Abstrict A flow meter for metering the flow of gaseous or liquid media comprising
a rotatably movable measuring organ, a measured-value pickup device
for obtaining an electrical quantity corresponding to the revolutions
of the measuring organ, and an evaluating device connected to the
measured-value pickup device. In accordance with the invention,
the flow meter is further provided with a voltage generator responsive
to the measuring organ and with a means for coupling the output
voltage of the generator via an electrical buffer device to the
measured-value pickup device and/or the evaluating device.
Claims What is claimed is:
1. In a flow meter for metering the flow of a medium, said flow
meter comprising a chamber in which is disposed at least one rotatably
moveable measuring organ, a measured value pickup device for deriving
an electrical quantity corresponding to the revolutions of said
measuring organ, and an evaluating device responsive to the pickup
device, the improvement comprising:
(a) a voltage generator separate from said pickup device and connected
in driving relationship with said measuring organ, said generator
comprising a magnetic coupling responsive to said measuring organ
for providing an indication of the rotary movement of said measuring
organ and a winding arrangement disposed adjacent said magnetic
coupling providing an output voltage; and
(b) means responsive to the output voltage of said winding arrangement
for supplying power to one of said pickup device and said evaluating
device.
2. A flow meter in accordance with claim 1 wherein:
said magnetic coupling includes separated half portions;
and said winding arrangement is fixedly arranged between said half
portions.
3. A flow meter in accordance with claim 1 wherein:
said winding arrangement is a printed circuit.
4. A flow meter in accordance with claim 1 wherein:
said electrical evaluating device comprises:
an electronic counting chain including a number of connected electrical
building blocks; and a display device.
Description BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a volume measuring instrument or flow
meter for measuring the flow of gaseous or liquid media and, in
particular, to a flow meter having at least one rotatably movable
measuring organ, a measured-value pickup device responsive to the
measuring organ for obtaining an electrical quantity corresponding
to the revolutions of the organ, and an evaluating device connected
to the measured-value pickup device.
2. Background of the Invention
In one knwon flow meter of above type, the measured-value pickup
device comprises a reed relay mechanism with a revolving support
element driven by a rotatably movable measuring organ. This latter
support element carries a mangetically conductive ring and is moved
by the organ past the reed relay which is connected into a circuit
with a supply voltage source and a counter. When the reed relay
operates, both its contacts are closed and a current pulse flows
to the counter. This known flow meter, therefore, requires the use
of a separate supply voltage source, which may be formed, for example,
by a storage battery.
Also known is another flow meter comprising an electronic pulse
generator which contains a stationary coil. An a-c voltage is induced
in this coil by a ring magnet coupled to and moved by a rotatably
movable measuring organ included in the meter. This a-c voltage
is processed in an evaluating device which contains, besides a voltage
amplifier, a Schmitt trigger and an electronic counter. The aforesaid
evaluating device requires for the operation of its individual parts
a supply voltage, which is made available by a separate supply voltage
source.
Thus, in all the known flow meters which employ a measuring organ
and a measured-value pickup device responsive to the organ for deriving
an electrical quantity corresponding to the revolutions of the organ,
a separate supply voltage source is required. These meters thus
differ in this respect from flow meters in which the processing
of the picked-up measurement value and its evaluation are effected
by number wheels driven by the movable measuring organ in a mechanical
counting mechanism.
It is therefore an object of the present invention to provide a
flow meter of the above type which does not require a separate supply
voltage source.
SUMMARY OF THE INVENTION
In accordance with the principles of the present invention the
above and other objectives are accomplished in a flow meter of the
above type by further including therein a voltage generator responsive
to the rotatably movable measuring organ and means for connecting
the output voltage of the generator, to one of the measured-value
pickup device and the evaluating device of the meter for supplying
voltage to same. More particularly, the aforesaid generator is connected
in driving relationship with the measuring organ and the means for
connecting is provided with an electrical buffering device connected
between the generator and the pickup device or evaluating device.
With the flow meter designed as aforesaid, the measurement value
proper is derived from the flow energy of the gaseous or liquid
medium to be measured, as well as the energy which is required for
processing and displaying the measurement value. Analogous to purely
mechanical flow meters, the flow meter according to the invention
thus does not require an additional supply voltage source and is,
therefore, independent of external energy sources.
In the flow meter of the present invention, the measured-value
pickup device can be constructed in a number of different ways.
Thus, for example, it may be construction as an electric pulse generator
such as is described in the German Pat. No. 1298603. In such case,
the pickup device generates a voltage which produces a current pulse
for a counter when the contacts of the reed relay are operated.
However, the measured-value pickup device may also be constructed
as a tachometer generator, so that it will then be independent of
a supply voltage unit. For processing the voltage of the tachometer
generator, however, a supply voltage is then necessary which is
made available by the voltage generator of the flow meter.
