Abstrict A flow meter comprising a tubular main-body and a cover plate formed
by printed circuit board which carries two pressure sensing devices
tightly packed by soft rubber material for sensing the pressure
head of and the pressure difference between the inlet and outlet
of the flow meter. Since the cover plate is mounted on, and fastened
to the main-body by fastening screw, but not by adhesive to form
a complete unit, the cover plate can therefore bear high fluid pressure
without crack or damage, i.e., shall increase the capacity of bearing
pressure, the service life and accuracy, and decrease the occurrence
of malfunction to the flow meter.
Claims What is claimed is:
1. A flow meter comprising a tubular main-body and a cover plate
carrying two pressure sensing devices on one side, wherein the tubular
main-body has a venturi tube structure inside having an inlet of
convergent shape and an outlet of divergent shape, and a seat is
formed on outer surface of the tubular main-body having two separate
recessions each of which has a penetrating hole connected separately
to the convergent portion and divergent portion of the tubular main-body;
the cover plate is mounted on the seat to form a cover to the seat;
and the two pressure sensing devices carried on the cover plate
are completely and tightly packed with silicon rubber and located
separately above the corresponding penetrating hole on the tubular
main-body.
2. The flow meter as defined in claim 1 wherein the cover plate
is a printed circuit board and the two pressure sensing devices
are electric connection with the printed circuit.
3. The flow meter as defined in claim 1 wherein the cover plate
provides a rubber filling plate with two recessions on the bottom
side, and the two pressure sensing devices carried on the cover
plate are located separately in the two recessions of the rubber
filling plate, and each of recessions is filled with silicon rubber
for packing the pressure sensing devices.
4. The flow meter as defined in claim 2 wherein the cover plate
provides a rubber filling plate with two recessions on the bottom
side, and the two pressure sensing devices carried on the cover
plate are located separately in the two recessions of the rubber
filling plate, and each of recessions is filled with silicon rubber
for packing the pressure sensing devices.
5. The flow meter as defined in claim 2 wherein the seat of the
tubular main-body has aligning wall formed surrounding upper surface
of the seat, and has a leak prevention sheet installed in the space
surrounded by the aligning wall.
6. The flow meter as defined in claim 3 wherein the seat of the
tubular main-body has aligning wall formed surrounding upper surface
of the seat, and has a leak prevention sheet installed in the space
surrounded by the aligning wall.
7. The flow meter as defined in claim 4 wherein the seat of the
tubular main-body has aligning wall formed surrounding upper surface
of the seat, and has a leak prevention sheet installed in the space
surrounded by the aligning wall.
8. The flow meter as defined in claim 4 wherein the cover-plate
has aligning holes on the bottom side, and the rubber filling plate
has aligning pins corresponding to the said aligning holes, and
the aligning pins are inserted in the aligning holes.
9. The flow meter as defined in claim 7 wherein the cover-plate
has aligning holes on the bottom side, and the rubber filling plate
has aligning pins corresponding to the said aligning holes, and
the aligning pins are inserted in the aligning holes.
10. The flow meter as defined in claim 2 wherein both ends of
the tubular main-body are formed into connecting-ends for installing
a quick couplings.
11. The flow meter as defined in claim 4 wherein both ends of
the tubular main-body are formed into connecting-ends for installing
a quick couplings.
12. The flow meter as defined in claim 5 wherein both ends of
the tubular main-body are formed into connecting-ends for installing
a quick couplings.
13. The flow meter as defined in claim 7 wherein both ends of
the tubular main-body are formed into connecting-ends for installing
a quick couplings.
14. The flow meter as defined in claim 2 wherein the tubular main-body
is incorporated with a TDS water quality tester mounted on the outer
surface of the tubular main-body.
15. The flow meter as defined in claim 4 wherein the tubular main-body
is incorporated with a TDS water quality tester mounted on the outer
surface of the tubular main-body.
16. The flow meter as defined in claim 5 wherein the tubular main-body
is incorporated with a TDS water quality tester mounted on the outer
surface of the tubular main-body.
17. The flow meter as defined in claim 7 wherein the tubular main-body
is incorporated with a TDS water quality tester mounted on the outer
surface of the tubular main-body.
18. The flow meter as defined in claim 10 wherein the tubular
main-body is incorporated with a TDS water quality tester mounted
on the outer surface of the tubular main-body.
