An Improvement in Recording Velocimeters.
Year: 1892

page_text: Date of Application, 8th Mar., 1892–Accepted, 9th Apr., 1892
COMPLETE SPECIFICATION.
An Improvement in Recording Velocimeters.
I, JOSEPH BOYER, of 244 Dickson Street, St. Louis, Missouri, in the United
States of America, Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
This invention relates generally to a means for varying the size of a conduit,
chamber or passage for a fluid to accurately accord with any change in the
temperature of the atmosphere or that of the fluid or the walls of the structure
with which the fluid is in contact. The invention however particularly relates to
means for automatically varying the size of a passage for the fluid in that class
of apparatus termed recording velocimeter, patented to me in Great Britain
February 1, 1887, No. 1,581.
In said apparatus a pump, chamber, piston and a fluid are so combined that the
velocity of a moving part is translated into pressure whereby the velocity is
indicated, and it may be, recorded. With these elements is also combined a passage
for the fluid from the pressure side of the piston to the opposite side, which passage
is of gradually increasing size so arranged with respect to the piston as to conserve
or guard the power when the velocity is low and as the power or speed-pressure
increased the passage is proportionately increased in size for the escape of a portion
of the fluid around or past the piston back to the well or suction side of the pump.
In such prior structure the size of the passage and its degree of gradual
increase was a fixed element formed in the first instance with regard to the normal
or mean temperature of the atmosphere, and so long as there was no considerable
variation in the temperature to which the fluid would be likely to be subjected, the
apparatus worked accurately, but as soon as a considerable variation did occur the
fluid would be influenced thereby and would flow more or less easily as the case
might be, whereby the resultant indication would vary from the true one to a greater
Tess
or
extent.
The object of my present invention therefore, among other things, is to obviate
this defective operation and to provide for an automatic compensation for any
variation in the temperature of the atmosphere to which the fluid may be subjected;
and to this end it consists in combining with a casing of metal containing the fluid
having a low ratio of expansion, of another metal having in respect thereto a high
ratio of expansion, the expansion or contraction of which will compensate for the
change in temperature of the fluid and more or less vary the volume of its flow.
A practical embodiment of the invention in one of its forms is shown in the
accompanying drawings in connection with the recording velocimeter constructed
after my said Patent.
In said drawings:-
Figure 1, is a sectional elevation of so much of the apparatus embodying the
invention as is necessary to its understanding.
Fig. 2, is a horizontal section of the same taken on the line 2, 2, of Fig. 1, and
Fig. 14 is a plan view of the apparatus on a reduced scale.
Fig. 3, is an elevation of the compensating valve removed from its scat.
Fig. 4, is a detailed horizontal section of a modified form of the valve.
Figs. 5 and 6, are similar views of other forms of the valve.
Fig. 7, is a similar view of another mode of varying the size of the opening for
the passage of the fluid.
Fig. 8, is a vertical section of another modification for the same purpose.
1
1
1
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page_text: to show it is of similar construction to that shown and set forth in my said Patent
similar letters of reference herein indicating corresponding parts in said-Patent.
The apparatus is contained by a casing B' having a top plate A, and a base or
bottom plate H. This casing with its top and bottom plates is preferably made of
cast iron or other similar metal having a low ratio of expansion, although for a
purpose to be hereinafter explained, distinct parts may be made of such metal while
the major portion is formed of other material.
The casing provides a chamber for a pump K of any of the usual forms, such
as piston or diaphragm-being in the present instance a rotary one, formed by a
pair of rolls KK", toothed or otherwise winged to intermesh and form propelling
or forcing blades for the fluid; and to the shaft of one of which rolls the power is
applied.
:
The casing provides another chamber acting as a cylinder J in which is mounted
a reciprocating piston J, the piston rod J of which extends outward through a
stuffing box in the top plate A and is connected to cause a movement of the
indicator as in said Patent.