The generator of the flow meter of the present invention can also
be constructed in a number of different ways. Thus, it is considered
advantageous to construct the generator as a separate structural
component which is driven by the rotatably movable measuring organ.
In such case, the output shaft of the rotatably movable measuring
organ can be extended to the generator through the measuring chamber
containing the organ.
In cases where the flow meter is desired to be as small as possible,
it is advantageous to form the generator from a magnet arrangement
carried by the measuring organ and from a winding arrangement fixedly
mounted in a housing containing the measuring organ. The respective
placement of the magnet arrangement with respect to the measuring
organ and also the placement of the winding arrangement in the housing
is determined in this case largely by the design of the flow meter
itself.
Flow meters are frequently equipped with a magnetic coupling in
order to transmit the rotary motions of the measuring organ through
the wall of the measuring chamber containing the measuring organ
to an indicating mechanism arranged outside the measuring chamber.
In a flow meter of such design modified in accordance with the invention,
it is advantageous to form the generator of the meter from the magnetic
coupling and from a winding which is arranged adjacent to the coupling.
For space reasons, it is considered particularly advantageous if
the winding is fixedly arranged in the space between the two half
portions of the magnetic coupling.
Such a design of the generator has the important advantage that
an additional magnet arrangement is not required for its formation.
Also the mounting of the winding presents no special problems in
this arrangment of the generator, as the winding, being designed
as flat as possible, can be fastened without difficulty to a partition
between the half portions of the magnet coupling. Advantageously,
a winding in the form of a printed circuit can be employed in the
aforesaid case.
The evaluating device of the flow meter of the invention may contain
an electronic counting chain and a display, the electronic counting
chain being formed advantageously by integrated electronic building
blocks in order to keep its energy requirements as low as possible.
For the same reason, it appears advantageous if the display device
contains liquid-crystal display elements of field-effect display
elements.
BRIEF DESCRIPTION OF THE DRAWING
The above and other features and aspects of the present invention
will become more apparent upon reading the following detailed description
in conjunction with the accompanying drawings, in which:
FIG. 1 shows a flow meter including a magnetic coupling and configured
in accordance with the principles of the present invention;
FIG. 2 illustrates a winding arrangement useable in the flow meter
of FIG. 2;
FIG. 3 shows in block diagram form, the generator of a flow meter
in accordance with the invention used for supplying power to the
measured-value pickup device of the meter;
FIG. 4 shows the generator of a flow meter in accordance with the
invention incorporated into a hand counter;
FIG. 5 shows in block diagram form the voltage generator of the
flow meter of FIG. 4;
FIGS. 6 and 7 show further flow meters in accordance with the principles
of the invention.
DETAILED DESCRIPTION
FIG. 1 shows a flow meter in accordance with the principles of
the present invention. To avoid overly complicating the drawings
only those portions of the meter relevant to the invention are illustrated.
The flow meter comprises a measuring chamber 1 in which is disposed
a rotatably movable measuring organ or member 2 which is in the
form of a turbine wheel. The measuring organ 2 is fastened on a
shaft 3 which is supported in a bearing at the region 4. Fastened
to the end of the shaft 3 facing away from the measuring organ 2
is a first half portion 5 of a magnetic coupling 6. The half portion
of 5 the magnetic coupling 6 comprises a support disk 7 on which,
for example, four magnets 8 are arranged around its circumference
in such a manner that the magnets of different polarity alternate.
The half portion 5 of the magnetic coupling 6 is separated by a
thin partition 9 of the measuring chamber 1 from the other half
portion 10 of the coupling 6 the half portion 10 likewise comprising
a support disk 11 around whose circumference are arranged four magnets
12 which alternate in polarity. The support disk 10 is fastened
on a shaft 13 which is supported in the partition 9. A further
bearing point for the shaft 13 is located in the cover 14 of a further
housing part 15 which is bolted to the measuring chamber 1.
The shaft 13 above the support disk 10 further supports a support
element 16 having a magnetically conducting ring 17 on which a
number of permanent magnets 18 and 19 are located. When the shaft
13 rotates, the magnetically conducting ring 17 and its associated
permanent magnets are moved thereby past a number of reed relays
20 and 21 the contacts 22 23 and 24 25 respectively, of which
are closed and opened by the permanent magnets alternatingly.
The contacts 22 23 and 24 25 are connected via lines 26 and 27
into the circuit comprising a supply voltage source and an electromechanical
counting mechanism, the latter element not being shown in FIG. 1.
Thus an electrical pulse which is counted in the counter is generated
upon each closing of the contacts 22 23 and 24 25 respectively.
The count in the counter is, therefore, proportional to the rotary
movement of the measuring organ 2 and hence, corresponds to the
amount of liquid or gas that has run through the measuring chamber
1.
