Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DEVICE FOR DYNAMICALLY MEASURING
BUBBLE CON1~r~1 OF FLOWING LIQUID
BACKGROUND OF THE INVENTION -
The present invention relates to a device for dynamically
measuring the bubble content of a flowing liquid. More
particularly, the invention relates to a device provided in a
conveyance passage for a flowing liquid, as may be used in the
chemical or mechanical industries, or provided in a simple
bypass for the conveyance passage, so that the bubble content
o of the flowing liquid and the bubble quantity of dissolved gas
in the flowing liquid can be dynamically measured without
extracting any of the liquid therefrom.
When a liquid such as a lubricating oil and a liquid
containing a polymer, a surface active agent or the like flows
through a passage with agitation, bubbles are likely to be
produced in the liquid. The bubbles contained in the liquid
are likely to cause various problems, such as an inaccurate
measurement of the flow rate of the liquid, or, in the case
that the liquid is a lubricating oil, a drop in the efficiency
of operation of a hydraulic apparatus operated by the liquid
and abnormal wear of the lubricated sliding surfaces of the
machine. Although it is often necessary to dynamically,
quickly and accurately measure the bubble content of a liquid,
no appropriate measuring device has heretofore been available.
2s Conventionally, a sample of the liquid has been extracted from
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a passage for the liquid and subjected to a gas chromatography
or a static separation process. However, such procedures are
time consuming, the bubbles in the liquid are likely to
disappear, and it is difficult to accurately measure the bubble
content of the liquid.
Accordingly, to overcome the above problems, a method and
a device for dynamically measuring the bubble content of a
flowing liquid without extracting any of the liquid from a
passage were disclosed in U.S. Pat. No. 5,041,990. The device
lo is installed in a conveyance passage of a bubble-containing
liquid or in a bypass of the passage. The device includes a
density sensor sensitive to the density of the bubble-
containing liquid, a pressure sensor, a temperature sensor, a
pressure calculation circuit, a temperature calculation
circuit, a bubble content calculation circuit, a control panel,
and a bubble content display panel. The density of the
liquid, which changes depending on the bubble content of the
liquid, is first measured. The pressure calculation circuit,
the temperature calculation circuit, and the bubble content
calculation circuit then carry out calculations in accordance
with a predetermined formula and an instruction from the
control panel to determine the bubble content of the flowing
liquid at a standard pressure and a standard temperature. The
bubble content determined in this manner is indicated on the
bubble content display panel.
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Although the bubble content of the liquid at high pressure
can be measured by the method and device disclosed in the
above-mentioned patent, there is still such a problem that it
is difficult for the method and the device to dynamically
measure the bubble content of the liquid at low pressure and
the quantity of dissolved gas in the liquid.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to
overcome the problems described above regarding measurements.
lo It is a specific object of the invention to provide a device
which includes a mass flow meter, a volumetric flowmeter and
passage changeover valves, in addition to the prior art
disclosed in U.S. Pat. No. 5,041,990, and which operates in
accordance with improved calculation formulae so that the
bubble content of a flowing liquid can be measured accurately
at either high pressure or low pressure, and the bubble
quantity of dissolved gas in the flowing liquid without
extracting the liquid.
If the device of the present invention is an integrated
type, the device is installed in a conveyance passage in which
the bubble-containing liquid flows. The device includes
pressure regulation valves for regulating the pressure of the
bubble containing liquid, a mass flowmeter for measuring the
mass flow rate of the liquid, a volumetric flowmeter for
measuring the volumetric flow rate of the liquid, a pressure
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sensor for measuring the pressure of the liquid, a temperature
sensor for measuring the temperature of the liquid, and passage
changeover valves for altering the order of flow of the liquid
through the mass flowmeter and the volumetric flowmeter.
If the device is of a separate "stand-alone~ type, it is
installed in a bypass of the conveyance passage. In this case,
the pressure regulation valves, the mass flowmeter, the
volumetric flowmeter, the pressure sensor and the temperature
sensor are connected to the bypass which connects to the
lo conveyance passage with pipe joints to introduce the liquid
into the bypass, and a pump having a function of circulating
the liquid in the pump is installed in the bypass.
In either case, the device further includes a pressure
calculation circuit, a temperature calculation circuit, a
bubble content calculation circuit, a control panel, a bubble
content display panel, a pressure display panel and a
temperature display panel.
