US 3125033 A
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March 17, 1964 J. H. A. MARYE 3,125,033
RECIPROCATING DIAPHRAGM PUMPS Filed May 29, 1961 2 Sheets-Sheet 1 1 i A5 A i i l 1 1.1 1.3 115 1.7
I v T DEA/v f/mvri T x9 31! i BY i MM I ATTORNEYS L March 17, 1964 J. H. A. MARYEQ RECIPROCATING DIAPHRAGM PUMPS- 2 Sheets-Sheet 2 Filed May 29, 1961 ATTORIJEYJ United States Patent l 3,125,633 RECIERQCATING DIAIGM PUMPS Jean Henri Albert Marys, Elancourt, France, assiguor to Etablissements A. Guiot, Paris, France, a society of France Fiied May 29, 1961, Ser. N 113,473 Claims priority, application France June 17, 1960 3 Ciaims. (Q1. 103-150) The present invention relates to reciprocating diaphragm pumps and more especially to pumps for feeding fuel to internal combustion engines, and provided with diaphragm pulsation absorbers. Such absorbers comprises a pulsation absorbing chamber in direct communication with the liquid delivery conduit of the pump at the point thereof where it starts from the pump, this pulsation absorbing chamber having one wall thereof formed by a flexible diaphragm forming a deformable partition between this pulsation absorbing chamber and a closed chamber filled with a compressible fluid, the walls of said closed chamber other than said flexible diaphragm being rigid.
The object of this invention is to improve the eiriciency of such pumps. For this purpose, according to the present invention, the mean pressure of the compressible fluid imprisoned in the closed chamber (that is to say the value of this pressure when the pump is not working) is higher than atmospheric pressure.
A preferred embodiment of the present invention will be hereinafter described with reference to the appended drawings, given merely by way of example, and in which,
FIG. 1 is a diagrammatic vertical sectional view of a pump made according to this invention.
FIGS. 2 and 3 show on an enlarged scale the diaphragm pulsator of the pump of FIG. 1 in two successive positions of the mounting of said pulsator.
FIG. 4 shows curves illustrating the operation and advantages of the pump according to these inventions.
The pump shown by the drawing comprises a pumping chamber 1 one wall of which consist of a diaphragm 2 the central portion of which is given a reciprocating movement. Chamber 1 has its communication with an inlet conduit 3 controlled by an inlet valve 4 and its communication with a delivery conduit 5 controlled by an outlet valve 6. The direction of flow of fuel, or other liquid is indicated by the arrows.
Diaphragm 2 is actuated against the action of a spring '7, by a rod 8 operated by an oscillating lever 9. This lever 9 is itself actuated by a push piece or a cam operated through any conventional means (not shown). Advantageously, as shown, a lever 10 is provided for manually operating diaphragm 2.
The diaphragm pulsator comprises a closed chamber 11 separated by a flexible diaphragm 12 from a pulsation absorbing chamber 13. Delivery conduit 5 starts from a point of said pulsation absorbing chamber 13 located between outlet valve 6 and flexible diaphragm 12.
According to the present invention, the mean value of the pressure in closed chamber 11 is higher than atmospheric pressure, this mean pressure being, as above stated, the pressure existing in chamber 11 when the pump is not in operation.
There may be provided on the rigid wall of chamber 11 a connection for pumping air into said chamber to the desired pressure when the pulsator is already mounted on the body 14 of the pump.
According to the construction illustrated by FIGS. 2 and 3, the rigid portion of chamber 11 is a dome 15 having an annular edge 15a and the pump body 14 is provided with an annular groove 16 of substantial depth a running along the edge 17 of pulsation absorbing chamber 13. The Whole is arranged in such manner that edge 15a fits about 3,125,033 Patented Mar. 17., 1964 2 edge 17 with a slight annular play such that diaphragm 12, of a thickness just a little greater than said play, can be pinched between the edge 15a of dome 15 and the bottom of groove 16. Advantageously, these elements are of revolution about a common axis which is for instance vertical, as shown by the drawing.
Thus, after diaphragm 12 has been placed to rest across the edge 17 of body 14, dome 15 being applied on this diaphragm (FIG. 2), when dome 15 is pushed down so that its edge 15:: pinches diaphragm 12 between itself and the bottom of groove 16, the mass of air initially imprisoned between dome 15 and diaphragm 12 is compressed, and the value of the pressure of this compressed air mass is the above mentioned mean pressure, diaphragm 12 being deformed by the pressure so that its convexity is turned toward the inside of chamber 13 as shown by FIG. 3.
FIG. 4 shows curves obtained by plotting in ordinates the values of the flow rate D of the pump (measured in liters per hour with a counter pressure of 200 grs. per square centimeter in the delivery conduit of the pump) and in abscissas the mean pressure p (in kg. per square cm.) in chamber 11, for a frequency of 1500 pulsations per minute. Curve A was obtained with a diaphragm of great flexibility and curve B with a diaphragm of lower flexibility, these two diaphragms being made of the same material but thesecond one having a thickness equal to twice that of the first one.
