US3780912A

US3780912A - Metering and dispensing apparatus

Info

Publication number: US3780912A
Application number: US00027289A
Authority: US
Inventors: M Sanz
Original assignee: Micromedic Systems Inc
Current assignee: Micromedic Systems Inc
Priority date: 1968-04-02
Filing date: 1970-08-19
Publication date: 1973-12-25
Anticipated expiration: 1990-12-25

Abstract

A metering and dispensing apparatus with a pump having intake and discharge strokes coupled to a switching valve which cylindrically connects the pump in open communication with a first, then a second, port with an idling pause between the conditions. A mechanism converting rotary motion to sinusoidal reciprocating motion actuates the pump piston, the length of stroke of the piston being selectively adjustable within the motion conversion mechanism in accordance with an indicator indicative of the desired volume.

Description

United States Patent Sanz Dec. 25, 1973 154] METERING AND DISPENSING APPARATUS [56] References Cited [75] Inventor: Manuel Claude Sanz, Geneva, UNITED STATES PATENTS Switzerland 459,299 9/1891 Mills 417/434 717,084 12/1902 Denham 417/238 [73] Asslgnee 'F F systems 1,946,559 2 1934 Weiskopf 417/519 x Phlladelphla, 2,548,738 4/1951 Orlich et al.... 417/434 x Filed: g 1970 3,089,618 5/1963 Forsyth 222/63 X [2]] Appl' 27289 Primary ExaminerSamuel F. Coleman Related US. Application Data Attorney-G. W. F. Simmons and Carl G. Castellan [63] Continuation-impart of Ser. No. 812,177, April I,

1969, Pat. No 3,669,319. [57] ABSTRACT [30] Foreign Applicafion Priority Data A metering and dispensing apparatus with a pump 1 7 having intake and discharge strokes coupled to a 1968 sweleflend 4868/68 switching valve which cylindrically connects the pump Augl191968 swltz-er-laqdmvm 12426168 in open communication with a first, then a second, 7 port with an idling pause between the conditions. A [52] US. Cl. 222/282 mechanism converting rotary motion to sinusoidal [51] Int. Cl. Glf ll/06 ciprocating' motion actuates the pump piston the [58] Field of Search 417/236, 238, 239, length of Stroke of the piston being Selectively adj-lisp 417/269* 519; 2 able within the motion conversion mechanism in ac- 319 cordance with an indicator indicative of the desired volume.

20 Claims, 35 Drawing Figures /0 m 3113s 307' I 20s \-2/ 9 29 go; l 702 207 20 1 4 g a; 20 320 I06 2 333 3341 1 2 605 605 6/3 I05 7 J07 604 602 609 608 I07 33 I02 321 32 2 325 320 507 506 6/0 1 I2 104:, 19 310 22 329 1 6a a 338 340 29 34/ m I PATENTEU DEC 2 5 I975 SHEET 0 OF 18 v wt m 6k i mmm mmm mmm ow mwm v mOm mOm MG E QM MENU-10050251915 SHEET 05 0F 18 FIG.

PATENIEBUECPS I915 FIG. /4

SHEEI PATENTED EH12 5 I975 SHKET OQUF 18 FIG. /9

PATENIEU 05025 ms 3780.912

sum IOUF 18 FIG. 16

PATENIEflumzs I975 sum mar 18 mom mom \N QR B whim 1 A mm H Bm 9% JLF Tm m m :11! .i@ Om PATENIEU DEC 25 ms wOm mum QM lmmw PATENIED 0pc 2 5 ms SHEEI 1% 0F 18 Pmmmniczs ms 3780.912

sum IBM 18 PATENTEU D'EB 25 I973 SHEET 17 0F 18 PATENIEU DEC 2 5 I975 SHEEI 180F 18 1 METERING AND DISPENSING APPARATUS This application is a continuation-in-part of application Ser. No. 812,177, filed Apr. 1, 1969, now U.S. Lette a N913 9 9-W This invention relates to a metering cum dispensing apparatus of the kind for repeatedly drawing off, through a conduit, a volumetrically metered, freely adjustable, quantity of liquid and for discharging this metered quantity through another conduit, each drawing off operation alternating with a discharging operation.

Metering cum dispensing apparatuses of this kind are known: they are mainly used in test laboratories, e.g. biochemical and clinical laboratories, and are intended either to deliver a predetermined volume of a liquid to be analyzed (i.e. operating as a metering apparatus), or to deliver successively several metered quantities, all of identical volume, of the same liquid (i.e. operating as a dispensing apparatus), or else to deliver simultaneously both a volumetrically predetermined metered quantity of a liquid having to be analyzed and a metered quantity, also volumetrically predetermined but not necessarily of same volume as the liquid to be analysed, of a diluting liquid or of a reagent (i.e. operating as a diluting apparatus). The use of these apparatuses is becoming more and more widespread as the demand for chain testing increases. However, the known apparatuses are often oflow accuracy, inasmuch as the volumetric quantities they meter lack accuracy and are not readily reproducible, particularly when these volumetric quantities are small.