19. The flow meter as defined in claim 11 wherein the tubular
main-body is incorporated with a TDS water quality tester mounted
on the outer surface of the tubular main-body.
20. The flow meter as defined in claim 13 wherein the tubular
main-body is incorporated with a TDS water quality tester mounted
on the outer surface of the tubular main-body.
Description BACKGROUND OF THE PRESENT INVENTION
[0001] 1. Field of the Present Invention
[0002] The invention relates to a flow meter, particularly the
flow-meter having two pressure sensing devices.
[0003] 2. Description of Prior Act
[0004] Shown in FIG. 1 is the conventional type flow meter (10)
having a venturi tube structure formed inside the tubular main-body
wherein the inlet (13) of the tubular main-body has a convergent
inner diameter while the outlet (14) of the tubular main-body has
a divergent inner diameter, and a transitional neck portion is formed
between the inlet portion (13) and the outlet portion (14) so as
to form the venturi tube structure inside the tubular main-body
(11).
[0005] As for the application, the major function of the conventional
flow meter (11) is to measure pressure head (P.sub.1) at the inlet
(13) and the pressure head (P.sub.2) at the outlet (14) near the
neck of the venturi tube, and obtain the value of pressure difference
(P.sub.1-P.sub.2) between the fluid pressure at inlet (13) and outlet
(14), and then an microcomputer is employed for converting the pressure
difference (P.sub.1-P.sub.2) into flow rate and flow speed measurement
which are then displayed by digital display unit.
[0006] Moreover, in order to measure the pressure difference (P.sub.1-P.sub.2)
existing near the neck portion of the tubular main-body (11) a platform
(12) is provided on the outer surface of the tubular main-body (11)
having a small penetrating hole (15) arranged on the platform (12)
and connected to the convergent portion of the inlet (13) of the
tubular main-body; And, a recession is formed on the platform (12)
for accommodating and mounting a pressure difference sensing device
(18) which can sensing the fluid pressure at the divergent portion
of the tubular main-body (11) through the penetrating hole (16)
which is arranged as close as possible to the neck portion of the
tubular main-body (11).
[0007] Meanwhile in order to enable the upper side of the pressure
difference sensing device (18) to sense the pressure head (P.sub.1)
at the fluid inlet (13) transmitted through the penetrating hole
(15), a passage groove (19) is formed on the surface of the platform
(12), and is connected to the penetrating hole (15) and upper side
of the pressure difference sensing device (18), and then a cover
plate (17) is tightly mounted on the upper side of the platform
(12) that the upper side and the lower side of the pressure sensing
device (18) can separately sense the pressure head (P.sub.1) at
the inlet (13) transmitted through penetrating hole (15) and the
pressure head (P.sub.2) at the outlet (14) near the neck portion
transmitted through penetrating hole (16) to obtain the pressure
difference (P.sub.1-P.sub.2) which shall be transmitted to the microcomputer
for calculating the flow rate and flow speed.
[0008] However, this type of conventional flow meter (10) has three
drawbacks as follows:
[0009] First, the conventional type flow meter (10) employs only
one sensing device (18) to measure the pressure difference (P.sub.1-P.sub.2)
produced at a point near the neck portion of tubular main-body (11).
Since the upper side and lower side of the pressure difference sensing
device (18) both have to sustain the pressure head (P.sub.1) and
pressure head (P.sub.2) at the same time, malfunction always occurs
due to inability of sustaining the pressure difference variation,
and the service life of the conventional type flow meter (10) is
therefore largely reduced to result in a poor economic effectiveness.
[0010] Second, on the upper side of the platform (12) of the tubular
main-body (11) of the conventional type flow meter (10) a horizontal
passage groove (19) must be provided. However, since the passage
groove (19) is perpendicular to the penetrating hole (15) on the
platform a distortion of measurement of the pressure head (P.sub.1)
sensed by the pressure sensing device (18) is always resulted in,
and actually the flow rate and flow speed measured by the conventional
type flow meter are inaccurate.
[0011] Third, since a passage groove (19) is formed on the upper
side of the platform (12) of the conventional type flow meter (10),
a cover plate (17) must be mounted on, and tightly seal the upper
side of the platform (12). However, the pressure head (P.sub.1)
at the fluid inlet (13) transmitted through the penetrating hole
(15) on the platform (12) is sometimes greater than the fastening
force for tightly holding the cover plate (17) on the platform (12),
that results in the damage or crack of the cover plate (17) due
to inability of sustaining the pressure head (P.sub.1). This will
cause the failure of operation of conventional type flow meter (10).
