A METHOD OF AND APPARATUS FOR MEASURING THE VARIATIONS IN THE LEVEL OF THE SEA OR OF A RIVER, LAKE WELL OR OTHER PIECE OF WATER
Year: 1885

page_text: We ADAM FREDERIK WIVET PAULSEN, Director of the Metereological Institute,
Copenhagen, PETER KRISTIAN PRYTZ, Sub director of same, and GEORG ADOLPH
RUNG Cand. Mag and Electrician, all of 85 Store Kongensgade Copenhagen in
the Kingdom of Denmark do hereby declare the nature of said invention for
"A METHOD OF AND APPARATUS FOR MEASURING THE VARIATIONS IN THE LEVEL
OF THE SEA OR OF A RIVER, LAKE WELL OR OTHER PIECE OF WATER," and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
The advantages of this Danish pneumatic water level gauge are that the level
of the water along the coast, in a well or in any other place from a point not
immediately contiguous thereto, and that this gauge does not require costly non-
freezing wells such as now in use and in which the level is found by means of a
float.
The invention will be best understood by reference to the accompanying
drawings.
From the place whose depth below the water level d d Figure 1 is to be measured
we lead a pipe a having a narrow opening at B up to the observatory or place A
where the level is to be read off or registered. At this place it divides in two
branches b and c of which one leads to a pressure gauge and the other to an air
pump or other apparatus supplying compressed air, whereby a constant but very
slow current of air is sent through the pipe and its aforesaid narrow opening and
from which it escapes up through the water as air bubbles. The water is thus
prevented from entering the pipe, and the air current is made so slow that there
inay be said to be always equilibrium between the pressure of the water at the
aforesaid narrow pipe opening at B and the pressure of the air in the pipe. The
height of water level d d above that opening at B will be proportional to the air
pressure in the pipe. In apparatus required to give great exactitude the specific
weight of the water must be taken into account. This is attained by providing an
extra pipe conduit such as e Figure 2 parallel with the other pipe conduit but
terminating at a higher (or lower) point C below the water level than the first
named pipe conduit and also supplied with air pressure. The difference in the air
pressure in the two pipes a and e will depend upon the specific gravity of the

page_text: water and may serve to correct the water level which is read off or registered on
the pressure gauge according to variations in the specific gravity. By causing the
water end of the first named pipe a to terminate in a very fine horizontal pipe coil
as shown at Figure 3 the deleterious influence of sudden alterations in the water
level will be prevented as the zero of the apparatus will not alter so long as the
water can penetrate into the aforesaid coil.
The air to be pressed through the piping may be of various kinds. It is however
of special advantage to use hydrogen, because it is easy to produce a slow and
even current of this gas and because it will keep the outlet opening into the water
free from plants and animalculæ.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is
First: The application for measuring the water level at a certain place of a
constant or previously to the observation produced slow current of air or gas
through a pipe and out into the water at such place at a certain distance below the
water level in connection with a pressure gauge of any suitable construction
substantially as set forth.
Second: A water level measuring apparatus consisting of a pipe a which is
traversed by a constant or previously to the observation produced slow current
of air or gas that in slow bubbles passes out into the water from the point whose
depth below the water level is to be measured in combination with a pressure
gauge of any suitable construction connected to the pipe a substantially as described
with reference to the accompanying drawings.
Dated this Fifth day of February 1885.