Abstrict A flow meter includes a transparent tubular housing in which an
indicator in the form of a piston having a radially expanded edge
cooperates with a tapered inner peripheral wall portion of the housing.
The housing can include scale indicia of flow rates coinciding with
positions of the indicator edge. In addition, a temperature sensitive
label providing a visible indication of fluid temperature can be
orthogonally aligned with respect to the flow rate scale to permit
accurate placement of a graphic overlay exhibiting representations
of a different fluid characteristic which varies with changes in
the flow rate and temperature of the fluid within the ranges indicated
by the meter. Projection of the temperature indication to the indicator
edge identifies a particular value for the fluid characteristic
shown on the graphic representation by mere observation. The inner
periphery of the housing includes a radially expanded portion at
one end to provide a bypass for fluid at flow rates greater than
the normal range for the meter.
Claims What is claimed is:
1. A fluid flow meter comprising:
a housing comprising a peripheral wall defining an elongated hollow
chamber therein and having a fluid inlet at a first end of said
chamber and fluid outlet at a second end of said chamber; said peripheral
wall including at least a wall portion thereof formed of a visually
transparent material;
a chamber wall located in said housing and formed across one of
said ends of said chamber, said chamber wall including at least
one aperture therethrough;
a support body located in said housing and retained adjacent the
other of said ends of said chamber, said support body including
at least one aperture therethrough;
a rod extending between and mounted to each of said chamber wall
and said support body;
a piston including a piston portion defining a linear peripheral
demarcation aligned in profile perpendicularly to a longitudinal
axis of said chamber; said piston also including a bore slidably
receiving said rod therein, such that said piston is displaceably
carried by said rod in a position so that said demarcation is visible
through said transparent portion of said peripheral wall, and said
piston portion circumferentially abuts against said peripheral wall,
at said first end of said chamber; and
means for resiliently biasing said piston towards said first end
of said chamber;
wherein said peripheral housing wall includes a first inner surface
tapering radially outwardly from said first chamber end, and a second
inner surface adjacent said support body and between said support
body and said chamber wall which is radially outwardly recessed
from said first inner surface so as to form a bypass about said
piston when the rate of flow exceeds a predetermined rate; and
wherein said peripheral housing wall is imperforate between said
chamber wall and said support body, such that said chamber is circumferentially
imperforate between said chamber wall and said support body.
2. The invention as defined in claim 1 and further comprising scale
indicia aligned along the longitudinal axis of said housing and
visible exteriorly of said housing.
3. The invention as defined in claim 2 and further comprising a
temperature sensitive overlay aligned with said scale indicia.
4. The invention as defined in claim 1 wherein said linear, peripheral
demarcation comprises a radially expanded edge of said piston.
5. The invention as defined in claim 4 wherein said at least one
peripheral portion of said piston comprises said radially expanded
edge.
6. The invention as defined in claim 5 wherein said indicia includes
a base line aligned at the point at which said edge abuts said peripheral
wall.
7. The invention as defined in claim 6 and further comprising a
temperature sensitive label secured to said housing at said base
line.
8. The invention as defined in claim 1 wherein said housing includes
scale indicia along said transparent peripheral wall portion.
9. The invention as defined in claim 1 wherein said housing comprises
a tubular body, a first end cap at said first end of said chamber,
a second end cap at said other end of said chamber and means for
securing each of said end caps within said tubular body.
10. The invention as defined in claim 9 wherein said body is transparent.
11. The invention as defined in claim 9 wherein each end cap includes
fluid passage means for communicating between said chamber and the
exterior of said housing.
12. The invention as defined in claim 11 and further comprising
means for sealing each of said first and second end caps to said
housing.
13. The invention as defined in claim 1 wherein said piston includes
a substantially cylindrical stub end, wherein said means for resiliently
biasing comprises a coil spring, and wherein said coil spring fits
over said stub end of said piston.
14. The invention as defined in claim 13 wherein the axial end
of said stub end is tapered.
15. The invention as defined in claim 13 wherein the axial end
of said stub end is tapered.