The mass flow rate, volumetric flow rate, pressure and
temperature of the bubble-containing liquid flowing in the
conveyance passage or the bypass are measured and subjected to
calculations in the pressure calculation circuit, the
temperature calculation circuit and the bubble content
calculation circuit in accordance with formulae tl), (2) and
(3) given below, so that the bubble content of the flowing
liquid at either high pressure or low pressure and the bubble
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quality of disolved gas in the flowing liquid due to a change
in pressure of the liquid can be dynamically, quickly and
accurately determined in terms of a standard pressure (such as
an absolute pressure of 1.03 kg/cm2) and a standard temperature
s (such as 15~C).
ho VhlO + Vhso ~ ~ ~ ( 1 )
lo VllO; V180 . . . ( 2)
xso = X1~ XbO
In the formulae, Vh~o~ Vl~O~ Vh10~ VllO~ Xbo~ Xlo and Xso
respectively denote the volume of the bubbles contained in the
liquid at the standard pressure and the standard temperature
for high pressure, the volume of the bubble in the liquid at
o the standard pressure and the standard temperature for low
pressure, the volume of the liquid at the standard pressure and
the standard temperature for high pressure, the volume of the
liquid at the standard pressure and the standard temperature
for low pressure, the bubble content (% by volume) of the
liquid at the standard pressure and the standard temperature
for high pressure, the bubble content (% by volume) of the
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liquid at the st~n~Ard pressure and the stAn~Ard temperature
for low pressure, and the bubble quantity (% by volume) of
the dissolved gas in the liquid at the time of a change in
the pressure of the liquid from high pressure to low pressure
at the standard pressure and the stAn~Ard temperature.
The gas bubble content can be calculated in accordance
with the following formula:
Pl ~Pm 273+t P
. --. 100
Pl Pa 2 73+to Po
XO = . . . ( 4 )
Pl ~Pm VCF ( t ) Pl ~Pm 273+to P
1-- . +
P~~Pa~ VCF(to) Pl--Pa 273+t Po
wherein:
X0 = gas bubble content by volume percentage in the
flowing liquid at toC and P0 kg/cm2 abs.
Pc = density of gas-free liquid in g/cm3 at t~C and
P kg/cm2 abs.
Pa = gas density in g/cm3 at t~C and P kg/cm2 abs.
Pm = average density of the flowing liquid in g/cm3 at
t C and P kg/cm2abs calculated in accordance with a
volumetric flow rate (Vf) and a mass flow rate (Wf) of the
flowing liquid
(Pm = Wf/Vf) -
to= normalized temperature in ~C.
t = the flowing liquid temperature in ~C
P0= normalized pressure in kg/cm2 abs.
P = the flowing liquid pressure in kg/cm2 abs.
VCF(to) = volume correction factor of gas-free liquid at
~r
~"
2~ ~ ~ 4 Q 8 ~
a temperature of to~C, VCF(to) = p~O/p~ 15~ where p~ ~5 and p~O
are the density of gas-free liquid at a temperature of 15~C
and to~C, respectively.
VCF(t) = volume correction factor of gas-free liquid of
a temperature of t~C. VCF(t) = P~/P~ 15~ where p~ ~5 and p~ are
the density of gas-free liquid at a temperature of 15~C and
t~C, respectively.
In the above formula (4), the denominator
rP~~Pm VCF(t) P~ ~Pm 273+to P
1-1 . + ~
lP~~Pa VCF(to) P~~Pa 273+t PO
corresponds to Vh~o + VhAo and V"O + Vlao~ respectively, and the
numerator
P~ ~Pm 273+t P
P~~Pa 273+to Po
corresponds to VhaO and V1aO, respectively.
Fig. 5 is a diagram indicating schematically the
obtention of the various parameters and the calculations
carried out by the data processor.
In the device provided in accordance with the present
invention, data necessary for the calculation of the bubble
content of the flowing liquid are entered through the control
panel. The bubble-cont~;n;ng liquid is then caused to flow
through the conveyance passage or the bypass. If the liquid is
caused to flow through the conveyance passage, the mass flow
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rate, volumetric flow rate, pressure and temperature of the
liquid are measured and the calculations are thereafter made by
the pressure calculation circuit, the temperature calculation
circuit and the bubble content calculation circuit. If the
liquid is caused to flow through the bypass, the liquid is
introduced into the bypass by the pump having a circulating
function for pulverizing the bubble in the liquid to uniformly
disperse the pulverized elements of the bubble, the mass flow
rate, volumetric flow rate, pressure and temperature of the
lo liquid are then measured, and the calculations are thereafter
made by the above-mentioned circuits. The bubble content of
the liquid flowing in the conveyance passage or the bypass
passage can then be dynamically, quickly and accurately
determined in terms of the standard pressure and the standard
temperature, and then displayed to the operator on the bubble
content display panel.
