US 3416461 A
Description (OCR text may contain errors)
Dec. 17, 1968 R. MCFARLAND 3,415461 DIAPHRAGM PUMP Fnd sept. 1, 1988 United States Patent Office Patented Dec. 17, 1968 3,416,461 DIAPHRAGM PUMP Rolland McFarland, Crystal Lake, Ill., assignor to Hills- McCanna Company, Carpentersville, Ill., a corporation of Illinois Filed Sept. 1, 1966, Ser. No. 576,704 4 Claims. (Cl. 103-150) ABSTRACT OF THE DISCLOSURE` There is disclosed a pump comprising a diaphragm having a central portion of progressively increasing thickness and an integral axially extending projection connected to an actuating member by a fitting extending over the projection and a transversely disposed pin.
The present invention relates to a novel pump structure, and more specifically to a novel diaphragm pump.
It has heretofore been proposed to provide a pump having a flexible diaphragm with means mechanically connected to the diaphragm for actuating the diaphragm in at least one direction during a pumping operation. For
example, it has been proposed to provide a diaphragm structure wherein the diaphragm is hydraulically actuated in one direction and mechanically pulled in an opposite or return direction. While certain of such heretofore proposed pumps have generally been satisfactory, diaphragm wear and leakage problems have been encountered.
An important object of the present invention is to provide a novel diaphragm pump structure wherein the diaphragm is mechanically actuated in at least one direction and wherein the diaphragm and a mechanical actuating element are constructed and connected in a manner which precludes any possibility of leakage and minimizes any possibility of diaphragm wear.
A further important object of the present invention is to provide a novel pump structure of the above described type which is of simple and economical construction which may be easily assembled.
Other objects and advantages of the present invention will be come apparent from the following description and the accompanying drawings wherein:
FIG. 1 is a partial sectional view showing a pump structure incorporating features of the present invention; and
FIG. 2 is a fragmentary partal sectional view taken generally along line 2-2 in FIG. 1.
Referring now more specifically to the drawings wherein like parts are designated by the same numerals throughout the various figures, a pump structure 10 incorporating features of the present invention comprises complementary body members 12 and 14 adapted to be detachably secured together by screws, bolts or other suitable fastening means. The body members 12 and 14 respectively present opposing annular seats 16 and 1-8. A flexible diaphragm 20 which is described more fully below is disposed with its annular margin clamped between the seats 16 and 18 and functions in combination with the body member 14 and defining a pumping chamber 22. The diaphragm also serves to separate the pumping chamber 22 from another chamber 24 in the body member 12 which accommodates hydraulic actuating fiuid as will be described below.
The body member 14 is formed with a fluid inlet 26 communicating with the pumping chamber 22 and connected through inlet passageway means 28 with an inlet conduit 30. In the embodiment shown, check valves 32 and 34 are connected in series in the passageway means 28 for preventing the reverse flow of fiuid through the passageway means. The check valves are secured in position by a suitable fitting 36.
The body means 14 is also formed with an outlet port 38 communicating with the pumping chamber 22 and with outlet passageway means 40. Additional check valves 42 and 44 are disposed in the outlet passageway means 40 for preventng reverse flow of fiuid. The check valves 42 and 44 are retained in position by a fitting 46 which is adapted to be connected with an outlet conduit 48.
The diaphragm 20 is adapted to be flexed back and forth within the chambers 22 and 24 during a pumping operation. As will be understood, movement of the diaphragm toward the left as viewed in FIG. 1 will force or pump fluid from the chamber 22 through the check valves 42 and 44 and into the outlet conduit 48.
Means are provided for hydraulically actuating the diaphragm 20 toward the left as viewed in FIG. 1 or, in other words, through its pumping stroke. As indicated above, the chamber 24, is provided for hydraulic actuating fiuid. The chamber 24 communicates with and includes a bore 50 and a reduced diameter bore 52 which are filled with hydraulic fiuid. A reservoir 54 for the hydraulic fiuid' is provided at the upper side of the body member 12 and is enclosed by a cover 56.
A valve unit 58 is disposed between the reservoir 54 and passageways 60 and 62 communicating with the chamber 24 and the bore 50. The valve unit 58 is adapted to permit hydraulic fiuid to flow from the reservoir so as completely to fill the spaces of the chamber 24, the bores 50 and 52 and the passageways 60 and 62. At the same time the valve unit 58 is constructed for permitting air to escape from these spaces whereby to insure that the spaces are completely filled with the liquid.
In order to actuate the hydraulic fiuid and thus the diaphragm 20 toward the left as viewed in FIG. 1, a mechanical piston or plunger 64 is reciprocably disposed in the bore 52. A pressure relief valve 65 is disposed between the bore 50 and the reservoir for permitting hydraulic fiuid to return to the reservoir in the event the pressure in the chamber 24 increases during the forward or working stroke of the piston to a level which may cause injury to the diaphragm. Any suitable means, not shown, may be connected with the piston 64 for reciprocating the piston. As will be understood, such piston actuating means may be made in accordance with any of a variety of heretofore known and used structures.