16. The invention as defined in claim 1 wherein said support body
includes a substantially cylindrical stub end, wherein said means
for resiliently biasing comprises a coil spring, and wherein said
coil spring fits over said stub end.
17. The invention as defined in claim 1 adapated to indicate the
value of a diverse nontemperature characteristic of a fluid flowing
therethrough, said diverse characteristic being different from the
rate of flow indicated by said linear portion; wherein said meter
further comprises:
a material responsive to the temperature of said fluid in thermal
contact with said fluid so as to provide a visible indication correponding
to the temperature of said fluid, disposed adjacent said linear
piston demarcation; and
a graphic indicium of said diverse nontemperature fluid characteristic
disposed adjacent both of said linear piston demarcation and said
temperature responsive material, said graphic indicium including
a plurality of value indicia each designating a particular value
of said diverse fluid characteristic as a function of both the value
of fluid flow and the visible indication of fluid temperature provided
by said temperature responsive material;
such that said linear piston demarcation and said temperature responsive
material together visibly designate a particular one of said values
of said diverse fluid characteristic which can be directly visually
perceived from said graphic indicium.
Description BACKGROUND OF THE INVENTION
I. Field of the Present Invention
The present invention relates generally to meters for measuring
the flow rate of fluid in a fluid system, and more particularly
to such a meter having perceptible indicators for displaying an
indication of fluid characteristics related to the temperature and
flow rate of the fluid.
II. Description of the Prior Art
There are many types of previously known flow meters which provide
a visual indication of the flow rate of a fluid in a fluid system.
For example, in a moving vane type flow meter, a vane is displaced
and oriented in a predetermined position corresponding to the flow
rate of the fluid passing through the meter. The vane may be linked
to an arm extending across the face of a scale so that the position
of the arm on the scale provides a visible indication of the flow
rate of the fluid. Quite often, the indicator is positioned outwardly
of the flow meter so that the indicator is visible from the exterior
of the flow meter housing. As a result, the linkage between the
vane acted upon by the fluid and the indicator can add a substantial
amount of weight and inertia to the vane mechanism, thus reducing
the efficiency and accuracy of the reading provided by the indicator.
Of course, other indicator means may also be external to the flow
meter such as a digital display device. However, such devices are
substantially more complex and often more expensive than simple
mechanical linkages and indicators. In any event, previously known
flow meters are of limited use in that they convey no information
as to other characteristics of the fluid such as temperature, or
characteristics of a fluid which may change in response to changes
in temperature or flow rate.
In addition, although there are known means for measuring the temperature
of a fluid, previously known thermometers are not well adapted for
use with flow meters. As a result, the empirical data which is provided
by the previously known flow rate meters and temperature indicators
must be analyzed and calculated according to standard material property
relationships in order to obtain information about other characteristics
of the fluid in the system. For example, in order to establish the
net heat flow rate between two points in a fluid system, substantial
calculations must be performed utilizing the data from the previously
known flow meters and temperature indicators. Similarly, when the
viscosity of the fluid is affected by changes in temperature of
the fluid, it may be necessary to perform complex calculations to
determine the viscosity of the fluid under existing fluid system
conditions. While such calculations can be handled by trained engineers,
such a process can be time consuming and may not be easily handled
by untrained mechanics.
Although it may also be possible to utilize a computer in processing
the information, such a system is extremely complex and prohibitively
expensive, especially for small fluid systems. In any event, the
previously known flow rate meters do not provide a visual indication
of the tempertaure and flow rate in a manner which readily displays
other desired fluid flow characteristics, or in a manner which would
be readily understood by unskilled technicians and others without
substantial data processing.
SUMMARY OF THE PRESENT INVENTION
The present invention overcomes the above mentioned disadvantages
by providing a flow meter which provides an indication of the flow
rate by permitting direct observation of a displaceable member acted
upon by the flow of fluid. Generally, the flow meter comprises a
transparent housing portion adjacent a fluid passage in which a
displaceable indicator is acted upon by the flow stream through
the meter. The indicator includes a straignt line indicia, preferably
a radial edge on the indicator, to provide a visible indication
of the flow rate of fluid passing through the meter.
