Abstrict A suspended body flow meter for flowing media with a measuring
tube, with a suspended body movable in the direction of flow and
located in the measuring tube, with at least one permanent magnet
connected with the suspended body, with a meter housing, with at
least one rotatable follower magnet following the motions of the
permanent magnet connected with the suspended body and located outside
the measuring tube in the meter housing and with a display device
converting the motions of the follower magnet and located in the
meter housing. The meter housing is designed so that at least one
slide-in guide is provided for a slide-in element bearing mechanical
and/or electrical functional units.
Claims What is claimed is:
1. A suspended body flow meter for flowing media, with a measuring
tube, with a suspended body movable in the direction of flow located
in the measuring tube, with at least one permanent magnet connected
with the suspended body, with a meter housing, with at least one
rotatable follower magnet following the motions of the permanent
magnet connected with the suspended body and located outside the
measuring tube in the meter housing, and with a display device converting
the motions of the follower magnet and located in the meter housing,
wherein the meter housing has at least one slide-in guide for a
slide-in element bearing mechanical and/or electrical functional
units, the slide-in element bears at least one threshold value pointer
device having a threshold value pointer, and the threshold value
pointer device bears an electrical contactor.
2. A meter housing for a suspended body flow meter for flowing
media, with at least one rotatable follower magnet following the
motions of a permanent magnet connected with a suspended body movably
mounted in the direction of flow in a measuring tube, and with a
display device which converts the motions of the follower magnet,
wherein at least one slide-in guide for a slide-in element bearing
mechanical and/or electrical functional elements is provided, the
slide-in element bears at least one threshold value pointer device
having a threshold valve pointer, and the threshold valve pointer
device bears an electrical contactor.
3. The suspended body flowmeter in accordance with claim 1 or
the meter housing in accordance with claim 2 wherein the slide-in
element is made as a scale carrier.
4. The suspended body flow meter in accordance with claim 1 or
the meter housing in accordance with claim 2 wherein the threshold
value pointer device has a recess making it possible to push the
threshold value pointer device laterally onto a bearing bushing
of a pointer shaft and forming a radial bearing by interacting with
the bearing bushing.
5. The suspended body flow meter in accordance with claim 1 or
the meter housing in accordance with claim 2 wherein the threshold
value pointer device is connected with the associated slide-in element
via a slot guide.
6. The suspended body flow meter in accordance with claim 1 or
the meter housing in accordance with claim 2 wherein the pointer
is provided with a counterweight, and wherein the counterweight
of the pointer forms an actuating lug for the electrical contactor.
7. The suspended body flow meter in accordance with claim 1 or
the meter housing in accordance with claim 2 wherein the slide-in
element is made as a printed circuit board.
8. The suspended body flow meter or meter housing in accordance
with claim 7 wherein the printed circuit board bears at least the
electronic components necessary for controlling the electrical contactors.
Description In accordance with a first teaching, the invention concerns a suspended
body flow meter for flowing media, with a measuring tube, with a
suspended body movable in the direction of flow and located in the
measuring tube, with at least one permanent magnet connected with
the suspended body, with a meter housing, with at least one rotatable
follower magnet following the motions of the permanent magnet connected
with the suspended body and located outside the measuring tube in
the meter housing, and with a display device which converts the
motions of the follower magnet and is located in the meter housing.
In accordance with a second teaching, the invention concerns a
meter housing for a suspended body flow meter for flowing media,
with at least one rotatable follower magnet following the motions
of a permanent magnet connected with a suspended body mounted movable
in the direction of flow in a measuring tube and with a display
device which converts the motions of the follower magnet.
BACKGROUND OF THE INVENTION
Suspended body flow meters have been used since the middle of the
last century for determining volume and mass flows in closed pipelines.
Even today they can be found in approximately every fifth flow meter
in the chemical and materials processing industry.
A suspended body flow meter, in its simplest form, consists of
a conical measuring tube and the suspended body. The measuring tube
is a conical tube expanding upward through which the liquid or gas
flow to be measured flows upward, in which tube the suspended body,
an appropriately shaped, vertically freely movable measuring element,
is located, which, together with the measuring tube, forms a restrictor.
The density of the suspended body is greater than that of the flowing
medium. Depending on the flow, the suspended body adjusts itself
in the steady state at a specific level position in the measuring
tube, which results from the equilibrium of the hydrodynamic force
acting on the suspended body, caused by the flow, and the difference
of the weight and buoyancy forces of the suspended body. This level
position is either read by the observer directly via a scale on
a glass measuring tube or transferred by a magnetic coupling to
an external scale and/or an electric sensor. The suspended body
flow meter under consideration is such a meter in which the level
position of the suspended body can be transferred by means of a
magnetic coupling via an external follower magnet to a scale located
in the meter housing and/or an electric sensor also located in the
meter housing.
