US3395853A - Vortex compressor - Google Patents

Description

1968 G. ZOEHFELD 3,395,853

VORTEX COMPRESSOR Filed Dec. 29, 1965 IV ///A INVENTOR. GUNTHER ZOEHFELD is ATTORNEYS 3,395,853 VORTEX CGMPRESSOR Gunther Zoehfeld, West Hurley, N.Y., assignor to Rotron Manufacturing Company, Inc., Woodstock, N.Y., a corporation of New York Filed Dec. 29, 1965, Ser. No. 517,288 Claims. (Cl. Z3ll--22) ,NcJW...

ABSTRACT OF THE DISCLOSURE The present invention relates to compressors of the regenerative 0r vortex type, and more particularly, to means for regulating the output pressure of such devices so as to increase their operating efficiency.

Vortex compressors have been used as pumps for liquids, vapor mixtures, and gases, such as air, generally in applications where a high-pressure head and moderate flow are required. They have also been employed as effective vacuum sources for vacuum cleaners, control systems, etc.

Upon rotation of the impeller in a vortex compressor, the centrifugal force imparted to the fluid establishes a pressure differential between the fluid at the root of the impeller blade, closer to the axis of rotation, and the tip of the blade. This difference in fluid pressure causes a vortex current, which is basically perpendicular to the plane of rotation of the impeller. Increasing vortex currents naturally cause an increase in the internal friction of the pump and a concurrent decrease in pump efiiciency.

Heretofore, when it was desired to operate a vortex compressor at a particular point on its pressure versus throughput characteristic, the general practice has been to throttle or restrict the throughput. However, the power consumption of this type of compressor increases as throughput decreases and a reduction in throughput caused a corresponding reduction in efiiciency.

Various attempts have been made in the past to overcome the above difficulties. In one arrangement control of the operating conditions is effected by recirculating part of the output of the compressor back into the intake manifold. While this approach is effective to some degree, it has a significant disadvantage inasmuch as the recirculation continually adds energy to the flow and overheating can result under certain conditions.

In accordance with the present invention, the aboveindicated difficulties in vortex compressor control are overcome by providing a valve to bypass or bleed off some of the pressurized fluid to the exterior of the compressor. By such means, the power consumption of the vortex compressor for providing a particular output pressure is significantly less than that resulting from the use of throttling devices. Moreover, since no recirculation of the bypassed fluid occurs, the overheating problem encountered by prior art bleed valve arrangements is avoided. When the compressor is used as a pump, the bleed valve is located on the high pressure side; when used as a vacuum source, it is placed on the low pressure side.

The vortex compressor of the invention comprises an impeller, input and output chambers, and input and output manifolds adapted to cooperate with their corresponding chambers. The compressor is interchangeably usable as a pump or vacuum source and is formed with bypass bores extending from the input and output chambers to the outside surface. Bleed valves are mounted in either or both of the bores, as desired, to control the fluid flow between the compressor chambers and the ambient atmosphere. Preferably, such a valve comprises two spaced support columns extending from the interior surface of the compressor for supporting a conical member coaxially with and partially within the bore. The conical member is axially movable and by adjusting its position within the bore, the area of the annular passage formed between the bore and the conical member may be varied, thereby providing means for controlling the flow through the bypass bore which, in turn, regulates the pressure at the input and/ or output manifolds.

For a more complete understanding of the invention, reference may be had to the following detailed description taken in conjunction with the figures of the accompanying drawings, in which:

FIGURE 1 is a view in vertical section through a vortex compressor according to the invention showing the bleed valve; the section through the compressor being taken along the line 1-1 of FIGURE 2;

FIGURE 2 is a sectional view taken along the line 22 of FIGURE 1;

FIGURE 3 is a view in section of the bleed valve, partially broken away and taken along the line 33 of FIGURE 2; and

FIGURE 4 is a view in partial cross-section illustrating another form of bleed valve.

Referring to FIGURES l and 2 of the drawings, a vortex compressor 10 has a housing with three basic supporting elements: a cover plate 11, a frame 12 and a cup-shaped casing 13 surrounding the rear or impeller end of the member 12 and secured thereto by press fitting or other suitable means.

The frame 12 comprises a circular web 14 at its lefthand end as seen in the drawing, an outer cylindrical member 15, and an inner cylindrical member 16; both members 15 and 16 extending concentrically from the right-hand surface of the web 14 and preferably integral therewith. Defined between the two cylindrical members 15 and 16 is an annular chamber 18, whereas the interior surface of the inner member 16 defines a central cylindrical cavity 20.