In the preferred embodiment of the present invention, the flow
meter housing is a tubular transparent housing portion in which
a displaceable flow rate indicator in the form of a piston is spring
biased toward one end of the housing. The indicator is linearly
displaceable along the tubular housing portion so that a linear
scale of flow rates can be exhibited by the flow meter. This can
be accomplished by tapering the inner peripheral wall at a predetermined
inclination from one end to the other, the degree of inclination
depending upon the range of flow rates to be indicated by the meter.
Moreover, the end of the tubular housing toward which the piston
is urged by the fluid includes an enlarged bore portion to form
a bypass for fluid when the flow rate of fluid exceeds a predetermined
value.
Also in the preferred embodiment, a temperature sensitive label
scaled to define a range of temperatures for the operating fluid
is aligned orthogonal to the flow rate scale. In addition, a chart
means having a graphic representation of a fluid characteristic
relating to flow rate and temperature can be superimposed upon or
aligned with the flow rate and temperature scales so that a relevant
value for an additional fluid characteristic is exhibited by the
meter without further analysis of fluid flow characteristics.
An advantageous use of a flow meter constructed in accordance with
the present invention includes the use of two flow meters secured
in the fluid system at predetermined points to determine the heat
flow rate, and thus the relative gain or loss of heat between those
points of the system. In such a case, the graphic representation
on the chart means includes indicia corresponding to the heat flow
rate at a particular fluid flow rate and temperature of the fluid.
By comparing the indications provided by each of the meters, the
difference in heat flow rates between the two points of the system
is relatively easy to understand from observation of the chart means
on each indicator. An alternative advantageous use of a flow meter
in accordance with the present invention permits the viscosity of
the fluid to be determined from observation of the chart means.
Thus, the present invention provides a flow meter wherein a visible
indicator is directly acted upon by the fluid flowing through the
meter. Thus, the present invention minimizes the complexity and
bulk of the flow meter structure and provides a highly efficient
indication of flow rate. In addition, the present invention provides
a means for utilizing sensed characteristics of the fluid to exhibit
the condition of the third characteristic related to two sensed
characteristics. In addition, the indication exhibited is readily
understood by unskilled or untrained personnel, and does not require
mental or computerized analysis of fluid characteristics exhibited
by the flow meter. These and other advantages will be more clearly
understood from the following discussion of the preferred embodiment
of the present invention.
BRIEF DESCRIPTION OF THE DRAWING
The present invention will be more clearly understood by reference
to the following detailed description of a preferred embodiment
of the present invention when read in conjunction with the accompanying
drawing, in which like reference characters refer to like parts
throughout the views and in which:
FIG. 1 is a front plan view of the flow meter constructed in accordance
with the present invention;
FIG. 2 is a rotated cross-sectional view taken substantially along
line 2--2 in FIG. 1;
FIG. 3 is a front view of a portion of the apparatus shown in FIG.
1;
FIG. 4 is a sectional view taken substantially along the line 4--4
in FIG. 2;
FIG. 5 is a sectional view taken substantially along line 5--5
in FIG. 2;
FIG. 6 is a sectional view taken substantially along the line 6--6
in FIG. 2;
FIG. 7 is a diagrammatic view of a fluid system employing a pair
of flow meters constructed in accordance with the present invention
and showing a modification thereof; and
FIG. 8 is an enlarged front view of a portion of the flow meter
shown in FIG. 7.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION
Referring first to FIG. 1 a flow meter 10 according to the preent
invention is thereshown connected in fluid communication with a
fluid system 12. The flow meter housing 11 includes a tubula, transparent
body portion 16 through which a displaceable indicator element 18
can be viewed. As will be described in greater detail hereinafter,
as fluid from the system 12 flows into the inlet 20 of the meter
10 the indicator 18 is displaced within the body portio 16 to provide
anindication of the flow rate of fluid through the meter 10. Flow
meter 10 may be provided with flow rate scale indicia 26 so that
the indicator edge 19 on the indicator 18 identifies a particular
flow rae value at the viewing face 21 of the body portion 16. Of
course, the fluid flows back into the system 12 from the meter 10
through the outlet 24.
