Abstrict An arrangement for testing a flow meter which issues a first train
of pulses in response to the rotation of a rotatable member thereof
includes a measuring cylinder-and-piston unit that has a cylinder,
a piston slidably received in the cylinder and displacing a known
comparison volume of a fluid out of the cylinder for delivery to
the flow meter, and a piston rod which extends to the exterior of
the cylinder. A photoelectric sensing arrangement is mounted on
the piston rod for joint movement therewith along a stationary volume
scale to scan distancing markings of such scale and issue a second
train of pulses in response to the detection thereof. A first of
such distancing markings is so situated that the sensing arrangement
encounters the same only after the piston rod has covered an initial
distance corresponding to a running-in distance of the piston. A
lug with countermarkings corresponding to the distancing markings
is mounted on the piston rod and interposed in the light path of
the photoelectric sensing arrangement to mask and unmask the distancing
markings and thus to achieve a pronounced light-dark effect. The
first pulse of the second pulse train triggers the counting of the
pulses of the first pulse train which are correlated to the number
of revolutions of the rotatable member of the flow meter, and a
correction is made after the termination of a test run for pulse
fractions occurring at the beginning and at the end of the testing
run.
Claims What is claimed as new and desired to be protected by Letters Patent
is set forth in the appended claims.
1. An arrangement for testing a flow meter having at least one
rotatable member and issuing a first train of electrical pulses
proportionally to the extent of rotation of the rotatable member,
comprising a measuring cylinder-and-piston unit including a cylinder,
a piston slidably received in said cylinder and operative for displacing
a fluid out of the latter, and a piston rod rigid with said piston
and extending to the exterior of said cylinder, said unit being
connected to the flow meter during testing to deliver the displaced
fluid to the flow meter; means for correlating the number of pulses
of the first train during a testing run to the number of complete
revolutions of the rotatable member of the flow meter; means for
generating a second train of electrical pulses proportionally to
the extent of movement of said piston rod, including a stationary
volume scale extending parallel and proximate to said piston rod
and having a multitude of equidistant distancing markings, and sensing
means mounted on said piston rod for joint movement therewith and
operative for scanning said distancing markings and issuing the
pulses of the second train in response to the detection thereof,
said distancing markings being so arranged on said volume scale
that said sensor encounters a first one thereof only after said
piston rod has moved from its rest position through a predetermined
initial distance; and means for utilizing the pulse of said second
train that corresponds to said first distancing marking for triggering
said correlating means.
2. The arrangement as defined in claim 1 and further comprising
computing means including data storage means storing the known number
of the pulses of the first pulse train per revolution of the rotatable
member of the respective flow meter to be tested, means for storing
the number of the pulses of the first pulse train that occur during
the entire stroke of the piston in the course of a pre-testing run,
and means for calculating from said stored number and from said
known number the number of complete revolutions of the rotatable
member of the flow meter and thus the number of the pulses of the
first pulse train occurring during said testing run.
3. The arrangement as defined in claim 1 wherein said distancing
markings include alternating opaque bars and transparent gaps of
substantially the same widths; wherein said sensing means includes
a light source which illuminates said bars and gaps and a photoelectric
sensor which detects the influence of said bars and gaps on the
light issued by said light source; and further comprising a masking
lug mounted on said piston rod for joint movement therewith, interposed
between said light source and said sensor and including a smaller
number of countermarkings corresponding to said distancing markings
and presenting, in cooperation with said distancing markings, a
light or dark signal for said photosensitive sensor.
