the particular application and environment. In the illustrated embodiment, the inlet includes a generally tubular coupling element for connection to a conduit, and the outlet comprises simply an opening in the wall 60 of the compressor chamber. Mounting lugs 74 may also be provided to secure the fan to a support member.

It should be apparent from the preceding description that a narrow fan capable of a high delivery is provided wherein the heat dissipation and impeller mounting problems are solved.

tive embodiment of this invention, various modifications will occur to those skilled in the art to which this invention pertains. Accordingly, it is not desired to limit the invention to the exact features disclosed, but to encompass all such modifications.

I claim:

1. A regenerative compressor comprising a centrally disposed stator assembly, a rotor assembly surrounding said stator assembly and operatively associated therewith to form an electric motor, a housing secured to said stator, said housing partially defining an annular and substantially closed compression chamber surrounding said rotor assembly and disposed substantially between the ends thereof, said chamber Additionally, it should be noted that if the stator windings 20 are completely encapsulated in plastic, the fan may be used to exhaust wet or corrosive vapor.

While in the foregoing there has been disclosed an illustra- 3. A regenerative compressor according to claim 1 wherein said housing defines at least three sides of said chamber.

4. A regenerative compressor according to claim 1 wherein said ring defines a fractional part of the innermost surface of said chamber and the remainder of said chamber is defined by said housing.

5. A regenerative compressor according to claim 4 wherein said chamber is generally toroidal in shape.

6.'A regenerative compressor according to claim 1 wherein said chamber is of substantially constant cross-sectional area and said regenerative compressor blades extend to the outermost surface that defines said chamber.

7. A regenerative compressor according to claim 1 wherein said rotor assembly includes a cup-shaped member surround ing the stator assembly, a portion of which forms a step around its periphery, and said ring includes a lip which butts against two surfaces of said step to provide a rigid joint between said ring and said rotor assembly.

Claims

1. A regenerative compressor comprising a cEntrally disposed stator assembly, a rotor assembly surrounding said stator assembly and operatively associated therewith to form an electric motor, a housing secured to said stator, said housing partially defining an annular and substantially closed compression chamber surrounding said rotor assembly and disposed substantially between the ends thereof, said chamber being concentric with said stator assembly and said rotor assembly, a ring rigidly secured to said rotor defining at least a part of the innermost surface of said chamber, a plurality of regenerative compressor blades depending from said ring and extending into said chamber whereby gases which enter said chamber are compressed as they are forced to move through a substantial portion thereof in a circulatory manner.

2. A regenerative compressor according to claim 1 wherein said ring is fixedly secured to said rotor assembly at a point intermediate the ends thereof.

3. A regenerative compressor according to claim 1 wherein said housing defines at least three sides of said chamber.

6. A regenerative compressor according to claim 1 wherein said chamber is of substantially constant cross-sectional area and said regenerative compressor blades extend to the outermost surface that defines said chamber.

7. A regenerative compressor according to claim 1 wherein said rotor assembly includes a cup-shaped member surrounding the stator assembly, a portion of which forms a step around its periphery, and said ring includes a lip which butts against two surfaces of said step to provide a rigid joint between said ring and said rotor assembly.