US1974075A - Testing apparatus - Google Patents

Description

Sept. 18, 1934. s. LEIBOFF TESTING APPARATUS Original Filed July 20, 1929 INVENTOR'.

5; ATTORNEY Patented Sept. 18, 1934 :PATENT; OF- F ICE .TESTING APPARATUS Samuel Leo Leiboff, Bronx, N. Y.

Application July'20, 1929, SerialNo. 379,708

;Renewed- November 3, 1933 3 Claims.

The invention relates to testing apparatus, such as apparatus for the determination of urea in the blood, and the like purposes.

An object of this invention is to provide ap- 5 paratus of the character described adapted for the usual routine work whereby the amount of urea in blood may be accurately determined without complicated apparatus such as autoclaves or distillation apparatus such as is usually necessary for carrying out such determinations by the high pressure method and other methods now in use.

Another object of this invention is to provide in an apparatus of the character described, an improved, simple, cheap and highly efiicient and practical device for containing substances raised to high pressures by heat, and which device is automatically sealed upon heating the substances there within without necessitating additional 5120 clamping means.

A further object of this invention is to provide improved means for simultaneously carrying out a number of tests requiring the heating of liquids under pressure.

A still further object of the invention is to pro-- -vide-a neat, rugged and compact apparatus of the character described which shall be comparaytively cheap to manufacture, comprise fewand simple parts, be easy to manipulate and practi-.

cal and efficient to a high degree.

Other objects of this invention will in part be obvious and in part hereinafter pointed out.

The invention accordingly consists in the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter described, and of which the scope of application will be indicated in the following claims.

In the accompanying drawing in which is. shown one of the various possible illustrative embodiments of this invention,

Fig. 1 is aside, elevational view partially in cross-section of an apparatus embodying the invention, with parts broken away to show the interior construction; and

Fig. 2 is a cross-sectional view taken on line 2- -2 of Fig. 1.

Referring now in detailto the drawing, 10 designates an apparatus embodying the invention ...50 particularly adapted for use in the determination of urea nitrogen in the blood. There are now in use several methods for determining the urea nitrogen content in the blood, such as the so-called low pressure method employing urease, in which .-.55 the ammonia is either distilled or aerated into an -.method employing autoclaves.

1 of metal, such as copper. within said. beaker. 21 is a rack 22 having a base tached to said tube 25 is a disc 28 made of copper turned.

acid medium; and the so-called high pressure I Both of these methods, .as carried out heretofore, have been found to be cumbersome and quite time consuming. Furthermore, the lowpressure method hasten been found to give somewhat inaccurate results, and, the high pressure method has the added objection that a special autoclave is required to obtain the higher temperatures.

The apparatus 10, herein described in detail as. an illustrative embodiment of this invention, substantially eliminates these objectionable features. Said apparatus may comprise a stanchion 11 having a base portion 12 and upstanding rod 14. A

clamp 15 may be adjustably secured to said r0d:;70 14 in any desired adjustable position as by actuating the thumb screw limounted in a lug 18 integrally formedwith said clamp. Said clamp 15 is further formed with an integral arm 19 and an annular ringzportion 20. Dependingly supported '7 within said ring 20 is apbeaker 21 preferably made Removably, received 23 .adapted to rest on the lower wall or bottom 2410f said beaker. Said rack further comprises .anupstanding, elongated metal tube 25 made of .copper,1or. the like metal toprevent breakage.

.Said tube. 25 acts as. a protecting jacket for a The thermometer. 26 is preferably; graduated to 1-200 C; At substantially the mid-portion .thereofor below the cut outgportion 27 and ator similar metal, said disc being formed with a pluralityof spaced radial notches 29., The outer edge portions 30 of said disc between said notches,

are preferably slightly rounded upwardly or, up-

Suspended from saiddisc 28 in a manner hererinafterappearing are a plurality of glass pressuretubes 31. Each of said tubes 31 comprises an elongated tubular portion 32 having prefer- ..ably, a rounded bottom 33a. At its top, each of said tubes; 31 is formed .withan inwardly flaring portion 33 and. an outwardlyfiaring portion 34,