As best shown in FIG. 2 the inlet 20 is formed by a threaded end
cap 30 which closes an open end of the housing portion 16. A fluid
passageway 32 in the end cap 30 is adapted to received a fluid coupling
for connecting the meter 10 in fluid communication with the system
12 in a well known manner. The tubular housing 16 includes a partition
or wall 34 in the form of a radial spider wall (FIG. 5) which supports
an elongated guide rod 36 extending axially through a chamber 38
formed by the tubular housing 16. The rod can be secured in the
wall by embedding, welding or other fastening means. The innermost
end of the cap 30 is spaced apart from wall 34 to form a chamber
35 therebetween in communication with the fluid passageway 32 and
the openings in wall 34. The end cap 30 is sealed to the end of
the tubular housing 16 by an "O" ring 48.
The other end of guide rod 36 is secured within a support body
40 which, as best shown in FIG. 6 has a spiderlike shape. The support
body 40 is retained in position adjacent an end cap 42 threadably
engaging the tubular end of the housing portion 16 and having a
fluid passageway 44 extending therethrough. The end cap 42 is spaced
slightly from the support body 40 to form a chamber 45 intermediate
passageway 44 and the openings in support body 40. The passageway
44 is adapted to receive a fluid coupling in a well known manner
to form the outlet 24. End cap 42 is fluidly sealed against the
housing portion 16 by an "O" ring 46.
The indicator element 18 includes a bore dimensioned to permit
the element 18 to slide along guide rod 36. The indicator 18 comprises
a substantially cylindrical body having a radially expanded indicator
edge 19. When the end of the indicator 18 abuts against the wall
34 the indicator edge 19 abuts against the inner periphery of the
tubular housing 16 and defines a zero-point for the flow rate scale.
At least a portion of the inner peripheral wall of the housing portion
16 such as portion 17 opposite viewing face 21 tapers radially
outwardly from the wall 34 towards the support body 40 so that displacement
of the indicator element 18 along the guide rod 36 causes at least
a portion of the indicator edge 19 to become spaced apart from the
inner periphery of the tubular housing 16 and permit passage of
fluid toward to outlet 24. Nevertheless, in the preferred embodiment,
a portion of the indicator edge 19 abuts against the viewing face
portion 21 of the housing and remains visible through the transparent
housing 16. In addition, the peripheral wall at the end 39 of chamber
38 includes an enlarged radial recess 90. Once the indicator 18
is urged into end 39 of chamber 38 when the flow rate exceeds the
normal range of the meter, fluid can freely pass beyond the indicator
18 and flow toward support body 40.
A spring 50 extends between support body 40 and the indicator 18
thus, normally retaining the indicator 18 in position against the
end wall 34. The coil spring 50 fits over a stub 80 of indicator
18 and a stub end 82 on support body 40. The outermost portions
of the stub ends 80 and 82 are tapered as shown at 84 and 86 respectively,
so that loops of the coil spring 50 can freely slide over the body
of the stub ends 80 and 82 without interference during compression
of the spring 50.
It is to be understood that fluid introduced into the inlet 20
passes through passageway 32 in the end cap 30 through chamber
35 through the apertures defined in the wall 34 and against the
indicator element 18 within the chamber 38. The indicator element
18 is thereby forced toward the outler 24 (to the left as shown
in FIG. 2) against the force of the spring 50. The taper of the
inner periphery of the wall forming the tubular housing 16 is determined
in accordance with the flow rate range to be indicated on the face
of the meter 10 so that displacement of the indicator 18 corresponds
to predetermined flow rates indicated on the flow rate indicia 26.
Moreover, the zero-point of the flow rate indicia 26 is aligned
with the position of indicator edge 19 when the indicator 18 is
at rest against wall 34.