When the bubble content of the flowing li~uid at high
pressure and that of the liquid at low pressure are to be
alternately measured by the device through shifting the passage
changeover valves, the liquid is caused to flow through the
conveyance passage or the bypass and set a high pressure
or low pressure by the pressure regulation valves and the
order of flow of the liquid through the mass flowmeter and that
of the li~uid through the volumetric flowmeter is then altered
2s by shifting the passage changeover valves, so that the mass
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flow rate, volumetric flow rate, pressure and temperature of the
liquid are measured at high pressure or at low pressure. The
measured quantities are sub~ected to the calculations by the
pressure calculation circuit, the temperature calculation
circuit and the bubble content calculation circuit so that the
bubble content of the liquid at high pressure and of low
pressure is determined in terms of the standard pressure and
the standard temperature, and displayed on the bubble content
display panel. The bubble content of the flowing liquid at
o high pressure and at low pressure can thus be alternately
measured, and then indicated on the panel.
When the bubble content of the flowing liquid at high
pressure set by the pressure regulation valves and that of the
flowing liquid at low pressure set by the valves are to be
simultaneously measured by the device, the bubble-containing
liquid is caused to flow through the conveyance passage or the
bypass, the volumetric flow rate, pressure and temperature of
the liquid set at high pressure are measured, the mass flow
rate of the liquid is then measured, and the volumetric flow
rate, pressure and temperat~re of the liquid set at low
pressure by the downstream pressure regulation valve are
thereafter measured. The measured quantities are subjected to
calculations by the pressure calculation circuits, the
temperature calculation circuits and the bubble content
calculation circuits for high pressure and for low pressure so
that the bubble content of the liquid at high pressure and low
pressure are determined in terms of the standard pressure and
the standard temperature in accordance with calculation
formulae (1) and (2), and then indicated on the respective
s bubble content display panels.
In accordance with calculation formula (3), the difference
between the bubble content of the liquid at low pressure and
that of the liquid at high pressure can be determined as the
bubble quantity of the dissolved gas in the liquid due to the
change in the pressure thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a cutaway view of an integrated-type device of
the invention for dynamically measuring the bubble content of
a flowing liquid, which is directly installed in a conveyance
passage for the liquid;
Fig. 2 is a block diagram of the device of Fig. 1;
Fig. 3 is a cutaway view of a separate type device for
dynamically measuring the bubble content of a flowing liquid,
which i3 installed in a bypass for the liquid;
Fig. 4 is a block diagram of the separate type device; and
Fig 5. is a diagram showing the operation of a data
processor used in the above embodiments.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Two preferred embodiments of the present invention are
hereafter described. However, the invention is not confined to
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These embodiments.
Embodiment 1:
One of the two preferred embodiments is an integrated-
type device intended for dynamically measuring the bubble content
of a flowing liquid and which is installed in the mixed oil
conveyance passage of a mixer for mixing a lubricating oil with a
polymer. The device includes a pressure sensor 5, a pressure
calculation circuit (a pressure signal amplifier) 6, a
temperature sensor 7, a temperature calculation circuit (a
temperature signal amplifier) 8, a volumetric flowmeter (a
volumetric flow sensor) 9, a volumetric flow amplifier 30, a mass
flowmeter (a mass flow sensor) 10, a mass flow amplifier 31,
pressure regulation valves 11, passage changeover valves 12, a
bubble content calculation circuit (a data processor) 13 which
operates in accordance with bubble content calculation formulae
(1) and (2) above, a control panel (an operation panel) 14, a
bubble content display panel 15, a pressure display panel 16 and
a temperature display panel 17, as shown in Figs. 1 and 2. These
components are provided in housing box 18. The pressure sensor
5, the temperature sensor 7, the volumetric flowmeter 9, the mass
flowmeter 10, the pressure regulation valves 11 and the passage
changeover valves 12 are connected to each other by pipes as
shown. The housing 18 is provided in the conveyance passage 1 of
the mixer in such a manner that the pipes of the device are
connected to the passage by pipe joints A. The sensors 5 and 7,
--11--
the flowmeters 9 and 10, the flow amplifiers 30 and 31, the
calculation circuits 6, 8 and 13, and the panels 14, 15, 16 and
17 are electrically coupled together by wires. The control panel
14 can be manipulated in front of the device. The values shown
on the bubble content display panel 15, the pressure display
panel 16 and the temperature display panel 17 can be seen in
front of the device.
