US 2764097 A
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Description (OCR text may contain errors)
P 25, 1956 H. BROWNE 2,764,097
Filed March 4, 1953 FIG 2 I INVENTOR. LINDSAY H. BROWNE d iwm,
ATTORNEYS ite States Patent PUMP Lindsay H. Browne, Westport, Conn. Appiication March 4, 1953, Serial No. 340,274 6 Claims. Cl. 10344 This invention relates to. pumps and, particularly, to pumps for delivering elastic fiuids, either gases or vapors, at high pressures.
In my application Serial No. 169,840, filed June 23, 1950, there is disclosed a pump suitable for the delivery of liquids at extremely high pressures, this pump being particularly designed for the pumping of liquids carrying abrasive materials, corrosive liquids, liquids requiring the maintenance of sterile conditions, etc. Said pump involves the use of a rubber pulsator to provide separation between an operating liquid and the liquid being pumped. The liquid being pumped flows through a chamber exterior to the pulsator, but in operation the minimum volume of this chamber is substantial and, consequently, the pump is not adapted for the pumping of elastic fluids against high pressure heads.
It is the broad object of the present invention to adapt the type of pump described in said application for the pumping of elastic fluids at high pressures. As in the case of the liquid pump, the elastic fluids may be of such nature or involve such requirements as to make their pumping either difiicult or impossible with known types of pumps. For example, and as will appear hereafter, the fluids pumped may be highly corrosive, may possibly contain either solid or liquid constituents in the form of dust or droplets, or may require complete isolation either for the preservation of sterile condition or because the fluids may be highly dangerous. In accordance with the invention an operating liquid is isolated from the fluid being pumped by a flexible, elastic member, but the chamber through which the elastic fluid passes is reduced during operation to a very small volume with the consequent result that high pressures may be attained. Consistently with this, the separating diaphragm is of such nature that it is not destroyed during operation.
The foregoing general object as well as subsidiary objects particularly relating to details of construction and operation will become apparent from the following description, read in conjunction with the accompanying drawing, in which Figure 1 is a fragmentary sectional view showing certain operating parts of the pump similar to those disclosed in my prior application; and
Figure 2 is an enlarged vertical section showing details of those elements of the pump particularly concerned in the attainment of the desired results.
in the following description the fluid which is being pumped will be, for convenience, referred to as gas but itwill be understood that this term embraces elastic fluids, including vapors, and possibly including solid particles in the form of dust, liquid droplets in the form of mist, or even mixtures of liquid and elastic fluid in which the liquid may even constitute the major volumetric content of the mixture. In fact, it will be evident that the pump may handle substantially incompressible liquids, and the liquids might well contain solid materials in suspension. The invention, however, is particularly adapted for the handling of fluids exhibiting elastic properties.
Referring first to Figure l, the mechanically operating parts of the pump may be essentially those disclosed in my prior application referred to above, and in fact, the pump of that application is, by simple external changes, transformed into the pump forming the subject matter of the present application. Reference may be made to said application for various details not herein disclosed. The pump comprises a casing 2 arranged to provide a reservoir for oil 0 which serves both as the operating liquid and for lubrication of the mechanical parts. A member 4- secured in the housing provides a cylinder bore 6 in which there reciprocates a piston 8 urged outwardly by a spring, it) acting against a head 12 on the piston against a roller 14 carried by the lower end of a lever 16 pivoted at 18 and provided with a follower roller 20 operable by a cam 22' which is driven through gearing 24 from a motor operated shaft 26. The cylinder in which the piston reciprocatesis inclined downwardly and outwardly of the casing, as indicated in Figure 1, and is completely submerged in the oil 0 in the reservoir. A plurality of radial openings 28 in the cylinder wall communicate with an internal annular groove 30 which is arranged to be uncovered by the piston 8 when the piston moves in its outward stroke under the action of spring 10. As in the case of the pump described in my prior application, this provides free communication between the cylinder 6 and the reservoir upon each outward stroke of the piston and provides for the removal by gravity of any air which might be present in the cylinder. There is also provided by this arrangement the existence of a definite quantity of liquid within the cylinder at the beginning of each inward stroke of the piston at the time the piston closes off the annular port 30. A fixed liquid displacement is thus assured on each stroke. The lower end of the member 4 is threaded and a coupling member 32 is secured thereto with the interposition of an 0 ring 34, the coupling member 32 serving to secure the cylinder 4 in position in the housing. This coupling member is provided with a bore in alignment with the cylinder bore 6 and tapped into its outer end is a pipe 36 which may be of any convenient length.
