JPS6340820A - Flow rate detector - Google Patents

Abstract

PURPOSE:To measure the flow rate of a fluid in a fine flow rate area, by arranging a pair of control ports provided symmetrical with the center line close to an inflow while being connected to a main passage through respective control nozzles. CONSTITUTION:When a fluid flowing out of a light transmitting and inflow port 4-1 is jetted into a main passage 4-3 from a main jet nozzle 4-4, it flows along either of wall surfaces of the main passage 4-3 by Coanda effect to cause a pressure difference between both sides of the main passage 4-3, which generates, for example, a flow being transmitted through one wall surface control nozzle 5-3 for the main passage 4-3, a control port 4-5 and a control nozzle 4-6. This changes the direction of the main passage to a wall surface 4-3b on the opposite side to a wall surface 4-3a while the flow is turned to a vortex. A fluid containing a pressure vibration flows in a vortex and a free end of a diaphragm 13 vibrates receiving the pressure vibration. The pressure vibration is detected with a piezo-electric film 14 thereby enabling measurement of a flow rate in a fine flow rate area.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a flow rate detector, particularly a fluid logic element in a branch flow path, and detects the pressure movement of the fluid generated in the flow path using a sensor. This invention relates to a branch type flow rate detector that measures flow rate in a minute flow rate region.

[Conventional technology]

A fluid logic element type flowmeter measures fluid flow rate by detecting fluid pressure vibrations generated in the internal flow path of a bistable fluid logic element. Compared to vortex flowmeters that detect and measure flow rates, they are suitable for detecting and digitally measuring minute flow rates.

Flowmeters used in the digital measurement of minute flow rates have been devised as positive displacement or turbine types.

However, all of these devices have movable mechanical parts as their main components, which makes the equipment expensive and difficult to maintain. Fluid logic element type flowmeters, which had the problem of being insensitive to minute flow rates as small as 1, are capable of measuring flow rates in a more minute flow range than the turbine type or positive displacement flowmeters mentioned above. Alternatively, it is possible to measure the flow rate of a low-viscosity fluid, but it has been desired to develop a device that can measure the flow rate in an even smaller flow rate region.

[Problems to be solved by the present invention]

The present invention was made from the viewpoint of ridges, and
The purpose of this is to reduce pressure loss while maintaining the measurement accuracy of the fluid logic element type flow needle using the flow dividing method, and to reduce the pressure loss of the fluid using a fluid pulsating flow sensor using a highly sensitive piezoelectric film. It is an object of the present invention to provide a flow rate detector that can detect vibrations with high precision and can measure flow rates in a microflow range that has been conventionally considered impossible.

[Means for solving problems]

Therefore, the above purpose is to provide an inflow port, an outflow port,
A V-shaped main channel is provided along the center line connecting the inflow port and the outflow port and is widened toward the outflow port, and a V-shaped main channel is provided in the vicinity of the inflow port and formed in left and right pairs symmetrically about the center line. A pair of control ports are provided and connected to the main flow path through respective control nozzles, and a pair of vents are provided symmetrically in pairs on the left and right sides of the outflow port and communicate with both corners of the ■-shaped main flow path. a fluid logic element pattern provided with a series of through holes forming a pair of through holes, and through holes corresponding to an inflow port and an outflow port of the fluid logic element pattern, provided in left and right pairs symmetrically about a center line, A manifold is formed with a control nozzle that communicates each of the vents with a corresponding control port, and has an inlet and an outlet for fluid at both ends, and has an interior that communicates the inlet and outlet with the fluid. Formed from a main flow path having a throttle member in the center, and branch flow paths that branch from the main flow path on the upstream and downstream sides of the throttle member and communicate with the inflow port and outflow port of the fluid logic element pattern, respectively. The fluid logic element pattern and the manifold are sandwiched between the main flow path housing and the main flow path housing to airtightly seal the fluid, and a sensor chamber is provided in which the fluid pulsating flow sensor described in the next section is attached. a flexible elongated diaphragm provided in the sensor chamber of the sensor casing, the tip of which is inserted into the outflow port of the fluid logic element pattern so as to vibrate freely; a piezoelectric film provided on the diaphragm, a pair of conductive films provided on the diaphragm and forming a conductive path from a pair of terminals provided on the piezoelectric film to one end of the diaphragm, and the piezoelectric film and the conductive film. This is achieved by constructing a fluid pulsating flow sensor consisting of a membrane member that covers and seals the fluid.

