US2920572A - Diaphragm feed pump - Google Patents

Description

Jan. 12, 1960 P. SCHAURTE DIAPHRAGM FEED PUMP Filed Dec. 19, 1957 im a v A $2 W .1 m 2 n H D r 7 n /9 n 9 B. a 2 k 6 k l J |.|Pil. 7T6 Y a 8 u a v! n a? fi w 3 ?m /n unfin- Ala United States Patent Ofiice Patented Jan. 12, 1960 DIAPHRAGM FEED PUMP Paul Schaurte, Vaduz-Bartlegrosch, Liechtenstein Application December 19, 1957, Serial No. 703,839

Claims priority, application Germany December 22, 1956 9 Claims. (Cl. 103--44) The present invention relates to a diaphragm feed pump, and more particularly to a pump which may be used as a vacuum pump.

The prior art discloses various feed pump designs wherein the pump has at least one diaphragm, one surface of which is in direct contact with the medium to be conveyed, and which is moved back and forth by suitable driving means to fill the pump chamber either entirely or partly, depending upon the shape of the latter.

In feed pumps which have a diaphragm filling out the pump chamber entirely, such diaphragm is acted upon by revolving spherical bodies. The surface of the diaphragm facing in the direction away from the pump chamber may be under normal atmospherical pressure. In other pumps in which the diaphragm fills out the pump chamber only partly, there is usually a chamber which is closed by the other surface of the diaphragm and which usually contains an incompressible medium, for example, oil, which effects a deformation of the diaphragm by being acted upon by a plunger which is moved into a chamber containing such medium.

Other known types of feed pumps have each at least one resilient extensible diaphragm which is acted upon at one side by a gaseous or liquid medium and may be variably deformed by means of a control member which is adapted to act upon such medium. The inlet and out let conduits of such a pump which terminate into the actual pump chamber may be shut off separately, the inlet opening, for example, by the diaphragm itself. The

circumference of the diaphragm surface which is adapted to seal off the inlet conduit of such a pump is generally of a size equal to that of the circumference of the diaphragm surface which at the pressure side communicates with the medium to be conveyed. This necessarily results in considerable difiiculties in attaining a proper sealing of the pump chamber.

It is the principal object of the present invention to provide a diaphragm feed pump which overcomes the disadvantages of all similar pumps according to prior designs.

More specifically, it is an object of the present invention to provide a diaphragm feed pump in which the pump chamber will be entirely filled out by a diaphragm so that the dead space within the pump will be as small as possible. Another object of the invention is to provide such a pump in which the inlet conduit will be sealed off securely. Furthermore, it is an important object of the invention to provide a pump in which the pump chamber has a surface area as small as possible, although the capacity thereof will be as large as possible so that the diaphragm will not be subjected to any unnecessary elastic strain during the operation of the pump.

According to the present invention, these objects may be attained by making the pump chamber which is covered by the diaphragm of an annular shape, the generatrix of which consists of two circular arcs of an equal radius, and by utilizing only the central part pf the diaphragm as a sealing means for shutting off the inlet opening of the inlet conduit during the compression stroke. The sector angle of the outer arc is made of a size of about 135 and that of the inner arc is made of a size equal to the supplementary angle of the sector angle of the outer arc. In order to prevent that a part of the diaphragm might pass into the inlet opening and be caught by the edge thereof and might possibly be damaged, the present invention further proposes to cover the end of the inlet by means of a small screen and to mount this screen so that the upper side thereof will be spaced at a certain distance from the diaphragm when the latter is in its released position.

Further objects, features, and advantages of the present invention will be apparent from the following detailed description thereof, particularly when read with reference to the accompanying diagrammatic drawing of one preferred embodiment of the invention.

As illustrated in the drawing, a lower housing part 1 of the pump is provided with an annular pump chamber 2, the generatrix of which consists of two circular arcs 3 and 4, are 3 of which has a radius r while are 4 has a radius r The center of curvature 5 of the inner are 3 lies on the axis of symmetry 6 which coincides with the axis of the bore forming the inlet conduit 7. The sector angle of the outer are 4 is designated with a and the sector angle of the inner are 3 with 3. Sector angle a has a size of 135 and sector angle 5 the size of The latter is therefore equal to twice the size of the supplementary angle of the sector angle of the outer are 4. The inner end of the inlet conduit 7 is covered by a small screen 8 which may be secured, for example, by a projecting bead on the edge of the opening into pump chamber 2. Arc 4 of the generatrix starts at a point 9 and terminates into the upper surface 10 of a flange on housing part 1, not considering the rounded portion which is preferably provided between are 4 and the level surface 10. A diaphragm 13 of resilient material is then clamped between the flange on housing part 1 and a similar flange on an upper housing part 11 by means of bolts 12 so as to be disposed within the plane of surface 10.

