Improvements in Apparatus for Indicating the Pressure or Head and Facilitating the Measurement of Liquids Flowing through Pipes or the like.
Year: 1888

page_text: Date of Application, 17th Apr., 1888
Specification Accepted, 13th July, 1888
United States of America, Engineer.]
Improvements in Apparatus for Indicating the Pressure or Head
and Facilitating the Measurement of Liquids Flowing through
Pipes or the like.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature of
this invention and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
My invention is based upon the well known property of liquids when flowing
through a diverging ajutage or Venturi tube, to exercise a sucking action through an
aperture in the pipe or tube, located at the point of the smallest cross-section of the
latter; and upon the further fact that such sucking action increases and decreases in
intensity with the increase and decrease of the velocity of the stream flowing through
the pipe. I have discovered that the velocity of the flowing stream can be determined
by locating such ajutage or Venturi tube in the pipe or tube forming the conduit of
the liquid to be measured, ascertaining by means of suitable gauges the height of
a column of liquid capable of being lifted by the sucking action of the ajutage, and
also the head of the liquid in the cylindrical portion of the pipe or tube and then
computing the discharge through the smallest cross-section of the ajutage, as though
it took place under a head equal to the difference in level between said column of liquid
and the head of the liquid in the cylindrical portion of the pipe or tube, for which
find a coefficient nearly equal to One. The velocity of the stream at the smallest
cross-section of the ajutage being thus determined and the area of said cross-section
being known, the quantity of liquid flowing therethrough in cubic feet per second can
be readily ascertained in the usual manner by multiplying the one by the other.
By this method therefore I am able to measure liquids flowing through a pipe by
utilizing the method of computation of the discharge of liquids through an orifice under
a material head, but without losing any material portion of the total head of the
077

page_text: liquid flowing through the pipe, which has been the main difficulty to overcome in all
plans for the metering of large quantities of water or other liquids when flowing
through the larger sizes of pipes or tubes.
For the purpose of facilitating the measurement of liquids by this method I have
devised the apparatus hereinafter fully described aud particularly pointed out in the
claims.
Referring to the drawing in which like letters designate like parts in the several
figures,
Figure 1 is a longitudinal sectional view of a pipe provided with said apparatus.
Figure 2 is a similar view of a slightly modified form of the apparatus.
Figure 3 is a like view of the apparatus as applied to the outlet of a tank or
reservoir.
Figure 4 is a view similar to Figures 1, 2 and 3, showing still another modification
of certain portions of the apparatus.
Figure is a transverse section taken upon line - in Figures 1, 2 and 3.
Figure illustrates an apparatus for indicating and recording directly the rates of
flow of the liquid through the meter and also for furnishing the data from which the
quantity of liquid passing through the meter during any given space of time may be
computed.
Figure 7 is a side view of the apparatus shown in Figure 6.
Figure 8 is a horizontal section taken upon line y-y of Figure 7.
In Figures 1 and 2 the letter A, designates the pipe or tube the quantity of liquid
flowing through which it is desired to measure, the direction of the flow of the liquid
being indicated by the arrows. At any desired point in said pipe or tube is located
the metering apparatus, which I call a Venturi meter, composed, as shown in Figure 1,
of a converging section B. and diverging section B' said sections being connected to
the abutting ends of pipe A. by suitable flanges and bolts as shown. In Figure 2.
the converging section of the meter instead of being in form of a frustrum of a cone
as in Figure 1 is made by the revolution of an ogee curve about the axis of pipe A. as
shown at 12. The two sections of the meter are connected by a throat piece C. the
bore of which increases slightly in diameter from its central cylindrical portion toward
each end, the ends of said throat piece and the adjacent ends of the converging and
diverging sections of the meter being connected by suitable flanges as shown. At the
point of its smallest diameter said throat piece is provided with orifices 'e, preferably
four in number, as shown in Figure 4, extending through its shell, into an air
chamber extending entirely around the throat piece, whereby communication
between the interior of the throat piece and the air chamber is established: The
suction created by the liquid as it flows through its ajutage will be exerted upon the
air chamber through each of the passages simultaneously, and therefore the degree
of suction created can be very accurately determined by means of a suitable guage
connected with the air chamber. It is obvious that by connecting a glass tube E. at
its lower end to the throat piece in such manner that communication between the
bore of the tube and the air chamber is established, and connecting another tube F.