4. An arrangement for testing a flow meter having at least one
rotatable member and issuing a first train of electrical pulses
proportionally to the extent of rotation of the rotatable member,
comprising a measuring cylinder-and-piston unit including a cylinder,
a piston slidably received in said cylinder and operative for displacing
a fluid out of the latter, and a piston rod rigid with said piston
and extending to the exterior of said cylinder, said unit being
connected to the flow meter during testing to deliver the displaced
fluid to the flow meter; means for correlating the number of pulses
of the first train during a testing run to the number of complete
revolutions of the rotatable member of the flow meter; means for
generating a second train of electrical pulses proportionally to
the extent of movement of said piston rod, including a stationary
volume scale extending parallel and proximate to said piston rod
and having a multitude of equidistant distancing markings, and sensing
means mounted on said piston rod for joint movement therewith and
operative for scanning said distancing markings and issuing the
pulses of the second train in response to the detection thereof,
said distancing markings being so arranged on said volume scale
that said sensor encounters a first one thereof only after said
piston rod has moved from its rest position through a predetermined
initial distance; means for utilizing the pulse of said second train
that corresponds to said first distancing marking for triggering
said correlating means; and further comprising a clock issuing a
train of clocking oscillations, first counting means for counting
the number of oscillations Tm occurring during a time period elapsing
between a first and a last of said pulses of said first pulse train,
second counting means for counting the number of oscillations Tp
occurring during a time period elapsing between the first and last
pulses of said second pulse train which respectively follow said
first and last pulses of said first pulse train; means for setting
said numbers of oscillations Tm and Tp in a ratio; and means for
deriving a number q of pulses of the first pulse train that is corrected
for pulse fractions occurring in the second pulse train during the
testing run by multiplying said ratio with a number m of the pulses
of the second pulse train in accordance with the equation ##EQU11##
5. The arrangement as defined in claim 4 and further comprising
means for utilizing, with a non-integral total pulse number r for
the testing run, the pulse of the second pulse train that follows
this total number r as a stop pulse which terminates the counting
of said pulses of said second train.
Description BACKGROUND OF THE INVENTION
The present invention relates to testing arrangements in general,
and more particularly to an arrangement for testing a flow meter.
There are already known various constructions of flow meters, among
them such which are incorporated into a pipeline and include rotating
measuring wheels or similar rotating measuring members. For testing
or calibrating such flow meters, there is often used, in series
with the flow meter, a measuring or reference cylinder-and-piston
unit which includes a housing or cylinder, in the interior of which
there is slidably received a floating measuring piston which is
displaced by the fluid being measured and which determines a comparison
volume displaced out of the cylinder-and-piston unit between a start
position and a stop position of the piston, such comparison volume
being supplied to the flow meter. Typically, a piston rod is rigidly
connected the the floating measuring piston and extends to the exterior
of the cylinder. Usually, the duration of a testing operation, which
takes place between the start position and the stop position, is
determined by a predetermined number of first electrical pulses
which are issued by the flow meter being tested. Then, a start pulse
originating at the flow meter and issued after the end of the initial
running-in displacement of the measuring piston triggers the counting
or summation of a train of second electrical pulses which are issued
by a pulse generator that responds to the movement of the piston
rod. This counting or summation is then discontinued at the end
of the testing run by the last pulse issued by the flow meter. The
comparison parison volume which results from the counting or summation
of the second pulses of the second pulse train is then compared
with the volume which results from the first pulses of the first
pulse train.
A testing arrangement of this type is known, for instance, from
the U.S. Pat. No. 3492856. In this arrangement, the outwardly
extending piston rod of the measuring piston is connected by means
of a cross-beam rigidly with a toothed rack that is guided in sliding
guides for movement parallel to the piston rod. This toothed rack
then transfers the movements of the piston rod through a plurality
of transmission gears to a shaft which is connected with a pulse
generator. This pulse generator issues, in dependence on the rotational
angular position of the shaft, a large number of electrical pulses.
What is disadvantageous in this known testing arrangement is that,
due to the rigid connection of the toothed rack with the piston
rod, the second pulse train is already commenced to be issued at
the very beginning of the movement of the measuring piston, even
though the measuring piston has not yet covered or been displaced
by the initial or running-in distance which is needed for the quieting
or smoothing of the flow prior to the start of the testing run proper.
This problem has already been recognized and, in order to take
this initial running-in distance of the measuring piston into account,
it was proposed in one known testing arrangement to incorporate
a time-delay member into the electric circuitry. This time-delay
member inhibits the summation or counting of the pulses of the second
pulse train, commencing with the first pulse issued by the pulse
generator, until the end of its time-delay period. Then, the first
pulse issued by the flow meter after the expiration of such time-delay
period triggers, in its capacity as a starting pulse, the summation
or counting of the pulses of the second pulse train. Herein, the
initial running-in distance of the measuring piston until the beginning
of the testing run proper is determined by the time-delay member,
so that different initial running-in distances occur at different
flow velocities. As a result of this, the amount of the fluid in
the comparison volume that is available for the testing run may
be too small at high fluid flow velocities.
In these testing arrangements, which have become known under the
name "Miniprover", the dimensions of the measuring cylinder-and-piston
units have been held so small that the entire testing arrangement
can be mounted on a normal motor vehicle trailer. Under these circumstances,
the comparison volume displaced from the measuring cylinder-and-piston
unit by the measuring piston between its start and stop positions
is nowadays so small that the measuring wheels of the flow meter
being tested conduct only a few revolutions during the testing run.
