SU49445A1 - Instrument for determining the specific gravity of liquids - Google Patents

Description

Instruments for determining the specific gravity of liquids are already known, consisting of two piezometric tubes immersed at different depths in the test fluid connected to a differential pressure gauge.

The proposed instrument also uses two piezometric tubes attached to a differential pressure gauge, but unlike the known instruments, the oapa of these tubes are immersed in a reference fluid, and a friend at the same depth in the test fluid. This makes it possible to arbitrarily shift the zero of the scale of the measuring instrument by changing the specific gravity of the reference fluid and simplifies the temperature correction of the instrument.

The drawing shows a schematic view of the proposed device.

The device consists of two concentric-. vessels 7 and 2, in each of which a piezometric tube 3 or 4 is immersed, ending with a cap 5 or b. The outer vessel 7 is filled with a reference liquid, the temperature expansion coefficient of which is the same as the expansion ratio of the measuring liquid. The measured liquid passes through the coil 7, where it receives the temperature of the reference liquid and enters from below into the internal vessel, from where it is removed through the overflow opening. Fluid levels are kept constant and the same. The measurement is performed by two manometers, of which one measures the pressure drop created between the two tubes, the author measures the pressure in the tube immersed in the reference fluid.

If the immersion depth of the piezometric tubes I, then the differential pressure gauge shows the difference

D / g I (,)

where 7 is the unit weight of the test liquid at temperature t, 7i is the specific gravity of the reference liquid at the same temperature. The pressure of the column of the reference fluid will be A // at the Designation - t - 15, and also taking into account that

Y. TU (1 + x). T, Ti5 (1 + a-)

and expressing f, and Y / in terms of the corresponding quantities, pseluchim:

DL I () (ti-7th) L I (1 + at) ,,

from where

T 16.

whence the desired specific gravity is determined, since on the right-hand side all values are known.

The subject matter of the invention.

Claims (2)

1. A device for determining the specific gravity of liquids using two piezometric tubes connected to a differential pressure gauge, characterized in that one of the piezometric tubes is immersed in the reference liquid, and the other at the same depth in the test subject for the purpose of displacement zero gauge scale by changing the specific gravity of the reference fluid. 2. The form of the instrument according to claim 1, characterized in that, in order to equalize the temperature of the reference and test liquid, a coil placed in the reference liquid is used to pass the test liquid through it before entering the vessel with the piezometer.