Domed cover for pump head

Abstract

A cover for the head of a pump defines one or more cavities with radiused corners between the upper and side surfaces of the cavity so as to form a domed chamber.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This claims the benefit of U.S. Provisional Patent Application No. 60/602,836 filed Aug. 19, 2004.

STATEMENT CONCERNING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE INVENTION

This invention relates to pumps (compressors or vacuum pumps), and in particular to a cover for the intake and/or exhaust heads of such pumps.

BACKGROUND OF THE INVENTION

Pumps such as compressors or vacuum pumps compress a gas, very often air, into an exhaust chamber that is separated from the compression chamber by a valve, very often a flapper valve. Such pumps suck the gas past a valve into the compression chamber. The exhaust chamber may be contained in a head of the pump and the head may also contain an intake chamber, through which air is drawn into the compression chamber past a one way valve, that also may be a flapper valve. Alternatively, intake air may enter the compression chamber through the piston itself, that may be provided with a flapper valve permitting one way flow of the gas into the compression chamber. In that case, the head may define a single continuous chamber, without a divider wall separating into two chambers.

A head of such a pump may have a valve plate cast integrally with it, or it may be separate, or it may have a cover cast integrally with it, or the cover may be separate. Separate covers typically presented a generally flat interior surface closing off the top of the head, and if the head had two chambers (intake and exhaust), sealed the two chambers from one another. Typically the head is provided with at least one port per chamber that the head defines, the port(s) typically being provided in the side walls of the head.

Noise can be an important characteristic of pumps, for example if the pump is used in interior living spaces, like if the pump is used for medical equipment or other equipment that is used indoors around people. Flat covers for open topped heads, which serve the purpose of closing off the top of the head, can result in resonation of the noises present in each head chamber. This invention addresses that problem.

SUMMARY OF THE INVENTION

The present invention provides a domed cover for closing the open top of a head of a pump. The domed cover has a mounting surface that mounts to the head at the level of the open top of the head to close off the head. The domed cover defines one or more chambers that extend upwardly from the mounting surface to increase the volume of the head chamber that the cover closes. The upwardly extending walls of the cover chamber transition to orthogonally extending upper surfaces of the cover with continuous unbroken radii to provide a continuous unbroken surface without discontinuities or sharp angles between the surfaces of the chamber defined by the cover as those surfaces change in direction by 180 degrees. Preferably, the side surfaces are also joined to one another with radiused corners so as to provide a swooping transition between them without discontinuities or sharp corners against which sound waves can impinge. Such a cover has no sharp corners and preferably the radii that transition the surfaces that extend in orthogonal directions are relatively large, for example in the range of 0.02 to 1.50 inches, preferably 0.09 to 0.65 inches.

Such a domed cover can be made to define two domed chambers, and can be used as such whether the head to which it is assembled defines two chambers or only one. If the head defines two chambers, then the cover has a mounting surface between the two chambers that it defines, that may or may not seal off the two chambers of the head. If the two chamber cover is used with a single chamber head, with no wall dividing the single chamber of the head, the single chamber confining a space that is effectively as big as the two chambers combined if the head had two chambers, the cover still provides noise attenuation, and can provide a degree of attenuation that is greater than if the cover were made with a single concavity or chamber spanning the entire volume of the head.

The foregoing and other objects and advantages of the invention will appear in the detailed description which follows. In the description, reference is made to the accompanying drawings which illustrate a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a cover of the invention assembled to a head:

FIG. 2 is an end plan view of the cover and head of FIG. 1;

FIG. 3 is a top perspective view of the cover alone;

FIG. 3A is a cross-sectional view from the plane of the line 3A-3A of FIG. 2 of the cover and head of FIGS. 1-2;

FIG. 3B is a cross-sectional view from the plane of the line 3B-3B of FIG. 3A of the cover and head of FIGS. 1-3A;

FIG. 4 is a top plan view of the cover alone:

FIG. 5 is a bottom plan view of the cover:

FIG. 6 is a cross sectional view from the plane of the line 6-6 of FIG. 4:

FIG. 7 is a cross sectional view from the plane of the line 7-7 of FIG. 4:

FIG. 8 is a cross sectional view from the plane of the line 8-8 of FIG. 5: and

FIG. 9 is a cross sectional view from the plane of the line 9-9 of FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a cover 10 of the invention is illustrated assembled to a head 12. As shown in FIG. 2a, the head 12 may define two chambers 13 and 14, in which one chamber may be an intake chamber and the other may be an exhaust chamber for the pump, or, as shown in FIGS. 1-3B, the head 12 may define a single chamber which spans approximately the same area as the two chambers combined. In the case of the single chamber 15, this chamber would typically be an exhaust chamber, receiving compressed gas from the compression (or vacuum) chamber of the pump, and in such case the compression (or vacuum) chamber may receive intake air through a valve in the piston of the pump. As is well known. The head 12 typically has at least one port 16, and if it has two chambers it will typically have two ports, one on each side of the wall (not shown) that divides the two chambers. The dividing wall of the head would be right below the surface 28 (FIG. 3B) and an airtight seal would be formed between the wall and the surface 28. If the head has a single chamber as illustrated in FIGS. 1-3B, there is no dividing wall beneath the surface 28.