In addition to the designs with conical measuring tube and spherical
or sharp-edged suspended bodies, straight measuring tubes with a
measuring orifice and a conical suspended body within the orifice
opening can be used. Also it is conceivable not to arrange the measuring
tube vertically, in this case it being necessary to replace the
weight force of the suspended body with the spring force of a spring
acting on the suspended body.
The invention under consideration essentially concerns the design
of the meter housing which holds at least the follower magnet and
the display device converting the motion of the follower magnet,
which is independent of the variation possibilities described in
the case of the design of a suspended body flow meter. The second
teaching of the invention here takes account of the possibility
that, in the case of measurement tubes already incorporated into
closed pipelines, there is the possibility of backfitting only the
meter housing if necessary.
The known meter housings used in connection with suspended body
flow meters for flowing media are all designed in such a way that
additional mechanical and/or electrical functional units can only
be connected with either the meter housing itself via screw connections
or a bearing bushing of the pointer shaft bearing the pointer or
the pointer shaft itself via push-on or screw connections. In the
first place, it should be mentioned that suspended body flow meters
are regularly supplied only in one basic design, therefore perhaps
without a transmitter converting the motions of the follower magnet
into electric signals or without a threshold value display arrangement
mechanically displaying or electrically outputting the reaching
of a minimum or maximum range of the suspended body. In the case
of backfitting this suspended body flow meter with further functional
units, the known methods of attachment entail problems, since they
are difficult to carry out depending on the position of the suspended
body flow meter and, in particular, they require increased caution
in the connection with the pointer shaft.
A particular problem results from the fact that in a number of
suspended body flow meters it is usual to mount on the pointer shaft
a counteraeight or calibration weight with a center of gravity outside
of the pointer axis for calibrating the suspended body flow meter,
the position of which is determined individually in a calibration
process for each suspended body flow meter. Now in order to mount
the threshold value pointer arrangement with a possibly associated
electrical contactor onto the bearing bushing for the pointer shaft
and the associated actuating lugs on the pointer shaft itself, in
the case of this suspended body flow meter, the counterweight or
calibration weight must be removed from the pointer shaft. Thus,
the backfitting of this known suspended body flow meter requires
that then the suspended body flow meter concerned is subjected to
recalibration for determining the position of the counterweight
or calibration weight. This is very problematical for various reasons.
First, the suspended body flow meter has to be removed from the
pipeline system of the plant for calibration, which, as a rule,
requires an interruption of the production process. In the second
place, the calibration requires trained special personnel, which
are not available at every plant, and, in addition, increased costs
if they are available. Finally, in the third place, it is problematical
that the necessary calibration only is to be performed by means
of a calibrating device for adjusting a known flow through the suspended
body flow meter. Of course, providing such a calibrating device
entails considerable costs.
SUMMARY OF THE INVENTION
Therefore, the object of the invention is to design and further
develop the known suspended body flow meters for flowing media in
such a way that they are equipped, or can be backfitted, with meter
housings which permit backfitting of the suspended body flow meters
with additional functional units without problems and without trained
personnel.
In accordance with the first teaching of the invention, the previously
derived and indicated object is solved by the fact that the meter
housing has at least one slide-in guide for a slide-in element bearing
mechanical and/or electrical functional units. In accordance with
the second teaching of the invention, the previously derived and
indicated object is solved by the fact, a meter housing for a suspended
body flow meter has at least one slide-in guide for a slide-in element
bearing mechanical and/or electrical functional elements. The design
according to the first and second teachings of the invention advantageously
ensures that the backfitting with additional mechanical and/or electrical
functional units can be performed very simply and rapidly without
special personnel and without subsequently required calibration.
The backfitting is simplified to the degree that it can be performed,
for example, by a plant electrician within the framework of his
usual activities. In addition, the invention also insures that the
process of producing a correspondingly designed meter housing is
considerably simplified with respect to the known meter housings.
In accordance with a first advantageous design, a device in accordance
with the invention is characterized by the fact that the slide-in
element is designed as a scale carrier. Such a design simplifies,
in particular in the production process, using one and the same
meter housing in connection with measuring tubes of different nominal
widths and a correspondingly adapted scale carrier. Particularly
advantageous in this connection is the simultaneous realization
of the present teachings in accordance with the invention in connection
with the teaching disclosed in commonly owned application Ser. No.
08/926555 filed Sep. 10 1997 whose disclosure is incorporated
by reference herein, which concerns a suspended body flow meter,
which is equipped with a follower magnet, which makes it possible
to use scales of equal spreading in spite of different nominal values
of the measuring tube. In addition, backfitting by means of further
slide-in elements is simplified, since the scale carrier can be
disassembled very easily and thus also providing access to further
slide-in elements from the top.
