US3301189A - Variable capacity pump - Google Patents

Description

Jan. 31, 1967 KLJNG VARIABLE CAPACITY PUMP 2 Sheets-Sheet 1' Filed April 22, 1964 FIG.I

INVENTOR. NELSON G. KLI NG ATTORNEYS Jan. 31, 1967 N. G, KUNG 3,301,189

VARIABLE CAPACITY PUMP Filed April 22, 1964 2 Sheets-Sheet 2 INVENTOR. NELSON G. KLING F566 7 BYTWWGRQ- ATTORNEYS Patented Jan. 31, 1967 3,301,189 VARIABLE CAPACITY PUMP Nelson G. Kling, Ringwood, N..l., assignor to Technicon Chromatography Corporation, Chauncey, N.Y., a corporation of New York Filed Apr. 22, 1964, Ser. No. 361,726 Claims. (Cl. 103-38) This invention relates to improved pumps which are particularly adaptable to the pumping of relatively small quantities of liquid.

An object of the invention is the provision of pumps for the pumping of very accurately metered quantities of liquid.

Another object of the invention is the provision of pumps of design and construction which make possible the convenient assembly and disassembly thereof.

A further object of the invention is the provision of pumps of sturdy and dependable design and construction which require only the use of readily available components of proven dependability to furnish long periods of accurate and maintenance-free operation.

Another object of the invention is the provision of variable delivery, reciprocating pumps of conveniently adjustable stroke which utilize relatively slow, constant speed drive motors to minimize reduction gearing requirements, while insuring constant pump delivery at each stroke adjustment.

A further object of the invention is the provision of pumps as above which are particularly adaptable for use in conjunction with chromatographic columns for amino acid determinations.

The above and other objects and advantages of the invention are believed made clear by the following detailed description thereof taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side plan view, with parts in section, of the pump assembly of the invention;

FIG. 2 is a bottom plan view, with parts in section, and portions cut away for purposes of illustration, of the pump assembly of the invention;

FIG. 3 is a vertical sectional view taken along lines 33 of FIG. 2;

FIG. 4 is an enlarged sectional view of one of the valve assemblies of the pump of the invention;

FIG. 5 is an enlarged top plan view with parts in section and portions cut away for purposes of illustration, of one of the sealing assemblies of the pump of the invention;

FIG. 6 is an end view of the stroke-adjusting mechanism taken in the direction of line 66 of FIG. 1; and

FIG. 7 is a vertical sectional view similar to FIG. 3 of a modified form of the pump of the invention.

Referring now to the drawings, and especially FIGS. 1 and 2, the pump comprises a main housing 10 which includes a hollow interior portion 12 formed as shown therewithin, and integral support leg portions 14- ex tending therefrom for the support of the said pump on any convenient surface. A drive motor 16 is positioned as shown atop the said housing by a heat insulated mounting plate 18, preferably but not necessarily of phenolic composition, positioned therebetween. Attachment screws 20 function to secure the said motor to the said mounting plate, and similar, but non-illustrated, attachment screws function to in turn secure the said mounting plate to the said main pump housing. The electric drive motor 16 is preferably of the relatively slow, constant speed variety to minimize reduction gear requirements as described hereinbelow. An example of such motor is found in the Type SS-lSO constant speed motor of 72 r.p.m. rating manufactured by the Superior Electric Company.

A drive shaft 22 extends as shown from electric motor 16, and includes a drive gear 24 fixedly positioned thereon.

in any convenient manner so as to be rotatable therewith. A support shaft 26 extends as shown from the housing 10 and is maintained in position relative thereto by pin 11 extending therebetween. member 30 is mounted for rotation on support shaft 26 by bearings 15 and 17 positioned therebetween, and is retained on the said shaft by washer 36 and snap ring 38 positioned as shown on the adjacent extremity of the shaft. A spacer ring 13 is provided to properly space bearings 15 and 17 along the shaft 26. A gear 28 is fixedly at tached to the upper portion 33 of the drive member 30 by attachment screws 37only one of which is depicted extending therebetween. The gear 28 meshes as shown with drive gear 24 whereby rotation of the latter will result in rotation of the former and of drive member 30 to which it is attached. The drive member 30 includes a lower portion 32 and a bearing ring 34 extending therearound. The drive member 30 is mounted in the depicted off-center manner relative to the shaft 26 and will thus act as an eccentric upon the driven rotation thereof around the support shaft 26.