While the piston 64 serves to actuate the hydraulic fluid and the diaphragm toward the left, the valve unit is provided with spring means for actuating the diaphragm toward the right during the return stroke of piston 64 for minimizing any possibility of cavitation in the hydraulic actuating fiuid and for causing the diaphragm more positively to follow the reciprocating movement of the piston. In accordance with the features of the present invention the spring means is constructed and connected with the diaphragm in a manner so as to preclude leakage through the diaphragm and minimize any possibility of injury to the diaphragm while at the same time providing the desired efliciency in operation. More specifically, the spring means comprises a compression spring 66 disposed within the bore '50 and having one end seating against a fixed annular abutment 68 which in turn is supported by a snap ring 70 disposed in an annular groove or seat in the wall of the bore 50. A hollow tubular connecting rod or stem 72 is connected with the diaphragm in a manner described below and extends axially in the bore 50. The stem has an internal diameter similar to and communicates with the bore 52. Apertures 73 provide communication between the interior of the stem 72 and the bore 50. The stem 72 presents an annular fiange 74 at an end thereof opposite from the abutment 68 which flange is engaged by'the spring 66 so that the stem or connecting rod 72 is biased toward the right as viewed in FIG. l or, in other words, toward a diaphragm retracting position.
The diaphragm 20 comprises a 'body having relatively thin planar peripheral portion 76 which merges with a relatively thick central portion 78. The peripheral and central portions are integrally molded from a suitable tough resilient rubber, Synthetic rubber, plastic or other suitable material. The central and peripheral portions are preferably formed so that they provide a substantially coplanar surface facing the working or pumpiug cbarnber 22, which surface preferably covered with a laminated film or sheet material liner 80 of plastic, metal or other material inert to the fluid being pumped through the chamber 22, whereby to protect the main body of the diaphragm from the fiud.
As shown in the drawings, the relatively thick central portion 78 of the diaphragm merges with a projection 82 molded integrally therewith and from the same material as the remainder of the diphragm body, which projection extends axially rearwardly of the diaphragm or, in other words, axially into the bore 50. A transverse aperture 84 is provided through the projection 82 for accommodating a pin 86 which in turn extends through ears 88 and 90 of a fitting 92 assembled over the end of the projection 82. The fitting 92 is adapted to be connected with the stem 72.
In the embodiment shown, the fitting 92 and the stem 72 are formed with complementary threads 94 for detachably connecting the two parts together. With this constmction, it is seen that the connection between the diaphragm and the stem '72 is located entirely at one side of the main portions of the diaphragm whereby there is no possibility of leakage through the diaphragm. More precisely, the aperture which receives the pin 86 is at one side of and does not eXtend through the central portion 78 of the diaphragm. Furthermore, it will be observed that the projection 82 merges with the relatively thick portion 78 of diaphragm which gradually diminishes in thickness from adjacent the projection substantially to the peripheral portion 76, Whereby to accommodate the stresses imposed on the diaphragm by the spring means pulling on the projection 82 and to minimize any concentration of stresses during fiexing of the diaphragm and thereby promote a longer useful working life for the diaphragm. In certain instances, it is desirable to hold or otherwise secure a tubular liner 96 within the transverse aperture 84 for accommodating the connecting pin 86 and further minimizing any possibility Of injury to the diaphragm structure.
It will be noted that during assembly of the pump structure, the spring 66 and diaphragm stem 72 are dsposed within the bore 50 and secured in position by the abutment 68 and snap ring 70 prior to assembly with the diaphragm. Then the fitting 92 which has previously been connected to the diaphragm 20 is threaded into the end of the stem 72 and the peripheral portion 76 of the diaphragm is positioned against the seat 16. Prefera'bly the peripheral portion of the diaphragm is provided with annular ribs 100 which are adapted to fit within complementary grooves formed in the seat 16 for minimizing any possibility of leakage past the periphery of the diaphragm. Then the valve body member 14 is positioned against the diaphragm and the main body member 12 and is bolted or otherwise secured. If desired, additional annular ribs 102 may be provided on the diaphragrn for engaging in complementary grooves formed in the seat 18 or on the body member 14.
While a preferred embodiment of the present invention has been shown and described herein, it is obvious that many structural details may be changed without departing from the spirit and scope of the appended claims.
The invention is claimed as follows:
1. A pump comprising means including a fiexible resilient diaphragm providing a pumping chamber having an inlet and an outlet, valve means controlling fiow of fluid through said inlet and outlet, means for reciprocating said diaphragm for accomplishing a pumping action, said last named means including an element connected to said diaphragm for actuating the diaphragm in one direction, said diaphragm comprising a relatively thin flexible annular portion, an integral relatively thick central portion, an axially extending projection integral with said central portion, and means connecting said element to said projection, said means connecting said element to said projection comprises a fitting disposed over said projection, pin means extending in said projection and connected to said fitting, and complementary inter-engaging means on said fitting and said element detachably connecting said fittin g and said element.
2. A pump, as defined in claim 1, Wherein said projection has transverse aperture means therein, and said pin means extends into said aperture means.
3. A pump, as defined in claim 1 wherein said relatively thick central portion is of substantially greater radial extent than said axially extending projection and progressively decreases in thickness from adjacent a junction with said projection substantially to adjacent a junction with said relatively thin annular portion.
4. A pump, as defined in claim 1, wherein said complementary inter-engaging means comprise helical thread convolutions on said fitting and said element.
References Cited UNITED STATES PATENTS 1,711,803 5/1929 Munday 103 150 2,148,957 2/1939 Morris et al 103-150 2,267,280 12/1941 Kuhnel 230` 2,575,398 11/1951 Schroeder 103-150 2,675,758 4/1954 Hughes 103-150 3,075,468 11/1963 Eifel 103-44 WILLIAM L. FREEH, Primary Examiner.
U.S. Cl. X.R.