[For production]

By configuring it like a ridge, the fluid pulsating flow sensor can detect the pressure vibration of the fluid generated at the outflow port with high accuracy, and the flow rate can be measured in a minute flow rate region that was previously considered impossible.

〔Example〕

Hereinafter, details of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a side sectional view showing an embodiment of the flow rate detector according to the present invention, FIG. 2 is a plan view of the fluid logic element pattern shown in FIG. 1, and FIG. 3 is a manifold shown in FIG. 1. 4 is an enlarged plan view of the outflow port portion of the fluid logic element pattern shown in FIG. 1, FIG. 5 is a partially cutaway cross-sectional perspective view of the fluid pulsating flow sensor shown in FIG. 1, and FIG. FIG. 2 is a perspective view showing how the fluid pulsating flow sensor shown in FIG. 1 is installed.

In FIG. 1, 1 is a main flow path housing, 2 is a sensor housing, 3 is a throttle member such as an orifice plate or a venturi tube, 4 is a fluid logic element pattern, 5 is a manifold, 6 is an inlet port, and 7
is the outlet, 8.8′ is the main flow path, 9.9′ is the branch flow path, 10
is an 0 ring, 11 is a sensor chamber, 12 is a fluid pulsating flow sensor,
13 is its diaphragm, 14 is a piezoelectric film, 15 is an electrode plate, 16.16 is a lead wire, 17 is a mounting rubber, 18 is a sensor mounting member, 19 is a sensor lid, 20 is an O-ring,
21 is an air vent passage, 22 is a gasket, 23 is a screw, 2
4.24 is a bolt.

In the flow rate detector according to the present invention, a main flow path housing 1 and a sensor housing 2 are combined, and a fluid inlet 6 and an outflow lower are provided at both ends of the main flow path housing 1. A pipe for directly passing the detection fluid is connected to the inflow port 6 and the outflow lower, and a main flow path 8.8' is provided inside the inflow port 6 and the outflow lower along the center line. A diaphragm member 3 is provided at an approximately intermediate position, and the main flow path 8.8' branches off from the main flow path 8.8' on the upstream and downstream sides of the diaphragm member 3, and is fixed to the sensor casing 2 side. The sensor housing 2 is provided with a branch passage 9.9' communicating with the flow passages of the fluid logic element pattern 4 and the manifold 5, and the fluid logic element pattern 4 and the manifold 5 are provided between the sensor housing 2 and the main flow passage housing 1. The sensor housing 2 is provided with an O-ring 10 to airtightly seal the fluid.
1 is provided, and a fluid pulsating flow sensor 12 is provided in the sensor chamber 11.
is attached to detect the pressure vibration of the fluid generated in the flow path of the fluid logic element pattern 4, and the sensor housing 2 has an air vent flow path 2 communicating with the sensor chamber 11.
1 is provided, and a gasket 2 is provided at the end of the air vent passage 21.
1 and a screw 23 are provided.

The fluid flowing in from the piping enters the main flow path 8 from the inflow port 6, and a portion of the fluid travels straight through the throttle member 3 and reaches the outflow lower via the main flow path 8' on the outflow side. On the other hand, the remaining fluid passes through the flow path of the fluid logic element pattern 4 and the manifold 5 that constitute the fluid logic element from the branch channel 9, passes through the branch channel 91 on the outflow side, and enters the main flow channel 8' on the outflow side of the throttle member 3. At this point, both fluids merge and flow out from the outflow lower to the piping.

In addition, the pressure loss characteristics of the fluid logic element consisting of the throttle member 3 on the main flow path side and the fluid logic element pattern 4 and manifold 5 on the branch flow path side at this time are all square-law characteristics, and the phase is always equal, so that On the other hand, since the division ratio is constant, it is sufficient to measure the flow rate passing through the fluid logic element pattern 4 and the manifold S side.For example, let the flow rate on the fluid logic element 4.5 side be Ql, and the flow rate on the throttle member 3 side. When the flow rate is Q2, the confluence iQ is Q-Q+ +Q: =Q1 (1+α)=kQ.

becomes.

FIGS. 2 and 3 are plan views showing the fluid logic element pattern 4 and manifold 5 that constitute the fluid logic element.