SUMMARY OF THE PRESENT INVENTION
[0012] Therefore, as concluded from the above, the major purpose
of the invention is to improve the drawbacks of the conventional
type flow meter by arranging two pressure sensing devices instead
of one pressure sensing device on the flow meter, and each of the
two pressure sensing devices shall individually and separately sense
the fluid pressure at the inlet and outlet of the flow meter that
can precisely measure the pleasure difference at a point near the
throat portion produced by the fluid pressure at the inlet and outlet
of the flow meter so as to completely solve the problem of the conventional
type flow meter caused by employing only one pressure difference
sensing device, and increase the service life as well as the measuring
accuracy of the flow meter.
[0013] Another purpose of the invention is to provide a new flow
meter structure which comprises a tubular main-body having an internal
venturi tube structure and two pressure sensing devices. Since each
of the two pressure sensing devices is arranged to measure the pressure
head at the inlet and outlet of the venturi tube individually and
separately, each sensing device can therefore sustain wide range
of variation of pressure difference; particularly the two pressure
sensing devices are mounted directly on a printed circuit board,
and are tightly packed with soft rubber material. The printed circuit
board is then fastened on the outer side of the tubular main-body
by fastening screw. In addition to using the printed circuit board
as the cover plate of the tubular main-body, the printed circuit
board can also forms the flow meter with tubular main-body having
considerably strong structure. Besides, since the arrangement of
the pressure sensing device of the flow meter has a structure of
specific design, the ability to sustain fluid pressure, the measuring
accuracy and service life all are improved, and the occurrence of
malfunction is decreased that largely enhanced the applicability
of the flow meter.
[0014] The minor purpose of the invention is to provide a multiple
function flow meter by incorporating a TDS water quality tester
to the tubular main-body of the flow meter which when measuring
the flow rate of the tap water, spring water, mineral water and
different kinds of packed water the water quality such as purity
and hardness can also be tested at the same time.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0015] FIG. 1 is a sectional view and schematic drawing of a conventional
type flow meter.
[0016] FIG. 2 is the three-dimensional drawing of a flow meter
disclosed in the invention.
[0017] FIG. 3 is an exploded drawing of the flow meter shown in
FIG. 2.
[0018] FIG. 4 is a three-dimensional partial-sectional drawing
of tubular main-body of the flow meter shown in FIG. 2.
[0019] FIG. 5 is a schematic drawing showing the arrangement of
two pressure sensing devices which are directly installed on the
cover plate formed with a printed circuit board.
[0020] FIG. 6 is a schematic drawing of the cover plate shown in
FIG. 5 which shows a rubber filling plate adhered to the cover plate
and the pressure sensing devices packed with soft rubber material.
[0021] FIG. 7 is a sectional and schematic drawing showing the
application of the flow meter shown in FIG. 2.
[0022] FIG. 8 is a schematic drawing of the second embodiment of
the flow meter disclosed in the invention which schematically shows
that both ends of the tubular main-body are formed into connecting
ends special for mounting the quick coupling.
[0023] FIG. 9 is three-dimensional drawing of the third example
of embodiment of the flow meter disclosed in the invention showing
a TDS water quality tester incorporated to the tubular main-body.
DETAILED DESCRITION OF THE PREFERRED EMBODIMENTS
[0024] As shown in FIG. 2 through FIG. 7 the basic structure of
the flow meter (20) disclosed in the invention comprises a tubular
main-body (21) and a cover plate (60) carrying two pressure sensing
device (50) mounted on one side. And the most preferred embodiment
of the invention is to have the cover plate (60) formed with a printed
circuit board and two pressure sensing devices (50) installed on
the printed circuit board (60).
[0025] As shown in FIG. 4 the tubular main-body (21) has its inner
side formed into a venturi tube structure which has a throat portion
(A), i.e., the inlet portion (23) of the tubular main-body (21)
is in convergent shape, and the outlet portion (24) of the tubular
main-body (21) is in divergent shape, and between the convergent
and divergent portion is the throat (A) of the venturi tube.
[0026] As shown in FIG. 3 and FIG. 4 the tubular main-body (21)
has a seat (22) which has a recession formed on its upper surface.