It is especially advantageous to design the devices in accordance
with the invention so that the slide-in element bears at least one
threshold value pointer arrangement having a threshold value pointer.
The assembly of such a threshold value pointer arrangement has always
been exceedingly expensive in the case of prior art suspended body
flow meters and regularly required, as already described initially,
a recalibration of the suspended body flow meter. By means of the
design in accordance with the invention, it is ensured that the
assembly of a threshold value pointer arrangement can be performed
in minutes by personnel who are not specially trained, therefore,
perhaps, by a plant electrician.
The threshold value pointer arrangement in accordance with the
invention, located on the slide-in element, is designed particularly
advantageously in such a way that it has a recess making possible
lateral sliding onto the bearing bushing of the pointer shaft forming
a radial bearing interacting with the bearing bushing. In the case
of a design of this type, the recess provided in the threshold value
pointer arrangement simultaneously serves as a stop for the slide-in
element bearing the threshold value pointer arrangement and as a
radial bearing, which makes possible a centered turning of the threshold
pointer arrangement around the axis of the pointer.
The necessary guiding of the threshold value pointer arrangement
in addition to the radial bearing formed by the bearing bushing
and the recess is provided particularly advantageously by the fact
that the threshold value pointer arrangement is connected via a
slot guide with the associated slide-in element. In this case, a
slot running in the circumferential direction, provided in the threshold
value pointer arrangement, works together with a fastening bolt
provided in the slide-in element as a connecting link guide. Such
an attachment is particularly simple to make and, moreover, makes
it possible to attach, for example, two threshold pointer arrangements
with a single attachment bolt, so that these are capable of turning
around the axis of the pointer in interaction with the bearing bushing.
If the threshold value pointer arrangement simultaneously bears
the electrical contactor, it is especially easy to ensure that with
the insertion of the associated slide-in element, both the mechanical
indication of reaching the threshold values for the minimum and
maximum ranges by means of the threshold value pointer, as well
as the electrical display of reaching the minimum and maximum range
by means of the electrical contactor, are possible.
A device in accordance with the invention is further simplified
because the counterweight of the pointer forms an actuating lug
for the electrical contactor. By means of this measure, it is possible
to avoid using separate actuating lugs on the pointer shaft.
If the slide-in element is designed further as a printed circuit
board, it is possible by means of this measure, at the same time
to mount on the slide-in element, besides the mechanical functional
unit, an electrical functional unit, which can then simply be connected
via electrical screw or plug connections with the remaining electrical
components of the suspended body flow meter.
If the slide-in element bearing the threshold pointer arrangement
is also designed simultaneously as a printed circuit board, it is
particularly advantageous that the printed circuit board also bears
necessary electronic components for controlling the electrical contactor.
This creates a functional unit which permits equipping an already
existing device with a mechanical and electrical minimum and maximum
display in a single process taking only a few minutes.
In particular there are different possibilities for equipping and
rebuilding the suspended body flow meter or the meter housing in
accordance with the invention. Reference is made here, on the one
hand, to the dependent patent claims, and, on the other hand, to
the description of preferred embodiments in connection with the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 shows an exploded view of a first embodiment of a meter
housing in accordance with the invention for a suspended body flow
meter,
FIG. 2 shows a perspective view of an embodiment of a threshold
value pointer arrangement in accordance with the invention,
FIG. 3 shows a side view, partially cut away, of a second embodiment
of a meter housing in accordance with the invention for suspended
body flow meters, and
FIG. 4 shows a suspended body flowmeter that may be associated
with the FIG. 1 meter housing.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
FIG. 1 of the drawings shows a meter 50 depicted in FIG. 4 housing
1 for a suspended body flow meter with a measuring tube 52 with
a suspended body 54 mounted in the measuring tube and movable in
the direction of flow, and with a permanent magnet 56 connected
with the suspended body. A rotatable follower magnet 58 following
the motions of the permanent magnet connected with the suspended
body, is located in a housing bottom 2 of the meter housing 1 in
FIG. 1. The previously mentioned pending application is to be consulted
for details of the design of this follower magnet and the flowmeter
as a whole. The display device located within the meter housing
1 which converts the motions of the follower magnet, in the first
embodiment of a meter housing shown in FIG. 1 is made as a pointer
4 located on a pointer shaft 3 connected with the follower magnet.
The pointer shaft 3 is mounted in a bearing bushing 5 in the embodiment
shown here. In accordance with the invention, the meter housing
1 has three slide-in guides 6 7 8 for slide-in elements 910 bearing
mechanical and/or electrical functional units.