Formed in the left-hand surface of the web 14, opposite the chamber 18, is a toroidal channel 22 of semicircular cross-section. The channel 22 forms a stator. which is adapted to co-operate with a series of blades 25 provided on an impeller member 26 in a manner described later.

As shown in FIGURE 1, the cover plate 11 is secured to the frame 12 by machine screws 27 which pass through the plate 11 and are anchored within the cylindrical member 16 of the frame 12. The annular channel 18 is actually divided into separate intake and outlet chambers 18a and 1812, respectively, by means of two baflie plates 28 and 29, each secured to the cylindrical members 15 and 16 (FIGURE 2).

Fluid from an intake port 31 flows into the annular chamber half 18a and then, by means of an opening (not shown) provided in the web 14, into the stator channel 22 of the compressor. The opening 33 communicates with the annular chamber half 1811 and receives the high pressure discharge from the impeller 26. From the chamber half 18b, the pressurized fluid is discharged through the output port 35 provided in the cover plate 11.

Preferably, suitable mufflers 37 and perforated retaining plates 38 are disposed within the annular chamber 18 to suppress noise, as disclosed in copending application Ser. No. 517,412, filed Dec. 29, 1965, by Dwight E. Harris and Gunther Zoehfeld for Regenerative Compressors with Integral Mufiiers, and assigned to the present assignee.

A shaft 40 is axially situated within the cavity and rotatably mounted in bearings 41 and 42, the bearing 41 being supported in the web 14 of the frame 12 and the bearing 42 in the cover plate 11. Thrust rings 44, fixed to the shaft 40, are adapted to cooperate with and engage their respective bearings and 41 to permit axial loads imparted to the shaft 40 to be absorbed by the journal bearings 41 and 42.

A motor 49, within the cavity 20, includes a rotor fixed to the shaft 40 and a stator 51 secured to the interior surface of the cylindrical member 16 by any appropriate means. The motor 49 drives the shaft 49 which extends beyond the web 14 and supports the impeller 26 within the cup-shaped member 13. The impeller 26 is secured to the shaft 40 and held in a fixed position by means of a key 55 simultaneously engaging a slot in impeller 26 and a slot in shaft 40, and held in place by screw 54.

The blade members 25 of the impeller 26 are disposed adjacent to and adapted to cooperate with the fixed stator channel 22. Upon rotation of the shaft 40 by the motor 49, the impeller 26 develops vortex currents as it rotates inasmuch as the pressure at the tip of each blade 25 is greater than the pressure developed at its root. The rotating impeller 26 draws fluid, for example air, in through the intake port 31 into the chamber 18a. The pressure of the fluid is thereafter raised by the rotary action of the impeller 26 with respect to the stator and directed out through the opening 33 into the annular chamber 18b from where it is discharged through the output port 35. Thus a low pressure is established at the intake port 31 and a high pressure at the outlet 35.

A bleed valve 57, shown in FIGURE 2 to be an integral part of the compressor 10, is disposed, for example, within the output chamber 18b adjacent a cylindrical bore 58 extending through the cover plate 11 between the chamber 18b and the exterior of the compressor 10. The valve 57 is carried by tWo spaced support columns 60 and 61 integrally formed on the cover plate 11, which extend into the confines of the cavity 18b. A flat plate 63, anchored by machine screws 64 to the free ends of the support columns 60 and 61, fixedly holds threaded bolt member 66 which is aligned with the axis of the bore 58 and has its free end extending into the bore. A conical valve element 70 has its external surface 71 tapering inwardly into the bore 58 to cooperate with the corresponding flared surface 73 at the inner end of the bore which provides the valve seat.

The annular passage 74 defined between the surfaces 71 and 73 permits the pressurized fluid to be bypassed from the chamber 18b without passing through the manifold 35 thereby reducing the output pressure delivered through the manifold 35. The position of the member 70 within the bore 58 may be varied by inserting a screw driver into a slot 75 provided in the blunted forward end of the conical member 70 and rotating the member 70, advancing or retracting it along the axis defined by the threaded member 66. If the conical member 70 is advanced into the bore 58, the area of the annular passage 74 will be reduced and the output pressure of the compressor 10 increased; whereas if the member 70 is retracted, the output pressure will be reduced.

