SU1487864A1 - Chamber for determining oxygen consumption by small laboratory animals - Google Patents

Description

The invention relates to biology. The chamber contains a sealed container 1 for animals, a section 2 for absorbing carbon dioxide and moisture, an oxygen tank 4, a vessel 7 with a replacement liquid 8, a pressure gauge 6. The tube 9 is made with ascending 12 and descending 11 elbows of various lengths. The upper portion of the tube is passed into the oxygen reservoir 4. The lower end of the ascending knee 12 'of the tube is immersed in the replacement fluid 8, and the lower end of the downward (shorter) elbow 11 inside the oxygen reservoir 4 is set higher than the level of the replacement fluid 8 in the vessel less than the height of the capillary rise of this fluid in the tube 9. These design features of the camera allow you to realize the processes of automatic replacement of oxygen with a liquid and maintain almost constant pressure during ec to experiments without a laboratory. '2 Il.

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The invention relates to laboratory equipment for research in the field of biology and physiology, in particular to devices for determining the total oxygen consumption of laboratory animals, and can be used in biological experiments and studies, including those performed in the expeditionary conditions.

The purpose of the invention is to compensate for the consumption of oxygen and control its quantity.

FIG. 1 shows a camera; in fig. 2 - embodiment of the tube.

The chamber (Fig. 1) contains a tank 1 for animals with a section 2 placed under it to absorb carbon dioxide and moisture, a grid 3 separated from the tank 1, an oxygen tank 4 connected to the tank for animals pipeline 5, a pressure gauge 6 and a vessel 7 with a replacement liquid 8 connected to the oxygen reservoir 4 by a tube 9 with capillaries 10. The end of the tube 9 with capillaries 10 located inside the oxygen reservoir 4 is set above the level of the replacement fluid 8 in the vessel 7 by an amount less than the possible height of the replacement fluid in a capillary tube with a given internal diameter. Tube 9 has a descending I 1 and ascending 12 knees.

The camera works as follows.

The test animal inside the sealed container 1 absorbs oxygen during breathing and releases carbon dioxide, which passes to section 2 through grid 3 and is absorbed in it (for example, using KOH alkali). At the same time inside the sealed container 1 and connected to it through the pipeline 5 oxygen tank 4 creates a pressure differential relative to the surrounding atmosphere, which can be monitored by a pressure gauge 6 (usually a water pressure gauge). After reaching the value of the pressure drop corresponding to the height of the end of the descending knee 11 relative to the level of the replacement fluid 8 (for example, water), in the vessel 7 this fluid begins to flow into the oxygen tank 4 through the tube 9 and replace the volume of oxygen consumed in the chamber and displace it tank 4 in the tank for animals 1 through the pipe 5 in an amount corresponding to its consumption during breathing. As a result, there is an automatic stabilization of the pressure and composition of the gaseous medium in the tank for animals 1 during the experiment. After the set time has elapsed, the intensity of oxygen consumption is estimated by measuring the amount of replacement fluid that has flowed from the vessel 7

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in the oxygen tank 4, and the determination of oxygen consumption per unit of time.

The pressure drop between the gaseous medium and the surrounding atmosphere will be equal to the sum of the pressure of the replacement liquid column with a height equal to the rise of the end (output section) at the outlet of the tube 9 relative to the liquid level in the vessel 7, and the dynamic pressure drop caused by the flow of liquid. Providing a given (allowable) dynamic pressure drop is made by jointly selecting capillary parameters - length I, radius g and number of capillaries Ν, taking into account the O2 flow per time unit <2, the allowable pressure drop Δρ and the viscosity coefficient of the replacement fluid η, based on the condition Λ ^ δί ^ -η / / τΐΓ * Δρ, obtained from the Poiseuille formula Ts = l · Γ ⁴ Δρ / 8 (η. For example, assuming that the average oxygen consumption of small laboratory animals (rat) is about 0.05 cm ³ / s, and the allowable dynamic pressure drop of 5 mm - water. Art., floor It is assumed that with a length of the polycapillary region £ = 30 mm and / 7 = 15 (approximately this number of capillary tubes can be installed in a tube-hose with a diameter of about 10 mm), the capillary tubes used should have a diameter

> 2 DC "0.53 mm (when using ^ν / 7 · π · Δρ

as a replacement fluid for water, v. which η = 0.01). The elevation of the replacement fluid (water) in such a capillary will be about 50-55 mm, so that the magnitude of the elevation of the lower end of tube 9 relative to the level of fluid 8 in vessel 7 is decisive. The value of the static pressure drop between the gas medium of the chamber and the atmosphere can be set to about 10 mm, which gives a total difference of about 15 mm aq. Art. With a vessel diameter of 7 of the order of 25 cm, the change in the level of liquid 8 in it over 1 hour and the corresponding change in pressure drop will be negligible (up to 3-4 mm).

Claims (1)

Claim A chamber for determining oxygen consumption by small laboratory animals, containing a tank for animals, a section with a grid placed under it to absorb carbon dioxide and moisture, an oxygen tank connected by a pipeline to the tank and having an input for supplying a replacement liquid, a pressure gauge connected to the tank for animals , and a vessel with a replacement fluid, characterized in that, in order to compensate for the oxygen consumed and control 1487864 five for its quantity, the vessel with the replacement fluid is connected to the tube, which is downward. and ascending knee when 6 this downward knee is equipped with capillaries, and the level of replacement fluid is set below the level of the bend of the pipe. FIG. 2