Typically, the volume of the fluid displaced by the measuring piston
in such "Miniprovers" lies between 8 and 200 liters, depending
on the size of the testing equipment. So, for example, the comparison
volume is indicated to be about two gallons, that is, about 8 liters,
in the U.S. Pat. No. 3492856. This means that the unavoidable
tolerances in the shapes of the gear teeth, or an elastic deformation
in the bulky scanning construction consisting of the piston rod,
cross-beam and toothed rack, or even a minute irregularity in the
issuance of the flow meter signals, have already marked deleterious
influence on the accuracy of the measurement, resulting in substantial
measurement errors. Experience has shown that the known "Miniprovers"
tend to too great a scatter of the measurement results, because
of the only small number of the pulses issued by the flow meter
during the test run, the measurement results differing in dependence
on the construction of the flow meter being tested.
SUMMARY OF THE INVENTION
Accordingly, it is a general object of the present invention to
avoid the disadvantages of the prior art.
More particularly, it is an object of the present invention so
to construct the arrangement of the type here under consideration
as not to possess the disadvantages of the known constructions of
this type.
Still another object of the present invention is so to design the
arrangement of the above type as to achieve an improved accuracy
of measurement independently of the construction of the flow meter
being tested.
It is yet another object of the present invention to devise a testing
arrangement of the above type which is relatively simple in construction,
inexpensive to manufacture, easy to use, and reliable in operation.
In pursuance of these objects and others which will become apparent
hereafter, one feature of the present invention resides in an arrangement
for testing a flow meter having at least one rotatable member and
issuing a first train of electrical pulses proportionally to the
extent of rotation of the rotatable member, which arrangement comprises
a measuring cylinder-and-piston unit including a cylinder, a piston
slidably received in the cylinder and operative for displacing a
fluid out of the latter, and a piston rod rigid with the piston
and extending to the exterior of the cylinder, this unit being connected
to the flow meter during testing to deliver the displaced fluid
to the flow meter; means for correlating the number of pulses of
the first train during a testing run to the number of complete revolutions
of the rotatable member of the flow meter; means for generating
a second train of electrical pulses proportionally to the extent
of movement of the piston rod, including a stationary volume scale
extending parallel and proximate to the piston rod and having a
multitude of equidistant distancing markings; and sensing means
mounted on the piston rod for joint movement therewith and operative
for scanning the distancing markings and issuing the pulses of the
second train in response to the detection thereof, the distancing
markings being so arranged on the volume scale that the sensing
means encounters a first one thereof only after the piston rod has
moved from its rest position through a predetermined initial distance;
and means for utilizing the pulse of the second train that corresponds
to the first distancing marking for triggering the correlating means.
The present invention is based on the recognition of the fact that
the spreading or scattering of the measuring results is primarily
caused by irregular, that is, not volume-proportional, pulse issuance.
Thus, it was discovered that, even in turbine counters, even the
distribution error in the blades of the turbine wheel which is customary
and acceptable in the industry, is sufficient to cause a no longer
acceptable measuring result scattering during the use of a "Miniprover"
as the testing arrangement. The scattering effect is even more pronounced
in conjunction with oval gear flow meters, inasmuch as, even here,
the issuence of the pulses during each revolution is not proportional
to the volume, in that the transmission ratio of such oval gears
constantly changes and even the fluid volume varies depending on
the angular position.
As a result of the fact that, according to the present invention,
the number of the pulses issued by the flow meter between the start
and the termination of the testing run is coordinated or correlated
to the number of revolutions of the rotatable member or measuring
wheel of the flow meter, the position of such measuring wheels is
identical at the beginning and at the end of the testing run, so
that all irregularities which occur periodically with the rotation
of the measuring wheel are securely eliminated. This is also valid
for oscillations which are caused by the magnetic couplings built
into the flow meter and attributable to the irregular operation,
since such oscillations recur with the period of complete measuring
wheel revolutions. The sensor which generates the second pulse train
is mounted directly at the end of the piston rod and scans during
the movement of the measuring piston the non-loaded and stationary
volume scale that is provided with the distancing markings. In this
manner, there are eliminated even those measuring errors which are
otherwise attributable to the elastic deformation and/or manufacturing
tolerance caused distribution errors of the scanning structure.