An end cap 40 is positioned as shown within a complementary shaped aperture provided therefor at one extremity of the main housing 10, and is fixedly secured therein by attachment screw 42 extending therebetween. The said end cap includes a stepped aperture 46 formed as shown therein, and a bearing 48 is fixedly positioned within the said aperture at the extremity thereof which projects withiri the hollow interior portion 12 of the housing It). A similar bearing 51) is fixedly positioned as shown within a horizontally aligned aperture formed in the opposite wall of the said pump housing 10. A piston actuating rod 52 is slidably positioned as shown within the said bearings 48 and 50, with one extremity thereof extending as shown within the said end cap 40, and the other extremity thereof extending as shown through housing wall 49. A follower 53 is adjustably positioned as shown on the said actuating rod by set screw 54 (FIG. 2) extending therebetween, and includes a flanged portion 56 which extends as shown into contact with the adjacent surface of the eccentrically mounted, generally circular member 30. An adjustably positionable stop member 45 is screw threadably positioned as shown within aperture 46 and includes an adjusting knob 49 extending therefrom. The said stop member, and

adjacent extremity of the actuating rod 52, cooperate, by the abutment therebetween, to limit the extent of the travel of the said rod to the right as seen in FIG. 1. This in turn functions to limit the stroke of the pump, and the delivery thereof accordingly, in the manner made clear hereinbelow. A locking screw 51 (FIG. 2) extends as shown through the wall of the main housing into contact with the said stop member and functions to fix the position thereof once it has been set through the use of adjusting knob 49. An indicator member 47 is carried by end cap 45 and cooperates with a dial 53' formed on the main housing to indicate the position of the said stop member and/ or the delivery of the pump at that position.

The pump cylinder and piston assembly is generally indicated at 60 in FIGS. 1 and 2, and is supported as shown from a cradle-like portion 62 of the main pump housing 10, and maintained therein by end plate 64 bearing thereagainst, and attachment screws 66 extending therebetween. A pump actuating assembly is generally indicated at 68 and projects as shown from the said pump cylinder and piston assembly 60 toward the adjacent, rounded extremity 70 of the piston actuating rod 52. The said actuating assembly includes a connecting rod 72 (FIG. 3, an extremity 74 of which projects into contact with the said extremity 70 of the piston actuating rod. An

A generally circular driveend plate 76 is retained as shownadjacent the said eX- ton actuating rod to maintain contact therebetwee'n at alltimes during operation of the pump. Thus may be understood whereby the compression spring 80 will at all times function to bias piston actuating rod 52 toward the eccentrically mounted driving member 30, to make clear that rotation of the latter due to driven rotation of shaft 26 will in turn result in reciprocation of the said actuating rod in the horizontal direction, as seen in FIG. l.

Referring now to FIGS. 3 and 4, the pump cylinder assembly may be seen to comprise a housing 100 which is preferably made of stainless steel or other material which is resistant to corrosion by the various liquids for which the pump may be utilized. The said housing comprises a cylindrical bore 120 for the cylindrical piston or plunger 140, threaded bores 160 and 180 for the valve housing nipples 200 and 220, respectively, which are secured in the said bores by being screw-threaded therein, and a bore 240 which provides a passager for the liquid to be pumped into the cylinder, at the opening 250 in said passage intermediate the opposite end openings of said passage, and for the subsequent passage of liquid out of the cylinder during the pumping operation. A locating pin 252 extends downwardly as shown from the housing 100 and is designed to fit in a complementary shaped notch 254 (FIG. 1) formed as shown in main housing portion 62 when the pump cylinder assembly is positioned thereon to insure proper location of the former relative to the latter.

Pursuant to the present invention, the piston 140 is made of corrosion-resistant material, as for example, tungsten carbide, and is secured to the connecting rod 72 in any satisfactory manner, as for example, by soldering an end portion of the said piston in a complementary shaped aperture 400 provided therefor in the adjacent extremity of the said connecting rod. In both hereindisclosed preferred embodiments, housing 100 includes a threaded end portion 102 projecting therefrom toward the main housing 10, and a generally cylindrical cap 104, comprising complementary shaped threaded end portion 106, is removably secured to the said housing 100 by threaded attachment of the said threaded end portion. The said generally cylindrical cap includes an aperture 112 extending therethrough as shown, and the said connecting rod 72 is slidably positioned therewithin with guide bushing 114, formed of Kel-F or a similar antifriction material to obviate the ned for lubrication, provided therein to enable the free movement of the said connecting rod relative thereto.