Pump chamber 2 communicates with the outlet conduit 14 through a check valve which may consist of a plate 16 and a spring 15 acting thereon. The distance between the upper surface of plate 16 and the edge of the inlet opening in pump chamber 2 is made as small as possible.

The upper housing part 11 is filled with an incompressible fluid medium, for example, oil, which acts upon the upper surface 17 of diaphragm 13. If a plunger or the like is passed into housing part 11, the fluid therein will act upon diaphragm 13 and bend the same in the direction toward pump chamber 2. After being thus deformed to a certain extent, diaphragm 13 will first engage with screen 8 and then also with the area around the inlet opening 7a and thus seal the inlet conduit 7 completely toward the inside of pump chamber 2. If the plunger or the like is moved further in the direction toward diaphragm 13, the oil or other medium will further act upon the diaphragm so that it will be fully applied against the curved surfaces of pump chamber 2 and force the respective medium contained therein through check valve 15, 16 into the outlet conduit 14.

Instead of acting upon the oil or other incompressible medium contained within the upper housing part 11 by means of a plunger or the like as previously described, this housing part 11 may also form a chamber 18 as illustrated in the drawing, which is filled with the mentioned fluid medium and is closed by another diaphragm. 19

11 and a similar flange 21 on a cover 22 by means of bolts 23 or the like. This diaphragm 19 may then, in turn, be moved back and forth by a rod 24 in the direction as shown by arrow 25 so as to serve the function of a pump piston to press the oil or other fluid medium within chamber 18 upon diaphragm 13 so as to compress the latter into pump chamber 2.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim 1s:

1. In a pump, in combination, a base member forming part of a housing of the pump and having an end face provided with an outer annular peripheral surface located in a predetermined plane, said end face being formed with an annular channel surrounded by said annular surface and said end face having a protuberance surrounded by said channel and extending therefrom toward but terminating short of said plane so that said protuberance is spaced from and does not pass through said plane, said base member being formed with an inlet passage extending therethrough and terminating at a surface portion of said protuberance which is nearer to said plane than any other part of said protuberance, said base member also being formed with a discharge passage extending therethrough and one end of which is located substantially entirely at the deepest part of said channel at a part of an annular surface portion thereof 'which is more distant from said plane than any other surface portion of said channel, said inlet passage being substantially unobstructed and presenting substantially no resistance to the flow of fluid therethrough; a non-return valve located in said discharge passage closely adjacent to said one end thereof to restrict the direction of fluid flow in said discharge passage to flow from said channel to said discharge passage; an elastic diaphragm fixed to said annular peripheral surface of said end face and covering said channel and protuberance, said diaphragm having a rest position stretched across the space surrounded by said annular peripheral surface of said end face and located in said plane; and means acting on said diaphragm for moving the latter along a pressure stroke stretching said diaphragm into said channel to an end position covering and engaging the surface of said channel and said protuberance and freeing said diaphragm for return movement along a suction stroke back to the rest position of said diaphragm, said diaphragm during the initial part of its pressure stroke engaging said surface portion of said protuberance which is nearest to said plane and thereby closing said inlet passage, the latter being opened during the final part of the intake stroke of said diaphragm while the latter returns to its rest position, so that a portion of said diaphragm acts as an inlet valve.

2. In a pump as recited in claim 1, said annular peripheral surface and said annular channel being circular and having a common axis and said inlet passage extending along said axis.

3. In a pump as recited in claim 2, said discharge p'assage being spaced from and parallel to said inlet passage.

4. In a pump as recited in claim 1, said discharge passage being located at a substantially greater distance, in its entirety, from said plane than said surface portion of said protuberance.

5. In a pump as recited in claim 1, said protuberance having a smooth convex surface directed toward said diaphragm and merging into said channel.

6. In a pump as recited in claim 5, said channel having a smooth concave surface.

7. 'In a pump as recited in claim 6, said channel having in cross section a radius of curvature equal to the radius of curvature of said protuberance in cross section.

8. In a pump as recited in claim 1, said protuberance being located centrally with respect to said annular peripheral surface of said end face of said base member and a relatively small central portion of said diaphragm cooperating with said inlet passage to close and open the same.

9. In a pump as recited in claim 1, a screen member located in said inlet passage and carried by said protuberance closely adjacent to the surface portion thereof which is nearest to said plane to prevent the diaphragm from entering to any substantial extent into said inlet passage.

References Cited in the file of this patent UNITED STATES PATENTS 2,556,596 Perkins et al. June 12, 1951 2,575,398 Schroeder Nov. 20, 1951 FOREIGN PATENTS 305,235 Great Britain Feb. 1, 1929 489,746 Great Britain Aug. 3, 1938

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