In Figure 2, 4-1 is an inflow port, 4-2 is an outflow port,
4-3 is a 7-shaped main channel that is widened along the center line connecting the inflow port 4-1 and the outflow port 4-2 and toward the outflow port 4-2; 4-4 is the inflow port 4-
The main jet nozzle provided along the center line connecting main flow path 4-3 from 1 to 4-5' is the main jet nozzle 4-5'.
- a pair of control ports provided in a left and right pair symmetrically about the center line in the vicinity of -4 and connected to the main flow path 4-3 by respective control nozzles 4-6, 4-6'; 7.
4-7' are a pair of vents that are symmetrically provided on the left and right sides of the outflow port 4-2 and communicate with both corners of the 7-shaped main channel 4-3; 4-8 and 4-8 are mounting vents. It is a hole.

The fluid logic element pattern 4 is formed into a disk shape with a series of through holes formed by the above-mentioned symbols 4-1 to 4-7.

In FIG. 3, 5-1 and 5-2 are through holes corresponding to the inflow port 4-1 and outflow port 4-2, and 5-3.5-3'
are provided in left and right pairs symmetrically about the center line connecting the through holes 5-1 and 5-2, and the pair of vents 4-7, 4-7
' respectively to the corresponding control port 4-5.4
-5' is a control nozzle communicating with the control nozzle, and 5-4.5-4 is a mounting hole provided corresponding to the above-mentioned mounting hole 4-8.4-8.

The fluid logic element pattern 4 and the manifold 5 are overlapped to form the sensor housing 2 and the main flow path housing 1.
It is installed in such a way as to airtightly seal fluid by being sandwiched between the two.

Therefore, when the fluid flowing from the through hole 5-1 and the inflow port 4-1 is jetted from the main jet nozzle 4-4 to the main flow path 4-3, due to the Coanda effect, the fluid flows into the main flow path 4-3. Therefore, a pressure difference occurs on both sides of the main flow path 4-3, and this pressure difference is, for example, relative to the main jet flow along one wall surface 4-3a of the main flow path 4-3. Flow from the other wall 4-3b side and one pen) 4
-7, a flow transmitted through the control nozzle 5-3, the control port 4-5, and the control nozzle 4-6 is generated, so that the direction of the jet flow in the main channel 4-3 is aligned with the wall surface 4-3a. It is switched to the opposite wall surface 4-3b and becomes spiral-shaped. Thereafter, the direction of the jet stream is sequentially switched to left and right. Since the speed at which the fluid pressure waves propagate within the control flow path is constant, fluid pressure vibrations occur within the main flow path 4-3 and both control flow paths at a repetition frequency proportional to the fluid flow speed.

The fluid containing this pressure vibration flows in a spiral shape in the direction of both arrows at the outflow port 4-2 as shown in FIG. It vibrates in response to

Therefore, as shown in FIG. 4, the vortex fluid containing pressure vibrations is applied from the direction of the arrow to the diaphragm 13 of the fluid pulsating flow sensor 12 disposed at the outflow port 4-2. vibrates due to pressure vibrations generated in the fluid.

FIG. 5 is a partially cutaway perspective view showing the internal structure of the fluid pulsating flow sensor 12. In FIG. 5, 13 is the diaphragm, 14 is the piezoelectric film, 15.15 is the electrode plate, 16.16
17 is the lead wire, 17 is the mounting rubber, 31.31 is a conductive film, 32.32 is a coating member, and 33.33 is solder.

The fluid pulsating flow sensor 12 is a piezo sensor using a piezoelectric film 14, and its structure has a flexible thin and elongated diaphragm 13 made of a leaf spring as its core, and the piezoelectric film 14 is attached to one side of the diaphragm 13. A pair of 4m films 31.31 are provided on the diaphragm 13 so as to form a conductive path from the piezoelectric film 14 to a pair of electrode plates 15.15 extending to one end of the diaphragm 13. A coating member 32.32 such as a Teflon sheet is provided to cover and seal the film 31.31.

The fluid pulsating flow sensor 12 configured as described above transmits pressure vibrations of the fluid received by the diaphragm 13 as described above to the diaphragm 1.
The bending strain is detected by the piezoelectric film 14 that vibrates with the piezoelectric film 3, and the detected charge is passed through the conductive film 31.31 and the electrode plate 15.15 to the lead wire 16.16 to a digital measuring instrument (not shown). The potential from the fluid pulsating flow sensor 12 changes periodically with a phase difference of 180 degrees from each other depending on the flow velocity of the fluid, and the difference in output from both is amplified by a differential amplifier (not shown). Digital counting is performed by a pulse counter that does not operate, and as a result, the pressure vibration of the fluid is electrically detected, and the flow rate of the fluid in the minute flow rate region is measured.