This defect is largely due to the fact that, in these known forms of apparatus, adjustment of the metered quantity is not fdigitalized" Indeed, adjustment is, as it were, continuous and such adjustment is often affected by errors in the reading of scales, these being human errors attributable to distraction, inattention or tiredness on the part of the operators. Moreover, the known forms of metering apparatus operate in a rather brutal way. First, an abrupt suction action occurs, then an abrupt stoppage of the suction action and finally an abrupt discharge of the metered quantity of liquid that has been sucked in. This often results in cavitation or breaks in the columns of liquid (hydraulic hammering effects) or in the formation of drops, both being a source of material errors. If it is desired to reduce the extent of these errors, this can only be achieved, with these known forms of metering cum dispensing apparatus, by having them handle relatively large quantities of liquid. This of course is a major drawback when it is required to carry out a large number of different tests on a liquid from one source since, in order to do this, a corresponding number of samples is usually required of the liquid and this means that quite a sizable starting quantity will be needed. The only way in which this need for a sizable starting quantity of the liquid can be avoided is io'r'duce to the greates t pos sibleextent the volume of each sample. Hence, the desirability of minimizing all possible causes for inaccuracy in metering. This is particularly important in haematology where it is often desired to carry out a large number of tests without having to draw off large quantities of blood from the patients. One of the most relevant examples is in pediatric haematology.

An object of the present invention is to overcome the above mentioned drawbacks by providing a metering cum dispensing apparatus which is able to meter with great accuracy very small volumes of liquid and which will lend itself, because of the reproducibility of the metered quantities it 'deliv eEToEn aiit orriizafioifof testing.

It is a further object of this invention to provide a metering and dispensing apparatus having two piston pumps with selectively variable strokes in order to meter and/or dispense any predetermined volume of liquid.

A further object of this invention is to provide a novel valve switching mechanism for a metering and dispensing apparatus.

A further object of this invention is to provide various novel improved metering and dispensing pumps.

Still another object of this invention is to provide an improved vairable stroke motion for a metering and dispensing apparatus.

According to the present invention there is provided apparatus of the kind set forth which comprises a. a unit having 1. a suction and forcing piston pump able, during a iiibn stroke, tod raw off said predetermined volume,

2. a switching valve associated with said pump and able cyclically to pass from one condition in which it causes said pump to communicate with one of said conduits, to a second condition in which it causes said pump to communicate with the other of said conduits,

3. a drive mechanism able to cause said valve to pass from one condition to the other and able cyclically to actuate said pump by imparting to the reciprocating movement of the piston a substantially sinusoidal action, said mechanism being adapted so that the suction strokes of the pump occur when the valve is in said one condition and that the forcing strokes of the pump occur when the valve is in said other condition and so that each suction and forcing stroke may be followed by an idling pause during which the valve passes from one condition to another,

4. adjustment means for selectively adjusting the volume of said metered quantity by varying the length of the stroke of the pump piston, and

5. display means for displaying to the outside a number indicative of said volume;

b. an electric motor coupled to the drive mechanism of said unit; and

c. control means for controlling said electric motor and adapted to trigger off at will half an operational cycle of said unit, said half cycle being either a drawing off half cycle, including a suction stroke of the pump, or a discharge half cycle, including a forcing stroke of the pump.

Three embodiments of the apparatus provided by the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a side view, in cross-section of a first embodiment of this invention;

FIG. 2 is a front sectional view of the first embodiment, taken along line Il--II of FIG. 1;

FIG. 3 is a rear sectional view of the first embodiment, taken along line IIIIlI of FIG. 1;

FIG. 4 is a plan view of the first embodiment;

FIG. 5 is a front elevational view of the first embodiment;

FIGS. 6 and 7 are detail sectional views taken along lines Vl-VI and VII-VII, respectively, of FIG. I, on a somewhat enlarged scale;

FIG. 8 illustrates a further detail, partly in section, of

Claims

1. A measuring and dispensing apparatus comprising a base, motor means, a first motion-translating means adapted to translate rotary motion into sinusoidal reciprocal motion, a second motiontranslating means adapted to translate rotary motion into substantially reciprocal movement, power-translating means connecting said motor means and said first and second motiontranslating means to operate them, a pump having a cylinder and a piston reciprocable in the cylinder, valve means having a passage communicating with the interior chamber of the cylinder and two ports and adapted to alternately connect each of said ports with said passage, a support member on said base, means for connecting said pump to said member, said second motion-translating means being operatively associated with said valve means and operating it to alternately connect each of the ports with the chamber through said passage at set times, and a reciprocating arm connected to said first motion-translating means and said piston to provide strokes of sinusoidal amplitude thereto.

2. An apparatus as in claim 1 wherein the cylinder and valve means are mounted within an elongated tubular housing, the valve means being adjacent an end wall of the cylinder and comprising a rotary member having a passageway adapted, on reciprocation of the rotary member about its axis, to alternately place each port in open communication with the chamber through the aforesaid passage, at least one driving stud secured to the rotary member and projecting beyond said end of the housing, the valve-switching means comprising a reciprocable valve-driving means, and lever means engaging the stud or studs and arranged to be reciprocated by the reciprocable valve-driving means for reciprocating the rotary member about its axis.