in a similar manner to the cylindrical portion of pipe A. as shown in Figures i and 2,
and continuing said tubes upwardly to the normal level of the liquid at the source
from which said pipe A. leads, the liquid will stand in said tubes E. F. and at said
source, at the same level, so long as the liquid remains stationary, that is to say does
not flow through pipe A. It is equally obvious that as soon as the liquid commences
to flow through pipe A. the suction created through the passages c and air chamber d
will cause a depression in the level of the column of water in tube E. which depression
will increase with the increasing velocity of the flow of the liquid through said pipe.
The difference in lead, therefore, between the liquid at the point of smallest cross-section
of the throat piece, and at the point in the cylindrical portion of pipe A. selected for
the position of tube F. will be indicated by the difference between the level of the
column of liquid in tube E. and that in tube F, which can be determined at once by
providing said tubes with scale marks as shown. The head of the liquid at the center
of the throat piece being thus determined the velocity of the stream at that point:can

page_text: be readily computed by the well known equation v =
2gh in which v.represents the
velocity in feet per second, g represents the space through which a body falls by the
action of gravity in the first second of time, and h represents the head already spoken
of in feet, and having ascertained the velocity, the area of the throat piece at its
center being known, the quantity of liquid flowing therethrough in cubic feet per
second, can be at once determined as previously stated.
While such an arrangement of the apparatus would answer very well for the
purposes of experiment, it would be impracticable, in most instances, for actual use, to
continue the tubes E. F. to such a height, and, therefore, the form of apparatus
shown in Figure 1 will be found to be better adapted for general usc. In said figure
the tube F. is provided at its upper end with a pressure guage G. which may be of
any of the common forms of such guages, its function being to register the head
of the liquid in the cylindrical portion of pipe A. or, in other words, the weight of the
column of water capable of being lifted by the pressure exerted by the liquid within
said pipe. Tube E. is bent into siphon form and the limb H. thereof has its lower
end immersed in mercury contained in the vessel I. while a valve K. is located in the
limb E. as shown, to govern the admission of air into the tube.
When the valve K. is
open it permits the normal pressure of the atmosphere to be exerted upon the
column of water within tube E. in the same manner as if said tube were entirely
open at the top. When said valve K. is closed the tube E. H. forms a vacuum guage
and its function is to register the degree of suction at the throat piece when said
suction has reduced the level of the column of water in tube E. or depressed what is
known to engineers and others as the hydraulic gradient, below the upper surface of
the throat piece, where of course its level could not be observed by means of the
tube E. alone. As soon as said hydraulic gradient is depressed by the suction below
the level of the top of the throat piece with valve K. open, said valve is closed and a
vaccuum being then created in the tube E. H. the mercury at once rises in the
limb H. and the true depression of the hydraulic gradient can be found in the
following manner.
Suppose the guage F. G. and the vaccuum guage H. 1, to read from a common zero
or basis of levels. Then ascertain the elevation of the top of the bore of throat
piece C. on this same scale of heights, and imagine the readings of the vaccuum guage
-reduced to the height of an equivalent column of water-subtracted from this
elevation of the crown of the throat piece. The low point thus found is the locus of
the hydraulic gradient at the smallest cross-section of the throat piece. The true
depression of the hydraulic gradient being thus determined, the difference between its
level and that of the level of the column of water in tube F. as indicated by guage G.
will, as previously stated, give the head of the liquid at the point of smallest cross-
section of the throat piece, afr which the quantity of liquid passed therethrough can
be ascertained as previously described.
It will be observed that, by the use of this simple apparatus, I am enabled to
accurately guage the quantity of liquid flowing through a pipe even when the latter
is located beneath the surface of the ground, such as a street main, and in other such
partly inaccessible positions, and without, as previously stated, losing any material
portion of the total head of the liquid flowing through the pipe.
As shown in Figure 3 the apparatus is applied to the outlet opening of a tank or
reservoir L. in which case as the head at said opening is readily obtainable by actual
measurement within said tank or reservoir, the tube F. and guage G. are omitted, the
operation of the apparatus otherwise being the same as that previously described.