However in the preferred embodiment of the invention the recession
is divided into two independent recessions (22a) and (22b), and
a small penetrating hole (25) is arranged on the bottom of the recession
(22a) to connect the convergent portion of the fluid inlet (23)
of the tubular main-body (21), while another small penetrating hole
is arranged on the bottom of the recession (22b) to connect the
divergent portion of the outlet (24) of the tubular main-body (21)
and close as much as possible to the throat (A) of the venturi tube.
[0027] In order to enable the seat (22) of the tubular main-body
(21) to provide the function for aligning the parts and components
during installation and to strengthen the structure of seat (22),
the aligning pins (27) are provided on seat (22), or aligning wall
(22c) surrounding the seat (22) can be further provided for accommodating
a leak prevention rubber sheet (30).
[0028] The main-body (31) of the leak prevention rubber sheet (30)
has two separate holes (32) positioned corresponding to the position
of the recessions (22a) and (22b) formed on seat (22) of the tubular
main-body (21). When the leak prevention rubber sheet (30) is installed
on the surface of the seat (22) the gap between the recession (22a)
and (22b) formed on the seat (22) can be eliminated, and leak prevention
effect can be achieved.
[0029] Aligning indentations (33) are provided along the circumference
of the leak prevention rubber sheet (30) and positioned corresponding
to the aligning pin (27) on the seat (22) of the tubular main-body
(21). When the leak prevention rubber sheet (30) is installed on
the seat (22), the aligning indentation (33) on the leak prevention
rubber sheet (30) and the aligning pin (27) on the seat (22) of
the tubular main-body (21) can guide each other during installation
to mount the leak prevention rubber sheet (30) in correct position
for achieving the effect of leak prevention.
[0030] Referring to FIG. 3 and FIG. 5 the cover plate (60) has
a main-body (61) formed by printed circuit board having aligning
indentations (64) arranged along the circumference and positioned
corresponding to the aligning pin (27) on the seat (22) of the tubular
main-body (21). When mounting the cover plate (60) the aligning
indentation (64) of the cover plate (60) and the aligning pin (27)
on the seat (22) of the tubular main-body (21) can align and guide
each other for mounting the cover plate (60) into correct position
on seat (22) of the tubular main-body (21).
[0031] Also referring to FIG. 3 and FIG. 7 the seat (22) of the
tubular main-body (21) has several screw holes (22d) positioned
corresponding to the fastening holes (62) on the main-body (61)
of the cover plate (60). When the cover plate (60) is correctly
mounted on the seat (22) of the tubular main-body (21), the whole
assembly of cover plate (60) and tubular main-body (21) is tightly
joined together by means of fastening screws (70) to form the assembly
as a complete unit of flow meter (20) of the invention.
[0032] Besides, since the cover plate (60) and the tubular main-body
(21) of the flow meter (20) are joined together by means of fastening
screws (70) to form a complete unit, but not by adhesive or any
other kinds of bonding agent, the capacity of bearing pressure to
the flow meter (20) is increased that can prevent the cover plate
(60) from damage or crack due to fluid pressure. In addition, by
employing the tightening force of the tightening screw (70) the
leak prevention rubber sheet (30) between the cover plate (60) and
the seat (22) of the tubular main-body (21) can be tightly fixed
to achieve the effect of leak prevention.
[0033] As shown in FIG. 3 FIG. 5 and FIG. 6 the two pressure
sensing devices (50) both have high-sensitivity pressure sensitive
chip (51) as the major element, and are installed on the main-body
(61) of the cover plate (60) by means of jump connection leading-out
wire (52) and glass plate (53) to form electric connection with
the printed circuit on the cover plate (60).
[0034] And, the two pressure sensing devices (50) are tightly packed
inside the soft rubber material (80) which, when the flow meter
is used to test the fluid flow, can completely prevent the pressure
sensing device (50) from contacting with the fluid, but can sense,
and measure the pressure of the fluid transmitted through the soft
rubber material (80).
[0035] As shown in FIG. 3 and FIG. 6 in order to have the pressure
sensing device (50) completely and tightly packed inside the soft
rubber material (80) one of the example of embodiment of the invention
chooses to adhere a rubber filling plate (40) on the main-body (61)
of the cover plate (60) before applying the soft packing rubber
material (80), i.e., the rubber filling plate (40) is correctly
installed on the main-body (61) of the cover plate (60) and two
pressure sensing devices (50) on the main-body (61) of the cover
plate (60) are accommodated inside the recessions (42) on the main-body
(41) of the rubber filling plate (40), and then the soft rubber
material (80) is filled into the recessions (42) to completely and
tightly pack the pressure sensing device (50).