The pump chamber or pump K is in communication with the cylinder J by two
passages E, E, the former leading from the eduction side of the pump to the
pressure or underside of the piston J, and the latter passage leading to the well or
induction side of the pump normally from the upper or non-pressure side of the
piston.
The passage E is interposed directly between the piston cylinder and the
induction side of the pump and extends substantially the vertical length of the
cylinder. In this direct connection between the piston cylinder and the pump,
while the passage is at all times open therebetween the piston acts to cut off more
or less of the extent of opening to the pressure side, and hence as it rises or falls
correspondingly increases or diminishes the extent of opening to the fluid.
in order to properly conserve or proportionately restrict the flow of liquid from
the cylinder, or back to the pump, the passage E, see Fig. 3, is formed with a
vertical opening which, starting from the bottom, is of a size that quickly increases
to its maximum width and then gradually decreases in width as the top is approached.
Thus the fluid forced by the pump by the passage E to the underside of the
piston will exert an upward pressure thereon sufficient to raise it to a more or
less extent, according to the speed at which the pump is run and the freedom with
which the fluid may escape past the piston by the passage E'. As the-piston is
raised, a corresponding portion of the passage E' is exposed below the piston and
opened to the escape of the fluid back to the pump; the extent of the opening of
which passage uncovered by the piston is such as to cause the proper extent of
movement of the piston coacting with the speed with which the liquid is delivered
by the pump.
To still further provide for the control of the flow of the fluid from the piston
cylinder J upon any change in the temperature of the atmosphere or of the fluid,
means is provided for automatically varying the size of the passage through which
the fluid passes.
And it is to be remarked in passing that while the means for this regulation or
compensation for the variations in the temperature in itself is the same in the several
modifications hereinafter suggested, the particular manner in which it
out in practice may be varied greatly.
may be carried
These means of compensation consist broadly in utilizing the difference in the
ratio of expansion of two metals, as that between the ratio of expansion of the
casing B of cast iron for instance and the ratio of expansion of a piece of zinc
controlling the size of the opening of the passage E'.
In Figs. 1 to 3, the preferred form of the invention is shown, in which the
passage E is provided in a cylindrical valve formed by two hinged semi-circular
wings 6, pivoted to a vertical stem 7 and adapted to oscillate on the stem to vary
the size of the opening of the passage. With each wing of this valve, formed of
a material of a low ratio of expansion, there is combined a piece of metal of a high

page_text: ratio of expansion such as zinc in the form of a pin 20 that extends inwardly
through a perforation in the casing with its end bearing against the rear of the
wing of the valve. The outer end of the head 21 of the pin is screw threaded to
engage with the threaded portion of the perforation, and to avoid any displacement
and leakage of the fluid past the pins there may be provided a tapered jam screw 22
screwed into the perforation tightly and, it may be, forced against the head of the
pin 20. From this construction it results that should the temperature of the
atmosphere increase, the zine pins 20 will expand in length to a greater degree than
the cast iron casing or of the valve, and being held firmly at their outer ends to the
casing will act inwardly at their free ends to force the mouths of the wings of the
valve together more or less according to the degree of expansion of the pins.
This movement of the valve wings will have narrowed the width of the passage or
of its entrance so as to control the flow of the liquid from the piston chamber back
to the pump.
In order to hold the valve wings against the ends of the expansion
pins and to return them to their normal condition upon the retraction of the pins a
spring 5 is connected to the wings upon the opposite side of the pivot stem for
this purpose. Of course one of the wings of the valve might be fixed and its pin
omitted while the other is movable by the expansion of a single pin against the
pressure of the spring.
In Fig. 4, the arrangement of the expansion pin and returning spring are
reversed. As shown, the pin 20 (or a number of pins) is inserted between the
pair of wings of the valve at one side of the pivot 7 so that upon expansion they
will move the valve wings to restrict the size of the passage E', while the spring 5
arranged upon the opposite side of the pivot opposes such movement and returns
the wings upon the retraction of the expansion pin.