Referring again to FIG. 1 the flow meter 10 according to the present
invention is well adapted for use with a temperture sensitive label
or strip 52 positoned below the zero-point indicated by the initial
position of the indicator edge 19. Heat contained in the fluid passing
through the system 12 is conducted to the strip 52 which is adhesively
secured to the exterior of the transparent housing portion 16. Although
the temperture sensitive strip 52 can be constructed in any known
manner, it is preferable that the strip 52 include scaled gradations
and numerical indicia to designate particular temperature ranges
within which the strip 52 is effective. In any event, the strip
52 preferably includes a heat sensitive material which changes color
as the temperature reaches a predetermined level, and the color
changes gradually along the length of the strip 52 as the temperature
increases to provide a discrete indication of temperature. In the
preferred embodiment, the strip 52 includes discrete crystal segments,
each of which changes color at a predetermined, progressively higher
temperature along the length of the strip 52.
As also shown in FIGS. 1 and 3 a chart means 56 for presentation
of an additional fluid characteristic can be applied over the transparent
body 16. The chart means 56 comprises a substantially transparent
panel 57 having a graphic representation of a particular fluid characteristic,
and is secured to the transparent housing portion 16 above the temperature
sensitive strip 52. The chart means 56 includes an orthoganal, ordinate
axis 60 corresponding to the flow rate indicia 26 and an abscissa
axis 62 corresponding to the termpeature indicia displayed on the
temperature sensitve strip 52. The alignment of the axes with the
zero point of indicia 26 and corresponding temperature indicia on
strip 52 enables the color line (shown in phantom line at 53 in
FIG. 3) exhibited by the strip 52 to be projected upwardly to intersect
with the indicator edge 19 of the indicator 18 whereby a particular
value of the characteristic indicated on the chart means 56 is visually
emphasized.
Still referring to FIG. 3 a particular chart means 56 is thereshown
including graphic representations of the viscosity of a fluid at
particular flow rates and temperatures in the form of curves 58.
The graph displays five discrete values of viscosity and the manner
in which such viscosity values are affected by temperature, as well
as the flow rate which will occur at a predetermined viscosity and
temperature. Thus, it will be understood that as the indicator edge
19 reflects the flow rate of the fluid flowing through the meter
10 and the colored portion of the strip 52 illustrates temperature
(as shown by the shading lines in FIG. 3), the projected intersection
of these indications identifies a particular point on the curves
58 so as to provide a readily perceptable indication of the viscosity
of the fluid flow through the system. Of course, it will be understood
that the range of values along the ordinate axis 60 and the range
of values indicated along the abscissa axis 62 are selected to correspond
and register with the flow rate values defined on the indicia 26
and temperature scale defined on the label 52 respectively, so
as to provide a direct correlation between the flow rate, temperature
and viscosity or other characteristic value displayed on the chart
means 56. Moreover, it will be understood that curves 58 can be
representative of other parameters specifically related to the particular
fluid flowing through the system 12.
An especially advantageous use of a flow meter constructed in accordance
with the present invention and some preferred modifications thereof
are shown in FIGS. 7 and 8. FIG. 7 shows a portion of a fluid system
in which a flow meter 10 is secured on the upstream side of a system
portion 13 as well as a downstream side of the system portion 13.
In addition, chart means 56 has been replaced with a chart means
68 providing a graphic representation of heat flow rates for the
particular fluid in the system as affected by flow rate of the system
and the temperature of the fluid in the system.
As best shown in FIG. 8 chart means 68 comprises a panel having
graphic indicia 78 in the form of sets of numerical indicia exhibiting
discrete values at numerous positions throughout the panel. Another
novel feature of the panel of chart means 68 is that it incorporates
sections of temperature sensitive material so that an entire section
will graphically display a color change in response to the change
in the temperature of the fluid. Thus, an entire column 72 is colored
in response to temperature so that the coloration projects upwardly
to intersect with the indicator edge 19 to permit observation of
the heat flow rate at the particular point in the system. Accordingly
in the system connected as shown in FIG. 7 a change in heat flow
rate occuring through the system portion 13 can be readily detected
by observing the difference in readings exhibited by the meters
10 connected on opposite sides of the system section 13.
Having thus described my invention, many modifications thereto
will become apparent to those skilled in the art to which it pertains
without departing from the scope and spirit of the present invention
as defined in the appended claims.
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