US3288079A

US3288079A - Pump

Info

Publication number: US3288079A
Application number: US398860A
Authority: US
Inventors: Nelson G Kling
Original assignee: Technicon Chromatography Corp
Current assignee: Technicon Chromatography Corp
Priority date: 1964-09-24
Filing date: 1964-09-24
Publication date: 1966-11-29
Anticipated expiration: 1983-11-29

Description

N. G. KLING UMP 3 Sheets-Sheet 1 Filed Sept. 24, 1964 FIG.

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w M w 6 /7 0 Hy v INVENTOR NELSfl/V 5. KL/NG ATTORNEY United States Patent PUMP Neison G. Kling, Ringwood, N.J., assignor to Technicon Chromatography Corporation, Chauncey, N.Y., a corporation of New York Filed Sept. 24, 1964, Ser. No. 398,860 8 Claims. (Cl. 103153) This invention relates to fluid pumps, and particularly to positive displacement, small volume, pumps.

In the US. patent application of Nelson G. Kling, S.N. 361,726, filed April 22, 1964, there is disclosed a variable delivery, reciprocating pump of conveniently adjustable stroke which utilizes a relatively slow, constant speed drive motor to minimize reduction gearing requirements, while insuring constant volume delivery at each stroke adjustment.

It is an object of this invention to provide a pump of the type disclosed in the aforementioned application which is particularly adapted to the pumping of small volumes.

It is another object of this invention to provide a rugged pump having a small chamber volume.

It is yet another object of this invention to provide a pump which is particularly suited for the delivery of liquid to a chromatographic column at a constant volumetric rate.

A feature of this invention is the provision of a pump head having a chamber formed of a non-wetting plastic which is reinforced by a surrounding metal tubular structure.

Another feature of this invention is the provision of a pump head for a reciprocating piston pump having a chamber which is occupied by incompressible movable elements which do not interfere with the proper operation of the valve elements and the passageways.

These and other objects, features and advantages of this invention will become more clearly apparent from the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a front elevation, partly in section, of a pump embodying this invention;

FIGURE 2 is a side elevation of the pump of FIG- URE 1; and

FIGURE 3 is a detail elevation of the pump head taken along the line 33 of FIGURE 2.

The pump comprises a housing assembly 10, a pump head assembly 12, and an electric motor 14. The motor 14 is fixed to a thermal insulating annular plate 16, advantageously made of a phenolic plastic, by a plurality of machine screws 18. The plate 16 is mounted over an opening 20 in the top of the pump base 22 by a plurality of machine screws, not shown. The motor has a shaft 24 which extends downwardly through the opening 20 into the hollow inner portion 26 of the base 22. The motor is preferably of a relatively slow, constant speed type to minimize the reduction gear requirements.

A support shaft 28 is fixed Within the base through a bore 30 therein by a cross-pin 32. A sleeve bearing 34 is mounted on the shaft and a cylindrical element 36 or cam is eccentrically mounted on the sleeve hearing. The bearing and the cylindrical element are retained on the shaft by a washer supported by a snap ring 38 fixed within a groove in the lower end of the shaft.

A relatively large spur gear 40 is fixed to the cylindrical element 36 by a machine screw 42 and is concentric with the support shaft 28. A relatively small spur gear 44 is fixed to the motor shaft 24, and meshes with the gear 40. The inner race 46 of a ball bearing assembly 48 is fixed to and is concentric with the cylindrical element 36.

The base has two

concentric bores

50 and 52 through the left and

right ends

54 and 56, respectively. A sleeve 3,288,079 Patented Nov. 29, 1956 bearing 58 is friction fitted into the bore 50. A cylindrical end cap 60 is fitted through the bore 52 and fixed by a machine screw 62 through its enlarged end portion 64 into the base. The end cap has a bore 66 therein of relatively small diameter into the left end portion of which is fixed a sleeve bearing 68. The right end portion is enlarged and threaded to receive a threaded stop rod 70 having a manually graspable knob 72. The rod 70 has an indicator 74 fixed thereto which cooperates with a tubular scale 76 to indicate the longitudinal position of the rod.