The head 12 also defines a mounting surface 18 that the cover 10 mounting surface 20 seals against and abuts. An O-ring, a gasket, or sealant may be provided between the mounting surfaces 18 and 20 of the respective head 12 and cover 10 to provide to seal.

The cover 10 is secured to the head 12 with bolts or other fasteners extending through the corner holes 22. In addition, as best shown in FIG. 5, the cover 10 may be provided with locator holes 24, and locator pins 13 (FIG. 3B) can be provided extending above the mounting surface 18 of the head 12 that fit in the locating holes 24, which as shown in FIG. 6, are blind bores. The cover 10 mounting surface 20 extends around the periphery of the cover 10 in generally the same shape as the mounting surface 18 of the head 12. If the head has a wall that divides it into two chambers, the top of the dividing wall would provide the part of the mounting surface 20 that seals against the bridging portion 28 of the mounting surface 20 of the cover 10.

The cover 10 defines two chambers or cavities 30 and 32. Each cavity 30, 32 extends inwardly from the mounting surface 20 with side wall portions that are at approximately a right angle to the mounting surface 20, or they may be at other than a right angle to the mounting surface 20. The side wall portions are identified by “S”. The side wall portions S transition to an inner wall portion I, that is at approximately 90 degrees to each adjacent side wall portion, through a transition zone T that is defined with a radius greater than 0 (not a right angle) and preferably a relatively large radius to provide a gentle unbroken continuous slope between the side wall portions S and the inner wall portion I of each cavity 30 and 32. The surfaces S, T and I thereby form continuous unbroken and smooth surfaces for the interiors of the cavities 30 and 32. The radius of the transition surfaces T is in the range of 0.02 to 1.50 inches, and preferably in the range of 0.09 to 0.65 inches.

Forming the interior surfaces of the cavities 30 and 32 creates a domed structure in the cavities 30 and 32 that has the effect of attenuating noise in the chamber or chambers defined by the head 12 during operation of the pump. Cover 10 has two chambers 30 and 32 and can be used with either a one chamber (as illustrated in FIGS. 1-3B) or a two chamber head. If the cover 10 were made with a single chamber spanning substantially the same area as the two chambers 30 and 32 combined, then such a cover could only be used with a single chamber head such as that shown in FIG. 2b unless the head was intended to be converted to a single chamber head by the use of the single chamber cover.

In addition, the side surfaces are joined to one another with similarly radiused corners C (FIG. 5), so that there are no sharp corners joining the side surfaces S to one another. The radii of the corners that join the side wall surfaces to one another are also in the range of 0.02 to 1.5 inches, preferably in the range of 0.09 to 0.65 inches.

A preferred embodiment of the invention has been described in considerable detail. Many modifications and variations to the preferred embodiment described will be apparent to a person of ordinary skill in the art. Therefore, the invention should not be limited to the embodiment described.

Claims

1. A cover for a head of a pump, the head defining at least one chamber for receiving a gas expelled from a pumping chamber of the pump, the head having a mounting surface against which the cover is mounted, comprising:

a mounting surface of the cover for meeting with and mounting against the mounting surface of the head;

at least one chamber extending inwardly from the mounting surface of the cover, the chamber opening to the chamber defined by the head and the chamber of the cover having side wall portions extending from the mounting surface of the cover and an inner wall portion that spans the side wall portions, the side wall portions being joined to the inner wall portions by transition zones that are radiused so as to form a domed transition between the side wall portions and the inner wall portion of the cover chamber surfaces.

2. A cover as claimed in claim 1, further comprising a second chamber extending inwardly from the mounting surface of the cover, the chamber opening to the chamber defined by the head and the chamber of the cover having side wall portions extending from the mounting surface of the cover and an inner wall portion that spans the side wall portions, the side wall portions being joined to the inner wall portion by transition zones that are radiused so as to form a domed transition between the side wall portions and the inner wall portion of the cover chamber surfaces.

3. A cover as claimed in claim 2, wherein the cover is adapted to fit a head that defines a single chamber that spans both chambers of the cover.

4. A cover as claimed in claim 1, wherein the radii of the transition surfaces are in the range of 0.02 to 1.5 inches.

5. A cover as claimed in claim 1, wherein the radii of the transition surfaces are in the range of 0.09 to 0.65 inches.

6. A cover as claimed in claim 1, wherein radiused corners join the side wall portions to one another.

7. A cover as claimed in claim 1, wherein the radii of the corners are in the range of 0.02 to 1.5 inches.

8. A cover as claimed in claim 1, wherein the radii of the corners are in the range of 0.09 to 0.65 inches.