The scanning of the volume scale is accomplished in a non-contacting
fashion, that is, with the avoidance of any friction and practically
without delay and in a force-free manner, and the distancing marks
can be provided on the volume scale at very precise distancing with
respect to one another.
Inasmuch as the distancing markings only commence at the end of
the initial running-in distance of the measuring piston, the same
part of the measuring cylinder is available for the running-in of
the measuring piston under all circumstances, that is, regardless
of the flow velocity, so that the measurement also commences in
all cases at the same position of the measuring piston and the remaining
part of the stroke of the measuring piston, and thus the remaining
volume of the fluid in the measuring cylinder, is always available
for the conduct of the testing run and for the determination of
the integral or complete revolution number of the measuring wheel
of the flow meter during the test run proper. The first signal or
pulse issued by the sensor of the piston rod is herein used directly
as the triggering signal for the beginning of the counting of the
pulse train, so that time-delay members are no longer necessary.
According to another aspect of the invention, the testing arrangement
further comprises a clock issuing a train of clocking oscillations,
first counting means for counting the number of oscillations Tm
occurring during a time period elapsing between a first and a last
of the pulses of the first pulse train, second counting means for
counting the number of oscillations Tp occurring during a time period
elapsing between the first and last pulses of the second pulse train
which respectively follow the first and last pulses of the first
pulse train, means for setting the numbers of oscillations Tm and
Tp in a ratio, and means for deriving a number q of pulses of the
first pulse train that is corrected for pulse fractions occurring
in the second pulse train during the testing run, by multiplying
the ratio with a number of pulses m of the second pulse train during
the testing run. As a result of this correction, there are captured
even the pulse fractions occurring during the testing run between
the start and stop. In this manner, the measuring accuracy is further
enhanced.
In those instances where a transmission with a non-integral transmission
ratio is interposed between the measuring wheel and the pulse generator
of the flow meter, it can happen that an integral multiple of the
measuring wheel revolutions results in a non-integral number of
pulses issued by the pulse generator of the flow meter. In order
to avoid the measuring error attributable to such non-integral number
of pulses, it is proposed by the present invention to perform a
time correction to the next complete pulse. In this connection,
it was recognized that, in conjunction with the above-mentioned
correction, it is possible simultaneously to take the pulse fractions
of the first and second pulse trains into consideration.
According to another facet of the present invention, it is possible
to determine the number of pulses issued by the flow meter during
the test run so as to be correlated to the number of complete revolutions
of the measuring wheel of the flow meter by providing computing
means which includes data storage means that stores to known number
of the pulses of the first pulse train per revolution of the measuring
wheel or a similar rotatable member of the flow meter to be tested,
means for storing the number of pulses of the first pulse train
that occurs during an entire stroke of the piston on the course
of a pre-testing run, and means for calculating from the stored
number and from the known number the number of complete revolutions
of the rotatable member of the flow meter and thus the number of
pulses of the first pulse train occurring during the testing run.
It is further advantageous when, in accordance with the present
invention, the distancing markings include alternating bars and
gaps of substantially the same widths, when the sensing means includes
a light source which illuminates the bars and gaps and a photoelectric
sensor which detects the influence of the bars and gaps on the light
issued by the light source, and when there is further provided a
masking lug also mounted on the piston rod for joint movement therewith,
interposed between the light source and the sensor, and including
a smaller number of countermarkings corresponding to said distancing
markings and presenting, in cooperation with said distancing markings,
a light-dark effect for the photosensitive sensor. In this manner,
there is obtained for the photosensitive diode of other sensor during
the movement of the piston rod a light-dark contrast effect which
stretches over a greater area and thus can be more easily detected
by the sensor. This effect is caused by the juxtaposition of the
bars of the lug with either the bars or the gaps of the volume scale,
with attendand covering and uncovering of the gaps. Advantageously,
the volume scale and the masking lug are made of a transparent material
and the light source and sensor are arranged across such lug and
scale from one another, so that the light penetrates through the
gaps between the respective bars of the lug and scale.