Member 122 is positioned as shown in complementary shaped apertures 124 and 126 provided therefor in the respective projecting end portions of housing 100 and generally cylindrical cap 104. The said member in turn includes an aperture 128 formed therein within which the said piston and connecting rod are joined together in the manner described hereinabove. A sealing ring 132 is positioned as shown within aperture 124 adjacent one extremity of the member 122 and functions to prevent liquid which may leak through bore 120 around piston 140 from proceeding therepast. A guide ring 134 is positioned as shown adjacent the extremity of connecting rod 72 within aperture 128. Thus may be understood whereby rotation of the eccentrically mounted driving member 30 will in turn result in reciprocation of piston 140 Within cylindrical bore 120. v

The valve means of the presentinvention will now be described with particular reference to FIGS. 3, 4 and 5. The inlet valve means and the outlet valve means are the same and are designated by the reference numeral 590, each of the said valve means having a close fit within its companion housing 180 and 290, respectively. The

valve means 590 comprise a valve body 560, formed of Teflon or other suitable corrosion-resistant plastic, and are provided with a plurality of ball valves 580 and 600 which are also formed of corrosion-resistant material, for example stainless steel or tungsten carbide. A plurality of valves are usually provided in pumps of the type to which the present invention relates as a precaution against the leakage of liquid when the valves are seated in their closed positions. The annular valve seats for the ball valves 580 and 600 are indicated at 629 and 640, respectively.

Pursuant to the present invention, ball valve 600 is larger than ball valve 580, and the seats for the said valves are correspondingly dimensioned so that the valve body 560 can be made in one piece and yet be provided with two valve seats. The outlet opening 664) in outlet housing nipple 220 is square so that liquid may be discharged through the outlet valve even though the ball valve 600 abuts the inner surface of nipple 220 around outlet opening 660, which might happen during the output stroke of piston 140. Similarly, passage 24!), or at least the ends thereof adjacent ball valve 600 of the inlet valve means 209, is square so that liquid may enter said passage 249 and the cylindrical bore during the intake stroke of the piston, even though the ball valve 600 of the inlet valve means 200 might abut the adjacent surface of the valve housing at the inlet end of the passage 240.

Each of the valve bodies 560 is provided with fluid seeking means 680 and 7%, of identical constnuction but different size, at its opposite ends, respectively. Referring to FIG. 4, the sealing means each comprises a flexible annular flange 720 pressed outwardly by a toroidal metal spring seal member 749 for fluid-tight sealing engagement with the inner end of the nipple 220 and the wall of housing 19%) adjacent the outlet end of passage 24%), respectively, in the case of the outlet valve means; or with the inner end of nipple 200 and the wall of housing 100 adjacent the inlet end of passage 24%, respectively, in the case of the inlet valve means. The said flanges 720 have medial circumferentially extending convex portions 750 for improving the fluid seal by being pressed into fluid-tight sealing engagement with the adjacent surfaces referred to above. It will be noted that the flange of the fluid sealing means 700 defines a circular opening 780 for the passage of fluid through the valve body when the ball valves 580 and 600 are unseated from the respective valve seats 620 and 640. The toroidal spring sealing members can be readily inserted in the valve housing through openings 780, since flanges 720 are flexible.

The embodiment of FIG. 7 is generally similar to the embodiment of FIGS. 16, with the exception that the former is particularly adapted to the accurate pumping of extremely small quantities of liquid, and to this effect utilizes a stepped piston generally indicated at and comprising portions 152 and 154 interconnected as shown by a tapered portion 156. In this embodiment, a passage 158 extends as shown into passage 240 on the opposite side of and in alignment with cylindrical bore 120. A threaded end cap 162 and a seal ring 154 are positioned as shown within the said passage 158. A bore 166 is formed in the said end cap 162, and piston portion 154 slidably extends as shown thereinto with a fluid-tight fit. Thus may be understood whereby reciprocation of piston 150, and especially tapered portion 156 thereof, across passage 240, results in a pumping action within the said passage due to the differential area between piston portions 152 and 154, respectively. As should be obvious, this differential area can be made extremely small wlhereby extremely small quantities of liquid may be accurately pumped by the reciprocation ot the said piston. The use of a stepped piston and a small differential area between the respective portions thereof eliminates the need for the use of an extremely thin, and accordingly very fragile and difiicult to manufacture, piston to thus provide greatly in creased dependability in applications wherein it is desirable to pump extremely small quantities of liquid.

