US 2595493 A
Description (OCR text may contain errors)
y 5, 1952 o. F. SLABY ETAL LIQUID EXTRACTING APPARATUS Filed Sept. 9, 1949 IN VEN TOR.
Patented May 6, 1952 UNITED STATES PATENT OFFICE LIQUID EXTRACTING APPARATUS Ollie F. Slaby, Parma, and Le Roy K. Mills, Lyndhurst, Ohio Application September 9, 1949, Serial No. 114,892
1 Claim. 1
Our present invention comprises novel appa ratus for extracting minutely measured quantities of fluid. and especially designed for extracting exactly measured minute quantities of blood for use in physiological researches such as the counting of corpuscles and the like.
For the purpose of blood counts it is necessary to puncture the patient and secure a very minute and precisely measured quantity of blood such as may be contained in a capillary tube; and it is further necessary to secure this relatively small exact amount of blood rapidly so as to avoid coagulation and without delay dilute such small quantity of blood with a suitable diluting fluid and this process must be accomplished very rapidly in order to obtain accurate results. In general the process involves the puncturing of the patient to obtain 'a drop of blood and the drawing of a quantity of the blood into a capillary tube exactly to a hair line graduation thereon to give a predetermined exact measure of a very minute quantity of blood and since the further procedure of the blood count is based on the assumption of an exact and very minute quantity of blood, it is apparent that the blood must not be drawn into the capillary tube even a hairs breadth off from the measuring graduation of the capillary tube.
The process of drawing the blood into the capillary tube and the subsequent dilution of the blood by drawing a diluting fluid into the capillary tube, also in an exact minute quantity, must necessarily be accomplished very rapidly in order to avoid coagulation of the blood. Hence, if the exact amounts of fluid are not drawn into the capillary tube initially, the entire operation must be repeated including the puncturing of the patient to secure a fresh drop of blood, and the instruments employed are required to be cleaned, sterilized, dried and made ready for the repetition of the operation which causes delay and annoyance both to the patient and to the practitioner.
l-Ieretofore it has been usual practice to draw the blood and diluting fluid into the capillary tube, for the purpose as above mentioned, by the use of a rubber hose attached to the capillary tube,'one end of the rubber hose being placed in the mouth of the practitioner and the blood and diluting fluid being drawn into the capillary tube by mouth sucking action. By such a process it is very difficult to procure an exactly measured amount of fluid of minute quantity as required and it takes a great deal of skill upon the part of the practitioner to procure a sum- 2 ciently close approximation of the exact quantity of fluid desired. For the practitioner who is required to perform this operation only occasionally, it is especially difficult.
It has been heretofore proposed to employ mechanical pumping devices of the piston and cylinder types with micrometer screw adjustment for the purposes of performing such operation, but such devices have not been successful despite their extremely high cost and precision manufacture because of the fact that with a piston and cylinder type pumping device a very small movement of the piston causes too great a movement of blood into the capillary tube and the piston and cylinder cannot be manufactured small enough proportionally to the size of the capillary tube to enable the minute movement of fluid in the capillary tube as required.
Moreover, in the manufacture of such piston and cylinder pump devices the parts thereof are required to be machined and lapped to very close tolerances at very great expense in order to provide satisfactory pumping action, and even though this type of pumping device is made with the greatest precision possible, it will not work without the necessity-for priming each time it is used. The necessity for priming of this type of pumping device renders it entirely impractical for use for the purposes hereof because of the time loss involved and the impracticability of having conveniently available priming means and priming fluid. However, the principal objection to piston and cylinder type pump device is that it cannot be made to draw the exact amounts of fluid required in the minute quantities necessary for the purposes described.
It is therefore a primary object of the present invention to provide apparatus for the purpose mentioned which will enable exactly measured minute quantities of fluid to be drawn into a capillary tube with highly and satisfactorily accurate control for the purpose mentioned and which apparatus may be readily manipulated with such control by relatively unskilled persons.