[0036] As shown in FIG. 3 FIG. 6 and FIG. 9 the rubber filling
plate (40) has aligning indentations (43) along the circumference
with position arranged corresponding to the aligning pin (27) on
the seat (22) of the tubular main-body (21), therefore, after the
rubber filling plate (40) is adhered to the main-body (61) of the
cover plate (60) the aligning indentation (64) on the cover plate
(60), the aligning indentation (43) on the rubber filling plate
(40) and the aligning pin (27) can be employed to align each other,
and the aligning pin (27) will serve as a guide to enable a correct
installation of the cover plate (60) and the rubber filling plate
(40) on the seat (22) of the tubular main-body (21), so that the
rubber filling plate (40) can be evenly and tightly mounted on the
leak prevention rubber sheet (30) to achieve the desired leak prevention
effect when the cover plate (60) and the tubular main-body (21)
are tightened by tightening screw (70) to form a complete unit.
[0037] Further, in order to correctly and easily mount and adhere
the rubber filling plate (40) on the cover plate (60), aligning
holes (63) are provided on the main-body (61) of the cover plate
(60), and aligning pins (44) are provided on the main-body (41)
of the rubber filling plate (40) positioned corresponding to the
aligning holes (63) on the cover plate (60).
[0038] Therefore, the installation of the rubber filling plate
(40) can be made in such a way that after applying the adhesive
on the main-body (41), the rubber filling plate (40) can be mounted
on the cover plate by inserting the aligning pin (44) into the aligning
hole (63) on the cover plate (60) to achieve the purpose of easily
to adhere the rubber filling plate (40) on correct position.
[0039] As concluded above, when the cover plate (60) and the tubular
main-body (21) are assemble together to form the flow meter (20)
of this invention as shown in FIG. 7 the two pressure sensing devices
(50) are located separately at the upper side of the recession space
(22a) and (22b) on the seat (22) of the tubular main-body (21),
and are tightly packed inside the soft rubber material (80). Therefore,
only one side of each pressure sensing device (50) bears fluid pressure
especially without contact with fluid, thus the pressure sensing
device (50) can bear even wider range of variation of fluid pressure.
[0040] Moreover, since the cover plate (60) of the invention is
a printed circuit board which directly forms electric connection
with the pressure sensing device, the measuring signal loss or distortion
is decreased, and the measuring accuracy of the flow meter (20)
is increased.
[0041] As shown in FIG. 7 the flow meter (20) of this invention
employs two pressure sensing devices (50) on cover plate (60) to
sense separately the pressure head P.sub.1 at fluid inlet (23) transmitted
through penetrating hole (25) on the tubular main-body (21) and
the pressure head P.sub.2 at fluid outlet (24) transmitted through
penetrating hole (26) near throat (A), and then the measured pressure
head P.sub.1 and P.sub.2 are sent to a microcomputer through cover
plate (60) to calculate the value of pressure difference (P.sub.1-P.sub.2)
and convert the pressure difference value into flow rate and flow
speed, and then display the calculated value on digital display.
[0042] As shown in FIG. 8 another embodiment of the flow meter
(20) disclosed in this present invention may have connecting means
(211) on either end or both ends for mounting a set of quick coupling
(90) that enables the flow meter (20) to further have the function
of quick connection. The connecting means (211) may be formed in
the form of inner screw thread or outer screw thread to enable a
screw-thread connection between the flow meter (20) and the fluid
piping system.
[0043] As shown in FIG. 9 further another embodiment of the flow
meter (20) disclosed in this present invention can further have
a seat (28) formed on the outer surface of the tubular main-body
(21) for mounting a TDS (Total Dissolved Solids) water quality tester
(95) for testing total dissolved solids of pollutant, impurity and
unknown chemical material contained in the water that enables the
flow meter (20) to possess the function of testing water hardness
and water purity.
[0044] When the flow meter (20) disclosed in the present invention
is employed for testing the flow rate of tap water, sprint water,
mineral water and different kinds of packed water the hardness as
well as the purity of these kinds of water can also the tested at
the same time. |