A rod 78 is mounted for reciprocation within the

sleeve bearings

58 and 60. A flanged follower 80 is fixed to the shaft 78 by a cross pin 82 and has a flat circular face 84 which will abut the outer race 86 of the ball bearing assembly 48. A plate 88 is fixed to the underside of the base by a plurality of machine screws 90 to close the hollow portion 26.

The pump head assembly 12 is fixed to a circular flat exterior face 92 on the end 54 of the base by three rods 94. Each rod has a central hexagonal-sectioned portion 96, a threaded end portion 98, and a circular end portion having a threaded axial bore 102 therein. The threaded end portions are fixed within corresponding threaded bores 104 in the base. A circular platev 106 having a peripheral shoulder 108, an axial stepped hole 110, three holes 112 and three holes 114, is mounted on the three rods 94 which respectively pass through the holes 114. A tube 116 is supported between the face 92 and the plate 106 by the shoulder 108. A block 118 of plastic having self-lubricating, non-wetting characteristics, such as a fluorinated hydrocarbon, is fixed to the plate 106 by three machine screws 120 which respectively pass through the holes 112 and respectively engage three threaded inserts 122 moulded into the block 118. A plate 124 having three holes 126 is mounted to the ends of the rods 94 by three machine screws 128 respectively pass.

ing through the holes 126 and into the threaded bores 102.

A tubular metal insert 130 is moulded into the block 118. The insert has a transverse diametric hole 132 therethrough which serves to key the insert fixedly within the block. The uppermost portion of the insert is internally threaded to receive a tube fitting assembly 134. The remainder portion of the insert includes a core of the plastic. This core has a central coaxial bore or chamber having an upper portion 136 of relatively large diameter and a curved seat to accommodate a ball 138, a middle portion 140 of lesser diameter and a curved seat to accommodate a ball 142, and a lower portion 144. A radial bore 146 passes through the block to intersect the lower bore portion 144. The radial bore 146 includes En gnlarged portion into which a nipple 148 is presstte Disposed within the tube 116 is cylindrical element 150 having a flanged end portion 151 which is captured between the block 118 and the inwardly extending fiange of stepped hole 110. The cylindrical element 150 has an axial bore therethrough which is coaxial with a bore 152 through the block 118 intersecting the bore middle portion 140. This axial bore has a portion 154 into which a sleeve bearing 156 is fitted; a portion 158 of larger diameter, and a portion 160 of yet larger diameter. The bore 152 includes a portion 162 of enlarged diameter into which a plurality of shaft seals 164 are fitted. An annular seal plug 166 is fitted in part in the bore portion 162 and in part in the bore portion 160. A rod having a portion 168 of larger diameter is disposed through the sleeve bearing 156 and a portion of smaller diameter 170 is disposed within the bore 152. A flanged annular plate 172 is disposed on the rod portion 168 adjacent a snap ring 174 fitted into a groove in the rod.

A snap ring 176 is also fitted into a groove in the rod and is adapted to abut a Washer 178 disposed in the bore portion 158. A helical compression spring 180 is disposed about the cylindrical element 150 between the plate 106 and the plate 172. The spring biases the end of the rod portion 168, by means of the plate 172 and the snap ring 174, against the end of the rod 78. The snap ring 176 precludes the loss of the rod portion 168 from the cylindrical element 150. A plurality of holes 182 communicate with the atmosphere, or at least the volume of air enclosed by the tube 116 to preclude any pumping action within the bore portion 158 by the shoulder between rod portions 168 and 170. Snap ring 176 is provided with one or more holes (not shown) to prevent pumping action in bore 158.

It will be seen that when the motor 14 rotates by means of the gears 44 and 40 it rotates the cylindrical element or cam 36, which engages the follower 80 by means of the ball bearing assembly 48 to reciprocate the rod 78 against the bias of the compression spring 180. The leftmost travel of the rod 78 is determined by the rise of the cam 36, while the rightmost travel of the rod 78, after the cam has dropped away from the follower 80, is determined by the position of the rod 70.