Between the half portions 5 and 10 of the coupling 6 is located
a thin winding 28 which, together with the magnetic coupling 6
forms a generator. The ends 29 of the winding 28 extend out of the
cover and form the voltage output of the generator. The generator
together with a rectifier arrangement and a buffer device (not shown),
in turn, form the aforesaid supply voltage source for the electromechanical
counting mechanism. The flow meter of FIG. 1 therefore, requires
no additional external supply voltage for generating pulses.
FIG. 2 shows a top view of a winding which can be used for the
winding 28 of the flow meter of FIG. 1. The winding is in the form
of a printed circuit board 31 having the turns 30 situated in part
on different sides so that the conductors are supported as required.
The illustrated winding is particularly flat and can, therefore,
be accommodated at the partition 9 between the half portions 5 and
10 of the magnetic coupling 6 without interfering with the operation
of the coupling.
FIG. 3 shows a block diagram of the connection of the voltage generator
of FIG. 1 to its respective rectifier arrangement and buffer device
to form the voltage source for the electromechanical counting meachanism.
The generator is symbolically depicted by a source 33 whose output
voltage 32 is connected via a rectifier arrangement 34 to a buffer
device 35 which, for example, may be a buffer storage battery.
Connected to the buffer device 35 is a pulse generator, the pulses
of which can be transmitted via a connecting line 37 to a counting
device, not shown. The pulse generator 36 may, for example, take
the form of the pulse generator structure shown in FIG. 1.
The rectifier 34 can be disposed, together with the buffer device
35 in the housing 15 of the flow meter of FIG. 1. However, it is
also possible to mount the rectifier and the buffer storage device
in an additional housing, physically separated from the flow meter,
together with the display device.
FIG. 4 shows a flow meter in accordance with the invention, designed
in the form of a hand counter. In this configuration the main elements
of the flow meter described in connection with FIG. 1 are located
at the end of a hose line 40 which is in connection, via a pump,
not shown, with a tank, also not shown, containing the liquid to
be metered. The flow meter additionally includes a display device
41 which is formed by liquid-crystal display elements. The display
is on the upper side 42 of a housing 43 in the interior of which
is located, in addition to an opening valve that can be operated
by a handle 44 the rotatably movable measuring organ of the meter.
In this configuration, the generator of the meter furnishes the
supply voltage for an elecrical evaluating device which contains,
in addition to an electronic counter the display device 41. The
housing 43 also contains the measured-value pickup device of the
meter, which device generates pulses related to the flow of the
liquid being metered.
FIG. 5 shows in greater detail the circuit of the flow meter according
to FIG. 4. A voltage generator 50 which is driven by the measuring
organ or member, not shown, has its output voltage 51 coupled to
a buffer device 53 via a rectifier arrangement 52. The generator
50 supplies supply voltage via the buffer device 53 to an amplifier
54 as well as to a pulse former 55 and an electronic counting device
56. The amplifier 54 is also connected, via a line 57 to a measured-value
pickup device 58 which may be formed, for example, by an additional
tachometer generator or an electric pulse generator. The count in
the counting device 56 therefore, corresponds to the quantity of
liquid that has flowed through the flow meter. The count of the
counting device 56 is displayed in a display device 59. The latter
display device 59 may contain field-effect display elements, as
well as liquid-crystal display elements.
The advantage of the flow meter of FIGS. 4 and 5 is that, due to
the use of an electrical measured-value pickup device and electrical
evaluating device, a relatively small and, therefore, handy flow
meter is produced, which does not require an additional supply voltage
source in spite of containing these electronic components.
In the flow meter of the invention shown in FIG. 6 the generator
60 of the meter is disposed in a separate structural unit whose
housing 62 is bolted by means of screws 61 to the flange 63 of a
housing 64. The housing 64 houses the rotatably movable measuring
organ of the meter, the latter organ being connected to a shaft
65 of the generator 60. A magnet arrangement 66 attached to the
shaft 65 is set in rotary motion by the rotatably movable measuring
organ. This induces in the winding arrangement 67 surrounding the
magnet arrangement 66 an electric voltage which can be utilized
as the supply voltage.
In the flow meter of the invention shown in FIG. 7 the flow meter
is formed as a turbine counter 70 wherein a turbine wheel 72 through
which the medium to be measured flows, is supported on a shaft 73.
The shaft 73 supports on one of its ends a magnet arrangement 74
which moves in a winding arrangement 75. The winding arrangement,
thus, provides a voltage at the terminals 76 and 77 which can be
used as the supply voltage.
In summary, therefore, the present invention is a flow meter which
comprises an electrical measured-value pickup and evaluation device
which requires no separate supply voltage source, as not only the
measurement value is derived from the gaseous or liquid medium to
be measured, but the meter also includes means responsive to the
energy of such medium for supplying a supply voltage for operating
the measured-value pickup and the evaluating device. |