In the case of the first embodiment of a meter housing in accordance
with the invention, shown in FIG. 1 a transmitter 11 converting
the motions of the follower magnet into electrical signals is attached
to the housing bottom 2.
The first slide-in element 9 is designed as a scale carrier in
the first embodiment shown in FIG. 1. This first slide-in element
9 has a recess for the pointer shaft 3. In addition to the scale
division 12 printed on the first slide-in element 9 there is a
slot 13 through which the ends of threshold value pointers 1415
which display the maximum or minimum range, are visible. The threshold
value pointers 14 15 serve, as is known from the prior art, for
marking maximum and minimum ranges, within which the current flow
value is critical and requires a correction. The first slide-in
element 9 designed as a scale carrier is pushed into the uppermost
slide-in guide 6 of the meter housing 1. This uppermost slide-in
guide 6 differs from the two lower slide-in guides 78 since it
is directly visible through a cover, not shown, and thus should
be made visually attractive.
The second slide-in element 10 is capable of being pushed into
the lowest slide-in guide 8 shown in the embodiment shown in FIG.
1 which element bears two threshold display arrangements 16 17
in each case having a threshold pointer 14 15.
An embodiment of such a threshold pointer arrangement 16 is shown
enlarged in FIG. 2. This embodiment of a threshold value pointer
arrangement 16 consists of a semi-circular base plate 18 a pointer
attachment 19 the threshold value pointer 14 and an attachment
20 for electrical contactors not shown here. Preferably, this threshold
value pointer arrangement 16 is made in one piece out of sheet metal.
A recess, which makes it possible to push the threshold value pointer
arrangement 16 sideways onto the bearing bushing 5 of the pointer
shaft 3 now is provided in the threshold value pointer arrangement
16. The radius of the recess in this case is matched to the radius
of the bearing bushing 5 exactly, so that the recess and the bearing
bushing 5 interact creating a radial bearing receiving forces directed
radially inward.
For receiving any forces directed radially outward, the threshold
value pointer arrangement has a slot 21 extending parallel to the
circumference, which forms a slot guide in the nature of a connecting
link guide, shown in FIG. 1 for the bolt 22 attached to the second
slide-in element 10. This slot guide, together with the radial bearing
formed by the recess and the bearing bushing 5 ensures that the
threshold value pointer arrangement can rotate around the pointer
axis. Instead of a bolt 22 it is also possible to provide a screw
which can be tightened according to the setting of the threshold
value pointer arrangements 16 17 in order to fix these settings.
This fixing of these settings can alternatively be ensured by means
of a gluing point.
FIG. 1 also shows that the threshold value pointer arrangements
16 17 bear electric contactors 23 24 on their attachments. The
electrical contactors 23 24 in each case have slots, into which
an actuating lug 25 connected with the pointer shaft 3 depending
on the pointer position can enter and can influence the electrical
contactors 23 24. In the embodiment shown, the actuating lug 25
is made in one piece with the pointer 4 at the same time forming
the counterweight to the weight of the pointer 4 and thus provides
for the balancing of the moments on the pointer shaft 3. Therefore,
as opposed to known suspended body flow meters, the actuating lug
25 is already provided in each basic design of the associated meter
housing, so that when backfitting one or more threshold pointer
arrangements, no additional actuating lug has to be attached to
the pointer shaft 3.
Finally, in the case of the embodiment shown in FIG. 1 the second
slide-in element 10 is made as a printed circuit board, this bearing
at least the electronic components, not shown here, necessary for
controlling the electrical contactors. It is conceivable to mount
further electronic components, perhaps a driver for bridging over
great distances between the suspended body flow meter and a central
command post on the printed circuit board forming the second slide-in
element 10 in addition to the electronic components for controlling
the electrical contactors.
FIG. 3 of the drawing shows a second embodiment of a meter housing
26 in accordance with the invention. In the case of this second
embodiment, all three slide-in guides 27 28 29 are designed as
slots in the side walls 30 31. In contrast to this, in the first
embodiment shown in FIG. 1 the two lower slide-in guides 7 8 consist
of plastic guide rails set on the side walls. Also a third slide-in
element 32 bearing mechanical and/or electrical functional units
is inserted in the second embodiment shown in FIG. 3. The electrical
connections between the slide-in elements 10 32 and the transmitter
11 respectively, and an outer voltage supply are provided via electrical
plug or screw connections 33 34 35.
Finally, FIG. 3 of the drawing also shows a cover 36 not shown
in FIG. 1 which consists of a transparent window 37 and a casing
38. All further components of the second embodiment in common with
the first embodiment shown in FIG. 1 are provided with the identical
reference numbers. |