To the outer end of pipe 36 there is secured a disc 38 having a bore 43 communicating with the pipe. A second disc 40 is secured to the disc 38 by screws 42. The disc 38 is provided with a chamber 44 communicating with the bore 43 and delimited by a wall which is partially radial at 45 and partially conical at 46. The disc 40 is provided with a similar chamber 47 which is simi-. is partially radial at 48:
larly delimited by a wall which and partially conical at 49.
Between the two discs there is located a diaphragm of special construction consisting of a metal disc 50 provided; with a tapered peripheral edge to which is bonded a rubber annulus 52 which is formed at its periphery with effectively, an O ring. The dia-. is of a quite stifi type and func-.
a bead 54 constituting, phragrn thus constituted tions as hereafter described.
The beaded periphery 54 has an important function providing sealing of the chambers 44 and 47. Since: very high pressures are involved in the use of this pump,
the forces tending to separate the discs 38 and 40 are large and must be resisted by the screws 42. If ordinarypacking were used between the discs, the screws 42 would normally require tightening to such extent as to impose operating; there being no substantial pre-- While rubber is herein referred to with respect to the material of the portion 52 of the diaphragm, and will be hereafter referred to in connection with the inlet and outlet valves, it will be understood that this term is used in a broad sense to include both natural and synthetic rubbers including synthetic rubbers of silicone type. The particular types of rubber used depend upon the materials which are being handled and the nature of the operating oil. In case operation is required at high temperatures, silicone types of rubbers are desirable.
The inlet pipe 56 for the gas is tapped into the coupling 58 which is secured to the disc 40 by bolts (not illustrated) there being provided an O ring for packing. In a bore communicating with the chamber 47 and with the passage through the member 58 there is located a valve element 60 of a type found particularly desirable in the handling of gases. This valve is formed of rubber and at its inner end is conically tapered as indicated and is provided with a central bore which is also conically tapered toward the inner end of the valve. To sustain the valve against collapse a portion of its bore is lined with a metallic tube indicated at 62. The valve is provided with a transverse slit 64 communicating with the tapered end of its bore, and providing a valve of the Bunsen type.
In operation, when the valve 60 is subject to a pressure on its right hand side, as viewed in Figure 2, exceeding that on its left hand side, the material yields to open the slit 64 and permit flow. When the pressure gradient is reversed, the pressure tends to tightly engage the portions of the rubber on opposite sides of the slit 64 providing a tight closure with compression toward the right resisted by the relatively massive body of rubber. Closure takes place even if small solid particles may be present in the slit at the time of closure, and it has been found that this type of valve is highly satisfactory during the high pressure operation involved in the pump.
The outlet pipe 66 is tapped into the coupling 68 which, like that at 58, is secured to the disc 40 by screws, not shown. A bore in the coupling 68 receives a valve 70 which is the same as valve 60 but oppositely directed to permit flow to the pipe 66. A sustaining tube 72 is provided within the bore of the valve and fits within an opening in disc 40 communicating with the chamber 47.
A relief valve is provided comprising a housing 74 which has a bored projection 76 threaded into an opening 78 communicating with the passage in the coupling 32. A valve 86 which is spring urged toward seating position normally closes the bore 76. Oil passing through the valve escapes through pipe 84 which returns it to the reservoir in the housing 2. As will appear, the valve 80 is urged toward its seat with sufficient force to withstand opening under the pressures against which pumping occurs, but opening takes place to relieve excessive pressure after arresting of movement of the diaphragm.