The novel features which are considered as characteristic of the
invention are set forth in particular in the appended claims. The
improved testing arrangement itself, however, both as to its construction
and its mode of operation, together with additional features and
advantages thereof, will be best understood upon perusal of the
following detailed description of certain specific embodiments with
reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a diagrammatic represention showing the association of
pulses of a first train originating at a flow meter with pulses
of a second pulse train originating at a piston rod of a measuring
cylinder-and-piston unit;
FIG. 2 is a somewhat diagrammatic side elevational view showing
the cooperation of the piston rod with a stationary volume scale
of the arrangement of the present invention; and
FIG. 3 is an end elevational view of the arrangement depicted in
FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawing in detail, and first to FIG. 1 thereof,
it may be seen that in this diagrammatic representation a first
pulse train 4 which is generated in dependence on the operation
of a flow meter being tested is shown at the lower region, while
a second pulse train 5 which has originated at a measuring cylinder-and-piston
unit is depicted at the upper region. As may be ascertained from
FIGS. 2 and 3 the second pulse train 5 is issued by a sensor 8
which is mounted at an end 6 of a piston rod 7 of the above-mentioned
measuring cylinder-and-piston unit. Both the flow meter being tested
and the measuring cylinder-and-piston unit are of conventional construction,
so that they need not, nor will they, be discussed here in any greater
detail than necessary for understanding the present invention. Suffice
it to say that the flow meter being measured includes at least one
rotatable member, which will be referred to here as a rotatable
measuring wheel even though it may be in fact a gear or other rotatable
member and which is caused to rotate by the flow of a fluid through
the flow meter at a speed proportionate to the amount of flow of
the fluid through the flow meter, and that the measuring cylinder-and-piston
unit includes a cylinder, a piston slidably received in the interior
of the cylinder, and a piston rod that extends to the exterior of
the cylinder, the piston displacing a known amount of the fluid
per unit of time out of the interior of the cylinder and through
suitable conduit means into the flow meter. In FIG. 2 only a portion
of the cylinder and the portion of the piston rod 7 that extends
to the exterior of the cylinder of the measuring cylinder-and-piston
unit is shown.
In the construction illustrated in FIGS. 2 and 3 the sensor 8
is constructed as a photosensitive diode and light emitted by a
light source 9 is aimed at the same. The photosensitive diode 8
and the light source 9 are supported on the legs of a U-shaped carrier
which is rigidly connected with the piston rod 7. During the testing
operation, the photosensitive diode 8 optoelectrically scans equidistant
distancing markings 11 of a stationary volume ruler 12 and issues
during and in response to each passage of a distancing marking 11
an electrical signal or pulse 13 (see FIG. 1) of the second pulse
train.
The volume ruler 12 has such a length that the distancing markings
11 provided thereon extend over a distance that corresponds to the
entire useful stroke of the measuring piston or of the piston rod
7 which shares in the movement of the measuring piston so that the
distance through which the piston rod 7 travels is an accurate indication
of the volume of the fluid displaced by the piston of the measuring
cylinder-and-piston unit and delivered to the flow meter being tested,
for instance, for calibration purposes. The total number of the
distancing markings 11 provided on the volume ruler or scale 12
is selected, by resorting to fine division, as large as possible,
in order to obtain high resolution for the known reference volume
displaced by the measuring piston of the measuring cylinder-and-piston
unit.
FIG. 2 shows the piston rod 7 in its position assumed at the beginning
of the testing operation. A first of the distancing markings 11
which is identified by the reference numeral 14 for differentiation
purposes, provided on the volume scale 12 is provided only at the
end of an initial displacement distance of the piston rod 7 which
is denoted by the reference numeral 15. This initial displacement
distance 15 is covered by the piston rod 7 while the measuring piston
conducts its initial movement out of its end position and the flow
of the fluid displaced by the measuring piston has not yet quieted
down to its steady state. During the passage of the sensor 8 past
this initial distancing marking 14 the photosensitive diode 8 issues
an initial or starting signal 16 (see FIG. 1) for the second pulse
train 5 which now triggers the start of the testing run at the
occurrence of the next following pulse 17 of the first pulse train
4 at a starting time 18. Commencing with a second pulse 19 of the
second pulse train 5 occurring at or after the starting time 18
pulses 13 of the second pulse train 5 are now counted or summated.