Disposed within the bore portion 140 of the pump chamber above the ball 144 is a cylindrical insert 184 which is smaller in diameter than the bore portion 140, and smaller in length than the spacing between the

balls

142 and 138 when they are both seated. Disposed within the bore of the metal insert above the ball 138 and below the fitting assembly 134 is a mushroom shaped cylindrical insert 186. The insert 186 has a domed, solid head portion 188, and a tail portion 190 having an axial hole 192 which is intersected with a diametn'c hole The nipple 148 is coupled by a tubing 196 to a source of liquid. The tubing assembly 134, consisting of a plug 198, having a bore 200 with an enlarged portion 202 having a diameter greater than the diameter of the insert portion 194, a cap 294, a conical wedge 206, and tubing 208 is coupled to a receiver of liquid. The plastic block may be made of Teflon. The rod portion 170, the

balls

142 and 138, the inserts 184 and 186, and the tubular insert 130 may advantageously be made of stainless steel.

As the rod portion 170 is reciprocated to the sight it enlarges the volume of the pump chamber, reducing the pressure therein. The lower ball rises from its seat admitting liquid from the source which is at atmospheric pressure. Liquid is admitted to fill the volume below the upper ball 138. This volume is relatively small, being largely occupied by the insert 184. As the rod is reciprocated to the left reducing the volume of the pump chamber and increasing the pressure therein above atmospheric, the lower ball is seated due to the increased fluid pressure thereon and the Weight of the insert 184. The upper ball 138 is raised off its seat together with the upper insert 186, and liquid is expelled from the bore portion 140 past the ball 138 and the insert 186 into the bore of the fitting 134. Should the top of the upper fitting 186 enter entirely into the enlarged portion 202 of the bore 280 and tend to obstruct the bore 200, liquid will nonetheless be free to pass around the head portion 188, into the diametric bore 194, through the axial hole 192 and out into the fitting bore 200.

As the rod portion 170 is again reciprocated to the right, increasing the volume of the pump chamber, and reducing the ambient pressure below the upper ball 138, the ball under the increased pressure in the system coupled to the fitting 134 and the weight of the upper insert 186, is seated, while the lower ball is again raised.

While I have shown and described the presently preferred embodiment of my invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described and surrounding an elongated core of said first material which is not to be limited to the herein-described specific con-. struction, except as may be required by the scope of the appended claims considered with reference to the prior art.

What I claim is:

1. A fluid pump comprising: a body made of a first material; an elongated, tubular insert of a second material, having end and lateral openings, molded in said body surrounding an elongated core of said first material which is integral with the external portion of said body through one of said ends and said lateral opening in said insert; an elongated pumping chamber in said core; a pumping cylinder projecting transversely through said block, through said first material in said lateral opening of said insert, and through said core into fluid flow co -mrnunication With said chamber; and a piston disposed within said cylinder and operable for reciprocating movement in said cylinder.

2. A fluid pump comprising: a body made of a first material; an elongatedtubular insert of a second material having end and lateral openings, molded in said body is integral with the external portion of said body through one of said ends and said lateral opening in said insert; an elongated pumping chamber in said core; a pumping cylinder projecting transversely through said block, through said first material in said lateral opening of said insert, and through said core into fluid flow communication with said chamber; a piston disposed within said cylinder and operable for reciprocating movement in said cylinder; and a tubular coupling member :for an outlet conduit threadably mounted within and to the other of said ends of said insert, said chamber being in fluid flow communication with said coupling member.

3. A fluid pump comprising: a body made of a first material; an elongated tubular insert of a second material having end and lateral openings, molded in said body surrounding an elongated core of said first material which is integral with the external portion of said body through one of said ends and said lateral opening in said insert; an elongated pumping chamber in said core; a pumping cylinder projecting transversely through said block, through said first material in said lateral opening of said insert, and through said core into fluid flow communication with said chamber; a piston disposed within said cylinder and operable for reciprocating movement in said cylinder; a tubular coupling member for an outlet conduit threadably mounted within and to the other of said ends of said insert, said chamber being in fluid flow communication with said coupling member; and an inlet conduit disposed through said body and said one end of said tubular insert in fluid flow communication with said chamber.