In Figure 5 I have shown the tubes E. F. as being united by the U shaped
bend M. containing mercury at its lowest point, said U shaped portion being provided
with scale marks as shown. By this arrangement of the tubes a compound guage is
formed by means of which the difference in head of the liquid at the points where the
tubes E. F. are located will be indicated by the movement of the column of mercury
in the tube M.
In Figures 6, 7 and. 8, I have shown an apparatus for indicating and making a
continuous and automatic record of the rates of flow through the meter besides furnishing

page_text: "'
the data from which the cubic quantities passing the meter may be computed. In this
form of invention the tubes E. F. are prolonged and are led to the indicating and
recording apparatus which may be located at any convenient point. The indicating
apparatus is composed of two glass tubes N. O. half filled with mercury and connected
at the bottom by a pipe P. made of iron or other material which the mercury will
not corrode. At their upper ends said tubes N. O. are rigidly connected to hollow
arms R. S. respectively, which arms are connected together at their opposite ends
but have no interior communication wsth each other. I prefer to make the arms R. S.
integral with each other as shown, see Figure 8, a partition T. separating their
interiors. A short tube extends laterally from arm R. at the point of its junction
with arm Sand a similar tube s leads from arm S. in the opposite direction the axes of said
tubes and s being in the same straight line. The ends of tubes E. F. are brought
opposite to each other horizontally in the same straight line, and the end of the tuber
is inserted within the end of tube F. while the end of tubes is inserted within the end of
tube E. stuffing boxes s¹ making the connection between said tubes perfectly tight while
permitting a free revolving movement of said tubes »,s within said tubes F. E. The tubes, s
thus form trunions upon which the arms R. S. and tubes N. O. are supported and are
permitted to have a free oscillating movement. Braces give increased rigidity to
the oscillating guage N. O. R. S. and a pointer t' is secured to the lower end thereof
as shown. A graduated are islocated adjacent to the path of movement of pointer t
the zero point of which is located at one of the extremities of the movement of said
pointer as shown. Counter balance weights U. V. are connected to arms R. S. as
shown or to any part of the oscillatory guage which weights are so adjusted that when
the mercury stands at the same level in tubes N. O. pointer will be retained at the
zero point of the arc, and at one extremity of its movement. Inasmuch as the
mercury can stand at the same level in said tubes N: O. only when the pressure in
tubes E. F. is equal, and as the pressure in said tubes can never be equal while liquid
flows through the pipe A. as hereinbefore explained, it will be obvious that when
the greater pressure in tube F. causes a portion of the mercury in tube N. to pass
through pipe P. into tube O. the guage N. O. R. S. will be caused to swing, in seeking
a state of stable equilibrium, the amount of which movement, corresponding to the
difference in pressure in tubes E. and F. will be indicated by the new position of
pointer t¹ upon are t².
If now the marks upon are be made representative of the cubic quantities per
unit of time, by the methods of computation hereinbefore described, it is equally
obvious that pointer will indicate upon are the above named cubic quantities per
unit of time passing the meter at any moment of time.
In order to make a permanent record of the readings of pointer t¹ I pivotally connect
thereto the end of a rod 3, the opposite end of which rod supports a pen, pencil or
similar marking instrument, and cause said pen or pencil to bear upon the paper of
any of the well known forms of recording instruments in which a sheet of paper is
caused to have a uniform revolving movement by suitable clock work mechanism, as
represented for example at W. Without further description it will be understood by
those skilled in the art to which my invention relates that as the paper sheet is revolved
the movements of pointer t¹ will be traced thereon by the pen or pencil, and that such
traced line upon the paper together with a line drawn upon the paper corresponding to
the zero mark on are twill constitute a permanent record of the action of the meter.
I do not wish to limit myself to the particular devices shown and described for
measuring the head of the liquid at the point specified, as it is obvious that the
construction of said devices can be greatly varied without departing from the spirit
of my invention.
Having now particularly described and ascertained the nature of the said invention
and in what manner the same is to be performed as communicated to me by my
foreign correspondent I declare that what I claim is :-
1. As a means for facilitating the measurement of liquids by the method herein
described, and an ajutage or Venturi tube located in such manner that the liquid is

page_text: caused to flow therethrough, said ajutage being perforated at the point of its smallest
cross-section, whereby suction will be created at such point as the liquid flows through
it, and a suitable guage for measuring the intensity of said suction, substantially 'as and
for the purpose set forth.