In Fig. 5, instead of making the valve and expansion pins of separate pieces,
cach pin is provided at its inner end with a vertical strip 20 located at the entrance
to the passage E' and operating upon the expansion or retraction of the pins to
vary the size of said entrance or that of its passage.
In Fig. 6, the valve is of hollow cylindrical form split on one side to provide the
entrance for the passage E' and the opposite side perforated to allow the free flow
of the fluid back to the pump. This valve is formed of metal having a high ratio
of expansion such as zinc and being seated in a recess in the cast iron casing will
upon any increase in temperature expand in circular lines to a greater extent than
the casing, thus bringing the edges of the split side together so as to restrict or
narrow the opening between them as will be apparent.
In Fig. 7, a further modification of the invention is shown, wherein the piston
chamber is formed with a lining of metal having a high ratio of expansion such
as zinc. This lining is of cylindrical form divided at the passage E to form an
entrance thereto. Upon the expansion of the expansible lining to a greater degree
than the casing, the edges of the division will approach nearer each other and thus
allow the width of the entrance or of the passage E.
It is obvious that the pump chamber could be similarly lined and thus control the
opening of the passage into the well or suction side of the pump.
Another obvious modification of the invention is shown in Fig. 8, based upon the
construction shown in Fig. 7, of my said Patent, wherein the conical pin 1 is herein
made of the expansion metal such as zinc and thus upon expansion more or less
closes the opening 2 through the piston.
In each of the several examples of the invention the size of the passage or of its
entrance (it may be its exit) is controlled automatically by the expansion of a metal
having a high ratio of expansion with respect to the surrounding body of metal as
the casing B which has a low ratio of expansion, whereby the flow of liquid from
the piston cylinder to the pump is automatically varied according as the temperature
may vary.
Of course it is not essential that the entire structure, other than the high
expansion metal, should be formed of one material of low pressure, as it is simply

page_text: necessary that the low and high expansion metals should be associated so that the
differences of expansion of the one will have the controlling function.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
-claim is
1. A structure having a passage for the flow of the fluid and formed of material
having a low ratio of expansion, in combination with a controlling means for such
passage consisting of a metal having a high ratio of expansion, substantially as
described.
2. A structure having a passage for the flow of the fluid and formed of material
having a low ratio of expansion, in combination with a valve controlling such
passage, the movement of which is controlled by a metal having a high ratio of
expansion, substantially as described.
3. In a
recording velocimeter, the combination with the piston cylinder, the
pump chamber and a passage between the two formed wholly or in part of a
material having a low ratio of expansion, of a controlling means for said passage
governed by a metal having a high ratio of expansion, substantially as described.
4. In a recording velocimeter, the combination with the piston cylinder, the
pump and the passage between the two formed of a material having a low
ratio of expansion, of a valve interposed in said passage, the movement of which
is controlled by a metal having a high ratio of expansion, substantially as
described.
5. The combination with the piston cylinder, the pump and the passage between
the two, of a valve interposed in said passage and an adjustable metal pin controlling
the movement of said valve and having a high ratio of expansion, substantially as
-described.
6. The combination with the piston cylinder, the pump and the passage between
the two, of a valve composed of two hinged wings interposed in said passage and a
pair of metal pins abutting said wings having a high ratio of expansion, substantially
.as described.
7. The combination with the piston cylinder, the pump and the passage between
the two, of a valve composed of two hinged wings interposed in said passage, a
pair of metal pins abutting said wings having a high ratio of expansion and a
spring for holding the wings against the pins, substantially as described.
8. In a recording velocimeter, the combination of the piston cylinder, the pump
and a passage between the two, the opening of which, commencing at one endl
quickly increases to its maximum width and gradually decreases as it approaches
the opposite end, substantially as described.
9. In a recording velocimeter, the combination of the piston cylinder, the pump
and a passage for the liquid interposed directly between the piston cylinder and the
pump, the extent of opening of which passage is governed by the extent of
movement of the piston, substantially as described.
Dated this 7th day of March 1892.
H. B. BARLOW,
17, St. Ann's Square, Manchester, Agent for Applicant.