Another embodiment of a bleed valve according to the invention is shown in FIGURE 4 and includes a conical member 70 having a conical surface 71, a plate 63, and a threaded member 66 substantially identical with corresponding members of FIGURE 3. Here, however, the bore 58' formed in the cover plate 11 is provided with a threaded internal surface adapted to engage a thread 81 formed on the outer surface of a tubular insert member 84. The member 84, also formed with a bore 86, is provided with a frusto-conical surface 87 at its rear end and which flares inwardly into the bore 86 and a slot in its forward end, which, by means of a screw driver, facilitates its rotation thereby and enables it to be advanced or retracted in relation to the member 70. If the insert member 84 is moved toward the conical surface 71, the flow area of the annular passage 74 defined between the surfaces 71 and 87 will be reduced; whereas if it is moved away from the member 70, the annular passage area will be increased and the output pressure at the output port 35 reduced.

If the bleed valve is to be used in the inlet chamber 18a, the same valve structure as shown in FIGURES 3 or 4 may be similarly mounted adjacent the opening 90 provided in the cover plate 11. When not used, the opening 90 would be sealed by a suitable plug.

As will be recognized, the bleed valve allows an adjustable portion of the compressor throughput to be dissipated into the ambient atmosphere. Thus, to achieve a desired operating point on the delivered pressure versus throughput characteristic for the compressor, the unit can be designed to provide the desired pressure at whatever volume delivery rate results in lowest power consumption. Then, the bleed valve can be adjusted to allow a portion of the throughput to escape and leave the desired fluid flow at the output. Insofar as the compressor is concerned, it is delivering fluid at optimum efiiciency for the desired pressure. The bleed valve in the inlet chamber provides a similar control when the compressor is used as a vacuum source. The trimming action provided by the bleed valve enables proper system performances regardless of fluid density or power frequency to the motor at a particular location and compensates for varying degrees of fluid leakage in the system with which it is used.

In comparison, conventional throttling controls reduce the compressor throughput, moving the operating point to a higher pressure value on the characteristic and consequently increasing power consumption. Moreover, the heating problems encountered in recirculating bleed systems, such as are commonly used to minimize compressor stall, are avoided.

While there is shown and described preferred embodiments of the invention, it is to be understood that it is not limited to the precise elements of their construction. For example, automatically controlled bleed valves may be provided and could, for example, be operated by a motor or other mechanical connections. Therefore, the invention as described is merely exemplary and should be limited only as set forth in the claims.

I claim:

1. A vortex compressor comprising a housing, rotor and stator means in said housing, means for driving said rotor with respect to said stator means to increase the pressure of fluid supplied thereto, fluid inlet and outlet chambers in said housing communicating with said stator to, respectively, supply fluid at a relatively low pressure to said rotor and stator means and extract fluid at a higher pressure therefrom, inlet and outlet ports communicating respectively with said inlet and outlet chambers, said housing being formed with a bore extending from the exterior of the compressor to one of said chambers, and valve means being insertable in said bore for defining a passage in relation to said bore, said valve means being contoured to reduce the passage flow area in a first position and increase said area in a second position thereby controlling the operational characteristics of the compressor.

2. A vortex compressor accordin to claim 1 wherein said valve means includes a valve element having a tapering external surface extending into said bore.

3. A vortex compressor according to claim 2 including an insert member in threaded engagement with said housing, said insert member defining said bore which is cooperable with said valve element to define said passage.

4. A vortex compressor according to claim 3 wherein said valve means includes two spaced column members formed on said housing, a plate secured to the free ends of said columns, and an elongated threaded member extending into said bore, said valve element being in threaded engagement with said elongated member and movable along an axis defined by said elongated member.

5. A vortex compressor according to claim 1 wherein said housing is formed with an additional bore extending from the exterior of the compressor to the other of said chambers, and further including valve means insertable in said additional bore to vary the passage flow area of said bore.

References Cited UNITED STATES PATENTS 1,481,358 1/1924 DWyer 230-25 Schlachter 103-96 Gruss 230-125 Albright 230-22 Hofer 23022 Wright 103-97 Wheatley 230-22 Hunter 230-22 Hruby 103-97 Nilsson 230-46 FRED C. MATTERN, JR., Primary Examiner.

W. J. KRAUSS, Assistant Examiner.

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