The operation of the pumps, and of the inlet and outlet valve means thereof, is believed clear from the above description. Thus, with regard to the embodiment of FIGS. l6, when the piston 140 is moved through the intake stroke thereof to the right, as seen in FIG. 1, liquid is drawn into the valve body 560 of the inlet valve through nipple 200, wit-h ball valves 58-0 and 600 being unseated by the reduced pressure conditions within passage 240 and cylindrical bore 120 created by the intake stroke of the said piston. Fluid passes through the said valve body into the said passage 248 and from the latter through the opening 250 to the cylindrical bore 120, with outlet ball valves 580 and 600 remaining closed since the pressure in nipple 220 is greater than the pressure in passage 240 dur ing the intake stroke of the piston. Upon completion of the said intake stroke, the inlet ball valves close automatically under the influence of gravity, and the piston is moved in the opposite direction for the liquid output stroke, namely to the left, as seen in PEG. 1. This expels the liquid from the cylindrical bore 120 into the passage 240 and therefrom through the outlet valve body 560 and through the opening 650 of the outlet nipple 2219. The ball valves 580 and 600 at the inlet nipple 200 remain closed because the pressure in passage 240 is then higher than the pressure in the fiuid in inlet nipple 200. t may thus be readily understood that ball valves 580 and 600 act as one way valves since they are opened by the pressure of the fluid when flow of the liquid is in one direction, and are closed by liquid pressure acting in the opposite direction. The pump of the embodiment of FIG. 7 functions in the same general manner, with the main exception residing in the fact that the reduced and increased pressure conditions corresponding to the respective intake and output strokes of piston 140 of the embodiment of FIGS. 1-6, are created therein by respective movement to the right and left, through passage 240 and cylindrical bore 120, of the tapered portion 156 of stepped piston 1532. Convenient and positive adjustment of the respective strokes of the said pistons, and thus of the respective outputs of the said pumps, may be effected in each by the loosening of the locking screw 51, rotation of the adjusting knob 150 to re-position stop member 45 while concurrently observing indicator member 47 and dial 53', and the re-tightening of the said locking screw when the said indicator member and dial indicate a stop member positioning coincidental with the desired pump output.

Certain features shown but not described herein are shown in my application, Serial No. 283,928, filed May 28, 1963, now US. Patent No. 3,220,351, issued Nov. 30, 1965.

While I have shown and described the preferred embodiment of the invention, it will be understood that the t5 invention may be embodied otherwise than as herein specifically illustrated or described, and that certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may be made without departing from the underlying idea or principles of this invention within the scope of the appended claims.

What is claimed is:

1. A pump comprising a cylinder; valve means coupled to said cylinder for the intake and output of fluid to said cylinder; a piston reciprocable in said cylinder in fluid intake and output directions; spring means biasing said piston in said fluid intake direction; and piston actuating means including a rod journaled adjacent each end for reciprocation on an axis common with said piston and having one end for abutment against an end of said piston against the bias of said spring means, a projection fixed to said rod, a cam journaled for peripheral abutment against said projection for driving said end of said rod against said piston end during fluid output, and a motor coupled to said cam for rotating said cam.

2. A pump according to claim 1 further including adjustable stop means for limiting the distance traveled by the rod under the bias of said spring means.

3. A pump according to claim 1 further including adjustable stop means for limiting the distance traveled by said piston under the bias of said spring means.

4. A pump according to claim 11 further including adjustable stop means for moving said projection with respect to the periphery of said cam.

5. A purrrp according to claim 1 wherein said rod, projection and cam are disposed within a housing with said one end of said rod projecting without said housing; and wherein said cylinder piston, and spring means are dis posed without and releasably mounted to said housing.

References Cited by the Examiner UNITED STATES PATENTS 462,666 11/1891 Dykes 103-213 481,043 8/1892 Middlekauf 103-169 1,047,857 12/1912 Thomsen 103-38 1,572,045 2/1926 Scott 103-153 2,148,671 2/1939 Allen 103-38 2,599,195 6/1952 Nemetz 103-38 2,620,734 12/1952 Saalfrank 103-213 2,654,326 10/1953 Sheen 103-213 2,696,785 12/1954 Blue 103-153 2,727,466 12/1955 Kling 103-38 2,791,180 5/1957 Gorham 103-38 2,847,940 8/1958 Serres 103-153 2,861,520 11/1958 Lindsey 103-153 2,962,904 12/1960 Soccart 103-38 LAURENCE V. EFNER, Primary Examiner.

Claims (1)

1. A PUMP COMPRISING A CYLINDER; VALVE MEANS COUPLED TO SAID CYLINDER FOR THE INTAKE AND OUTPUT OF FLUID TO SAID CYLINDER; A PISTON RECIPROCABLE IN SAID CYLINDER IN FLUID INTAKE AND OUTPUT DIRECTIONS; SPRING MEANS BIASING SAID PISTON IN SAID FLUID INTAKE DIRECTION; AND PISTON ACTUATING MEANS INCLUDING A ROD JOURNALED ADJACENT EACH END FOR RECIPROCATION ON AN AXIS COMMON WITH SAID PISTON AND HAVING ONE END FOR ABUTMENT AGAINST AN END OF SAID PISTON AGAINST THE BIAS OF SAID SPRING MEANS, A PROJECTION FIXED TO SAID ROD, A CAM JOURNALED FOR PERIPHERAL ABUTMENT AGAINST

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