FIG. 6 is a perspective view showing the mounting state of the fluid pulsating flow sensor 12. In FIG. 6, 13 is the diaphragm, 16, 16 is the lead wire, 17 is the mounting rubber, and 18 is the sensor mounting member. , 32.32 is a coating member.

The sensor mounting member 18 is provided with a slit 18a into which the mounting rubber 17 is inserted and fixed, and is also provided with a hole and a cone-shaped recess 18b for drawing out a lead wire 16.16 communicating with the slit 18a.

The fluid pulsating flow sensor 12 is mounted on a mounting rubber 1 as shown in FIG.
The sensor mounting member 18 is provided in such a way that it is inserted and fixed into the sensor mounting member 18a and becomes a free end.As shown in FIG. 19 is sealed to the sensor housing 2 by an O-ring 20 and attached by bolts 24 and 24. Sensor lid body 19 through which lead wires 16 and 16 are passed
The holes are filled with liquid rubber such as silicone to completely seal them.

〔Effect of the invention〕

Since the present invention is structured like a ridge, the present invention can reduce pressure loss while maintaining the measurement accuracy of a fluid logic element type flow meter using the flow dividing method, and Since the and manifold are configured separately, the cost can be reduced, and there is an advantage that patterns of various sizes can be combined in a set of housings.Furthermore, a fluid pulsating flow sensor using a high-sensitivity piezoelectric film can measure the fluid pressure. It is possible to provide a flow rate detector that can detect vibrations with high precision and can also measure the fluid flow 9 in a microflow range that has been conventionally impossible.

Note that the configuration of the present invention is not limited to the embodiment on the ridge; for example, although the fluid logic element pattern 4 and the manifold 5 are provided in the sensor housing 2, they may also be provided in the main flow path housing 1. , and the fluid logic element pattern 4 and the manifold 5
Either of these elements may be located on the main flow path side, and the configuration of the other elements can be freely changed in design within the scope of the purpose of the present invention, and the present invention encompasses all of them.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the flow rate detector according to the present invention, FIG. 2 is a plan view of the fluid logic element pattern shown in FIG. 1, and FIG. 3 is a manifold shown in FIG. 1. 4 is an enlarged plan view of the outflow port portion of the fluid logic element pattern shown in FIG. 1, FIG. 5 is a partially cutaway cross-sectional perspective view of the fluid pulsating flow sensor shown in FIG. 1, and FIG. FIG. 2 is a perspective view showing how the fluid pulsating flow sensor shown in FIG. 1 is installed.

Claims (1)

[Scope of Claims] A flow rate detector comprising the components described in items 1 to 3 below. (1) An inflow port, an outflow port, a V-shaped main channel that is provided along the center line connecting the inflow port and the outflow port and widens toward the outflow port, and a V-shaped main channel that is provided near the inflow port. A pair of control ports are provided in left and right pairs symmetrically about the center line, and are connected to the main flow path by their respective control nozzles, and a pair of control ports are provided symmetrically on the left and right sides of the outflow port, and the V-shaped A fluid logic element pattern with a series of through holes forming a pair of vents leading to opposite corners of the main flow path. (2) Control holes that correspond to the inflow port and outflow port of the fluid logic element pattern are provided in left and right pairs symmetrically about the center line, and communicate each of the pair of vents to the corresponding control port. A manifold formed with a nozzle. (3) It has a fluid inlet and an outlet at both ends, and has a main channel inside which communicates the inlet and the outlet and is provided with a throttle member in the center thereof, and a main channel on the upstream side of the throttle member and A main flow path housing formed of a branch flow path that branches from the main flow path on the downstream side and communicates with an inflow port and an outflow port of the fluid logic element pattern, respectively. (4) A sensor casing, which holds the fluid logic element pattern and the manifold between the main flow path casing and airtightly seals the fluid, and is provided with a sensor chamber to which the fluid pulsating flow sensor described in the next section is attached. (5) a flexible elongated diaphragm installed in the sensor chamber of the sensor housing, the tip of which is inserted into the outflow port of the fluid logic element pattern so as to vibrate freely; and a piezoelectric diaphragm provided on one surface of the diaphragm. a film, a pair of conductive films provided on the diaphragm and forming conductive paths each extending from a pair of terminals provided on the piezoelectric film to one end of the diaphragm, and covering the piezoelectric film and the conductive film;
A fluid pulsating flow sensor comprising a sealing membrane member.