Embodiment 2:
The second embodiment is a separate type device intended
for dynamically measuring the bubble content of a flowing liquid
and which is installed in a bypass of the lubricating oil
conveyance passage of a 2,000 cc four-cycle engine for a motor
vehicle. The device includes a pump 3 having a function of
circulating the liquid in the pump, a connection pipe 4, a high-
pressure section including a pressure sensor 5, a pressure
calculation circuit (a pressure signal amplifier) 6, a
temperature sensor 7, a temperature calculation circuit (a
temperature signal amplifier) 8, a volumetric flowmeter 9, a
volumetric flow amplifier 30, a pressure regulation valve 11, a
bubble content calculation circuit ( a data processor) 13
operating in accordance with calculation formula (1) above, a
bubble content display panel 15, a pressure display panel 16 and
a temperature display panel 17, a low-pressure section including
a pressure sensor 5, a pressure calcualtion circuit (a pressure
signal amplifier) 6, a temperature sensor 7, a temperature
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~0 ~ ~ # ~
calculation circuit (a temperature signal amplifier) 8, a
volumetric flowmeter 9, a volumetric flow amplifier 30, a
pressure regulation valve 11, a bubble content calculation
circuit (a data processor) 13 operating in accordance with
calculation formula (2), a bubble content display panel 15, a
pressure display panel 16 and a temperature display panel 17, a
mass flowmeter (a mass flow sensor) 10, a mass flow amplifier 31,
and a control panel (an operation panel) 14, as shown in Figs. 3
and 4. These components are provided in housing boxes 18. Two
tapped holes are provided in the lubricating oil conveyance
passage 1 of the engine. The bypass 2 is connected to the
passage by pipe joints A screw-engaged in the tapped holes. The
sensors, the calculation circuits, the flowmeters, the flow
amplifiers and the panels are electrically coupled together by
wires so that the device is composed of a bubble content
measuring detector 19 connected to the bypass 2, and a bubble
content measuring data processor 20 electrically coupled to the
detector.
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8 ~
With the device of the present invention, a flowing liquid
containing bubbles does not need to be extracted from a passage
for the liquid for measuring the bubble content of the liquid.
For this reason, the bubble content can be measured as he
liquid remains flowing in the passage. Moreover, the bubbles
do not disappear by the measurement. Since pressure regulation
valves, a volumetric flowmeter, a mass flowmeter and so forth
are provided and novel calculation formulae are employed, the
bubble content can be dynamically, quickly and accurately
measured not only at high pressure, as in the conventional
case, but also at low pressure, and the bubble quantity of the
dissolved gas in the liquid due to a change in the pressure
thereof can be dynamically, quickly and accurately measured.
-13A-
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The bubble content measuring detector of a separate type
device such as the second embodiment can be used in a severe
environment of high or low temperature, while the bubble
content measuring data processor of the device can be used in
a normal environment. For this reason, the range of use of the
device is wide. Since a pump having a function of circulating
the liquid is provided to pulverize the bubbles in the liquid
at the time of introduction of the liquid into the device to
uniformly disperse the pulverized elements of the bubbles, the
o dispersion in the measured value of the bubble content of the
liquid is reduced. Although it is difficult to obtain accurate
data as to the bubble content of a flowing liquid in a
conventional device, the bubble content can be continuously
measured under various conditions in accordance with the
present invention to make it easier to control the quality of
each of various kinds of liquids.
The present invention can be utilized for research as well
as for practical use. Since the maximum rotational speeds of
automobile and motorcycle engines have recently been increased,
the bubble content of the lubricating oil for the engine has
become very large. The bubbles are likely to do various kinds
of harm to the hydraulic mechanism and sliding surfaces of the
engine. However, since there has not been a method for quickly
and accurately measuring the bubble content of the lubricating
oil under various conditions during the actual flow of the oil,
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zc~ s
it was difficult to fully clarify the quantitative relationship
between the bubble content and the degree and type of the
damage. The present invention can be applied for such fuli
clarification in research.