While a single unit pump has been indicated, it will be understood that a plurality of operating units may be provided operated by several cams on the shaft of cam 22, the operation being for the various units out of phase to provide better continuity of delivery. Under these circumstances, the pipes 56 of the several units may be provided from a common manifold, and likewise delivery from the pipes 66 may be to a common manifold.
The pump is particularly designed for the handling of gases which enter the pump at substantial pressure. Assuming this, the operation may be described, considering initially that the piston 8 is in its extreme outer position, toward the left in Figure 2, uncovering the port 30. Under this condition, assuming that the pressure in pipe 56 is substantially in excess of atmospheric pressure and sufficient to fully deflect the diaphragm, the disc 50 of the diaphragm will lie in its extreme left hand position against the radial wall portion 45 of the chamber 44. At the same time, the pressure at the right of the diaphragm will force the rubber portion 52 thereof into tight engagement with the conical portion 46 of the chamber wall. In moving from the central position illustrated in Figure 2 to this left hand position, the rubber portion 52 of the diaphragm will be in slight radial tension, i. e. this portion of the diaphragm will be tensioned between its peripheral bead 54 and the periphery of the metal disc 59. The oil in the cylinder 6 will now be under substantially atmospheric pressure by reason of free communication with the oil in the reservoir, the level of which is above that of the uppermost port 28. Because of the sloping arrangement of the cylinder, any air which may have initially existed in the cylinder will be permitted free escape through the ports 28.
As the piston llll moves inwardly it will close the port 30 entrapping below it a definite volume of oil. As it moves downwardly and to the right, this oil is forced into the chamber 44 displacing the diaphragm to the right until the metal disc 56) thereof engages flatwise the radial portion 48 of the wall of chamber 47. When this occurs, the rubber portion 52 of the diaphragm will engage flatwise the conical portion 49 of the chamber wall, the rubber portion 52 of the diaphragm being again under slight radial tension between the bead 54 and the periphery of the metal disc 50. Under these conditions, the residual volume between the diaphragm and the valves and will be a minimum consisting substantially solely of the space exterior to the conical end of valve 60 and the bore within the valve 70. This volume is only a small fraction of the volume between the same elements when the diaphragm is in its left hand or suction position. Consequently, a high compression ratio is attainable.
It will be noted that the metal disc 50 subtends the entire area within which there occur the valve openings. The disc itself is sufficiently thick to wihstand the highest pressures to be encountered without distortion, and it will be evident that the construction is such that when the metal disc engages the portion 48 of the right hand chamber wall there is no space into which the rubber portion 52 of the diaphragm might be extruded. Rubber, while elastic and distortable, is substantially incompressible, and it will be evident that despite the existence of high pressures the rubber will not be subjected to any forces which might tend to its destruction. Its range of flexing is small and likewise its radial extension under tension is small.
The valve remains closed, being seated with a spring force suflicient to withstand the discharge pressure, until the diaphragm is arrested in its right hand position. Since the oil forced by the piston can no longer displace the diaphragm, its pressure will build up sufiiciently to unseat the valve 80 to permit escape of the excess oil volume. However, the apparatus is initially designed so that there is very little movement of the piston following the arresting of the diaphragm and, accordingly, the oil which is driven past the valve 80 may be only very small in amount on each piston stroke. It is desirable, however, to provide some excess oil displacement by the piston to insure that on each stroke the diaphragm is moved fully. On the reverse stroke of the piston the diaphragm is subjected to expansion of the residual gas at its right hand side and when the pressure drops below that of the inlet pressure the valve 60 will open permitting gas to enter the chamber 47 and driving the diaphragm to its left hand position in contact with the wall portions 45 and 46 of the chamber 44. Finally, the port 30 is uncovered by the piston and the parts are restored to the positions initially described above.