2. As a means for facilitating the measurement of liquids flowing through a pipe
by the method herein described, an ajutage or Venturi tube located in said pipe, said
ajutage being perforated at the point of its smallest cross-section, whereby suction
will be created at such point as the liquid flows through the pipe, and a suitable
guage for measuring the intensity of said suction, arranged and operating substantially
as set forth.
3. As a means for facilitating the measurement of liquids flowing through a pipe
by the method herein described, an ajutage or Venturi tube located in said pipe, said
ajutage being perforated at the point of its smallest cross-section, whereby suction
will be created by the liquid as it flows through the pipe, a suitable guage for
measuring the intensity of said suction, and a guage for indicating the head of the
liquid in the cylindrical portion of the pipe adjacent to said ajutage, arranged and
operating substantially in the manner set forth.
4. As a means for facilitating the measurement of liquids flowing through a pipe
by the method herein described, an ajutage or Venturi tube located in said pipe, said
ajutage comprising a throat piece having at the point of its smallest cross-section a
series of perforations, an air chamber surrounding said throat piece and communi-
cating therewith by means of said perforations, a vertically disposed tube communicating
with said air chamber, and a guage for indicating the level of the liquid in the tube,
substantially as and for the purpose set forth.
5. As a means for facilitating the measurement of liquids flowing through a pipe
by the method herein described, an ajutage or Venturi tube located in said pipe, said
ajutage comprising a throat piece having at the point of its smallest cross-section a
series of perforations, an air chamber surrounding said throat piece and communicating
therewith by means of said perforations, a vertically disposed tube communicating
with said air chamber, a valve governing the admission of air to said tube, a guage
for indicating the level of the liquid in said tube when said valve is open, and a vacuum
guage for indicating the suction created in said tube by the passage of the liquid through
the ajutage when said valve is closed, arranged and operating substantially in the
manner and for the purpose set forth.
6. The liquid metering apparatus herein described consisting of the converging and
diverging pipe sections B. B located in pipe A. throat piece C. uniting said sections,
said throat piece having the series of perforations c, and having air chamber d com-
municating with the perforations c, tube E. communicating with said air chamber,
tube F. communicating with pipe A. at a point adjacent to pipe section B. and suitable
guages for indicating the level of the liquid in said tubes E. F. arranged and operating
substantially in the manner set forth.
7. The liquid metering apparatus herein described consisting of a conduit A. having
the converging and diverging portions B. B₁ throat piece C. uniting the ends of said
portions B. B said throat piece having a bore increasing slightly in diameter from a
central cylindrical portion toward each end and having in its central cylindrical
portion the series of perforations c, air chamber d communicating with the bore of the
throat piece by means of the perforations c, tube E. communicating at one end with
said air chamber and having its opposite end bent to form the limb H. the end of
which limb is immersed in mercury, tube F. communicating at one end with conduit A..
adjacent to the diverging portion B. thereof, and a pressure guage, as G. connected
with said tube at its opposite end, arranged and operating substantially as and for the
purpose described.
8. The combination with pipe A. and tubes E. F. of a pressure guage pivotally
connected with the ends of said tubes in such manner that said guage will be caused
to swing upon its pivot by a difference in pressures in said tubes, and a device
connected with said guage for indicating the amount of its movement substantially as
described.

page_text: 9. The combination with pipe A. and tubes E. F. of a pressure guage pivotally
connected with the ends of said tubes in such manner that differences of pressures in
said tubes will cause said guage to swing upon its pivot, an indicator for indicating
the amount of the movement of said guage and a recording mechanism for making a
permanent record thereof, substantially as set forth..
10. The combination with the tubes E. F. of hollow arms R. S. mounted upon said
tubes by means of the tubular trunions r, s, glass tubes N. O. rigidly connected at
.their upper ends to said arms, said tubes being connected together at their lower ends
and containing mercury, pointer and a graduated scale located adjacent to said
pointer, substantially as and for the purpose described.
11. The combination with tubes E. F. and pressure gnage N.O. R. S. pivotally
mounted upon said tubes of the recording mechanism W.³ connected to said guage
and operating substantially as described.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C.,
Agents for the Applicant.