3. An apparatus as in claim 2 wherein the pump-connecting means comprises a second stationary supporting member having a bore and a groove therein, a shaft having a spherical bearing on which the housing and the valve means are supported for relative motion, said shaft extending into said bore, means for locking said shaft in said bore, a sleeve surrounding a portion of said shaft and supporting said lever means pivotally thereon, and pin means rigidly attached to the housing and projecting axially therefrom, the pin means having an axis at right angles to the plane of reciprocation of the arm and engaging the slot and being rotatable therein to permit swinging of the housing on the axis of the pin mEans while preventing rotation of the housing about the axis of the rotary member during reciprocation of the lever means to actuate the valve.

4. The apparatus as in claim 2 wherein said lever means has at least one slot therein engaging said driving stud, and a projection on the end of said lever engaging said second motion translating means.

5. The apparatus of claim 4 wherein said lever has a figure eight shaped slot, said shaft engaging said lever through said slot whereby said lever can be moved longitudinally to disengage said lever projection from the second motion translating means to leave the cylinder chamber means in communication with only one port bore or neither.

6. An apparatus as in claim 1 wherein said pump includes a priming means, said priming means adapted to place a source of suction in open communication with said cylinder means.

7. An apparatus as in claim 6 wherein said priming means comprises a manually operable rotatable threaded valve member, a threaded aperture in said housing, a first passage means in said valve member, a second passage connecting said valve member with said cylinder, said valve member having a gate means adapted to place said first and second passage means in open communication upon rotation of said valve means.

8. An apparatus as in claim 2 wherein said power transmitting means includes at least one driven gear, a cam mounted on said gear, a plate means mounted for vertical sliding movement on said base means, an aperture means in said plate means, said aperture means surrounding said cam means and adapted to vertically reciprocate on said cam means, said aperture means being so configurated that said plate means pauses between its upward and downward movements, at least one pivot plate member mounted for pivotal movement on said plate, a second smaller aperture means located on said pivot plate member, a stud on said cam projecting through said second aperture means and adapted to limit the amount of pivotal movement of said pivot plate member, a slot in said pivot member, said lever means having a projection engaged in said slot whereby the rotation of said gear rotates said cam, thereby causing said plate means to intermittently vertically reciprocate which, in turn, causes the pivot plate member means to reciprocally pivot within the limit prescribed by said stud upon upward and downward movement of said plate, and the movement of said pivot plate member actuating said lever means.

9. An apparatus as in claim 8 wherein the first aperture means comprises the shape formed by two overlapping rectangles.

10. An apparatus as in claim 8 wherein said first motion translating means has a second gear driven by the first-mentioned gear, said first and second gears engaged to drive said first motion translating means, said first gear having two arcuate relieved portions on its circumference whereby said second gear is intermittently driven upon rotation of said first gear, the times when said second gear is not driven corresponding to the up and down movements of said plate means to allow said valve switching mechanism to change ports on said pump.

11. An apparatus as in claim 10 wherein said first gear has two upstanding studs adjacent said relieved portions and said second gear has two spokes projecting from a hub portion thereof, said studs engaging said spokes respectively to start said second gear rotating before the gears remesh.

12. An apparatus as in claim 8 wherein said first motion translating means includes means to linearly adjust the length of stroke of said reciprocating arm.

13. An apparatus as in claim 8 wherein said cam, plate means and pivot plate member are located between the first-mentioned support member and another support member upstanding portions said base.

14. An apparatus as in claim 1 wherein said power transmitting means includes a reduction gear box, said reduction box is connected to said motor, at least one idler gear is driven by saiD reduction gear box, and a gear for driving said first motion-translating means is in engagement with said idler gear.

15. An apparatus as in claim 14 wherein said base has microswitches mounted thereon adjacent said idler gear, and there is means on said idler gear adapted to activate said microswitches to control the operation of the apparatus.

16. An apparatus as in claim 14 wherein said idler gear has means thereon to activate said second motion translating means.

17. An apparatus as in claim 16 wherein said activation means comprises a cam.

18. A system for metering and dispensing liquids comprising at least two pumps, each pump having a piston and cylinder and at least two ports thereon, power means to drive said pistons, a reservoir means, adjustment means adapted to adjust the stroke on each piston, manually adjustable valve means on each pump adapted to connect said pump cylinders with either both ports alternately or only one port, a common dispensing and aspirating nozzle in communication with one port on each pump, said reservoir being in communication with at least one of the other ports of the two pumps, each pump including interchangeable members, thereby allowing the capacity of the pumps to be varied, whereby said arrangement allows for many dilution and sampling procedures to be carried out on said system.

19. A system as in claim 18 wherein said power means driving said pistons may be adjusted so that the pistons move in parallel or alternating strokes.

20. A system as in claim 18 wherein said power means includes cam means adapted to only operate said valve means when said pistons are at the top or bottom of their strokes.