It will be evident from the foregoing that there is provided a pump capable of delivering fluid at high pressures and without destruction of the diaphragm or the valves involved in the operation. The elastic fluid is completely isolated from the operating liquid and the parts with which the elastic fluid contacts may be made of suitable materials to resist corrosion and abrasion. Rubber is particularly effective in resisting abrasion and is, therefore, desirably used for the inlet and outlet valves through under other conditions other types of check valves may here be used. It Will be evident that the construction is such that all of the parts in contact With the elastic fluid may be readily dismantled and cleaned and subjected to sterilization. Accordingly, the pump may be used under the various conditions described above. Pressures as high as 1200 pounds per square inch have been delivered by this pump.
What is claimed is:
1. A pump comprising a housing having an opening therein, a diaphragm extending across said opening to divide it into an operating chamber and a pumping chamber, means providing inlet and discharge passages communicating with said pumping chamber, check valves in said passages for controlling flow therethrough, a passage communicating With said operating chamber, and means for cyclically forcing liquid into, and releasing liquid from, said operating chamber through the last mentioned passage, said diaphragm comprising a rigid central disc and an elastic annular outer portion secured to said central disc and held at its perimeter in said housing, said chamber being delimited by Walls, each partially radial at its central portion over an area corresponding to the area of said disc and partially conical at its peripheral portion over an area corresponding to the area of said annular outer portion of the diaphragm, the surfaces of said disc and annular outer portion of the diaphragm merging smoothly and continously with the result that at their junction they meet the junction region of said central and peripheral positions of each Wall substantially simultaneously as the diaphragm is flexed thereagainst, the Walls of said chambers having openings to the aforementioned passages in said central portions thereofagainst which said disc engages.
2. A pump according to claim 1 in Which the disc and annular outer portion of the diaphragm have bonded interengaging taper and socket portions.
3. A pump according to claim 2 in which the tapered portion extends around the periphery of the disc and the socket portion extends around the inner edge of the annular outer portion of the diaphragm.
4. A pump comprising a housing having an opening therein, a diaphragm extending across said opening to divide it into an operating chamber and a pumping chamber, means providing inlet and discharge passages communicating with said pumping chamber, check valves in said passages for controlling flow therethrough, a passage communicating With said operating chamber, and means for cyclically forcing liquid into, and releasing liquid from, said operating chamber through the last mentioned passage, said diaphragm comprising a rigid central disc and an elastic annular outer portion secured to said central disc and held at its perimeter in said housing, said chambers being delimited by walls, each Wall at its central portion having a surface corresponding at least to the outermost portion of the disc surface over the area corresponding thereto and being approximately conical at its peripheral portion over an area corersponding to the area of said annular outer portion of the diaphragm, the surfaces of said disc and annular outer portion of the diaphgram merging smoothly and continuously With the result that at their junction they meet the junction region of said central and peripheral portions of each Wall substantially simultaneously as the diaphragm is flexed thereagainst, the Walls of said chambers having openings to the aforementioned passages in said central portions thereof against which said disc engages.
5. A pump according to claim 4 in Which the disc and annular outer portion of the diaphragm have bonded interengaging taper and socket portions.
6. A pump according to claim 5 in which the tapered portion extends around the periphery of the disc and the socket portion extends around the inner edge of the annular outer portion of the diaphragm.
References Cited in the file of this patent UNITED STATES PATENTS 1,995,611 Hapgood Mar. 26, 1935 2,079,858 Horton May 11, 1937 2,221,071 Barfod Nov. 12, 1940 2,372,360 Cornelius Mar. 27, 1945 2,564,693 Hornbostel Aug. 21, 1951 2,653,552 Geeraert Sept. 29, 1953 2,711,134 Hughes June 21, 1955 FOREIGN PATENTS 6,657 Great Britain of 1894 500,498 Belgium Jan. 31, 1951