The number of pulses 20 of the first pulse train 4 issued by the
flow meter during the testing run is accomodated to the greatest
possible multiple of the pulse number per measuring wheel revolution,
so that a stop pulse 21 is issued by the flow meter being tested
at the end of the last full measuring wheel revolution, which triggers
a stop 22 of the testing run. As a result of this, the counting
or summation of the pulses 13 of the second pulse train 5 originating
at the sensor 8 of the piston rod 7 is discontinued at the occurrence
of a next following pulse 23 of the second pulse train 5 after the
stop 22. While the first pulse train 4 originating at the flow meter
begins during the testing run with the rising flank of the first
pulse 17 at the starting time 18 and ends with the rising flank
of the last pulse 21 of the first pulse train 4 at the stop time
22 in the illustrated situation a time delay at the starting time
18 corresponding to a pulse duration fraction 24 occurs in the second
pulse train 5 originating at the sensor 8 prior to the occurrence
of the first pulse 19 and another time delay corresponding to a
pulse duration fraction 25 is encountered at the stop 22 prior to
the last pulse 23 of the second pulse train 5.
The distancing markings 11 of the volume scale or ruler 12 are
constituted by opaque lines 27 and intervening transparent gaps
28 which are both of the same width. A masking lug 29 is arranged
in front of the photodiode or sensor 8 the lug 29 being mounted
on a carrier 10 which is mounted on the end portion 6 of the piston
rod 7 together with the sensor 8 and the light source 9. This lug
29 is provided with countermarkings 30 corresponding to lines 27
and gaps 28 of the distancing markings 11 on the volume ruler 12
but being reduced in number. The volume ruler or scale 12 and the
lug 29 are both made of a transparent material, so that a pronounced
light or dark signal is alternatively received by the photosensitive
diode or sensor 8 during the passage of the markings 30 on lug 29
past the markings 11 of the volume scale 12 due to the masking and
unmasking of the transparent gaps 28 of the volume ruler 12 by the
opaque lines of the markings 30 on lug 29.
In order to compensate for the pulse fractions 24 and 25 caused
by the time delays at the starting time 18 and at the stop 22 in
the pulses 13 of the second pulse train 5 originating at the sensor
8 or to take them into account, a timing quartz clock is provided
which oscillates during the testing run. This timing quartz clock,
which is of a conventional construction and thus has not been shown
in the drawing, measures and records a time period Tm elapsing between
the first pulse 17 and the last pulse 21 of the first pulse train
4 on the one hand, and a time perion Tp elapsing between the first
pulse 19 and the last pulse 23 of the second pulse train 5 occurring
during the testing run. If now m is used to indicate the number
of the summated or counted pulses during the time period Tp and
q the total amount of pulses changed by the pulse fractions 24 and
25 then the following equation applies
From this, there is obtained the corrected total pulse amount
Thus, for taking the pulse fractions 24 and 25 into account, it
is merely necessary to multiply the ratio of Tm:Tp by the number
m of the summated or counted pulses 13. The multiplication is accomplished
in a computer of the testing equipment.
A scaling factor k.sub.m for the flow meter results from a total
number n of the pulses 20 of the first pulse train issued during
the testing run per a unit of volume V (selected for the testing
equipment) from the equation ##EQU3## Correspondingly, a k.sub.p
value of the testing equipment is obtained from the equation ##EQU4##
Now, if the two units of volume V are considered to be identical,
there is obtained the equation ##EQU5##
If the previously mentioned equation is substituted for q in the
above equation, the result is
If a non-integral total pulse number r results for a testing run
that takes place during a time period Tm2 when the pulse number
per measuring wheel revolution of the flow meter is not integral,
the pulse 21 which follows this non-integral pulse number r is utilized
as stop pulse for the second pulse train 5 so that the calculation
starts from an integral number n. Here, the following equations
apply: ##EQU7## Furthermore, the following is valid for the k values:
##EQU8## After the setting of V equal, the following obtains: ##EQU9##
Now, if r and q are isolated from the previous equations and substituted
into the above equations, what is obtained is: ##EQU10##
The recognition from this is that the correction of the first pulse
train 4 can be accomplished independently of Tm2 and results solely
from the multiplication with the ratio Tp:Tm simulataneously with
the correction for the pulse fragments 24 and 25 of the second pulse
train 5 issued by the sensor 8 of the piston rod 7.
It will be understood that each of the elements described above,
or two or more together, may also find a useful application in other
types of arrangements differing from the type described above.
While the invention has been illustrated and described as embodied
in a testing arrangement for a flow meter, it is not intended to
be limited to the details shown, since various modifications and
structural changes may be made without departing in any way from
the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the
gist of the present invention that others can, by applying current
knowledge, readily adapt it for various applications without omitting
features which, from the standpoint of prior art, fairly constitute
essential characteristics of the generic and specific aspects of
my contribution to the art and, therefore, such adaptations should
and are intended to be comprehended within the meaning and range
of equivalence of the claims. |