:thus providing a constricted neck 35. vThe inner inwardly flaring portion 33. The outer surface 43 of said head 42 is preferably ground so that when contacting the ground surface 36 of the tube, a substantially tight or leak-proof seal will be effected. Adjacent the upper end thereof, said stopper is formed with a plurality of spaced heads 44, respectively, separated by a neck portion 46. As clearly shown in Fig. 1, the neck portion 46 of said member 40 is received within the notch 29 and is suspended from said disc 28 since the head 45 thereof contacts the adjacent portions of the disc. The upturned portions 30 prevent the stopper from sliding off the disc. The outer diameter of the tubular portion 41 is smaller than the inner portion of the neck 35, so that the tube 31 may be lifted to permit the insertion of liquids and the like substances into the tube. It will be noted that upon lifting the tube 31 when suspended with the head 42 of member 40 tightly wedged against the neck 35 of the tube, the disc 28' will strike the head 44 and cause disengagement of said head to allow relative movement between said tube 31 and stopper member 40. Mounted on said base 12 is a Bunsen burner 39. The tube 31 as well as the stopper member 40 are preferably made of heavy Pyrex glass to withstand high pressures and temperatures.

One illustrated method of carrying out a test with the apparatus described above will now be described. For determining the urea content of blood, a tube 31 may be suspended from the disc 28, the entire rack 22 however, being removed from the beaker and placedon a table. The tube 31 is then raised to bring the stopper member 40 further into the tube and permit the insertion of liquid into said tube. 5 c. c. of a fil- -trate containing the water-soluble substances of the blood dissolved in water-known as Folin-Wu filtrate-and other reagents are now introduced into the tube by holding a tip of the pipette close to the lower end or head 42 of the stopper. That portion of the stopper may be washed down with 1 c. c. of water followed by 1 c. c. of normal sulphuric acid. The tube'may then be closed by lowering the same. The rack with the tube in suspension is then placed in'the beaker and an oil bath introduced into said beaker at such level that the liquid in the tube is somewhat below the level in the oil. Any oil of high boiling point will do. Nujol has been found to serve the purpose well as it produces very little odor when heated. The oil bath is then heated by means i of the Bunsen burner 39, to a temperature between 145 and 155 C., the steam will wedge the stopper head 42 tighter against the inner surface 36 of the tube. The higher the temperature, the greater will be the pressure within the tube, and the better the seal produced. Since the tube is made of Pyrex glass, high pressures and temperatures can be easily withstood without breakage or damage to the apparatus.

After the oil has been kept at about 150 C.

for about ten minutes, the tube is removed from the oil bath. When cooled, the stopper is released by pushing it further into the tube, and preferably 15 c. c. of water added followed by 3 c. c. Nessler solution. Water is then added to the 25 c. 0. mark and the tube shakento mix the contents. The quantity of urea may then be quickly and accurately determined by comparing the resulting solution in a colorimeter with a standard solution of ammonium sulphate. Thus a very simple, quick and accurate method of determining urea in the blood is provided.

The tube 31 and stopper member 40 may have a great number of uses other than that described for urea determination, wherever substances are to be heated under increased pressure. The particular construction of the stopper having a head within the tube and the constricted inwardly flaring neck portion adapted to receive said head automatically produce a tight seal upon increase of pressure within the tube.

With the apparatus shown, as many as six tests may be carried out simultaneously.

' It will thus be seen that there is provided a device in which the several objects of this invention are achieved, and which is well adapted to meet the conditions of practical use.

As various possible embodiments might bemade of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter here-;;

in set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:-

1. In combination, a tube having an inwardly flaring portion adjacent the top and an outwardly flaring portion extending from the inwardly flaring portion to provide a constricted neck, a stopper having a straight portion extending through, said neck and terminating at the lower end thereof in a conical shaped head contacting the inner surface of said inwardly flaring portion, said stopper being formed with a plurality of spaced heads adjacent the upper end thereof separated by a neck portion.

2. In combination, a tube having an inwardly fiaring portion adjacent the top and an outwardly flaring portion extending from the inwardly flaring portion to provide a constricted neck, a stopper having a straight portion extending through said neck and terminating at the lower end thereof in a conical shaped head contacting the inner surface of said inwardly flaring portion, said stopper being formed with a plurality of spaced heads adjacent the upper end thereof separated by a neck portion, the inner surface of said inwardly flaring portion and the outer surface of said conical head being ground.

3. In combination with a receptacle having a constricted neck, means effective upon increase of pressure within said receptacle for forminga seal therefor, said means comprising an elongated rod slidably extending through the opening in said neck and having an" enlargedhead at the bottom end thereof engaging said neck, said rod having a pair of spaced, enlarged portions on the upper end thereof, and .rn'ean's for suspending said receptacle comprising a stanchion, and a member on said stanchion havinga. notch receiving the portion of the rod .between said spaced, enlarged portions.

SAMUEL' LEO LEIBOFF.

Images