A further object of our invention is to provide apparatus for the purpose mentioned, having the desired characteristics of capability of accurate control, which apparatus may be manufactured at relatively small expense as compared with other less satisfactory devices and which apparatus does not require any machining operation to be performed thereon and does not require any priming in its use.
In carrying our invention into practice, We utilize a flexible, substantially air-tight fluid container, composed preferably of rubber or rubberlike material, and we dispose this flexible container within a rigid housing and connect a graduated capillary tube into fluid communication with said flexible container; and we further provide screw actuated plunger means engageable with the flexible container within its rigid housing for depressing or compressing the said flexible container to express fluid therefrom. We preferably utilize a flexible container having a bulbous or spheroidal shape and we specially form the surface of the plunger which contacts with the flexible container with a convex curvature for non-wrinkling engagement with the flexible fluid container.
For a detailed description of our invention, reference is made to the accompanying drawing in which:
Figure 1 is a view showing the complete appa ratus of our invention with the flexible fluid container, its housing, and the plunger head shown in section, and illustrating the flexible fluid container in non-compressed or fully expanded condition.
Figure 2 is a view similar to Figure l but showing the screw actuated plunger as when moved relative to the housing for action upon the flexibl fluid container to compress it to decrease the internal fluid capacity thereof.
In the drawings, the fluid extracting apparatus of our invention is designated as a whole by the letter A and comprises a substantially spheroidal housing, generally designatedby the numeral I, and consisting of two substantially hemispheroidal sections 2 and 3 which are fastened together by suitable fastenings such as the screws 4.
Within the housing I is disposed a flexible and resilient substantially air-tight fluid container which, as shown, is of bulbous or spheroidal shape and designated by the numeral 5. The flexible fluid container 5 preferably comprises a vacuum bulb composed of rubber or rubber like material such as soft rubber and the walls of which are of substantial thickness, as shown, so that the fluid container 5 is highly flexible and resilient and which normally retains its spheroidal shape, when undepressed, and after being depressed, when the depressing pressure is released, the fluid container 5 rapidly resumes its normal spheroidal shape.
The fluid container or vacuum bulb 5 is provided with a nipple 6 which extends through an opening in the lower section 3 of the housing to the outside thereof and provides a passage I for fluid communication between the interior of the container 5 and the exterior of the housing I. One end of the capillary pipette or graduated capillary tube 8 is received within the nipple 6 as shown. The capillary pipette 8 is of usual construction and comprises two capillary tubes 9 and I communicating with an intermediate mixing chamber II, the capillary tube 6 being provided with graduations 8a and the capillary tube In being provided with graduations Illa. The bulbous mixing chamber I I contains the usual mixing bead I2 which serves to prevent the blood corpuscles from aggregating when blood is drawn into the capillary pipette 8.
At the upper end of the section 2 of the housing I there is provided a threaded bushing I3 which receives and cooperates with the threads of a fine thread screw actuator I4 to the outer end of which is fixed a knurled head I for manipulation of the screw actuator I4 to rotate the same relatively to the threaded bushing I3 fixed to the section 2 of the housing. Swiveled to the inner end of the screw I4 within the housing I is an actuator head or plunger head provided with a convex bulb engaging surface I6a engageable with the vacuum bulb or flexible container 5 for depressing or compressing the same and the screw I4 is suitably actuated.
For the purpose of swivelly connecting the plunger head I6 to the screw I4, the head I6 is counter-bored axially of the screw I4 to receive a washer I'I within the larger diametered portion of the bore, which washer I1 is larger than the smaller diametered portion of the bore so as to act as a retainer for the screw I4, the inner end of which is undercut to receive the washer I1 and the end of the screw I4 is then peened over the washer to retain it on the screw. The larger diameter portion of the bore is then plugged up with a screw plug I8, the outer end of which is convex and made flush with the convex bulb engaging surface I'Ba of the plunger head l6.