These curves show that the delivery flow rate first in creases when the pressure in chamber 11 increases until this pressure is close to the static pressure of the pump shown in dot-and-dash lines at abcissa 1.3. Then when the pressure p in chamber 11 increases above this value, the delivery flow rate decreases. It should be reminded that th static pressure is the pressure existing in delivery conduit 5 when this conduit is closed. It results from these curves that to have a high flow rate of the pump (86.5 liters per hour as indicated at D for curve A, and 79.5 liters per hour as indicated at D for curve B, as il lustrated by FIG. 4), the means pressure p in chamber 11 should range from 1.1 to 1.7 kg. per sq. cm., that is to say, from to of the static pressure of the pump (which is 1.3 kg. per sq. cm.).
Curves A and B also show that it is of interest to have a diaphragm 12 as flexible as possible. In view of the maximum dimensions that can be accepted for the pump and of the resistance of the diaphragm to mechanical and chemical actions, a suitable choice must be made for the mean pressure in chamber 11 and the diameter of the diaphragm. As a matter of fact, the flexibility of this diaphragm decreases when the mean pressure increases and when the diameter of the diaphragm decreases. However, taking into account the indications of the curves of FIG. 4, it is possible to determine the best possible characteristics for the pulsator. As a rule, the mean pressure in chamber 11 will be chosen lower than the static pressure of the pump.
It is possible to provide on the suction part of pump a pulsator which may be either without diaphragm as shown by FIG. 1 where this pulsator consists of an air dome 18 disposed at the top of suction chamber 19, or with a diaphragm, in which case the mean pressure should be adjusted to a value higher than atmospheric pressure.
In a general manner, while I have, in the above'description, disclosed what I deem to be practical and eificient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.
What 1 claim is:
1. A liquid pump which comprises, in combination, a casing, an oscillating diaphragm mounted in said casing to form therewith a pump chamber, inlet and outlet valves carried by said casing to control the inflow of liquid to said chamber and its outflow therefrom, respectively, a delivery conduit for the outflow of liquid from said outlet valve, said casing comprising means, adjoining said outlet valve on the downstream side thereof, forming a pulsation absorbing chamber in direct communication with said delivery conduit, said pulsation absorbing chamber having a rigid edge extending along a closed line located in a plane, and said pulsation absorbing chamber being located on one side of said plane, means forming a third chamber located on the other side of said plane from said pulsation absorbing chamber, said third mentioned chamber having a single opening limited by a rigid edge fitting against said first mentioned edge with a slight play, a flexible diaphragm of a thickness just a little greater than said play and the periphery of which follows said edges on the outside thereof, one of said means being provided, along said rigid edge thereof and on the outside of said edge, with a groove accommodating with a gastight fit the whole of the edge of the other of said means and of said diaphragm periphery extending over said last mentioned edge, said groove having a depth, in a direction perpendicular to said plane, such that, with said last mentioned edge and said diaphragm periphery fully engaged in said groove, the closed space between said diaphragm and the inner face of said second mentioned means is under a pressure greater than atmospheric pressure and said diaphragm bulges into said pulsation absorbing chamher.
2. A liquid pump which comprises, in combination, a casing, an oscillating diaphragm mounted in said casing to form therewith a pumping chamber, inlet and outlet valve means carried by said casing to control the inflow of liquid to said chamber and its outflow therefrom, delivery conduit means for the outflow of liquid from said outlet valve means, means adjoining said outlet valve means to form a pulsation absorbing chamber downstream of said outlet valve means and in direct communication With said delivery conduit means, said pulsation absorbing chamber having a rigid edge extending along a closed line, the Wall of said pulsation absorbing chamber forming a deep groove running along said edge on the outside of said line, a flexible diaphragm extending across said edge and said groove so as to form one wall of said pulsation absorbing chamber, means forming a closed chamber limiting by said last mentioned diaphragm on the other side thereof from said pulsation absorbing chamber, said last mentioned means comprising a rigid dome having an edge shaped to fit into said groove and wedge said diaphragm therein and a mass of compressible fluid imprisoned in said closed chamber and filling it, said mass of compressible fluid consisting of a gas filling the space between said dome and said flexible diaphragm whereby, when said dome is forced into said groove, said gas is compressed above atmospheric pressure 3. A pump according to claim 2 wherein said closed line is a circle.
References Cited in the file of this patent UNITED STATES PATENTS 2,283,439 Herman May 19, 1942 2,318,128 Tabb May 4, 1943 2,929,333 Harry Mar. 22, 1960 FOREIGN PATENTS 1,925 Great Britain 1861