4. A fluid pump comprising: a body made of a first material; an elongated tubular insert of a second material having end and lateral openings, molded in said body surrounding an elongated core of said first material which is integral with the external portion of said body through one of said ends and said lateral opening in said insert; an elongated pumping chamber in said core; a pumping cylinder projecting transversely through said block, through said first vmaterial in said lateral opening of said insert, and through said core into fluid flow communication with said chamber; a piston disposed within said cylinder and operable for reciprocating movement in said cylinder; a tubular coupling member for an outlet conduit threada'bly mounted within and to the other of said ends of said insert, said chamber being in fluid flow communication with said coupling member; an inlet conduit disposed through said body and said one end of said tubular insert in fluid flow communication with said chamber, an inlet valve ball disposed in said chamber,

and an inlet valve seat formed in said chamber adjacent said inlet conduit for receiving said inlet ball for precluding the flow of fluid between said inlet conduit and said chamber; an outlet valve ball disposed in said chamber and an outlet valve seat formed in said chamber adjacent said coupling member for receiving said outlet ball for precluding the flow of fluid between said coupling member and said chamber; and a member disposed within said tubular insert between said outlet ball and said coupling member and movable therebetween.

5. A fluid pump comprising: a body made of a first material; an elongated tubular insert of a second material, having end and lateral openings, molded in said body surrounding an elongated .eore of said first material which is integral with the external portion of said body through one of said ends and said lateral openings in said insert; an elongated pumping chamber in said core; a pumping cylinder projecting transversely through said block, through said first material in said lateral opening of said insert, and through said core into fluid flow communication with said chamber; a piston disposed within said cylinder and operable for reciprocating movement in said cylinder; a tubular coupling member fior an outlet conduit threadably mounted within and to the other of said ends of said insert, said chamber being in fluid flow communication with said coupling member; an inlet conduit disposed through said body and said one end of said tubular insert in fluid flow communication with said chamber; an inlet valve ball disposed in said chamber, and an inlet valve seat formed in said chamber adjacent said inlet conduit for receiving said inlet ball for precluding the flow of fluid between said inlet conduit and said chamber; an outlet valve ball disposed in said chamber and an outlet valve seat formed in said chamber adjacent said coupling member for receiving said outlet ball for precluding the flow of fluid between said coupling member and said chamber; a first member disposed Within said tubular insert between said outlet ball and said coupling memher and movable therebetween; and a second member disposed within said chamber between said inlet ball and said outlet ball and movable therebetween and also adjacent said cylinder.

6. A fluid pump comprising: a body made of a first material; an elongated tubular insert of a second material, having end and lateral openings, molded in said body surrounding an elongated core of said first material which is integral With the external portion of said body through one of said ends .and said lateral opening in said insert; an elongated pumping chamber in said core; -a pumping cylinder projecting transversely through .said block, through said first material in said lateral opening of said insert, and through said core into fluid flow communication with said chamber; a piston disposed within said cylinder and operable for reciprocating move ment in said cylinder; a tubular coupling member for an outlet conduit threadably mounted within and to the other of said ends of said insert, said chamber being in fluid flow communication with said coupling member; an inlet conduit disposed through said body and said one end of said tubular insert in fluid flow communication with said chamber; an inlet valve ball disposed in said chamber, and an inlet valve seat formed in said chamber adjacent said inlet conduit for receiving said inlet ball for precluding the flow of fluid between said inlet conduit and said chamber; an outlet valve ball disposed in said chamber, and an outlet valve seat formed in said chamber adjacent said coupling member for receiving said outlet ball for precluding the flow of fluid between said coupling member and said chamber; a first member disposed within said tubular insert between said outlet ball and said coupling member and movable therebetween; a second member disposed Within said chamber between said inlet ball and said outlet ball and movable therebetween and also adjacent said cylinder; and a passageway formed through said first member including a first portion adjacent to and coaxial with said coupling member and a second portion remote from said coupling member and at an angle to said first portion.

7. A pump according to claim 1 wherein said first material has a self-lubricating characteristic and said second material has a high rigidity characteristic.

8. A pump according to claim .1 wherein said first material has a non-wetting characteristic and said second material has a high rigidity characteristic.

References Cited by the Examiner UNITED STATES PATENTS 1,165,339 12/1915 Moench 92--169 2,791,969 5/ L957 'Berliner 103153 2,888,879 6/ 1959 Gaarder i103-1 14 3,125,004 3/1964 White 1031 14 FOREIGN PATENTS 567,371 2/1924 France.

701,758 .1/ 1931 France.

835,440 9/ 1938 France.

MARK NEWMAN, Primary Examiner.

HENRY F. RADUAZO, Examiner.