In the use of the apparatus of our invention, the lower pointed end I9 is inserted in a drop of a patients blood while the vacuum bulb or flexible fluid container 5 is in depressed or compressed condition as shown in Figure 2 and then the knurled knob I5 is manipulated to rotate the screw I4 and move the actuator head I6 upwardly relative to the housing I to relieve the pressure on the vacuum bulb or fluid container 5 permitting atmospheric air pressure to force some of the blood into the capillary tube 9.
It will be seen that the preliminary actuation of the screw I4 to depress the vacuum bulb or fluid container 5 decreases the internal fluid capacity thereof driving air therefrom and when the screw I4 is actuated in opposite direction to withdraw the plunger I6 and relieve the pressure on the bulb 5, the internal fluid capacity thereof is expanded allowing more air to enter same thereby permitting the trapped air to expand into the bulb 5 and permit atmospheric air pressure to force blood up into the capillary tube 9.
It has been found that with the use of a screw I4 having a relatively fine thread of standard pitch, the movement of the plunger head in its engagement with the vacuum bulb 5 may be controlled with suflicient accuracy to allow only slight relief of bulb depressing pressure when the screw I4 is backed up such that the movement of fluid up the capillary tube 9 is relatively slow and can be stopped at the exact point desired in said capillary tube or passage 9.
Now, in the use of the apparatus for its intended purpose, the patients blood will be drawn up into the capillary tube 9 to the lower graduation 8a and it must be exactly stopped at that graduation mark as otherwise the blood count subsequently made will be inaccurate. When the blood is drawn up to the lower graduation mark 8a, the lower end I 9 of the capillary pipette is inserted into a diluting fluid and the screw I4 again actuated to relieve pressure on the bulb 5 to allow the fluid to rise in the pipette to the graduation mark Ifla and again the fluid must be stopped exactly at that graduation mark Ifla as otherwise the blood count subsequently made will be inaccurate.
The convex curvature of the bulb engaging surface I6a of the plunger head I6 is such as to cause smooth engagement of the plunger head with the vacuum bulb 5 in compressed condition, such as shown by Figure 2, whereby to prevent wrinkling of the flexible wall of the vacuum bulb 5 so 5 engaged. If the vacuum bulb 5 were wrinkled by engagement with the plunger head IE it would cause spurting or uneven flow of the fluid up the capillary tube which would result in inaccurate control of such flow.
From the foregoing it will be seen that our invention provides a very simple apparatus for the purpose which affords highly accurate control of the flow of fluid in minute quantities, which apparatus overcomes the disadvantages of devices previously proposed for this purpose, and our apparatus being capable of manufacture at relatively small cost compared with less satisfactory devices previously in use.
Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:
Fluid extracting apparatus of the class described, comprising, in combination, a flexible resilient fluid container of normally generally spheroidal shape and composed of rubber or like material, a rigid housing for said fluid container, said housing being of generally spheroidal shape corresponding to and confining said container therewithin, said fluid container having a nipple extending through said housing, a graduated capillary tube associated with said nipple for fluid communication between said capillary tube and the interior of said fluid container, and a screw actuated plunger comprising a screw actuator having threaded cooperation with said housing for axial movement relative thereto upon relative rotation of said actuator, and a plunger head swivelly connected to said actuator and disposed within said housing, said plunger head having a convex engaging surface for engagement with said fluid container to compress the same to decrease the fluid capacity thereof while closely confined within said housing, said fluid container being resilient to resume its normally spheroidal shape to increase the fluid capacity thereof upon movement of said plunger to relieve the compressing pressure on said fluid container.
OLLIE F. SLABY.
LE ROY K. MILLS.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PAI E N I S Number Name Date 805,743 McConnell Nov. 28, 1905 1,447,790 Kovacs Mar. 6, 1923 1,963,886 Chilson June 19, 1934 2,153,105 Szecsi Apr. 4, 1939 2,166,842 Kagan Jul. 18, 1939 FOREIGN PATENTS Number Country Date 341,511 Great Britain Jan. 14, 1931